Speed sensorless control method for motor with high precision and speed requirements

Abstract

The invention belongs to the technical field of motor speed control and relates to a speed sensorless control method for a motor with high precision and speed requirements. The speed sensorless control method comprises the steps of constructing a speed observer model by using an MRAS (Model Reference Adaptive System) principle; in order to utilize an SMC (Sliding Mode Control)-MRAS rotation speedidentification method, selecting a PMSM (Permanent Magnet Synchronous Motor) as a reference model and a stator current model as an adjustable model, and constructing a sliding mode surface S by usingoutput differences of the two models to improve the speed observation precision; meanwhile, replacing the conventional Sgn function with a Sigmoid function as a switching function in sliding mode control to establish a sliding mode observer model so that the system has better dynamic and static stability; then proving that the rotation speed observation method in combination with the MRAS and theSMC has strong robustness and good dynamic and static performance in the PMSM speed sensorless direct torque control system by changing the reference speed value and the load torque through operationsimulation of a Matlab / Simulink.

Description

Technical field: [0001] The invention belongs to the technical field of motor speed control, and relates to a speed sensorless control method for a motor requiring high-precision speed, in particular to the speed sensorless control of a permanent magnet synchronous motor (PMSM). Background technique [0002] The permanent magnet synchronous motor uses permanent magnets as the rotor to provide a rotating magnetic field without external excitation, and can obtain extremely high power density and torque / inertia. Permanent magnet synchronous motor has the advantages of low heat generation, simple structure, small volume and low noise, and has been widely used in small and medium-sized motion control systems, becoming an important field of research and application. The precise control of the permanent magnet synchronous motor needs to provide accurate rotor position and speed. Traditional rotor information collection is mostly through speed sensors, photoelectric encoders, resolv...

AI Technical Summary

Problems solved by technology

[0003] The general method of sensorless control is to use a speed sensorless model predictive torque control. Based on the model reference adaptive technology combined with the model predictive control strategy, an observer is designed to accurately estimate the rotor speed and reduce torque and stator flux fluctuations. Improve the dynamic and static response characteristics of the system; in addition, the use of speed observers or flux observers to increase state variables can also improve system stability. These two methods can achieve precise control when the motor is running stably, but in When the motor is just started or the running state changes, the above two methods cannot accurately estimate the running state of the motor in real time, and cannot achieve high-precision and stable control

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