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In order to improve the integration and life time of ac voltage input wireless power transfer (WPT) system, a topology based on electrolytic-capacitor-less matrix converter with inductor-capacitor-capacitor-series (LCC-S) resonant network is proposed. The relationship between the conversion ratio of the output and input voltages and resonant parameters are analyzed. It reveals although the boost operation is achieved by the parameter design of LCC-S network, it makes the system sensitive to the parameter variations. In order to extend the voltage conversion range, the improved two-stage WPT system based on the single-stage one is proposed. The dual-side closed-loop control of the two-stage system without the wireless communication is further proposed. The corresponding small-signal model is built and the parameters of the closed-loop controllers are designed. The feasibility and practicability of the proposed system are verified by the experiments.

In this letter, an integrated wired/wireless charging topology is proposed to expand the adaptability of the electric vehicle charging stations and further improve the utilization of the charging facilities and venues. By reusing the common structures in the independent wired and wireless charging topologies, on the basis of achieving the wired and wireless charging functions, the integration of charging facilities is improved, and its cost is reduced. Based on the isolated converter in the wired mode, a frequency tuning strategy in the wireless mode is proposed to overcome the frequency detuning problem caused by the parameter fluctuations. The feasibility and practicability of the proposed topology and the frequency tuning strategy are verified by the experiments.

In the LCC-LCC wireless power transfer (WPT) system with the secondary buck converter, the overvoltage (OV), and overcurrent (OC) faults occur when the secondary buck converter is shut down suddenly. To ensure safety, this issue is analyzed at the transient level and the dual-side indirect closed-loop control strategy is proposed to achieve the closed-loop control of the terminal voltage and the secondary dc bus voltage. The secondary dc bus voltage is under the indirect control by the closed-loop control of the primary inverter current and this conclusion is proven in the transient level. Under the dual-side closed-loop control strategy, the two-stage WPT system forms a cascade system and there is the instability problem. The integrated design criteria of the dual-side controller parameters based on the cascade system stability theory are given. The feasibility and practicability of the proposed control strategy and parameter design method are verified by the experiments.

To significantly reduce switching loss of the high frequency inverter in battery wireless charger (BWC), improve the soft-switching stability and system reliability, a novel soft-switching BWC with low loss auxiliary network and reconfigurable rectifier is presented. The presented soft-switching BWC can implement the smooth switching between constant current mode and constant voltage mode without frequency switching and relays, which is beneficial to enhancing the system stability. With the help of a novel low energy consumption auxiliary circuit, the power switch tubes in the H-bridge inverter can implement zero-voltage soft switch-on and zero-current soft switch-off in the full range, completely eliminating switching loss of the inverter. The proposed scheme can enhance the system efficiency while refraining from the soft-switching range limitation and soft-switching failure caused by the system parameter perturbation. Finally, a 1-kW soft-switching BWC principle prototype is developed to validate the effectiveness and correctness of the proposed scheme.

Five-phase open-end winding permanent magnet synchronous motor (OEW-PMSM) fed by a dual inverter has gained increasing focus because of its advantages in voltage utilization, torque density, and reliability. In this article, an optimized modulation method with the sliding clamped strategy is proposed for the five-phase OEW-PMSM drive with a common dc bus. The conventional clamped strategies have a reduced switching sequence. However, the clamped inverter generates the zero-sequence voltage and third harmonic voltage, which would affect the performance of the motor. To solve this problem, the reference voltages in the proposed method are distributed by limiting the reference voltage of the clamped inverter on a line. And the reference voltage slides on this line bidirectionally. Therefore, the clamped inverter in the proposed method will not introduce additional harmonic components. For experimental verifications, the test results are presented with the resistance-inductance load and five-phase OEW-PMSM.