| The STATCOM now makes one of the most important devices in Flexible AC Transmission Systems (FACTS), whose typical objects is reactive power compensation to grid dynamicly including inductive and capacitive, in addition restrain in voltage fluctuation and flicker, stabilization voltage, improvement resistivity of the grid.In this paper, the development and emphasis on recent research is presented. After analyzing the operating principle and steady-state characteristics of STATCOM, the small signal model based on Synchronously Rotating Frame of Reference is acquired, and the control structure of current loop and outer voltage loop is established, compared with decoupling control about d、 q axis’s current loop to remove the influence each other.Most of research on STATCOM is under ideal grid conditions, the fundamental positive sequence component is converted to constant one based on Synchronously Rotating Frame of Reference, so that PI regulator can control the system accurately with great speed. However, when there is harmonic in grid, the original control plan is deficient because harmonic component is detected in compensating current, in addition, what’s more this situation can be intensify with the increase of the harmonic. In order to solve that question, a novel feed-forward control method importing the voltage of PCC to STASCOM is proposed, which is associate with PI control. The same voltage with grid is copied in AC output side of STASCOM to restrain the impact of harmonic.According to above-mentioned analysis, simulation on STATCOM with harmonic in PCC is performed based on MATLAB/Simulink. with the feed-forward control method or not. Finally, experimental platform based on DSP(TMS320F28335) is established, and the novel method is test. The results indicate that the proposed control strategy make the out current be sine-wave, enhancing the feature of the STATCOM. |
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