Analysis of rectifier topologies for automotive HV to LV phase shift ZVT DC/DC converter

Full bridge phase shift zero voltage transition (ZVT) converter is a standard topology for the automotive high voltage (HV) to low voltage (LV) DC/DC converter. One of the major issues due to the required wide input and output voltage range is the voltage overshoot during the turn-off process of rectifier MOSFET switches. This paper presents a model to simulate turn-off voltage waveforms of switches for different rectifier topologies. Experimental verification on a 3kW converter prototype shows that the model is accurate regarding voltage overshoot value and the oscillation frequency, and that reverse recovery of body diodes has no significant effect on the overshoot. In comparison to two other rectifier topologies, the bridge rectifier has the lowest requirements regarding the switch breakdown voltage, resulting in decreased power losses and eliminating the need for complex clamping/snubber circuits in this specific application.