Study On Static Var Generator Based On Cascade H-bridge

In recent years, with the development of the power electronic devices, theincreasement of eliminating harmonics and reactive power makes the power qualityserious decline. Rapid local reactive power compensation has important practicalsignificance to improve power factor and reduce the capacity of powered devices.The Static Var Generator (SVG) with its advanced control algorithm and goodcompensation effect has been drawn more and more attention. To solve the problemof high voltage reactive power compensation, the static var generator based oncascade H-bridge was designed and it was suitable for high voltage situations.Firstly, this dissertation briefly introduced the background and the developmentstatus of reactive power compensation in power system. Then the circuit feature andworking principle of SVG were expounded and the SVG’s mathematical model wasset up. According to the model, the dissertation taken coordinate transformation forcurrent detection which based on instantaneous reactive power theory, and taken thevoltage and current double-loop control strategy. Then the carrier phase-shiftedtechnology was depicted, and according to it the double-polarity carrier phase-shiftedtechnology was chosen. Next the dissertation analyzed how control the DC-voltageof SVG, and took a hierarchical control method which was very simple, easy torealize and can achieve proper permeability.The system was verified by the software MATLAB and the SVG simulationmodel of cascaded6H-bridge was set up. Finally. The paper chose TMS320F2812and FPGA as the core controller, and designed hardware circuits and softwareprograms of the SVG’s control system; The test results show that the design methodchosen has a good compensation effect.