Optimal Power Distribution Strategy for Series-Parallel Hybrid Electric Vehicles

The series-parallel hybrid electric vehicle, which employs a planetary gear set to combine one internal combustion engine and two electric motors, can take advantages of both series and parallel hybrid system by controlling power flows. In this system, the control of power flows means adjusting not only the amount and direction of mechanical and electrical power but also the operating point of the engine. This study introduces the power distribution strategy which uses control maps to minimize the loss in power flow and operate engine on efficient point. And the control maps can be obtained by optimization process seeking efficient operating point for the given speed, load and battery charge/discharge power. The suggested strategy distributes the power flows efficiently and further, it helps to build energy control strategy since battery power can be controlled easily.