Fan and its speed control method

Abstract

A method for controlling a rotational speed of a fan ( F ) includes using a control unit (1) to start a motor (2) according to an initial duty cycle value ( D ). In a first constant speed step ( S1 ), the duty cycle value ( D ) is changed to make a motor rotational speed ( R ) equal to a first target rotational speed ( R1 ). When the duty cycle value ( D ) and a first target duty cycle value ( D1 ) satisfy a first relational expression, the motor rotational speed ( R ) is compared with a second target rotational speed ( R2 ), and the duty cycle value ( D ) is changed to make the motor rotational speed ( R ) equal to the second target rotational speed ( R2 ). When the duty cycle value ( D ) and a second target duty cycle value ( D2 ) satisfy a second relational expression, the first constant speed step ( S1 ) is performed. A fan ( F ) is also disclosed.

Description

technical field [0001] The present invention relates to a fan and its speed control method, in particular to a fan capable of automatically adjusting the speed without referring to the operating current value of the motor and its speed control method. Background technique [0002] Existing ventilation fans, or ventilators, can be connected to multiple spaces or machines by multiple air ducts, and a motor drives the fan to rotate to push air flow for ventilation or exhaust. Factors such as the size and quantity of the space to be exhausted, the length of the air duct, and the width of the diameter will all affect the static pressure on the fan. When the power driven by the motor to rotate the fan is fixed, the increase in the static pressure will reduce the air volume of the fan, and vice versa. , the decrease in static pressure increases the air volume of the fan. When the air volume of the fan is less than the required total exhaust volume, it will cause low exhaust gas emi...

AI Technical Summary

Problems solved by technology

[0003] However, to read the current value, the ammeter must be connected in series with the circuit under test. Therefore, the motor line needs to be cut off before installing or replacing the ammeter, which makes it difficult to use and maintain, and the current signal needs to be enhanced by an amplifier, which is prone to noise. Additional components such as filters need to be connected to remove noise, so the circuit is complex, increasing the cost of circuit setup, and the accuracy of calculation results affects the stability of the speed

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