Control Method of Brushless DC Motor
Mar 19, 2019
Brushless DC motor control has three types: position sensor, sensorless and intelligent control.

1. Position sensor control.

Position sensor control is to install position sensor on the stator of brushless DC motor to detect rotor position and control stator winding commutation. The position sensors used are electromagnetic type (such as reluctance rotary transformer), photoelectric type (such as light shield), magnetic sensitive type (such as Hall sensor), among which Hall sensor is the most widely used.

2.sensorless control

The brushless DC motor control method without position sensor does not directly install position sensor on the stator of brushless DC motor to detect rotor position. It generally uses direct back EMF detection, back EMF third harmonic method, current path monitoring method, open-circuit phase voltage detection method, phase inductance method, back EMF logic level integral comparison method to indirectly detect the rotor position.

3. intelligent control

Intelligent control is the development stage of control theory, generally including fuzzy control, neural network control, expert system and so on. Intelligent control system has the functions of self-learning, self-adapting and self-organizing. It can solve model uncertainty, nonlinear control and other complex problems. Strictly speaking, BLDCM is a multi-variable, nonlinear, strong coupling object, so the use of intelligent control can achieve satisfactory control results. At present, many mature intelligent control methods have been applied to brushless DC motor control, such as fuzzy-PID control combined with fuzzy control and PID control, fuzzy control combined with neural network control, fuzzy control optimized by genetic algorithm for membership parameters, single neuron adaptive control and so on.

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