To enhance the misalignment tolerance and system integration of the wireless power transfer (WPT) system, an integrated coupler consisting of capacitors and coils overlapped coaxially is proposed in this article and integrated into the hybrid WPT (HWPT) system without extra compensation components. The system utilizes the complementary characteristics of different transmission channels to realize the synergistic transfer of different coupled powers under a wide coupling range. Based on the mutual influence between capacitors and coils in terms of electrical parameters in a limited axial projection area and the zero-phase-angle condition considering the mutual capacitance obtained by the fundamental harmonics approximation method, the method of regulating the transfer ratio of the two types of coupled powers is mastered. A method to realize the HWPT with high misalignment tolerance characteristics by frequency tracking is proposed to solve the problem of the system's resonant state being disrupted when the position of the integrated coupler is misaligned. The field-circuit coupling model verifies the feasibility of the analysis and transfer method. Finally, an experimental verification platform for 500 W is built to achieve 82.7% power transfer in the WPT system with 40% unidirectional misalignment.

This article proposes a power relay system to wirelessly power multiple loads via capacitive coupling. The intermediate capacitive relay unit is designed to power the load as well as enhance the power transfer capability, which contains two receiving plates and two transmitting plates. It is proven in this article that the capacitive coupling between the receiving and transmitting plates in the same relay unit can be eliminated by being placed perpendicularly with the help of the proposed split-inductor-based compensation network. A general mathematical model of the multiload capacitive power relay system is established. The L compensation circuits are employed to compensate the first and the last relays, while the LCL compensation circuits are designed to compensate the intermediate relays. Thus, the constant current output can be obtained for each load without affecting each other when neglecting the parasitic resistances. Additionally, the load current and efficiency variations versus the load resistance, coupling coefficient, and quality factor are thoroughly analyzed. Finally, a three-load experimental prototype is constructed to verify the feasibility of the proposed multiload capacitive power transfer relay system. The maximum efficiency can reach 86.1% at a power level of 37 W.

Inductive-power-transfer (IPT) is widely used in wireless charging of electric vehicle (EV). However, the output power and efficiency of the IPT system are often affected by misalignments. In this paper, a double-side-LCC (DLCC) compensation network with switch-controlled-capacitors (SCC) IPT topology is proposed to improve the misalignments tolerance for EV. First of all, the output power models of DLCC-SCC IPT system under tuned and detuned conditions are derived. Secondly, the best choice of selecting adjustable capacitors for regulating the output power is analyzed. Then, an optimal control strategy for DLCC-SCC IPT system that maintains constant-power (CP) output and zero-phase-angle (ZPA) under large misalignments is designed. Moreover, since the output control is only implemented in the transmitting side, wireless communication can be omitted. Finally, an experimental prototype with 330 W is built to verify the effectiveness of the proposed scheme. The results shows that the CP with ZPA can be achieved under significant misalignments, i.e., the coupling coefficient changing from 0.175 to 0.075, meanwhile, the measured efficiencies can be maintained at 88.13%-88.3%.

This paper proposes a high-efficiency underwater hybrid wireless power transfer (UHWPT) system with low plate voltage stresses to ensure a safe and stable power supply for underwater electrical equipment. The power transfer channel is constituted by an integrated magnetic-electric coupler, formed by nesting coils into C-shaped plates and integrating them into the LC -compensated topology. The system's working principle is analyzed in detail, providing the relationship among the circuit parameters, efficiency, and the same-side inter-plate (SIP) voltage. The impact of the geometric dimensions and insulation on electrical parameters is explored to provide a reference basis for designing the integrated magnetic-electric coupler. A system design method based on the double optimization parameters is hereby proposed. Then, an experimental prototype is set up to verify the feasibility of the design method. Experimental results show that the system achieves the load-independent constant current (CC) output with a maximum efficiency of 87.8%. Compared to the SS-compensated underwater inductive power transfer (UIPT) and capacitive power transfer (UCPT) systems at the same input power, the average suppression of the coil currents and the SIP voltage stresses of the proposed system is improved by 39.1% and 31.3%, respectively.

Electromagnetic field is used as medium for wireless power transfer to realize noncontact power transmission, which is hoped to be concentrated in the power transmission channel as much as possible to improve performance and reduce the impact on surrounding environment. A magnetic coupling mechanism (MCM) with omnidirectional magnetic shielding (ODMS) is designed in this article. Ferrite shielding layers are added at the back of power channel to guide more for power transmission and restraint leakage. The reverse-wound magnetic shielding coil and forward-wound power transmitting coil are connected in reverse series to form a bidirectional antiparallel coil, which eliminates the complex control and additional excitation source, and restrict magnetic in the side areas of power channel. Active and passive shielding methods are comprehensively used to improve the magnetic field distribution in the power transmission channel and reduce magnetic in the full space around MCM. The optimal design method of ODMS MCM is summarized, and the experiments are carried out. The results are consistent with the theoretical and simulation analysis. The proposed ODMS MCM can effectively limit magnetic leakage in all directions and improve transmission power and efficiency.

In this article, a novel load-independent capacitive power transfer (CPT) system with multiple constant voltage (CV) outputs is proposed. The capacitive repeater unit is designed to enhance the power transfer capability, which contains four plates where two plates are used to receive power from its previous unit and the other two plates transfer power to the next unit. Electric coupling between the receiving and transmitting plates in the repeater unit can be eliminated by placing them perpendicularly and employing the split-inductor matching network. The load is connected with each capacitive repeater unit so that multiple loads can be powered simultaneously. Aluminum oxide ceramic is placed between the two adjacent units to enhance their electric coupling. The $L$ -LCL network is adopted to compensate each capacitive repeater unit. Thus, CV outputs can be achieved for all loads, which ensure the independent operation of each load. The output voltages and efficiency are analyzed when considering the parasitic resistances. Finally, a three-load experimental setup is built to verify the effectiveness of the proposed system with an efficiency of 93.21%.