Exploring Interactions Between Reflected Wave and Partial Discharge in WBG Motor Drives

Partial Discharge (PD) and reflected wave phenomenon have emerged as major concerns for motor drive design due to increase switching speeds of Wide Band Gap (WBG) devices. This paper deals with modeling and quantification of this high frequency phenomenon This paper proposes a frequency sweep-based cable and motor model considering skin and proximity effects for three-phase power cable. Proposed modeling approach can predict Reflected Wave overvoltages with 93% accuracy. Further, the concept is extended to the analysis and detection of PD in motor windings due to such over voltages. PD tests are performed using robust RF PD detection method at various square wave voltage levels. It is observed that the number of PD events and strength increases exorbitantly with small increase in voltage above the Partial Discharge Inception Voltage (PDIV).