Research On Position Sensorless Control Of Permanent Magnet Synchronous Motor And Restart Problem With Speed

Permanent magnet synchronous motors have a wide range of applications in modern industrial production.Vector control needs to rely on accurate rotor position information to complete closed-loop control.Mechanical sensors have become a common way to obtain rotor position information,but what follows is a system with the decrease in reliability and the increase in cost,position sensorless control technology has become the focus of research nowadays.In applications such as electric locomotives,full-speed domain control is used,and frequent start-stops,accelerations and decelerations are required according to working conditions.From the perspective of engineering application,this paper conducts research on the position sensorless full-speed domain control of permanent magnet synchronous motors.The high-frequency pulse vibration square wave injection method combined with the Romberg observer method is used to construct a positionless control strategy.Two methods are adopted The method of weighting function is switched.The low-frequency sine wave injection method can be used to determine the rotor polarity in the rotating state,and the cumulative addition method can be used to compare the polarity to enhance the accuracy of the judgment.When the motor rotates freely,there is no current,and it needs accurate position and speed for non-position control when restarting.In this paper,the zero-voltage vector pulse short-circuits the non-inverting bridge arms of the three-way inverter,and the information of the motor speed and rotor position can be obtained from the short-circuit current.At low speeds,the short-circuit current is small,and the error of the current sensor will cause the estimation result to be biased.In this paper,the error analysis is carried out through mathematical derivation.On the basis of this theory,an estimation strategy of zero-voltage vector pulse method combined with high-frequency injection rotor position estimation method is constructed.By applying a zero-voltage vector before re-input,an appropriate rotor position estimation method is selected so that the motor can be re-input in the full-speed domain.This method has positive significance for improving the reliability and efficiency of engineering application systems.Finally,the article uses Simulink to build a permanent magnet synchronous motor simulation system to simulate and verify the proposed position sensorless full-speed domain control strategy and full-speed domain with-speed retransmission strategy.At the same time,a 14 k W permanent magnet synchronous motor towing platform is built.Experiments on the above strategy have verified the correctness of the principle and the feasibility of the algorithm.