Phase 1 STTR flywheel motor/alternator for hybrid electric vehicles. CRADA final report

Visual Computing Systems (VCS) and the Oak Ridge National Laboratory (ORNL) have teamed, through a Phase 1 Small Business Technology Transfer (STTR) grant from the US Department of Energy (DOE), to develop an advanced, low-cost motor/alternator drive system suitable for Flywheel Energy Storage (FES) applications. During Phase 1, system performance and design requirements were established, design concepts were generated, and preliminary motor/alternator designs were developed and analyzed. ORNL provided mechanical design and finite element collaboration and Lynx Motion Technology, a spin-off from VCS to commercialize their technology, constructed a proof-of-concept axial-gap permanent magnet motor/alternator that employed their Segmented Electromagnetic Array (SEMA) with a survivable design speed potential of 10,000 rpm. The VCS motor/alternator was successfully tested in ORNL`s Motor Test Tank using an ORNL inverter and ORNL control electronics. It was first operated as an unloaded motor to 6,000 rpm and driven as an unloaded generator to 6,000 rpm. Output from the generator was then connected to a resistance bank, which caused the loaded generator to decelerate to 3,860 rpm where data was collected. After about 4-1/2 minutes, the test was terminated because of an impact noise. Subsequent inspection and operation at low speeds did not reveal the source of the noise. Electrical performance of the motor was excellent, encouraging continued development of this technology. Phase 2 efforts will focus on further design development and optimization, manufacturing development and prototype construction, testing, and evaluation