Stabilizing Frequency On Micro-grid With Multi-sources Based On Improved Droop Control

As the symbol of human's civilization, developing and utilizing power is always significant behavior in people's life, and now, the consumption of power have rised to a new level that there were never been in history, under the background of economic globalization. The fossil energy is going to run out, but, that's the major power we can consume. For subsistence, the technology of developing clean energy is researching with the pressure of environmental pollution, and the deficit of energy.In the future, the clean energy will must be the major power we can utilize, so more and more countries have spent huge financial resource for grasping the technology, especially the developed countries and those rich developing countries.At first, this article have introduced the major inverter's control technology, and then, contracted every means for evaluating its advantage and disadvantage. By the limit of costing and the inverter's characteristic, the droop control is suited to control inverters, so, this article would study the new technology of droop control. Based on the previous research, the new method I proposed have the ability of auto-adjust. By using simulation software, the result indicated that the redesign method could control the two parallel inverters output voltage and frequency with high quality and the effect of power decoupling, power distribution is fine.Secondly, this article have discussed the cause of disturbance. For studying the system's stability more detail, I have design the system's small-signal mode, and selected the first method of Lyapunov as the criterion of judging the stability. Because the micro-grid in structure, load form and capacity. For this research, Chapter IV have corrected the small-signal mode, and integrated the redesign droop control method to propose a new method to stabilize the frequency. This method have considered all kinds of disturbance the load would cause. EMS of micro-grid could regain the frequency by control the batteries, inverters and controllable load.Finally, by utilizing the Matlab/Simulink software, this article's new method have been verified. The result have indicated that, multi-power sources could stabilize the frequency after disturbance, EMS have three level measures for improving the quality of power. In addition, in the progress of adjusting the power sources, voltage flickering could be avoided by the redesign droop control method. The micro-grid could run with good effect.