DC microgrid optimal storage distribution using a conductance and energy state modeling approach

Microgrids with significant renewable penetration will likely require storage devices to maintain a stable bus voltage due to the stochastic behavior of renewable sources and grid loads. The distribution and frequency response characteristics of the storage are two important variables when designing these types of microgrids. For example, storage can be distributed at renewable sources located centrally on a common bus, or a combination thereof. Storage devices will need to compensate for both long and short period disturbances such as the changing output of a photovoltaic (PV) array and the switching of large loads. Simulation results indicate that a cost function based on bus voltage stability is suitable for computing optimal converter capacitances when the load contains cyclic transients.