Position sensor-free permanent magnet synchronous motor starting method

Abstract

The invention discloses a position sensor-free permanent magnet synchronous motor starting method. The method includes the steps of: 1. a two-time current injection method based on a current closed loop is adopted so as to ensure that an initial magnetic pole position of a permanent magnet synchronous motor is a 0-degree direction; 2. VF control is adopted in a low-speed part, a switching frequency is selected at low frequency, waiting for switching can be started till VF control runs to the frequency, and at the same time, a sliding-mode observer also starts to work; 3. through artificial setting, an active smooth switching strategy is adopted, so that the motor can automatically switch at low and intermediate speed switching positions; and 4. after success switching, a position sensor-free method is adopted to control operation of the permanent magnet synchronous motor in a closed-loop manner. The method has the advantage of enabling the position sensor-free permanent magnet synchronous motor to realize rapid and smooth starting at low speed without selecting VF parameters.

Description

technical field [0001] The invention relates to a permanent magnet synchronous motor technology, in particular to a starting method for a permanent magnet synchronous motor without a position sensor. Background technique [0002] The permanent magnet synchronous motor has the advantages of simple structure, small size, high power density, high efficiency, small torque ripple, and excellent control performance. Usually, the operation control of the permanent magnet synchronous motor needs the position sensor to detect the position and speed of the rotor. Traditional position sensors usually use mechanical position sensors such as incremental encoders, resolvers, Hall sensors, photoelectric code discs, etc. These sensors have many defects, not only complicated installation and debugging, but also increase the cost and volume of the motor, and It is easy to introduce interference signals, which reduces the reliability of the motor operation. [0003] In order to overcome the ...

AI Technical Summary

Problems solved by technology

These starting methods all use the voltage open-loop method to start the motor. The starting torque of the motor is greatly affected by the load, which may easily lead to the motor out of step; and no matter what the application is, this VF / IF method is used, so , when faced with applications that require relatively high VF parameters, the motor often cannot be switched or the impact is relatively large; in addition, in order to meet For low and medium speed switching conditions, the selection of VF parameters usually requires repeated debugging to obtain

Correspondingly, in industrial applications, when debugging different motors or load changes, it is often necessary to re-adjust VF / IF parameters to meet switching conditions, which makes on-site debugging more complicated, and the development cycle is long, resulting in a serious limitation of the actual application range

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