Steven Hayslett

A new and efficient analytical optimization methodology for the design of rotor features is developed and used in interior permanent magnet motors (IPM). The analytical methodology is based on an extended winding function theory to include the IPM rotor’s primary and secondary reluctance paths and the non-homogeneous airgap of the rotor sculpt features. The shape and placement of the rotor features, derived from the analytical-based optimization process, show the improvement in torque average and torque ripple of the IPM machine at a fraction of computational effort. The analytical optimization results are validated with finite element analysis via an exhaustive search.

A computationally efficient design of interior permanent magnet (IPM) motor rotor features is investigated utilizing analytical methods. Over the broad operating range of IPM machines, interactions of MMF sources, permeances, and currents result in torque harmonics. The placement of traditional rotor features along with sculpt features are utilized to minimize torque ripple and maximize average torque. We extend the winding function theory to include the IPM rotor’s primary and secondary reluctance paths and the non-homogeneous airgap of the rotor sculpt features. A new analytical winding function model of the single-V IPM machine is introduced, which considers the sculpted rotor and how this model can be used in the design approach of machines. Results are validated with finite elements. Rotor feature trends are established and utilized to increase design intuition and reduce dependency upon the lengthy design of experiment optimization processes.

The automobile is a classic example of technology going full circle. Vehicle power sources, namely gasoline, electricity, and even hybrids, were first debated more than 120 years ago when more than 30% of vehicles operated on electricity. Pioneers like Thomas Edison and Ferdinand Porsche lauded the superiority of electrics in the late 1800s, with Porsche introducing the world's first hybrid around 1890. The debate has been dominated by the internal combustion engine since the early 20th century, when Karl Benz and Henry Ford both created methods to mass-produce more affordable petrol-based vehicles.