A Multi-Output Modular Wireless Power Transfer System with Constant-Current Characteristic

In the medium- and high-capacity power applications, typically multiple switches connected in series and parallel are used in power electronic converters to handle high voltages and currents. Powering the driving circuits and auxiliary units with high insulation requirements is challenging. This article proposes a modular multi-output wireless power transfer (WPT) system with constant-current (CC) output characteristics for auxiliary power supply. Compared with conventional solutions, there is no need for complex control circuits and much magnetic material. The dual-frequency topology with CC outputs is derived by applying the analytical method that used to obtain the dual-frequency topology with constant-voltage (CV) outputs. The conditions for the system to maintain zero phase angle (ZPA) at different frequencies are discussed. Lower output fluctuations than single-frequency multi-output systems and dual-frequency CV output systems are verified. A magnetic coupler with integrated compensation inductors is designed to eliminate the need for discrete inductors and improve the power density. An experimental prototype is built to verify the validity of the theory. The WPT system achieves an output current fluctuation of no more than 4.78%, a maximum system efficiency higher than 85%, and an output power of more than 10 W at a single port, which can well meet the requirements of auxiliary power supply.