Virtual inertia control of wind-battery-based islanded DC micro-grid

The battery-based islanded DC micro-grid possesses low inertia at the moment when the system is disturbed due to the access of a large number of power electric converters. In this paper, to optimize the use of rotational kinetic energy concealed in DC micro-grid, a virtual inertia control strategy for DC micro-grid is proposed through associating DC bus voltage with the speed regulation of PMSG. Take the wind battery-based islanded DC micro-grid for example, this paper analyses the system inertia previously, and then its smallsignal models are derived. The system stability is compared between with and without virtual inertia control and the results demonstrate that the system stability can be enhanced remarkably when the virtual inertia control strategy is added into DC micro-grid. Also the model is established in MATLAB/SIMULINK and the simulation results validate that the virtual inertia control not only can enhance the system transient stability but also can protect the battery and even prolong the service life of it.