Design and Control Strategy of LCL-FILTER Based on MMC-STATCOM

ABSTRACT

A new shunt STATCOM based on modular multilevel converter (MMC) was researched, but the performance of modular multilevel converters (MMC) was affected directly by higher harmonic and the circulating current. The paper presents a new topology of modular multilevel converter (MMC), which is based on LCL filter. MMC-STATCOM by combination of LCL was researched based on mathematical model of MMC-STATCOM. Based on it, the values of the leg inductance and filter inductance were redefined. And a parallel filter capacitor has been designed between them. Therefore, a new topology of MMC-STATCOM has been composed which is conducive to output characteristics and the circulating current suppression. The paper researched on the influence of elements on the system, and the algorithm of elements were given. Moreover, a new control strategy based on filter capacitor feed-forward was put forward .The effectiveness and feasibility of the proposed control strategy have been verified by the simulation performed based on MATLAB.

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