Multi-Parameter Estimation for an S/S Compensated IPT Converter Based on the Phase Difference between Tx and Rx Currents

Abstract

This paper proposes a multi-parameter estimation method based on the phase difference between primary and secondary currents, for a series/series (S/S) compensated contactless converter. To achieve secondary current sensing in the transmitter side, a primary sensing coil is added into the coupler. By introducing the phase difference between primary and secondary currents, a straightforward, multi-parameter estimation model is derived, significantly reducing the multi-parameter solving difficulty. Based on the derived model, a method combining pre-parameter identification based on frequency sweeping, with fast online parameter identification is proposed, offering a general, accurate, and rapid parameter estimation solution. Detailed implementation of the parameter identification method and the asymmetrical configuration of the coupler are also presented. The proposed method is verified with a 1 kW S/S compensated converter. Experimental results show that the estimated values agree well with the theoretical ones. Based on the estimated results, the transmitter-side, closed-loop control can also be achieved.

Keywords

• parameter estimation
• transmitter-side control strategy
• wireless power transfer
• constant current and constant voltage output