Study On Fault Diagnosis Of Power Converter In Switched Reluctance Drive System

Switched reluctance motor(SRM)offers several advantages such as simple structure,high efficiency,strong fault tolerance,and good speed regulation performance,making it widely used in various high-reliability applications.However,the power converter,as a critical component of the switched reluctance motor drive system,plays a key role in energy transfer and is also one of the weakest links in the system.Therefore,research on the fault diagnosis of power converter in switched reluctance motor drive system is particularly important.In this paper,a simulation model of a switched reluctance motor drive system is built,with a four-phase 8/6-pole switched reluctance motor and its asymmetric halfbridge power converter as the research object.Firstly,the spectrum analysis of the phase current is carried out by fast Fourier transform,and a diagnostic method of the main switch tube open circuit and short circuit fault of the power converter is proposed based on the change of the amplitude of the fundamental component of the current and the DC component.On this basis,a power converter fault diagnosis method based on the bus current and any one of the phase currents is proposed.The fault occurrence and fault type are determined by the spectral characteristics of the bus current,and the phase angle relationship between the fundamental component of the bus current and the fundamental component of any phase current is used as the basis for fault phase location.The short-circuit fault phase location problem is solved by combining it with the previous method.The diagnosis of open-circuit and short-circuit faults in fourphase switched reluctance motor power converter is achieved under the condition that only two currents are detected.Secondly,this paper analyzes the waveform change characteristics of each phase current after the fault,and proposes a power converter fault diagnosis method based on current average analysis by using the average value of phase current as the open-circuit fault characteristic and the symmetric relationship of each phase current average as the short-circuit fault characteristic.Finally,the corresponding fault diagnosis system is built in the simulation model of switched reluctance motor drive system according to the designed fault diagnosis scheme.The effectiveness and reliability of the above method are verified by the results of characteristic value calculation and fault diagnosis.