Single-phase rectifier with apfc circuit and its AC input voltage amplitude detection method

Abstract

Aimed at the defects in the alternating-current input voltage detection of the single-phase rectifier with the APFC circuit in the prior art, the invention provides a single-phase rectifier with an APFC circuit and an alternating-current input voltage amplitude detection method for the single-phase rectifier. By arranging a voltage dividing and sampling circuit at the output end of the single-phase rectifier, the invention provides a low-cost single-phase rectifier with the APFC circuit, the single-phase rectifier can carry out low-cost alternating-current input voltage amplitude detection the under the premise that additional circuits are added as few as possible, the circuit structure is simple and reliable, the single-phase rectifier can be conveniently applied to different power factor correction power grades by arranging an auxiliary rectification circuit, and under the heavy-load condition, the voltage drop of the diodes of the single-phase rectification circuit can be prevented from affecting the precision of alternating-current input voltage amplitude detection.

Description

technical field [0001] The invention relates to the technical field of active power factor correction, in particular to a single-phase rectifier with an APFC circuit and a method for detecting the amplitude of an AC input voltage. Background technique [0002] After the AC input power is rectified and filtered, the non-linear load distorts the input current waveform, and the input current is a pulse waveform, which contains a large number of harmonic components, making the power factor very low. The resulting problems are: Harmonic current pollutes the power grid and interferes with other electrical equipment; under the condition of a certain input power, the input current is large, and the amount of input circuit breakers and power lines must be increased; the three-phase four-wire system When the power is supplied, the current in the neutral line is relatively large. Since there is no overcurrent protection device in the neutral line, it may overheat or even catch fire. F...

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Problems solved by technology

The resulting problems are: Harmonic current pollutes the power grid and interferes with other electrical equipment; under the condition of a certain input power, the input current is large, and the amount of input circuit breakers and power lines must be increased; the three-phase four-wire system When the power is supplied, the current in the neutral line is relatively large. Since there is no overcurrent protection device in the neutral line, it may overheat or even catch fire.

[0004] For a single-phase rectifier equipped with an APFC circuit, in the process of active power factor correction, it is necessary to detect the input single-phase alternating current. The more conventional method is to use a voltage transformer or a circuit composed of an analog chip for detection. The circuit structure of the above method is complicated, the volume is large, and the circuit cost is relatively high.

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