Development Of Power Quality Regulating Device Based On DFACTS

In recent years,the use of Rectifier,Frequency Control and speed regulating device, Electric Arc Furnace and Electrified Railway Increases unceasingly.The property of these loads,such as nonlinearity,impact and unbalance,makes the utility current and voltage waveform distorted,at the same time cause many power quality problems like voltage fluctuation,flicker and unbalance.As an effectual method to improve the power quality of distribution network,the research on power quality conditioning device which is based on DFACT,is increasingly taken into account.In the thesis,on the base of relevant documents home and abroad,the background of the DFACTS technology,the current research situation and the development of detecting and controlling methods are summarized.The topology structure of a parallel hybrid Power Quality Regulating Device is put forward,which combines the advantages of both APF and traditional VAR compensating devices.The operational principle and key technology are intensively studied,which focus on the instantaneous reactive power theory(especially ip-iq detecting method),SVPWM technology,capacitor synchronous switching technology.The thesis develops the control system of the parallel hybrid Power Quality Regulating Device based on DFACTS,include hardware circuit and software design.Hardware mainly including DSP control circuit,signal acquisition and A/D converting circuit,IPM with its support circuit,synchronous sampling control circuit.The schematic circuit diagram and detailed exposition of the functions of each part are provided.The C language is adopted in the software design,the flow chart of main programs is given,which mainly include signal acquisition and A/D converting part,detecting algorithm based on instantaneous reactive power theory and control algorithm of SVPWM.On the base of above work,the prototype of this Power Quality Regulating Device system is developed,and the element parameters of the main circuit are determined.Then, experiments are done on the experimental equipment of the proposed Power Quality Regulating Device system,and satisfactory results are drawn,which proved the rationality and practical value of the proposed Power Quality Regulating Device.