Rotation speed estimation method for permanent magnet synchronous motor (PMSM) based on novel phase-locked loop

Abstract

The invention provides a rotation speed estimation method for a permanent magnet synchronous motor (PMSM) based on a novel phase-locked loop. The method comprises the following steps: obtaining back electromotive forces; smoothening a waveform through an extended Kalman filter for optimization, so that optimized back electromotive forces e<alpha> and e<beta> are obtained; and calculating an errorvalue according to the optimized back electromotive forces e<alpha> and e<beta> and inputting the error value into the novel phase-locked loop for speed estimation. The method has the advantages thatmultiple solutions are transformed into a single solution for adaptation to PI control, so that a rotation angle estimation value theta-arrow and a rotation speed omega-arrow can be more accurately calculated; and excellent sensorless control can be achieved, so that a rotation angle and a rotation speed signal can be accurately estimated even in case of a low speed or reversed rotation.

Description

technical field [0001] The invention relates to a method for estimating the rotational speed of a permanent magnet synchronous motor without a speed sensor based on a novel phase-locked loop. Background technique [0002] There is mutual coupling between the three-phase electricity of the AC motor, and it does not exist independently. Motor vector control refers to transforming the three-phase coordinates into a stationary αβ coordinate system and a rotating dq coordinate system to achieve decoupling, where the d-axis only provides a magnetic field and does not provide torque, that is, it does not do work. In the permanent magnet In the synchronous motor, the d-axis current is generally set to 0, because there is a permanent magnet, so there is no need to provide a magnetic field. Therefore, only by controlling the q-axis current, the magnitude of the torque, that is, the magnitude of the rotational force, can be controlled. According to Newton's second law, the force chan...

AI Technical Summary

Problems solved by technology

However, since the sliding mode observer method has strong chattering, how to extract the rotational speed signal from the huge noise caused by chattering is a very important issue

In the speed estimation based on the speed sensorless control of the back electromotive force motor, at low speed (the back electromotive force is very weak, easily affected by external interference and noise) and reverse rotation, the accuracy will drop or even be completely uncontrollable, resulting in inaccurate speed estimation. precise

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