Research Of Reactive Power Compensation In Low Voltage Power Supply System

The Static Var Generator is a newly developed technology used in the low-voltage reactive power compensation field. With the improvement of power electronic devices, the use of special circuits and the redesign of control methods, the SVG system now can not only conpensate real-time reactive power accurately but also proves good at filling and harmonic suppression. Thus, SVG is becoming an important method in reavtive power compensation.The temporary studies on SVG are focusing on main tructure, the real-time signal detect, system protection and selection of control methods.etc.Based on the analysis of basic principles of SVG, this paper described a three-phrase converter, which forms the main structure of SVG, the detection and process of realtime signals, and circuit protection in detail. By comparison of different plans, a simple but reliable one with a direct current control method, which is based on instantaneous reactive power theory, was chosen. Specific signal detectiong and processing plan was used to realize the compensation of both reactive power and harmonics. The i_p - i_q reactive power compensation method was analysed in detail and the coordinate transformation formulas were listed. In the experiment step, DSP collected all the signal information detected by signal detecting circuit board and gave out the SVPWM pulse signal to turn on or turn off the power switch inside the IPM, where the needed reactive power came from. Finally, specific circuits were set up to validate the program. It came out that the system can both compensate the reactive power and curb harmonics. Thus it might be wildly used in the future.