Research On The Low-Voltage Static Var Generator Based On DSP

With the development of power electronic devices, the forms of load in the power grid increasingly diverse, which causes the serious problems of low power factor. About the field of reactive power compensation, static var generator becomes the latest hot topic because of the fast response speed, smooth reactive power regulation, reliable operating characteristics, precision reactive power compensation and other advantages, SVG represents the development direction of the reactive power compensation device.On the basis of the development of reactive power compensation, paper introduces the definition and effects of reactive power. First introduce the basic principle, reactive and harmonic current detection methods, and current control methods of SVG which based on three-phase instantaneous reactive power theory. To further understand the SVG’s principle, paper builds the model based on the direct control of current in abc coordinate in the MATLAB environment, compares two SVG reactive and harmonic current detection methods:pq method and ipiq method. Taking into account there are inductive load and capacitive load in the power grid, SVG compensation effect in inductive load and capacitive load is simulated on the steady-state and dynamic loads. Consider about the traditional PI control for DC-link voltage exits disadvantages, such as parameters difficult tuning, poor adaptability of dynamic response, paper combines the particle swarm optimization with pi control, proposes a offline PSO-PI control and a online PSO-PI control. In order to test these control methods, the voltage loop transfer function is derived for the control object. Finally, paper shows the design of SVG, and introduces three main units:the control unit, the main circuit unit and signal detection unit.