NASA SBIR 2005 Solicitation


SUBTOPIC TITLE:Spacecraft Propulsion
PROPOSAL TITLE:Wide Output Range Power Processing Unit for Electric Propulsion

SMALL BUSINESS CONCERN (Firm Name, Mail Address, City/State/Zip, Phone)
Colorado Power Electronics, Inc.
120 Commerce Drive, Unit 3
Fort Collins ,CO 80524 - 4731
(970) 482 - 0191

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Geoffrey Neal Drummond
120 Commerce Drive, Unit 3
Fort Collins, CO  80524 -4731
(970) 482 - 0191

Hall thrusters can be operated over a wide range of specific impulse while maintaining high efficiency. However S/C power system constraints on electric propulsion systems often force a choice of maximum power operation over a narrow range of specific impulse and thrust. Most spacecraft users would desire a continuous selection of thrust and specific impulse at maximum power when possible, but power supply systems currently do not exist with this level of functionality. To provide continuous Hall thruster adjustment, a power supply must be wide ranging in voltage, current, and power. In addition, the power supply system must be lightweight and efficient. The proposed work addresses these needs through a three-phase resonant power conversion strategy combined with novel frequency selective output-stage circuitry that will allow greater than 8:1 output voltage adjustment at power levels up to and beyond 100-kW. Three-phase resonant power converters utilize filter components with lower mass and size relative to single-phase converters, and demonstrated efficiencies are greater than 97%. Additionally, resonant converters operate at higher frequency, which results in extended stability when used in dynamic load situations imposed by Hall thrusters. The proposed Phase I program will develop a prototype power supply and demonstrate its functionality.

The primary market for this technology is for space power conversion were low cost power processing is required. Present technology includes PPU designs with real costs that are much greater than $200k per kilo watt of power. The previous designs show poor reuse of modules and power hardware. Additionally the present PPU designs fail to provide a base structure that can accommodate growth and change in module power. The new design will use lower loss elements to simplify fabrication and reduce cost. The proposed "next generation design" will accommodate the addition and subtraction of modules while conserving PPU mass. The extraordinary wide output impedance range of the converter will increase utility by allowing one PPU design to power several different thruster types. A successfully completed Phase II program will result in Phase III programs where brass-board PPUs will be provided for NASA missions utilizing NSTAR and possibly NEXT thrusters. A Phase III brass-board program will be used to flush out all remaining issues related to 3PRC flight use. Once complete, CPE and its sub-contractor Aerojet will be set to fabricate high quality flight hardware at the minimum cost.

Non-NASA uses for the proposed idea are commercial applications for space power where low cost and high efficiency are desired. Again the same advantages apply here. The most notable being the wide utility and range. This wide range converter will reduce the number of different model types required to satisfy current and future EP thruster needs. One immediate non-NASA application is for Aerojet thrusters that are being developed for geosynchronous satellite use.

Commercial non-flight applications include laboratory bench power supplies. A path to high volume sales may be achieved by using the converters refined in this SBIR for general purpose scientific equipment.

NASA's technology taxonomy has been developed by the SBIR-STTR program to disseminate awareness of proposed and awarded R/R&D in the agency. It is a listing of over 100 technologies, sorted into broad categories, of interest to NASA.

Electrostatic Thrusters
Power Management and Distribution

Form Printed on 09-19-05 13:12