Research And Implementation On Dynamic Voltage Restorer In Microgrid

With the growing shortage of energy and the society to pay more attention to environmental protection, new energy and renewable energy use to become the current hot spot. Micro-grid supported by distributed generation and energy storage technology has been applied, micro-grid’s structure and operation mode has many new features,compared with the traditional distribution network in power quality control.Based on the analysis of micro-grid structure, a targeted research is on the common connection point for micro-grid and distribution network of voltage sags, and the paper presents a dynamic voltage restorer (DVR) suitable for micro-grid. It is analyzed of the conventional DVR topology structure, focused on the analysis of the inverter unit and energy storage unit, and is improved in terms of energy storage.Then,the paper chooses the suitable topology for micro-grid DVR. And the parameter design of main circuit are discussed.The generation process of DVR voltage compensation instructions is studied. Using the principle of minimum energy compensation strategy, combining with the characteristics of dqO detection strategy, the reference voltage generation process of the minimurn energy compensation strategy are given in detail. At the same time, the phase lock loop(PLL) which is playing an important role on the instruction generation voltage are analyzed.It was introduced in detail the phase-locked loop based on double synchronous coordinate decoupling software.The paper describes the control method of DVR. Combining with the characteristics of the feedforward control and the double closed-loop control method, this paper proposes a double loop control method based on PR controller,as the control target of the strategy, the load voltage can track the reference voltage steadily.The paper builds the DVR prototype experiment platform of the micro-grid,and the control strategy and the compensation strategy is verified. The minimum energy compensation method is also verified in resistance load and resistance inductance load.The main circuit device is choosed according to the main circuit parameters and the DVR model. Then through rational layout and connection, the construction of the experimental platform is completed. Finally it is introduced that hardware design and software design of the DVR experiment platform, and experimental verification of the DVR prototype are given.