Design optimization of the transmission system for electric vehicles considering the dynamic efficiency of the regenerative brake

Bolin Zhao, Chen Lv, Theo Hofman, Maarten Steinbuch, Junzhi Zhang, Dongpu Cao

Research output: Contribution to journalConference articleAcademicpeer-review

Abstract

In this paper, gear ratios of a two-speed transmission system are optimized for an electric passenger car. Quasi static system models, including the vehicle model, the motor, the battery, the transmission system, and drive cycles are established in MATLAB/Simulink at first. Specifically, since the regenerative braking capability of the motor is affected by the SoC of battery and motors torque limitation in real time, the dynamical variation of the regenerative brake efficiency is considered in this study. To obtain the optimal gear ratios, iterations are carried out through Nelder-Mead algorithm under constraints in MATLAB/Simulink. During the optimization process, the motor efficiency is observed along with the drive cycle, and the gear shift strategy is determined based on the vehicle velocity and acceleration demand. Simulation results show that the electric motor works in a relative high efficiency range during the whole drive cycle. The energy economy of the case-study vehicle with the optimized a two-speed transmission is also compared to that of the baseline vehicle with fixed-ratio reduction gear.

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Electric vehicles
Brakes
Gears
MATLAB
Regenerative braking
Torque motors
Electric motors
Passenger cars
Design optimization

Cite this

@article{b0d47eae6f1d42f5bb566c3d3e157ba6,
title = "Design optimization of the transmission system for electric vehicles considering the dynamic efficiency of the regenerative brake",
abstract = "In this paper, gear ratios of a two-speed transmission system are optimized for an electric passenger car. Quasi static system models, including the vehicle model, the motor, the battery, the transmission system, and drive cycles are established in MATLAB/Simulink at first. Specifically, since the regenerative braking capability of the motor is affected by the SoC of battery and motors torque limitation in real time, the dynamical variation of the regenerative brake efficiency is considered in this study. To obtain the optimal gear ratios, iterations are carried out through Nelder-Mead algorithm under constraints in MATLAB/Simulink. During the optimization process, the motor efficiency is observed along with the drive cycle, and the gear shift strategy is determined based on the vehicle velocity and acceleration demand. Simulation results show that the electric motor works in a relative high efficiency range during the whole drive cycle. The energy economy of the case-study vehicle with the optimized a two-speed transmission is also compared to that of the baseline vehicle with fixed-ratio reduction gear.",
author = "Bolin Zhao and Chen Lv and Theo Hofman and Maarten Steinbuch and Junzhi Zhang and Dongpu Cao",
year = "2018",
month = "1",
day = "1",
doi = "10.4271/2018-01-0819",
language = "English",
volume = "2018",
journal = "SAE Technical Papers",
issn = "0148-7191",
publisher = "Society of Automotive Engineers (SAE)",

}

Design optimization of the transmission system for electric vehicles considering the dynamic efficiency of the regenerative brake. / Zhao, Bolin; Lv, Chen; Hofman, Theo; Steinbuch, Maarten; Zhang, Junzhi; Cao, Dongpu.

In: SAE Technical Papers, Vol. 2018, 2018-01-0819, 01.01.2018.

Research output: Contribution to journalConference articleAcademicpeer-review

TY - JOUR

T1 - Design optimization of the transmission system for electric vehicles considering the dynamic efficiency of the regenerative brake

AU - Zhao,Bolin

AU - Lv,Chen

AU - Hofman,Theo

AU - Steinbuch,Maarten

AU - Zhang,Junzhi

AU - Cao,Dongpu

PY - 2018/1/1

Y1 - 2018/1/1

N2 - In this paper, gear ratios of a two-speed transmission system are optimized for an electric passenger car. Quasi static system models, including the vehicle model, the motor, the battery, the transmission system, and drive cycles are established in MATLAB/Simulink at first. Specifically, since the regenerative braking capability of the motor is affected by the SoC of battery and motors torque limitation in real time, the dynamical variation of the regenerative brake efficiency is considered in this study. To obtain the optimal gear ratios, iterations are carried out through Nelder-Mead algorithm under constraints in MATLAB/Simulink. During the optimization process, the motor efficiency is observed along with the drive cycle, and the gear shift strategy is determined based on the vehicle velocity and acceleration demand. Simulation results show that the electric motor works in a relative high efficiency range during the whole drive cycle. The energy economy of the case-study vehicle with the optimized a two-speed transmission is also compared to that of the baseline vehicle with fixed-ratio reduction gear.

AB - In this paper, gear ratios of a two-speed transmission system are optimized for an electric passenger car. Quasi static system models, including the vehicle model, the motor, the battery, the transmission system, and drive cycles are established in MATLAB/Simulink at first. Specifically, since the regenerative braking capability of the motor is affected by the SoC of battery and motors torque limitation in real time, the dynamical variation of the regenerative brake efficiency is considered in this study. To obtain the optimal gear ratios, iterations are carried out through Nelder-Mead algorithm under constraints in MATLAB/Simulink. During the optimization process, the motor efficiency is observed along with the drive cycle, and the gear shift strategy is determined based on the vehicle velocity and acceleration demand. Simulation results show that the electric motor works in a relative high efficiency range during the whole drive cycle. The energy economy of the case-study vehicle with the optimized a two-speed transmission is also compared to that of the baseline vehicle with fixed-ratio reduction gear.

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