Fault-Tolerant Control Of Current Sensor And Demagnetization Of PMSM Based On Equivalent-Input-Disturbance

With the rapid development of industrial automation,permanent magnet synchronous motor for industrial drive systems have attracted widespread attention due to their high power density,small size,large output power,and strong overload capability.The application environment of permanent magnet synchronous motor is very harsh,often affected by vibration shock,high temperature,dust and other factors.These factors may induce the failure of the motor and its drive system.If these faults cannot be dealt with in time,the faults will further expand,and even lead to the collapse of the entire system,resulting in huge losses.In order to ensure that the system can still operate stably and reliably after the permanent magnet synchronous motor fails,this thesis takes the current sensor fault and permanent magnet demagnetization fault of the permanent magnet synchronous motor as the research objects.The fault-tolerant control of current sensor and demagnetization fault of permanent magnet synchronous motor is studied by using equivalent input disturbance theory.The main research contents are as follows:Aiming at the performance degradation of permanent magnet synchronous motor drive system caused by the fault of current sensor,an improved equivalent input disturbance method based on sliding mode observer is proposed to suppress the fault of current sensor of permanent magnet synchronous motor drive system.Firstly,a system model including current sensor faults is constructed using the equivalent input disturbance in the control input circuit.Then an improved sliding mode observer is designed to estimate the equivalent input fault,and the influence of the fault on the system is suppressed based on the equivalent input disturbance theory.Meanwhile,the stability of the system is analyzed,and experiments are carried out based on the RT-LAB hardware-in-the-loop simulation platform.Finally,the effectiveness of the proposed method is verified by the experimental comparison of different methods.Aiming at the problem that the control performance is degraded due to the permanent magnet demagnetization fault of the permanent magnet synchronous motor,a fault-tolerant control method based on an improved equivalent input disturbance is proposed.First,the mathematical model of permanent magnet synchronous motor permanent magnet demagnetization fault is established.Then,the model is described by the equivalent input demagnetization on the control input channel,the super twisting sliding mode observer is used to replace the Luenberger observer in the traditional equivalent input disturbance method,and the improved equivalent input disturbance estimator is formed by combining with the filter.Estimate the demagnetization fault that occurs,and introduce the estimated equivalent input demagnetization fault into the control input end of the system,so as to eliminate the influence of the demagnetization fault on the system.The stability of the whole system is analyzed and proved,and three different methods are compared by using RT-LAB hardware-in-the-loop simulation platform.The experimental results of the three methods show that the proposed method can improve the dynamic response while maintaining the robustness of the permanent magnet synchronous motor drive system,and has a fault-tolerant control function for the permanent magnet demagnetization fault.