| With the evolvement of power processing technologies, building large-scale distributed power systems (DPS) has become a reality. However, due to the lack of standardized power electronics modules, the cost is difficult to be cut down and the reliability of power electronics modules can not be highly ensured. Until the advent of the power electronics building block (PEBB) concept proposed by US Navy, the significant paradigm shift in power electronics technologies can be achieved. US Navy's contribution to the system integration is that they proposed and implemented PEBB concept at the modular level. This paper presents a novel concept for the system integration at the system level, which is to select the output impedance of the source converter and the input impedance of the load converter as objects of standardization. The purposes of this paper are of two-fold. Firstly, it characterizes and reveals the characteristics of input and output impedances of power electronics converters. Secondly, it provides experimental evidences to verify the theoretical analysis to facilitate issuing the input and output impedance specifications of buck-type dc-dc converters for the future.This paper is organized as follows. Background information and the introduction to this interesting topic are given in the chapter I. The mathemaitical model of the input and output impedances of buck-type conveters are derived in the chapterII. ChapterIII reveals characteristics of the output impedance of buck-type dc-dc converter, with phase-shifted full bridge dc-dc converter as an example. And the influence of three factors including the output power rating, the switching frequency and the control-mode on the output impedance of the phase-shifted full bridge converter are presented in this chapter. Furthermore, experimental measurements of the closed-loop output impedances of several prototype converters are given to validate the theoretical analysis at the final section of this chapter.Based on the same research philosophy given in the chapterIII, Chapter IV firstly reveals characteristics of the input impedance of buck-type dc-dc converter, with synchronous buck converter as an example. Secondly, the influence of three factors including the output power rating, the switching frequency and the control mode are also presented. Finally, experimental measurements of the closed-loop input impedances of several prototype converters are given to validate the theoretical analysis.In order to elimate the current hamonics, which are produced by the discontinous input current of back-end laod converter, the input filter should be employed to smooth the input current and reduce the EMI of cascaded power system. Thus, chapter V discusses design considerations of the input EMI filter and two design examples are given and verified by the experiment. The experimental results show that the EMI input filters do not derteriate the stability of cascaded power system, but they do derteriate the dynamical performance of cascaded power system a little. So there exists the trade-off between the input ripple current and the dynamical performance of the cascaded power system.
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