A Primary‐Side Control Method for Dual‐Parameter Identification and Constant Current Output in WPT Systems

ABSTRACT Wireless power transfer (WPT) systems are susceptible to dual disturbances caused by coil relative position offset and load resistance fluctuations. The mutual inductance and load resistance deviate from the set values, which in turn affects the stability and safety of the system. To address this problem, this paper proposes a method for the synchronous online identification of the mutual inductance of coils and the load resistance in the WPT system without wireless communication. By collecting the RMS value of fundamental current on primary side, the input impedance equation and current ratio equation of the mutual inductance and load resistance are established. In order to quickly identify the mutual inductance and load resistance of the system from the two high‐order equations, this paper proposes an improved Levenberg–Marquardt (LM) algorithm. The primary side controller of the system implements a phase shift control strategy based on the identification results to adjust the inverter output to ensure that the WPT system maintains a constant current (CC) output. Finally, a WPT system experimental platform is built and experimental verification is carried out. The experimental results show that the maximum identification errors of the mutual inductance and load resistance identified by the parameter identification method proposed in this paper are less than 3% and 4%, respectively, which can achieve CC output of the system under the disturbance of mutual inductance and load resistance.