Backup Power Resources for Microgrid

This chapter presents in the first section some general notions on different backup resources for different operating modes (ie, electrochemical batteries and capacitors, fuel cells, and microturbines) whereas important characteristics of lead-acid storage, diesel generators, and utility grid connection are highlighted in the other sections. The lead-acid storage, chosen to be used in this study, is analyzed and some modeling elements are presented. This section provides a model for knowledge leading to a better experimental control of the storage system in the proposed microgrid. The diesel generator is the most common electricity generator used in building-integrated microgrids. Although it is a highly nonlinear system, a brief analysis of operating modes and costs involved can draw conclusions about its use in a microgrid. The last section presents the grid connection as a main backup resource for the grid-connected operating mode of the microgrid. The utility grid connection was studied through a pulse width modulation control and a conventional phase-locked loop structure used from a single-phase signal. An improvement in its low-power operation is provided by the use of a resonant controller.