An Impedance Matching Network Tuning Method for Constant Current Output under Mutual Inductance and Load Variation of IPT System

This article proposes a double-sided inductor-capacitor-capacitor-capacitor matrix (D-LC-CCM) impedance matching network to eliminate the impact of the load and the mutual inductance variation on inductive power transfer system. A thorough mathematical analysis is conducted and a control strategy is proposed to obtain a constant current output when the load and the mutual inductance vary. When the load changes, the equivalent impedance of the secondary side can be kept unchanged by adjusting the capacitor matrix in the receiver, then adjusting the input voltage can achieve constant current output simultaneously. The equivalent input impedance of the primary side and the output current can remain stable by adjusting the capacitor matrix in the transmitter when the mutual inductance changes. The experimental prototype was built, and the system constant current output was achieved when the load changes from 40 to 80 Ω and the mutual inductance varies from 13 to 17 μH, which has validated the effectiveness of the D-LC-CCM impedance matching network.