A Voltage Controlled Oscillator (VCO) Based Controller and Feedback for a Single Switch SiC Class-E Resonant Inverter

Increased electrification of applications such as home automation, vehicle technology and health equipment continue to increase; power electronic solutions are becoming increasingly common. High performance and size are challenges of typical inverter circuits, which require advance control and several expensive sensors. Resonant converters have the potential to increase efficiency, if optimal design and accurate control are employed, which may be simplified if the number of switching elements is reduced. A Class-E inverter is a resonant topology that only requires a single switch. As the topology requires a high Q factor of 7, small variations of frequency around the resonant frequency can control the output voltage magnitude. Output voltage magnitude regulation is accomplished through voltage feedback, to generate the proper frequency gating signal, to reach desired output voltage magnitude. An analog based VCO control is proposed in this paper, which may be employed in other resonant topologies as well. A prototype was built and verified for proper operation.

I. Introduction

The increased electrification of applications such as transportation, appliances, and increased penetration of renewable energy systems and utilities interfaces has made reliable, low cost, high-frequency power supplies increasingly essential [1]–[3]. Resonant converters have been increasingly used to meet these requirements. This is due to the lower switching losses as a result of zero-voltage-switching (ZVS) and zero-current-switching (ZCS) operation. This has resulted in very high efficiency and light weight systems [4], [5].