A Positionless Control Method of Permanent Magnet Motor Based on Back EMF Observer

Abstract

The invention discloses a positionless control method of a permanent magnet motor based on a counter electromotive force observer. By improving the structure of the observer, the observer has good selectivity to the back EMF signal. The back EMF observer has strong robustness to both high-frequency and low-frequency disturbances. The position angle and speed information can be obtained from the observed back electromotive force through the phase-locked loop, and the start-up phase is started by I / F. The positionless control method of the permanent magnet motor based on the back EMF observer avoids the installation of the position sensor, reduces the cost, improves the estimation accuracy of the position angle and speed, and improves the robustness of the control system. The back EMF observer solves the contradiction between the cut-off frequency and the phase angle delay of the traditional back EMF observer. Compared with the traditional back EMF observer, the required back EMF fundamental wave component can be better estimated.

Description

technical field [0001] The invention relates to a positionless control method of a permanent magnet motor based on a back EMF observer, which is suitable for situations where the installation cost of position sensors such as rail transit, aerospace, and electric vehicles is high or cannot be installed. Background technique [0002] Permanent magnet motors have the advantages of high efficiency, simple structure and low cost. It has very broad application prospects in the fields of aerospace, wind power generation, logistics transportation and electric vehicles. In the permanent magnet motor drive control system, accurate position and speed information is essential. But the installation of the position sensor increases the cost, increases the weight, and reduces the reliability of the control system. At the same time, the installation of position sensors is also restricted in some harsh environments. The use of positionless control can reduce costs, reduce system complexit...

AI Technical Summary

Problems solved by technology

However, the reduction of the cut-off frequency will bring a large phase angle delay, which is difficult to compensate

At the same time, in addition to high-frequency noise, DC bias is generally unavoidable when measuring phase voltage and phase current with sensors

The DC bias of the observer input voltage and current will also deteriorate the estimation of the back EMF and reduce the position accuracy of the estimated angle

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