Design And Realization Of The Series Converter Of UPQC

With the development of morden science and industy ,power system,customer,power facility producer are all concerned with the power quality problem .DFACTS system ,which is based on the technology of power electronics for power distribution area has become an effective measure to solve power quality problem. The series converter of a three phase four wire UPQC system is studied in this thesis ,the main content of this paper as listed below.Firstly, based on the power circuit and system performance of the series converter of UPQC,the operation principle of the system is analyzed. Then ,according the demand of this paper , three phase four wire UPQC system is chosed as the study object.Secondly,the mathematical models of series converter of UPQC are established in ABC frame and dq0 frame.The models show that each phase of the three-phase four-wire series converter is individual in ABC frame and 0 axis is independent of dq axis in synchronous frame. The control strategies for series converter are discussed with ideal or non-ideal input voltage. For suppressing the influences of non-ideal input voltage, three effective control methods are introduced. The first is three-phase ABC individual control, the second is dq0 axis control, the third is the harmonic of input voltage forward feedback control. Based on MATLAB SIMULINK environment, a circuit modeling simulating method is introduced.Finally, Finally, a 10kVA power circuit of the series converter of the three-phase four-wire UPQC and its coordinated control system based on DSP is designed . A large number of experimental results are obtained when the series converter operate by itself and in the UPQC system,the results prove that the series converter can effectively improve the current quality of power system .