eVTOL Mission Simulation For Energy Management

While reducing carbon emissions in aviation is a major challenge of today, leveraging electrification and fuel cell applications is the key solution in the field. From small electric aircraft, to vertical take-off and landing aircraft (eVTOL), to urban air mobility vehicles, the range of developments underway is broad. But so are the challenges.

Overcoming the Challenges of Commercialization

When it comes to viability of eVTOL commercialization, there are two primary challenges to overcome. The first challenge, of course, is developing and complying with regulatory requirements. The second challenge is understanding the total cost of ownership (TCO) and return on investment (ROI) of the eVTOL as an individual and fleet.

AVL is focused on helping customers minimize TCO and maximize ROI by optimizing the propulsion system—including battery, e-motor, and other power electronics—for reliability and energy efficiency.

Minimizing Effort with E-Motor Emulation

Traditional testing of inverters and e-motors is typically done with physical hardware. This works well for customers looking to test anything specific on the e-motor architecture or behavior. However, for engineers looking to test only the inverter, traditional methods with a physical e-motor is excessive from the perspective of cost, effort, and risk.

The AVL Inverter TS™ allows for physical inverter testing while using a virtual representation of the e-motor. The power of this system comes from the speed, because the inverter can operate at a faster-than-real-time manner (without the physical E-Motor), therefore reducing testing time with emulation.

With this E-Motor Emulation method, engineers can insert faults and variations into the e-motor like short-circuits, manufacturing variations, etc., and determine how the entire system will behave.

Modeling an eVTOL Flight with Simulation

To better understand the energy storage requirements of an eVTOL, AVL uses system simulation to explore battery architectures. AVL CRUISE™ M is a multidisciplinary vehicle system simulation tool for mobility concept analysis, subsystem design and layout, and virtual component integration, and has multi-physics simulation capabilities.

Within AVL CRUISE M is a library containing more than 80 off the shelf battery cell models. The library includes a wide variety of energy densities and power densities that have relevance for all industries, from aviation to automotive to consumer electronics.

In AVL’s latest study, the team explored the viability of four industry-available battery cells. Two simulations would be performed for each cell, including a fast charging test and flight mission simulation.

The first simulation would test fast charging capabilities of the battery cells. CRUISE M allows engineers to monitor numerous KPIs safely, including those difficult to monitor like anode potential. It is commonly accepted that a cell is experiencing aging if the anode potential is less than zero. In AVL’s test, the “Cell C” cell charged quicker than all other cells due to not needing to de-rate because it maintained an anode potential limit greater than zero.

The second test would be the flight mission simulation for a delivery eVTOL. It would perform a 16-minute flight mission and fly at an altitude of 1,000 meters. When the simulation was performed, it was determined that “Cell D” ran out of energy and could not complete the mission.

One cell which had enough energy remaining to perform a two-trip flight and that was “Cell A”. It also had one of the lowest operating temperatures during the flight mission. A slightly more conservative/slower charge does not outweigh the two-flight benefit!