Consideration of Operating Condition of Secondary-side Converter of Inductive Power Transfer System for Obtaining High Resonant Circuit Efficiency

Abstract

Contactless power transfer (CPT) system is of interest because of its potential for use in electric vehicle chargers. The system can make convenient to charge the battery on electric vehicles even on a rainy day. However, there are some barriers that should be overcome for the practical realization of the CPT system. These include parameter variation associated with the parking position at a parking lot and the low system efficiency. Several CPT schemes have been proposed and researched. This paper reviews inductive CPT system in these schemes. First, a theoretical formula suitable for treating two kinds of parameter variations associated with the caused by coupling state between the primary and secondary coils or parking position is derived. Next, a maximum efficiency operation scheme is proposed on the basis of the formula and theoretical analysis. Experimental results show the effectiveness of the proposed operation scheme.