Integrated battery management system employing multi-port DC/DC converter for standalone solar photovoltaic system

Abstract

ABSTRACT The standalone solar photovoltaic (PV) systems employing multiport converters utilize battery as buffers to handle excess or deficit solar PV power. However, a review of literature has shown that often no battery management unit in the control schemes of multi-port converters used in such hybrid systems and also there is an abnormality in the levels of battery voltage. The battery management unit systems are essential to maintain battery at safe operating limits of current and voltage. This paper proposes one such unit for a standalone solar PV system make use of a single inductor, dual input/output DC-DC converter along with the developed time sharing control scheme. It consists of a battery management unit scheme that implements the standard three-stage charging process. The battery management unit is integrated into a dynamic power management scheme for a standalone solar PV system which consists of combined voltage control and MPPT control. Further, the reduction in solar power of around 50% makes the voltage controller to adjust its duty ratio by almost 50% of its previous value to maintain the constant load power. The built in experimental setup in the laboratory validates the working of the proposed battery management system.