Study Of Statcom Based On Direct Current Control Method

With the rapid development of the industry in our country, quick increase of all kinds of electric power loads, the requirement of the power quality also improves continuously, and the reactive compensation of power quality becomes more and more important. Realizing dynamic reactive compensation by Static Var Compensator(STATCOM) is one of the most active areas in the area of power electronics, and it is also the trend in solving the problem of static var compensation.In this thesis, firstly, several existing reactive power compensation equipments are introduced and compared, while the advantage and the trend of STATCOM are also presented. Additionally, the thesis expounds the fundamental principles, operating characteristics, typical control method and the common method of detecting the reactive current. Secondly, the indirect current control method of STATCOM and its derivative control methods are introduced briefly, including their principles and disadvantages. At last, the direct current control method is researched in details, and several control schemes of direct current control which includes the current hysteresis comparison control and triangle wave comparison current control is compared and researched particularly, while the research is concentrate on the application of parabolic current control (PCC) in STATCOM and the simulink model and of STATCOM system is also built.The simulating waveform of using the PCC as the current control scheme of the STATCOM is provided, which includes the waveforms of capacitive load, inductive load and rectifier load. The simulation result demonstrates that using PCC as the scheme of current control and ip-iq method as current detecting scheme in STATCOM can bring fast response speed and accurate control exactitude.