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Modular, scalable, multi-funtional, high power density power controller for electrical taxi

Periodic Reporting for period 3 - E-TSIN (Modular, scalable, multi-funtional, high power density power controller for electrical taxi)

Reporting period: 2019-01-01 to 2020-03-31

The E-TSIN project is part of the global e-TAXI program, one of the most important initiatives at European levels for reduction of acoustic and environmental contamination around airport, and contributing also to reduce operational cost of the single aisle and regional aircraft by reducing fuel consumption on ground.
To have clear view of the problems and potential benefits, it´s very important to highlight that aircrafts are currently designed to optimize performances in flight. This means, that aircraft design and performances, are not so good on ground. This is the case of the “on-ground aircraft movement function”, or “taxi function”. When aircraft is stopped in parking, at finger or in hangar, an airport tractor-vehicle is needed to perform backward and slow movement of that aircraft. Then, when aircraft is in a safe and free position, aircraft can start-up main engines and perform a toward movement by itself. Nevertheless, this movement on ground is very poor in efficiency, as it´s produced in an indirect way, by effect of the air pushed by the main engines, and needing high power to move the aircraft inertia. Therefore, a high level of fuel consumption and generation of a high level of contamination and high level of acoustic noise.
But, advances in the power electronic technologies and energy storage devices, are an opportunity to improve drastically the efficiency of the aircraft on ground, at the same time that reducing environmental and acoustic contamination, and trying to keep or improve the global efficiency of the aircraft (ground/flight performances, maintenance/operational costs, safety and reliability aspects, etc…).

So, as commented before, power electronics and energy storage systems are a key point to achieve the global objectives of the “e-TAXI program” and new more “green aircrafts”.
Therefore, “E-TSIN project” is applying new technologies in power electronics to achieve these efficiency (as use of new components based in WBG, new power electronics technologies and new control techniques) and expected performances of the e-TAXI system, but, maintaining the contribution to the aircraft objectives of weight, volume, cost, operability, maintainability, reliability and safety.
Then, we can say that the main objective of the “E-TSIN project” is to develop a power supply and motor controller unit, for high power, high efficiency, based in new technologies and achieving a low weight and low volume.

But also, the unit under development will comply with the following:
- Be capable to control in speed and torque, in order to be adequate to the aircraft needs.
- To ensure interface with the rest of e-TAXI parts, as new electrical motors (for a/c wheels), the “e-TAXI controller” and with the dedicated aircraft electrical network.
- To ensure also performances and future integration with a dedicated energy storage system, in order to increase more the system efficiency, by recovering part of the energy from braking actions (that also will reduce the brake pads wear).
- To perform a design by capable to be scalable and integrable in several and different aircrafts and air platforms.
According to the required global objectives for the “new green aircraft”, “e-TAXI program” and “E-TSIN project”, this project was plannified and is being developed based in several work-packages and several activities.
So, during the first part of the project, several analyses of the SoA in power electronics components, topologies and control technics were done, in order to select the best design to comply with requirements of weight, volume, scalability, reliability, safety and feasibility for future increase in technological readiness level and potential future integration in real aircraft.
During this first stage, also several pre-prototypes, based in previous experiences, were used to validate control techniques and result matching in power scalability and modularity versus performances and integration aspects.
Then, in the second part of the project, being aligned with the second reporting period, a baseline for the development of a TRL3 design and prototype was done. Moreover, this TRL3 design was validated in isolated mode, but also tested and integrated with the rest of the e-TAXI system under development, as motor, mechanical interfaces and aircraft system controller simulator.
Second part of integration activities and recollection of data were part of the third reporting period of this project. But after finalization and recollection of data and experiences of the TRL3 design, a new baseline for TRL6 design was obtained at the end of this third reporting period.
So, the third part of the project consist in the optimization of the design to achieve a TRL6 target at the end of the project, including complete new development, new prototypes manufacturing, testing and integration with the rest of the system. This final part that was started al the end of the third reporting period will be extended along the fourth reporting period and up to the end of the project.
As commented before, during the first part of the project, and analysis of new power electronic components was done, so as selection of topologies and control techniques.
So, as output of these analyses but also taking into account requirements of the TM and global objectives, a topology based in new SiC devices was selected. This allowed reduced the weigh and volume of the first prototype if compared with Si-IGBTs technology. But also other important requirements and problems leaded the project in an unknown environment, as the importance of the future EMI/EMC aircraft requirements, were the inherent behavior of the SiC devices, with very high dV/dt performances, and where in order functions can be a advantage, here is producing disadvantages, and requiring use of important filters.
Also control of the new motors, requiring special performances was a challenge, and requiring adaptation in the specifications and in the design, in order to comply with the future safety requirements for design feasibility for the future potential integration in real aircraft.
Now, with the new development in TRL6, the E-TSIN consortium is trying to apply its previous experiences in aeronautical sector and lessons learnt from the TRL3 design to try to optimize at maximum the design in performances, weigh and volume but keeping in mind, the rest of future aircraft requirements. And of course, achieve the correct integration and functionality in the frame of the e-TAXI program.
Of course, all the knowledge and lessons learnt gotten and applied during this project will allow to this European Consortium to be in a confident and first position for the future industrial development and implementation. This inside of the consortium and with the TM and CSJU is being done in a professional, confident and w2w way, and a clear global objective for all the stakeholders.
An example of this transversal collaboration is being the flexibility of the consortium against the necessary changes in the TM specification and the availability of the resources in the consortium and TM for testing aspects and in one side as in other.
This also is producing a mature and confident relationship between the parties to continue in future collaborations and potential future industrial development and exploitation. As for European market and future applications (different aircraft sizes) and for other potential world markets.