Sensorless Vector Control Of PMSM For Electric Power Assisted Bicycle

Electric power assisted bicycle,as a healthy and environmentally friendly transportation that meets the needs of the general public,is well received by consumers.The driving motor is the core of the electric power assisted bicycle,and its performance directly affects the overall performance of the electric power assisted bicycle.In recent years,permanent magnet synchronous motor(PMSM)have become the first choice for electric power assisted bicycle industry due to its advantages of small size?low cost?high efficiency and simple control algorithms.In the traditional PMSM control,mechanical sensors are installed on the motor to obtain rotor position information and speed signal.However,mechanical sensors are costly and bulky.In the electric power assisted bicycle industry,low-resolution Hall position sensors are generally used to replace them.Aiming at the problems of low resolution hall position sensor in practical engineering applications,such as slow response speed and low estimation accuracy,this paper proposed a PMSM rotor position estimation algorithm based on Luenberger observer,and applied it to the control system of electric power assisted bicycle,which greatly reduced the production cost of electric power assisted bicycles and improved reliability.The specific research contents are as follows:Firstly,according to the structural characteristics of the selected surface-mounted permanent magnet synchronous motor,a mathematical model of the permanent magnet synchronous motor in a rotating coordinate system was established,and the working principle of the space voltage pulse width modulation(SVPWM)was described According to the performance requirements of electric power assisted bicycles,a sensorless control algorithm based on Luenberger observer was proposed.At the same time,combined with the start-up problem of PMSM applies to the sensorless control algorithm,the hall start-up scheme based on low-resolution hall position sensor was proposed.Then,using MATLAB/Simulink tools to build a simulation model of PMSM sensorless control system.In order to verify the feasibility of the control system,the rotor position and speed signals under load and no load are analyzed.And,based on the simulation model,the hardware circuit of PMSM sensorless control system was designed and the related software design was completed,so that it can meet the needs of electric mopeds.Finally,this paper proposed an experimental platform for PMSM sensorless control system of electric power assisted bicycle based on the PAC5232 chip which prcoduced by Active-Semi,and the starting process of the motor,the estimated speed experiment in no-load,the estimated position experiment in loading,and the stable operation experiment of the motor were analyzed experimentally.The simulation and experimental results show that the sensorless control system of the permanent magnet synchronous motor designed in this paper has a good start-up effect,can effectively improve the response speed and estimate accuracy of the system,and verify the reliability of the sensorless control system applied to electric power assisted bicycles.