A speed control method of a permanent magnet synchronous motor without a position sensor

Abstract

The invention discloses a rotating speed control method of a permanent magnet synchronous motor without a position sensor and belongs to the field of synchronous motors. The method comprises a stepof setting a q-axis current reference value and a d-axis current reference value through a frequency converter when the permanent magnet synchronous motor starts to run, a step of running a slide modeobserver to perform speed estimation tracking on a motor rotor, a step of collecting a d-axis current real-time value of the permanent magnet synchronous motor, a step of judging whether the slide mode observer converges, and a step of stopping the speed estimation tracking when the slide mode observer converges, obtaining a speed estimation value at a stop speed estimation tracking time, and adjusting the speed of a motor rotor to a target speed based on a speed estimation value at the time that the speed estimation tracking is ended according to a preset acceleration. The problem that the acceleration starts from zero when a permanent magnet synchronous motor is started at present and the impact on the motor is large is solved, and the effects that the permanent magnet synchronous motorwithout the position sensor can be started to run in any state, the start speed is fast, the start is soft, and the motor is not impacted.

Description

technical field [0001] The embodiments of the present invention relate to the field of synchronous motors, in particular to a method for controlling the speed of a permanent magnet synchronous motor without a position sensor. Background technique [0002] The permanent magnet synchronous motor has the advantages of high power density and high efficiency, and is widely used in the field of servo control. In order to ensure the stable operation of the permanent magnet synchronous motor, the position sensor is generally used to detect the rotor position and real-time speed of the motor. However, in some special occasions, it is necessary to use a permanent magnet synchronous motor without a position sensor. In synchronous motors, a sliding mode observer is generally used to observe and calculate the position of the motor. [0003] When the frequency converter or servo driver controls the permanent magnet synchronous motor without position sensor to drive the fan or the large i...

AI Technical Summary

Problems solved by technology

[0004] In the existing technology, since the permanent magnet synchronous motor without position sensor has no speed tracking function, when it needs to be started again, one method is to start directly and accelerate from zero speed, but this will bring great harm to the motor or production equipment. Big shocks, another way is to wait for the rotor to come to a complete standstill before starting, but it takes a very long time

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