Novel permanent magnet synchronous motor position observation method with dynamic error compensation function

Abstract

The invention discloses a novel permanent magnet synchronous motor position observation method with a dynamic error compensation function, belonging to the technical field of self-sensing observation of the positions of synchronous motors. The novel permanent magnet synchronous motor position observation method with the dynamic error compensation function uses a sliding mode observer to estimate an equivalent electromotive force and extract a rotor position. A dynamic error compensator is adopted to suppress rotor position estimation errors caused by direct-axis current changes of the stator, and the position estimation performance of a sensorless direct torque control system of a salient pole permanent magnet synchronous motor is improved. Compared with an observer without the dynamic error compensator, an observer provided by the invention has the following advantages: (1) position observation precision in a fast torque response state, a rotating speed state and a load transient state is greatly improved; and (2) for direct torque control of high-harmonic current, the position observation precision in a stable rotating speed state is greatly improved by reducing observation errors caused by current harmonics.

Description

technical field [0001] The invention relates to the technical field of self-sensing observation of a synchronous motor position, in particular to a novel position observation method of a permanent magnet synchronous motor with dynamic error compensation. Background technique [0002] The permanent magnet synchronous motor has the advantages of simple structure, small size, low loss and high efficiency. It is widely used in industrial production, national defense, daily life and other fields. In the control system of the permanent magnet synchronous motor, it is essential to install a speed sensor or a position sensor on the motor shaft, which brings the following problems: (1) The sensor is affected by temperature, humidity, detection distance, vibration and other working conditions Influence, especially in some applications with high sensor detection accuracy, limits the application of PMSM speed control system in these special fields; (2) The sensor increases the size of ...

AI Technical Summary

Problems solved by technology

In the control system of the permanent magnet synchronous motor, it is essential to install a speed sensor or a position sensor on the motor shaft, which brings the following problems: (1) The sensor is affected by temperature, humidity, detection distance, vibration and other working conditions Influence, especially in some applications with high sensor detection accuracy, limits the application of PMSM speed control system in these special fields; (2) The sensor increases the size of the motor and increases the inertia of the control system; (3) In order to ensure the detection accuracy, the installation and maintenance of the sensor needs to be carried out at a high level, which increases the complexity of the drive system, reduces the reliability of the system, and increases the cost

Direct torque control has a fast dynamic torque response, resulting in a large d-axis stator current difference, but large stator flux distortion and torque ripple lead to large stator current subharmonics

Therefore, the position observation error caused by the d-axis stator current differential is relatively large when the direct torque control is running at a transient load and speed or at a steady speed

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