Study On Fault Tolerant Operation Method Of Magnet Synchronous Motor Under Hall Signal Deviation/Fault Condition

Compared with DC motor,permanent magnet synchronous motor(PMSM)has many outstanding advantages,such as long service life,high power density and no spark in commutation,so it is widely used in civil electrical equipment,industrial automation manufacturing,vehicle transportation and so on.In the daily transportation,two wheeled electric vehicle is essential.Discrete Hall sensor is used as the rotor position sensor of permanent magnet synchronous motor in electric vehicle.From the early square wave control,it has gradually developed into the vector control with greater control flexibility and less running noise.However,the installation deviation and failure of Hall sensor are common in actual operation,which directly restrict the control effect and the service life of the control system.This thesis studies the fault-tolerant operation method of PMSM under the condition of Hall signal deviation / fault from three aspects,and fully considers the market acceptance and the demand of practical application,so that the research results can be realized on the low-cost control chip.The details are as follows:Aiming at the problem of installation deviation of Hall sensor,this thesis first analyzes the installation mode of Hall sensor in permanent magnet synchronous motor,introduces two estimation methods of rotor angle based on Hall sensor,average speed and average acceleration,and obtains the influence of installation deviation of Hall sensor on motor operation.Then,an angle compensation method based on least square method is proposed to compensate the absolute and relative position deviation of Hall sensor.Finally,the effectiveness of angle compensation is verified by simulation.Aiming at the problem of Hall sensor fault and incomplete fault,this thesis first introduces the traditional 60° average speed angle estimation method,studies the effectiveness of angle estimation under single-phase Hall fault and two-phase Hall fault,and analyzes the traditional fault-tolerant control method.Then,according to the problems existing in the traditional methods,a novel 120° average speed estimation method is proposed,so that the same estimation method can be used in normal Hall,single-phase Hall fault and two-phase Halls fault.Then,according to the new estimation method,the correction method of Hall angle estimation in sector switching is analyzed,and the traditional fault classification method is further simplified,so that the number of fault classification is less and the fault judgment is more accurate.Furthermore,according to the new estimation method,a Hall position signal generator is proposed to reconstruct the Hall signal,and the angle is estimated according to the absolute position and period of the Hall.Finally,the Hall vector fault-tolerant controller system is constructed,and three kinds of experiments are carried out on the experimental platform,which are the start-up experiment when the Hall has failed,the Hall sudden failure experiment when the hall is running normally,and the Hall signal recovery experiment when the fault-tolerant control is running normally.Aiming at the problem of Hall sensor complete failure,this thesis studies the problem of redundant control,namely dual-mode control.Firstly,this thesis introduces the definition of dual-mode control from the aspects of practical engineering application and academic research,and determines the dual-mode control method of implementing vector control based on Hall sensor when the Hall is normal or not completely damaged,and implementing sensorless square wave control based on phase voltage sampling when the Hall is completely damaged.Then,according to the hardware requirements of dual-mode control,from the perspective of low cost and compatibility,the design methods of voltage sampling circuit and current sampling circuit are analyzed,and an improved circuit is proposed for the delay problem of phase voltage sampling circuit.Finally,the switching condition and logic of dual mode are analyzed.After the above research and analysis,the wheel type permanent magnet synchronous motor is used as the control object,and the low-cost STM32F030 is used as the main control chip to build the experimental test system.Firstly,the basic performance of the controller is verified on the dynamometer platform.The experimental results show that the controller can meet the requirements of the national standard electric vehicle controller,and the motor output efficiency also reaches the design value.Then,the indirect experiments verify the effectiveness of the proposed Hall mounting error compensation,which can improve the maximum efficiency of the motor output.Finally,in the dual-mode switching experiment,the accuracy and smoothness of the dual-mode control switching are verified.