ABSTRACT In a strongly coupled wireless power transfer (WPT) system, the secondary‐side uncompensated structure can be applied, forming a series‐none (S‐N) topology to reduce the volume and cost of the receiver. The compensation of the S‐N topology depends on the coupling coefficient, which can be varied with offset. This paper proposes a parameter identification method for the S‐N topology to retain a constant‐voltage (CV) output with offset. A method for identifying the coupling coefficient and the load resistance is proposed by detecting the primary‐side voltage and current and then adjusts the resonant frequency to achieve a CV output. The system can realize a stable CV output under arbitrary load conditions and offsets. A WPT experimental prototype is built to verify the accuracy of the parameter identification. Under offset conditions, the maximum error of the coupling coefficient identification is 1.51%, and the load resistance identification accuracy is maintained between 93.93% and 99.1%, indicating high identification accuracy. A CV output can be achieved with a voltage fluctuation of 4.67%.
Zhang et al. (Sat,) studied this question.