Control Method Of Brushless DC Motor

Brushless DC motor control is divided into three types: with position sensor, without position sensor and intelligent control.

1. Position sensor control

The position sensor control is to install a position sensor on the stator of the brushless DC motor to detect the rotor position and control the commutation of the stator winding. The position sensors used include electromagnetic type (such as reluctance resolver), photoelectric type (such as shading plate), magnetic sensitive type (such as Hall sensor), etc. Among them, Hall sensor is widely used.

2. No position sensor control

The position sensorless DC brushless motor control method does not directly install a position sensor on the stator of the brushless DC motor to detect the rotor position. Generally, methods such as direct back EMF detection, back EMF third harmonic method, current path monitoring method, open-circuit phase voltage detection method, phase inductance method, and back EMF logic level integral comparison method are used to indirectly detect the position of the rotor.

3. Intelligent control

Intelligent control is the development stage of control theory, generally including fuzzy control, neural network control, expert system and so on. The intelligent control system has functions such as self-learning, self-adaptation, and self-organization, and can solve more complex problems such as model uncertainty and nonlinear control. Strictly speaking, BLDCM is a multi-variable, nonlinear, and strongly coupled object, so using intelligent control can achieve a relatively satisfactory control effect. At present, many mature intelligent control methods have been applied to the control of brushless DC motors, such as: Fuzzy-PID control combining fuzzy control and PID control, compound control combining fuzzy control and neural network, subordinate parameter inheritance algorithm optimization fuzzy control , Single neuron adaptive control, etc.