A study of charging control of lead-acid battery for electric vehicles

The object of this paper is to investigate the circuit topologies and control techniques for fast charging of battery for the electric vehicle (EV). Analysis and comparison of fast charging characteristics for different charging controls are presented. A charging and discharging monitoring system was implemented based on a DSP. To improve the utilization of EV, it is necessary to design a charger with the function of fast charging and the capability of charging control, thus to prolong the battery life. The charging characteristics (charging time, charging current, temperature, switching frequency, and pulse period) of different charging methods (two-step, pulse, and Reflex) are analyzed and presented. Experiments were carried out based on the battery set of four 26 Ah lead-acid batteries in series. A LabVIEW-based monitoring system was constructed to record the voltage, current and temperature for the batteries. The DSP-based charging control combined with the monitor system features fast charging, digital and adjustable control.