Permanent magnet synchronous motor torque control method based on sliding mode flux linkage observer

Abstract

The invention discloses a permanent synchronization motor torque control method based on a sliding mode flux linkage observer. Direct torque control is performed on a permanent synchronization motor through a 3 / 2 coordinate conversion module, the sliding mode flux linkage observer, an electromagnetic torque calculation module, a rotating speed PI adjustor, a torque PI adjustor, a flux linkage self-adaptation module, an expected voltage calculation module, an SVPWM module and an inverter. The sliding mode flux linkage observer is adopted for estimating the size, phase and rotator speed of stator flux linkage, and set torque is processed through the flux linkage self-adaptation module to obtain a set value of the stator flux linkage. Expected voltage calculation is performed on size and phase estimation values and the set value of the stator flux linkage and the output quantity of the torque PI adjustor, so that two-phase alternating-current voltage reference values on a two-phase static coordinate system are obtained, and then through SVPWM conversion, a switching signal is obtained to drive the voltage source inverter to achieve direct torque control over the permanent synchronization motor.

Description

technical field [0001] The invention belongs to the field of permanent magnet motor control, in particular to a permanent magnet synchronous motor torque control system based on a sliding mode flux observer. Background technique [0002] Permanent magnet synchronous motors have the advantages of small size, high efficiency, easy maintenance and strong adaptability to the environment, and are widely used in many high-performance drive fields. Direct torque control has attracted much attention because of its fast torque response, simple system structure and strong robustness to parameter changes. The stator flux linkage needs to be obtained in the direct torque control of the permanent magnet synchronous motor, and the accuracy of the flux linkage signal determines the control performance of the system. Therefore, how to accurately observe the stator flux linkage is particularly important for the high-performance permanent magnet synchronous motor direct torque control speed ...

AI Technical Summary

Problems solved by technology

However, in the voltage model, due to the integration of the back EMF of the stator winding, when the motor is running at low speed, the estimation accuracy of the stator flux linkage is seriously reduced, and even the system cannot work; in the current model, the rotor position needs to be known, adding additional position sensor, which will increase the cost of the control system, reduce the reliability of the system, and also limit the use of permanent magnet synchronous motors

In addition, in the direct control of the traditional hysteresis comparison, there are still shortcomings such as large torque and flux linkage fluctuations, and the switching frequency is not fixed. Moreover, when the motor is running at no load, reactive current is introduced, which leads to a decrease in the power factor of the motor.

Images