A Review on Modeling of Switching Converters and Their Control Loops

Modeling methods of switching converters and their control loops were summarized and concluded. Meanwhile, classifications for modeling methods of switching converters were given: continuous modeling and discrete modeling; modeling methods based on circuit analysis and modeling methods based on mathematical derivation. According to these classifications, modeling methods of switching converters and their control loops can be combined and further classified as: average modeling, discrete modeling and modeling methods considering sideband effects. On the basis of this classification, principles and characteristics of average method, discrete time method, sampled-data method, describing function method, multiharmonic small signal method and harmonic state space method were analyzed systematically. The differences and relations of various modeling methods were revealed, as well as their merits and demerits were compared which illustrated the applicability of various modeling methods. Taking the most widely used average method as an example, firstly, the equivalent circuit model of basic switching converter was obtained based on time average equivalent circuit modeling, and eight complete transfer functions of power stage were deduced. Moreover, the general gain of sample and hold effect was proposed to figure out that average model ignored the subharmonic oscillation and the traditional gain cannot be used in different average small signal model. Finally, review conclusions and research prospects were presented. © 2020 Chin. Soc. for Elec. Eng.