Analysis of Constant Power Loads impact on DC microgrid with Distributed Control

CARNAGHI, M.; CERVELLINI, P.; GARCÍA RETEGUI, R.; JUDEWICZ, M. G.; FUNES, M. A.

San Juan

Congreso; 2022 IEEE Biennial Congress of Argentina (ARGENCON); 2022

Sección Argentina del IEEE, el Instituto de Energía Eléctrica (IEE) de la Universidad Nacional de San Juan (UNSJ)/CONICET, y la Universidad de Palermo.

With the constant growth in the number of DC loads, DC microgrids have gained great interest as energy supply systems. In this context, distributed control schemes based on communication and consensus among generation units, emerged as appealing schemes to ensure microgrid stability and robustness. When communications are assumed to have zero transmission delay, the stability of the microgrid can be compromised as a consequence of the nature and power demanded by active loads as constant power loads (CPLs). For real communications, the situation is even more complex since the communication delays impact on the controller performances and may lead to unstable operation. In the literature, the stability analysis of microgrids in presence of time-delays were focused only considering passive loads. Then, the analysis with active loads in the presence of data transmission delay is still pending. Therefore, in this paper, a time-delay model for a DC microgrid with distributed control and CPLs is presented. Then, based on this model, a delay-dependent stability criterion is derived and numerically evaluated in the form of a linear matrix inequality (LMI) problem. This formulations is employed to determine feasible control coefficients in terms of given microgrid parameters values and to evaluate the variation of maximum time delay with the increase in active power demand.