A positionless method for low-speed operation of electrically excited doubly salient pole motors based on the slope threshold of series inductance

Abstract

The invention discloses an electro-magnetic double-salient-pole motor low-speed operation sensorless method based on series inductor slope threshold. The method includes: allowing the two-phase armature windings of an electro-magnetic double-salient-pole motor to be communicated simultaneously, allowing a switch tube to perform high-frequency chopping during low-speed operation, respectively detecting the bus current values during on and off of the switch tube, entering a digital controller to respectively calculate the bus chopping current slope value during on and off of the switch tube, calculating the current communicating series self-inductor slope value, judging the phase changing point by comparing the current communicating series self-inductor slope value with the preset motor phase change point series self-inductor slope threshold, and starting phase change when the series self-inductor slope value is smaller or equals to the preset threshold. By the method, the defects that the reverse potential cannot be detected directly during low-speed operation, an external circuit is needed, the phase change point position variation of the series self-inductors are difficult to detect, and the like are overcome. In addition, the method is simple and easy to implement, and the foundation for low-speed stable operation of the electro-magnetic double-salient-pole motor is laid.

Description

technical field [0001] The invention relates to a position sensorless control method for an electric excitation double salient motor, belonging to the technical field of electric excitation double salient motor control. Background technique [0002] The electric excitation double salient pole motor is similar to the switched reluctance motor. There are no windings and permanent magnets on the rotor, and the structure is simple. At the same time, the permanent magnet of the excitation winding is used on the stator to establish the main magnetic field. It has a good application prospect. [0003] As a novel motor control technology, position sensorless technology is widely used in the research of aerospace, industrial information and other fields. When the motor is running at low speed, the back EMF is not easy to collect. Therefore, the research on position sensorless technology at low speed needs to use other characteristics of the motor to accurately obtain the commutation...

AI Technical Summary

Problems solved by technology

[0008] Based on the traditional current response positionless method, combined with the driving circuit and electromagnetic characteristics of the electrically excited double salient pole motor, the present invention proposes a novel electrically excited double salient pole motor without position at low speed based on the slope threshold of the series self-inductance The sensor estimation method, the problem to be solved by this method is: to overcome the weakness that the back EMF cannot be detected when the electric excitation doubly salient motor is running at low speed, to avoid the problem of small changes in self-inductance at the commutation point, and to fully consider the inductance of the motor itself According to the law of slope change, a simple and easy-to-implement position sensorless control strategy is obtained. This method does not need to know the motor speed, which lays the foundation for the smooth operation of the electrically excited double salient motor at low speed.

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