| The application of power energy storage technology in power quality controller is an effective method of solving power quality problems. As a novel energy storage component, supercapacitor has some advantages, such as the fast response, high charge-discharge efficiency, good environmental protection characteristic and so on, which enable its potential of widely application in the domain of power quality control.In order to study the effectiveness and feasibility on the application of electric energy storage system to power quality improvement, supercapacitor component is selected as the main research object in the thesis. The operating characteristics and related technologies are analyzed. A supercapacitor DC energy storage control system is built and DVR (Dynamic voltage restorer) equipment model based on the application of surpercapacitor is designed.According to the relative analysis of all kinds of power energy storage technology, the feasibility and superiority of the application of supercapacitor in power quality controller is studied. The operating characteristics and advantages of supercapacitor are described. Moreover, related technologies of supercapacitor which include charging,discharging modes, voltage balancing methods and so on are given.Supercapacitor DC energy storage control system is consist of supercapacitor bank and BDC converter. Based on the state-space average method, a small signal linear mathematic model of control system is built. According to the mathematic model, a composite control strategy which includes feedback and feedforward control methods is utilized in the thesis. The simulation results show that the composite control strategy can realize the bi-directional power flow control and stabilization of DC bus voltage.There are two energy obtained methods in DVR, advantages and disadvantages of them are analyzed. Based on the main circuit topology of DVR, a DVR simulation model including supercapacitor DC energy storage control system is built. Moreover, a simple algorithm for the the calculation of the energy storage capacity in the DVR is utilized. Later, a series of simulation experiment including voltage sag,voltage swell and harmonics are implemented. The simulation results show that the application of supercapacitor in the DVR is feasible and effective. |
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