Mutual Inductance Identification of Wireless Power Transfer Based on Second Harmonic

This paper proposes a novel method for identifying mutual inductance in wireless power transfer systems. When the input voltage of the uncontrolled rectifier on the receiver side is a square wave with a 50% duty cycle, the voltage comprises only the fundamental frequency and odd harmonics. if a second harmonic is introduced into the voltage on the transmitter, the equivalent circuit for the second harmonic can be considered a short circuit on the receiver. By measuring the amplitude of the second harmonic in the current and voltage output from the inverter, the input impedance of the second harmonic can be obtained. Integrating the input impedance with the coil's self-inductance and resonant capacitor parameters allows for the direct calculation of the system's mutual inductance using the impedance formula. This method is simpler and requires less computational effort compared to traditional mutual inductance identification methods.