Single-phase three-level bridgeless PFC (power factor correction) rectifier

Abstract

The invention relates to a single-phase three-level bridgeless PFC (power factor correction) rectifier, comprising a crossbar filter network, a power electronic switch network, direct-current capacitor C1 and direct-current capacitor C2; a first input end of the crossbar filter network is connected with a first end of power supply voltage vs, a second input end of the crossbar filter network is connected with a second end of the power supply voltage vs, a first output end of the crossbar filter network is connected with a first input end of the power electronic switch network, and a second output end of the crossbar filter network is connected with a second input end of the power electronic switch network. Since the crossbar filter network is introduced to an existing three-level bridgeless PFC filter, the advantages of the original three-level bridgeless PFC filter can be retained, and common mode current of the rectifier can be greatly decreased at the premise of not increasing leakcurrent and safety risk; the single-phase three-level bridgeless PFC rectifier is suitable for use in places having strict limitations on leak current and common mode noise.

Description

technical field [0001] The invention belongs to the technical field of high-efficiency and high-power-density PFC rectifiers, and in particular relates to a single-phase three-level bridgeless PFC rectifier. Background technique [0002] The input stage of the switching power supply usually adopts an uncontrollable capacitive rectification circuit composed of diodes. The main disadvantage of this circuit is that the input current contains a large number of low-order harmonic components, and the power factor is very low, which causes serious pollution to the power grid. Active PFC technology composed of fully controlled power electronic switching devices can effectively reduce harmonic content and improve power factor. Due to the high-frequency switch control, the volume of passive filter components in the active PFC circuit, such as inductors and capacitors, can be greatly reduced, which is very beneficial for improving the power density of the converter. At present, the ap...

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Problems solved by technology

This circuit is easy to implement and has high reliability, but there are several problems: 1) the high-frequency switching ripple of the inductor current is large; 2) the voltage stress of the switching device is large; 3) when the input voltage is low, the on-state loss of the diode rectifier bridge Big

Foreign scholars have proposed a single-phase three-level bridgeless PFC circuit, which can realize the uniform charging and discharging of two DC capacitors in half a power cycle, thus reducing the capacitance and volume of the capacitor, but the common mode noise is large, which is not easy Facilitate EMI filter design

The method of installing a common-mode filter capacitor (Y capacitor) between the main circuit of the rectifier and the case can effectively reduce the common-mode noise of the rectifier, but it will increase leakage current and safety risks

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