Method and system for judging clockwise and counterclockwise wind of fan

Abstract

The method comprises the following steps: respectively conducting lower bridge power switches of an A phase, a B phase and a C phase, acquiring voltage differences of the A phase, the B phase and the C phase by collecting drain electrodes and source electrodes of the power switches, and obtaining a current; obtaining a motor rotor angle theta1 and a current peak value K according to the current magnitude; obtaining a motor power generation constant and a back electromotive force constant, and calculating to obtain an estimated angular frequency w1 according to the motor power generation constant and the back electromotive force constant; determining the sampling interval time of turning on the A-phase, B-phase and C-phase lower bridge power switches again through the pre-estimated angular frequency w1; when the sampling interval time is up, switching on the A-phase lower bridge power switch, the B-phase lower bridge power switch and the C-phase lower bridge power switch again, obtaining the voltage difference of the A-phase lower bridge power switch, the B-phase lower bridge power switch and the C-phase lower bridge power switch, obtaining the current angle theta2 through calculation, and obtaining the forward and reverse wind direction according to the relation between the theta1, the theta2 and the sampling time accurate estimation angular frequency w and the theta1 and the theta2. The method avoids an external circuit, reduces hardware cost, and simplifies a motor control circuit.

Description

technical field [0001] The invention belongs to the technical field of air-conditioning fans, and in particular relates to a method for judging whether the fan is in the wind or against the wind. Background technique [0002] With the development of science and technology and the progress of society, people's demand for materials is getting higher and higher, and the popularity of air conditioners in the domestic market is also increasing. People's demand for air conditioners in summer and winter is increasing. The starting stability of the fan in the air conditioner external unit has always been one of the core technologies that air conditioner manufacturers want to overcome, and it is also an important standard for measuring the quality of the air conditioner external unit. [0003] The external unit of ordinary air conditioners is suspended outdoors, and the fan inside the external unit will not remain static due to the influence of natural wind. If the fan rotates under ...

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Problems solved by technology

[0006] The invention provides a method for judging the forward and reverse wind of a fan. The rotational speed and angular velocity are obtained by detecting the current, and the positive and negative angular velocity is used to obtain the forward and reverse wind state of the fan, and then switch to the closed-loop starting program to solve the problem of the smooth start of the air conditioner fan under the influence of natural wind. The problem

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