Optimal Active Short-Circuit Operation of Permanent Magnet Synchronous Machines and Drives for Aerospace Applications

Active short-circuit is used as a protective measure in motor-drive systems to deal with various faults in electrical machines and converters. It is particularly attractive for aerospace applications that demand high power density and reliability. However, due to potential large short-circuit current under stationary and transient states, active short-circuit operation poses critical challenges to the design of both electrical machines and power converters. This paper proposes optimal active short-circuit strategies to minimize steady-state stress on individual power switches and suppress dc offsets in transient currents. As a result, the short-circuit current withstand level of the motor-drive system is significantly increased. Compared to conventional approaches, the withstand levels for the classic two-level converter and active neutral point clamping (ANPC) converter are improved by 40% and 90%. This generic approach is applicable to various inverter topologies and multiphase machines/drives.