Control of battery storage to improve voltage profile in autonomous microgrid

Abstract

This paper proposes a new control method for battery storage in an autonomous microgrid. The battery output is controlled in such a manner that the bus voltages in the microgrid system are maintained during disturbances such as load change, loss of micro sources or power limit in the DGs. An artificial neural network (ANN) based controller is used to determine the reference power for the battery to hold the microgrid voltage within regulation limit. The pattern of drop in local bus voltage during power imbalance is used to train the controller offline. Depending on the rate of voltage fall, it is switched to power control mode to inject the reference power determined by the proposed controller. After a defined time period the battery power injection is reduced to zero using slow reverse droop characteristics ensuring a slow rate of increase in power demand from the other DGs. The proposed control method is tested for various operating conditions in a microgrid with both inertial and converter interfaced sources.