Research On MPCC-based Open-circuit Fault Diagnosis Method For Permanent Magnet Synchronous Motor Drive System Inverter IGBT

Permanent magnet synchronous motors have been gradually applied to intelligent manufacturing,transportation and other fields because of their high efficiency and fast response.The operation mode of motor drive system dictates that insulated gate bipolar transistors(IGBT)require frequent switching,which makes the IGBT also subject to great electrical stress at high temperatures,increasing the probability of open-circuit failure.Therefore,open-circuit fault detection and localization of IGBTs are of significant importance to improve the operational reliability of motor drive systems and reduce maintenance costs.Among motor drive control methods,Model Predictive Current Control(MPCC)has fast dynamic response and can flexibly handle multi-constraint and multivariable problems in nonlinear systems.In recent years,it has gained a lot of attention in the field of condition monitoring and fault diagnosis technology.This article takes the internal permanent magnet synchronous motor(IPMSM)as the research object,with the main goal of ensuring the health and stable operation of the motor drive system,and carries out research on the IGBT open circuit fault diagnosis method of the IPMSM drive system inverter.The specific research contents of the paper are as follows:(1)Rapidity is one of the key indicators in fault detection methods,while the diagnosis time of current detection method requires at least one phase current cycle.For the problem of long detection time of current detection method,the error current polarity method is proposed in this paper.This method combines the change of cost function in MPCC and current detection method,which can effectively reduce the fault detection time.(2)MPCC is susceptible to changes in motor parameters.Changes in load torque and speed can lead to changes or mismatches in motor parameters,which in turn can affect the output of the cost function leading to misdiagnosis.For the problem of misdiagnosis caused by load torque and speed variation,this paper normalizes the fault detection index and adds the counting method in the error current polarity method based on MPCC.It further improves the robustness of the method based on the guaranteed accuracy.Finally,the simulation and experimental verification were carried out by Matlab2016b/Simulink simulation software and 2kW IPMSM drive system IGBT open-circuit fault diagnosis experimental platform with TMS320F28335 as the control core,respectively.Both simulation and experimental results show that the method can detect and locate 18 open-circuit fault types by using only the changes of three-phase current and cost function signals as fault detection indicators,and will not cause misdiagnosis when the torque and speed change.