Research Of Analytical Model Of Buck Converter Based On Per-unit Method

Buck converter is a typical step-down DC-DC converter which is widely used in switching power supply,new energy generation,low voltage power supply and other occasions,it has a higher research value and application value,hence,the theoretical study of Buck converter has some practical significance and guiding effect.Firstly,the paper describes how Buck converter works,analyzes the Buck circuit separately in continuous conduction mode and discontinuous conduction mode and introduces several commonly used control modes and modulation modes of Buck converter briefly.Secondly,based on the deduction of the physical equation of the Buck converter,the basic current equation and energy equation of the Buck converter are proposed,and based on which,the inductance and average current of the inductor in critical CCM are deduced.When substituting the relative inductance,relative load and relative inductor current into those two basic functions,the relative current and energy functions of the Buck converter are proposed,taken the relative inductance as independent variable,the analytical solutions for inductor current in CCM and DCM are proposed separately,on the basis,the minimum and maximum inductor current and the duty ratio are discussed and the inductor current equation is analyzed by using Fourier transformation.Finally,simulation and experimental results are presented to verify those formulas.