Utilizing Voltage Transients to Identify Mutual Inductance and Load Voltage of Wireless Power Transfer System

Identifying the mutual inductance and load voltage is important for controlling and optimizing the wireless power transfer system. This article proposes a novel identification method based on the voltage transients. Connecting an equivalent sensor inductor in the primary resonant tank, the voltage transient values caused by the rising and falling edges of the inverter output voltage and the rectifier input voltage are relevant to the mutual inductance and load voltage. By detecting the voltage transient amplitudes, the mutual inductance and load voltage can be identified directly for the strong coupling case. For the weak coupling case, the current amplitude in the primary resonant tank is further utilized to handle the sensitivity problem. Sensitivity analysis shows that the proposed method can also perform satisfactorily even when the system parameters have some errors. Finally, experiment results verify the effectiveness of the method.