Comparison of Control Techniques for Series Resonant Converter

Abstract

There are many different derivatives of variable and fixed frequency switching controltechniques used in control of load resonant converters. In this study; among these techniquesfrequency modulation (FM), phase shift modulation (PSM) and pulse density modulation(PDM) are applied separately to series resonant converter (SRC). The techniques are examinedand compared in many respects. An experimental setup is built, which consists of a 400Wconverter, a control circuit and a resistive load to verify theoretical studies. The converter iscontrolled by FM, PSM and PDM separately for 120 kHz basic operating frequency anddifferent output currents. Experimental results are compared in terms of efficiency, outputvoltage ripple, soft switching, switch voltage, ease of application and hardware. The comparisonresults are presented. Thus, effect of each technique on the operating parameters of theconverter is revealed. Moreover, it is also observed that FM has better performance than theother two techniques in many aspects