| OPTIMAL CONTROL FOR SHIFTING COMMAND OF TWO-SPEED
ELECTRIC VEHICLES CONSIDERING SHIFTING LOSS |
| Liyue Yang 1, Dohyun Park 1, Shaowen Lyu 1, Chunhua Zheng 2, Namwook Kim 1 |
1Department of Mechanical Engineering, BK21 FOUR ERICA-ACE Center, Hanyang University
2Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences |
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| ABSTRACT |
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The energy efficiency of battery electric vehicles (BEVs) remains to be improved, and a two-speed transmission
can be regarded as a prominent technology for BEVs because the two-speed transmission can improve acceleration and
powertrain efficiency. However, the transmission device requires a well-designed control strategy because the performance of
the vehicle can deteriorate if the controller selects an inefficient gear step. Herein, a gear shifting control concept based on
dynamic programming is proposed to maximize the system efficiency, where the shifting loss caused by shifting actuators is
considered in the control problem. The performance of the proposed control concept is compared to that of a controller utilizing
a shifting map obtained via quasi-static optimization. It is shown that the proposed concept improves the efficiency by 0.01 ~
0.4 % compared with the shifting map applied to different hysteresis gaps, and around 13 % shifting frequency reduction has
been experienced while the best energy hysteresis gap is selected. In addition to improving efficiency, the control concept can
be extremely beneficial to engineers who wish to design the best control strategy without calibrating the control parameters
when the actuator loss is considered in the control problem. |
| Key Words:
Electric vehicles, Two speed transmission, Shifting command control, Dynamic programming, Energy
consumption, Shifting frequency |
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Corresponding Author.
Namwook Kim , Email. 
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