Topology-aware nullspace control allocation for eVTOL powertrain current protection

This paper presents a topology-aware control allocation strategy to mitigate thermal risks in electric Vertical Takeoff and Landing (eVTOL) aircraft. By integrating the powertrain architecture directly into the control design, a control allocation method is proposed that actively regulates the electrical load distribution among motors and battery packs. This method exploits the null space of the control effectiveness matrix to minimize the maximum current in both motors and battery packs without altering the primary force and moment commands. The efficacy of the current regulation algorithm is validated through comprehensive simulations on a Lift-plus-Cruise eVTOL platform. Results demonstrate that the proposed algorithm significantly reduces electrical stresses during both transient maneuvers and steady-state operations. It effectively protects the powertrain under nominal conditions and in the event of motor or battery failures. Moreover, the study characterizes the trade-offs between regulation aggressiveness and control smoothness, and discusses the priority distribution among motors and batteries. These findings offer a foundation for integrating hardware constraints into flight control laws for future eVTOLs, enabling more resilient distributed electric propulsion systems.