Development of a High-power Motor/Generator for the ARPA-E Hub-Less Flywheel

Recognizing the advantages of flywheels in rapid-response, high cycle-life applications, ARPA-E has funded Beacon Power to develop critical components for a low cost flying ring hub-less flywheel under the GRIDS program. The funded system will provide 100 kW for 1 hour for firming and smoothing of intermittent-renewable power generation. For this large, low-cost flywheel to be applicable to either Frequency Regulation, or Frequency Response applications, the motor/generator capability will need to be increased to over 400 kW. The permanent magnet motor/generator (PMMG) configuration proposed in the APRA-E project is based upon the use of bonded magnets (which give up a significant amount of remnant flux density (Br) in exchange for strain capability) together with a stator with no back-iron (and so no negative spring constant). The questions are: 1. Can some of this Br be regained with other bonded magnet materials and/or processes? 2. Can the bearing system be designed to accommodate the negative stiffness from adding back-iron? 3. Is the resulting stator size reasonable? and 4. Can the losses in the resulting high-power design be dissipated? Commercial Applications and Other Benefits: The new high-power motor/generator will make it possible to commercialize at least six major energy balancing applications at a cost equal to one-third the cost of our current Gen4 flywheel: Frequency Regulation and Frequency Response; Primary and Secondary Reserve, which is what Europe and parts of the rest of the world use to balance system frequency; Super Primary Response, a derivative of our core technology that can replace conventional spinning reserve for event contingencies; ramp mitigation for solar PV; load following and ramp mitigation for wind-diesel-storage hybrid applications; and micro grid stabilization. These applications cover a broad spectrum of commercial, governmental, industrial, institutional and military market segments in the U.S. and abroad. If this SBIR project is successful we will commercialize the device in all six application areas. This will greatly leverage the impact of the R & amp;D investment and maximize short and long-term economic impacts.