A Novel Two Degrees of Freedom Control Strategy for PS/S Current-fed IPT System

In order to achieve good transmission characteristics of ICPT system, zero-phase-angle (ZPA) operation and constant voltage output characteristics are always required. However, the operating point is significantly affected by the variation of the magnetic coupling and load conditions. This paper presents a two-degree-of-freedom control strategy for a parallel-series/series IPT network. ZPA operation is achieved by controlling the phase shift angle of the switched capacitor. On this basis, a new three-level current control strategy is proposed to achieve constant voltage output. The detailed steady-state operation, control strategy, small-signal modeling are reported, and the theoretical results are validated with a 120W lab-prototype.