Research on Input-Parallel Single-Switch Wireless Power Transfer System With Constant-Current and Constant-Voltage Output

The full-bridge can further improve the output power through parallel inverters. The inverter output voltage of single-switch LC-resonant circuit is a combination of trapezoidal wave and half-sine wave; there is no relevant research on parallel connection of single-switch LC-resonant circuit. Therefore, this article presents a novel input-parallel single-switch LC-resonant circuit; this topology adopts switchable secondary networks for constant-current (CC) and constant-voltage (CV) output, and prevents shoot-through of power switches. The decoupling between transmitters simplifies the analysis and calculation. The input-parallel structure avoids the unbalanced input voltage of each inverter and improves the stability of the wireless power transfer system. CC and CV output modes can be achieved by controlling one relay without adding dc-dc converters or changing the switching frequency. This article includes decoupling equivalent analysis of coils, topologies analysis of CC mode and CV mode, calculation of equivalent input ac voltage source, design of magnetic coupler, and circuit parameters. Finally, a 1-kW experimental prototype is built to verify the theoretical analysis; the maximum efficiency can reach up to 92.5%.