Simulating a 1-kW arcjet thruster using a nonlinear active load

Arcjet thrusters are known to have distinctly nonlinear electrical characteristics with negative incremental resistance throughout their normal operating region. The 1-kW arcjet simulator proposed here is an electronic load bank which accurately mimics these characteristics statically and dynamically up to 40 kHz. A power-processing unit (PPU) was tested using a resistive load bank, the simulator, and a 1-kW arcjet. The simulator was found to be an accurate stand-in for the arcjet during system transient testing, while the resistive load was not. The simulator uses resistors and insulated-gate bipolar transistors to dissipate the PPU output power; a nonlinear feedback is applied to produce the desired v-i characteristics. This feedback is analyzed dynamically. This arcjet simulator allows the development of a new PPU design to a higher level of confidence before beginning testing at an arcjet facility.