A position sensorless method for low-speed operation of electrically excited doubly salient motors based on terminal voltage

Abstract

The invention discloses an electro-magnetic doubly-salient-motor low-speed operation non-position sensor technique based on terminal voltage thresholds. According to the characteristics that two-phase armature windings of a three-phase electro-magnetic doubly-salient-motor are simultaneously communicated, and when the motor is at a low speed, high frequency chopping is carried out through switch tubes, the value of the terminal voltage of any non-communicated phase is detected when the two currently communicated switch tubes are turned on and turned off, a digital controller is accessed, and a phase change point is judged in the mode that the terminal voltage of any non-communicated phase when the switch tubes are turned on is subtracted by the terminal voltage of any non-communicated phase when freewheeling of a diode is carried out and the operation result is compared with a threshold of a zero point. The method overcomes the defects that when the motor operates at a low speed, counter electromotive force cannot be detected and an external circuit needs to be connected, complicated algorithms for calculating inductance constantly are eliminated, waveform non-sine is eliminated, an non-position sensor control strategy which is easy and convenient to achieve is obtained, and the technique lays a foundation for low-speed stable operation of the electro-magnetic doubly-salient-motor.

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] Electric excitation double salient pole motor combines the advantages of permanent magnet motor and switched reluctance motor. There is no winding and permanent magnet on the rotor, and the structure is simple. At the same time, the excitation winding is used to replace the permanent magnet on the stator to establish the main magnetic field. Widely used in military, new energy and other occasions. As a novel motor control technology, position sensorless technology is widely used in the research of aerospace, industrial information and other fields. The research on the low-speed position sensorless technology is mainly to use other characteristics of the motor to accurately obtain the commutation point under the condition that th...

AI Technical Summary

Problems solved by technology

[0005] Based on the traditional resistance sampling terminal voltage method, the present invention proposes a novel position sensor-less estimation method for electrically excited double salient pole motors at low speed based on terminal voltage thresholds in combination with the electromagnetic characteristics of electrically excited double salient pole motors. The problem to be solved by the method is: to overcome the shortcomings of the traditional positionless methods that require current sensors to sample and respond to the current to realize the position judgment, and strong interference, and to overcome the disadvantages of being unable to detect the back EMF when running at low speed and requiring an external circuit, etc., to obtain a The simple and easy-to-implement position sensorless control strategy lays the foundation for the low-speed and stable operation of the electric excitation double salient pole motor

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