Modelling and active damping of powertrain oscillations for RWD electric vehicle

With the promotion and popularisation of electric vehicles, their driving performance has become an increasingly important issue. As there is no clutch in the powertrain to buffer and absorb the torsional vibrations, vehicle speed oscillations will be caused by various elastic components when the accelerator pedal is stepped or shifted by the driver suddenly. The sudden acceleration input will bring an unpleasant jerk to the vehicle body and accelerates the wear and tear of various parts in the powertrain. In this paper, considering the structure of full electric vehicle, a dynamic model of the powertrain is developed. An optimal feedback controller is proposed based on the state space equation of the vehicle to prevent the driveline from oscillating by actively controlling the motor output torque. The controller parameters are designed based on the optimal control theory. Simulation results demonstrate that the optimal control of motor output torque can reduce the wheel speed oscillations significantly

DESIGN AND DYNAMICS MODELING FOR ELECTRIC VEHICLE

This paper descript software for vehicle simulation and mathematical models that describe the motion of the vehicle. A dynamic simulation model of vehicle was developed using Matlab/Simulink and SimDriveline toolbox. The model has a configurable structure that is suitable to simu-lation with multiple levels. The powertrain system model developed using Simulink and SimDrivline could also be used as a generic, modular and fle-xible vehicle modeling platform to support the integration of powertrain design and control system optimization

Design of gearbox for electric vehicles

Táto diplomová práca sa zaoberá návrhom prevodovky pre elektromobil. Prevodovka má slúžiť ako pomyselná náhrada prevodovky elektromobilu VW ID.3. Navrhovaná prevodovka má dva rýchlostné stupne. V prvej časti práce je spracovaná rozsiahla rešerš hnacieho a prevodového ústrojenstva batériových elektromobilov. Ďalšia časť zahŕňa výber koncepcie prevodovky a následne rozoberá riešenie konkrétnych konštrukčných uzlov – ozubené súkolesia, pásové brzdy (radiace komponenty jednotlivých stupňov), unášače, hriadeľ, ložiská. V závere diplomovej práce je navrhnutá dvojrýchlostná planétová prevodovka zhodnotená.This diploma thesis deals with designing electric vehicle gearbox. Gearbox should serve as virtual replacement for actual transmission of VW ID.3 EV. Designed gearbox has two gears. In the first section there is an extensive search processed of drivetrain and transmission of battery electric vehicles. Next section contains choice of transmission concept and analyses solving of individual structural nodes – gear wheels, band breaks (components that engage individual gears), carriers, shaft, bearing. In the conclusion of diploma thesis, the two-gear planetary transmission is evaluated.

Design of systems and components for high-speed electric propulsion systems

This PhD dissertation presents the modelling and design of a novel High Speed (HS) Electric Propulsion System (EPS) for automotive application. In particular, Chapter I presents a comparison among different EPS configurations, which are designed by combining different Permanent Magnet Synchronous Machines (PMSMs) with the corresponding most suitable transmission system; this is done in order to investigate the competitiveness of HS-EPS for automotive applications. Subsequently, the design of a novel ferrite-based HS-PMSM suitable for automotive application is presented in Chapter II. The design has been carried out through a novel multi-parameter analytical design procedure, which has been developed with the aim of achieving a preliminary machine design that considers both design targets and constraints. This preliminary design has been then validated through accurate and extensive finite element analyses, which regard both mechanical and electromagnetic performances. In order to guarantee appropriate coupling between the designed HS-PMSM and vehicle wheels, the design and optimization of a novel coaxial Magnetic Gear Transmission (MaGT) is presented in Chapter III. In particular, a single-stage MaGT is designed at first in accordance with mechanical and magnetic analytical models. However, as far as a very high gear ratio is required (more than 20), the design of a double-stage MaGT has been carried out, which addresses some of the issues arising from the single-stage solution. A comparison in terms of performances and sizes between the two designed MaGTs is thus presented and discussed: the results obtained through the analytical models are validated by means of accurate finite element analyses. Subsequently, a further optimization of the double-stage MaGT has been carried out, which aims at reducing the harmonic content of the magnetic flux density. A comparative study between the two double stage MaGTs is presented and discussed, especially with reference to core losses and temperature distribution, highlighting the improved performances achieved by the optimized configuration

Energy and Service Life Management Strategy for a Two-Drive Multi-Speed Electric Vehicle

Regulations of zero emission passenger cars appear on the horizon, and battery electric vehicles (BEV) are the main solution from the current market. It has been a focus of both academia and industry to extend their range. One of the main approaches is to reduce their energy consumption. Recent studies have shown that the two-drive topology and the multi-speed topology help to do so. It is natural to combine both concepts and to design a two-drive multi-speed topology for BEVs. Due to its more than one degree of freedom, an online energy management strategy (EMS) controlling torque set points of both electric motors and target gear positions is necessary to exploit its potential for reducing total energy consumption in real-world applications. There are numerous studies on EMSs for BEVs and hybrid electric vehicles. The overwhelming majority of them shared the same assumption: shift processes are neglectable. Based on the shift duration statistics, the shift processes of the most common transmissions in today’s market are too long to be ignored for an EMS with an operation frequency of at least 1 Hz. How to develop an EMS that considers shift processes? Suppose that an EMS is developed. It controls the powertrain in favour of low energy consumption, and the parts and the components are loaded accordingly. Some parts might fatigue and fail much faster than others, not because of poor construction dimensioning, but because of excessive use. What can an EMS do to prevent such an extreme scenario? Furthermore, is there a general way to design EMSs for multi-drive BEVs? This thesis is initiated by developing an online EMS for a two-drive multi-speed BEV called “Speed4E”, and tends to address the questions raised earlier. A predictive EMS in a Model Predictive Control framework is developed. A hybrid system considering the shift processes is proposed. Based on it and the Hybrid Minimum Principle, a solver and its algorithms are developed. The Principle is chosen for its accuracy and low time complexity, the two most important attributes of an online EMS. Minimizing the instantaneous Hamiltonian in the Principle is mathematically analysed. Several Lemmas that reduce the time complexity considerably are produced. Compared to an EMS that minimizes instantaneous energy consumption and ignores shift processes, the predictive EMS reduces the energy consumption in the Worldwide Harmonized Light Vehicles Test Cycle (WLTC) by 0.26 % and the shift count by 63.41 %. The hybrid system, the predictive EMS and the mathematical analysis are, as far as the author knows, first of their kinds. A novel multi-criteria operation strategy (MCOS) considering powertrain service life is proposed. Thanks to the hybrid system, the influence of the shift processes on fatigue is included. The MCOS extends the powertrain service life by several times but sacrifices the energy consumption. A general multi-drive (at least two) multi-speed electric powertrain is proposed. Its hybrid system is formulated. The Principle is applied to produce the optimality condition. It is showcased, how to modify certain sets and sample space in the formulation to have the general model and problem represent certain electric powertrains. A unified framework to design EMS for the general multi-drive electric powertrain is proposed, where the algorithms developed for the predictive EMS can be applied