It is a widespread political will in many countries to reduce vehicles with combustion engines and to substitute them with electrical drives. At the same time, experts the share of electric vehicles sold on all vehicles to increase from 1% in 2015 to 54% in 2040.
Integrated modular distributed drivetrain for Electric & Hybrid Vehicles
This has triggered a surge in research and development to search for technical solutions for even better drive systems suitable for everyday use.
DRIVEMODE aims to develop a distributed and integrated drivetrain module (IDM) that will fit in all types of mass-produced electric and hybrid cars, from light and C & D passenger vehicles to high performance and light-duty vehicles.
The DRIVEMODE concept stems from the idea of integrating technologies (used in electrical machines and in power electronics) to provide highly efficient and compact integrated modular drivetrain components dedicated to different kinds of cars. These include mass-produced electric and hybrid vehicles, low performance and high-performance vehicles and different types of heavy-duty vehicles.
The economic feasibility of mass-manufacturing of different electric machine topologies is studied to choose the best trade-off between performance, manufacturing cost and efficiency in the selected performance range.
The main components of DRIVEMODE are:
Publication of the results and project funding by the European Commission
In 2019, Drivemode chose Coiltech's World Magnetic Conference to present the results of its activities.
These dissemination sessions are a prerequisite for the project funding by the European Commission (Horizon 2020, programme GV04, grant no. 769989).
DRIVEMODE is managed by the VTT Technical Research Centre of Finland and consists of a group of 12 partners from 6 different EU member states:
Semikron Elektronik GmbH & Co. KG, AVL Trimerics GmbH and Technische Universitaet Ilmenau (Germany), Visedo Oy (Finland), Chalmers Tekniska Hoegskola AB, National Electric Vehicle Sweden AB and Borgwarner Sweden AB (Sweden), Thien Edrives BMGH (Austria), Univerza V Ljublkani (Slovenia) and, S.C.I.R.E. Consorzio and Fondazione iCons (Italy).
The following companies and institutions have joined forces to develop traction technologies beyond the current state of the art, with a strong focus on industrial feasibility for mass production, aiming at lower costs with higher specific torque and power density.
High-efficiency SIC converter
The DRIVEMODE drivetrain concept study requires the converter to deliver up to 140 A of continuous AC current at a challenging power semiconductor switching frequency of 20kHz. To achieve this goal and save expensive SiC MOSFET chip area, a detailed FEM simulation study was performed.
The aim of the different optimization steps was to improve the thermal performance of the converter resulting in a higher output current. In particular, a slightly increased chip distance has proven to significantly reduce the overall temperature and the temperature difference of chips.
In order to select the optimal chip spacing, various test structures have been analyzed, the thermal influence of the chip spacing was investigated and optimized for the requirements of the inverter. In addition, alternative materials for use as a heat sink and thermal paste were investigated. To support excellent thermal performance a SiN ceramic substrate is used for electrical isolation of heat sink and power electronics.
Finally, design variations of the heat sink with an early design of the power hybrids are investigated and optimized in terms of thermal performance and coolant flow dynamics.
The converter concept chosen for the DRIVEMODE demonstrator is based on only 3 parallel SiC MOSFET (1200V) per phase allowing for an output power of 116 kW at a power factor of 0,85 and a battery voltage of 800V.
The 35kW/l power density of this full SiC inverter demonstrates an increase by 400% compared to a standard Si power electronics-based inverter. A design for manufacturing approach helps to reduce the cost further and improve device reliability.
Developed e-motor technologies: permanent magnet synchronous and induction machine
Within the DRIVEMODE project, two electrical motor technologies were evaluated in detail: Permanent magnet synchronous machine (PMSM) and squirrel cage asynchronous induction machine (IM).
Both technologies are mature and start of production-ready for series production by the year 2020. Permanent magnet motor has been accepted as the main traction machine concept because of its smaller dimensions and better efficiency.
The further expected optimization is mainly in the reduction of rare earth magnets volume and overall mass (reduction in used material) while keeping the performance at the same level and improving the overall efficiency of the proposed design.
Other further development will include a focus on, improved over-load, increase of overall efficiency, increase of efficiency in working points, torque ripple reduction by definition of proper skew angle (number of segments), detailed thermal modelling and cooling system improvement.
The calculated PMSM torque density (including the weight of active parts) is 4.9 Nm/kg, power density is 3.5 kW/kg and power versus used permanent magnet weight is 98 kW/kg with an efficiency of more than 96%.
All data are calculated applying electric current limitation to 140 Aeff at 720 VDC. The overall drive train (gearbox, PMSM and power inverter) will be also analysed in terms of noise and vibrations
To speed up a transmission gearbox to 20,000 revolutions per minute in a controlled manner is an engineering challenge of its own kind, with complexities like noise, vibrations, frictional power losses, and not the least power losses caused by the viscosity of the lubricating oil.
The DRIVEMODE transmission has been designed to operate under elasto-hydrodynamic lubrication, or with thin, semi-solid oil films separating the metal surfaces from each other.
By using a lubricating oil of low viscosity and EP additives, combined with a controlled supply of oil, the lubrication conditions in all gear contacts have been assured at the same time as the viscous power losses at the highspeed end have been minimised.
The low viscosity leads to exceptionally thin oil films, which sets high requirements on the surface quality of the gear surfaces.
Laboratory experiments are currently being carried out in support of selecting the surface finish and possibly coatings for the gears.
AVL Trimerics GmbH
AVL is the world’s largest independent company for the development, simulation and testing technology of powertrains (hybrid, combustion engines, transmission, electric drive, batteries and software) for passenger cars, trucks and large engines.
BorgWarner Sweden AB
BorgWarner is a global product leader in clean and efficient technology solutions for combustion, hybrid and electric vehicles. With manufacturing and technical facilities in 62 locations in 17 countries, the company employs approximately 27,000 worldwide
CHALMERS TEKNISKA HOEGSKOLA AB
Chalmers develops leading research in the areas of life sciences, materials science, information technology, micro-and nanotechnology, environmental sciences and energy technology. As a university of technology and science, Chalmers mission is to produce and spread knowledge, expertise and solutions that benefit everyone: both individuals and society.
Danfoss Mobile Electrification specializes in hybrid and electric powertrain systems for off-highway and marine markets. A business division of Danfoss, it develops and manufactures high-performance power systems for heavy-duty vehicles, machines and marine vessels, based on its unique synchronous reluctance assisted permanent magnet (SRPM) technology.
Fondazione ICONS is a private non-profit organisation, whose mission is to improve human capital through public communication and exploitation of European research and innovation for the benefit of society. iCube is the innovative communication and exploitation programme of Fondazione ICONS designed for researchers and innovators aiming to maximize their research impacts on society, engaging citizens, scientists, investors, policy makers and the media.
NATIONAL ELECTRIC VEHICLE SWEDEN AB
NEVS’ vision is to shape mobility for a more sustainable future. Core to this is a global portfolio of fully electric premium cars, mobility solutions and sustainable city offerings. NEVS is the first joint venture company with investors from outside China that is granted a New Energy Passenger Vehicle Project investment approval by NDRC.
The Consortium SCIRE was founded in 2001 by “Tor Vergata” University of Rome and “Elasis” research centre (FIAT group). It collaborates with research centres and several companies, encouraging cooperation and technology transfer. Its main activities are focused on four areas: Transport (in particular green vehicles), Energy Efficiency, Innovative Materials and Business Excellence.
SEMIKRON Elektronik GmbH & Co KG
SEMIKRON addresses the main requirements of the power electronics market – reliability, compactness and performance – by continuously implementing innovations. Their products are designed for applications in the markets of the future, such as wind and solar, energy-efficient industrial drives and e-mobility by covering a power range from a few KW to several Megawatt. In this project, SEMIKRON will accelerate these activities to develop a highly integrated electrical drivetrain.
Technische Universität Ilmenau
TU Ilmenau is famous for its long tradition of training students to become mechanical or electrical engineer. Today the university’s profile contains technology, natural science, economics and media. Over the last years, six research clusters have been established: nanoengineering; digital media technology; mobile communication; precision technology and precision measurement technology; technical and biomedical assistance systems; propulsion, energy and environmental systems engineering.
THIEN eDrives GmbH
THIEN eDrives is a well- recognized specialist in the electric drive system and has a range of services that start with consulting concerning electric drive systems and can end with serial production. THIEN’s product range includes drive systems, inverters and motors.
VTT – Technical Research Centre of Finland
Tecnomatic produces flat wire winding stator for the induction machines, collaborating actively in the design.
University of Ljubljana
The Faculty of Electrical Engineering is a highly reputed institution, as its teaching and scientific research work focuses on technologies of the future in various fields of electrical engineering. In parallel with its leading role in educating top experts, the Faculty is leading and/or co-partnering numerous national and international research projects.
- Drivemode Website: http://drivemode-h2020.eu/project/
- Next-Generation Electric Drivetrains for Fully Electric Vehicles (final Online Event of Drivemode, ModulED, ReFreeDrive)
ReFreeDrive - https://www.youtube.com/watch?v=hqq8e9EVrbs&t=5s
Drivemode - https://www.youtube.com/watch?v=PqOOi6fHDcc
ModulED - https://www.youtube.com/watch?v=MZuyrwpkwoA
- Resources: http://drivemode-h2020.eu/resources/