Research On Permanent Magnet Synchronous Motor Vector Control System With Low-precision Position Sensor

With the increase of car ownership,the problems of oil consumption and air pollution are also increasing seriously,and it is necessary to develop the new energy vehicles,especially the electric cars.The low-speed electric cars have become one of the important directions for electric cars because of its low cost and convenient charging,while many high-end electric cars have been pushed to the market.The mainly drive motor of low-speed electric cars is brushless direct current motor(BLDCM),which has some weaknesses such as torque ripple and loud noise,accompanying with many advantages.Therefore,it is tendency to take the place of BLDC with permanent magnet synchronous mortor(PMSM).Here,the paper studies the vector control system of PMSM with Hall-effect sensors,aiming at improving the disadvantages of high-precision sensors and sensorless schemes.Firstly,this paper proposes the idea that replacing the BLDCM with PMSM in electric cars,after comparing these two types of motors in some aspects and analzing the features of vector control of PMSM.Secondly,the principle of Hall-effect sensor is interpreted,while some typical methods for estimating rotor position and their advantages and disadvantages are displayed.The scheme based on the orthogonal phase locked loop(OPLL)is shown,along with the adaptive notch filter.Some tactics are put forward to improve the shake of estimated velocity and angle,in addition,the progressive compensation are used to decrease the error between estimated position and actual position.Incremental proportion-integral adjuster is also adopted to realize the stable transition from starting with square wave to proposed scheme.Then,the types of Hall-effect sensor faults are divided by the amounts of faulted sensors,and they are distinguished by the different appearances of different faults.Corresponding fault-tolerant schemes are put forward to guarantee that motors can work within certain accuracy at the single-element faults and electric cars can stop to safe area at double-element faults.Finally,this paper comes up with a strategy to prevent car slide on ramp starting based on Hall-effect sensor which makes the sensors practical.The models based on MATLAB/Simulink are built for verifying the validity and feasibility of the proposed estimation and fault-toleran scheme,corresponding experiments are also carried out on the platform based on STM32F103 ZE.The simulations and experiments indicate the strategy employing two-phase orthogonal PLL can satisfy the requirement of rotor position estimation for PMSM.