Simulation study on hybrid ultracapactior-battery power system for PHEV

A hybrid power system composited by ultracapacitor and battery pack has been studied for battery packs only system is hard to meet the requirements of high specific power and energy reasonably. A Topology structure that the ultracapacitor system directly in series with DC/DC converter and then paralleled with battery pack were analyzed. The ultracapacitor, battery pack, DC/DC converter and hybrid power system were modeled based on this topology structure. The simulation results based on the Chinese urban driving cycle and the 10% of the regeneration efficiency shows that hybrid power system could meet the requirements of vehicle´s dynamic and reduce the consumption of power while the charging-discharging current of battery pack has been controlled in a reasonable limit which will be helpful to optimize the battery pack´s working performance to get a longer cycling life, high efficiency and high economy.