Control method and device for switch tube of PFC circuit

Abstract

The invention discloses a control method for switch tube of a PFC circuit. The control method comprises the steps of obtaining an input current, an input voltage and a busbar voltage of the PFC circuit based on each control cycle of the switch tube; obtaining output quantity of a voltage loop based on a deviation control on the voltage loop based on a difference value between a set value of the busbar voltage and the practical value of the busbar voltage; determining a reference value of an electric current loop in the current cycle based on output quantity of the voltage and a reference value changing threshold value of the electric current loop; obtaining output quantity of an electric current loop by conducting deviation control on the electric current loop based on the differential value of the reference value of the electric current loop and the value of the input electric current; adding the output quantity of the electric current loop with a feedforward quantity to obtain a duty ratio signal which can control conduction and blockage of a switch tube of the PFC circuit. The control method for the switch tube of the PFC circuit can effectively eliminate phenomena of overcurrent or overvoltage and undervoltage of the generatrix caused due to voltage flicker in the PFC circuit and guarantee stability of the PFC device, therefore the method is safe and effective.

Description

technical field [0001] The invention relates to the field of control, in particular to a method and device for controlling a switching tube of a PFC circuit. Background technique [0002] The PFC circuit, that is, the power factor correction circuit, is mainly used to deal with the current distortion problem during the AC to DC conversion process of the power supply. There are two main types of PFC circuits, one is an active PFC circuit and the other is a passive PFC circuit. Active PFC is equivalent to a switching power supply. The control chip controls the on and off of the switch tube to make the input current waveform a sine wave similar to the input voltage waveform and in the same phase, so the power factor is improved. [0003] Such as figure 1 As a typical PFC circuit, this circuit uses a boost boost topology. This PFC circuit uses a rectifier circuit to carry out bridge rectification on the AC voltage to provide the voltage Vac to the inductor, and controls the o...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the embodiments of the present invention is to provide a switch tube control method and device for a PFC circuit, which can effectively solve the problem of frequent restarts of the PFC device caused by voltage flicker

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