Operation of a Dc/3ϕ power converter using a single-delta bridge-cell converter under low magnetizing inductance

Abstract

A single‐delta bridge‐cell converter (hereinafter referred to as an SDBC converter) is a prospective power converter for a static synchronous compensator (STATCOM). The authors have proposed a dc/3ϕ power converter using the SDBC converter and a medium‐frequency single‐phase transformer with an operating frequency of 150 Hz; this converter can exchange a maximum active power of 37% of the rated reactive power with three‐phase ac mains supply without increasing the voltage and current ratings of the SDBC converter. In particular, the negative‐sequence reactive power control is a challenging task because of the high magnetizing inductance of the transformer. To achieve the negative‐sequence reactive power control, a single‐phase transformer with low magnetizing inductance is applied to the converter at the expense of the exchangeable active and reactive power. The relationship of the magnetizing inductance, active power, and reactive power is revealed in this paper, and the operation of the converter under low magnetizing inductance is experimentally verified by employing a downscaled 110‐V, 7‐kVA model.