Research On Field Oriented Control Of High Speed Permanent Magnet Synchronous Motor Based On Hall Effect Sensor

With its excellent speed control performance,high power factor and energy-efficient,permanent magnet synchronous motor has been widely used in AC servo control.Accurate rotor position and speed information is the key to high performance PMSM field-oriented control.Optical Encoder and Resolver are commonly used in high precision position sensors.However,these mechanical sensors are costly and need to be mounted on the motor shaft,which undoubtedly increases the volume and moment of inertia of the entire system.And reduce the reliability and anti-interference ability of the system.Speed sensorless technology saves the cost of the system,but it has a large amount of calculation and is sensitive to the change of motor parameters.Therefore,the application and performance of speed sensorless technology still have considerable limitations.Compared with other position sensors,halleffect sensors are small in size,low in cost,simple in structure,and can adapt to various harsh environments such as oil pollution,especially in the high-speed motor stage.It is an excellent choice in low resolution position sensors.How to obtain continuous and high-precision rotor position from discrete rotor position information output by low-resolution hall-effect sensor becomes the key of PMSM field-oriented control technology based on hall-effect sensor.Firstly,based on the principle of field-oriented control,the mathematical model and coordinate transformation matrix of permanent magnet synchronous motor are deduced.Then,the classical dual-current flux-weakening control and single-current flux-weakening control principle of permanent magnet synchronous motor are studied.The control performance of the latter is verified on the PMSM experimental platform.A current regulator is omitted in the field-weakening control system based on single current regulator,which liberates the ability of the current regulator and improves the performance of the fieldweakening control system.An effective control scheme is established to verify the hall-effect sensor estimation method at high speed.In this paper,the principle and algorithm error of traditional linear interpolation estimation method are analyzed in detail,and the effectiveness of the algorithm is validated on PLECS simulation platform.The external error influencing factors of the rotor position estimation method based on hall-effect sensor are summarized,including the chattering of rotor shaft and the installation error of hall-effect sensor.Then the simulation results show that the estimation accuracy of the traditional estimation method is greatly reduced and serious rotor position jump phenomenon occurs after considering external errors.In this paper,the double curve fitting estimation method is proposed for the first time from the view of curve fitting.The least square method and Newton interpolation method are used to predict the next discrete position point and estimate the current position information.In order to suppress the errors caused by installation errors and shaft jitter,and obtain the continuous smooth position information of the rotor.The double curve fitting algorithm is written in CScript module of PLECS simulation platform.The weak magnetic field control model of single current regulator is built on PLECS simulation platform to verify the effectiveness of the algorithm.The rotor estimation errors are analyzed according to the waveform under the conditions of rising speed,falling speed and steady state operation respectively.The simulation results show that the new algorithm has high estimation accuracy,and eliminates the jump phenomenon caused by the force correction of rotor position angle in the traditional interpolation estimation method,and improves the control performance of PMSM.