To ensure that the NRC has the capabilities to support industry in this emerging field, the Hybrid-ElectricAircraft Testbed (HEAT) project was proposed in early 2017. To facilitate the growth of these capabilities, the aim of the project was to gain practical experience in the process of installing an electric motor onto an aircraft. More specifically, a Cessna 337G – a push-pull aircraft – was procured and the rear engine was to be replaced with a fully-electric powertrain, including the installation of an electric motor and a battery module. Through the development of the electric powertrain, real-world experience in the installation of electric motors and power supplies in an aircraft were gained, including developing adequate cooling and safety strategies which could help inform industry and regulators.
light weight operation. For designing such systems, different local strategies have been developed but no global optimization has been performed so far. In this paper, we present at first two approaches, a classical approach used at the moment and a utopian approach involving all devices in a single optimization loop that should provide the ideal design. Then, a new approach based on collaboration is presented and a particular attention is paid on the data exchanged between subsystem designers. We compare the three strategies applied to the sizing of a whole network of more electricaircraft. A simplified case study with only two components is considered to illustrate methodological issues.
To cite this version : Hadbi, Djamel and Retière, Nicolas and Wurtz,
Frederic and Roboam, Xavier and Sareni, Bruno Comparison between system design optimization strategies for more electricaircraft networks. In: 13th International Workshop on Optimization and Inverse Problems in
Souleman NJOYA MOTAPON ABSTRACT
As the aircraft industries are moving toward more electricaircraft (MEA), the electrical peak load seen by the main and emergency generators becomes higher than in conventional aircraft. Consequently, there is a major concern regarding the aircraft emergency system, which consists of a ram air turbine (RAT) or air driven generator (ADG), to fulﬁll the load demand during critical situations; particularly at low aircraft speed where the output power is very low. A potential solution under study by most aircraft manufacturers is to replace the air turbine by a fuel cell hybrid system, consisting of fuel cell combined with other high power density sources such as supercapacitors or lithium-ion batteries.
Fig. 1. Series hybrid electric powertrain architecture.
Such system integration takes into account the main environmental constraints, related to partial discharges due to new high power and ultra-high voltage standards . It is already known from other studies] that integration of a hybrid-electric propulsion system into an aircraft tends to increase its mass even by considering optimistic assessments (electric motor specific power higher than 10kW/kg). Disruptive technologies have to be found in order to promote the electric flight opportunity. In HASTECS project moderate targets have been chosen. The first to be reached by 2025 is to get specific powers of 5 kW/kg for electric motors (including the cooling system) with partial discharge tolerance, while15 kW/kg are imposed for the power electronics and its adjoined cooling system. The second target by 2035 is to reach or exceed 10 kW/kg for electromechanical actuators and 25 kW/kg for inverters (cooling systems are included in all cases). This study aims at a multidisciplinary design optimization (MDO) through analytical models of each device of the hybrid electric powertrain with a fixed aircraft architecture. In our case, a series hybrid-electricaircraft architecture, involving system design oriented models to optimize the propulsion system, is assessed. Estimating the Maximum Take-Off Weight (MTOW) and its snowball effects, the fuel burn can also be assessed and is seen as the optimization objective. It can be derived by means of the simplified but realistic integrated design process (cf Fig. 2 ) already validated with reference to aerodynamic models 
MPT Mechanical power transmission
PDE Power drive electronics
Safer, cheaper and greener technologies are important initiatives for the next generation air transport in upcoming decades. In response to these needs, the aerospace industry is looking for an innovation (incremental or disruptive) in safety- critical actuation systems. In recent years, a significant interest is towards “more electricaircraft”. The trend is to increase the usage of power-by-Wire (PbW) electrical actuators: electro- hydrostatic actuator (EHA) and electro-mechanical actuator (EMA). These are envisioned to take the place of conventional hydraulic servo actuators (HSA). Compared to EHAs, EMAs totally remove the central and local hydraulic circuits, resulting
To cite this version : Hadbi, Djamel and Retière, Nicolas and Wurtz,
Frederic and Roboam, Xavier and Sareni, Bruno Comparison between system
design optimization strategies for more electricaircraft networks. In: 13th
International Workshop on Optimization and Inverse Problems in Electromagnetism, 10 September 2014 - 12 September 2014 (Delft, Netherlands).
The VSI (Voltage Source Inverter) is a classical two-level structure ( Fig. 2 ) associated with a Space Vector Pulse Width Modulation (SVPWM) strategy. The multi-physics VSI model includes:
– A time–frequency approach which allows the determination of the electrical variables (currents and voltages) in time and frequency domains at the VSI input and output. In particular, this approach quickly computes the time evolution of electric variables over a period of the modulation signal at steady state operation. From the SVPWM strategy and the knowledge of VSI switching states, HSPMSM stator voltages are constructed. Then, HSPMSM line currents are easily computed in frequency domain from the HSPMSM impedance using the fast Fourier transform. The corresponding time evolution of HSPMSM currents can also be obtained over the modulation signal period with the inverse fast Fourier transform. Finally, the DC current at the VSI input is deduced from HSPMSM currents and VSI switching states;
4. Sensitivity analysis of electric motor based on the sizing model:
In this section, only the electric Motor is focused. The sizing model developed in for electric motor design has been taken in order to illustrate the interest of this approach. After the choice of the index calculation method, input variables (and subsequent bounds) have to be determined. In our case an input vector including thirteen variables has been chosen for the motor model inputs [Erreur ! Source du renvoi introuvable.]. It is composed of:
Keywords: Optimal design; Multi-level optimization; ATC (analytical target cascading); Power integration
Thanks to the significant advances in aircraftelectric technologies, integration of electrical energy has significantly increased in the last century [ 3 , 4 , 10 , 16 ]. Fig. 1 shows the trend in the power demand in commercial aircrafts. The main advantage of more electrical architectures is related to energy management as electric generators are controlled to match exactly the demand of consumers, reducing thereby losses contrarily for example to pneumatic systems powered by bleed-air at the operating pressure of the engine, irrespective of the needs of the systems [ 9 ]. Additional advantages of electrical systems are due to the opportunity for an easier power management through shared sources [ 4 ]. Moreover, the potential of improvements in the power density (power to mass ratio) of electrical systems is seen as high [ 9 ] while hydraulic and pneumatic systems are stabilized being more mature. Table 1 resumes the benefits of electrical systems compared to hydraulic, mechanical and pneumatic systems [ 4 ]. However, a separate design process of all the different electrical systems would not lead to an important gain compared to conventional systems [ 1 ] (e.g. fuel burn, integrated mass and drag impact).
that reason, the proposed real-time model in Figure 4.2 is the one used during simulations, since the way it is divided makes easier the transition from the off-line model to the real-time model. Moreover, the fact that each AC bus is a subsystem separated from the rest of the AC busses, makes it easier to output test signals in case of an HIL testing. These tests can be of great benefit while designing and integrating the electric system of the aircraft, since failures can be determined at an early stage of the aircraft's conception, helping significantly to reduce the test time and costs. In addition, HIL systems typically have the ability to automatically run through tests automatically by using a script, so that testing can be done without damaging equipment or endangering lives, and potentially damaging conditions can be detect and reported. Or even better, an electric abnormal behaviour inside the aircraft can be easily recreated and simulated with a specific protective or control device using HIL.
b Université de Toulouse, Toulouse 31071, France
Abstract. The aircraftelectric network is a complex system, consisting of many different elements integrated to form a unique entity, designed to perform a well-defined mission. In the current state, the network conceptual design is based on standards defined by the aircraft manufacturer. As a consequence, electric subsystem suppliers are doing local optimizations to fulfill these standards in a separated way through a “mechanistic approach”. This results in a set of optimized subsystems which is not necessarily “optimal” with respect to the network level. To overcome this problem, we present a design approach called EPFM (Extended Pareto Front Method) based on separated subsystem optimizations which aims at finding an optimal configuration of the electrical network at the system level. The EPFM is discussed with regard to the computational cost and the collaboration requirements in the aeronautical industrial context and compared with the classical mechanistic approach.
Nowadays, transport is the worldwide fastest growing sector  which significantly contributes to environmental degradation. Finding sustainable solutions is a key challenge to solve this issue especially for the aircraft sector which represents about 2% of the global CO2 emissions. The Clean Sky (H2020 EU) project assists with the aircraft manufacturers ﬁnding aircraft cleaning/noiseless solutions. Currently hybrid-electric or all electric aircrafts are not commercialized but several aircraft manufacturers explore the future of electric flight. Airbus has teamed up with Rolls Royce and Siemens to build a 100-passenger hybrid-electric technology flight demonstrator, E-Fan X, scheduled for 2020 . The same year, backed by Boeing and Jetblue technology ventures, Zunum Aero, a hybrid electricaircraft manufacturer startup, plans to fly a 12-passenger hybrid electric prototype in 2020 . The hybrid electric technology is taking off and the studies too.
Ballistic Recovery Systems
Ballistic recovery systems (BRS), or airframe parachute systems, are increasingly pop- ular on small GA aircraft and are widely proposed as a mitigation for total electrical system failure in electricaircraft, especially for Multirotor or DEP Hybrid lift config- urations in vertical flight modes where autorotation or gliding is not possible. Current BRS technology has been shown to be eﬀective, but only above a certain combina- tion of airspeeds and altitudes. Figure A-5 shows the oﬃcially demonstrated (dark blue) and likely (light blue)eﬀective deployment envelope of the ballistic recovery sys- tems for a Cirrus SR20 based on the published handbook. This system is the SR20’s means of compliance with the spin recovery requirements. The deployment time and corresponding altitude loss (from time of system deployment until full inflation of the canopy) of a BRS system is a function of both altitude and airspeed. In the case of the Cirrus system that altitude loss increases from no more than 400ft if the BRS is deployed while the aircraft is in straight and level flight to more than 900ft if the aircraft is in a spin. While sucessful lower-altitude deployments have been reported  this requires higher speed and is not guaranteed. Vehicle weight and the details of the parachute design can significantly change the eﬀective deployment envelope.
Denieul, Y., Bordeneuve-Guibé, J., Alazard, D., Toussaint,C., and Taquin, G. (2017). Multi-control surface optimization for blended wing-body under handling quality constraint. Journal of Aircraft, 55, 638-651.
Case study : Vertical Tail Reduction using Differential Thrust
At ISAE-SUPAERO and ONERA, design of distributed electricaircraft is tackled in researches focusing on the use of differential thrust to increase directional control authority . In this study three types of coupling appear; 1. The size of the vertical tail depending on flight safety rules in case of engine failure, 2. The dual function of propulsion, generation of forward thrust and yaw moment, 3. The aerodynamic interaction between propeller slipstream and wing.
The aim of this paper is to show how different approxima- tions derived from the original non linear and retarded system may result in different identifiability conclusions. The presen- tation is organized as follows: Section 2 presents an analytic approach based on the linearization of the model in the vicinity of a nominal trajectory. An algebraic approach is developed in Section 3, where the nonlinearities are maintained while the retarded terms are assumed known or approximated using Tay- lor expansion or Pad´e approximation. Section 4 presents some concluding remarks. Most of the computations related to the aircraft models are implemented in Maple, a symbolic compu- tation language.
compound, resulting from the voltage-induced 3d/5d band filling 1,7 . In Ref. , the change
in the electron density was obtained by creating an electric field between the sample and a so-called counter-electrode, both immersed in a liquid electrolyte. The large dielectric constant of the so-called double-layer formed at the sample surface permitted significant charging upon applying a moderate voltage below 1V.
– World-class scientific expertise in niches critical to PHEV
technology (electric storage, motors, inverters, chargers and their integration), and policy and regulatory development
• Electric Mobility Program will identify and undertake key activities where Canadian R&D can address issues currently limiting
Solving Aircraft Conflicts: data resources" to which we have assigned id #88.
In the domain of air traffic, two planes are considered as in a conflict situation when their trajectories cross each other in certain circumstances of distance at the same time. Air Traffic Management (ATM) has adopted some rules to avoid such conflicts but the increasing density of aircraft flights makes conflict situations more and more difficult to anticipate and solve in an optimal way. Decisions to solve conflicts are made manually in real-time and consist of changing aircraft trajectories to maintain a safe distance between planes. When a conflict is identified, the Air Traffic Controller (ATCO) has to make a quick decision about the best possible solution using his/her knowledge and experience. ATCOs have to take into account all the aircraft flight parameters such as its speed, positioning coordinate, destination, flight plan, as well as its environment, for example, weather, wind direction, military zone, etc. and the other flights. The air traffic growth is so that the ATCOs will not be able to face conflict solving in the future if they are not assisted effectively. More