Phase-shifted series resonant DC-DC converter for wide load variations using variable frequency control

Abstract

This paper presents a phase-shifted DC-DC resonant converter type LLC. The proposed converter provides high output voltage gain with wide zero voltage switching (ZVS) range. The converter achieves wide load variation by utilizing variable frequency control, where the gain of the converter is analyzed in relation with the tank impedance that depends on the switching frequency to resonant frequency ratio. Moreover, the utilizing of the magnetizing inductance and the phase shifted angle ensures the achievement of the ZVS for all switches. The proposed converter was simulated using MATLAB-Simulink software. It was found that the variable frequency control is suitable for LLC resonant converters in terms of obtaining wide load variation. The simulation results have proved that the proposed converter can offer wide load variation up to 25% of the full load, with efficiency of 80%.