Abstract: Along with the enlargement of the actual application of DC-DC converter, people put forward the higher requirement to the stability of converter system. Thus, accurate and effective modeling and simulation are of great significance to the development of converter. Taking Buck circuit as an example, this paper presents two new kinds of models called hybrid bond graph model and average bond graph model. The two models are all derived from basic theory of the bond graph modeling, but they differ in the control mode of circuit switch. First, through the analysis, the two kinds of bond graph models are achieved, and are built in the GME (Generic Modeling Environment) software. Then, they are automatically converted to Matlab diagram model through the software and simulation in Matlab. At last, by comparing and analyzing the simulation results with the actual output waveform, the correctness and feasibility of the two models are verified.

Key words: bond graph, power electronic circuit, hybrid bond graph model, average bond graph model