Optimal Management and Comparison of SP-HEV vehicles using the dynamic programming method

This paper presents the application of optimal control to two series-parallel hybrid architectures. The dynamic programming method is applied to Toyota Hybrid System (THS) and a hybrid vehicle with Electric Variable Transmission (EVT). First the theoretical approach of dynamic programming and its application to SP-HEVs is presented. The way to take into account the extra degree of freedom, provided by the decoupling of wheel and engine, is presented. Then, the optimal fuel consumption of the two architectures is compared on different driving cycles for the case of a same reference vehicle Prius II. The over-consumption of the EVT topology is analysed and explained.