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

Periodic Reporting for period 2 - E-TSIN (Modular, scalable, multi-funtional, high power density power controller for electrical taxi)

Reporting period: 2017-07-01 to 2018-12-31

The E-TSIN project is framed within the scope of a global program for application of electrical mobility for aircrafts on ground (e-TAXI). Currently, the aircrafts don't use direct rotation over their wheels but push air energy coming from main engines are used on ground to overcome aircraft weight and inertia a to produce a torque over the wheels and therefore a longitudinal movement of the aircraft on ground.
This means that this traditional way to move the aircraft on ground is very simple but at the same time is very inefficient, leading to produce an important fuel consumption and a lot COx/NOx emissions on ground and additionally to a big impact in the acoustic noise on ground in the airports.
Moreover, this traditional way of working is only valid for forward movement, leading to need an external tractor vehicle for backward movement or movements and parking actions when main engines are stopped.
So, in order to improve the efficiency of the aircrafts and also, and more important nowadays, to reduce air and acoustic contamination, the industry with the scientific community started to think about ways to improve both aspects (efficiency and contamination), to release the challenges and to solve the technical problems.
Solving these problems, the new concept of aircraft movement will have a big and direct impact in the nature and in the society.
And regarding to the question about how the scientific community and industry have proposed the problem, have been using electrical energy for direct application and movement of the aircraft landing gear wheels. This new aircraft landing gear concept is globally known as e-TAXI, or electrical-TAXI, where ""TAXI"" is known as the movement of the aircrafts on ground in the different airports.
And regarding to the question about how the E-TSIN project is contributing to achieve the objectives of the global e-TAXI program, we can summarize in the following:
• Analysis of SoA in power electronic and control strategy to be applied over a e-TAXI.
• Based in these studies and taking into account TM specification, aircraft customer integration requirements, airline need and impacts and future qualification and certification, and feasibility study to select the optimum topologies and design will be performed.

According to the initial schedule of the E-TSIN project, for the Period-2 (from 01/07/2017 to 31/12/2018), the main objectives and its status at the end of P2 are:
Ob1 --> Signature of the different agreements between the parties (Grant Agreement Consortium
Agreements and Implementation Agreements). OK in P1.
Ob2 --> Project development Plans. OK
OB3 --> Project Specification agreement. OK in P1.
OB4 --> Project baseline. OK
OB5 --> Initial dissemination and exploitation plans. OK but to continue in P3.
OB6 --> Advance in the modellization & simulation of the power and control stages. --> Partially-OK as models not finalised as currently under validation updating based in test results.
OB7 --> Development of the control and power stages and TRL3 prototyping --> OK.
OB8 --> Integration tests --> Partially-OK in P2 (ok in-house, in e-TAXI test rig in Jan-2019).
OB9 --> Design evolution to TRL6 --> NOK due to Project/progarm delay.

Previously to this project, and as commented before, the E-TSIN Consortium has experience in application of power electronic technology and technics for electrical movement. So, CEIT-IK4 has developed an electrical power system for supply and control electrical motors in an hybrid bus and Indra has also developed technics and system for electrical movements in radar systems and with a big experience in the development of aeronautical products.

Regarding to the global objectives commented before, the activities performed by the Consortium in the first period of the project could be summarized in the following:

Analysis of requirements from the different specifications of the topic manager. Due to the evolution of the aircraft requirements and e-TAXI development, several specifications with different scope of the functionality were performed.
In parallel to the requirements analysis and understanding of this, modellization and simulation of the power stage and its associated control were performed. A lot of simulation and control predesign were performed to get a correct answer of the power output and motor control for the different working scenarios (or e-TAXI profiles) and different expected performances of the electrical motor under development (in parallel to the E-TSIN project).
Analysis of SoA over power topologies, control and components were performed in parallel to take into account in the parametrization of the models and analysis of feasibility for the future application in the equipment predesign.
Dedicated and detail analysis of modularization was done in this period. The idea was to know in advance the key parameters in the development of the global E-TSIN system (or EPS or power stage). So matching strengths and weaknesses of a configuration based in an central/unitary design or based in a modular approach (several power modules or MCUs).
Moreover, in order to validate several of the conclusions between modularity vs. unitary topology, several miniprototypes were built and tested.
Just at the end of the period, final inputs of the specification, simulations, pre-analyses and tests were available to be presented in PDR and with the target to agree a design baseline with the topic manager.
Based in the studies of the state of the art and main contributors for the technological challenges and their associated impacts, used along this Period-2, we can say that:

During the second period of the project, the baseline of the power inverter was changed due to the new restrictions in the e-TAXI system required but the aircraft companies and safety aspects. So, it was necessary to increase the power baseline, to cover a control adaptation stage to control as in speed mode as in torque mode and to include additional functionalities for control and monitoring as with the motor mechanically loaded or partially loaded. Then the new objectives and achievements for this period were:
- At the end of this period a new baseline was achieved and preliminary design accepted.
- Also, in the first third of the P2, detail design for the first prototype was also achieved and manufactured launched.
- Initial prototype was available in the second third of the P2.
- And during the final third of the P2, the prototype was tested in simulation mode and with initial real motor.