A novel double loop control design and analysis of STATCOM

The static synchronous compensator (STATCOM) based on voltage source converter is one of the most used FACTS device. The primary purpose of a STATCOM is to support busbar voltage and maintain the stability of the DC-link capacitor voltage. In this paper, the operating principle and model of STATCOM are introduced, and a novel double loop control strategy of current feed-forward plus double PI loop for adjusting transmission line real power is proposed. Busbar voltage outer loop control system adopts voltage droop control which consists of PI regulation and scaling factors of droop characteristic. A current feed-forward control is introduced into double loop de-coupled control system of DC capacitor voltage regulation. Designing process of control system is discussed briefly in this paper. The simulation results for a case study indicate that DC capacitor voltage and busbar voltage can be controlled efficiently, attest that control scheme and controller design are viable and effective. It is also proved by the experimental results on a 15-kVA laboratory-scale equipment