Three-phase Permanent Magnet Synchronous Motor Drive Tolerant To Open-phase Fault

The increasingly serious environmental pollution problem and the gradual depletion of non-renewable energy have accelerated the development of the global new energy vehicle industry,and the new energy vehicle is gradually replacing the traditional internal combustion engine vehicle.As one of the key components of new energy vehicles,the motor drive system’s safety and stability are very important to the driver’s property and life safety.Disconnection of the motor drive system will cause the fluctuation of three-phase current and torque,causing mechanical stress to damage the internal parts of the motor,reducing the control performance of the motor,and even burning the motor for a long time.Fault-tolerant control system can be fault-tolerant after the occurrence of a fault,to ensure that the system can reduce the stable operation,can better improve the reliability of the system.At present,the fault tolerant control method for the open circuit fault of PMSM drive system is mainly based on the combination of hardware redundancy and control algorithm,but this method will change the mechanical structure of power devices and other components,resulting in problems such as cost increase and drive system volume increase,so its universality is low.In this paper,a software fault-tolerant control strategy for single-phase discontinuance of three-phase PMSM is improved.Firstly,based on the equivalent circuit model of PMSM in the two-phase rotating coordinate system,the non-fault and fault mathematical models of PMSM are established and simulated.Based on the normal and fault operating conditions of permanent magnet synchronous motor,the parameters of three phase permanent magnet synchronous motor under two different operating conditions were simulated and analyzed,and the adverse effects of faults on the motor operation were obtained.Based on the analysis of the parameter changes before and after the failure of the motor drive system and the large change of the stator current before and after the failure,a fault diagnosis algorithm based on the error of the d-q axis stator current of the sampling interval before and after the failure was designed.Based on the motor torque formula,a fault-tolerant control algorithm was designed to control the torque through the stator current,and the reversing advance Angle was introduced to improve the fault-tolerant control.After the fault,the CHBPWM was adopted.Combined with the fault diagnosis algorithm,fault tolerant control algorithm and the mathematical model of fault and non-fault,the fault tolerant control simulation model of permanent magnet synchronous motor is established,and the feasibility and effect of the fault diagnosis algorithm,namely fault tolerant control algorithm,are verified by the simulation.In order to verify the principle overview and control strategy of this paper,an experimental platform for fault tolerant control of 4k W motor drive system is designed and built.The motor controller uses TI TMS320F28335 as the main control chip and IGBT as the power device.Based on the operation conditions of permanent magnet synchronous motor before and after the failure,the experiment compared the fault tolerant control motor running state and the change of parameters when the permanent magnet synchronous motor drive system occurs circuit failure.Comparison experiments show that the proposed fault diagnosis algorithm has shorter detection time,less computational power and stronger robustness compared with the existing methods.The fault-tolerant control algorithm proposed in this paper can realize the fault-tolerant control without changing the topological structure,and the pre-firing angle of reversing proposed in this paper can optimize the fault-tolerant control.