Research Of Microgrid Seamless Transfer Strategy

With the increasing depletion of energy and environmental issues become prominent, distributed generation as an effective way to solve these problems has been booming. The microgrid, as an effective carrying way of distributed generation, can fully take advantages of distributed generation and support each other with the grid, which makes users obtain uninterrupted reliable power supply. The microgrid seamless transfer between grid-connected mode and islanding mode is the premise of ensuring the normal operation of sensitive load in microgrid, which becomes one of the important contents of microgrid research.According to the microgrid seamless transfer control problems, the traditional droop control strategy is studied. By improving the traditional droop control strategy and introducing the adaptive control, this paper puts forward an adaptive droop seamless transfer control strategy to achieve the microgrid seamless transfer between grid-connected mode and islanding mode. The main research contents are listed as follows:1. The microsource interface control strategy is detailed expounded in this paper. Each module is analyzed in terms of the microsource inverter interface modeling, instantaneous power calculation, the basis of droop control strategy, the voltage and current dual-loop decoupling control theory and the voltage space vector pulse width modulation control method.2. The traditional droop control strategy is presented. Based on the traditional droop control strategy, an improved droop control strategy is proposed and the improved droop controller mathematical model is built. By introducing the adaptive control into the proposed control strategy, an adaptive droop seamless transfer control strategy is proposed;3. The implementation of microgrid seamless transfer control method is given. Through the MATLAB/Simulink modeling and simulation, the adaptive droop seamless transfer control strategy is verified and comparative analysis between the traditional droop control strategy and the proposed strategy has been carried on.Through the research of introducing the adaptive control into microgrid cooperates to the traditional droop control strategy to realize microgird seamless transfer process, the conclusions are as follows:the adaptive droop seamless transfer control strategy can achieve microgrid transition between grid-connected and islanding mode; the adaptive droop seamless transfer control strategy can ensure the microgrid load obtaining uninterrupted reliable power supply.