Research On Fault Reconstruction Of Six-phase Permanent Magnet Synchronous Motor Based On High-order Sliding Mode Observer

With the development of power electronic devices and control theory,AC speed regulation technology develops towards high power.Six-phase permanent magnet synchronous motor has been widely used in transportation,aerospace and other fields due to its obvious advantages of low voltage,high power,low torque ripple and high fault tolerance.This makes the six-phase motor face a variety of complex and changeable environment,such as temperature,magnetic field,chemical corrosion or oxidation and other factors will affect the stability of the body.Therefore,in order to ensure the stable operation of the six-phase permanent magnet synchronous motor,the real-time reconstruction of the motor actuator and sensor fault has important theoretical and engineering significance.In this paper,the actuator and sensor fault reconstruction of six-phase permanent magnet synchronous motor is taken as the research object,and the high order sliding mode theory provide theoretical support to study the actuator and sensor fault reconstruction of six-phase permanent magnet synchronous motor.The main research of this paper is as follows:In order to reduced the chattering of conventional sliding mode observer,a permanent magnet demagnetization fault reconstruction method based on super twisting sliding mode algorithm was proposed for the permanent magnet demagnetization fault of six-phase permanent magnet synchronous motor under complex operating conditions.The simulation results show that,compared with the conventional first order method,the second order sliding mode observer based on the super twisting algorithm can accurately reconstruct the demagnetization fault and effectively reduce the chatter of conventional sliding mode.In order to improved the observer’s dynamic and static performance and isolated the influence of rotating speed on the observation accuracy,a permanent magnet demagnetization fault reconstruction method based on an improved second order sliding mode observer was proposed to solve the problem that permanent magnet is prone to demagnetization fault in a six-phase permanent magnet synchronous motor under complex operating conditions.The simulation results show that,compared with the conventional first order sliding mode and super twisting observer,the improved second order sliding mode observer can effectively reduce the chatter and suppress overshoot,and has stronger robustness.Aim at the problem that six-phase permanent magnet synchronous motor system for nonlinear current sensor fault,the design matrix transformation to decouple the sensor fault from the unknown input disturbance completely,the sensor fault of the nonlinear system is transformed into the actuator fault of the nonlinear system by introducing a low pass filter,and proposed super-twisting sliding mode luenberger observer to solved current sensor fault reconstruction method.By designing the observer for the sub-system and applying the sliding mode equivalence principle,the precise reconstruction of the fault can be realized,which can effectively suppress the chatter of the conventional sliding mode observer.