The Research Of Power Switch Fault Diagnosis And Fault Tolerant Strategy In Two-stage Matrix Converter

Matrix converter(MC)has great application prospect in the field of electric system and power transmission because of its excellent input /output performance,controllable input power factor,reversible energy transfer,compact structure.In these fields,the operation reliability of power converters are high requirements.So the real-time online diagnosis and appropriate fault-tolerant control to improve MC system reliability is of great significance.At present,the fault diagnosis method and the fault-tolerant control strategy of MC mentioned in the references are mainly proposed for conventional matrix converter(CMC).In this paper,the fault diagnosis method and fault-tolerant control strategy of two-stage matrix converter(TSMC)power switch are studied.Firstly,this paper introduces the research background and significance of fault diagnosis and fault tolerant control strategy for MC power switch,then introduces and summarizes the existing MC fault diagnosis and fault-tolerant control strategy.Secondly,the topology of TSMC and its space vector modulation strategy are introduced.The operation mode of TSMC are analyzed under healthy and faulty Condition respectively.On the basis of these,the TSMC fault diagnosis method based on switch group error voltage is proposed,and this method can judge faulty switch group and locate the faulty switch of TSMC according to switch group error voltage.The proposed method has many advantages,such as independent of modulation strategy,fast detection,high efficiency,and less affected by the load and the outside noise disturbance factors.It also overcomes the shortcomings of the existing TSMC diagnostic method to detect the DC side voltage and increase the sensor,and reduces the cost of diagnosis system to some extent.Thirdly,based on the analysis of existing MC fault-tolerant control strategy,and combined with the characteristics of modulation strategy and topology structure of TSMC,this paper presents a fault-tolerant control method for TSMC topology base on a redundant bridge.Finally,the simulation model of fault diagnosis system and fault-tolerant control system of TSMC switch are established respectively in the Matlab/simulink simulation environment.The experiment system of fault diagnosis system is also established,and it is based on DSP and CPLD,which mainly includes main switch circuit,drive circuit and signal conditioning circuit,etc.The simulation and experiment resultsverify the validity and the feasibility of the fault diagnosis method and fault-tolerant control strategy.