The Open Fault Diagnosis And Fault-tolerant Control Of PMSM Drive System

The open-circuit fault diagnosis and fault-tolerant control research of thepermanent magnet synchronous motor drive system in recent years have becomeone of the hot race at home and abroad, but because of the instability of theswitching power devices after a long time running and power electronic devices dueto their vulnerability, inverter failures takes place frequently, plus some causescreate the stator winding open circuit fault, limits the use of the permanentsynchronous motor drive in the field of high-reliability applications. In order tomake the PMSM drive system is able to continually run in the open-circuit fault,therefore, carrying out the study of the open-circuit fault diagnosis andfault-tolerant control for PMSM drive system has important theoretic research andengineering application value.This paper based on the mathematical model of interior permanent magnetsynchronous motor and the vector control theory, proposed a scheme of detectionthe current vector trajectory slope to locate and achieve the open circuit faultdiagnosis under normal and fault condition, because of the stator current harmonicand measurement noise, the slope of the current vector trajectory is easy to shock,to solve the problem, fundamental extraction is firstly designed to improve theaccuracy of the fault diagnosis.A three-phase four-bridge inverter fault-remedial control strategy is proposedbased on the inverter single phase bridge fault or the stator winding fault. When thefault is determined, immediately isolate the faulted phase, the system automaticallyswitches the new fourth inverter pole to connect the neutral point of the motor. Toimprove the performance of fault tolerant systems, we design the voltagefeed-forward compensation and combined with the current PI regulator, the currentwill output the stability of reference voltage vector and then the motor will havestable torque. Finally, integrated open-circuit fault diagnosis、fault-tolerant controland the IPMSM vector control system as a whole, through the simulation system,we study the system performance under the open-circuit state and fault-tolerantstate, and realize the safely and reliably operate of IPMSM drive system.