Modeling and Control Strategy for Zero Voltage Switching Condition in Series-Series Compensated Inductive Power Transfer System

The zero voltage switching (ZVS) condition should be maintained in the inductive power transfer (IPT) system supplied by inverter. It can be obtained when current lags the voltage of the inverter. In this paper, a modeling and control strategy is presented to maintain the ZVS condition of the IPT system. The equivalent impedance angle of the system can be regulated through adjusting the operation frequency. An equivalent circuit model of the IPT system supplied by a half-bridge inverter is firstly developed for analysis. Then the model is linearized around the operation point using small-signal method and is reduced with balance realization method. Based on this low-order model, the transfer function of this model is obtained and a PI controller is presented in discrete-time domain to stabilize the impedance angle. Finally, the simulation results verify the correctness of modeling and the effectiveness of the proposed controller.