A PS/S Current-fed IPT System with Variable Capacitors (VCs) for Achieving ZPA Operation

Zero-phase-angle (ZPA) operation is considered as a method to minimize the volt-ampere (VA) ratings and maximize transfer power to the load in the inductive power transfer (IPT) system. However, the ZPA operating prerequisite is quite sensitive to the variation of parameters such as IPT system coupling coefficient and load conditions. A parallel-series/series (PS/S) current-fed IPT system with a new variable capacitors (VCs) structure is proposed to achieve ZPA operation and constant output voltage at fixed frequency. The detailed analysis and mathematical model of the variable capacitors network are reported. The proposed VCs structures in PS/S current-fed IPT system are discussed, analyzed and compared with existing competitive topologies in the literature. The experimental results obtained from 65-W lab-prototypes are demonstrated to verify the analysis and performance.