HYBRID AND ELECTRIC POWERTRAINS
To support the gathering momentum in the electrification of the transport sector, IFPEN is working on the various building blocks of the powertrain:
- electric machines,
- their power electronics: inverters and control,
Lost energy recovery and the development of electricity generators are also the focus of research developments since they contribute to the improvement in the energy efficiency of powertrains.
Electric machines for propulsion
Electric vehicles are a favored solution to reduce road transport CO2 emissions. IFPEN has been working on the design of high-efficiency powertrains and opted to use synchronous reluctance motor technology, which has a triple advantage:
- it uses fewer magnets, and hence rare earths, than the permanent magnet synchronous motor,
- its production cost is therefore lower,
- it is highly efficient compared to motors currently marketed.
Conversely, however, engine torque management requires a more complex engine control solution. A version adapted to vehicles requiring low voltages was marketed in 2017 with Aixam. Research efforts are continuing on a higher voltage motor for B-segment cars.
A synchronous reluctance motor application for low power applications
IFPEN and Italian SME Mavel have developed a highly efficient permanent magnet synchronous reluctance motor for low-power vehicles. Today, it is used in the e-Aixam no-license electric vehicle range, launched by Aixam in 2017.
« We decided to develop synchronous reluctance electric powertrain technology with our partner Mavel to meet two objectives:
- make better use of the energy stored in the battery, which involved:
- optimizing powertrain efficiency,
- and hence minimizing losses in terms of the power electronics and the machine itself,
- making prudent industrial decisions concerning production costs and supplies. The permanent magnet synchronous reluctance motor incorporates fewer magnets compared to a synchronous motor, magnets being made up of materials that are both rare and expensive.
The first market launch resulting from this joint research concerns the e-Aixam vehicle range, the machines for which are produced in Italy by Mavel edt, our joint subsidiary with Mavel. These machines develop a power of around 10 kW with 77 volts.
With the same technology, we can offer an expanded range in terms of power (up to 150 kW at a higher voltage), to address the needs of a rapidly-developing electric vehicle market, including the Chinese market. »
HivoB: a new electric machine for B-segment vehicles
After a first application in small, no-license vehicles, IFPEN is now targeting applications requiring more power.
« We’ve turned our attention to segment B, since it is the biggest growth segment in the electric vehicle market. This segment includes cars like the Renault Zoe, BMW i3 and the Citroën C3, which require power of around 120 kW. Synchronous reluctance technology offers the best cost/performance/efficiency compromise: that is why we chose it. However, it demands advanced electronic control and more complex engine torque management to compensate for the small number of magnets: hence we have developed the appropriate control laws. We have also introduced innovations with respect to the active parts of the machine and the mechanical integration of the system with:
- an inverter integrated directly in the motor, leading to a significant cost reduction,
- optimized engine temperature management,
- and improved efficiency.
In parallel, we are working on a smaller motor used with a lower voltage battery (48 volt machines), this time intended for hybrid vehicles. Ultimately, our aim is to develop a range of motors covering the needs of all market segments.»
Misa Milosavljevic, Electric Powertrains project manager, IFPEN
With more than ten years’ experience in the research, characterization and modeling of electrochemical storage systems (ESS) for transport, IFPEN is today recognized as a leading player in battery modeling and simulation in France. Its research now covers stationary applications.
« Battery modeling is central to our research in the field of ESS. Our models are constantly being improved and are capable of representing:
- the electrothermal behavior of ESS,
- their aging,
- even abuse mechanisms, thanks to the accurate modeling of the thermal runaway phenomenon for Li-ion batteries.
Thanks to active intelligence gathering and our involvement in networks such as RS2E in France, we keep our models up to date for the most recent commercial battery and prototype technologies.
Battery modeling requires:
- the implementation of mathematical approaches that can be simple (empirical by electrical analogy) or highly complex (physical models, ab initio methods) depending on the needs of the end user,
- access to test facilities and related tools (mathematical processing, data management, sensitivity analyses, etc.) enabling the effective calibration of parameters associated with the models, and their validation. Since aging tests to calibrate durability models are particularly costly in terms of time and resources, we are a partner in the COMUTES² consortium, set up to organize pooled test campaigns open to all.
Our models are:
- available in the Electric Storage library of the Simcenter Amesim system simulation platform marketed by Siemens Digital Industries Software,
- used and improved:
- for research we conduct as part of our industrial support activities: choice of technology, dimensioning for an application,
- in collaborative projects to speed up the development of the electric sector, such as the European Demobase project,
- to innovate in areas of current interest such as rapid recharging, the second life of batteries, new generations of solid-state batteries, etc. ».
Julien Bernard, Battery project manager, IFPEN
Electric machine management
« The development of new high-efficiency, low-cost electric powertrains for hybrid and electric vehicles requires onboard electronic systems incorporating increasingly complex control algorithms. With these, it is possible to exploit the potential of new-generation electric machines designed by IFPEN and its industrial partners.
Today, our expertise enables us to propose command strategies to optimize the management of electric machines. To speed up the electric machine control development process, we came up with an onboard code integration methodology via a chain of tools: development of algorithms / simulation tests / automatic code generation and validation on a control test bench, with the acquisition at very high frequency of control variables. This integrated methodology has already been successfully tested by one of our industrial partners.»
Gianluca Zito, Electric Powertrains project manager, IFPEN
Electrification of the air loop
An electric turbocharger for future IC powertrains
To further improve performances and reduce vehicle consumption, IFPEN is developing an original solution based on an electric turbocharger, which could be used in future powertrains, particularly hybrid ones. A demonstrator has even operated at up to 190,000 rpm!
« There are two main advantages with an electric turbocharger:
- increased engine performance – particularly dynamic –, thereby offering improved drivability,
- power taken from the turbocharger:
- thereby reducing fuel consumption and CO2 emissions,
- or increasing electric range.
Thanks to a development focusing on the entire electric system (motor/generator and inverter), we are able to propose an original and innovative electric turbocharger solution operating at up to 190,000 rpm and developing more than 4 kW with 48V.
While this technology is initially aimed at top-of-the-range private vehicles, it is also likely to be used in hybrid 48V solutions that will be developed over the next few years. It is also aimed at other transport sector applications, particularly goods transport and construction site machinery. »
Fabrice Le Berr, head of the Electric Systems Department, IFPEN
The ORC turbine
- Stationary energy recovery
IFPEN and Enogia, a French SME specializing in ORC (Organic Rankine Cycle) thermal recovery systems, are currently working on a system aimed at recovering the heat lost by large stationary installations (2 MWth) and converting it into electricity.
Pascal Smague, an IFPEN researcher, presents the demonstrator tested on the IFPEN-Lyon site (in French)
- Engine heat recovery
IFPEN and Marseille-based SME Enogia have also developed a low-power “vehicle” version of these ORC systems, adapting the technology for the transport market.
« ORC systems make it possible to recover the heat lost and convert it into mechanical or electrical energy. These systems have been used for many years for stationary applications and our aim is to adapt them to the transport sector, particularly heavy trucks and light vehicles. The energy produced will be used to support the vehicle’s engine, thereby reducing its fuel consumption and CO2 emissions. We are targeting reductions of between 2 and 3% in standard operating conditions. The original aspect of our approach is that, rather than being recovered from the exhaust gases, it is recovered from the engine’s cooling system, where the temperature is lower. This will make it possible to make the system lighter, more compact, cheaper, more reliable and easier to integrate. »
Pierre Leduc, expert, IFPEN
See video (in French) : how do ORC turbines operate for engines?
« To begin with, we focused on stationary applications, primarily in the field of renewable energies and energy efficiency. Within the framework of our partnership with IFPEN, we are expanding our perimeter to the transport sector, particularly via miniaturization. Our heat recovery approaches are complementary and IFPEN’s testing facilities will help us bring our products to market more quickly. We already have several projects on the table for the car, road transport and maritime sectors. Meanwhile, we continue to work on stationary applications, with the development of a 100 kW electric machine (currently in the process of being finalized), to meet power needs higher than those covered by our current product range. »
Arthur Leroux, Chairman, Enogia
- A microturbine for onboard electricity management
Less noisy, reduced vibrations, less polluting: the microturbine appears to be an optimal solution for generating electricity onboard a vehicle. IFPEN is examining the concept closely.
« A microturbine is an electric generator with a turbine that rotates at high speeds and can provide up to 100 kWe of power. We have opted to focus on powers below 30 kWe for the following applications:
- pleasure boats,
- refrigerated trucks,
- stationary applications, such as relay antennae,
- cogeneration installations,
- or, why not, private vehicles to extend their range.
Compared to a piston engine delivering the same power, our microturbine will:
- be quieter,
- be more compact,
- vibrate less and emit fewer pollutants, thanks, in particular, to a combustion chamber designed entirely by IFPEN,
- and also make it possible to conduct maintenance operations less frequently due to its greater reliability.
We have been operating a demonstrator since the fall of 2018, designed to help us target the components requiring adjustments. We are planning a second demonstration, followed by tests in representative conditions: our product could be mature by 2020. »
Misa Milosavljevic, Microturbine project manager, IFPEN
Battery simulation tool
- the pre-dimensioning of the battery pack thanks to a tool that enables a few macroscopic data to be used to generate a first Li-ion battery design and its associated model,
- and the evaluation of complex phenomena, such as aging or thermal runaway. »
Grégory Font, Powertrain system modeling project manager IFPEN