Research On Sensorless Control Technology Of Three-phase Permanent Magnet Synchronous Motor

Permanent magnet Synchronous Motors(PMSM)are widely used in AC drive systems due to their high efficiency and high power density.Due to the many disadvantages of mechanical sensors,position sensor is a research hotspot in recent years.At present,the control method for high-speed operation of the motor is studied extensively,and the control strategy when the motor is at a low speed is studied relatively little,so the sensorless control at low speed needs to be studied.This thesis uses a surface-mounted permanent magnet synchronous motor as a carrier to study the sensorless control of the motor at low speed or zero speed.The rotor position and speed detection scheme based on pulsed high frequency voltage injection method is given and the sliding mode is designed.The controller optimizes the system,discusses the factors that affect the accuracy of position estimation,and proposes improvements.First,elaborated the topic background and significance,introduced the development course of the ac(alternating current)theory and sensorless control of permanent magnet synchronous motor technology development present situation,has carried on the brief summary of various sensorless control technology,which leads to the main research content of this article.Secondly,the structure of the PMSM is analyzed,and the mathematical model of the PMSM and the transformation relationships between the voltage,flux,and torque in different coordinate systems are established.The basic principles and implementation methods of the space vector pulse width modulation are described and constructed.Position sensor permanent magnet synchronous motor vector control system,and simulation verification.Thirdly,the pulsed high-frequency voltage injection method was studied.The mathematical model and response current of PMSM at high frequency injection were deduced.The rotor position observer was designed to solve the rotor position and velocity at low or zero speed.Detection problem.Aiming at the problem of rotor initial position detection of permanent magnet synchronous motor,a new method based on SPMSM stator saturation saturation saliency detection initial position detection is proposed,which can facilitate the initial position estimation.According to the block diagram of the PMSM sensorless control system based on pulsed high-frequency voltage injection,the simulation model of the system is established and the simulation research is carried out.The simulation results agree with the theoretical analysis.Aiming at the problems of poor robustness,weak anti-jamming capability,and being easily affected by other factors,the PI controller uses the advantages of sliding mode control to design an integral sliding mode speed controller and apply it to pulse-based high In the sensorless control system of the permanent magnet synchronous motor with frequency voltage injection,the problem of large system overshoot,slow response,and curve jitter is significantly improved.Finally,the influence of several factors on rotor position estimation is analyzed in order to improve the accuracy of rotor position estimation.In power devices nonlinear effect on the influence of the rotor position estimation,the research is mainly focused on the inverter of the dead zone effect,and phase voltage compensation method is presented to improve the estimation precision of sensorless control position,the simulation proves that this method is feasible.At the same time,also analyzed the high frequency injection voltage frequency and amplitude of the rotor and the influence of the estimation error is,to filter are analyzed theoretically,the influence of the right frequency filter is given.