Common-Source Inductance Induced Voltage Overshoot and Oscillation in Active Bidirectional Devices

Common-source inductance (CSI) is proven to be detrimental for high-speed switching. It can significantly slow down switching speed and increase switching losses. Recent research also demonstrated a self-turn-on phenomenon during the device turn-off transient in a simple buck converter. Yet there is lack of literature investigating the impact of CSI in circuits using bidirectional devices. This letter aims to first demonstrate and then reveal the mechanism of a unique turn-off voltage overshoot and oscillation phenomenon in converters using active bidirectional devices. The issue is found to be associated with the CSI in the bidirectional devices and can result in more than 100% voltage overshoot and significantly higher switching loss during the turn-off transient. Practical solutions are also provided to attenuate or eliminate the detrimental effects. The phenomenon and provided analysis are demonstrated and verified on a custom-built SiC-based matrix converter phase-leg.