Fault tolerant system under open phase fault for BLDC motor drives

In this paper, the fault tolerant system for BLDC motor has been proposed to maintain the control performance under the open fault of inverter. The fault identification method is proposed to two different types. The one is the method by the difference between reference and actual current. The other is the method using additional voltage sensors across lower legs of inverter. The reconfiguration scheme is achieved by the four-switch topology connecting a faulty leg to the middle point of DC-link using bidirectional switches. The proposed fault tolerant system quickly recovers the control performance by short detecting time and reconfiguration of system topology. Therefore, continuous free operation of the BLDC motor drive system after faults is available. The feasibility of the proposed fault tolerant system is proved by simulation.