An Electric Power Generation System for Launch Vehicles

Launch vehicles that use electric actuators for thrust vector or flight control require a safe, reliable and lightweight source of electrical power. Honeywell, working with NASA Glenn Research Center and Lockheed Martin Space Systems, has developed and successfully tested a turbine-driven electric power generation system which meets these needs.

This Turbine Power Unit (TPU) uses hydrogen and oxygen propellants which react catalytically to drive a shaft-speed turboalternator mounted on foil bearings. A high-reactance permanent-magnet machine (HRPMM) was selected for this application. The power conditioning and control electronics can be located within the TPU housing and the hydrogen fuel can be used to pressurize the bearings and electronics and to regeneratively cool the machine.

A brassboard unit incorporating many of these features was successfully tested at output power levels from 0 to 138 kilowatts (kW). The 270 Vdc system was designed to meet the electromagnetic compliance requirements of MIL-STD-461E and the power quality requirements of MIL-STD-704E. Testing included continuous operation at loads up to 80 kW, load transient tests to verify power quality during steps of up to 120 kW at 300 amps/msec, and restart tests with shutdown intervals ranging from a few milliseconds up to 8 minutes. Testing culminated with a successful flight simulation test.