Analysis of LC-LC2 Compensated Inductive Power Transfer for High Efficiency and Load Independent Voltage Gain

This paper presents a novel LC-LC2 compensated resonant converter topology to achieve both high efficiency and good voltage gain controllability. An additional receiving side inductor working together with the receiving coil has the contribution to work with a large range of air gap distance. Due to this property, proposed compensation technique is effective for IPT based EV charging application. The frequency domain analysis of the proposed resonant converter provides the load independent voltage gain and ZPA of the input impedance. On the other hand, time domain analysis gives the circuit operation. A 500 W LC-LC2 compensated resonant converter prototype is built to testify the theoretical analysis. To perform the efficiency-comparison under different air gap, an S-SP compensated resonant converter with a similar amount of output power is also presented. In order to obtain the effectiveness, the proposed compensation method is verified by the experimental results. The maximum efficiency of the proposed compensated resonant converter is 93% at an output power of 500 W with a 140-mm air gap between the two sides of the IPT (inductive power transfer) transformer.