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DC Capacitor Voltage Control Strategy For Cascaded H-Bridge Based STATCOM

Posted on:2016-04-10Degree:MasterType:Thesis
Country:ChinaCandidate:B QinFull Text:PDF
GTID:2272330461972286Subject:Electrical engineering
Abstract/Summary:PDF Full Text Request
In order to increase the power system’s stability and reliability, the Flexible AC Transmission Systems (FACTS) can improve electrical power quality effectively, which develops rapidly in recent years. As a typical equipment of FACTS, the Static Synchronous Compensator (STATCOM) is paid more attention. The cascaded H-bridge based STATCOM achieves advanced control performance and good compensation effect in high voltage and large power scale compensation. Because the capacitances of each H-bridge in this circuits are independent from each other, it results in the unbalanced voltage of DC-link capacitors as the capacitances charging asynchronously. In order to solve this problem, the voltate dc capacitor voltage balancing control is researched in the thesis.(1) The the principle of reactive power compensation for cascaded H-bridge based STATCOM is analyzed, then the power control strategy is established. The voltage unbalance of DC capacitors is mathematical analyzed. An individual balancing control of single phase and clustered balancing control of three phase are designed based on the charge of capacitance. The individual balancing control can keep the voltage eqalization of DC-link capacitors in the same phase. The clustered balancing control can keep the voltage eqalization of DC-link capacitors in the three phase. The control strategy can play a role not only in the normal condition but also in the unbalance condition.(2) On the basis of the theoretical analysis, the thesis builds the simulation system by MATLAB/Simulink. The thought of the control strategy is proved to be correct by analysis the simulation waveform.(3)A full digital controller is designed by Verilog-HDL.The reactive power compen-tion is validated and the voltage balancing control strategy using the state of charge (SOC) on DC-link capacitors. In addition, The experimental results present the dynamic and static performances of reactive power compensation. Meanwhile, the DC-link voltage balancing control strategy is also verified.
Keywords/Search Tags:Cascaded H-bridge, The Static Synchronous Compensator, The Voltate DC Capacitor Voltage Balancing Control, Field Programmable Gate Array
PDF Full Text Request
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