I-Corps: Bearingless Electric Motors for Industrial Compressor Systems

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

The broader impact/commercial potential of this I-Corps project is the development of new technology that produces completely integrated electric machines. These machines will leverage geometry not readily manufactured with conventional machining to support 3-dimensional flux paths and actuate across all six degrees of freedom. This project's bearingless technology can unlock customer gains through enhanced system sensing capability to enable predictive maintenance and decreased noise, vibration, and harshness. The value proposition of bearingless technology is particularly strong for turbomachinery applications in wastewater aeration, waste heat recovery, automotive turbocharges, and thermal grid storage. By eliminating bearings, the proposed technology can increase the mean time between failure of motor systems. Through increased system reliability and lifetime, this technology can accelerate deployment of highly efficient, sustainable, and intelligent infrastructure solutions for the benefit of society. This I-Corps project is based on the development of new bearingless electric motor generator technology that provides the benefits of magnetic levitation while solving the challenges associated with magnetic bearings. The mechanical bearings used to support the shaft of today's electric motors and generators are a source of major pain for integrators, owners, and operators of electric machines. These pain points primarily come in the form of low system reliability and high total cost of ownership. While magnetic bearing manufacturers have attempted to solve these pain points by magnetically levitating the shaft (thereby eliminating mechanical bearings from motor/generators), this solution has seen limited market acceptance due to increased capital cost, lengthy timelines for new product commissioning, and integration challenges. This project's bearingless motor technology integrates the functionality of a magnetic bearing into the existing hardware of an electric motor/generator. While conventional electric motor/generators use stator winding current to control electromagnetic torque on their rotor, this bearingless motor/generators additionally use stator current to control electromagnetic forces on the rotor that make the motor act as if it were also a magnetic bearing. This technology is employed by unlocking the large radial electromagnetic pressure that is present in today's electric motor/generators but is canceled by deliberate design symmetry. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.