Feasible enhancement of a three-phase soft-switching inverter with an auxiliary resonant DC link snubber.

The purpose of this paper is to improve power conversion efficiency of a three-phase voltage source type soft-switching inverter with a single auxiliary resonant DC link (ARDCL) snubber. First, the operating principle of an ARDCL snubber discussed here is described. Second, this paper proposes an effective pulse pattern generation method of the zero voltage space vector of the three-phase soft-switching inverter using IGBTs or power modules that can reduce power losses in the ARDCL snubber treated here. In particular, a zero voltage holding interval in the DC rail busline of this three-phase soft-switching inverter is to be regulated according to the generation method of the zero voltage space vector. Third, the maximum modulation depth Mmax under the condition of correction of the instantaneous voltage space vector can be improved by using a new zero voltage space vector generation method. Finally, the feasible experimental results of this inverter are obtained confirming the operating characteristics such as power conversion actual efficiency, as well as conventional efficiency THD and RMS value of the balanced three-phase output voltage for an experimentally built three-phase voltage source type soft-switching pulse modulated inverter using the latest IGBT modules and evaluated from the standpoint of practical applications in industry UPS and new energy systems. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(1): 89–99, 2004; Published online in Wiley InterScience (<URL>www.interscience.wiley.com</URL>). DOI 10.1002/eej.10234 [ABSTRACT FROM AUTHOR]