| Power Electronics System Integration (PESI) has been being an important development trend in power electronics. The aim of this dissertation is to research the impedance of DC/DC converters, which is a small part of the PESI project. It is very important for standard topologies selection, stability estimation for cascaded power electronics system, as well as the constitution for the impedance standard of DC/DC converters.The input and output impedances of the voltage mode controlled DC/DC converters under CCM operation are firstly analyzed. The influences of the loop gain and parasitic parameters on the impedances are discussed, and the requirements to the loop gain and parasitic parameters are presented in order to improve the impedance characteristics.It is helpful for analyzing the impedance characteristics with the exact and dependable experimentally measured impedances. A detailed review and comparison with various impedance measuring methods are discussed. Based on the comparison, an improved impedance measuring method with a wide impedance range for DC/DC converters is proposed. And some factors to infect on the measured impedance result are discussed and the solutions are also proposed.To verify the theoretical analysis, the impedance measurement is specially carried out on a ZCT full bridge converter. The results show that the proposed measuring process can be used to analyze other DC/DC converters too and the impedance characteristics of the ZCT full bridge DC/DC converter can be as a standardized one. |
