Accession Number:

ADA626654

Title:

Development, Vibration, and Thermal Characterization of a Steady Operating Pulsed Power System for FRC Thrusters

Descriptive Note:

Technical paper Apr-Jun 2015

Corporate Author:

AIR FORCE RESEARCH LAB EDWARDS AFB CA AEROSPACE SYSTEMS DIRECTORATE

Report Date:

2015-04-01

Pagination or Media Count:

34.0

Abstract:

A steady operating pulsed power system has been developed for advanced electromagnetic propulsion systems. This PPU has been developed for advanced electric propulsion systems which use inductive loads to provided electromagnetic forces which accelerate a plasma. The Electrodeless Lorentz Force ELF Thruster is a revolutionary electric propulsion thruster and power processing system that will allow a significant decrease in system mass and increase lifetime over traditional 500-10000 W propulsion systems. The ELF employs a Rotating Magnetic Field RMF to produce large plasma currents inside a conical thruster creating a field-reversed configuration FRC plasmoid that is magnetically isolated from the thruster walls. The PPU consists of a pulse charging circuit which uses an inductor to pulse charge a 100 VDC bus to high voltage. This in turn charges a high-Q capacitor. Connected in series with the thruster antenna, the resonant RLC circuit oscillates at high frequency with a vacuum Q. The high speed IGBT array is switched, discharging the circuit with a rise time of less than 400 ns. When a neutral gas is present, two out-of-phase ringing RF circuits create a net RMF which fully ionizes and inductively loads the antenna circuit. The net effective resistance and inductive coupling decreases the plasma and circuit Q leading to energy coupling into the plasma. The primary challenge in these systems is that they operate with peak power in the MW regime, though average powers in the kW. Onboard, real-time over-voltage, over-current, and integrated switch health monitoring circuitry protect the PPU from any anticipated circuit, plasma, or spacecraft radiation fault modes. In addition, significant advances in high-speed, inductive switch gate drive, input filtering, and power regulation are be utilized to aid switch stability and increase efficiency. This PPU system has demonstrated greater than 1E9 discharges and steady thermal operation in vacuum.

Subject Categories:

  • Mechanics
  • Thermodynamics
  • Electric and Ion Propulsion

Distribution Statement:

APPROVED FOR PUBLIC RELEASE