Title: Optimal torque distribution strategy for dual traction motors in a series hybrid electric intra-city bus

Authors: Minjae Kim; Daebong Jung; Kyoungdoug Min

Addresses: Department of Mechanical Engineering, Myongji University, Building 1, Room 212, 116, Myongji-ro, Cheoin-gu, Yongin-si, Gyeonggi-do, South Korea ' Seoul School of Mechanical and Aerospace Engineering, Seoul National University, Building 314, Room 205, 1 Gwanak-ro, Gwanak-gu, Seoul, South Korea ' School of Mechanical and Aerospace Engineering, Seoul National University, Building 301, Room 1209, 1 Gwanak-ro, Gwanak-gu, Seoul, South Korea

Abstract: In hybrid vehicles, the focus in optimisation methodologies to improve the fuel economy has generally been on the energy flows between the engine motor and battery, but the energy distributions in the traction motor unit have received little attention. Thus, the energy flow from the engine/generator unit to the traction motors that is determined by optimal control strategies may not be transferred to the wheels in the most efficient manner. To address such problems, this research studies an optimal torque distribution for the traction motors where an optimal torque distribution map is used that contains information for the most efficient distribution at all operating points. The optimal power distribution, apart from the energy flow from the engine to the traction motor unit, could be achieved for all operating regions with realistic bus speed profiles. As a result, the favourable type for the proposed strategy could be defined. The proposed strategy was demonstrated through simulations using AMEsim and Simulink co-simulation.

Keywords: series hybrid electric vehicles; optimal torque distribution; dual traction motors; permanent magnet motors; heavy vehicles; optimisation; electric buses; city buses; energy flow; optimal control; simulation.

DOI: 10.1504/IJHVS.2017.080935

International Journal of Heavy Vehicle Systems, 2017 Vol.24 No.1, pp.18 - 44

Available online: 08 Dec 2016 *

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