System Modeling and Control Strategy of a Superconducting Powertrain for Electric Aircraft

Aviation contributes approximately 2.4% to the annual global <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{CO}_{2}$</tex-math></inline-formula> emissions. This serves as a driving force behind the development of a fully electric, zero-emission aircraft. One possibility is using liquid hydrogen at a temperature of 20 K that fits very well with lightweight and efficient superconducting components within an electric aircraft to produce energy through a fuel cell, as it has the highest energy content per weight among all energy carriers. A potential powertrain of a large electric aircraft comprises various components, including the motor, DC/AC inverter, DC and AC cables, fuel cell, and fault current limiter. Building on previous work that modeled superconducting fault current limiters and cables using MATLAB/SIMULINK, this study focuses on the motor, DC/AC inverter, and fuel cell. For the fuel cell, even though most publications propose only the resistive-capacitive (R-C) electrical equivalent circuit, in some cases, a resistive-inductive (R-L) behavior or sometimes a combination of both is detected. Therefore, a novel model that covers all scenarios is proposed for this work. Furthermore, the electrical model and control scheme of the permanent magnet synchronous motor (PMSM) via a DC/AC inverter are detailed. Additionally, an algorithm is developed to protect the inverter during short circuits. The simulation flight scenarios are employed with input speed as a key parameter to simulate the complete integrated system. Moreover, a DC pole-to-pole short circuit is analyzed to simulate the system's behavior in fault conditions. The simulation shows the entire system's behavior during nominal test flight scenarios and short circuit events. Moreover, these models give the user flexibility to adjust the powertrain properties.