Discontinuous mode PFC converter with low-input current harmonic waves

Abstract

The present invention relates to a discontinuous mode PFC converter with low-input current harmonic waves. The converter comprises a main power circuit and a control circuit, an input of a rectifier bridge in the main power circuit is an AC voltage source, an output of the rectifier bridge in the main power circuit is taken as an input of a Boost circuit, a resonance suppression circuit is connected in series between a boost inductor and a switch tube in the Boost circuit, and a load is connected in parallel with an output capacitor of the Boost circuit; and input / output voltage signals are obtained through sampling in the Boost circuit, respectively pass through an input voltage feedforward module and a voltage ring module in the control circuit and are output to a duty ratio generation module to obtain duty ratio signals required by the switch tube of the Boost circuit. The influence of parasitic parameters of the discontinuous mode PFC converter is overcome, the input current harmonic waves are reduced, the efficiency of the converter is improved, the requirements for parasitic parameters of the switch tube and a freewheeling diode are reduced, and the cost of a device is saved.

Description

technical field [0001] The invention relates to the field of power electronic converters, in particular to a discontinuous mode PFC converter with low input current harmonics. Background technique [0002] The performance of the power factor correction (PFC) circuit is closely related to the topology, control method and working mode of the circuit. How to reduce the input current harmonic is an important indicator of PFC design. Among many power electronic topologies, Boost converters are widely used as PFC circuits because of their simple topology, high conversion efficiency, and easy implementation of control strategies. [0003] According to whether the inductor current is continuous, the boost converter can be divided into three types: continuous conduction mode (CCM), critical continuous conduction mode (CRM) and discontinuous conduction mode (DCM). The inductor current of the Boost PFC converter designed according to DCM will work in the discontinuous mode in the ful...

AI Technical Summary

Problems solved by technology

Usually, when analyzing the Boost converter, all components are considered to be ideal; however, in the actual circuit, due to the influence of the non-ideal characteristics of the Boost circuit, the inductor current in the third modal stage of the discontinuous mode, the inductance in the circuit and the The parasitic capacitance on the switching tube and the freewheeling diode resonates, generating a resonant current, resulting in an increase in the harmonic content of the input current

When the parasitic parameters of the circuit are large, the input current distortion is serious, and the total harmonic distortion (THD) is very high

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