Research On Control Strategy Of Permanent Magnet Synchronous Motor For Electric Vehicle

The permanent magnet synchronous motor(PMSM)has the advantages of easy speed control,large torque at low speeds and wide speed operation range,etc.Therefore,it has a wide range of applications in electric vehicles.This paper takes PMSM as the research object,analyzes and studies the control strategy of PMSM of electric vehicles,so as to improve the running performance of electric vehicles.First,the research background and significance of the subject are mainly described,the structure of the PMSM and the mathematical model in each coordinate system are introduced and the commonly used coordinate transformation is derived.Then,the principle and implementation method of SVPWM technology are studied,which lays the basis for realizing the control algorithm of PMSM.Secondly,in view of the problems such as increased cost,volume,inertia,wiring complexity,low reliability and environmental disturbance caused by the installation of sensors for PMSM,the sensorless technology is studied.Including sliding Mode observer algorithm which estimates the rotor position and speed by observing the electromotive back force.The adaptive model reference algorithm is also included,the motor control system is used as the reference model,the current estimator model is used as the adjustable model,and the Popov superstability criterion is used to determine the parameter adaptive law to estimate the rotor position and speed.At the same time,the pulsating high-frequency voltage signal injection method is studied and the rotor position tracking observer method is used to estimate the rotor position.Finally,sliding mode observer control algorithm and pulsating high-frequency voltage signal injection method are combined to realize sensorless control of the motor running at full speed.Thirdly,according to the commonly used id=0 control algorithm and the maximum torque per Ampere(MTPA)control algorithm in the base speed range of the interior permanent magnet synchronous motor(IPMSM)commonly used in electric vehicles,the control performance is compared and analyzed and MTPA control algorithm using a direct formula calculation method is proposed to verify to be superior in control performance;at the same time,in the medium and high speed stage,the output capability of the MTPA control algorithm and i_d=0 control algorithm is verified to be insufficient by setting the simulation conditions.Finally,in view of the fact that the motor cannot continue to increase its speed when it runs to high speed,MTPA cannot effectively track the speed,the voltage feedback advanced angle field weakening control algorithm is combined with the MTPA control algorithm within the base speed range to achieve smooth switching with the base speed and expand the motor speed range.Finally,the hardware and software design of the vector control system of a PMSM is carried out and the experimental results are obtained.Moreover,the graph of data curve observation function of CCS software is used to observe and analyze the torque waveform of speed which proves the feasibility of the designed double closed loop vector control algorithm.