On Linear Modeling of Switched-Mode Power-Processing Cells and its Applications

The review of the fundamental ideas on which the linear dynamic analysis of switched-mode power-processing cells is based shows that the low-frequency and the small-amplitude restrictions combined which the notion of the controlled quantity permit the establishment of a truly general linear model of these structures with time-varying topology. The model obtained comprises two dependent generators and two impedances defined by means of six characteristic coefficients. The topology of the model is invariant, and is independent of the original cell structure, operating mode and the choice of the controlled quantity. The model describes all essential low-frequency, small-amplitude properties of the original cell and can be used for general dynamic analysis of power supplies utilizing switched-mode power processing cells. The characteristic coefficients defining the model parameters can be tabulated for repeated use and thus a library of data on the dynamic behaviour of various cells can be established. Tables presenting characteristic coefficients of a selection of switched-mode power-processing cells of various structures, operating in different modes and with most popular controlled quantities, are given. The use of the tables is demonstrated using examples based on the general analysis of the switched-mode power supplies. The linear cell model synthesized by the characteristic coefficients method is compared to the linear models obtained by other methods. It is explained that the models resulting from these researches can also be used in the tables of characteristic coefficients.