Control Strategy Of Unified Power Qulity Conditioner Based On Modular Multilevel Converters

Electric power is one kind of most useful energy for social production and people’s life.With variety kinds of electric appliance equipment popularization, the dependence on electricalenergy is more and more serious. One hand because of the electric appliance equipmentdiversification, non-linear load in electrical network increases day by day and cause seriousinfluence on electrical energy quality, and on the other hand, more and more to get along with avariety of precision instruments and equipment use electricity users are increasingly highrequirements of power quality. The study of power quality became more and more important. Itis UPQC that emerged in this environment.Firstly, this article has conducted preliminary research in view of the influence on electricalenergy quality on each kind of factor and brief analysis has been made to enhance the electricalenergy quality. Simple discussion has been carried on the active electric power filterdevelopment course and the research at present. Derived Instantaneous Power Theory and clarifyits physical meaning, based on it, we investigated the control strategy of active filter, and talkedabout the advantage and disadvantage of it. This article has focused on the control strategy ofUnified power quality conditioner based on MMC after talked about the principle of UPQC.To find the valuable control strategy, both series side and shunt side control strategy arediscussed in detail and a combined control strategy is reached. Modular control solutions wereadopted in the formulation of the control strategy. The one hand, it can simplify the process ofanalysis and design, on the other hand, each of control Modular can change or improveindependently on demand, without affecting the internal functionality of each module, so ensuresystem stability and concentration while its flexibility. The topology and principle of modularmulti-level converter (MMC) is analyzed in this paper for improving the configuration ofUnified power quality conditioner. This paper, under discussed variety control strategy of MMC,analyzes multi-level hysteresis-space vector control method.Finally, under Matlab/Simulink environment, the simulation model of control strategy forUPQC was built. Simulation and analysis of system load with performance of different harmoniccase were carried through UPQC compensation, in order to test and verify UPQC is one of themost flexible devices for harmonic compensation.