Design route towards a PM machine for rotorcraft environments

This paper discusses the design route followed in the development of a Permanent Magnet (PM) machine for electrical power generation on board a rotorcraft (helicopter). The focus of the machine design is to optimise system power density, efficiency and robustness – all of which are crucial considerations in aerospace applications. A matrix of designs was created consisting of two stators with different winding conductors – copper and aluminium – and three rotors, each using different containment sleeve materials. These include two semi-permeable metallic sleeves, which act to decrease the effective airgap. Combinations of the different materials will yield different system-level power densities and efficiencies. Here, all the designs are presented along with the initial test results for the baseline machine combination validating the design predictions.