Search Results (94)

The wireless charging of electric vehicles (EVs) has drawn much attention as it can ease the charging process under different charging situations and environmental conditions. However, power transfer rate and efficiency are the critical parameters for the wide adaptation of wireless charging systems. Different investigations are presented in the literature that have aimed to improve power transfer efficiency and to maintain constant power at the load side. This paper introduces a Maximum Efficiency Point Tracking (MEPT) system designed specifically for a reconfigurable S-LCC compensated wireless charging system. The reconfigurable nature of the S-LCC system supports the constant current (CC) and constant voltage (CV) mode of operation by operating S-LCC and S-SP mode. The proposed system enhances power transfer efficiency under load fluctuations, coil misalignments, and a wide range of operating conditions. The developed S-LCC compensated system inherently maintains the power transfer rate constantly under a majority of load variations. Meanwhile, the inclusion of the MEPT method with the S-LCC system provides stable and maximum output under different coupling and load variations. The proposed MEPT approach uses a feedback mechanism to track and maintain the maximum efficiency point by iteratively adjusting the DC-DC converter duty ratio and by monitoring load power. The proposed approach was designed and tested in a 3.3 kW laboratory scale prototype module at an operating frequency of 85 kHz. The simulation and hardware results show that the developed system provides stable maximum power under a wider range of load and coupling variations. Full article

To address the limitations of conventional magnetically coupled resonant wireless power transfer (MCR-WPT) systems in multi-frequency multi-load applications—specifically inadequate load power independence and high complexity inconstant-voltage/constant-current (CV/CC) control—this paper proposes a variable-structure dual-frequency dual-load wireless power transfer system by first establishing its mathematical model and implementing hybrid-frequency modulation for multi-frequency output, then developing an improved T/LCC hybrid resonant topology by deriving parameter design conditions for compensation network reconfiguration under CV/CC requirements, subsequently employing an orthogonal planar solenoid coupling mechanism and frequency-division demodulation to achieve load-independent power regulation across wide load ranges for enhanced stability, and finally constructing a 120 W dual-frequency dual-load prototype to validate the system’s CV/CC characteristics, where simulations and experimental results demonstrate stronger consistency with theoretical predictions. Full article

Dynamic wireless charging systems have emerged as a promising solution to extend the driving range of electric vehicles by enabling energy transfer while the vehicle is in motion. However, the segment-based charging lane structure introduces challenges such as pulsation of the output power and the need for precise switching control of the transmitting segments. This paper proposes a position-sensorless control method for managing transmitting lines in a dynamic wireless charging system. The proposed approach uses a segmented charging lane structure combined with two receiving coils and LCC compensation circuits on both the transmitting and receiving sides. Based on theoretical analysis, the study determines the optimal switching positions and signals to reduce the current fluctuation. To validate the proposed method, a dynamic wireless charging system prototype with a power rating of $3kW$ was designed, constructed, and tested in a laboratory environment. The results demonstrate that the proposed position-sensorless control method effectively mitigates power fluctuations and enhances the stability and efficiency of the wireless charging process. Full article

Wireless power transfer systems require not only strong coupling capabilities but also stable output under various misalignment conditions. This paper proposes a hybrid magnetic coupler for autonomous underwater vehicles (AUVs), featuring two identical arc-shaped rectangular transmitting coils and a combination of an arc-shaped rectangular receiving coil and two anti-series connected solenoid coils. The arc-shaped rectangular receiving coil captures the magnetic flux generated by the transmitting coil, which is directed toward the center, while the solenoid coils capture the axial magnetic flux generated by the transmitting coil. The parameters of the proposed magnetic coupler have been optimized to enhance the coupling coefficient and improve the system’s tolerance to misalignments. To verify the feasibility of the proposed magnetic coupler, a 300 W prototype with LCC-S compensation topology is built. Within a 360° rotational misalignment range, the system’s output power maintains around 300 W, with a stable power transmission efficiency of over 92.14%. When axial misalignment of 40 mm occurs, the minimum output power is 282.8 W, and the minimum power transmission efficiency is 91.6%. Full article

To address the challenge of a conventional line-commutated converter (LCC), unable to operate properly in connection with a very weak AC system, the technology of the capacitor-commutated converter (CCC) was widely utilized in 1990s. The topology of the CCC is constructed as a conventional LCC modified with a series capacitor between the converter transformer and the thyristor valves in each phase. Additional phase voltage can be generated on the capacitor to assist the process of the commutation. However, the CCC technology may experience continuous commutation failure due to the uncontrolled charging of the series capacitor. Based on the submodule-cascaded static synchronous compensator (STATCOM), this paper proposes a novel topology called the submodule-cascaded STATCOM-based CCC (SCCC). The SCCC technology enables the function of reactive power compensation and active filtering. It can also improve the transient characteristics of the AC faults via dynamic reactive power injection during the transient process, which helps to reduce the risk of continuous commutation failure in the CCC. Full article

This study presents the development, simulation, and hardware implementation of a 48 V, 1 kW mid-range wireless power transfer (WPT) platform for autonomous guided vehicle (AGV) charging in industrial applications. The system uses an LCC-S compensation topology, selected for its ability to maintain a constant output voltage and deliver high efficiency even under load variations at a typical coil distance of 15 cm. It can also operate at different distances by adjusting the compensator circuit. A proportional–integral (PI) controller is implemented for current regulation, offering a practical, low-cost solution well suited to industrial embedded systems. Compared to advanced control strategies, the PI controller provides sufficient accuracy with minimal computational demand, enabling reliable operation in real-world environments. Current adjustment can be dynamically carried out in response to real-time changes and continuously monitored based on the AGV battery’s state of charge (SOC). Simulation and experimental results validate the system’s performance, achieving over 80% efficiency and demonstrating its feasibility for scalable, robust AGV charging in Industry 4.0 Manufacturing Settings. Full article

In the context of vehicle-to-grid (V2G) applications, single-port bidirectional inductive power transfer (BDIPT) systems have difficulty coping with the growing demand for electric vehicles. This paper proposes a multi-port BDIPT system based on an LCC-LCC compensation network. A multi-phase-shift (MPS) control with more degrees of freedom is proposed, where the external phase shift angle controls the power transmission direction and the internal phase shift angle controls the transmitted power magnitude. Independent multi-port operation for the multi-port BDIPT system can be achieved. Finally, the theoretical results are verified by experiments. The experimental results show that the LCC-LCC-based multi-port BDIPT system can achieve independent control of the transmission power at each port. Full article

Wireless power transfer (WPT) is recognized as a critical technology to advance carbon neutrality in transportation by alleviating charging challenges for electric vehicles and accelerating their adoption to replace fossil fuel. To ensure durability under traffic loads and harsh environments while avoiding vehicle obstructions, WPT primary circuits should be embedded within pavement structures rather than surface-mounted. This study systematically investigated the optimization of magnetite-modified asphalt material composition and thickness for enhancing electromagnetic coupling in WPT systems through integrated numerical and experimental approaches. A 3D finite element model (FEM) and a WPT platform with primary-side inductor–capacitor–capacitor (LCC) and secondary-side series (S) compensation were developed to assess the electromagnetic performance of magnetite content ranging from 0 to 25% and pavement thickness ranging from 30 to 70 mm. Results indicate that magnetite incorporation increased efficiency from 80.3 to 84.7% and coupling coefficients from 0.236 to 0.242, with power loss increasing by only 0.25 W. This enhancement is driven by improved equivalent permeability, which directly enhances magnetic coupling efficiency. A critical pavement thickness of 50 mm was identified, beyond which the reduction in transmission efficiency increased significantly due to magnetic flux dispersion. Additionally, the nonlinear increase in power loss is partially attributed to the significant rise in hysteresis and eddy current losses at elevated magnetite content levels. The proposed design framework, which focuses on 10% magnetite content and a total pavement thickness of 50 mm, achieves an optimal energy transfer efficiency. This approach contributes to sustainable infrastructure development for wireless charging applications. Full article

This study proposes an optimal resonant network design for an 11.1 kW wireless power transfer (WPT) system with a double-sided LCC compensation circuit, targeting 800 V class battery applications. Conventional WPT circuit topologies and design parameters specified in existing standards, such as SAE J2954, are unsuitable for 800 V class battery systems because they impose excessive voltage and current stresses on the resonant network components. To address this, the proposed design focuses on minimizing component stresses while ensuring compliance with the output voltage requirements for 800 V battery charging. A switched capacitor technique is integrated into the resonant network to dynamically adjust the compensation capacitance, enabling seamless adaptation to the constant current–constant voltage charging profile. The feasibility of the WPT system is validated through simulations and experiments, demonstrating an input voltage of 400 VDC, an output voltage range of 560–820 VDC, and a rated power capacity of 11.1 kW. Under rated conditions, the system achieves a peak efficiency of 95%, underscoring its practicality for high-voltage electric vehicle charging applications. Full article

For the double-sided inductor–capacitor–capacitor (DS-LCC) compensation topology, the parametric deviation of compensation elements results in the mismatch between the resonant frequency and operating frequency. Furthermore, this mismatch leads to the loss of the load-independent constant output characteristics. Therefore, an innovative design approach based on the reduction in the capacitance ratio is proposed to attain the load-independent constant current under the parametric deviation. With the presented method, simply by reducing the compensation capacitor ratio, the load-independent constant current output characteristics can be preserved, and fluctuations in the transmission gain caused by the parametric deviation are minimized. This implies that when the constant transmission gain is achieved by the frequency modulation (FM) control, the required FM range can be reduced. Finally, from the experimental results, in the load range of 3 Ω to 33 Ω, compared to the high capacitance ratio, the load-independent constant current characteristics can be maintained at the low capacitance ratio. In addition, without parametric deviation, the transmission efficiencies at different capacitance ratios are basically the same at 93.5% and 94.2%, respectively. However, the transmission efficiencies under different parametric deviations at the low capacitance ratio are 87.4% and 84.9%, but only 73.9% and 68.2% at the high capacitance ratio. Full article

This paper proposes a combined maximum efficiency tracking and improved active disturbance rejection control (ADRC) strategy for an inductive power transfer (IPT) system, addressing issues of reduced efficiency and voltage fluctuations under load variations. The transmission characteristics of the inductor–capacitor–capacitor and series (LCC-S) IPT system are analyzed, and the relationship between transmission efficiency and the secondary DC-DC converter’s duty cycle is derived. Maximum efficiency tracking is achieved by adjusting the secondary converter’s duty cycle via the primary side Buck converter. An improved ADRC controller enhances dynamic voltage regulation by reducing the extended state observer’s order and incorporating model information for better disturbance compensation. Experimental results show that the proposed approach improves average transmission efficiency by 12% and maintains constant output voltage under varying loads. The controller requires fewer parameters than linear active disturbance rejection control (LADRC), with faster responses and smaller voltage fluctuations than PI and LADRC controllers. Full article

In multi-load wireless power transfer (WPT) systems, when multiple loads simultaneously charge using the same transmitter, the unpredictable spatial positions of the loads and the presence of cross-coupling make it challenging to achieve complete system decoupling, thereby limiting the effective power reception area. To address this issue, this paper investigates a one-to-multiple WPT system based on a single-transistor P^#-type LCC-S compensation network. Air-core coils are employed at the receiving end to mitigate cross-coupling, and the effective power reception area is analyzed. First, the operating principle of the system is examined and the parameter configuration conditions for the resonant circuit are derived. Then, MATLAB/Simulink R2022b is used to establish simulation circuit models for both single-transmitter single-receiver and single-transmitter dual-receiver WPT systems. The results indicate that for an effective output power of 5 W, the mutual inductance ranges are (3.5, 6) μH and (3, 6.5) μH, respectively. Next, finite element simulations are conducted to analyze the mutual inductance variations caused by spatial misalignment of the coils. For the single-transmitter single-receiver system, when the transmission distance is 5–12.5 mm, the effective power reception area corresponds to an X- and Y-axis misalignment of ±15 mm, while at a transmission distance of 10 mm, the effective reception area is ±10 mm along both axes. In the single-transmitter dual-receiver system, for a transmission distance of 5–14 mm, the maximum reception area is ±15 mm along the X-axis and ±10 mm along the Y-axis. Finally, an experimental platform is built to verify that multiple loads at different positions can achieve effective power reception for charging. Full article

This study was conducted to achieve simple and feasible secondary-side independent power control for wireless power transfer (WPT) systems with a hybrid energy storage system (HESS) and to minimize the power loss introduced by the added converter. We propose a novel operation mode tailored to a WPT system with a HESS load composed of an LCC-compensated WPT system and a Buck/Boost bidirectional converter. Its power control is based on insights into the characteristics of LCC–LCC compensation. Since this control method requires the cooperation of a DC converter, control of the converter’s efficiency is the focus of this paper. Building on this framework, several parasitic parameters such as the equivalent series resistance (ESR) of inductors and switches are taken into account. An improved operation mode is proposed to address the efficiency degradation and control imbalance caused by ESR. By meticulously controlling the behavior of the components of the converter, the devices operate in zero-voltage switching (ZVS) mode, thereby reducing switching losses. Additionally, fuzzy control is utilized in this study to enhance robustness. The analyses are verified through a prototype system. The results of the experiments illustrate that the analytical approach proposed in this study achieves reliable power control and efficient converter operation. The results of this study show that the efficiency of the devices is improved and reached up to 99% with the converter. This study explores the efficiency optimization of the WPT system, which directly supports sustainable practices by reducing resource consumption and minimizing environmental impact. The findings offer valuable insights into sustainable applications and policy implications, aligning with the goals of socio-economic and environmental sustainability. Full article

The integration of inductive charging technology in electric vehicles has aroused the interest of researchers in recent years. Specifically, one of the growing areas is wireless charging in Autonomous Underwater Vehicles (AUVs). In this environment, the effects of seawater in wireless power transmission should be carefully studied. Specifically, one of the effects that should be analysed is the appearance of parasitic capacitances ($C_e$) between the power coils due to the high conductivity of seawater. The parasitic capacitance, together with the power converters switching losses and the resistive and inductive losses, can lead to a drop in efficiency during the charging process. The main objective of this contribution is to find the optimal solution to avoid the effects of $C_e$ during the coils design, thus simplifying the process and making it equivalent to an air-based solution. To do so, different design criteria have been defined with a comparative analysis among different topologies proposed. Specifically, we have studied the variations of voltage, current, and efficiency caused by the $C_e$. Additionally, a comparison between Series-Series (SS) and LCC–Series (LCC–S) compensation systems has been considered, studying the system efficiency and maximum current values found on the circuit. The results of these studies have been verified through experimental validations, where the design and implementation of the elements that constitute the inductive charger have been performed. This validation has demonstrated the possibility of neglecting the effects of $C_e$ by optimising the coil’s design. Full article

This study presents the design, analysis, and experimental validation of a 500 W inductive power transfer (IPT) system with a transmission distance of 250 mm for television applications. The proposed system incorporates an innovative wireless pad design featuring a four-teeth magnetic structure and an LCC-S compensation topology to optimize coupling coefficients, reduce copper losses, and improve overall efficiency. The system’s robustness under misalignment and load fluctuations was validated, with experimental results confirming over 80% efficiency for optimal configurations. The findings also highlight the sensitivity of the system to switching frequency variations, emphasizing the need to maintain resonance conditions for maximum power transfer. Compared to existing designs, the proposed system demonstrates superior performance in long-distance wireless power transfer, making it a promising solution for high-power applications in home appliances. Full article