低压静止无功发生器的研究与实现-机械电子工程专业论文.docx

II II Abstract Abstract With household appliances and precision machines being sharper and sharper for power quality, the importance of reactive power compensation is brought to a new level. Static Synchronous Compensator (SVG) is the most advanced reactive power compensation equipment at present. Comparing with traditional equipment, SVG has superior performances. It has become the hot topic in the research of power electronics. The application and research of SVG technology have made some progress in high-voltage and high-capacity power transmission system, however, only a few SVG are implicated to low-voltage load where the power quality problem is extrusive. Based on the characteristics of low-voltage load, a low-voltage SVG that suits for low-voltage load is designed. The principle of SVG is elaborated in detail. The main circuit configuration of voltage-type SVG is analyzed. Then, mathematical model is built by input/output method. After comparing and analyzing traditional power theory and instantaneous power theory, three reactive power current detection methods based on instantaneous power theory are deduced at length. d-q method is used to detect the reactive power current.At the same time puts forward the comprehensive starting strategy. Effectively reduce the SVG impact current when closing. Direct-current control strategy and indirect-current control strategy are introduced. However, direct-current control is more suitable for low-voltage SVG because of its faster response and higher precision. Under rotary coordinate system, an id-iq decoupling method is applied, then three AC currents are changed into two DC currents for individual control, at the same time, the active and reactive currents are coupled, the output currents can be regulated without steady-state error SVPWM is adopted to drive switch, because it has high utilization of DC voltage, low switching loss, and less harmonic content. A simulation model based on this method is built in the MA