Control of nested DC-link voltage for dual three-point StatCom

Static synchronous compensator (StatCom) is normally involved a voltage-sourced (VS) inverter because of its smaller volume and lightweight of DC-link capacitor. Voltage-sourced type of StatCom works largely on the stable voltage crossing the condenser of DC-link circuit. The introduced control strategy is based on the concept of keeping the DC-link voltage at an appropriate level, so it can easy control sending reactive power to system or absorbing reactive power from system. This manner of control is described according to voltage vector of three-phase AC system and the analysis in the time-domain. The configuration of dual three-point StatCom and its realization idea are discussed; the realizing idea of this type StatCom could be used in high voltage level. At last, the simulation results are given, and the comparison between simulation and idear results has been made also in this paper.