A Novel Dual-Motor Two-Speed Direct Drive Battery Electric Vehicle Drivetrain

Abstract

Although the demand of battery electric vehicle (BEV) growths fast as the requirement of reducing greenhouse gas emission and the usage of fossil fuels, the limited driving range and unfriendly retail price present barriers to BEV to provide comparable performance as a traditional vehicle. This paper proposes a dual-motor two-speed direct drive BEV powertrain to boost average motor operational efficiency in daily driving without increasing any complexity of manufacturing or control, ultimately, saving limited battery energy and manufacturing cost. The specifications of the proposed powertrain are first identified through mathematical and graphical calculations, which split traditional one propelling motor to two with separate permanent engaged gears to maximize the motor efficiency. Based on dynamic powertrain modeling in a Simulink/Simscape, economic shifting strategy, and dynamic torque transfer control are designed and tested. According to the simulation results, it is noticed that significant energy efficiency improvement can be achieved. Thanks to the optimized torque transfer control strategy, extremely low vehicle jerk are recorded during the shifting process. At last, conclusions can be made that the proposed dual-motor powertrain superior to the traditional single motor counterpart in terms of fuel economy, driving range, and cost.INDEX TERMS Dual motor, two speeds, electric vehicle, dynamic modeling, energy economy.

Stochastic Model Predictive Control for Dual-Motor Battery Electric Bus Based on Signed Markov Chain Monte Carlo Method

“…Step (1): For a typical driving cycle, the velocity variation is regarded as a time series corresponding to the Markov process. Round the fractional values v to finite discretized stages v k which are divided by p intervals ranging from minimum to the maximum velocity as shown in (1).…”

“…Here 70% of the driving cycle data is utilized for training, and 15% of the data is used to validate and test the network performance during and after the training process, respectively. Mathematically, the output value at k + 1 state can be represented as: ( 1) [ ( ), ( 1),... ( );…”

“…With the increasing concerns of environment protection and fossil fuel shortage problems, battery electric vehicles (BEVs) play a more and more prominent role, especially in the public transportation field. To further improve the comprehensive performance of BEVs, dual-motor coupling powertrain (DMCP) has been widely used recently, to coordinate the output power of two propulsion units to enhance the overall system efficiency and dynamic response [1]. Compared to the conventional single-motor architecture, simulation analysis under various typical driving cycles demonstrates that DMCP has a higher efficiency of electricity utilization [2] and can extend the BEV's driving range by 9% [3].…”

Non-independent speed control for dual-PMSM drives fed by a single three-leg VSI

“…Usually, the highest load motor will selected as the master motor, and the other one motor will be set as slave motor. For this topology, the operating conditions are restricted to same values such as same speed, same parameters and the same direction [1][2][3][4][5][6][7][8][9][10]. The only advantage of this technique is, only one set of sensor is required for the master motor and the slave motor will be not controlled.…”

Multi-Objective Optimal Gearshift Control for Multispeed Transmission Electric Vehicles

“…In some cases, the electric motor of an EV does not operate at optimal conditions, thereby increasing energy consumption. In addition, both speed and acceleration are difficult to improve, limiting the EV dynamic performance [6]- [8]. Moreover, if a motor without transmission is designed, to meet the efficiency and dynamic performance requirements, its volume may be large and its structure may be complex, thereby increasing costs.…”