Comparison of Control Techniques for Series Resonant Converter

Abstract

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

Implementation of the irregular pulse density modulation‐controlled wireless power transfer system for constant current and constant voltage output

“…In the PSM technique, the inverter operates at a fixed frequency and power control is adjusted by changing the phase angle of the gate signals. The disadvantages of PSM are as follows: The phase angle increases, the hard switching occurs, and it causes electromagnetic interference (EMI) [13]. Variable frequency PSM has also been proposed to get rid of hard switching in PSM [14].…”

“…In this technique, power is controlled at the resonant frequency under soft switching conditions [16]. However, subharmonics may occur during damped oscillation state [13]. These subharmonics can be minimized by arranging the pulse sequences at an optimum level in irregular PDM [17].…”

“…PDM control can be divided into burst mode PDM [20], delta-sigma PDM [21], regular PDM [13], and irregular PDM [18]. In burst mode PDM, discontinuous mode operation is prevented, but subharmonics are produced.…”