A Family of Balance Circuits for Inductive Power Transfer Systems to Reduce Common Mode Noise

In high-power inductive power transfer (IPT) systems, switching-induced common-mode (CM) noise is an important challenge that hinders industrial applications. In this paper, an analytical model of the distributed ground capacitance of coils is presented, followed by the determination of the ground asymmetric impedance of the upper and lower bridge arms. Subsequently, the application of a balance circuit is utilized to compensate multiple IPT systems, effectively achieving the suppression of CM noise. Furthermore, a novel CM impedance is introduced for analyzing the CM noise model of IPT systems, allowing for the evaluation of the suppression effects of balance circuits in SS, LCC, and LCL topologies. Finally, an 11kW LCC compensation IPT system is constructed, and frequency scanning tests are conducted. The implementation of the compensation structure with the balanced circuit demonstrates efficient CM suppression within the frequency range of 1MHz to 30MHz.