Research On Fault Diagnosis And Fault Tolerant Control Of Permanent Magnet Synchronous Motor Drive System

Permanent Magnet Synchronous Motor(PMSM)drive system has the advantages of high work efficiency,large torque ratio and small size,and is widely used in aerospace,industrial production,electric vehicles and other fields.During the operation of the permanent magnet synchronous motor drive system,various faults will inevitably occur.Whether the motor body fails or the inverter fails,it will cause system instability.The fault diagnosis and fault-tolerant control of the permanent magnet synchronous motor drive system are effective approaches to improve the operation stability of the drive system.Taking the three-phase permanent magnet synchronous motor as the research object,the fault diagnosis and fault-tolerant control research are carried out for the common inter-turn fault problems of the motor.First,analyze the basic structure and working principle of the permanent magnet synchronous motor,establish the mathematical model of the motor system in the abc coordinate system and the dq coordinate system,and establish the short circuit between A phase by introducing a short circuit branch into the A phase.Furthermore,analyze and calculate the stator winding resistance and inductance parameters after the fault,and use the third harmonic as the characteristic quantity to characterize the inter-turn fault of the motor.Then,a fault diagnosis strategy based on the third harmonic is designed.The third harmonic exists in the back electromotive force of the motor.To extract the third harmonic of the motor,the linear extended state observer(LESO)in the Linear Active Disturbance Rejection Control(LADRC)is used.To observe the back electromotive force of the motor,use the Second Order Generalized Integrator(SOGI)to separate the fault characteristic quantities in the motor;eliminate the noise pollution in the third harmonic of the fault characteristic quantities through two filtering,and set up appropriate threshold value to realize the fault diagnosis;finally,the fault diagnosis strategy is simulated by Simulink to verify the feasibility of the strategy.Finally,a fault-tolerant control strategy for the faulty motor is designed.By removing the faulty phase,the short-circuit fault is transformed into an open-circuit fault,and the fault-tolerant topology of the three-phase four-arm fault is used to control the fault of the motor.In order to enable the magnetomotive force to form a vector circle during fault-tolerant operation of the motor,a fault-tolerant voltage space vector pulse width modulation(Space Vector Pulse Width Modulation,SVPWM)adjustment strategy is designed,and according to the motor fault mathematical model,design the fault-tolerant control strategy based on the zero axis voltage compensation.The linear auto disturbance rejection technology is used to design the auto disturbance rejection controller to suppress the torque ripple of the motor.Simulink is used to simulate the fault-tolerant strategy to verify the feasibility of the strategy.