The Study On The Topology Of Static Var Generator

Reactive power balance is the key factor to ensure the grid power quality,improve the transmission efficiency and maintain system security and stability. Afterdecades of development, the world has developed a wide range of reactive powercompensation device, static var generator (SVG) relies on the advantage of rapid,stationary operation, security and stability, rapidly occupy a position in the field ofreactive power compensation, absorb the attention by scholars both at home andabroad.The main circuit topology of SVG is the most basic and crucial part of thesystem, has very important significance on its work performance and developmentpotential. This topic will start from this aspect, introduce a variety of main circuittopology that can be suitable for SVG with large capacity. And discuss structuralcharacteristics and working principle of each kind of main circuit, compare theiradvantages and disadvantages. Under the environment of Matlab/Simulink, simulatethe output voltage waveform and spectrum of all kinds of main circuit, and furtheranalysis the simulation results.The cascading multilevel circuit structure, as a kind of SVG topology forms thathas great development potential, has great research value and significance. This topicresearch will focus on this cascading SVG, deduce its mathematical model as afoundation for the research and design, and use this to design the whole controlsystem of SVG, calculate the control parameters. In order to further verify theperformance and characteristics of cascading SVG, build the SVG system model inthe simulation environment, set up devices and control parameters, analyse thesimulation data, the results show that the control system of cascading SVG is reliable,and dynamic compensation ability is outstanding.In the double closed loop control theory, the DC side voltage outer loop controlof cascading structure is difficult to achieve. So this paper puts forward a new kind ofDC side voltage hierarchical control strategy, it not only control the single phasevoltage level as a whole, but also control the modulation signal of each power unit directly from various modulation wave. Realized this kind of control method in theMatlab simulation environment, and the results verify the effectiveness and reliabilityof the control strategy.