A Multilevel Inverter Topology for Inductively Coupled Power Transfer

This paper describes a multilevel inverter that can synthesize quantized approximations of arbitrary ac waveforms. This converter could be used to deliver power over multiple frequencies simultaneously. Unlike traditional multilevel inverters, this topology does not require an external voltage balancing circuit, a complicated control scheme, or isolated dc sources to maintain its voltage levels while delivering sustained real power. In this paper, we use this circuit for heating frequency selectable induction targets designed to stimulate temperature sensitive polymer gel actuators. For this application our multilevel inverter offers higher efficiency than a pulse width modulated full-bridge inverter (a more conventional power supply solution) at comparable levels of total harmonic distortion