Search Results (2,297)

To enhance the battery endurance of unmanned aerial vehicles (UAVs), this article addresses key issues in traditional wireless power transfer (WPT) systems. These issues occur during constant current/constant voltage (CC/CV) switching, such as poor stability, high payload, power loss, and charging instability. Accordingly, a WPT system based on topology switching is proposed. First, a lightweight compensation topology based on LCC-Series compensated topology (LCC-S) is designed. A tuning capacitor is incorporated, and two switches regulate the switching of the compensation capacitor to realize CC/CV mode transition. Meanwhile, the impedance matrix model is built to find optimal compensation component values, maximizing energy transfer. To reduce sensitivity to misalignment, a “+” shaped compensation coil is added to the basic 2 × 2 square coil array. It improves magnetic field uniformity and suppresses flux leakage. Experimental results show that the system achieves stable load-independent output. Within horizontal offset [−150, 150] mm and diagonal offset [−150√2, 150√2] mm, it keeps output power over 150 W and efficiency over 70%, with strong anti-misalignment ability. This system effectively solves key challenges such as endurance bottlenecks, complex CC/CV switching, and weak anti-misalignment. It offers a reliable technical solution for efficient charging of autonomous UAVs. Full article

Electric vehicles (EVs) are experiencing rapid global adoption driven by environmental concerns and fuel security. This article presents a new dual-source converter based on a hybrid modular multilevel configuration (DCHMMC) designed for optimal cell utilisation in EV battery systems. Contrary to conventional converters that can either charge or discharge the cells using a single source, thereby leaving several cells/modules (Ms) idle during each time step, the proposed converter enables the integration of two sources that can utilise the cells simultaneously. This dual source feature minimises idle cells/Ms, enhances energy efficiency, and supports flexible bidirectional power flow. The proposed converter operates in three distinct modes. The first involves dual-source charging for fast charging and improved vehicle availability. The second involves one source charging while the other discharges for dynamic operation. Finally, the last involves dual-source discharging for maximum power delivery and support vehicle-to-grid (V2G) operation. The simulation results demonstrated smooth multilevel sinusoidal output voltages (Vout_a and Vout_b), each with a peak of 350 V, generated simultaneously using 132 cells (six cells per M, 22 Ms). The total harmonic distortion (THD) values for Vout_a and Vout_b were 0.42% and 2.25%, respectively, confirming the high-quality performance. Furthermore, only 0–36 cells and 0–6 Ms were idle during operation, showing improved cell utilisation. Full article

This paper presents a robust control strategy for three-phase inverters that combines Sliding Mode Control with a Washout Filter (SMC-w) to achieve low harmonic distortion and high dynamic stability. The proposed approach addresses the critical challenge of maintaining the stability of a high-quality output signal while ensuring robustness against disturbances and adaptability under variable, unbalanced, and nonlinear loads. The proposed hybrid controller integrates the fast response and disturbance rejection capability of SMC with the filtering properties of the washout stage, effectively mitigating low-frequency chattering and steady-state offsets. A detailed stability analysis is provided to ensure the closed-loop convergence of the SMC–w. Simulation results obtained in MATLAB–Simulink demonstrate significant improvements in transient response, total harmonic distortion, and robustness under unbalanced and nonlinear load conditions compared to conventional control methods. The inverter demonstrated rapid tracking of the reference signals with a minimal error margin of 3%, effective frequency regulation with a low steady-state error, and resilience to input disturbances and load variations. For instance, under a load variation from 20 Ω to 5 Ω, the system maintained the output voltage accuracy within a 3% error threshold. In addition, the input perturbations and frequency shifts in the reference signals were effectively rejected, confirming the robustness of the control strategy. Furthermore, the integration of the SMC proved to be highly effective in reducing harmonic distortion and delivering a stable and high-quality sinusoidal output. The integration of the washout filter minimized the chattering phenomenon typically associated with the SMC, further enhancing the smooth response and reliability of the system. This study highlights the potential of SMC–w to optimize power quality and operational stability. This study offers significant insights into the development of advanced inverter systems that can operate in dynamic and challenging environments. Full article

Aiming to address the insulation and power supply challenges faced by electrical measurement in ultra-high voltage (UHV) environments, this study proposes and implements a nitrogen-vacancy (NV) center magnetic sensing system based on Power over Fiber (PoF) technology. The system adopts a high-voltage and low-voltage separation design, realizing the isolated transmission of electrical energy and the reliable recovery of measurement signals through an optical fiber link. The sensing unit on the high-voltage side is composed of NV center sensors, microwave excitation modules, and signal processing modules. Its power supply is provided by an independently developed high-power laser power converter (LPC) assembly via 830 nm optical fiber laser transmission. Under an optical input of 10 W, this assembly can achieve an electrical output of 4.88 W with a conversion efficiency of 48.9%. The experimental results show that the system can operate stably in a simulated UHV environment; by optimizing modulation parameters, the optimal magnetic measurement sensitivity reaches 6.1 nT/Hz^1/2. This research provides a safe and reliable solution for the power supply and precise sensing of high-potential side equipment in UHV scenarios, and demonstrates the application potential of PoF technology in advanced sensing for power systems. Full article

In response to the high energy consumption and carbon emission issues in the electrolytic aluminum industry, this paper proposes a multi-time-scale optimization and control method for electrolytic aluminum plants with high photovoltaic penetration. First, a plant architecture is established, which includes traditional power systems, renewable energy systems, and electrolytic aluminum loads. A mathematical model for flexible resources such as thermal power units, on-load tap-changing transformers, thyristor-controlled voltage regulators, saturable reactors, and electrolytic cells is developed. Based on this, a two-level optimization control strategy is designed, consisting of a day-ahead and real-time control layer: the day-ahead layer targets economic and low-carbon operation, while the real-time layer aims to stabilize the DC bus voltage. Using actual data from an electrolytic aluminum plant in Southwest China, simulations are conducted on the MATLAB 2021a platform, and the effectiveness of the strategy is verified through hardware-in-the-loop experiments. The results demonstrate that the proposed method can effectively increase the photovoltaic utilization rate, reduce thermal power output and operational costs, and decrease carbon emissions, providing a feasible solution for the green and low-carbon transformation of the electrolytic aluminum industry. Full article

For the application of a high-performance shortwave infrared (SWIR) detector, a fully integrated analog front-end (AFE) circuit is proposed in this paper, which includes a readout integrated circuit (ROIC) and a 12-bit/100 kHz two-step single-slope analog-to-digital converter (TS-SS ADC). The ROIC adopts a direct injection (DI) structure with a pixel size of only 10 µm × 10 µm. The column processing circuit uses a passive correlated double-sampling (CDS) circuit to reduce noise and improve dynamic range. The comparator of four inputs in the ADC solves the problem of linearity reduction caused by charge redistribution during coarse quantization. In addition, the current steering digital-to-analog converter (DAC) is used to compensate for the non-ideal characteristics of the switch, which effectively optimizes the differential nonlinearity (DNL) and integral nonlinearity (INL). The AFE is implemented using SMIC 180 nm 1P6M technology. The post-simulation results show that at a power supply voltage of 3.3 V, the AFE has a frame rate of 100 Hz and a full well capacity (FWC) of 2.8 Me⁻. The linearity can reach 99.59%, and the equivalent output noise is 243 µV. The dynamic range is 73.8 dB. Meanwhile, the signal-to-noise distortion ratio (SNDR) and effective number of bits (ENOB) are 68.38 dB and 11.06 bits, respectively. Full article

Electric vehicles (EVs) powered by lithium-ion batteries are crucial for sustainable transportation. Accurate State of Charge (SOC) estimation, a core function of Battery Management Systems (BMS), enhances battery performance, lifespan, and safety. This paper proposes a hybrid CNN-LSTM-AKF model integrating Convolutional Neural Networks (CNN) and Long Short-Term Memory (LSTM) Neural Networks with an Adaptive Kalman Filter. CNN extracts spatial features from current, voltage, and temperature data, while LSTM processes temporal dependencies. AKF reduces output fluctuations. Trained on datasets under three operating conditions, the model was tested across various temperatures and initial SOC states. Results demonstrate that the proposed model significantly outperforms standalone LSTM and LSTM-AKF model, particularly at low temperatures. Within 0 °C to 50 °C, it achieves Root Mean Square Error (RMSE) and Mean Absolute Error (MAE) below 1.51% and 1.18%, respectively. With an initial SOC of 80%, the model achieves an RMSE of 1.09% and MAE of 0.88%, showing rapid convergence. The model exhibits high accuracy, strong adaptability, and robust performance. Full article

Hydroelectricity energy harvesting has emerged as a promising, eco-friendly alternative for addressing the growing demand for sustainable energy solutions. In this study, we present a hydroelectricity energy harvester fabricated from shredded waste printing paper (WPP), offering a novel waste-to-energy conversion strategy that requires neither material purification nor complex processing. The device leverages the randomly entangled fiber network of WPP to facilitate capillary-driven moisture diffusion and electric double layer (EDL) formation, thereby enabling efficient electrokinetic energy conversion. The random arrangement of WPP fibers increases the effective EDL area, allowing the waste printing paper generator (WPPG) to achieve an open-circuit voltage of 0.372 V and a short-circuit current of 135 μA at room temperature under optimized electrolyte conditions. This study demonstrates that carbon-black-coated WPP can be effectively upcycled into a high-performance hydroelectricity generator, exhibiting excellent electrical output at ambient conditions. By combining material recycling with efficient energy conversion, this system establishes a practical and sustainable pathway for distributed power generation. Overall, this work not only presents an environmentally responsible approach to device fabrication but also highlights that hydroelectricity energy harvesting using WPPG represents a promising alternative energy route for future applications. Full article

A multiphysics-coupled 2–2 cement-based magnetoelectric composite model is established in COMSOL 6.2. This model is used to not only systematically investigate the magnetoelectric-coupling behavior, but also quantify the effects of the magnetic field, frequency, and layer-thickness ratio on the material’s magnetoelectric properties. The results demonstrate that the model effectively reproduces the internal stress–strain distribution and voltage evolution. Specifically, the magnetostrictive and piezoelectric layers exhibit mechanical responses with pronounced non-uniformity, which is attributed to boundary effects. The bias magnetic field plays a crucial regulatory role: the output voltage increases linearly from 0 to 2000 Oe and then saturates at higher fields. Under an alternating magnetic field, the composite exhibits pronounced resonance characteristics, whose frequency is jointly governed by structural dimensions and the bias field. The dynamic response was further analyzed using the magnetic flux density modulus, displacement profiles at selected locations, and voltage evolution across the piezoelectric layer. Notably, the thickness of each functional phase exerts a pronounced and distinct influence on the composite’s magnetoelectric coupling, with markedly different trends between phases. Optimization results show that a thin piezoelectric layer combined with a thick magnetostrictive layer yields the highest magnetoelectric performance. Additionally, the longitudinal and transverse magnetoelectric coefficients exhibit markedly different coupling mechanisms—this is owing to the misalignment between the magnetic-field and electric-polarization directions, and this difference further reveals the intrinsic anisotropy of the magnetoelectric response. Overall, this study provides a crucial theoretical foundation for the design and optimization of high-performance cement-based magnetoelectric composites. Full article

This paper introduces a new four-switch, high-voltage, high-step-up converter employing two transformers. The topology enables Zero-Voltage Switching (ZVS) across all primary switches for operating conditions ranging from no load to full load. A voltage-quadrupler and a voltage-doubler rectifier are used on the secondary sides of the transformers, enabling reduced turn-off current for the voltage-quadrupler diodes and Zero-Current Switching (ZCS) turn-off for the voltage-doubler diodes, thereby ensuring high efficiency across diverse load levels. Notably, the voltage stress experienced by the voltage-multiplier diodes is significantly lower than the output voltage, thereby rendering the converter exceptionally suitable for high-voltage applications such as electron beam welding (EBW). The voltage gain surpasses that of the conventional phase-shift full-bridge (PSFB) converter, permitting a lower transformer turns ratio and thus reducing winding resistivity. The removal of the substantial output inductor leads to a lighter and more compact design, eliminating insulation concerns associated with inductor windings. This paper details the operation of the proposed converter, supported by experimental results from a 500-W prototype with a 150-V input and 2-kV output, which confirm its high performance and operational advantages. Full article

Due to the diverse needs of users, such as the requirement for rapid charging in time-sensitive situations and the need to minimize battery power consumption to extend battery life when the device is idle, a wireless charging system that combines fast and slow charging capabilities is crucial for adapting to various usage scenarios. This paper proposes a multi-mode wireless charging system based on a reconfigurable transmitter, which can simultaneously charge different types of batteries with both fast and slow charging capabilities. By applying different control logic to the power devices in the reconfigurable inverter, the system can achieve four operating modes: two different constant current (CC) modes and two different constant voltage (CV) modes. Furthermore, the system can switch between these modes by configuring the MOSFETs operating states: two three-coil configurations are used for the two CC modes, while two two-coil configurations are used for the two CV modes. Therefore, the system exhibits high versatility. To verify the theoretical analysis of the proposed system, an experimental prototype with an output specification of 3 A/2.2 A/78 V/65 V is built. Full article

Temperature is a crucial indicator in monitoring industrial operations. Two-wire temperature transmitters, known for their precise measurements, are extensively used in sectors like crude oil extraction, refining, and fine chemicals. These transmitters can handle a maximum input voltage of 36 V and output a current signal up to 20 mA, enhancing resistance to electromagnetic interference and line noise while improving system compatibility and safety. In contrast, traditional low-dropout linear regulators (LDOs) typically have an input voltage below 6 V and suffer from limitations such as low power supply rejection ratio (PSRR), inadequate current driving capability, and significant temperature drift. This paper proposes a wide-input-range LDO with enhanced output accuracy and digital trimming, designed using the 180 nm BCD process. It incorporates dynamic mismatch compensation, digital trimming, and a strong-drive buffer, achieving a broad input voltage range and high PSRR with minimal temperature drift. The input voltage spans 6 V to 60 V, the output voltage is 1.8 V, and the PSRR reaches 124.5 dB. Across a temperature range of −40 °C to 130 °C, the maximum output voltage error is only 0.3%. This makes it highly suitable for high-precision circuit power supplies in industrial process control. Full article

This study presents a pulse generator employing a saturable pulse transformer (SPT) in conjunction with a fast recovery diode, integrated within an all-solid-state pulse-forming network (PFN). The saturation inductance of the SPT serves as a component of the initial LC section of the PFN, thereby contributing to the preservation of output waveform integrity. The secondary energy storage capacitor is charged through the primary circuit and the SPT, subsequently discharging into the load under the regulation of the SPT. An increase in the SPT’s transformation ratio corresponds to a rise in its saturated inductance, which in turn prolongs the pulse rise time. To mitigate this effect, a fast recovery diode is incorporated to sharpen the pulse front. Specifically, upon saturation of the SPT, current reverses through the fast recovery diode, effectively short-circuiting the load. When the inductor current attains a predetermined threshold, the diode reverts to reverse cut-off and rapidly switches off, enabling the PFN to discharge swiftly into the load and generate a high-voltage pulse characterized by a rapid rising edge. Furthermore, augmenting the number of secondary windings on the SPT—each connected to a PFN module—and arranging multiple PFNs in series facilitates an increase in output voltage. Experimental evaluations demonstrated that a three-stage PFN pulse generator attained a peak voltage of −16.9 kV on an 80 Ω matched load, with pulse currents exceeding 200 A while maintaining a 19 ns front edge. These results indicate that the proposed approach is effective for producing high-voltage, narrow pulses with rapid rise times. Additionally, the pulse power generator is capable of delivering repetitive pulses of −16.9 kV at a frequency of 20 kHz in burst mode. Full article

This work presents the development and experimental validation of a low-cost, piezoelectret-based energy harvesting system integrated into a custom insole, as a promising alternative for future self-powered wearable electronics. The design utilizes eight thermoformed Teflon piezoelectrets, strategically positioned in high-impact regions (heel and forefoot), to convert footstep-induced mechanical motion into electrical energy. The sensors, fabricated using Fluorinated Ethylene Propylene (FEP) and Polytetrafluoroethylene (PTFE) layers via thermal pressing and aluminum sputtering, were connected in parallel to enhance signal consistency and robustness. A solenoid-actuated mechanical test rig was developed to simulate human gait under controlled conditions. The system consistently produced voltage pulses with peaks up to 13 V and durations exceeding ms, even under limited-force loading (10 kgf). Signal analysis confirmed repeatable waveform characteristics, and a Delon voltage multiplier enabled partial conversion into usable DC output. While not yet optimized for maximum efficiency, the proposed setup demonstrates the feasibility of using piezoelectrets for energy harvesting. Its simplicity, scalability, and low cost support its potential for future integration in applications such as fitness tracking, health monitoring, and GPS ultimately contributing to the development of autonomous, self-powered smart footwear systems. It is important to emphasize that the present study is a proof-of-concept validated exclusively under controlled laboratory conditions using a mechanical gait simulator. Future work will address real-time insole application tests with human participants. Full article

Triboelectric nanogenerators (TENGs) have emerged as a promising technology for harvesting mechanical energy via contact electrification (CE) at diverse interfaces, including solid–liquid, liquid–liquid, and gas–liquid phases. This review systematically explores fluid-based TENGs (Flu-TENGs), introducing a foundational and novel classification framework based on direct versus indirect charge transfer to the charge-collecting electrode (CCE). This framework addresses a critical gap by providing the first unified analysis of charge transfer mechanisms across all major fluid interfaces, establishing a clear design principle for future device engineering. We comprehensively compare the underlying mechanisms and performance outcomes, revealing that direct charge transfer consistently delivers superior energy conversion—with specific studies achieving up to 11-fold higher current and 8.8-fold higher voltage in solid–liquid TENGs (SL-TENGs), 60-fold current and 3-fold voltage gains in liquid–liquid TENGs (LL-TENGs), and 34-fold current and 10-fold voltage enhancements in gas–liquid TENGs (GL-TENGs). Indirect mechanisms, relying on electrostatic induction, provide stable Alternating Current (AC) output ideal for low-power, long-term applications such as environmental sensors and wearable bioelectronics, while direct mechanisms enable high-efficiency Direct Current (DC) output suitable for energy-intensive systems including soft actuators and biomedical micro-pumps. This review highlights a paradigm shift in Flu-TENG design, where the deliberate selection of charge transfer pathways based on this framework can optimize energy harvesting and device performance across a broad spectrum of next-generation sensing, actuation, and micro-power systems. By bridging fundamental charge dynamics with application-driven engineering, this work provides actionable insights for advancing sustainable energy solutions and expanding the practical impact of TENG technology. Full article