Development of a Power Management System for Electric Vehicles with Multiple Power Sources

An electric vehicle can be powered by either a single source or a combination of multiple sources, e.g. lead-acid batteries, solar cells, and fuel cells. Because of energy crisis and environmental protection, coordination of different power sources for an electric vehicle has recently been becoming an important issue. The objective of this paper is to develop a power management system for an electric vehicle powered by the combination of lead-acid batteries and solar cells. The system consists of an intelligent control unit, a switching unit, a sensing unit module, and a DC/DC converter. The control unit processes data and accordingly instructs the switching unit to allocate an adequate power supply to the drive. Experimental results show that the system can coordinate power supplies effectively and suppresses battery current surges to prevent the batteries from deep discharge. Accordingly the longevity of the batteries can be prolonged.