NASA SBIR 2003 Solicitation


PROPOSAL NUMBER: 03- II F1.01-8237
SUBTOPIC TITLE: Process and Human Factors Engineering Technologies
PROPOSAL TITLE: Three Phase Resonant DC Power Converter for Ion Thrusters

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Geoff Drummond
200 Commerce, Unit F
Fort Collins, CO 80524-2746
U.S. Citizen or Legal Resident: Yes

Our phase 1 study has revealed many significant benefits of a new class of DC-to-DC power converters with performance that cannot be matched by current flight power systems.
The goal of low stored energy has been demonstrated while producing a record-breaking efficiency of 95.5%. This new converter claims this remarkable accomplishment not at just one full power point but at two distinct points. The converter was able to delivery its full rated power of 1kW at 2850V and 5000V load voltages without any physical adjusts.
This new converter demonstrated low arc energy and rapid recovery response while powering NEXIS like sub-scale ion optics at Colorado State University. The 1kW prototype's stored energy was less than 1.9mj at 5000Voutput and less than 700?j at 2850V output.
In phase 2 we will integrate this new technology into a computerized ion thruster test system capable of delivering 24kW screen power. The planned test system will serve to gain confidence with the new topology and to initiate power system designers to an exciting new technology.

As a result of our phase 1 study we have implemented this new converter idea into our new line of low power traveling wave tube test systems. We sell the test systems to both NASA and non-NASA customers.
We expect to capture the manufacturing market for ion engine ground based test systems as well. As future flight power systems switch to this new topology there will be a need to supply equivalent commercial test equipment to both universities and flight system suppliers. There are many advantages of the new topology that are unknown to most engineers and physicists. As the capabilities of the new converter are better understood new applications will certainly be created. This design may come to be recognized for its power range capability or its extraordinary efficiency and not the low stored energy, as it is best known for now.

We are the world's leader in computerized traveling wave tube test stations. These test systems vary between average operating powers of 400 watts to 10,000 watts. We currently have a contract to provide two low power test systems to NASA's Glenn Research division. These are new systems, which contain the three-phase resonant circuit described in this proposal. The results of our phase 1 study prompted us to utilize this new design as soon as possible.
In addition to being the leader in TWT test stations we also would like to claim complete patronage from all users of ion thruster test equipment. It is anticipated that the new converter will quickly find use in many flight power systems. It is most desirable to perform ground testing with equipment similar to flight power systems. To that end we hope to capture the bulk of all ground test system equipment manufacture.