The Research On The Strategy Of Unified Power Flow Controller With Variable Structure Control And Fuzzy Control

Unified power flow controller(UPFC),as one of the most representative FACTS devices,has great development potential.It has a fast dynamic response and good control performance.We can compensate the power of the grid and maintain the bus voltage by controlling the UPFC.It is very important for us to study the UPFC.UPFC can ensure the stability of the bus voltage and the capacitor voltage by adjusting the current of the parallel converter.UPFC can compensate the power of the grid by adjusting the voltage of the serial converter.The control performance depends on its control strategy.This essay makes a deep research on the control strategy of UPFC.The mathematical model of UPFC is a system with many variables and strong coupling in the dq coordinate.The essay can decouple the model of UPFC in the dq coordinate by adding a transformation from dq transformation to ?? transformation.Then we use the variable structure control theory based on fuzzy reaching law to design the controller of the UPFC.According to the strategy,the UPFC can compensate the power of the grid and maintain the stability of the bus voltage.In order to test the performance of the controller designed in this essay,we build the simulation model of UPFC through the MATLAB/SIMULINK simulation software.As the graph revealed,the controller designed in the essay can make the UPFC quickly and accurately compensate the power of the power system and maintain the bus voltage.At the same time,we also use the variable structure control theory based on the inverse system to design the controller of the UPFC.By comparing two different methods of simulation graphics,the first type of controller has a larger advantage in speed and accuracy.