A Ringing Effect Mitigation Strategy using Double Pulse Test for SiC based DAB Converter

Abstract

The increasing adoption of wide bandgap devices in high density and high frequency converters has led to an improvement in overall efficiency. However, the faster switching of the devices exhibits ringing because of the interaction of the parasitic inductance (Lstray) and output capacitance (Coss). This ringing can damage the device, causes electromagnetic interference (EMI) and reduces the overall reliability of the converter. This paper presents a methodology to determine the optimal turn-off snubber to mitigate the above problems. A Double Pulse Test (DPT) is used to model the switching characteristics of SiC MOSFET and subsequently a parametric analysis is performed to determine the optimal snubber resistor (Rs) and capacitor (Cs). The designed snubber is then validated both by simulation and experiment using the SPS controlled DAB converter. The results demonstrate that the designed snubber reduces the peak voltage, oscillations, and DPT provides an effective practical platform for the design of snubber for power electronics converters. This work can be extended further by including a ZVS based closed-loop control for the DAB converter and its experimental validation.