A circuit control method and device

Abstract

The invention discloses a circuit control method and equipment. The method includes: calculating that the circuit is in the discontinuous mode by equating the average current in one switching cycle when the step-up power factor correction circuit is in the discontinuous mode to an ideal input current When the duty cycle is used; the duty cycle is used as the first feed-forward wave; when the circuit is in discontinuous mode and the actual load is not greater than the set load threshold, the value at the point where the voltage crosses zero is selected to be much smaller than the second feed-forward The first feed-forward wave of the feed wave is used as the feed-forward wave of the circuit, and the circuit is fed-forward controlled according to the selected feed-forward wave, wherein the second feed-forward wave is 1-Uin / UBus, so that when the boost power factor correction circuit is in discontinuous mode and the load is small, the feed-forward wave of the circuit will be much smaller than 1 at the voltage zero crossing, that is, there is no full duty cycle, so the bus voltage will not be arched High, and can also achieve the effects of improving the sinusoidal nature of the current, reducing the harmonic content of the input current, and improving the PF.

Description

technical field [0001] The invention relates to the technical field of circuit control, in particular to a circuit control method and equipment. Background technique [0002] When the BOOST PFC (boost power factor correction) circuit load is less than the set load threshold (such as small load or no load) and the inductor current works in discontinuous mode, if the traditional double-loop control + feedforward is still used to control the circuit accordingly Control, there will be a problem that the bus voltage soars when the voltage crosses zero. [0003] This is because the traditional double-loop control + feedforward uses the traditional feedforward wave 1-U suitable for continuous mode in / U Bus , where U in is the input voltage of the circuit, U Bus As a result, when the inductor current works in discontinuous mode, a large duty cycle will be generated at the point where the voltage crosses zero, so that the circuit will always charge the bus capacitor. If so When...

AI Technical Summary

Problems solved by technology

[0006] The embodiment of the present invention provides a circuit control method and equipment to solve the current problem that when the BOOST PFC circuit works in discontinuous mode and the load is less than the set load threshold, the traditional double-loop control + feedforward is used to control the circuit accordingly Problems that lead to poor circuit performance such as bus voltage spikes at voltage zero crossings

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