PFC frequency conversion control method and device and controller

Abstract

The invention relates to a PFC frequency conversion control method and device and a controller. The PFC frequency conversion control method comprises the steps of: acquiring the input voltage of a PFC circuit, the output voltage of the PFC circuit, and the inductive current flowing through an inductor in the PFC circuit; obtaining switching frequency signals required by the PFC circuit at different moments in each power frequency period according to the input voltage, the output voltage and the inductive current, the switching frequency signals at two adjacent moments being different in size; and further generating a driving signal according to the switching frequency signal required at each moment and a duty ratio modulation signal, the driving signal being used for driving on-off of a switching tube in the PFC circuit. According to the embodiment provided by the invention, different switching frequencies are adopted at different moments in one power frequency period to generate the driving signal finally loaded on the switching tube in the PFC circuit, so that the switching frequencies at other moments except when the input current fundamental waveform is at the peak value are greatly reduced, the loss of the switching tube is reduced, and the efficiency of the PFC circuit is improved.

Description

technical field [0001] The invention relates to the technical field of switching power supplies, in particular to a PFC frequency conversion control method, device and controller. Background technique [0002] The statements herein merely provide background information related to the present application and do not necessarily constitute prior art. [0003] Switching power supplies are essential and critical components in modern electronic systems. With the continuous advancement of science and technology, people have higher and higher requirements for switching power supplies, and are increasingly pursuing the development of high-density, low-cost, high-power, low-power consumption, and high-efficiency switching power supplies. [0004] Most general PFC circuits adopt a constant switching frequency, that is, a constant frequency control method. During the implementation process, the inventor found that when the constant frequency control method is adopted, the constant swi...

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Problems solved by technology

During the implementation process, the inventor found that when the constant frequency control method is adopted, the constant switching frequency must ensure that the inductance core cannot be saturated at any time within a power frequency cycle, that is, the inductance must be guaranteed when the fundamental waveform of the input current is at its peak value. The magnetic core cannot be saturated to ensure that the inductor magnetic core is not saturated at other times, so the switching frequency must be high enough, and the higher the switching frequency of the switching power supply, the greater the loss of the switching tube and the lower the power supply efficiency

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