| Nowadays, our nation attaches great importance to use high-tech to improve energy.It needs stable distribution grid power quality whether in industrial or householdelectricity consumption. The previous grid compensation devices, such as SVC and TCR,can not adapt to the situation that there is rapid changes in the power grid,and they cannot achieve instantaneous reactive power control. D-STATCOM not only candynamically compensate capacitive or inductive reactive power but also can compensaterapidly changing instantaneous reactive power. Therefore, D-STATCOM has beeninvolved in research and applications increasingly. It has a certain theoretical andpractical value to conducte a systematic study on the D-STATCOM.First, this paper introduced the application of flexible AC technology in improvingpower quality, the development situation and trend of D-STATCOM, the basic structureand working principle of D-STATCOM; then various current detection methods wereintroduced, and highlights the adaptive detection method which uses adaptive noisecanceling technology as its detection principle. And on the basis of three-levelD-STATCOM system, two current control methods such as current indirect control andcurrent direct control are discussed, and summarized the application of the currenttracking control methods; then the relevant principles of SVPWM modulation techniquesand the midpoint voltage control method were introduced.Finally, the paper established three-level D-STATCOM model system usingMATLAB/Simulink. The adaptive detection method and indirect-Current control methodis the main control method of the system, and SVPWM were used to generate pulsesignals in the three-level D-STATCOM model. The experimental results verified that thecontrol methodology can compensate reactive power quickly, no matter in capacitive loador inductive load, or in the case of load changes. |
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