Analysis and Design of a Flat Wire PM Machine with Module-combined and Hollowed-out Stator for Aviation Electric Pump

This paper presents the analysis and design of a high power density permanent magnet (PM) machine for aviation electric pump. The developed PM machine with full-flooded cooling drives an electric oil flooded pump. A design of flat-wire concentrated winding and modular stator is used in the PM machine to improve slot fill factor and reduce manufacturing difficulty. Compared with traditional stator with round winding, the electric loading of the proposed stator is about 40% higher, which significantly improves the power density. In order to improve cooling efficiency, a combined cooling strategy with direct cooling in inner slot channels and indirect cooling in the hollowed-out stator teeth and yoke is adopted. Besides, the adoption of a rotor with trapezoidal halbach array and nonmagnetic metal sleeve has been investigated in this work to improve air-gap magnetic flux density. The AC losses and rotor windage losses have been studied. According to the simulation results, the power density of the new PM machine is much higher than the conventional machines with same power.