Design Of Rotor Position Observer For Internal Permanent Magnet Synchronous Motor Without Position Sensor In Electric Vehicles Operating At Medium And Low Speed

Permanent magnet synchronous motor is widely used in industrial control systems such as new energy vehicles due to its small size,no excitation current,low loss and high power density.The PMSM vector speed control system must have high precision rotor position and speed parameters,and the position sensor(Hall sensor,rotary transformer)must be used to obtain the information of these parameters.However,the position sensor may fail in practice,resulting in failure and affecting system operation.Therefore,it is very important to study the sensorless position of PMSM vector control system as the redundancy of control system.At the same time,the position-free sensor system is also the current research hotspot.Combined with the actual project of Chery S61 new energy SUV electric vehicle,this project proposed the sensorless control system's rotating high-frequency voltage excitation injection method and the sliding mode observer's composite control algorithm,and realized the self-detection of rotor Angle position and speed in the sensorless middle and low speed range of IPMSM.An improved Luenberger observer and an improved rotor-salient pole tracking position estimation based on IIR digital filter are presented in this paper.FDA Tool design using MATLAB in infinite impulse response digital filter to get the high frequency current response,replaces the synchronous shaft high-pass filter filter,reduces the filter to extract the negative phase sequence of the influence of high frequency current excitation response phase,simplifies the rotor position and speed estimation process,aiming at the influence of filter on the rotor magnetic pole position estimation accuracy,put forward the corresponding linear phase compensation,avoid position estimation error in the system time delay increase,can effectively reduce the error of rotor position estimation.And Luenberger observer based on heterodyne method,the real time detecting of rotor position information,in the high frequency current component from the negative phase sequence to estimate the rotor position Angle and speed,in order to improve the steady-state performance of observer,the PID controller with integral gain,high frequency current signal after processed by the observer's integral action,the jamming signal greatly weakened.The simulation module of SENsorless vector control of PMSM was built in Simulink simulation.Compared with the traditional high frequency injection method,the improved algorithm can estimate the position of rotor magnetic pole more accurately and quickly in the sensorless control process of motor in the low speed range,and has better stability.Based on the current difference between the estimated current and the actual current,a sliding-mode observer is designed to detect the current difference in real time.In medium speed sensorless control,within the scope of the all-digital fuzzy sliding-mode observer method is used to implement Angle of rotor position and speed estimation,when the all-digital fuzzy sensorless operation in a low range,the high frequency voltage signal injection method to track the rotor magnetic pole position,make full use of the advantages of two kinds of control algorithm is realized accurately estimate the rotor position,in the low speed and medium speed of transition zone,introducing the linear weighted average algorithm,implementation is suitable for the low speed range of all-digital fuzzy composite sensorless control,through the MATLAB/Simulink simulation experiment,the results show that:Combined with the sliding mode observer method and the high frequency excitation injection method,the stability of the two control algorithms in the switching process is improved,and the sensorless smooth control of PMSM in the middle and low speed is effectively realized.