AC/DC converter

Abstract

The invention discloses an AC / DC converter which carries out rectification and filtration to input alternating voltage by ensuing that the needed working voltage of a load is lower than presetting value; the alternating voltage power factor after the rectification and filtration are corrected forms power factor correction PFC busbar voltage, and the PFC busbar voltage is adjusted at the same time; in addition, in an AC / DC converting circuit, duty ratio of a complementary metal oxide semiconductor MOS switching tube which carries out DC / DC conversion to a PFC bus is adjusted, and the rectification and filtration are carried out to the voltage output by the DC / DC converting circuit, and the voltage is output to the load. By applying the AC / DC converter and properly reducing the PFC busbar voltage output by a PFC circuit, the MOS switching tube in the DC / DC converting circuit can work in a duty ratio with higher working efficiency when the working voltage of the load is lower, thus ensuring the direct current working voltage needed by the load, improving the efficiency when the AC / DC converter outputs low voltage and reducing loss.

Description

technical field [0001] The present invention relates to alternating current / direct current (AC / DC, Alternating Current / Direct Current) voltage conversion technology, in particular to an AC / DC converter. Background technique [0002] The AC / DC voltage conversion circuit is a circuit that converts AC voltage into DC voltage, and is widely used in DC regulated power supplies, DC motors, industrial welding, and communications. Through filter rectification, voltage stabilization, voltage conversion, output filter rectification and voltage stabilization of AC voltage, stable DC voltage is output to meet the needs of various DC stabilized voltages in production and life. [0003] figure 1 It is a structural schematic diagram of an existing AC / DC converter, see figure 1 , the AC / DC converter includes: an input voltage electromagnetic interference (EMI, Electro Magnetic Interference) filter circuit, a power factor correction (PFC, Power Factor Correct) circuit, a DC / DC conversion c...

AI Technical Summary

Problems solved by technology

[0041] For the conversion circuit with a resonant inductance connected in series on the primary side, the resonant inductance connected in series will lengthen the time for the current reversal. During the current reversal process, The two rectifier diodes on the secondary side of the converter are both in the conduction state, causing the secondary side voltage to be zero, which reduces the duty cycle range of the conversion circuit, so that the DC voltage output by the conversion circuit cannot meet the needs of different loads. At the same time, At a small duty cycle, the converter efficiency drops

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