Research And Application Of Permanent Magnet Synchronous Motor Without Position Sensor Control On Electric Power-assisted Vehicles

An electric power-assisted vehicle is akin to a bicycle equipped with a power assist system that aims to aid the rider in accelerating,conquering hills,and reducing wind resistance.The core component of an electric power-assisted vehicle is the permanent magnet synchronous motor,whose performance has a significant impact on the overall efficiency of the vehicle.Curren tly,permanent magnet synchronous motors are the preferred choice for electric power-assisted vehicle motors due to their high efficiency,power density,accuracy,low noise,and long lifespan.Traditional control methods for these motors rely on mechanica l sensors to determine their position and speed.However,given the high cost and large size of such sensors,low-resolution Hall position sensors are commonly used as the primary sensor for motors in the electric booster field.This paper presents a novel approach to enhance the dynamic performance of electric power-assisted vehicles.The proposed method utilizes a sliding mode observer,which effectively addresses the issue of low-resolution Hall position sensors that often experience degraded accuracy at high speeds.This paper begins by deriving the motor model for a surface-mounted permanent magnet synchronous motor and providing an in-depth explanation of voltage space vector pulse width modulation.To meet the high-speed dynamic performance requirements of electric power-assisted vehicles,a position sensorless control algorithm based on the sliding mode observer method is employed.Furthermore,a Hall sensor-based starting scheme is utilized to ad dress the starting problem of the positionless control algorithm of the permanent magnet synchronous motor,achieving low-speed,high-precision Hall starting.A simulation of a positionless system for a permanent magnet synchronous motor is constructed usi ng MATLAB/Simulink to analyze rotor position and speed signals under various load conditions,thereby confirming the feasibility of the system.Additionally,a positionless sensor for a permanent magnet synchronous motor is built using Silan Micro’s SC32F5664 chip,including circuit design and software.Finall y,an experimental platform is established to test the performance of a permanent magnet synchronous motor without a position sensor in different states,such as starting,idling,loading,and stable operation,in order to verify that the system meets the requirements.The simulation and experimental verification confirm that the position sensorless permanent magnet synchronous motor contro l system proposed in this paper exhibits exceptional starting performance,fast response time,high estimation accuracy,and excellent operating efficiency.These results demonstrate the system’s reliability in the context of electric power-assisted vehicles.