Optimization of Power Management in an Hybrid Electric Vehicle Using Dynamic Programming

PEREZ L.V.; BOSSIO G.R.; MOITRE D.; GARCÍA G.O.

Tegucigalpa

Congreso; V Pan American Workshop on Applied and Computational Mathematics; 2004

Computational Science Research Center- San Diego State University y Univ. Nac. Autón. de Honduras

Hybrid electric vehicles are those powered from two different sources. Typically they are equipped with an internal combustion engine, and also with an electrical storage system, such as a bank of batteries or ultra-capacitors. While braking, these vehicles may convert kinetic energy to electrical energy and send it back to the electrical storage system (regenerative braking). The whole vehicle system may be abstracted to one consisting of two energy sources, one of them rechargeable and the other consumable, and an energy consumer that feed or receive energy from the sources. A centralized control strategy is required to define the instantaneous power flows among these three main components. In this work we derive the power split between the two sources such that fuel consumption is minimized while the vehicle performs a given velocity cycle. Bounds on the power flows from both sources are considered. There is also a constraint of an integral nature that arises from the fact that the energy of the electrical storage system must remain between proper limits, in order to avoid physical damage. The problem is posed as a finite horizon dynamical optimization problem with constraints and is solved by a dynamic programming (DP) approach. The hybrid electrical vehicle being developed in the University of Río Cuarto, Argentina is taken as the case study.