Correction method and circuit of AC load power factor

Abstract

The invention discloses a correction method and a circuit of an AC load power factor. The correction method adopts a capacitance integral method to respectively improve capacitor charge-discharge frequency in the AC positive and negative half period so as to improve the using powder of the capacitor and correct the AC load power factor; in the charge-discharge process, the capacitor adopts 5-100 kilocycles PWM pulse width modulation to adjust the charge-discharge current to the charge-discharge capacitor by a power switch element; electric energy in the discharge process of the charge-discharge capacitor is released to an absorption capacitor and is fed back to the AC power supply by the integral of a capacitance-type bootstrap circuit formed by connecting absorption capacitance with coupling capacitance in series to realize the automatic correction of the AC load power factor. The correction circuit adopts the correction method of the invention and mainly comprises an AC main correction circuit, an AC / DC three-path DC voltage-stabilized power supply, a detection circuit and a control circuit. The invention can directly correct the AC load power factor.

Description

technical field [0001] The invention belongs to electronic circuit technology, and relates to a method and circuit for correcting AC load power factor, which is applied to improve the power factor of electric equipment. Background technique [0002] The power factor compensation of alternating current mostly adopts the step-by-step switching power capacitor method. In the step-by-step switching process, it is impossible for the capacitor to perform accurate dynamic compensation for the power factor of the load, which will cause over-compensation and under-compensation. Among them, over-compensation will cause the voltage to be too high, and in severe cases, the electrical appliances will be burned; while under-compensation, the compensation equipment cannot play its due role. On the other hand, because the corresponding capacitor value cannot be input according to the load size, the existing power factor compensation equipment has large volume, high loss, strong noise, high...

AI Technical Summary

Problems solved by technology

The power factor correction device has the characteristics of small size, low loss and high efficiency, but the existing power factor correction methods and circuits have major defects: that is, currently technically only the power factor correction can be performed on the DC load after AC rectification, but not Using the advantages of the correction method to perform power factor correction on AC loads, the scope of use is limited

Within the scope of the applicant's search, no relevant literature reports have been found on the method of power factor correction for AC loads and the method of using capacitors to form a bootstrap circuit for AC load correction circuits to feed back electric energy

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