Flyback power factor correction (PFC) converter with bridge-free structure

Abstract

The invention provides a flyback power factor correction (PFC) converter without a bridge-free structure. The flyback PFC converter comprises an isolation transformer, a bidirectional switch, a secondary-side diode bridge rectifier circuit, an output capacitor and a load. The bidirectional switch is composed of two switch tubes which are connected in series. The two switch tubes share the same source electrode and the same gate electrode. One end of a voltage source in a main power circuit is connected with any end of the primary side of the isolation transformer. The other end of the primary side of the isolation transformer is connected with any end of the bidirectional switch. The other end of the bidirectional switch is connected with the other end of the voltage source. The secondary side of the isolation transformer is connected with the diode rectifier circuit. The diode rectifier circuit is connected with an energy storage capacitor and the load in parallel. According to the technical scheme of the invention, the flyback PFC converter eliminates the defect of current zero-zero distortion and reduces the conduction loss at the same time. On the premise that the power factor is not changed, the overall efficiency is improved.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a power factor correction technology with low input current harmonics, low voltage output and high efficiency, and in particular to a flyback power factor correction PFC converter with a bridgeless structure. Background technique [0002] In recent years, power electronics technology has developed rapidly, and power supply technology, which is an important part of the power electronics field, has gradually become a hot spot in application and research. Switching power supply has established its mainstream position in the field of power supply due to its high efficiency and high power density, but when connected to different loads, the input current will be distorted, reactive power will be generated, and a large amount of current high-order harmonics will pollute the power grid . There are two main ways to improve the power factor of the power grid. The traditional way...

AI Technical Summary

Problems solved by technology

[0003] Power factor correction PFC belongs to AC-DC conversion. Traditionally, there is a rectifier bridge on the primary side of the isolation transformer, and the diode in the rectifier bridge has a conduction voltage drop. As a result, the current change cannot follow the voltage change when the current crosses zero, resulting in a current zero crossing. Distortion, in order to eliminate the current zero-crossing distortion, it is necessary to add a feedforward link to the control circuit, which great...

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