Research On Simulation And Application For Dynamic Voltage Restorer

As industrialization accelerates,the requirement to the electric energy quality of user has been more and more rigorous.Voltage sag is the most harmful power quality problems with the highest frequency.At present,dynamic voltage restorer is one of the most effective and economical methods to solve the problem of voltage sag.According to the working principle of the dynamic voltage restorer dynamic,this article carried on the design of voltage restorer topology structure,control strategy,and compensation strategy.In terms of voltage detection,The article put forward three kinds of methods which was three-phase park transform,dummy symmetry three-phase park transform,single-phase transform based on the derivation method.The three-phase park transform is not applicable to single phase,but in the power grid,the voltage sag problems often occurred in single phase.The single phase transform is evolved from dummy symmetry three-phase park transform,reducing the amount of calculation.This article separated positive-sequence component,negative sequence component,zero-sequence component from three-phase voltage on basis of instantaneous reactive power theory..In the aspect of control strategy,comparing the bode diagram of PI controller and PR controller.The article proved that the PR controller had good frequency characteristic.This paper also proved that the modified PR controller can increase the bandwidth.At the same time,PR controller with functions of harmonic compensation was proposed.Synthesizing analysis of the control strategy through bode diagram,the article adopted the feedforward and feedback complex control strategy.On the basis of complete compensation strategy,The simulation experiment is done to the voltage sap,phase shift and harmonic interference through the MATLAB/Simulink respectively.