A conductance-controlled variable transformer turns ratio regulator for a zero-voltage-zero-current power switching converter

Abstract

This paper describes the application of the conductance control to a very high-efficiency parallel-regulated converter. Conductance control is one of the best ways of providing simplicity of design while preserving fast dynamic response and high reliability in power converters. The parallel regulator was conceived for space applications, to regulate a zero-voltage and zero-current power switching topology that works at constant frequency and constant duty cycle, but its range of applicability can be extended to any kind of power converter or inverter that utilizes a transformer to produce an isolated output. By using the concept of addition or subtraction of AC voltages, a fully regulated output voltage is achieved. The resultant effect of this regulation scheme is that the main transformer of the converter or inverter appears to have a variable turns ratio. This turns constant can be changed dynamically by means of a conductance control scheme and in almost a lossless way to maintain the converter (or inverter) outputs.