Research On The Topology And Control Technology Of Dynamic Voltage Restorer

In the field of power quality regulation,Dynamic Voltage Restorer(DVR)has become one of the most effective solutions for the voltage sag due to its advantages of fast dynamic response and flexible control system.The key factors to decide and influence the performance of DVR are topology and control technology.With the development of power electronics ant automatic control technology in recent years,there are more method to realize the design of the DVR topological structure and control strategy.In order to ensure the performance of DVR voltage compensation and improve its ability to adapt the complex power grid environment,this paper provides research on the topology and control technology of DVR.Operating characteristics,topology structure and control strategy are core technology of DVR.From the above three aspects,this paper presents the working principle and characteristics of DVR,analyzes and designs the power topology of DVR,and compares the different voltage detection and compensation methods.In order to ensure and improve the performance of DVR in different environment,this paper divides DVR into single-phase and three-phase topology to separately design and research.As for the single-phase topology DVR,this paper builts the mathematical model and puts forward the voltage detection and conrol strategy separately based on the filters and proportional-resonant controller,while the multiple proportional-resonant method is established to achieve harmonic comensation.As for the three-phase topology DVR,this paper puts forward the digital phase locking loop(PLL)in voltage detection and the closed-loop control strategy based on proportional-integral controller in three-phase three-leg topology.To solve the possible problem of three-phase voltage imbalanced sag,the three-phase four-leg topology and the modulation based on third-harmonic injection are designed to realize the establishment of control strategy.Besides the research on the relevant theory about the DVR topology and control technology,the hardware of DVR including sampling module,control module,power module and action module are also designed to complete the the construction of experimental DVR platform with above two kinds of topological structure.Finally,the voltage detection,dynamic response and steady state compensation experiments have been done to verify the theroy proposed in the paper.Research and experimental results show that the proposed theory in this paper about topology and control technology of DVR is correct and feasible,through analyzing and comparing the DVR performance of single-phase and three-phase topology structure in complex power grid environment,it can be concluded that this two different topology have their own advantages,and they both have fantastic capability of voltage compensation and strong adaptability.