Analysis of Power Sharing by Battery and Ultra-capacitor in dc Microgrid

Abstract

Renewable sources are becoming more popular these days. These renewable energy sources are intermittent in nature. To satisfy the load demand some storage devices like battery are required which is in the form of dc. The dc microgrid is found to be suitable for remote areas and the low power domestic consumers, where electricity is not transmitted by conventional grid. Battery have low power density, the charge/discharge rate is low. Therefore, during quick load fluctuation battery is under high stress, reducing the lifetime of battery. Ultra-capacitor has high power density and it react quick to load fluctuation. In this paper the combination of battery and ultra-capacitor is used and various cases according to state of charge of battery have been studied to meet the energy demand. Sharing of load current by battery and ultra-capacitors during the transient conditions helps to reduce the stress on battery.