Brushless direct current motor sensorless control method based on sliding mode observer

Abstract

The invention discloses a brushless direct current motor sensorless control method based on a sliding mode observer. Firstly, a motor is started through a three-section starting technology, after a system is stabilized, brushless direct-current motor sensorless closed-loop control based on a sliding-mode observer is switched in, the sliding-mode observer is used for observing back electromotive force, then motor rotor position and rotating speed information is obtained, six-path commutation signals of an inverter are obtained by inquiring a commutation table, and the motor rotor position and rotating speed information is obtained. After passing through a driving circuit, the signals are sent into an inverter, a motor is driven to operate in a pairwise conduction square wave control mode, and meanwhile, the direct current bus voltage of the inverter is controlled by a rotating speed outer ring PI controller. According to the brushless direct current motor sensorless control method, a continuous and smooth hyperbolic tangent function is adopted to replace a sign function of a traditional sliding mode observer, the system buffeting phenomenon caused by switching time and space lag is weakened, a low-pass filter is omitted, and the robustness of the system is enhanced.

Description

technical field [0001] The invention relates to a position sensorless control method of a brushless direct current motor based on a sliding mode observer, belonging to the field of motor drive and control. Background technique [0002] Because brushless DC motors have the advantages of long life, low noise, and high efficiency, most of the laboratory stirrers produced by enterprises in the market now use brushless DC motors, and the performance of the stirrers using DC brushless motors is relatively stable. The control method Simple. But the traditional brushless DC motor needs an additional position sensor to provide the necessary commutation signal to the inverter, but the existence of the position sensor brings a lot of defects and inconvenience to the application of the brushless DC motor. Firstly, the position sensor will increase the volume and cost of the motor; secondly, the position sensor with many connections will reduce the reliability of the motor operation, an...

AI Technical Summary

Problems solved by technology

Among them, the back EMF method is the most widely used method, but it is difficult to obtain the back EMF of the brushless DC motor, and in order to ensure the correct current commutation, the phase shift needs to be compensated, which increases the control complexity

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