A New Method of Compensation Current for DSTATCOM Under Asymmetrical Three-phase Voltage

A new detection method based on synchronous reference frame is proposed. A single-phase voltage is derived and used to form virtual symmetrical three-phase system. Sine signal and cosine signal are formed in this reference frame. It substitutes the low pass filter by simple integration,delay and gain,which can reduce the detecting delay to 1/6 of source period. The compensation current is derived,which is more accurate than in unbalance voltage conditions. This method needs simple calculation without the phase-locked-loop and can meet load compensation demand of DSTATCOM under asymmetrical voltage conditions. The real-time and effectiveness of the detection method as well as better compensation of compensation currents are verified by simulation results.