Research On PMSM Speed Sensorless Control Technology For Vehicles

In the face of multiple crises in energy and environment,the development of high-performance electric vehicles has become the development goal of the automotive industry.The core part of electric vehicles is the electric drive system.Permanent magnet synchronous motors(PMSM)have become the mainstream choice of electric vehicle drive motors with their advantages of high efficiency,energy saving,good starting performance,and high power density.In high-performance speed regulation systems,mechanical sensors are usually used to detect the rotor position and speed of the drive motor.The installation of mechanical sensors has the following shortcomings,increasing the volume,increasing costs,and reducing system reliability.Therefore,it is of great significance to apply speed sensorless technology to PMSM control.Firstly,the mathematical model of PMSM in different coordinate systems is established,and different vector control strategies are summarized and compared.The i_d=0 control strategy is adopted,and the parameters of current regulator and speed regulator are adjusted to build a vector control system simulation model.Secondly,for the speed sensorless control method of pulsating high frequency signal injection method,the estimation accuracy is reduced at medium and high speeds,and the dynamic performance is poor.At this time,the motor back EMF is large,and the speed sensorless control of the fundamental wave model is good.The Model Reference Adaptive Method(MRAS)is applied to the medium and high-speed operation of PMSM.Aiming at the problems of large estimation error and poor robustness of the traditional MRAS method when the motor is started.Use the sliding mode variable structure control idea to improve the traditional MRAS control method.The new saturation function Sigmoid is used to replace the traditional switching function in variable structure control,the sliding mode variable structure MRAS speed identification system is designed,and an improved simulation model is built.Compared with the traditional MRAS control method,the improved speed is verified the identification system improves the estimation accuracy of rotor position and speed.Thirdly,aiming at the problem that the speed sensorless control method of the fundamental wave model fails at zero and low speeds,the pulse high frequency injection method is used to solve the problem.The rotor estimation principle of pulsating high-frequency voltage injection method is explained,the mathematical model of PMSM under high-frequency excitation is derived,the position tracking observer is designed,the simulation model of the control system is built,and the feasibility and effectiveness of the control method are verified.Finally,in view of the shortcoming that the above control method is only applicable to a single speed range,a composite control algorithm is given,which uses a weighted function to realize the smooth switching between the improved MRAS control method and the pulsed high frequency voltage injection method,and realizes the smooth switching in the full speed range.Sensorless control of PMSM.A simulation model of the control system was built on the Matlab platform to verify the effectiveness of the compound control method.Figure[56]table[7]reference[79]...