Aerojet Rocketdyne, Inc.

Brian A Koch

Alexandr L Kristalinski

Michael Madigan

A circuit for igniting and sustaining an electron discharge includes an ignitor circuit. The ignitor circuit includes a high voltage transformer and a switch connected in series between a primary of the transformer and a DC source return. The switch is configured to receive a driving signal. A reset circuit is connected in parallel to the primary of the high voltage transformer. A first rectifier is connected in series between a secondary of the high voltage transformer and a keeper. A terminal of the secondary of transformer is connected to a cathode. The circuit for igniting and sustaining the electron discharge also includes a sustaining circuit having a current source with a return connected to a cathode and a second rectifier connected in series between the current source and the keeper.

Electric propulsion system including heaterless dispenser cathode

A circuit comprising: first and second transistors connected in series; a third transistor (TT) comprising a source connected to a source of the second transistor (ST), a gate connected to a gate of ST, and a drain connected to a gate of the first transistor (FT); and a gate driver circuit connected to the gates of FT, ST and TT and configured to provide (i) a first drive signal to the gate of FT to cause FT to transition between an on state and an off state and (ii) a second drive signal to the gates of ST and TT to cause ST and TT to transition between on states and off states. The TT is configured to prevent a shoot-through condition in the circuit by pulling the first drive signal down to a level of the source of the ST when the ST is in the on state.

Shoot-through protection circuit

A spacecraft propulsion system including a first thruster system including a first power processing unit connected to a first thruster string via a crossover switching unit and connected to a second thruster string via the crossover switching unit. A second thruster system including a second power processing unit connected to the second thruster string via the crossover switching unit and to the first thruster string via the crossover switching unit. A controller is connected to each of the first power processing unit, the second power processing unit, and the crossover switching unit.

Satellite including crossover power processing units for electric thrusters

A circuit for igniting and sustaining an electron discharge includes an ignitor circuit. The igniter circuit includes a high voltage transformer and a switch connected in series between a primary of the transformer and a DC source return. The switch is configured to receive a driving signal. A reset circuit is connected in parallel to the primary of the high voltage transformer. A first rectifier is connected in series between a secondary of the high voltage transformer and a keeper. A terminal of the secondary of transformer is connected to a cathode. The circuit for igniting and sustaining the electron discharge also includes a sustaining circuit having a current source with a return connected to a cathode and a second rectifier connected in series between the current source and the keeper.

A circuit () comprising: a first power source () supplying first current to a load () during a first Period of Time ('PoT'); a second power source () supplying a second current to the load during a second POT; a Unidirectional Current Valve ('UCV') in series with the first power source; a current detector () in series with the UCV (); and a switch () in parallel with a series combination of the current detector and UCV to bypass the UCV during the second PoT. The current detector determines whether the second period of time has commenced and whether the switch has closed.

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Sacramento, CA, United States of America

Brian A Koch