A Novel Source-Side Monitored Capacitive Power Transfer System for Contactless Mobile Charger Using Class-E Converter

A new source-side monitored capacitive power transfer system (CPTS) for contactless mobile charger using Class-E converter is proposed. Contrary to conventional contactless mobile charger, an exact battery voltage monitoring is achieved without additional cumbersome communication circuits. The proposed CPTS operates in two iterative modes; a main-charging-mode and a sub-battery-monitoring-mode. Not only the battery voltage sensing but also an agile battery charging current control is accomplished with a microprocessor at a transmitting side. The circuit parameters of class-E converter and primary circuit, which consists of the compensating inductors and the capacitive coupled metal plates, are determined for guaranteeing load tolerance. A detail analysis for the battery monitoring operation and design procedures of the proposed CPTS are fully established, and experimentally verified for 4 W prototype of Samsung GALAXY S3 Li-ion battery at the switching frequency of 1.237 MHz.