Design of a brushless PM starter-generator for low-cost manufacture and a high-aspect-ratio mechanical space envelope

Additive Manufacturing of Shaped Profile Windings for Minimal AC Loss in Electrical Machines

“…The electrical conductivity and hence the induced losses of the conductor material are temperature dependent. The electrical conductivity, σ T , at temperature, T , is given by (6) where T 0 = 20 o C, σ T 0 , and α are the reference temperature, electrical conductivity at the reference temperature and the temperature coefficient of resistance respectively.…”

“…The conductor shaping algorithm is demonstrated through the re-design of the N = 18 turn windings of a brushless Permanent Magnet (PM) automotive ISG, Fig. 12, [6]. The ISG is a variant of the 10 pole, p = 10, 12 slot, q = 12, topology with a single-layer three-phase concentrated winding and a quasi-Halbach PM array on the rotor.…”

“…• high intermittent overload capability • reliability and robustness • low acoustic noise and vibration With appropriate choice of pole-slot number and design, all these requirements can be addressed by an open-slot PM machine, however in high-frequency machines a significant disadvantage lies in the elevated AC winding losses due to a large exposure of the conductors to high magnetic fields around the slot opening, [6]. Where the hot-spot temperature of the windings ultimately dictates the electrical loading and hence torque capability of the machine as the winding current…”

“…In this paper, a method of determining an optimal shaped profile winding is presented which maximises slot area utilisation to achieve improved low-speed performance while maintaining low AC loss. The conductor shaping algorithm is demonstrated by the re-design of the windings of a 48V Integrated Starter Generator (ISG), [6] and aims to lay the foundation for design tools which can take advantage of the geometric freedom offered by present and future metal AM technologies.…”

A systematic experimental approach in deriving stator-winding heat transfer

“…The hardware exemplars have been selected such that a variety of the winding conductor types and constructions is considered. Starting from a single strand of round conductor [4], following with a multi-stranded bundle [15], a compacted type-8 Litz wire [2], a profiled rectangular conductor [16] and compressed multi-stranded coil construction [17]. Table I lists selected data for the analysed stator-winding exemplars including the electrical insulation system type/class and electrical wire details.…”