Self-Pumping Air-Cooling: A Novel Topology for Outer-Rotor UAV Generators under Windless Conditions

For hybrid-electric unmanned aerial vehicles (UAVs), the stable power supply from the onboard permanent magnet synchronous generator (PMSG) is critical. Overheating in the confined compartment can directly lead to power interruption and system failure. Therefore, proactively improving the thermal management is not only a key technical prerequisite for ensuring flight reliability and mission success, but also enhances the machine's efficiency and the overall power density of the system. Targeting the stringent spatial constraints in UAV applications, a novel self-air-cooling heat dissipation topology is investigated and highlighted on the rotor wall for compact outer-rotor generators. By utilizing the rotor's rotation to form a centrifugal fan, a ventilation hole is designed on the rotor outer wall. This innovation uniquely combines the structural space of the outer-rotor motor with self-air-cooling to directly enhance stator cooling efficiency. The parameters of the designed self-air-cooled heat dissipation topologies are optimized via a multi-objective genetic algorithm.