Frequency conversion smoke exhaust ventilator

Abstract

The invention discloses a frequency conversion smoke exhaust ventilator. The frequency conversion smoke exhaust ventilator comprises a main control circuit board and a frequency conversion circuit board; the frequency conversion smoke exhaust ventilator also comprises a low-voltage power supply circuit for supplying power for the main control circuit board and the frequency conversion circuit board; the low-voltage power supply circuit comprises a bridge type rectifying circuit, a single chip microcomputer, a capacitive program-controlled voltage-reduction circuit and a switch circuit; the bridge type rectifying circuit comprises triodes Q1 and Q3 and diodes D2 and D3; the capacitive program-controlled voltage-reduction circuit comprises capacitors C2, C3 and C4 and triodes Q4 and Q5; the switch circuit comprises two groups of program-controlled synchronous switches; the first group switches are connected with the output end of the bridge type rectifying circuit; the second group switches are connected with the output ends of the capacitor C2 and the triode Q4; and the two groups of the program-controlled synchronous switches are closed in different time. The frequency conversion smoke exhaust ventilator adopts the bridge type switch structure, so that the purpose of outputting the safe and isolated power supply is realized.

Description

technical field [0001] The invention relates to the technical field of range hoods, and more specifically relates to a range hood with frequency conversion. Background technique [0002] At present, the motors used in the range hoods commonly used by people are generally single-phase motors, and their operating frequency does not change. The control of its speed is realized by changing the voltage by adjusting the turns ratio of the inner coil of the motor. Therefore, there are not many gears for its speed, and it cannot be adjusted steplessly. In view of this, some manufacturers have proposed the scheme of frequency conversion hood. In the way of PWM modulation, output variable frequency alternating current. By changing the frequency of the input current of the asynchronous motor, the speed of the single-phase asynchronous motor is changed. For example, a Chinese utility model patent frequency conversion range hood disclosed on February 28, 2007, by adding a frequency co...

AI Technical Summary

Problems solved by technology

The transformer is an inductive reactance component, and the inductive circuit will increase the reactive power of the mains power and reduce the power factor. Therefore, the use of inductive reactance appliances will cause huge energy waste to the country's mains power supply.

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