Switch Short-Circuit Fault-Tolerant Control of Five-Phase Open-Winding Motor Drive with a Floating Capacitor

This paper proposes a switch short-circuit (SC) fault-tolerant control (FTC) method for the open-winding topology with a floating capacitor, where the main inverter is supplied by a DC source, and the floating inverter is merely supplied by a capacitor. The SC faults are divided into two types and analyzed in detail. For the fault of Type I, the proposed reconfiguration strategy can isolate the faulty device to ensure stable operation. For the fault of Type II, the control of zero-axis voltage in the topology is introduced to replace the control of the faulty bridge. Besides, the fault-tolerant power smoothing strategy is applied to suppress the low-frequency ripples of the floating capacitor voltage and input current from the DC source, which further improves the torque quality. Compared with the previous method, the proposed FTC method does not require additional hardware costs to convert the short-circuit to an open-circuit. Meanwhile, the motor can still give out rated torque even after the fault. The performance of the proposed FTC method is verified experimentally in an open-winding five-phase induction machine system.