Development and Testing of a Fault-Tolerant Modular Motor Drive using a PM Machine with Isolated Modules

Fault-tolerant modular motor drives (FT-MMDs) provide a promising approach for enhancing the reliability of motor drives in safety-critical applications. The machine is designed so that its stator can be excited by multiple independent inverters, enabling the drive modules to continue operating if one or more of the modules experiences faults. This paper presents the development of a 20 kW (rated) FT-MMD demonstrator unit using a high-performance PM machine excited by 4 independent voltage-source inverters and controllers. Testing has been carried out to measure the response of the FT-MMD demonstrator unit to a variety of fault conditions including both open- and short-circuit safe states applied to one of the modules. Preliminary tests with open-circuit and 3-phase short-circuit safe states have yielded promising results with phase currents remaining within safe limits at all times during the fault application period.