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Rare Earth Free e-Drives featuring low cost manufacturing

Periodic Reporting for period 1 - ReFreeDrive (Rare Earth Free e-Drives featuring low cost manufacturing)

Reporting period: 2017-10-01 to 2019-03-31

The ReFreeDrive project is focused on contributing to avoid the use of rare earth magnets through the development of a next generation of electric drivetrains, ensuring the industrial feasibility for mass production while focusing on the low cost of the manufacturing technologies.
The project intends to study and develop simultaneously two solutions for the power traction system of electrical vehicles.
Both solutions are brushless AC electrical machines: induction machine with fabricated and copper die‐cast rotor (IM) and synchronous reluctance (SynRel) machine.
Through their configurations these machines not only are rare‐earth magnet free, but also share common features that can be exploited during the design step, as well in the manufacturing process.
These common features lead to a complex synergy between the two technologies, which justify the development of different topologies of electric machines in just one project.

ReFreeDrive motor topologies have good room for cost reduction by off-setting permanent magnet use. One of the key avenues for cost reduction is the reduction of size through different techniques (outer rotor, higher rotational speed, compact winding…).
An optimized use of copper on the project provides technical design with a higher efficiency due to lower losses regards other alternatives, and more efficient heat management.

Beyond the motor design, ReFreeDrive also consider an integrated design of the power train that allows the optimization of the electric connections, the cooling systems and the housing.
• WP1 Management has overseen the work flow, organizing meetings and web conferences when needed and working with the Work Package Leaders (WPLs) to ensure activities are carried out according to schedule. A quality management procedure has been set in place and followed for the deliverables sent during this period. Project milestones have been reviewed, achieving the first of them (related to the boundary conditions definition).

• WP2 has established the boundary conditions at different levels, defining the driving cycles, and setting the basis for the design work packages (WP3, WP4) and the integration work package (WP5) to work with.

• WP3 and WP4 have optimized the designs of their respective technologies, induction machines (IM, WP3) and synchronous reluctance machines (SynRel, WP4) with respect to the preliminary analysis shown in D1.1 (M9). Different motor configurations have been studied for each technology from an electromagnetic, mechanical and thermal point of view, in order to ensure the accomplishment of the Key Performance Indicators (KPIs) defined in the proposal stage, as well as their right operation in their final application. Downscaling procedure from 200kW to 75kW has been defined.

• WP5 has been kicked off in advance to follow the progress of the motor designs. The first technologies and integration analysis is reported in this deliverable.

• WP6 has defined single actions for each manufacturing activity planned. Sub-contractors have also been identified who will deal with some processing and motor assembling. The risks deriving from the prototyping steps and the mitigation actions have also been highlighted.

• WP8 covers the exploitation of the technological solutions developed within the project, for which a first Intellectual Property Rigths (IPR) draft and business plan have been defined. A technological watch of the main Electric Vehicles (EVs) markets and electric motor technologies has been performed.

• WP9 has led the dissemination and communication planning and already undertaken several actions to raise the awareness of different target audiences towards the project objectives and its research.
ReFreeDrive project will provide industry with turn-key solution for traction systems in EVs that compared to the existing state of the art brings the following advantages:
- higher power and torque density
- lower manufacturing and exploitation cost
- increased safety and fiability
- innovative technology solutions that can be manufactured at any OEM or specific company involved in general industrial induction motor sector
Hairpin winding illustration
Copper Rotor Induction Motor - cooling system 2 (automotive transmission fluid)
Cooling system - state of the art (Audi e-tron)
Copper Rotor Induction Motor - outer rotor
Copper Rotor Induction Motor - interior rotor
Copper Rotor Induction Motor - cooling system 1 (water ethylene glycol)