A Comprehensive Review on Control Technique and Socio-Economic Analysis for Sustainable Dynamic Wireless Charging Applications

Abstract

Dynamic wireless power transfer (DWPT) has garnered significant attention as a promising technology for electric vehicle (EV) charging, eliminating the need for physical connections between EVs and charging stations. However, the improvement in power transfer efficiency is a major challenge among the research community. Different techniques are investigated in the literature to maximize power transfer efficiency. The investigations include the power electronic circuit, magnetic coupler design, compensating capacitance and control technique. Also, the investigations are carried out based on the type of wireless charging system, which is either a static or dynamic scenario. There are a good number of review articles available on the power electronic circuit and compensator design aspects of WPT. However, studies on the controller design and tracking maximum efficiency are some of the important areas that need to be reviewed. This paper provides a comprehensive review of bibliometric analysis on the DWPT technology, design procedure, and control technique to increase the power transfer and socio-economic acceptance analysis. The manuscript also provides information on the challenges and future direction of research in the field of DWPT technology.

1. Introduction

In recent years, the rise of electric vehicles (EVs) has emerged as a promising solution to mitigate environmental pollution and decrease reliance on fossil fuels. However, the limited driving range and the inconvenience of battery recharging present significant challenges to their widespread adoption. Traditional plug-in charging methods, which require a physical connection between the vehicle and charging infrastructure, pose various issues, including limited flexibility, safety concerns, and user inconvenience. Wireless charging offers a solution to these problems by eliminating the need for a physical connection, thus enhancing safety and flexibility [1].

Despite advancements in wired charging technology, it remains inconvenient for EV users due to the human handling, safety and heavy charging cable. Over the past 20–30 years, wireless power transfer (WPT) for EVs has evolved significantly, offering a modernized approach to charging [2]. WPT is categorized into static and dynamic charging: static charging occurs when the vehicle is stationary, while dynamic charging powers an EV in motion [3,4]. Early WPT systems primarily focused on dynamic charging, such as roadway-powered EVs (RPEVs), which draw energy from inductors embedded in the road. This concept spurred further research, leading to significant developments in the 1990s and early 2000s [5,6]. Notable contributions came from the University of Auckland [7] and the Korean Advanced Institute of Science and Technology (KAIST) [8], the latter pioneering online electric vehicles (OLEVs), which combine traditional EVs with RPEVs to reduce battery size while ensuring adequate driving range [9]. WPT systems have demonstrated impressive power transfer capabilities and efficiency, confirming the feasibility and potential of this technology for sustainable dynamic wireless charging applications.

The series–series (SS) topology is a favored choice among compensation networks in wireless power transfer (WPT) systems due to its independence from mutual inductance and load resistance [10]. Implementing essential controls like maximum energy efficiency tracking (MEET) and impedance matching requires precise knowledge of critical parameters, such as resonant frequency, mutual inductance, and load resistance [11]. The resonant frequency varies across WPT systems, from 87–205 kHz for electronic devices adhering to the Qi standard to 79–90 kHz for electric vehicles following the SAE J2954 standard [12]. Accurately identifying these parameters is crucial before operating the primary inverter, as even minor deviations can significantly impact performance. Researchers have explored various approaches to parameter identification, yielding significant advancements [13].

WPT systems have garnered significant attention due to their convenience and potential for various applications. In maximizing the efficiency of such systems, achieving maximum power point tracking (MPPT) is crucial [14]. Several methodologies have been proposed to optimize power transfer in WPT systems, addressing challenges such as coil misalignment, frequency tracking, and impedance matching [15,16,17]. One approach involves integrating a buck converter on the receiving side to mitigate the effects of coil misalignment, as demonstrated in previous research. Additionally, cascading a single-ended primary inductance converter (SEPIC) converter at the receiver can enhance MPPT control in magnetically coupled resonant WPT systems [18]. In dynamic scenarios, maintaining constant maximum power becomes imperative. To address this, a control strategy has been devised, ensuring optimal power delivery despite system variations or load fluctuations [19]. Furthermore, neural network-based techniques offer improved mutual inductance estimation for MPPT in wireless power transfer arrays, enhancing efficiency across varying distances and alignments. Impedance matching plays a crucial role in maximizing power transfer efficiency [20]. The utilization of DC–DC converters for impedance matching in capacitive power transfer (CPT) systems offers a promising avenue for achieving high efficiency while maintaining maximum power transfer [21,22]. Various methods have been developed to identify critical parameters in wireless power transfer (WPT) systems. For example, Ref. [23] devised a method to identify load resistance by introducing an excitation on the inverter side, which calculates load resistance based on the system’s discharge time constant or the current’s decay envelope. However, this technique is limited to purely resistive loads and fixed mutual inductance. Ref. [24] proposed using a genetic algorithm (GA) to explore the mutual inductance and resonant capacitance of multi-stage coils by sweeping frequencies between 450 and 580 kHz. Ref. [25] introduced a front-end parameter monitoring strategy for mutual inductance and load resistance for two receivers, while Ref. [26] addressed multiple receivers using a two-layer adaptive differential evolution (ADE) method. Ref. [27] focused on parameter identification based on the LCC topology of the WPT system. However, these approaches involving extensive frequency sweeping demand substantial computational resources and may only be viable on high-performance computers rather than industrial controllers like digital signal processors (DSPs). With the increasing interest in wireless charging for electric vehicles (EVs), a multitude of studies, including surveys and reviews, have explored various aspects of these systems [28,29,30].

Despite the abundance of literature, there is a scarcity of studies that comprehensively examine both the technical and non-technical facets of wireless EV charging in a single piece of work. Such a comprehensive study holds significant utility and importance for several reasons. Firstly, there is a substantial demand from government bodies, policymakers, and regulators for research that offers a state-of-the-art comprehension of wireless EV charging. They require studies encompassing feasibility analyses, economic assessments, methodologies for gauging economic advantages, pricing frameworks, infrastructure distribution models, and other planning and managerial strategies. Secondly, an exhaustive review of this topic would serve as a valuable asset for academic researchers across diverse disciplines, aiding in their understanding of the various dimensions of these systems and facilitating the formulation of novel research methodologies. Lastly, a comprehensive understanding of wireless EV charging at a system-wide level is imperative for guiding the advancement and evolution of technology. This would not only hasten the standardization of terminology, definitions, and unresolved issues in this emerging field but also foster interdisciplinary advancement and innovation. Figure 1 represents the sectional arrangements of the proposed work.

2. Methodology Bibliometric Data Extraction

The study utilized SCOPUS as the primary database and strategically selected keywords to conduct a thorough review of research on wireless power transmission (WPT) and electric vehicles (EVs) [31]. Boolean logic operators, AND and OR, were used to refine and narrow the search results. Using integrated lists of targeted keywords and the Boolean logic operators AND and OR, 2163 records were retrieved. The time frame was limited to 2011 to 2024 to ensure the inclusion of recent and relevant studies. A co-occurrence analysis of keywords highlighted the most frequent and pertinent themes in the literature, providing a clearer understanding of the research landscape. To ensure relevance, the initial keyword search results were manually screened, and documents not directly related to the application of WPT in EVs were excluded. The inclusion criteria were as follows:

• Document type was unrestricted to include all relevant re-sources.
• Research conducted between 2011 and 2024 was considered.
• Documents outside this period were excluded.
• Titles and abstracts were assessed to ensure relevance to the research topic.
• Only English-language publications were included, as it is the primary language of scientific discourse.
• Peer-reviewed publications were selected to ensure reliability and validity.
• Duplicate articles were removed to avoid redundancy.

2.1. Distribution of Bibliometric Documents and Scientometric Study

The following details indicate the number of letters, review papers, book chapters, articles, and conference papers examined in the preparation of this paper:

• The bibliometric analysis aimed to provide a comprehensive overview of the research landscape of wireless power transfer applied to EVs. Various metrics were used to analyze co-occurrence, co-authorship, co-citation, and citation patterns in the literature.
• In co-occurrence analysis, keywords, nations, and co-authors were used as measurement units. This analysis helped identify the most frequently occurring keywords, the most active nations in the field, and the most influential authors based on their co-authorship networks.
• Co-authorship analysis utilized authors, nations, and organizations as measurement units. This analysis identified collaborative networks among researchers, the most active countries in terms of collaboration, and the most influential organizations based on their co-authorship patterns.
• Co-citation analysis measured how often a particular author or source is cited by other authors or sources. This analysis helped identify the most influential authors and sources in the field.
• Citation analysis examined the citations of individual papers, authors, organizations, and sources. This analysis allowed for the identification of the most cited papers, authors, organizations, and sources, providing an overview of the most influential research in the field.
• The results of these analyses were visualized using network visualizations and density maps, offering a comprehensive overview of the intellectual landscape of the research field.

After studying and working with WPT and EVs, we analyzed the identified keywords, authors, countries, and organizations.

2.2. Keyword Co-Occurrence Study

The co-occurring term network research on wireless power transfer (WPT) and electric vehicles (EVs) is divided into eight clusters with a total of 30,876 linkages and a link strength of 6829. The size of the node labels corresponds to the number of articles using the keyword with a minimum threshold of five occurrences. The distance between nodes represents the strength of the association with a weaker association indicated by a greater distance. Fractional computations ensure that the link’s weight is proportional to the number of co-occurrences. This visualization helps identify the main research areas and the relationships between them, providing insight into the knowledge domain of the topic. The analysis suggests that the focus of research in the WPT-EV domain has shifted in recent years, with a decline in overall research output and a shift toward more specific issues related to electromagnetic shielding effects and inductive power transmission for security and safety. The emergence of new research topics such as “object detection” and “shielding efficacy” may indicate a changing research landscape and new priorities in the field. However, the study also highlights innovative techniques such as “compensation topology” and the “internet of things,” which are still being explored in the WPT-EV domain. Overall, the keyword co-occurrence analysis and time zone perspective provide valuable tools for mapping the knowledge domain and identifying trends in research focus over time.

2.3. Analysis of Author, Country, and Organization Co-Authorship

Authorship networks provide insights into the structure of collaborations within a particular field, revealing patterns of communication and cooperation between authors. This helps identify the most influential authors and research groups, enabling the promotion of collaboration and knowledge exchange. Additionally, identifying areas of collaboration between authors and research groups can highlight potential research and development opportunities.

The VOSviewer tool can generate density visualizations to identify clusters of researchers working on related topics, which is illustrated in Figure 2, Figure 3 and Figure 4. These visualizations help pinpoint potential collaborators and assess the overall structure of the field. It is important to note that the number of publications and citations does not necessarily reflect research quality or expertise level. Other factors, such as funding opportunities or research priorities in different countries, may also influence publication distribution. These limitations should be considered when interpreting bibliometric analysis results. The following sections provide the total number of authors and documents studied for this paper along with country-specific details on the number of papers analyzed. After examining all the papers and using SCOPUS to identify keywords related to DWPT for EVs, we obtained VOSviewer data. This data revealed many related sub-keywords, indicating how frequently these sub-keywords are used alongside the main keywords searched in SCOPUS.

3. Design Consideration of WPT System

Dynamic charging is the most advanced wireless charging method for EVs, where charging pads are installed on the road surface, allowing EVs to be charged while driving. The classifications of the WPT system are represented in Figure 5. This technology has the potential to eliminate the need for large batteries in EVs by enabling continuous charging. However, challenges remain, such as the cost of infrastructure installation, the efficiency of the charging process, and the safety of drivers and pedestrians [32]. Additionally, the technology is still in its early stages of development and deployment, requiring more research and testing to fully realize its potential. Overall, the shift toward renewable energy sources and the growing interest in electric vehicles are positive steps toward a more sustainable future. The development of wireless charging technology for EVs is also a significant advancement, as it can make the charging process more convenient and efficient [33].

Dynamic charging allows EVs to be charged while driving, significantly increasing their range and eliminating the need for frequent charging stops. This technology is especially useful for long-distance travel, where drivers may lack access to charging stations for extended periods. Dynamic charging also has the potential to make EVs more practical for commercial and public transportation, where vehicles often follow fixed routes and stop frequently. By incorporating charging pads into the road infrastructure, these vehicles can be charged continuously while in operation, reducing downtime and improving efficiency. However, several challenges need to be addressed before dynamic charging can be widely adopted. These include the cost of infrastructure installation, the efficiency of the charging process, and safety concerns for drivers and pedestrians. Despite these challenges, the development of dynamic charging technology represents an exciting advancement toward a more sustainable transportation system.

3.1. Coil Specification and Operating Principle

Designing the coil is indeed a critical factor in wireless power transfer (WPT) systems. The shape and size of the coils significantly affect the efficiency of power transfer, and the design must be optimized for the specific application. Typically, the secondary coil is restricted in size as it needs to be placed on the system being charged, such as an electric vehicle. In contrast, the primary coil has more flexibility in shape and size [34,35]. Various coil structures can be used for WPT, including indirect, block-shaped, hexagonal, and square designs. The coupling measure, which determines the efficiency of power transfer, is dependent on the coil design. To analyze the coupling performance of different coil structures, electromagnetic finite element modeling software, such as ANSYS Maxwell 3-D, can be used. This software simulates the behavior of the coils and provides valuable insights for optimizing coil design for maximum efficiency [36]. Overall, designing the coil is a crucial step in the development of WPT systems, and careful consideration should be given to the shape and size of the coils to ensure optimal performance. In the first experiment, a nominal power of 30 kW was transmitted over 45 mm using identical block-shaped coils with small ferrite cores on the edges for both the primary and secondary sides [37]. It would be useful to know the power transmission efficiency of this experiment. In the second experiment, a power transfer of 2 kW with an efficiency of 82% was achieved over 150 mm using a block-shaped coil design without a ferrite core [38]. This significant achievement demonstrates the possibility of transferring a substantial amount of power wirelessly without a ferrite core [39]. Finally, the group implemented a 3.7 kW wireless charging system for EVs using a block-shaped coil [40]. Knowing the distance and efficiency of power transfer in this experiment would be interesting. Overall, these experiments show promising results for using block-shaped coils in wireless power transfer both with and without ferrite cores. Further research and development in this area could lead to more efficient and practical wireless power transfer systems for various applications. Designing the coil structure is an important factor in WPT systems, and the shape of the coil can be adjusted depending on the specific needs and requirements. The primary coil has more flexibility in terms of shape than the secondary coil, which is limited due to its placement on the system to be charged [41]. The effectiveness of power transfer depends on the coupling measure, which is influenced by the coil design. Alignment between the primary and secondary coils is a major challenge, but it can be improved with the use of ferrite bars or additional intermediate coils. Adding intermediate coils can also increase power transmission capacity and efficiency. New coil designs, such as the RC coil, have been proposed to improve coupling performance [42]. The DDQ coil design has been demonstrated to have higher coupling efficiency and less sensitivity to misalignment compared to indirect and square coil shapes with low inductance values. Adding intermediate coils to the main coils has become a popular method for increasing coupling efficiency. This can be accomplished by placing one or more intermediate coils at strategic locations with an independent compensating capacitor between the primary and secondary coils [43]. A multi-transmitter coil system has also been suggested to increase transfer distance. Additionally, a new coil design called the RC coil has been proposed and compared to the DD design with the RC design showing lower losses and higher coupling performance. It is worth noting that electric vehicle operations typically use a flat helical coil structure with some operations placing more emphasis on the area of the main coils [44]. Figure 6 represents the equivalent circuit of the WPT coil and compensators.

3.2. Coil Types

Various coil shapes have been utilized in WPT systems with circular coils being the most effective for high-frequency wireless transfers due to their lack of sharp edges, which reduces eddy currents [45,46]. The high magnetic field generated by circular coils leads to superior performance in WPT systems. The charging process during electric vehicle use is considered a transient condition, and any misalignment in both longitudinal and lateral directions significantly impacts power transfer while the vehicle is moving [47].

Table 1. Different types of coils.

Coil Type	Description	Coil Type	Description
Circular [48]	The pad size is 1/4 of the height of the vertical flux pathway created by CP. The button is non-polarized and poorly misaligned. The simple system tends to serve as a transmitter in SWC. Shielding effect is reduced.	Square [49]	Higher inductance value owing to sharp edges; smaller self-inductive behavior than CP in completely aligned conditions. Hot areas and eddy currents are produced by sharp edges. Unsuitable for uses requiring high power.
Hexagonal [50]	Maximum power transfer efficiency is achieved at complete alignment. Very less power transfer efficiency is achieved at misalignment. Low leakage flux non-polarized pad that is frequently used on the recipient side.	Rectangular [51]	In terms of horizontal misalignment, RP is preferable to square and circular because the height of the perpendicular flux path it creates is half the size of the pad. Pad with a modest leakage flux that is non-polarized. The transmitter and recipient sides frequently use.
Double D [52]	Has a higher horizontal displacement tolerance than non-polarized pads. Has a large shielding effect and a polarizing pad. Has less leakage flux. Frequently applied to the transmitter side.	Double D Quadrature [53]	Better option regarding the receiver side. Polarizing pad with very little leakage flux. Generous charging area. Higher tolerance to both vertical and horizontal misalignment. Double power converters are required for run the DDQ pad.
Bipolar [54]	Better misalignment tolerance greater interoperability. A complex control strategy; the need for a pair power converters for driving the bipolar pad. A high impact of k and shielding, which is often utilized upon the transmitter and receiver side complex control strategy.	Quadrapule [55]	Complex control strategy high interoperability. Polarizing pad with a higher tolerance for misalignment and less leakage flux. Advanced control techniques are commonly used on the transmitter and receiver sides.
Flux pipe [56]	Higher shielding effect of polarizing pad with medium flux leakage. Zone of medium charge a low threshold for misalignment. Less interoperability. Frequently utilized on the transmitter side and receiver side.	Tri-polar [57]	Polarizing pads with low leakage flux, which are typically utilized on the transmitter and receiver sides, give a large charging zone. High interoperability. Larger tolerance for misalignment. Less shielding effect.

represents the different coils used for the WPT applications.

3.3. Finite Element Modeling

To improve the system’s tolerance to misalignment, a well-designed coil and impedance matching system is essential. The coil should be interoperable, regardless of the vehicle’s charging power level or coil symmetry, to ensure the system’s effectiveness. The design should also conform to international standards. The primary cost of infrastructure will determine the feasibility of the system for roadside implementation. The economic viability of the system depends on the number of vehicles that can utilize the dynamic wireless charging (DWC) system on the road. The cost will decrease as more users adopt the technology. Simulations using ANSYS Maxwell 3D software were carried out to check the flux density between coils of the same type and the current passing through the coils. The details of these simulations are discussed below.

Figure 7 above shows the flux density region and the coil structure. The coil was designed with a resonant frequency of 85 kHz. It was found that the current flowing through the coil was 10 A. The coupling coefficient used for the simulation was 0.136. The self-inductance of the transmitter was 16.3 µH, and the receiver’s self-inductance was 16.84 µH with a mutual inductance of 2.25 µH. Other geometries were also tested under similar conditions.

Figure 8 above shows the flux density region and the coil structure for a circular geometry. The coil was designed with a resonant frequency of 85 kHz. It was found that the current flowing through the coil was 10 A with a total of 19 turns. The coupling coefficient used for the simulation was 0.136. The self-inductance of the transmitter was 25.78 µH, and for the receiver, it was 21.52 µH, with a mutual inductance of 4.5 µH.

The above Figure 9 shows the flux density region and the coil structure for hexagonal geometry. The coil was designed considering a resonant frequency of 85 kHz. It was found that the current flowing through the coil was 10 A. The number of turns was 20. The coupling coefficient which was used to simulate was 0.03. The self-inductance of the transmitter was 30.16 µH, that of the receiver was 25.6 µH, and the mutual inductance was 20.9 µH.

The above Figure 10 shows the flux density region and the coil structure for double D geometry. The coil was designed considering a resonant frequency of 85 kHz. It was found that the current flowing through the coil was 10 A. The number of turns was 12 per each D shape. The coupling coefficient which was used to simulate was 0.127. The mutual inductance was 79.2 µH.

The above Figure 11 shows the flux density region and the coil structure for double D quadrature geometry. The coil was designed considering a resonant frequency of 85 kHz. It was found that the current flowing through the coil was 10 A. The number of turns was 12. The coupling coefficient which was used to simulate was 0.0585. The self-inductance of the transmitter was 28.57 µH, that of the receiver was 25.26 µH, and the mutual inductance was 19.7 µH. Therefore, by analysis of various coils in the software, the suitable choice can be made for the transmitter coil and receiver coil, and the compensation networks can be modeled, keeping in mind the various self-inductance of transmitter pads to meet the requirement of balancing of the pads. The comparisons of the above mentioned coils are given in

Table 2. Comparison of different coil structure.

Parameters	Misalignment	Interoperability	Leakage Flux	Coupling Range	Efficiency (%)
Rectangular	Intermediate	Low	Intermediate	Low	75–90
Circular	Poor	Very Low	High	Low	85–95
Hexagonal	Good	Low	Low	Intermediate	>90
DD Coil	Intermediate	Non-interoperable	Poor	Intermediate	>90
DDQ Coil	High	High	Poor	High	91–95

.

3.4. Design Objectives of Each Modules

In the above, the goals of different DWC system characteristics are outlined. The vehicle’s battery capacity will decline, as it is used more frequently on the road. Therefore, when estimating the lifespan of the DWC system, location and environmental factors must be considered. A dynamic charging mechanism can also prolong the battery’s life and enhance its effectiveness. Various topologies and configurations are employed in the design of the DWC system to ensure efficient operation.

Table 3. Different types of objectives.

Quantity	Objectives
Objectives of Control System	Unit should synchronize all the parameters and control the charging system. Generates the driving pulses to the power switches with respect to operating frequency and position of the vehicle. Indicate the presence of foreign objects on the charging lane. Detect the thermal and electromagnetic emission level on and around the track.
Objectives of Detection System	Operating time of the sensors must be synchronized with vehicle speed and system frequency. Detecting the position of the vehicle. Detecting the presence of the living object and metal object on the charging tracks. Feeds the sensed output to the controller unit. Generate the signal with respect to vehicle speed.
Objectives of Power Converters	Switches should withstand rated voltage, current and frequency. Energizing the transmitter pads by vehicle state. Generating the rated frequency input to the transmitter pad. Operating at constant voltage and current mode. Minimizing the switching losses. Provides rated constant power and battery voltage at receiver side.
Parameters of Grid Integration	Regulates the DWC system’s dynamic reaction. Power flow between grid-tied converter and grid system. Balanced voltage profile. Smooth power demand curve. Selection of peak generation source. Reducing the grid utility.
Parameters in Charging Couplers	Should transfer maximum power during lateral and longitudinal movement. Power transferring distance (air-gap). Self, mutual inductance and quality factor. Operating current and frequency. Interoperable and cost factor. Thermal dissipation system. Allowable misalignment tolerance.
Objectives of Compensation Network	L and C tunable based on resonant frequency. Reactive power compensation. Soft switching. Apparent power minimization. Bifurcation avoidance. Misalignment tolerance during load variation. Constant voltage and current maintenance.

indicated the objectives of each functional units in DWPT system.

4. Closed-Loop Control Structure of WPT

A DWPT system can be utilized for the stationary or dynamic charging of EVs. For smooth operation of an electric vehicle without issues such as heating or over-current/voltage, it is crucial to implement regulation and control on the vehicle’s charging apparatus. Regulation and control in terms of the charging apparatus involve adjusting the output voltage and current to optimally charge the vehicle’s battery pack [58]. This is essential for battery protection, smooth charging, and the longevity of the vehicle. Failure to take proper measures may result in electrical fires or battery explosions, posing risks to the user and vehicle. Therefore, the proper regulation of charging voltage and current are paramount for the overall safety of an electric vehicle. In a dynamic wireless power transfer (WPT) system, its overall efficiency depends mainly on two conditions: the coupling coefficient of the system, which changes with misalignment and the distance between the transmitter and receiver coils, and the load condition, which varies with the state of charge (SoC) of the battery. These conditions are inherent to an open-loop system, as there is no feedback mechanism to correct them. Hence, for regulating the output of the WPT system, it is necessary to have a feedback system. The presence of a feedback system transforms the WPT system into a closed-loop system. In a closed-loop feedback system, mechanisms can be implemented to monitor both the input and output parameters of the WPT system [59]. This enables corrective measures to be taken in response to deviations from normal conditions, thereby improving the overall efficiency of the WPT system. It is also essential that the feedback received on the input side is fast. Slow feedback systems with considerable delays will hinder the system’s response to abnormal conditions, potentially causing damage to semiconductor elements in the WPT system. Figure 12 depicts the setup of a closed-loop WPT system. Various control techniques are available for WPT systems, most of which are based on adjusting the input fed to the system based on the output obtained. WPT systems are primarily charged using two methods: constant current (CC) and constant voltage (CV). Control techniques in WPT systems focus on monitoring and correcting these two charging mechanisms. Proper switching between these two charging methods, along with a suitable feedback system, can increase the overall efficiency and service life of the electric vehicle battery [60].

4.1. System Profile and Closed Loop System

A WPT system comprises a high-frequency inverter responsible for increasing the frequency of the primary current, two coils for mutual coupling, and a bridge rectifier circuit with a capacitive filter to convert incoming high-frequency AC current to DC, which is safe for battery charging. The inverter configuration is a full bridge, consisting of four silicon-carbide metal-oxide-semiconductor field-effect transistors (SiC-MOSFETs). Previously, silicon-insulated gate bipolar transistors (IGBTs) were used in inverters, but they are gradually being replaced by MOSFETs, which are more suitable for industrial and commercial purposes due to their faster switching speed. Unlike MOSFETs, IGBTs have a slower switching speed and relatively limited capacity to block reverse voltage. MOSFETs have the lowest switching loss of all transistors at around 100 kHz, making them ideal for WPT systems operating within a frequency range of approximately 80 to 210 kHz, as mandated by SAE standards for systems rated below 3.7 kW [61]. This makes MOSFETs a better choice for designing inverters for low-powered autonomous vehicles or very slow-moving electric vehicles (EVs). When compared to IGBTs in terms of heat sink capacity, switching losses, and gate driver loss, MOSFETs are far superior. Silicon-carbide devices, such as SiC-MOSFETs, can operate in high-voltage range applications and have very large thermal conductivity. Hence, SiC-MOSFETs are considered the most appropriate semiconductor devices for high-efficiency power conversion. When designing a closed-loop system, it is essential to implement a controller to govern the system. The most suitable choice for a controller in a closed-loop control system is a proportional–integral (PI) controller connected to a derivative-only (D-only) controller. This choice stems from the fact that there are three fundamental types of controllers: proportional (P), integral (I), and derivative (D) [62]. Other controllers are based on combinations of these three, such as PI, PD, and PID controllers. Each of these controllers has its own advantages individually. However, when dealing with a complex system like a WPT system, accurate, stable, and fast feedback in response to changes is necessary. The PID (proportional–integral–derivative) controller is commonly used in most devices as it incorporates features of all three controllers and is stable and accurate [63]. Its only drawback is that it is slower than the PI controller. When fast response is crucial, such as in a WPT system, it is preferable to use a PI controller. The feedback control loop calculates errors by comparing the output signal of the system to a setpoint value, which is periodically adjusted based on the state of charge (SoC) percentage of the battery [64]. The PI controller controls the feedback from the primary side and has low sensitivity to noise, minimizing errors in steady-state conditions, which is crucial for maintaining constant current (CC) and constant voltage (CV) charging. Based on data provided from the secondary side, adjustments can be made to the input from the primary side. On the primary side, sinusoidal pulse width modulation (SPWM) control can be implemented. SPWM controls the pulses of the MOSFET switches, which in turn control the operating frequency, enabling the generation of input and output voltage as required by the secondary side. This helps determine the appropriate charging mode between CC and CV [65]. While the controller can provide feedback, suitable control structures and methods must be implemented to act upon this feedback effectively.

4.2. Control Structure

In the WPT system, there are two modes of charging the battery. In the initial stage, when the DC link is established between the primary and secondary sides of the system, the mode of charging is constant current (CC) charging. When relative stability is achieved between both sides of the system (primary and secondary side voltages are nearly the same), the constant voltage (CV) mode of charging is used for the battery. Hence, to regulate the WPT system, it is necessary to implement separate control systems for both charging mechanisms. To facilitate both, a “control structure” and a “control method” are required [65]. A control structure refers to a topology indicating which component of the system will be subjected to regulation with respect to its location in the system. An algorithm that offers instructions or steps to control the system is referred to as a control technique. Control structures used for regulating current and voltage for charging can be divided into four main groups with various sub-variations. Figure 13 shows the most common control structures applicable to WPT systems. These control structures are as follows:

• Inverter control;
• Impedance matching (IM);
• Dual-side active bridge control (DAB);
• DC level control.

Control structure 1 is a single-sided control structure, while control structure 4 is a double-sided control structure. In inverter control, phase shift or frequency control is mostly used and is the most commonly used control structure for WPT and IPT systems. This method is preferred due to its simple structure, use of fewer components, and smaller size. The sinusoidal pulse width modulation (SPWM) method is mostly used as it can easily change the frequency as needed [66]. The IM control structure is primarily applied to high-frequency, low-power applications. In this structure, there are a number of capacitors, inductors, and relays or switches on both sides. The capacitors and inductors significantly change the output voltage to balance the impedance mismatch caused by the primary-side converters and the loads, thereby decreasing the output voltage. However, due to the large configurations of capacitors and inductors, the system becomes bulky and complicated, leading to increased control complexity. This makes it unsuitable for WPT systems where the load is subject to change. The dual active bridges (DABs) have the lowest conduction losses and are used to overcome the drawbacks of single-side controlled power transfer systems. They also have characteristics such as power regulation, load transformation, and compensation for reactance, allowing both the primary and secondary sides to have independent control [67]. One of the most useful features of DABs is that no feedback link is required between both sides. However, the drawback of this system is its large size and the very large number of semiconductor components. In the DC level control structure, a DC–DC converter is present on both the primary and secondary sides of the system. The converters used can be buck, boost, or buck–boost type. In the control methods applied to this type of structure, the converters on both sides work independently, eliminating the requirement for any feedback link [68]. The primary side converter regulates the input voltage, while the secondary side regulates the output voltage. The most common setup using this type of control is to have a boost converter at the primary side before the inverter section and a buck–boost converter at the secondary side to adjust the output as required.

Table 4. Comparison of different control approaches.

Control Structure	Description	Applications	Advantages	Disadvantages
Inverter Control	Uses phase shift or frequency control, often with sinusoidal pulse width modulation (SPWM).	Most WPT and IPT systems	Simple structure, fewer components, smaller size	Limited to single-sided control
Impedance Matching (IM)	Uses capacitors, inductors, and switches to balance impedance mismatch.	High-frequency, low-power systems	Can balance impedance mismatch effectively	Bulky, complex, not suitable for changing loads
Dual-Side Active Bridge (DAB)	Employs independent control on both primary and secondary sides without feedback link.	Overcoming single-side drawbacks	Low conduction losses, independent control, power regulation	Large size, many semiconductor components
DC Level Control	Utilizes DC–DC converters (buck, boost, or buck–boost) on both primary and secondary sides.	Systems requiring independent control	Independent operation on both sides, no feedback link required	Complexity due to multiple converters

indicates the comparison of different control techniques used in WPT.

Figure 13. (a) Inverter control, (b) impedance matching, (c) DAB, and (d) DC level control.

Figure 13. (a) Inverter control, (b) impedance matching, (c) DAB, and (d) DC level control.

4.3. Control Methods

To achieve maximum efficiency and power transfer, various control techniques are applied. In a WPT system, several signals are fed into the inverter from the front-end converter. These signals have different phase angles and phase shifts. The sinusoidal pulse width modulation (SPWM) control method is primarily used to regulate the phase shift and phase angle. A straightforward duty cycle is maintained for constant current (CC) and constant voltage (CV) charging, which helps to keep the primary side’s output steady. The system’s architecture may also influence this process [69]. Frequency and phase control techniques are commonly used with a voltage source inverter (VSI) located on the primary side. With VSI, variations in phase shift between bridge legs, switching frequency, or the DC-link voltage are often observed. However, these techniques are complex and expensive for low-power applications. Using a dual mode of charging ensures a secure charging procedure and prolongs the battery’s operation. Initially, the battery is charged with a current set at a level equal to the battery’s capacity (CC mode of charging). This charging mode is maintained until the charging voltage is reached, at which point the charging mode is switched to CV mode [70]. If the battery has been deeply drained, the maximum current can be used in CC mode. Once CV mode is applied, the current starts decreasing to a minimum value. To carry out the aforementioned process, data from voltage and current sensors on the receiving side are converted using an analog-to-digital converter (ADC). This is typically achieved by employing a microcontroller supplemented with a PI controller to supply the inverter switch drivers. Figure 14 shows the EV battery-charging profile.

4.4. Wireless Feedback Systems

Another method to generate feedback for WPT is by transmitting data wirelessly. Distorted or delayed feedback data can cause problems in the overall operation of the system. Therefore, accurate charging process control requires the constant and uninterrupted recording of output voltage and current data. It is suitable for the frequency of transmitted data between the primary and secondary sides to be higher than the operating frequencies of the WPT system [71]. This would ensure that the closed-loop feedback system operates correctly and steadily. For dynamic charging scenarios, industrial-level wireless networks are preferable due to real-time monitoring, minimal transmission loss, better performance, security, and range. However, such networks are not suitable for domestic or consumer applications due to their high cost. Using a mobile device or local area network for transmitting feedback data is feasible. Mobile networks (GSM, CDMA) offer coverage over several kilometers, while local networks like Wi-Fi, Bluetooth, and ZigBee have a smaller range [72]. Dedicated short-range communication (DSRC) and cellular networks have very short transmission delays compared to global wireless networks like FM radio or satellite. For static charging using WPT, where the maximum transmission distance is in the centimeter range, networks are not necessary. One of the main drawbacks of a wireless mode of feedback is that the data are sent in small packets, which may be lost due to external factors such as noise or frequency overlapping. Additionally, as the distance between receivers of the feedback module increases, the signal-to-noise ratio decreases, deteriorating the signal. These factors contribute to transmission delays, which is one of the most notable reasons wireless feedback systems are not commonly used [73]. Other feedback systems currently under study and research include the frequency multiplexing method, which is an emerging trend. In this method, feedback from the secondary coils can be transmitted to the primary coils via the same inductive link used for power transfer. The main advantage of this method is that it eliminates the need to establish a separate communication channel for data transfer [74].

4.5. Power and Data Frequency Division Multiplexing (FDM)

In the FDM (frequency and data multiplexing) method-based closed-loop WPT system, a key feature of the setup is that the communication link does not affect the speed of data transfer or the method of power transfer. To implement FDM, a data transmitter and data receiver are added to the primary and secondary sides, respectively. Both the data transmitter and the data receiver are magnetically coupled with the resonant inductive tank [75]. Figure 15 depicts the basic setup of the FDM-based WPT system.

Using ferrite-core coupled inductors, the data transmitting and receiving devices are magnetically coupled to the resonant tank. The transmitter sends data in the form of ones and zeros by alternately switching on and off. This allows information bits to be transmitted to the receiver side. The data receiver is designed to filter the power carrier and obtain a sufficient amplitude of the data carrier signal. To properly implement power and data frequency division multiplexing, the data carrier frequency should be much higher than the power/operating frequency of the WPT system. If the frequencies are not significantly different, they may mix and cause transmission problems. For example, if the power/operating frequency is around 80 kHz, then the data carrier frequency needs to be in the range of 2–3 MHz. Microcontroller units (MCUs) are present with both the data transmitter and receiver to control the power carrier signal and the feedback data signal. The primary-side MCU measures the phase shift angle required to control the inverter, while the secondary-side MCU samples the output data and transmits it to the primary-side MCU [76]. Phase shift control is the most suitable mechanism to control the inverter output in the primary because of the multiple signals and frequencies involved in an FDM-based WPT setup. In such closed-looped WPT systems, it is necessary for the coils used to be coreless to prevent losses, and simple compensation networks like SS, SP, PS, and PP should be employed. The data being transferred need to be modulated and demodulated for the transfer process. However, implementing a closed-loop feedback system is costly and complex. Nonetheless, for stable output and proper regulation of the system, a closed-loop system is essential. These closed-loop systems are imperative for achieving maximum efficiency in a WPT system, as discussed in the next section.

5. Maximum Efficiency Tracker in WPT System

In a dynamic wireless power transfer system (WPT), the primary and secondary coils are separated by air, resembling a “loosely coupled” transformer. This means that a portion of the flux generated at the primary side does not link with the secondary side but instead dissipates as leakage flux, leading to stray heat generation. This results in voltage drops in the secondary side and acts as a high series reactance in the primary side, thus degrading the overall system efficiency [77,78]. Additionally, variations in system load and the coils’ coupling coefficient affect the WPT system. In practical terms, in a WPT system, changes in load are associated with variations in the charging state of the vehicle’s battery, while changes in coupling coefficient are related to the relative position between the coils. Therefore, implementing maximum efficiency tracking (MET) control in the system is essential to enhance overall efficiency. The fundamental idea behind MET involves tuning the equivalent load control present on the secondary side to an optimal value through impedance conversion. Impedance conversion, in simple terms, aims to match one impedance to another [79]. Electrically, it involves matching the load impedance to the source or internal impedance of a driving source. This principle is rooted in the maximum power transfer theorem, which states that to transfer maximum power from a source to a load, the load impedance should match the source impedance. In a WPT system, the AC source drives the load, which in this case is the equivalent resistance at the secondary side. Impedance matching or conversion can be achieved in various ways to enhance the overall efficiency of the system. Impedance conversion can be classified as follows.

5.1. Impedance Matching Using Passive Impedance Networks

The impedance-matching approaches in magnetic resonant coupling WPT at a fixed resonant frequency, using passive impedance networks, can be broadly categorized into two types: the mutual inductance tuning method and the capacitance tuning method. These methods are typically implemented using large inductor and capacitance networks, which need to switch periodically to achieve impedance matching, especially in WPT systems where the equivalent resistance may change. However, such networks are bulky and complicated to operate [80,81]. Hence, this technique is not suitable for WPT systems due to their complexity.

5.2. Impedance Matching Using Active Rectifier

Impedance matching using an active filter is achieved by diverting the power intended for the load elsewhere through shunting. The impedance can be regulated at the time when the power is being shunted [82]. The topologies used in this method are simple in nature, but the rectifier must be managed, and the impedance can only be decreased with no means of increasing it if required.

5.3. Impedance Matching Using DC–DC Converters

This method is widely used because it can achieve a large range of impedance conversion. It is also suitable for a WPT system to achieve the maximum possible efficiency because a typical WPT setup includes converters at the input and output sides to meet specific requirements [83,84,85].

5.4. Maximum Efficiency Tracking Using DC–DC Converters

There are three types of DC–DC converter topologies available for use with the WPT system: (i) buck, (ii) boost, and (iii) buck–boost, as shown in Figure 16. These DC–DC converters operate in two modes: continuous conduction mode (CCM) and discontinuous conduction mode (DCM). The operation of a DC–DC converter in either CCM or DCM depends on the inductor current characteristics. In CCM mode, the inductor in the switching regulator always maintains a non-zero current [86]. On the other hand, in DCM mode, the inductor current depends on a pulse width modulation (PWM) signal, and it drops to zero until the next pulse is applied, typically occurring when the duty cycle is too short or under very light load conditions. Essentially, the DC–DC converter controls the output voltage using the duty cycle (D). The duty cycle represents the ratio of the turn-on time (T_ON) to the total cycle length, which includes the turn-off time (T_OFF) plus (T_ON). The duty cycle establishes a simple relationship between the input voltage (V_IN) and the output voltage (V_O).

$$D={\displaystyle \frac{T_{ON}}{T_{ON}+T_{OFF}}}$$

(1)

Since the inductor has current in both ON and OFF states, the overall variation in current in both the states should be equal to zero. The ON and the OFF state are determined by the gate voltage (high or low). If the gate voltage is high, current flows from drain to source, allowing current to flow from inductor to load. If the gate voltage is low, current does not flow from drain to source. This causes current stored in the inductor to flow to the diode and the load.

$$∆I_{ON}+∆I_{OFF}=0$$

(2)

The relation between the self-inductance of the inductor (L), inductor voltage (V_L) and the current can be expressed as

$$V_L=L{\displaystyle \frac{∆I}{∆t}}$$

(3)

The relationship between input and output voltages, input resistance and load resistance can be obtained by using the above three equations for all three converters. The mode of operation to be considered while deriving these relationships is CCM.

5.5. Maximum Efficiency Tracking Using Other Methods

5.5.1. MET Using Magnetic Resonant Coupling

In a WPT system, power is transmitted inductively utilizing a pair of coils and resonant magnetic coupling. The relationship between the coupling coefficient k and the mutual inductance M of the coils is shown below:

$$k={\displaystyle \frac{M}{\surd L_1{L}_2}}$$

(4)

where L₁ and L₂ represent the primary and secondary-side coils’ self-inductances. The power transfer capacity can be improved; the voltage and current stress could be lowered at the source and the load by establishing resonance at the transmitting and the receiving sides, respectively. Some basic resonant topologies are present at the moment which can satisfy the above requirement. These topologies are SS, SP, PS and PP. The capacitive compensations are also present in these topologies. The circuit in this type of system can be propelled by an AC current or voltage source. The SS topology, one of the four fundamental topologies, exhibits power source reactance that is independent of the coupling coefficient or load resistance at the side that receives resonance frequency. The receiving side and transmitting side resonant frequencies are obtained by

$$\omega ={\displaystyle \frac{1}{\sqrt{L_n{C}_n}}}$$

(5)

where n = 1 or 2 depending on whether it is the transmitting or receiving side. At this frequency, it is on the receiving side. There is no longer any power reflection to the transmitting side. The size of the primary and secondary-side resonant currents affects how much power is lost in the WPT system, which also includes radiation, conduction, and switching losses in power semiconductors. For simplification of the estimation of efficiency of a WPT system, all the losses are considered as one represented by equivalent series resistances (ESRs) R1 and R2. Closed-loop systems provide a constant output voltage even while both the load and the coupling factor are varying. Different variables can be used to control the output in a closed-loop WPT system, as shown in Figure 17.

Various closed-loop schemes can be used to achieve such regulations [87,88]. Some closed-loop schemes like pre and post are shown in Figure 18 are discussed above.

5.5.2. Pre-Regulation Scheme

In this scheme, the operating frequency of the system remains unchanged. A DC–DC converter on the transmitting side can be used to linearly modulate the system’s output voltage [89,90]. The input voltage conversion ratio is considered as the control variable. The voltage gain from the DC/DC converter and the voltage gain between the inverter’s input to the rectifier’s output determine the system gain.

5.5.3. Post-Regulation Scheme

A DC–DC converter on the receiving side can control output voltage. The load-to-power ratio is considered the control variable [91]. Because the DC–DC converter on the receiving side converts the equivalent load resistance, the load conversion ratio affects the voltage gained from the inverter’s input through the rectifier’s output. Now, to implement an MET control scheme, a maximum efficiency point has to be determined using one or more control variables that regulate the output. When using magnetic resonant coupling as an MET control scheme, the maximum efficiency point is where the operating frequency is equal to the receiving-side resonant frequency:

$${\omega }_1={\omega }_2$$

(6)

To eliminate the possibility of power reflection, the equivalent load resistance matches its optimum value.

$$R_{Eq}=R_{opt}=\sqrt{{1+fm}^2}{R}_2$$

(7)

The figure of merit is related to the mutual inductance and coupling coefficient in order to reduce ESR losses.

$$fm={\displaystyle \frac{\omega M}{\sqrt{R_1{R}_2}}}$$

(8)

The efficiency can be given by

$${\eta }_{max}=1-{\displaystyle \frac{2}{1+\sqrt{1+{fm}^2}}}$$

(9)

The operating frequency is fixed by the MET control mechanism to be the same as that of the resonance frequency of the receiving side. It uses a DC–DC converter to change the load resistance so that it matches an analogous load resistance to its ideal value in (7). Simultaneously, input voltage is regulated by another DC/DC converter in the transmitting side to regulate the system’s output voltage. Even though the optimum equivalent load can be calculated, according to (7), ESRs are not actually constant, and placement affects mutual inductance. Hence, the maximum efficiency point needs to be tracked continuously.

5.5.4. MET Using Phase Shift and Frequency Control

This control method is similar to impedance-matching methods. In this technique, the source impedance is matched to the load impedance [92]. In this method, both the voltage output of the inverter’s frequency and phase shift varied in order to reduce the input power where the output power remains the same by using a DC–DC converter [93]. Figure 19 represents the flow chart of the procedure to realize this technique.

The above algorithm is split into two sections. The algorithm’s first half looks for the best switching frequency value. The second half of the procedure involves determining the ideal phase shift value for the ideal switching frequency. The algorithm performs the following actions while running:

• A starting phase angle of 900 is applied, and the switching frequency is taken by finding the mean of the allowable range of frequency with the current frequency and applying it to the high-frequency inverter.
• The duty cycle is adjusted to regulate the charging current and voltage depending on the SoC of the battery.
• Calculating input power from the DC-link voltage and current.
• The phase shift is optimized with a starting number of 100% on time and the optimized switching frequency value after the switching frequency has been optimized.
• While buck converters maintain constant output power, phase shift is optimized to reduce input power.
• Finally, the optimized value of both phase shift and frequency are obtained, and the cycle is repeated after a timed delay.

Hence, by using the above algorithm, maximum efficiency could be tracked. Therefore, we can have an idea about various techniques and algorithms which can be used to achieve the maximum efficiency tracker of a wireless power transfer system in electric vehicles.

6. Social, Economic and Technical Factors of DWPT

Electric road systems (ERSs) represent a promising innovation that could revolutionize electric vehicle charging. ERSs involve electrified roadways enabling continuous charging while vehicles are in motion, eliminating the need for frequent recharges. This technology could alleviate range anxiety, extend the range of electric vehicles, and make long-distance travel more feasible [94]. While not entirely new, ERSs have been piloted in various countries to test feasibility, such as the eRoad Arlanda project in Sweden, using conductive technology, and the dynamic wireless charging (DWC) project in California, utilizing wireless power transfer [95]. However, ERSs are still in experimental phases, facing challenges like infrastructure cost, compatibility with different EVs, and safety concerns with high-voltage systems. Yet, ongoing research and development could integrate ERSs into the vehicle fleet, reducing transportation sector emissions. For widespread adoption, ERSs must be cost-effective, scalable, and compatible with existing infrastructure, ensuring a seamless charging experience without compromising vehicle performance or road safety. Governments, industry stakeholders, and researchers need to collaborate to overcome these challenges and facilitate ERS deployment through investment, standards development, and regulatory frameworks. The Paris Agreement aimed to limit the global temperature rise to below 2 °C compared to pre-industrial levels with efforts to further reduce it to 1.5 °C. However, current projections indicate that we are not on track to meet these targets. Urgent action is needed to reduce greenhouse gas emissions and mitigate the impact of climate change. The UNEP report underscores the significant disparity between the emissions reductions necessary to achieve the goals of the Paris Agreement and the commitments outlined in countries’ Nationally Determined Contributions (NDCs) [96]. More ambitious targets and actions are essential to effectively reduce emissions and address the impacts of climate change. The PEST (political, economic, social, and technological analysis) framework is a strategic tool utilized to analyze external factors that could affect a business or project, representing political, economic, social, and technological aspects [97]. In the context of research on DWPT and ERS, the PEST framework was employed to identify factors influencing the utility and functionality of the technology.

Key points regarding the PEST framework include the following:

• The PEST structure, designed to explore the macro-environment, was adopted as part of the research effort [98]. PEST encompasses political, economic, societal, and technological forces within the system.
• Unstructured conversation, a qualitative, informal, guided methodology, aims to understand one’s experiences and perspectives within a modified social setting [99], striving to attain the same level of expertise and understanding as the respondent [88]. In-depth, partially structured discussions aim to uncover hidden motivations, biases, or attitudes toward sensitive topics.
• A swift review of available information was conducted as a time and resource-efficient strategy [87], yielding relevant data to support the analysis phase.

6.1. Stakeholder Selection

The aim was to comprehensively understand the study environment. This required identifying individuals who could provide insights into the specific subject and context under investigation. The intrinsic political, economic, societal, and technological factors of the PEST framework were aligned with the categories used to select stakeholders, ensuring a diverse representation of perspectives [100]. Participants were divided into four groups: policy, consumer, business, and technology. There were 38 participants in total, representing 20 different organizations. The participants included academics (21%), highway and transportation authorities (37%), energy suppliers (10%), bus operators (3%), solution providers (21%), and automakers (8%) [90]. Figure 20 shows the Venn diagram of stakeholder selection.

6.1.1. Transcribing

After the incident, the generated data were prepared for analysis. The discussion transcripts underwent qualitative (thematic) analysis to identify patterns, themes, and meanings, facilitating a comprehensive understanding of the phenomenon under study. Qualitative analysis is viewed as an iterative, critical, and reflective process that involves switching between the data, analysis, and the overall structure of the research to maintain a holistic perspective [98]. The statistics should be able to confirm or refute the analysis if it was thorough and transparent. The data needed to support or challenge our ideas should not be manipulated to fit a predetermined narrative; this is a crucial aspect.

6.1.2. Analysis

The final step of the methodology involved validating and reporting the analysis results. Verification concentrated on assessing the “reliability” (the consistency of the results) and “validity” (whether the study accurately addressed its intended objectives) of the information [101]. This was achieved by comparing the analysis findings with the infrastructure requirements for EV charging discussed in the background section and confirming their necessity through a brief literature review.

6.1.3. Results

The discussions in the focus groups encompassed a wide range of subjects, including the current state of EVs, consumer behavior, EV technology, grid and transportation network impacts, and policy and standard requirements, all of which fall under two main categories. The subsequent section covers the key topics that emerged in the focus group discussions.

6.1.4. Policy

This section discusses participants who are expected to play upcoming roles in developing and overseeing policies in the environment surrounding DWPT along with other stakeholders who have experience in policy creation and/or delivery.

6.1.5. Cost

To attract prospective public or private investors to invest in a dynamic wireless charging network, a compelling business case is necessary, given the high capital costs involved. These investors might perceive the return on investment of the technology as uncertain, considering it is relatively novel. Policymakers may face challenges in developing business cases for its use due to data availability issues. Therefore, it is essential to emphasize the importance of considering the future EV market and user requirements when constructing the economic case.

6.1.6. Infrastructure Location

Success hinges on selecting the optimal location for the infrastructure. According to a comment, the dynamic wireless charging solution (DWCS) should seamlessly integrate with existing charging infrastructure in the region. One strategy to manage costs for users is to foster competition within the dynamic charging market. There should be minimal restrictions on installing infrastructure along the chosen road. Electrifying major roadways, such as motorways and primary roads, was considered more feasible. These road networks are typically well maintained and offer ample space for essential utilities.

6.1.7. Temporal Considerations

The solution’s effectiveness could be compromised by disruptions that may occur during the construction phase, potentially leading to the loss of rights for individuals. Therefore, installations must be completed within a relatively short timeframe to minimize highway closures. Considering all future needs could significantly increase the cost of designing and implementing the solution.

6.1.8. User Considerations

It was emphasized that a road-based charging option is needed to accommodate various vehicle and user types. DWCS will, however, be better for business users who do not travel short distances and follow set paths, according to the general consensus. Changing consumer behavior was ranked as one of the major obstacles to the successful implementation of this charging method [102]. Activities involving the public are considered essential for spreading the technology. It is crucial to empower the user because only they can decide whether to use the recharge station. Having a clear costing structure and a secure, convenient payment method is essential.

6.2. Consumer

In particular, stakeholders who are likely to play a significant role in determining how DWPT is likely to be utilized, including behaviors involving the purchase of DWPT-compliant cars, are discussed in this section. They have experience with established use cases concerning charging infrastructure [103]. Figure 21 shows our Venn diagram of the consumer’s role in WPT.

6.2.1. Capital Cost (Provider)

Public charging stations will continue to be essential for the widespread adoption of electric vehicles. The number of charger units needed to satisfy future demand (rapid static charging) may decline because of DWPT [104]. However, user concerns about a relatively new charging solution might impede the acceptance of DWCS. Similarly, potential users might express concerns about hydrogen-based fuels, since the primary target vehicle types for the technology—buses and heavy goods vehicles—are becoming the preferred option. To expand the user base, stakeholder approval of the product, evidence of the technology’s durability, and DWCS support from national and local governments were deemed essential.

6.2.2. User Behavior

The facility’s usage depends on transportation patterns within the designated infrastructure location. Key factors influencing charging decisions include the variety of vehicles, individual preferences, traffic flow, storage capacity, state of charge (SoC) thresholds, and the daily mileage of specific vehicle types [105]. Implementing automated or manual decisions to maintain the necessary SoC levels requires intelligent battery management solutions.

6.2.3. Capital Cost (User)

Commercial users, such as those in public transportation services (taxis, buses, and vans), last-mile delivery services, and haulage firms, would be the main drivers for DWPT [106] technology. Additionally, dynamic wireless charging could enable businesses to purchase more economical, smaller electric vehicles. As commercial users often prioritize cost, the solution must be more cost-effective than other forms of car charging [107]. By reducing the size of the battery pack, dynamic charging can help reduce the cost of the vehicle.

6.2.4. Operational Cost User

The demands placed on the power grid are expected to increase as the number of vehicles equipped with DWPT technology is adopted. The interaction between vehicle demands and traffic flow puts clear pressure on the grid. Intelligent pricing strategies are crucial to reduce strain on the grid during peak electricity consumption times. However, it was also noted that business users, who prefer to anticipate energy costs for calculating their operating expenses, might not find variable pricing appealing. Therefore, a contract between prospective large-scale commercial customers and the consultant is necessary.

6.3. Business

The segment discusses the opinions of those involved in the creation and use of a business model centered on DWPT [108], particularly those who may play a role in overseeing the implementation and evaluation administration of a DWPT solution in the future. Figure 22 shows the Venn diagram of business.

6.3.1. User Engagement

The user group places a high value on the standardization of the technology and its compatibility with various vehicle types [109]. The primary customers for DWPT are anticipated to be business users. Therefore, it was expected that targeting companies rather than individuals would be the main business strategy for this charging option. Users can learn more about the system and its advantages through resources such as outreach programs and advertising signage.

6.3.2. User Behavior

It is typical for private car owners to retrofit the receiver and other necessary components without considering the vehicle’s aesthetics. Mobile charging may affect driving habits. Drivers may prefer to change their driving habits because DWPTs generally encourage driving slowly. It is important to assess how this will affect traffic flow. A vehicle’s charging ability is influenced by several external variables, including the power systems, traffic flow, and the power used by other vehicles positioned on the same coil segment. Users’ trust in the technology may decline due to this pricing variability.

6.4. Technology

The section examines the opinions of those involved in the background creation of the technology involved, particularly those involved in providing DWPT solutions to the market in the future. Figure 23 indicates Venn diagram of technology.

6.4.1. Stakeholder Communities

The smooth functioning of the DWPT infrastructure depends on effective communication among key parties, which include roadway and utility operators, utility providers, transportation authorities, and municipal governments.

6.4.2. Product Standards

Standards specifically created to address the safety and technical aspects of DWPT technologies are essential for the technology’s successful commercialization. Addressing potential issues related to electromagnetic fields (EMFs) and electromagnetic compatibility (EMC), which could pose risks to health and safety, is crucial. To minimize risk to other nearby drivers and pedestrians using the road, it is crucial that only that specific segment be activated when a vehicle passes over it and transfers energy to the receptor on that vehicle.

6.4.3. Performance Improvements

The gap in the air and horizontal imbalance between both the transmitters and the receivers have an impact on the system’s ability to effectively transmit electricity. It seems that using information and communication might be necessary to alert the driver, which is used to create the needed adjustment to increase coupling efficiency.

6.4.4. Performance Management

The grid may experience varying power consumption patterns due to the connection of many electric cars that arrive and depart at various times and travel at various speeds, which could lead to power quality problems such as the introduction of harmonic currents. Furthermore, if the peak demand period for the charging facility and DWCS overlap, DWCS may add more load to the grid during that time [110].

6.5. Discussion

The research confirmed several elements, including various difficulties, that contribute to the effectiveness or potential advantages of the DWPT system. For EV adoption to become more widespread, suitable charging facilities must first be installed. Rapid charging, fast charging, and slow charging are just a few of the charging infrastructure solutions being implemented across the nation. They collectively create a charging environment that satisfies the needs of location and opportunity charging. The efficacy of the DWPT charging network will ultimately be decided by the variety and number of users provided the initial cost is adequately amortized. Participants stated that technology usage in early deployment scenarios needs to be maximized. Business users who travel long distances on predetermined, recurrent paths are recommended as the first target users. The majority recommend the implementation of DWPT systems across transit lines in cities, in addition to short or long-distance national and foreign freight corridors, which is supported by the literature. Predicting the energy needs of potential EVs that will utilize the facility is essential to build stakeholder support for the DWPT charging infrastructure [111]. Key externalities were found in the focus group’s findings and confirmed through the literature; these externalities were then categorized into eight taxonomy categories, as shown in Figure 24.

6.5.1. Positioning

These external factors influence whether the vehicle will seek a charge, depending on the vehicle’s condition, such as the current state of charge (SoC) of the battery.

6.5.2. Battery Capacity

Depending on the specific mission, these external factors influence whether the user will request a charge. For instance, while traveling, the driver could optimize the battery range based on the journey’s needs.

6.5.3. Daily Load Curve

These external factors determine the type of charge that will be produced; for example, at a series of charging stations, the energy transferred will depend on the vehicle’s speed.

6.5.4. Speed

Based on economic factors and alternatives, such as availability and the cost per unit of energy, these externalities determine whether a charge will be requested.

6.5.5. Traffic

These external factors influence the demand placed on the DWPT system, including the volume and type of traffic using the system.

6.5.6. Infrastructure Air Gap

These externalities influence the decision of the larger user population to embrace DWPT based on the system’s accessibility both geographically and functionally, such as whether it is offered on the user’s route options.

6.5.7. Road Gradient

Recent research has shown that the rate of energy regeneration is more influenced by the gradient than the energy consumption rate, having different effects on vehicle energy consumption and regeneration. Therefore, the accurate modeling of road gradients is necessary for optimizing electric vehicle energy management strategies.

6.5.8. Charging Infrastructure

The EVSE is an essential component of the EV charging infrastructure, enabling the safe and controlled transfer of power from the electrical grid to the vehicle’s battery. Typically, the EVSE consists of a charging station and a connector, which may be either a wired or wireless connection, which is responsible for managing the power flow between the grid and EV. The control system in the EVSE ensures that the charging process is safe and efficient by monitoring the charging status, managing the power output, and communicating with the vehicle to regulate the charging rate. Figure 25 indicates the chart of taxonomy.

The aggregation of the aforementioned externalities is crucial in determining demand, as they may influence the implementation of DWPT in a positive or negative manner, along with the variables that work together to determine demand. The research from the survey discussions led to the creation of the taxonomy’s structure. Road transportation is acknowledged to be a complicated system that calls for a variety of solutions, including advancements in car design and cutting-edge charging infrastructure. Electric road systems (ERS), and more specifically, dynamic wireless power transfer (DWPT), are one possible innovation because they have a broader market appeal than alternatives. In order to implement suitable solutions, it is necessary to identify the obstacles prior to implementing ERS. One problem is that present technocentric approaches fail to adequately take into account the complicated interactions between organizations, the individuals carrying out business processes, and the systems supporting these types of interactions, which is also seen in DWPT [112].

7. Challenges and Limitations of DWPT

Effective magnetic coupling is essential for achieving high power transfer efficiency, especially during lateral misalignments. The interoperability and integration of DWPT systems with existing infrastructure and EV technology need to be addressed for wider adoption. The construction and embedment of e-roadways, which require significant investment and infrastructure development, pose a significant challenge for DWPT systems’ implementation. Compensation network architecture needs to be designed to mitigate parasitic losses and improve power transfer efficiency. Finally, health and safety concerns related to exposure to high-frequency electromagnetic fields need to be addressed through proper regulatory frameworks and safety standards. Addressing these challenges and limitations can unlock the full potential of DWPT EV charging systems for future transportation systems. Below, we discuss these in detail.

7.1. Wireless Magnetic Coupler

One of the major challenges in dynamic wireless power transfer (DWPT) systems is ensuring effective magnetic coupling between the transmitter (Tx) and receiver (Rx) coils. The magnetic field produced by the Tx coil should be strong enough to induce a voltage in the Rx coil even when the two coils are misaligned or moving relative to each other. The effectiveness of magnetic coupling depends on several factors, such as the distance between the coils, the size and shape of the coils, and the frequency of the magnetic field. As the distance between the coils increases, the strength of the magnetic field decreases, resulting in reduced power transfer efficiency (PTE). To address these challenges, research is ongoing to optimize the design of the Tx and Rx coils in addition to the frequency and power level of the magnetic field. Additionally, advanced control algorithms can be implemented to dynamically adjust the power transfer based on the alignment and position of the coils.

7.2. Infrastructure Development

Infrastructure development poses another major challenge and limitation for DWPT systems. Implementing in-motion DWPT systems on a large scale necessitates significant investment in infrastructure. This infrastructure encompasses the installation of coils, control systems, and power electronics on roadways, which is a process that can be costly and time consuming. Additionally, the installation process may disrupt traffic flow and necessitate road closures, inconveniencing commuters. Furthermore, constructing and embedding e-roadways involves significant planning and design considerations, including road surface materials, drainage, and maintenance requirements. This poses a challenge for deploying DWPT systems on existing roadways, as retrofitting existing infrastructure can be challenging and expensive. Another infrastructure development challenge is the standardization and interoperability of DWPT systems. As previously mentioned, different DWPT systems may utilize various frequencies, power levels, and coil geometries, complicating interoperability between different systems. This can lead to increased costs and complexity for system integration and maintenance. Overall, infrastructure development for DWPT systems presents a significant challenge and limitation that necessitates careful planning, design, and investment to overcome.

7.3. Power Coil Interoperability

One challenge in DWPT is achieving interoperability between different power coil systems. Since various manufacturers may utilize different coil designs, frequencies, and power levels, ensuring that a vehicle equipped with one type of power coil can utilize any DWPT infrastructure it encounters can be challenging. This could result in a fragmented market with incompatible systems, hindering the widespread adoption of DWPT technology. Another challenge is the necessity for the standardization of power coil dimensions and placement. This is crucial to ensure that vehicles can align with the power coils and achieve efficient power transfer. Standardization can also help decrease the cost of infrastructure development as well as vehicle manufacturing. Embedding power coils into existing infrastructure can be costly and time-consuming, often requiring extensive planning and coordination with local authorities. Additionally, the power grid may need upgrades to support the additional power demands of DWPT infrastructure, further complicating and increasing deployment costs.

7.4. Grid and Renewable Integration

The integration of DWPT systems with the power grid and renewable energy sources presents several challenges and limitations. One challenge is the need for efficient and reliable power conversion and conditioning systems to ensure that the power from the DWPT system can be integrated into the grid or used to charge EVs [97] without causing disruptions or instability in the power system. This requires the careful design and control of the power electronics to minimize power losses and ensure compatibility with different types of grid systems and renewable energy sources. Another challenge is the need for the coordination and management of the DWPT systems with the grid and renewable energy sources. This involves developing communication protocols and control strategies to ensure that the power transfer from the DWPT system does not conflict with the operation of the grid or the renewable energy sources. This includes managing the timing and location of power transfer to avoid overloading the grid or causing fluctuations in the power supply. The integration of DWPT systems with the grid and renewable energy sources requires careful consideration of the environmental and social impacts. This includes assessing the potential impacts on wildlife and ecosystems as well as addressing any concerns related to the visual or noise impacts of the DWPT infrastructure on nearby communities. Overall, the integration of DWPT systems with the grid and renewable energy sources presents both technical and social challenges that need to be addressed through careful planning, coordination, and stakeholder engagement.

7.5. Resonance and Compensation

Resonance and compensation are important factors to consider in DWPT systems as they can greatly affect the efficiency of power transfer. One challenge is designing the compensation network architecture to maintain resonance under varying load conditions and prevent any instability. This is especially important for in-motion DWPT systems, where the lateral misalignment between the Tx and Rx coils can affect resonance. The resonant frequencies of the Tx and Rx coils are compatible, especially for interoperability between different DWPT systems. The resonant frequency of the Tx and Rx coils should match, and the Q factor should be high to achieve efficient power transfer. Furthermore, resonance can cause interference with other electronic devices, which may cause health and safety concerns. Therefore, it is important to carefully design and test DWPT systems to ensure safe operation without causing harmful interference.

7.6. Safety and Health

Ensuring safety and addressing health concerns is one of the most significant challenges and limitations of dynamic wireless power transfer (DWPT) systems. High-frequency electromagnetic fields generated by the system can impact human health and safety, potentially leading to issues such as tissue damage, burns, and other health risks. Therefore, the design and operation of the DWPT system must carefully consider the safety limits of electromagnetic radiation exposure. It is crucial to establish international standards to ensure that the electromagnetic fields generated by the system remain within safe limits. Moreover, the design of the DWPT system should prioritize the safety and security of pedestrians, animals, and other objects that may come into contact with the system. The installation of ground-side coils or the e-roadway system should not pose any risks to pedestrians or animals. Additionally, the DWPT system should incorporate built-in safety features such as automatic power cutoff in the event of any malfunction or accident. Another safety concern is the risk of electric shock to occupants of EVs. The design of the DWPT system should include proper insulation and grounding measures to minimize this risk. EVs should also feature fail-safe mechanisms to ensure that the system shuts down in the event of electrical faults or emergencies. Overall, safety and health considerations are critical challenges and limitations of DWPT systems that must be addressed to ensure the widespread adoption of this technology. The system design should take into account safety limits for electromagnetic radiation exposure, pedestrian and animal safety, and the risk of electric shock to EV occupants.

7.7. Simultaneous Power and Communication

Simultaneous power and communication present another challenge in DWPT systems. Typically, communication and power transfer functions are handled by separate systems or modules. However, in a DWPT system, both communication signals and power are transmitted through the same channel, leading to potential interference that can affect the performance of both functions. To tackle this challenge, researchers have proposed various solutions. These include utilizing separate frequency bands for power and communication, implementing time-division multiplexing to segregate power and communication signals, and employing advanced modulation techniques capable of distinguishing between power and communication signals. Nevertheless, addressing the simultaneous power and communication challenge remains an ongoing area of research and development. Further investigations are necessary to comprehensively resolve this issue in DWPT systems.

7.8. Shielding Material Challenges

One of the challenges and limitations of dynamic wireless power transfer (DWPT) systems is associated with the shielding materials used to mitigate electromagnetic interference (EMI) and ensure safety. These materials play a crucial role in safeguarding sensitive electronics from interference and in averting the emission of high-frequency electromagnetic fields, which could pose health risks to humans and animals. However, employing shielding materials can also diminish the efficiency of the DWPT system by absorbing some of the magnetic fields utilized for power transfer. Additionally, these materials may contribute to the increased weight and bulkiness of the system, posing challenges during installation and operation, particularly in mobile applications such as electric vehicles. Therefore, DWPT system designers face the challenge of striking a balance between utilizing effective shielding materials to guarantee safety and minimize EMI, while also aiming to maintain high efficiency and reduce system weight and size. Current research endeavors focus on developing innovative shielding materials capable of efficiently reducing EMI and ensuring safety, all while preserving high efficiency and decreasing the weight and size of the system.

7.9. Performance of WPT System

There is a trade-off between the effectiveness of both functions when using the same transmission channel for power and data transfer. Ensuring stability in power flow and optimizing antenna circuits are essential for achieving effective resonance coupling. However, increasing data transfer leads to wider bandwidths, less stable power flow, and higher harmonic emissions, thereby reducing the effectiveness of wireless power transfer (WPT). The operating distance, which is influenced by the duration of data and energy transmission, the data rate, and the amount of transmitted energy, all represent trade-offs associated with the use of amplitude modulation. To address this issue, other modulation techniques such as phase-shift keying or frequency-shift keying are employed, allowing for a constant envelope. However, these techniques require more complex architectural designs.

7.10. Maximum Power Transfer Efficiency

The maximum power transfer efficiency (MPTE) in WPT systems is influenced by various factors, including the alignment of the transmitting and receiving coils, the distance between them, the system resonant frequency, and the efficiency of the power electronics. High PTE is crucial for efficient energy transfer between the transmitter and receiver, particularly for practical applications like electric vehicle charging. However, there are several challenges and limitations associated with achieving MPTE in DWPT systems. One major challenge is the lateral misalignment of coils during in-motion charging, which can reduce coupling and MPTE. Additionally, nearby metallic objects such as buildings and vehicles can interfere with coupling, leading to significant power losses. Moreover, high-power and high-frequency operational topologies in DWPT systems can increase losses due to the skin effect and eddy currents. Careful selection of the resonant frequency is also essential for maximizing power transfer efficiency. Another challenge is the need for a compensation network to optimize power transfer efficiency in non-ideal scenarios. This network must be designed to mitigate reactive components like inductance and capacitance, which can cause power losses and reduced efficiency. In summary, achieving MPTE in DWPT systems demands the meticulous design and optimization of system components, along with addressing challenges related to coil alignment, metallic objects, and compensation network design.

7.11. Miniaturization

Miniaturization poses a significant challenge and limitation for DWPT systems. The size of coils and electronics in a WPT system can impact its efficiency and suitability for specific applications. Smaller coils may not transfer as much power, while larger coils may be impractical for certain vehicles or devices. Additionally, miniaturization can lead to heat dissipation issues, as smaller components may generate more heat per unit area. One solution to this challenge is the use of high-frequency resonant circuits, which can reduce the size of coils and electronics while maintaining high efficiency. However, this approach requires careful tuning and design to ensure optimal performance. Another option is the utilization of multi-coil systems, offering greater flexibility in coil size and placement, although they may introduce complexity and cost. In conclusion, miniaturization is a critical consideration in DWPT system design, necessitating a balance between size, efficiency, and practicality across different applications.

7.12. Regulation and Limitation of WPT

In addition to frequency regulations, safety regulations must also be considered. Specifically, specific absorption rate (SAR) limits must be adhered to, ensuring that transmitted power does not harm human tissue. SAR limits are established by government agencies and vary based on the frequency range, power level, and exposure time. It is important to note that SAR limits are based on average power levels and do not consider peak power levels, which can occur in WPT systems. Another regulatory challenge for WPT is compatibility with other electronic devices. WPT systems can generate electromagnetic interference (EMI), which may disrupt the operation of other devices. Therefore, WPT systems must comply with EMI regulations to prevent interference with other electronic devices. Lastly, there are limitations to the maximum power transmitted via WPT. As the gap between the transmitter and receiver increases, efficiency declines, and losses due to environmental factors like absorption and reflection increase. Therefore, it is crucial to meticulously design WPT systems to meet both regulatory and performance standards.

7.13. Data Security

Data security is a significant concern in any wireless communication system, including DWPT. One of the main challenges in DWPT regarding data security is the risk of unauthorized access to transmitted data. Since the same channel is used for both power and data transmission, ensuring the confidentiality and integrity of the data becomes difficult. Moreover, since power transmission is conducted through magnetic fields, it is vulnerable to interference and can be easily intercepted by a third party. To address these challenges, various techniques have been proposed, including encryption and authentication protocols. One widely used technique is the Advanced Encryption Standard (AES), which provides a high level of protection against unauthorized access to data. Additionally, the use of secure communication protocols, such as SSL and TLS, can help ensure data security. To mitigate the risk of EMI, proper shielding and filtering techniques must be employed to reduce the impact of external electromagnetic fields. Moreover, careful frequency planning and management can help avoid interference from other wireless communication systems. Additionally, using spread spectrum techniques can help minimize the impact of interference on data transmission. DWPT faces several challenges related to data security, including the risk of unauthorized access and electromagnetic interference. To address these challenges, various techniques, including encryption, authentication, shielding, filtering, frequency planning, and spread spectrum techniques, can be employed.

7.14. Future Paths for Research

The DWPT technology can be further enhanced by pursuing the following research avenues:

• Creating more complex control algorithms that can adapt dynamically to changing circumstances and instantly maximize power transfer effectiveness. This involves utilizing artificial intelligence and machine learning together to anticipate and react to modifications in the charging environment.
• Research into cutting-edge techniques for keeping an eye on and optimizing the efficiency of power transfer. To continuously improve system performance, this may entail utilizing adaptive control methods and real-time data analytics.
• Investigation of innovative magnetic coupler arrangements that can improve the DWPT systems’ alignment tolerance and power transmission capacities. In order to lower losses and boost overall efficiency, this includes researching novel materials and geometric shapes.
• Research on novel designs and materials for compensating capacitors that can offer improved performance under dynamic loading circumstances is known as compensating capacitance innovation. This entails validating suggested solutions through experiments as well as theoretical modeling.
• To guarantee interoperability and ease of adoption, efforts are being made to integrate DWPT systems with the current EV infrastructure and standardize protocols. This entails working together with regulatory agencies and industry participants to create and execute thorough standards.
• Ongoing assessment of the socio-economic effects of DWPT technology, with an emphasis on policy frameworks, public acceptance, and cost–benefit analysis. The goal of this study should be to offer practical suggestions to industry executives and legislators to encourage the long-term growth of DWPT infrastructure.
• Lifecycle assessments and sustainability analysis are used to examine how DWPT systems affect the environment. The goal of this research is to find ways to reduce the environmental impact of DWPT technology and encourage its use as a more environmentally friendly charging method than traditional ones.

The DWPT community can keep pushing the envelope of what is feasible by focusing on these research areas. This will spur innovation and make sure that this promising technology can be successfully and sustainably incorporated into EV charging in the future.

8. Conclusion

EV charging has a lot of promise going forward because of DWPT technology, which removes the requirement for physical connections between EVs and charging stations. Enhancing power transmission efficiency is still a significant task, though, and researchers are always trying to find solutions. Improvements in power electronic circuits, magnetic coupler designs, compensatory capacitance, and control strategies are just a few of the solutions that have been investigated to increase efficiency. With regard to controller design and efficiency tracking for DWPT systems, this thorough review has filled a significant gap in the literature. We have mapped the field of DWPT research and highlighted important contributions and trends by offering a thorough bibliometric analysis. The examination of design processes and control strategies has illuminated cutting-edge methods and best practices for increasing power transfer efficiency today. Additionally, the socio-economic research has shed light on the DWPT technology’s broader ramifications, such as how it might affect the development of infrastructure, the adoption of EVs, and market dynamics.