Variable Compensation Network for Achieving Constant Current or Voltage Output in IPT System

This paper is intended to investigate a variable series-series (SS) compensation network of the loosely coupled transformer (LCT) in the inductive power transfer (IPT) system. With the proposed compensation network, an additional switch is used to facilitate the transition from the LC resonance condition to three order T-type resonance condition with the same operating frequency to achieve constant current (CC) constant voltage (CV) charge for EV (electric vehicle) system. The resonance conditions, output current or voltage, and efficiencies of compensation network are deduced both in CC mode and CV mode. An IPT EV charging system is designed. Zero current switching (ZCS) operation condition in CC mode and zero voltage switching (ZVS) in CV mode are achieved for all primary side MOSFETs, and 88.6 % efficiency in CC mode and 79.2 % efficiency in CV mode for the proposed compensation network achieved.