Research On The Sensorless Control Of PMSM In Full Speed Range

Permanent Magnet Synchronous Motor(PMSM)has been applied in many fields in recent years due to its series of advantages such as high power density,fast response and superior control performance.The control strategy used in this paper is a vector control strategy.The traditional vector control needs to obtain the corresponding position information through the position sensor to complete the closed-loop control.However,since the conventional position sensor has a series of disadvantages such as high cost and poor reliability,the current and voltage signals are used to estimate the rotor position angle of the motor.The algorithm has been paid more and more attention.After comparing the sensorless control methods,the control method of sensorless control of permanent magnet synchronous motor in full speed range combining I/f flow frequency ratio open loop start and interference observer based is designed.The main contents of this paper are as follows:1.The mathematical model of permanent magnet synchronous motor is established.Based on the vector control strategy,two methods for initial positional positioning of permanent magnet synchronous motor are studied.Pre-positioning method and basic voltage vector pulse injection method are designed.Control the model and use Matlab simulation to verify the accuracy of this method.After the initial position is determined,the I/f open-loop starting strategy is proposed.The accuracy of this method is verified by Matlab simulation.Finally,when the motor starts successfully in the zero-low speed range,a method of smooth switching to medium-high speed closed-loop control is proposed.2.In the sensorless control in the medium and high speed range,a sensorless control method based on the disturbance observer to estimate the extended back electromotive force is proposed.This paper introduces the disturbance observer based on the hidden polar machine and the salient machine,and infers the equation of the disturbance observer.After using the disturbance observer to estimate the extended back EMF,a PLL phase-locked loop speed estimator for the hidden pole machine and an adaptive speed estimator for the salient machine are designed.Finally,Matlab simulation is used to simulate under constant torque conditions and sudden torque conditions.3.Inferring the non-ideal factors affecting the estimated angle under the hidden polar machine and the salient machine,the factors influencing the position estimation based on the correlation derivation of the pole configuration of the disturbance observer can be derived:the observer gain,the rotational speed,the stator resistance and Inductance,and derive the specific impact of changes in these factors on position estimation.And use Matlab simulation platform to use the previously verified control model to explore and draw corresponding conclusions.4.Using the permanent magnet synchronous motor hardware experimental platform to verify the sensorless models derived above under different loads,and to explore the variation of the angular error of the two models under different load conditions.At the same time,also for the observer gain.Rotating speed.The non-ideal factors such as stator resistance and inductance are used to experimentally investigate the influence of position estimation,and verify the conclusions obtained earlier.