ZERO RARE-EARTH MAGNET INTEGRATED STARTER-GENERATOR DEVELOPMENT FOR MILITARY VEHICLE APPLICATIONS

The demand for increased export power generation and ground vehicle electrification are escalating trends due to the warfighter’s expanding mission requirements. Today’s low-voltage alternators used in some fielded ground vehicle’s power systems supply up to 650ADC, or 18kW. Future demand for vehicle export power generation is expected to reach and exceed 100kW. A majority of electric machines capable of meeting this level of power generation rely on rare-earth elements such as Neodymium (Nd), Samarium (Sm), Dysprosium (Dy) and Terbium (Tb). Due to diminished reserves in the United States, availability abroad and price volatility, continued use of rare-earth permanent magnet materials may not be viable. The expanding demand for vehicle power is on a trajectory which surpasses the U.S. ability to reliably harvest or procure rare-earth magnet materials. As such, electric machine topologies that utilize zero rare-earth magnet materials are being considered for ISG (integrated-starter-generator) applications. This paper investigates alternative permanent magnet materials and motor topologies for the design of an ISG capable of 100kW of output power and a continuous/peak torque of 1200Nm/1800Nm that do not include rare-earth elements. A comparative analysis detailing the zero rare-earth permanent magnet material selection process along with accompanied motor topology will be given.