Low output ripple wave parallel power-factor correction (PFC) transform control method and device

Abstract

The invention discloses a low output ripple wave parallel power-factor correction (PFC) transform control method and device. The output end of a single-phase PFC convertor (TD) is connected in parallel with the output end of a DC (direct current) / DC convertor (DC-DC), and meanwhile energy is supplied to a load; the output positive end of the single-phase PFC convertor is mutually connected with the output positive end of the DC / DC convertor so as to form a 'Vo+' end, and meanwhile, the 'Vo+' end is connected with the positive end of the load; the output negative end of the single-phase PFC convertor is mutually connected with the output negative end of the DC / DC convertor so as to form a 'Vo-' end, and meanwhile, and the 'Vo-' end is connected with the negative end of the load; an input power supply of the DC / DC convertor is an auxiliary power supply; and an input source of the auxiliary power supply can generate the output of a rectifier circuit (REC), and the single-phase PFC convertor (TD) also can generate the output of the rectifier circuit (REC). The control method provided by the invention has the advantages of eliminating double line frequency output ripples of the traditional PFC convertor, meanwhile, improving the dynamic response of a system, and overcoming the problems that the traditional two-stage power-factor correction convertor is low in efficiency and high in cost.

Description

technical field [0001] The invention relates to a low output ripple high efficiency PFC converter design method and a device thereof. Background technique [0002] In recent years, power electronics technology has developed rapidly, and power supply technology, which is an important part of the power electronics field, has gradually become a hot spot in application and research. Switching power supply has established its mainstream position in the field of power supply because of its high efficiency and high power density, but there is a fatal weakness when it is connected to the power grid through a rectifier: the power factor is low (generally only 0.45 to 0.75), Moreover, a large number of current harmonics and reactive power will be generated in the grid to pollute the grid. There are two main methods for suppressing harmonics generated by switching power supplies: one is the passive method, that is, using passive filtering or active filtering circuits to bypass or elim...

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Problems solved by technology

Therefore, the cut-off frequency of the DC output voltage feedback control loop of the traditional active power factor correction converter is low (generally only 10-20Hz), which seriously affects the dynamic response capability of the power factor correction converter to load changes.

In addition, since the DC output voltage ripple of the active power factor correction converter is relatively large, it is necessary to connect a DC / DC converter to the output terminal of the power factor correction converter after connecting an output capacitor with a large capacitance value. Improve the steady-state accuracy of the load DC output voltage and the dynamic response capability to load changes, making the converter design cost high and low efficiency

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