Method for controlling brushless direct current motor

Abstract

The invention provides a method for controlling a brushless direct current motor. The method comprises the following steps that S1, the open loop of the brushless direct current motor is controlled to be started; S2, after the brushless direct current motor is started, the comparison signal of the three-phase end voltage and the neutral point voltage of the brushless direct current motor is detected; S3, the zero crossing point signal of the brushless direct current motor is judged according to the comparison signal of the three-phase end voltage and the neutral point voltage; S4, the position and the rotating speed of the rotor of the brushless direct current motor are obtained according to the zero crossing point signal of the brushless direct current motor; S5, the brushless direct current motor is controlled according to the position and the rotating speed of the rotor of the brushless direct current motor. According to the method for controlling the brushless direct current motor, position detection does not need to be carried out through a position sensor, the size and weight of the brushless direct current motor can be reduced, the development cost of the motor can be lowered, the motor can be controlled to be operated at high speed, and the reliability of motor operation can be improved.

Description

technical field [0001] The invention relates to the technical field of motor control, in particular to a control method for a brushless DC motor. Background technique [0002] Brushless DC motor is a kind of DC motor developed with the development of microprocessor technology, the continuous application of high frequency and low power consumption power devices, and the continuous improvement of motor drive control methods. Its electromagnetic structure is the same as that of brushed DC motor. , but the winding of the brushless DC motor is installed on the stator, and the magnet is installed on the rotor. With the continuous development of drive control technology and electronic technology, brushless DC motors have been widely used. [0003] In the closed-loop control of the brushless DC motor, it is necessary to detect the rotor position of the motor. In the prior art, the detection of the position of the motor rotor can include two methods: through the position sensor and...

AI Technical Summary

Problems solved by technology

[0004] However, there are many shortcomings in the method of detecting the rotor position of the motor by the position sensor: for example: 1. The cost of the motor increases, such as the cost of position sensors such as Hall sensors, rotary transformers and photoelectric encoder discs. large, thus increasing the cost of the motor

2. The size of the motor is large, which is not conducive to miniaturization design

3. The reliability is poor. The position sensor adds multiple signal lines, which is susceptible to interference and reduces the reliability of the system. In addition, in harsh environments such as high temperature, high pressure and humidity, the failure rate of the position sensor is relatively high.

4. The installation accuracy is high, and the production process of the motor is high

In view of the above shortcomings of detecting the rotor position of the motor through the position sensor, in the field of motor control, the control method that does not pass the detection of the position sensor is being continuously researched and explored, and it is also applied in some occasions. However, the control method that does not pass the detection of the position sensor In the method, the operating speed of the motor is low, the speed ratio is small, and when the motor speed is high or the load fluctuates greatly, the motor is prone to operating failures, so the reliability of the motor is poor, especially in the field of national defense. The reliability of product operation is Critical

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