Design and Implementation of Autonomous Low Voltage DC Microgrid with Hierarchical Control

Abstract

Microgrid facilitates the large scale integration of renewable energy sources (RESs). But non-dispatchable characteristics of RESs have raised serious challenges in microgrid control. The issues like intermittent generation, low fault levels etc. demand critical control of microgrid. In rural electrification, the low voltage DC microgrids are getting edge over the AC microgrids due to inherent simple configuration and control. The droop control in DC microgrids is simple to implement, but lack inherently in optimal power management and dynamic response. This paper provides some insights into the design, development and testing of an autonomous DC microgrid with a two-level hierarchical control. The primary control for power sharing incorporates microgrid sources voltage-current droop characteristics. The supervisory control provides microgrid bus voltage regulation and overall energy optimization of the microgrid. This paper presents some key hardware results.