Experimental Evaluation of Dead Time Reverse Conduction Losses in Motor Drives Applications

Abstract:
The paper deals with the dead-time impact on the reverse conduction of low-voltage GaN FETs in inverter topology for motor control applications. The current variation in AC motor drive leads to a different dead-time losses mechanism compared to the DC-DC converter. In the paper, the dead-time in the inverter leg is correlated with both current variation and GaN reverse conduction, through an experimental evaluation. Furthermore, a comparison of the GaN FET with a MOSFET with similar parameters in reverse conduction operations is carried out to show the similarities and differences in switching behavior and power losses. Finally, the paper aims to give designers a guideline on the limits and optimum dead-time selection in a GaN FET based inverter leg for motor control applications.