Indirect Control Strategy of Secondary Charging Voltage and Current and Transient Analysis of LCC-S WPT System

In this article, the steady-state and transient models of the LCC-S compensated wireless power transfer system (LCC-S WPT) are built. From the steady-state model, the secondary charging voltage and current are, respectively, proportional to the primary inverter current and coil current. Then the indirect control strategy of the secondary charging voltage and current based on the dual primary current closed-loop control is proposed. From the transient model, the controller parameters design criteria are given. The transient characteristics of the both side variables of the indirect control strategy are originally analyzed. It is proven that a good secondary transient performance is ensured under the indirect way. Furthermore, the feedforward control of the input voltage is proposed to eliminate its transient effect. The feasibility and practicability of the proposed control strategy are verified by the experiments.