Active Stabilization of DC Microgrids without Remote Sensors for More Electric Aircraft

DC microgrids are increasingly used in transportation systems such as more electric aircraft. Such applications require small and light systems, and thus, the optimization of passive elements like dc-bus capacitor and filtering inductor is an important issue. It is known that the reduction of dc-bus capacitance may lead to instability of the dc microgrid when tightly controlled loads are employed. To overcome this risk, a seductive solution is to implement a centralized stabilization system in the dc microgrid. Nevertheless, a centralized stabilizer requires a lot of sensors and particularly those providing the load input voltages. The latter is often far from the stabilizer, and fast data transmission lines must be provided. In this paper, an observer is developed for estimating the load input voltages, thus removing the required voltage sensors. Its convergence as well as the stability of the whole system is proved. The validity of the proposed method is confirmed by simulations and experimentations.