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Simcenter Amesim: Aircraft Electrical Systems solution

Today's aviation industry faces major challenges:

1) Secure and abbreviated integration of avionics systems

• Shared design responsibility between partners
• Increasingly complex and interacting systems with complex control strategies

2) Reduction in development time and cost

• Addressing design and integration issues earlier in the development cycle
• Reducing the number of actual prototypes and testing

3) Management of innovations related to intelligent systems

• Parallel design cycles for physical and control system
• The need for a common system model between systems and control teams

Simcenter Amesim can greatly contribute to solving these challenges.

Simcenter Amesim is an integrated, scalable system simulation platform that enables system simulators to virtually evaluate and optimize the performance of mechatronic systems. Increases overall system engineering productivity from early development stages to final system verification and calibration.
Ready-to-use multiphysics libraries combined with application- and industry-oriented solutions supported by powerful platforms enable systems simulation engineers to quickly create models and accurately perform analyses.

Simcenter Amesim is an open environment that can be integrated into business processes. It can be easily interfaced with major software packages CAE, CAD and control sw, it can cooperate with Functional Mockup Interface (FMI), Modelica® and interface with other Simcenter and Teamcenter® solutions. Simcenter Amesim is also available on Rescale's cloud platform (as SaaS and on-demand HPC).

Typical applications in the aerospace industry are:

• Electric aircraft propulsion
• Air cooling of the battery
• Electric motor cooling
• Variable frequency generator
• A variable frequency generator coupled to an impingement air turbine
• Generator with variable frequency and commutatorless excitation
• Energy management and thermal integration

Electric aircraft propulsion

Hybrid and electric propulsion is the hottest topic in the aviation industry right now. New entrants (Siemens, Uber, Google - to name a few)  are investing in new propulsion ideas. These new ideas require powerful and reliable simulation tools to be pre-tested before any prototype is created (for these companies, there is money at stake).

Quasi-static and simple models of batteries, motors and inverters are needed to rapidly test hundreds of design parameters. Simple models in Simcenter Amesim are built to analyze a series hybrid propulsion system.

This way you can get answers to the questions:

Can the electric motor provide the necessary shaft power to the propeller or do we need to increase it a bit?
Are the motor windings within the temperature limit tolerated by the terminal insulator?
At the end of the flight, is the battery charge and energy within the limits tolerated by the standards (such as GAMA standards)?
Can the ICE provide enough power to charge the battery and maintain the voltage in the cruising phase?
Air cooling of the battery

Battery heat management is a big topic. It is solved by stacking different cells to get a battery of necessary properties. In addition to the electrochemical phenomena in the battery, the heat exchange between the cells and the environment is also modeled. Thanks to the electrothermal approach, the temperature of individual cells can be monitored during different environmental conditions (throughout the flight).
Variable frequency generator

Another application deals with the synchronous generation system used on most aircraft. When the speed of a synchronous generator changes or the power consumption suddenly increases, it becomes destabilized. Torque and voltage can drop and go through certain oscillations.

With the simulation model in Simcenter Amesim, torque and voltage transients can be analyzed and the generator can be tested with the potential sudden changes and voltage/torque oscillations it may experience. You can specify specific points in time to analyze more deeply what is happening.
If necessary, the generator requirements can be adjusted so that the voltage remains within the limits tolerated by the standards (eg STD-MIL 704F).

On most commercial aircraft, the generation system consists of a synchronous generator and an excitation system connected to it (two other smaller synchronous generators). A series of diodes and converters are used to regulate the mains voltage. Thanks to Simcenter Amesim's approach to easy assembly of models, building such a system from standard blocks is not that complicated.

Depending on the steady-state power requirement and network transients, the excitation system can be pre-sized to ensure that the main generator receives enough excitation power to supply and absorb the voltage and current transients. The interaction between the generator and other network components such as transformer rectifier units can also be simulated here.

For emergencies, the synchronous generator is driven by a ram air turbine (RAT). Based on the emergency power requirement, it is important not only to properly size the generator, but also to check that the turbine can convert the aerodynamic power into sufficient mechanical power to drive the generator and the loads it supplies. A high-level turbine model parameterized by radius and aerodynamic loss can be used. Based on various inputs (electric power, mission altitude, and speed), turbine power demand and pitch can be assessed. A powerful turbine hidden under the plane's belly helps mitigate the consequences of emergency scenarios. Thanks to the simulation in Simcenter Amesim, the design of such a solution is much easier.