Small-power ventilator directly driven by permanent-magnet synchronous electromotor

Abstract

The invention provides a small-power ventilator directly driven by a permanent-magnet synchronous electromotor. The small-power ventilator comprises an impeller and the electromotor directly driving the impeller, wherein the impeller performs directional rotation and is formed through injection moulding, a stator winding of the electromotor is connected with an alternating-current power source according to the stipulated winding direction, a rotor is a permanent magnet rotor and is of the same number of poles as that of a stator, and in a free state, the axes of all poles of the rotor are deviated by an acute angle in the predetermined rotation direction with the axis of the closest pole of the stator being the reference. The alternating-current power source supplies power to the stator winding through a switch controlled by a control circuit. When the number of poles of the stator is four, the diameter of the impeller is smaller than or equal to 100 mm, or when the number of poles of the stator is six, the diameter of the impeller is smaller than or equal to 130 mm, or when the number of poles of the stator is eight, the diameter of the impeller is smaller than or equal to 150 mm; a built-in program of the control circuit comprises the step that the switch is driven according to the detected signal so as to control the alternating-current power source to supply power to the stator winding; and before the ventilator is started, one pole face of a stator iron core represents magnetism of the stipulated polarity. By means of the design, the prepositioning detection process performed when a ventilator of the traditional technology is started is omitted, performance is improved, and the cost is lowered.

Description

Technical field [0001] The invention relates to a low-power ventilating fan directly driven by a permanent magnet synchronous motor, in particular to the coordination of its mechanical structure, electromagnetic structure and control method; IPC classification belongs to F04D25 / 08. Background technique [0002] Ventilation fans are widely used and have a long operating time, and there is an urgent need for low-cost manufacturing and energy-saving operation. In view of the fact that the ventilation fan is driven by an asynchronous motor and the efficiency is low, the applicant's previous application CN201510395121.5 proposed a low-power ventilation fan directly driven by a permanent magnet synchronous motor, which saves energy and is small in size, and has a relatively high degree of rotation in a predetermined direction of rotation. Good starting and running performance, and no separate rotor position detection element is required, but in order to start and run according to the p...

AI Technical Summary

Problems solved by technology

In view of the fact that the ventilation fan is driven by an asynchronous motor and the efficiency is relatively low, the low-power ventilation fan proposed by the applicant in the prior application CN201510395121.5 is directly driven by a permanent magnet synchronous motor, which is energy-saving and has a small volume, and has a relatively high speed in the predetermined direction of rotation. It has good starting and running performance, and there is no need to set a separate rotor position detection element, but in order to make it start and run according to the predetermined direction, it needs to control its power supply. The first step is pre-positioning-determining the magnetic pole of the permanent magnet rotor relative to the magnetic pole of the stator. position, and then according to the detection result and the predetermined direction, the voltage of the corresponding polarity waveform is applied to the stator, and the detection circuit and program are more complicated

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