Control pulse generating circuit and regulating system and method of direct current brushless motor speed

Abstract

The invention discloses a control pulse generating circuit used for regulating the direct current brushless motor speed, comprising a temperature signal processing unit, a PWM signal processing unit, a triangular wave generating unit and a control pulse output unit, wherein the temperature signal processing unit converts the detected ambient temperature signal into the current signal in approximately linear relationship with the ambient temperature; the PWM signal processing unit receives the PWM input signal and the current signal and converts the PWM signal into the direct current voltage signal related to the duty ratio of the PWM input signal and the ambient temperature; the triangular wave generating unit generates a triangular wave signal; and the control pulse output unit compares the direct current voltage signal with the triangular wave signal and generates a control pulse signal with duty ratio related to the duty ratio of the PWM input signal and the ambient temperature signal. The invention also discloses a regulating system and method of direct current brushless motor speed. The embodiment of the invention can realize simultaneously utilizing the ambient temperature and the PWM signal to regulate the speed of the direct current brushless motor.

Description

technical field [0001] The invention relates to the technical field of motor control, in particular to a control pulse generating circuit and a system and method for adjusting the rotational speed of a DC brushless motor. Background technique [0002] The adjustable-speed single-phase DC brushless motor has the advantages of energy saving and low noise, and has been widely researched and applied in technical fields such as cooling fans. [0003] In the prior art, the speed regulation of the DC brushless motor can be divided into the following two types. [0004] One is to use temperature-sensitive devices, specifically: convert the temperature signal into a voltage signal, and compare it with the triangular wave to output a square wave with a different width to realize the speed regulation of the brushless DC motor and then control the operation of the cooling fan. When the temperature is high, the duty cycle of the output square wave is large, the speed of the motor is hig...

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Problems solved by technology

[0011] However, in the two speed regulation methods of the prior art, either only the temperature sensitive resistor can be used to adjust the motor speed, or the PWM signal can only be used to adjust the motor speed, and the temperature sensitive resistor and the PWM signal cannot be used to realize the motor speed regulation at the same time. dissatisfied with figure 1 The speed regulation function shown requires the cooling fan demand

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