Self-Oscillating Resonant Converter With Contactless Power Transfer and Integrated Current Sensing Transformer

In this paper, an integrated transformer is proposed to provide current sensing in the primary side and passive current phase detection for a self-oscillating contactless resonant converter (SOCRC). The proposed transformer integrates power transfer and current sensing. By using the secondary current phase of a series/series-compensated resonant converter in the control of the inverter, better output controllability, dynamic response, and self-adaptability can be achieved simultaneously. The integrated current sensing winding, being a crucial part of SOCRC, is analyzed in detail. In order to make the output voltage insensitive to the clearance and misalignment conditions, the requirement of the new integrated transformer is given. Experimental results of an 80-W SOCRC prototype verify the analytical results.

I. Introduction

An inductive power transfer (IPT) system transfers power from one circuit to another through electromagnetic induction without any physical contact. It has been used in various applications ranging from a few milliwatts in biomedical applications up to several kilowatts of output power in automotive applications [1]–[4]. Due to its convenience and safety against electric shock, IPT has become increasingly popular in home appliances, mobile devices, industrial sensors, and electric vehicle (EV) chargers [5]– [7].