Modulation method of four-tube Buck-Boost converter

The invention relates to a modulation method of a four-tube Buck-Boost converter, and belongs to the field of electric energy conversion. The main method comprises a duty ratio compensation method in the mode switching process of the buck-boost converter and a double-edge staggered duty ratio modulation strategy, and smooth switching of the four-tube Buck-Boost converter among different modes can be achieved. In order to improve the conversion efficiency, an existing four-tube Buck-Boost converter modulation strategy usually adopts different working modes under different working conditions of voltage increasing and voltage reducing. And in some occasions with relatively high requirements on the stability of the output voltage, the mode switching may cause the fluctuation of the output voltage. The modulation method provided by the invention is suitable for an occasion with a relatively wide input voltage conversion range, and solves the problem of stability of mode switching of the multi-mode four-tube Buck-B