Improved Pulse Density Modulation for Semi-bridgeless Active Rectifier in Inductive Power Transfer System

Abstract

This paper proposes an improved pulse density modulation (IPDM) power control method for semi-bridgeless active rectifier (SBAR) in inductive power transfer (IPT) system. In this method, the input voltage pulse sequences of the SBAR can be distributed more evenly compared with the traditional PDM, so the output voltage ripple can be reduced effectively. Besides, for multiple paralleled pickups, the interleaved IPDM is developed to further suppress the output voltage ripple. In addition, the characteristics of zero-voltage switching and zero current-switching for the SBAR's switches can also be achieved in the proposed IPDM method by synchronization control for the gate signals of the SBARs. The experimental results on a 30 kW IPT prototype with four paralleled pickups verified the proposed method.