Voltage Balanced Control for a Hybrid Dual Bridge Series Resonant Converter

In this paper, the PWM plus phase-shift control with certain voltage balanced condition is applied to a hybrid dual bridge series resonant converter (HDBSRC). The control strategy is unified for the whole variation range of load, input/output voltage and with simple calculation. By using this voltage balanced strategy, the effective unity-gain operation condition can be obtained. A decoupled control can be derived then, in which the converter gain can be controlled by the PWM in the hybrid primary bridge and and load level is regulated by the phase-shift modulation. The equivalent unity-gain operation naturally extend the ZVS range and reduce the resonant current. A design example based on the analysis results is presented and then verified through experiment.