Speed sensorless starting method for synchronization motor

Abstract

The invention relates to a speed sensorless starting method for a synchronization motor. The method includes performing two processes of DC positioning before starting, applying id current in a 90-degree direction and a 0-degree direction separately, and applying iq current when starting, and performing closed-loop control on id and iq current at the same time; when the motor reaches a first switch rotation speed point, reducing the iq current gradually, keeping the id current unchanged, and comparing to obtain a difference value between an output angle and an open loop given angle of a flux observer; when the motor reaches a second switch rotation speed point, switching directly and entering into closed-loop control. According to the invention, new id axial current is introduced and a positioning effect is achieved for the motor. Smooth switching can be realized during the switching process of the motor. Besides, even a load has comparatively large fluctuation during the switching process, motor out-of-step can also be prevented. The method has excellent stability and switching quickness.

Description

technical field [0001] The invention relates to the field of motor control, in particular to a method for starting a synchronous motor without a speed sensor. Background technique [0002] After the permanent magnet synchronous motor (Permanent magnetic synchronous machine, PMSM) adopts sensorless control, coupled with the application of frequency conversion technology, it has excellent performance and has good application prospects in many fields. It is widely used in electric vehicles, industrial sewing machines, air conditioners, Applications such as elevators and higher-precision CNC machine tools and robots; the existing open-loop start-up method generally uses an iq current to drag the motor up. The deviation between the angle of the observer and the angle of the observer is switched when the deviation angle is small. However, if the driver turns the steering wheel during the switching process, the load torque may fluctuate, resulting in the risk of out-of-step, and a ...

AI Technical Summary

Problems solved by technology

[0002] After the permanent magnet synchronous motor (Permanent magnetic synchronous machine, PMSM) adopts sensorless control, coupled with the application of frequency conversion technology, it has excellent performance and has good application prospects in many fields. It is widely used in electric vehicles, industrial sewing machines, air conditioners, Applications such as elevators and higher-precision CNC machine tools and robots; the existing open-loop start-up method generally uses an iq current to drag the motor up. The deviation between the angle of the observer and the angle of the observer is switched when the deviation angle is small. However, if the driver turns the steering wheel during the switching process, the load torque may fluctuate, resulting in the risk of out-of-step, and a slower speed is required during the switching process. The speed reduces the iq current, making the switching time too long, resulting in slower startup speed

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