Primary Capacitance Control of S-S Compensated IWPT Link Voltage Gain

In the application of wireless power transfer systems constant voltage output is often desirable in situations where variance in distance and misalignment between the transmitter and the receiver is unavoidable. This geometric variation calls for the design of robust systems which can operate under different values of coupling coefficient which changes as a function of positioning. This paper illustrates the problems caused by coupling coefficient deviation through output characteristic analysis and demonstrates a solution where varying the primary side capacitance through the use of a switched capacitor can be used to attain constant voltage output for varying conditions. The proposed method is analytically proven and verified in simulation and a practical Series-Series compensated topology is presented in this paper.