Title: Stochastic dynamic programming for the energy management of a serial hybrid electric bus

Authors: Philipp Elbert; Martin Widmer; Hans-Jörg Gisler; Christopher Onder

Addresses: Institute for Dynamic Systems and Control, Department of Mechanical and Process Engineering, ETH Zürich, 8092 Zürich, Switzerland ' Carrosserie Hess AG, 4512 Bellach, Solothurn, Switzerland ' Carrosserie Hess AG, 4512 Bellach, Solothurn, Switzerland ' Institute for Dynamic Systems and Control, Department of Mechanical and Process Engineering, ETH Zürich, 8092 Zürich, Switzerland

Abstract: Hybrid electric vehicles require an energy management strategy to determine how the requested power is to be split up between the combustion engine and the electric energy buffer. The energy management significantly influences the overall efficiency of the vehicle. A careful design and implementation is thus crucial to achieve good fuel economy. This paper proposes a strategy based on stochastic dynamic programming with the following advantages: First, optimal performance is guaranteed with respect to the available information. Second, the resulting controller is a look-up table and the computational burden of its evaluation is very light. Third, controller synthesis is a systematic procedure allowing to trade off multiple objectives, e.g., fuel economy and drivability. Simulation results show 3-5% close to global optimal performance. During practice, a hybrid bus with the proposed energy management yields a fuel consumption reduction of 22-29% compared to a Diesel bus with comparable specifications.

Keywords: hybrid electric vehicles; HEVs; hybrid vehicles; energy management; stochastic dynamic programming; public transport; electric double layer capacitors; fuel economy; drivability; simulation; serial hybrid electric buses.

DOI: 10.1504/IJVD.2015.073115

International Journal of Vehicle Design, 2015 Vol.69 No.1/2/3/4, pp.88 - 112

Received: 30 Sep 2014
Accepted: 03 Feb 2015
Published online: 20 Nov 2015 *

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