High Frequency, High Specific Power Electric Machines
Funded by the Grainger Foundation and NASA, efforts are being made to help advance state-of-the-art induction motor (IM) and permanent magnet synchronous motor (PMSM) technology by reducing machine size and weight. High frequency, high pole count designs are being explored to reduce/eliminate the use of ferromagnetic iron in the magnetic circuit, and addressing corresponding electromagnetic, thermal, and mechanical implications. Detailed analysis is being performed using analytical and numerical models which capture the multi-physics trades associated with this approach. The opportunity for increased power density using the high frequency, high pole design has been demonstrated for PMSMs, and effects of similar approach to IMs are currently being explored.
Air-core Superconducting Machine
This project is a multi-disciplinary effort to establish the feasibility of an order-of-magnitude increase in electric machine power density by employing a novel superconducting machine architecture. Superconducting field coils open up a new design space for electrical machines with significantly higher magneto-motive force capability than conventional coils. This capability can be used to eliminate ferromagnetic material in the machine, and deal with a significantly higher magnetic reluctance (e.g. 10X). With the iron and its saturation limit removed, designs with much higher air-gap flux density (5-10X current levels) can be generated. We plan to reduce risks related to what many consider ‘exotic’ superconducting technology by using available, mature superconductors, specifically Nb3Sn, and by leveraging cryogenic cooling solutions utilized in the health care industry. The proposed concept does introduce new challenges, though if successful it would eliminate the biggest roadblock towards electric propulsion.
Diagnosis of arcing in Retaining Rings in Synchronous Generators of Power Plant