A low-power ventilation fan

Abstract

The invention discloses a low-power ventilator. A control circuit drives a switch according to the terminal voltage of a stator winding when the power voltage and power current are zero, so that the current input to a motor winding by a power source is controlled. According to the low-power ventilator, (a) a rotor is made to be located in the position where an acute angle is formed between the rotor and the axis of a magnetic field formed when current in a certain direction is introduced into a permanent magnet axis lead stator winding; (b) a first current pulse which starts from a first time delay of a zero crossing point of the power voltage and is in the direction opposite to the direction in the current (a) is input into the winding; and (c) when the absolute value of the characteristic value of the terminal voltage is larger than a stipulated value and the time difference between a first zero crossing point and a third zero crossing point of the power voltage is smaller than a stipulated value, a second current pulse which is in the direction opposite to the direction of the first current pulse is input the winding, and a time delay exists between the second current pulse and the third zero crossing point of the power voltage, the steps from (a) to (c) are executed again otherwise, the first time delay is prolonged when the absolute value is larger than the stipulated value and the first zero crossing point advances the third zero crossing point of the alternate power voltage, and the first time delay is shortened otherwise. By the adoption of the design, use of an independent rotor position detecting element can be avoided.

Description

technical field [0001] The invention relates to a low-power ventilating fan directly driven by a miniature permanent magnet synchronous motor, in particular to the cooperation of its mechanical structure, electromagnetic structure and control method; in the international patent classification table, the classification belongs to F04D 25 / 08. Background technique [0002] Ventilation fans are widely used and run for a long time, so there is an urgent need for low-cost manufacturing and energy-saving operation. Aiming at the fact that the ventilating fan is currently driven by an asynchronous motor and the efficiency is relatively low, the low-power ventilating fan proposed in the prior application CN201110303632.1 which has been authorized by the applicant is directly driven by a permanent magnet synchronous motor, which is energy-saving and has a small volume, and is It has better starting and running performance in the direction of rotation and lower cost, but the motor need...

AI Technical Summary

Problems solved by technology

Aiming at the fact that the ventilation fan is currently driven by an asynchronous motor and the efficiency is relatively low, the low-power ventilation fan proposed by the applicant in the prior application CN201110303632.1 which has been authorized by the applicant is directly driven by a permanent magnet synchronous motor, which is energy-saving and has a small volume, and is available in a predetermined It has better starting and running performance in the direction of rotation, and the cost is lower, but the motor needs to be equipped with a separate rotor position detection element

Images