High voltage pulse generator

• US 20060139977A1
• Filed: 12/28/2004
• Published: 06/29/2006
• Est. Priority Date: 12/28/2004
• Status: Active Grant

• Current Assignee: Excelitas Technologies Corporation (Excelitas Technologies Holdings LLC)
• Original Assignee: Kaiser Systems, Inc.
• Inventors: Johns, David M., Oicles, Jeffrey Alan
• Granted Patent: US 7,209,373 B2
• Time in Patent Office: Days
• US Class Current: 363/71
• CPC Class Codes: H02M 1/009 having two or more independently controlled outputs for DC-DC converter with intermediate AC H02M3/33561
• CPC Class Codes: H02M 3/07 using capacitors charged and discharged alternately by semiconductor devices with control electrode , e.g. charge pumps
• CPC Class Codes: H02M 3/285 Single converters with a plurality of output stages connected in parallel parallel operation of a plurality of converters in dc distribution networks H02J1/10
• CPC Class Codes: H02M 3/3376 with automatic control of output voltage or current
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A high voltage pulse generator utilizes an even number of Marx cells using L-C inversion topology. Each Marx cell is associated with an individual inverter transformer having a primary winding connected to the output of an ac power supply such as a series resonant inverter. The secondary of each inverter transformer is half-wave rectified to charge the energy storage capacitors in each Marx cell. A distributed voltage sensing scheme can be provided for accurate feedback to the inverter'"'"'s controller. An inductive element can be used to achieve a magnetic diode effect in the L-C inversion circuit to reduce component stress and improve efficiency. A transformer-coupled floating gate drive circuit is used to provide local power conditioning and trigger timing for discharge of the energy storage capacitors.

Claims

1. A high voltage pulse generator comprising:

a power supply having an ac output;

an even number of capacitor charging circuits, each of the even number of capacitor charging circuits comprising an LC inversion Marx generator having two or more capacitors and a switch to control charging and discharging of the capacitors; and

a plurality of cell inverter transformers, each of the plurality of cell inverter transformers comprising a primary winding and a secondary winding to supply ac power to each of the even number of capacitor charging circuits, each of the plurality of cell inverter transformers having its primary winding connected across the ac output of the power supply, each of the plurality of cell inverter transformers having its secondary winding connected exclusively to at least one of the two or more capacitors in one of the even number of capacitor charging circuits by a means for converting the ac power to dc power, each of the plurality of cell inverter transformers and associated means for converting the ac power to dc power comprising a circuit to supply the ac output of the power supply to the two or more capacitors in half of the even number of capacitor charging circuits with inverted phase from the ac output of the power supply to the two or more capacitors in the remaining half of the even number of capacitor charging circuits.

2. The high voltage pulse generator of claim 1 further comprising a feedback circuit for sensing the voltage across the two or more capacitors in each of the LC inversion Marx generators and for outputting a signal proportional to the sensed voltage to the power supply.

3. The high voltage pulse generator of claim 1 further comprising two or more arrays, each of the two or more arrays comprising an equal number of the LC inversion Marx generators, and a feedback circuit for sensing the summed voltages across the two or more capacitors in each of the equal number of the LC inversion Marx generators in each of the arrays and for outputting a signal proportional to the sensed voltages to the power supply.

4. A high voltage pulse generator comprising:

a power supply having an ac output;

an even number of capacitor charging circuits, each of the even number of capacitor charging circuits comprising an LC inversion Marx generator having two or more capacitors and a switch to control charging and discharging of the capacitors;

a plurality of cell inverter transformers, each of the plurality of cell inverter transformers comprising a primary winding and a secondary winding to supply ac power to each of the even number of capacitor charging circuits, each of the plurality of cell inverter transformers having its primary winding connected across the ac output of the power supply, each of the plurality of cell inverter transformers having its secondary winding connected exclusively to at least one of the two or more capacitors in one of the even number of capacitor charging circuits by a means for converting the ac power to dc power, each of the plurality of cell inverter transformers and associated means for converting the ac power to dc power comprising a circuit to supply the ac output of the power supply to the two or more capacitors in half of the even number of capacitor charging circuits with inverted phase from the ac output of the power supply to the two or more capacitors in the remaining half of the even number of capacitor charging circuits;

a pulse generating circuit for generating a train of periodic normal pulses except when a trigger event causes the pulse generating circuit to generate a trigger pulse; and

a pulse processing circuit having a pulse processing circuit input for receiving the periodic normal pulses and trigger pulses from the pulse generating circuit, the pulse processing circuit generating a close switch output to close the switch in each of the LC inversion Marx generators when a trigger pulse is received.

5. The high voltage pulse generator of claim 4 wherein the pulse processing circuit further comprises a pulse processing circuit power supply having an input from the pulse processing circuit input and an output for generating the close switch output of the pulse processing circuit whereby the periodic normal pulses provide a sources of power to the pulse processing circuit power supply.

6. The high voltage pulse generator of claim 4 further comprising a feedback circuit for sensing the voltage across each of the two or more capacitors in each of the LC inversion Marx generators and for outputting a signal proportional to the sensed voltage to the resonant series inverter.

7. The high voltage pulse generator of claim 4 further comprising two or more arrays, each of the two or more arrays comprising an equal number of the LC inversion Marx generators, and a feedback circuit for sensing the summed voltages across the two or more capacitors in each of the equal number of the LC inversion Marx generators in each of the arrays and for outputting a signal proportional to the sensed voltages to the power supply.

8. The high voltage pulse generator of claim 4 further comprising a saturable reactor connected in series with the switch in at least one of the LC inversion Marx generators.

9. A high voltage pulse generator comprising:

a power supply having an ac output;

an even number of capacitor charging circuits, each of the even number of capacitor charging circuits comprising an LC inversion Marx generator having two or more capacitors and a switch to control charging and discharging of the two or more capacitors, the two or more capacitors in all capacitor charging circuits connected in series to form a stacked charging circuit;

a plurality of cell inverter transformers, each of the plurality of cell inverter transformers comprising a primary winding and a secondary winding to supply ac power to each of the even number of capacitor charging circuits, each of the plurality of cell inverter transformers having its primary winding connected across the ac output of the power supply, each of the plurality of cell inverter transformers having its secondary winding connected exclusively to at least one of the two or more capacitors in one of the even number of capacitor charging circuits by a means for converting the ac power to dc power, each of the plurality of cell inverter transformers and associated means for converting the ac power to dc power comprising a circuit to supply the ac output of the power supply to the two or more capacitors in half of the even number of capacitor charging circuits with inverted phase from the ac output of the power supply to the two or more capacitors in the remaining half of the even number of capacitor charging circuits;

a pulse generating circuit for generating a train of periodic normal pulses except when a trigger event causes the pulse generating circuit to generate a trigger pulse;

a pulse processing circuit having a pulse processing circuit input for receiving the periodic normal pulses and trigger pulses from the pulse generating circuit, the pulse processing circuit generating a close switch output to close the switch in each of the LC inversion Marx generators when a trigger pulse is received; and

a power modulator having an output connected to a pulsed load, the stacked charging circuit connected directly to the power modulator to provide a high voltage pulse to the pulsed load.

10. The high voltage pulse generator of claim 9 wherein the power modulator comprises a magnetic pulse compression circuit.

11. The high voltage pulse generator of claim 9 wherein the pulse processing circuit further comprises a pulse processing circuit power supply having an input from the pulse processing circuit input and an output for generating the close switch output of the pulse processing circuit whereby the periodic normal pulses provide a source of power to the pulse processing circuit power supply.

12. The high voltage pulse generator of claim 9 further comprising a feedback circuit for sensing the voltage across each of the two or more capacitors in each of the LC inversion Marx generators and for outputting a signal proportional to the sensed voltage to the power supply.

13. The high voltage pulse generator of claim 9 comprising two or more arrays, each of the two or more arrays comprising an equal number of the LC inversion Marx generators, and a feedback circuit for sensing the summed voltages across the two or more capacitors in each of the equal number of the LC inversion Marx generators in each of the arrays and for outputting a signal proportional to the sensed voltages to the power supply.

14. The high voltage pulse generator of claim 9 further comprising a saturable reactor connected in series with the switch in at least one of the LC inversion Marx generators.

15. A method of generating a high voltage pulse comprising the steps of:

connecting the primary winding of each of a plurality of cell inverter transformers to the ac output of a power supply;

connecting the seconding winding of each of the plurality of cell inverter transformers to a rectifier means to convert the ac output of the power supply into dc power; and

connecting each of the rectifier means to at least one of the capacitors in each of an even number of LC inversion Marx generators to provide a means for charging the capacitors, each of the even number of LC inversion Marx generators having a switch to control charging and discharging of the capacitors, half of the plurality of cell inverter transformers having their primary windings arranged in inverted phase to the ac output of the power supply from the remaining plurality of cell inverter transformers to charge the capacitors in half of the even number of LC inversion Marx generators in each half cycle of the ac output of the power supply.

16. The method of claim 15 further comprising the steps of sensing the voltage across each of the capacitors in the even number of LC inversion Marx generators, and inputting to the power supply a signal proportional to the sensed voltage across each of the capacitors.

17. The method of claim 15 further comprising the steps of dividing the even number of LC inversion Marx generators into two or more arrays, each of the two or more arrays having an equal number of the LC inversion Marx generators;

sensing the summed voltages across each of the capacitors in the equal number of the LC inversion Marx generators in each of the arrays; and

inputting to the power supply a signal proportional to the sensed summed voltages.

18. The method of claim 15 further comprising the steps of generating a train of periodic normal pulses except when a trigger event occurs, and generating a trigger pulse when the trigger event occurs.

19. The method of claim 18 further comprising the step of closing the switch in each of the even number of LC inversion Marx generators when the trigger pulse is generated.

20. The method of claim 19 further comprising the step of using the train of period normal pulses to supply power for closing the switch in each of the even number of LC inversion Marx generators when the trigger pulse is generated.

21. The method of claim 15 further comprising the step of inserting a saturable reactor in series with the switch in at least one of the even number of LC inversion Marx generators.

22. The method of claim 19 further comprising the steps of stacking the even number of LC inversion Marx generators so that the capacitors in the even number of LC inversion Marx generators are connected in series, and connecting the series connected capacitors directly to a power modulator to supply a high voltage pulse to a pulsed load.