Impact of Identical Aggregated LC Output Filters on High-Frequency Oscillation Stability in DC Microgrids

The construction of DC micro-grid is conducive to the nearby absorption of renewable energy. Meanwhile, the increase of power electronic devices in the micro-grid may lead to the occurrence of high-frequency oscillations and other phenomena, which requires the evaluation of the stability of small disturbances during planning. In the evaluation process, the number of micro-power source is approximately proportional to the dimension of the system state matrix, so a large number of micro-power source connections bring challenges to modal calculation. It is necessary to propose a method of order reduction to meet the requirements of small disturbance stability analysis of DC microgrid. In this paper, an aggregated order reduction model for high frequency oscillations is proposed, which reduces the workload of numerical calculation in the process of modal analysis of the microgrid, and is helpful to better evaluate the microgrid in the planning stage. In the last part, simulations are carried out to verify the method for different micropower access quantity and different microgrid topology. The simulation results show that the method proposed in this paper can effectively evaluate the high frequency oscillation risk of DC micro-grid and simplify the difficulty of calculation.