，成果详细信息-凯发网

impedance character as well as relevant impedance criterion is important in thesmall-signal stability analysis of multi-sgage dc distributed power systems, where subsystems are integrated. at the same time, we usually approximately simplify a tightly controlled load-converter as constant power load. in this paper, we focus on the impedance character and impedance criterion in two-stage dc distributed system, which is in fact criterion in two-stage dc distributed system, which is in fact inter-dependent dynamical system with both interaction loop and many individual regulation loops. we verify that minor loop gain method can be directly extended to inter-dependent subsystems, while original impedance criterion cannot. furthermore, we develop a substitutional stability analysis. with this substitutional impedance criterion, we discuss the influence of regulation loop gain, load resistance, input voltage and various duty-cycle ration on system small-signal stability. in additon, we analyze the impedance shift process of the imput impedance of load-converter and build the relationship between it and rgeulation loop gain. negative rgsistor approximation of load-converter is only regarded reasonable when high regulation-loop gain is assumed and low-frequeney character of load-converter is considered. simulation results illustrate the validity of the substitutional impedance criterion.