2022 IEEE/AIAA ITEC+EATS Student Design Competition

High-Voltage/High Power Distribution Propulsion Design for Zero Emission Aircraft

 

Announcement:

The IEEE/AIAA Transportation Electrification Conference and Electric Aircraft Technologies Symposium (ITEC+EATS) invites you to participate in the 2022 Aerospace Student Design Challenge.

Click here for a Flyer to share with your students.

Background:

Stimulated by ambitious emission reduction goals established by our modern society due to the climate, radical technologies and revolutionary design approaches are required for the future aviation sector. One way to achieve these goals resides in increased electrification of aircraft. As one future promising technology, advanced battery systems have been identified as one of the solutions for this electrification. However, the aviation sector has requirements for large amounts of electrical power at high voltage (up to megawatts) for such airborne applications. Because of the severe weight and volume constraints imposed to any aircraft design and stringent reliability and safety requirements, the design of a high-voltage/high power distribution propulsion system for zero-emission aircraft needs a careful examination. Such skills are now essential to engineers who design aircraft of the future.

Challenge:

The aim of the 2022 Aerospace Student Design Challenge is to trigger increased awareness in design towards managing phenomena linked to high voltage. The main goal is to design a high-voltage/high-power distribution propulsion system for a 4 E-motor full-electric aircraft. The entry into service (EIS) is 2040 for a 9 PAX + 1 crew + luggage aircraft with 260km range including a 50 km backup. The challenge includes electric distribution optimization, component sizing, safety considerations, and risks mitigation linked to phenomena like discharges or electric arcs. The objective is to have energy storage to supplement take off, climb, go-around, and emergencies via batteries and the 4 E-motors.


ELIGIBILITY

More than one design may be submitted from students at any one school.  Teams can consist of the following:

  • Undergraduate students
  • Graduate students
  • Combine Undergrad and Graduate students

SCHEDULE


Prize

  • Monetary Award: 750$ 1st prize, 500$ 2nd prize, 250$ 3rd prize

Requirements - (M) - Mandatory Requirement, (T) - Tradable Requirement

General Requirements

  • (M) Capable of taking off and landing from runways (dirt, grass, metal mat, gravel, asphalt & concrete)
  • (M) Minimum cruise speed of 500km/h.
    • (T) Target cruise speed: 550 km/h or greater
  • (T) Capable of flight in known icing conditions
  • (M) Meets applicable certification rules in FAA 14 CFR Part 23
    • All missions below assume reserves and equipment required to meet applicable FARs
  • (M) Engine/propulsion system assumptions documented
    • Use of engine (s) that will be in service by 2038.
      • Assumptions on at least specific fuel consumption/efficiency, thrust/power and weight should be specified.
      • Ensure that the power used by alternators, generators or other devices are accounted for. 
    • Use of electric motor(s) that will be in service by 2038 and document battery energy and power density assumptions based on reasonable technology trends.
      • Document system efficiency including at least the efficiency of the batteries, wires, power electronic controllers, thermal management system, connectors, motors and propellers to calculate a total propulsive efficiency.
      • Document electric propulsion system weight
  • (M) Show the emergency range to get to an alternate airport at the maximum feasible weight from an engine failure at 5000’ AGL (ISA+ 18oF) with electric power from batteries alone.
  • (T) Provide systems and power propulsion architecture that will enable high voltage/ high power flight
  • (M) Fulfill all safety considerations and high voltage issues management
    • Provide a market justification for choosing to either provide or omit this capability

Mission Requirements
Consider a typical aircraft with the following specifications:

  • Payload: 1000kg (9 PAX + 1 crew + luggage)
    • MTOW: 5650kg;
    • MEW: 3000kg excluding electric propulsion system*;
    • Aircraft characteristics: Length: 13m; Span: 17.5m; Height: 4.5m;
  • (M) Total embedded power of 2000kW;
  • (M) Thrust: 4 E-motor, two per wing
  • (T) Expected mass of electric propulsion system*: 1650kg (any more will reduce the payload capability)
  • (M) 260 km design range mission including a 50 km backup reserve
  • (M) 9000 m ceiling
  • (M) Minimum cruise speed of 500km/h.
    • (T) Target cruise speed: 550 km/h or greater
  • (M) Speed at take-off: 300km/h;
  • (M) Initial climb duration at sea level  (ISA+ 18oF) maximum, requested electrical power 1150kW;
  • (M) Cruise duration of 28minutes including the descent of 16minute requested electrical power 515kW
    • Maximum takeoff and landing field lengths of 300’ over a 50’ obstacle to a runway with dry pavement (sea level ISA + 18oF day).
    • Takeoff and landing performance should also be shown at 5,000’ above mean sea level (ISA + 18oF) as well as for grass & concrete fields at sea level (ISA+18oF)

Important Notes

*By electrical propulsion system the following components are meant: battery, dc/ac converters, dc/dc distribution, ac/ac distribution, E-motors. (This does not refer to the electrical system for, for example, avionics and navigation equipment, etc.)

The above powers and energies are the ones needed to ensure the mission, these figures may vary depending on the components efficiencies.


Report and Design Data Requirments

Please provide the following elements:

  • Given the above mission profile, a general architecture of the power distribution for propulsion, from the energy source to the loads (e.g. electric motors), through power converters, electrical wiring system, and protection devices;
  • A sensitivity study, in order to define the network voltage that is optimal, according to your calculation, and the impact on all components of the power chain, in particular the mass. Please detail how the voltage affects the mass of wiring cables and connectors, the cables and insulation thickness and mass, the choice of switching components in a converter and the converter topology. You should also discuss the voltage waveform (DC, AC and frequency, PWM and frequency) in the power chain.
  • A safety analysis, which describes the failures that are taken into account in your design, how the network design is fault-tolerant with respect to these failures, and how fault propagation is mitigated. 

 Below are further details, which should be included in your study.

  • Batteries: please provide your assumptions on the technology, the energy, and power densities, including the integration factor (i.e. the ratio of the power and energy density at cell level and full battery level).
  • Issues linked to high voltage: for the phenomenon listed below, indicate how you intend to mitigate them: the physical laws and/or design rules that you are using, whether protection components are needed in the electrical installation, etc... Keep in mind that some of the phenomena may be more or less critical, depending on the voltage kind (DC, AC / PWM).
  • Partial discharges;
  • Parallel arc (short-circuit between two conductors at a different potential), serial arc (electrical arc occurring on a line, for instance on a connector or terminal block);
  • Electrical shock to persons due to high voltage;
  • Overcurrent due to short-circuit

Expectations and Ranking

The expectations are divided into two parts: in the first part (⅔ of the total ranking), the main expectations are given. They consist of the definition of the electric power distribution, safety considerations and high voltage issues management. The second part (⅓ of the ranking) is a focus on key components: batteries, power converters, E-motors, wiring system.

1st part - Architecture of electrical distribution  (⅔ of ranking = 65 pts)
Item Comments Scoring
Electrical power distribution
Provide the overall electrical power distribution: batteries location(s), DC network, power converter(s), AC link to e-motors, e-motors A central battery is one option among others; 15 pts
Optimization of the DC voltage vs current, with a total embedded power of 2000kW The voltage and current have a direct impact on the number of batteries cells, the power converter topology and switches choice, the wires section and masses, the risk of partial discharges and electrical arc, etc... 10 pts
Safety considerations for the electrical architecture
Provide a list of main failures and how the electrical distribution system is fault-tolerant 5 pts
Describe how redundancies are provided in case of critical components failure, power cables segregation 5 pts
Describe how critical faults propagation is mitigated 5 pts
Describe protection components and what risks are addressed by these components.  Examples are: fuses, circuit breakers, RCCB... 5 pts
Pls give main certification requirements for the electric distribution, and how they are taken into account by your proposed solution Pls consider FAA and EASA requirements 5 pts
High voltage issues
Partial discharges mitigation Explain sizing rule(s), and illustrate it on a simple case, for instance two cables at different potentials. Do not forget to consider the pressure 5 pts
Parallel arc mitigation Explain how the risk of parallel arc is mitigated in your design, with what components, both on DC and AC sides. Estimate the level of short-circuit current which seems acceptable, in order to select the protection component. 5 pts
Serial arc mitigation Same as parallel arc 5 pts
2nd part - Components analysis (⅓ of ranking = 35 pts)
Batteries
Cells technology, energy density, power density Aircraft entry of service is 2040 2 pts
Energy density and power density at battery level Take into account the mass of all additional protection components: BMS, thermal runaway mitigation, etc…. 2 pts
Batteries mass calculation Batteries are never used from “full to empty” SOC 2 pts
Batteries distribution in the A/C A centralized battery is one option among others 2 pts
Thermal runaway mitigation Explain how it is taken into account in the battery of your choice. Standards guidelines are useful. 2 pts
Wiring system
Cables sizing (DC and AC PWM) and mass estimation

Explain sizing rules to evaluate the conductors section, according to the current to be carried out and your hypotheses of temperature.

In AC, do not forget the skin effect.
5 pts
Connecting devices (DC and AC PWM) Explain what kind of connecting devices you are using (connectors, lugs, terminal block) on DC side and AC/PWM side 5 pts
Power converter
Converter general topology Number of levels 2 pts
Switches technology selection Provide your selection of switch: technology, rated voltage, rated current, reference. Take components derating into account. 2 pts
Characteristics of motor drive: voltage switching frequency and current frequency Example: PWM (pulsed-width modulation) 2 pts
Converter mass Do not forget EMI filters on DC and AC sides 2 pts
E-motor
Technology of motor 2 pts
High-level characteristics: rotation speed, number of pair of poles This shall be consistent to the power converter drive strategy 2 pts
Motor mass and size and efficiency 3 pts

COPYRIGHT

All submissions to the competition shall be the original work of the team members. Authors retain copyright ownership of all written works submitted to the competition. By virtue of participating in the competition, team members and report authors grant AIAA and IEEE a non-exclusive license to reproduce submissions, in whole or in part, for all of AIAA’s and IEEE current and future print and electronic uses. Appropriate acknowledgment will accompany any reuse of materials.


CONFLICT OF INTEREST

It should be noted that it shall be considered a conflict of interest for a design professor to write or assist in writing RFPs and/or judging proposals submitted if (s)he will have students participating in, or that can be expected to participate in those competitions. A design professor with such a conflict must refrain from participating in the development of such competition RFPs and/or judging any proposals submitted in such competitions.


Reference Material

FAA Part 23