Three-Phase Voltage Sag Supporter Using Switching Cell Structured AC-AC Converter

摘要

Voltage sag are the most common and cause more economic losses, which is a serious power quality (PQ) problem. To solve these problems, several topology using an extra battery or back-to-back has been introduced. However, these conventional topologies have drawback in cost effective and system reliability. This paper presents a three-phase voltage sag supporter for power distribute systems known as dynamic voltage restorer (DVR), and is employing direct AC-AC converter using switching cell (SC) structure. The AC-AC converter, in proposed supporter, is highly reliable because they can solve the shoot-through, dead-time, and commutation problem of traditional AC-AC converters without voltage/current sensing devices from SC structure. Moreover, the proposed voltage supporter has a good dynamics because it operates immediately by using interphase voltage when voltage sag is occurred in grid. Simulation and experimental results is provided to verify this.