A dual-coupled inductor-capacitor-capacitor and series (LCC-S) compensated wireless power transfer (WPT) system with a compact receiver size is proposed in this paper to improve the misalignment performance and achieve fault tolerant operation as well as a stable output power. The compensation coil and the main coil are integrated as two decoupled unipolar coils on the transmitter side, while they are both coupled with the receiver coil. The two mutual inductances among the two decoupled coils and the receiver coil have opposite impacts on the output power when they both increase or decrease. Therefore, the output power can remain stable when the misalignment increases. The short- and open-circuit characteristics are analyzed, which demonstrates that the proposed topology can achieve both short- and open-circuit protection. A prototype was built and the experimental results verified the theoretical analysis and simulations. The system can deliver from 297 W to 321 W when the x-misalignment increases from 0 mm to 90 mm, with a dc-dc efficiency of 92.78% to 93.56%. The proposed WPT system can be used for the wireless charging of e-mobility scooters and autonomous underwater vehicles. The system can provide a stable output and can tolerate both short- and open-circuit faults at the output.

In high-power electric vehicle wireless charging systems, the charging distance is short, and the coupling is strong in order to increase the power density and reduce the coil size and the system cost. With a strong coupling, the receiver-side compensation can be eliminated, and a high efficiency can still be obtained. The inductor-capacitor-inductor-none (LCL-N) topology is formed with the LCL compensation on the primary side. The phase difference between the transmitter and receiver currents is larger than 90°, leading to the magnetic flux cancelation in the ferrites. Thus, the required ferrite thickness of the LCL-N topology is smaller than the fully-compensated topologies. Therefore, a compact, lightweight, and low-cost receiver structure is achieved with the omitted compensation and thinner ferrite. Moreover, the LCL-N topology can achieve zero voltage switching for all loading conditions, withstand open-circuit and short-circuit faults, and is suitable for constant-current and constant-voltage charging due to the fact that it has neither a CC nor a CV output characteristic. A 100-kW system is designed and simulated. A downscaled 1-kW system is implemented. The simulations and experimental results verify the effectiveness of the analysis.

Capacitive power transfer (CPT) has garnered significant interest in recent years, driven by efforts to enhance power and efficiency. This article presents advancements in CPT technology, focusing on the design of a novel five-plate coupler and the optimization of CPT systems. The proposed five-plate coupler features single-side shielding, which aims to simplify design complexity and reduce costs while maintaining performance. This study characterizes the five-plate coupler and compares its performance to traditional even-numbered plate configurations, highlighting the differences between odd and even plate designs and the unique characteristics of asymmetric couplers. In addition, the factors influencing efficiency are investigated, and an optimization method for CPT systems with asymmetric couplers is proposed to enhance the overall system performance. Experimental validation includes the development of a 5-kW prototype CPT system with a 100 mm airgap, achieving an impressive efficiency of 96.5%. These findings underscore the potential of the proposed design and optimization approach to set new benchmarks for CPT systems, facilitating their broader application in high-power scenarios.

This paper proposes a novel battery cell balancing topology with reduced component count and simplified control. The balancing algorithm is based on the state of charge (SOC) of each individual cell instead of cell voltage. The principle of the proposed topology is analyzed and verified through simulation and experiments. Then an experimental battery test workbench is established to validate the proposed balancing algorithm. The experimental results show that the proposed balancing topology and associated algorithm can perform well in real applications.

Wireless power transfer (WPT) is more convenient and safer than conductive charging for power consumer electronics, biomedical devices, transportation systems, etc. Inductive power transfer is the most widely studied and commercialized WPT technique; however, capacitive power transfer (CPT) is becoming an attractive alternative, offering better misalignment tolerance and lower cost and weight. The electrical-field-resonance-based six-plate coupler system is one of the most typical configurations for high-performance CPT systems, but the associated large number of circuit parameters is always a critical issue for system design. In this article, a parameter optimization method is proposed for this topology. The ratio of the reactive power in the compensation network to the system transferred power is set as the main optimization goal. To solve the high-order optimization problem, a two-stage method is proposed to significantly reduce the optimization complexity while providing the optimized parameters of the whole system. To verify the effectiveness of this method, a 3-kW, 1-MHz CPT system with a 16-pF coupling capacitor is built. Both the simulation and experimental results show that the optimized parameters effectively improve the system efficiency, experimentally achieving 95.7% dc–dc overall efficiency under a 100-mm gap distance at the rated power.