Control method for brushless DC motor

Abstract

The invention provides a control method of a DC brushless machine, comprising a voltage waveform sampling circuit, an inverter and a microcontroller, wherein the method comprises: detecting the back electromotive force voltage waveform of the DC brushless machine in certain given rotating speed, storing the voltage waveform data in the microcontroller, building and storing the proportional relation data of the rotating speed and the back electromotive force by the microcontroller; after outputting the voltage from the inverter to the DC brushless machine, sampling the rotating speed in the DC brushless machine by the voltage waveform sampling circuit and the voltage waveform data outputted by the inverter, and transmitting to the microcontroller; computing the corresponding back electromotive force voltage waveform of the DC brushless machine and the error threshold range in the current rotating speed by the microcontroller, and judging whether the voltage waveform data input by the inverter exceeds the error threshold range, if true, the microcontroller emits the control signal to the inverter. The DC brushless machine of the invention has small vibration and advanced efficiency.

Description

technical field [0001] The invention relates to a control method of a motor, in particular to a control method of a DC brushless motor. Background technique [0002] Brushless DC motor is a kind of DC motor that cancels mechanical contact parts such as brushes and commutators. It uses microcontrollers instead of brushes and commutators. Therefore, the speed of brushless DC motors can be designed to be higher. , and can effectively avoid the noise generated by the brushes and commutator. [0003] The existing DC brushless motor adopts a 180° control method, and its control circuit includes a microcontroller and an inverter. The microcontroller outputs a control signal to the inverter, and the inverter sends a DC brushless Each phase of the brush motor provides a sine wave voltage to drive the brushless DC motor to work. [0004] Since the brushless DC motor generates back electromotive force during operation, when the voltage waveform provided by the inverter to the brushle...

AI Technical Summary

Problems solved by technology

[0004] Since the brushless DC motor generates back electromotive force during operation, when the voltage waveform provided by the inverter to the brushless DC motor is inconsistent with the voltage waveform of the opposite electromotive force, for example, there is a large phase between the voltage waveform provided by the inverter and the back electromotive voltage waveform Poor, or the waveform cycle is inconsistent, or there is a large difference in amplitude, which will make the torque generated by the part of the energized current in the brushless DC motor be opposite to the direction of the motor rotation, thus causing the brushless DC motor to vibrate and generate noise

However, the existing control of brushless DC motors does not consider whether the voltage waveform provided by the inverter to the brushless DC motor matches the voltage waveform of the back electromotive force, and often cannot effectively avoid the vibration of the brushless DC motor. At the same time, it cannot improve the DC Efficiency of brushless motors

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