Study And Design On Static Var Generator In Low-voltage And Three-phase Four-wire System

In recent years, with the development of power electronics apparatus and nonlinear load in low voltage power supply system in a wide range of applications, harmonic and load balancing problems in three-phase four-wire system have become increasingly prominent, especially in the zero sequence current on power system have great harm. For the power and power system reactive power compensation of three phase four wire system, this article has conducted the research and the design of low voltage SVG in three-phase four-wire system.This paper first briefly introduces the reactive power compensation of power system development and current situation; then the principle of SVG is analyzed, and the study of three-phase four-wire SVG main circuit topology, through comparative analysis, finally four bridge arm topological structure is used; Then according to the three-phase four-wire system reactive current detection methods were compared and analyzed, finally took the ip-iq current detection methods, and to improve it, namely the separation of zero sequence current method, this method is based on the theory of instantaneous reactive power, and can be very good for three phase four wire system the reactive current detection; then the SVG control algorithm was studied, and the design of the triangle wave PWM control algorithm for the system of DC side voltage control, and the use of PI regulation, maintaining the DC side voltage stability. Finally to TI's DSP digital signal processor ( TMS320F28335 ) based on three-phase four-wire system SVG control system hardware design and software design, and through the MATLAB simulation, the experimental results show that the design method can well compensate the reactive current, and is capable of three-phase unbalanced current compensation, thereby eliminating the zero sequence current.