Research On IGBT Open Circuit Fault Diagnosis And Fault Tolerant Control Of CRH3 Emus Electric Traction System

As the main power source of EMUs in railways,the reliability of electric traction system is directly related to the safe operation of trains.Since IGBT power tube is a key power device in the electric traction system,it is very important to research the fault diagnosis and fault tolerance control of IGBTs in EMUs,which can effectively improve the safety and reliability of the electric traction system.Taking the traction power converter IGBT power tubes of CRH3 electric traction system as the research object,this paper focuses on the open circuit fault diagnosis and fault-tolerant control technology.The specific research work is as follows:First of all,the simulation model of CRH3 electric traction system is established;by considering the DC side equivalent model of traction inverter during the operation of the train,the fault feature and effect of IGBT power tubes are analyzed,which provides a theoretical basis for fault diagnosis and fault tolerant control in the following paper.Secondly,for the open circuit fault diagnosis of IGBT in electric traction system,from the point of view of current signal,the time-domain expression of current residual at the primary side of tractive transformer is derived,and the relationship between the slope of current residual at the primary side and gate signal under different faults is established.Then analyzed the current characteristics of the d-axis before and after the fault,by combining with the average value of the three-phase stator side current under different failure modes,the diagnosis rules are formulated to locate the fault quickly.From the point of view of voltage signal,the normal and various open-circuit fault conditions of the power tube are analyzed,and the change of gate signal and AC side voltage is tried to be the formation basis of fault characteristic signal.This method can locate the single,double and multi tube faults of power tubes quickly and accurately,and are not affected by the load disturbance.Then,in the research of IGBTs fault-tolerant control,the PWM signal of normal IGBTs are processed for the fault IGBTs.and double-PWM rectifier fault-tolerant control strategy is given,which is easy to implement and has good effect.A full-speed flux linkage observer for asynchronous motor speed adaptation is designed.Considering the influence of neutral point voltage fluctuation,a fault-tolerant control strategy of three-phase four-switch traction inverter based on model prediction is proposed.Finally,Matlab / Simulink simulation model and small-step real-time simulation test platform based on Hardware in the Loop(HIL)and Rapid Control Prototyping(RCP)for fault diagnosis and fault tolerance control methods provide the basis for verification.The results showed that the fault diagnosis and fault-tolerant control method of IGBT proposed in this paper is robust,and is suitable for CRH3 EMUs electric traction system.