Điều khiển dự báo dựa vào điều chế vector không gian nhằm cân bằng điện áp trên các tụ và giảm thành phần sóng hài dòng điện vòng của bộ biến đổi MMC

Abstract

This paper proposes a predictive control algorithm based on space vector modulation method for the purpose of capacitors voltage balancing and harmonic circulating current suppression of MMC. The modulation methods are built on the basis of SVM for an MMC with the capability of achieving an voltage with unlimited number of levels at the AC side. The loop current circuit uses PI regulators and PR resonators to eliminate even-order harmonic components such as 2nd and 4th of the circulating current to retain only a DC component that transmits DC power. Predictive model browses all the residual status vectors, combined with the adjusted voltage from the circulating current to ensure the smallest deviation from the average voltage value established for the upper and lower branch of capacitors, on all three phases of the MMC. The voltage value on each capacitor in the branches is balanced with each other by a separate algorithm, these capacitors are inserted or ignored in each modulation cycle accordingly.