High voltage pulsed power supply using solid state switches with droop compensation

• US 7,554,221 B2
• Filed: 03/07/2007
• Issued: 06/30/2009
• Est. Priority Date: 05/04/2004
• Status: Active Grant

• Current Assignee: Stangenes Industries, Inc.
• Original Assignee: Stangenes Industries, Inc.
• Inventors: Cassel, Richard L.
• Primary Examiner(s): Paladini; Albert W
• Assistant Examiner(s): RUTLAND WALLIS, MICHAEL
• Application Number:
  US11/683,270
• Publication Number:
  US 20070146092A1
• Time in Patent Office: 846 Days
• Field of Search: 307/106, 307/108
• US Class Current: 307/108
• 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: H03K 17/145 in field-effect transistor switches
• CPC Class Codes: H03K 17/284 in field effect transistor switches
• CPC Class Codes: H03K 3/57 the switching device being a semiconductor device

Abstract

Systems and methods for generating a high voltage pulse. A series of voltage cells are connected such that charging capacitors can be charged in parallel and discharged in series. Each cell includes a main switch and a return switch. When the main switches are turned on, the capacitors in the cells are in series and discharge. When the main switches are turned off and the return switches are turned on, the capacitors charge in parallel. One or more of the cells can be inactive without preventing a pulse from being generated. The amplitude, duration, rise time, and fall time can be controlled with the voltage cells. Each voltage cell may also includes a balance network to match the stray capacitance seen by each voltage cell. Droop compensation is also enabled.

Claims

1. A pulse generator that generates a voltage pulse that is applied to a load, the pulse generator comprising:

a plurality of first voltage cells, each voltage cell having a capacitor in series with a main switch such that all capacitors are connected in series when all main switches are on to generate a voltage pulse that is delivered to a load; and

a second voltage cell connected in series with the plurality of first voltage cells, the second voltage cell including;

a pair of capacitors in series with a second main switch;

at least a first diode arranged with the pair of capacitors such that the pair of capacitors charge in series when the main switch is off and discharge in parallel when the main switch is on; and

a ringing circuit that includes;

an inductor in series with the pair of capacitors; and

a ringing capacitor in parallel with the inductor, wherein the ringing capacitor charges to twice a value of the pair of capacitors and provides droop compensation to the voltage pulse.

2. A pulse generator as defined in claim 1, wherein the pair of capacitors are connected such that the pair of capacitors charge in series with the capacitors in the plurality of first voltage cells and discharge in parallel to the ringing circuit.

3. A pulse generator as defined in claim 1, wherein the plurality of first voltage cells each comprise a return switch.

4. A pulse generator as defined in claim 3, wherein a charging source provides a charging current that passes through each of the return switches to charge the capacitors in the plurality of first voltage cells.

5. A pulse generator as defined in claim 4, further comprising a diode string that provides a return path to the charging source for the charging current.

6. A pulse generator as defined in claim 1, wherein the second voltage cell further comprises a second diode between the pair of capacitors.

7. A pulse generator as defined in claim 1, the second voltage cell further comprising a second return switch.

8. A pulse generator as defined in claim 7, wherein control signals are used to turn the main switches and the return switches on or off in order to control a rise time or a fall time of the voltage pulse.

9. A pulse generator as defined in claim 1, wherein the ringing circuit provides smooth compensation by generating a half sine wave voltage output.

10. A pulse generator that generates a voltage pulse that is applied to a load, the pulse generator comprising:

a main switch;

a first capacitor in series with the main switch;

a second capacitor in series with the first capacitor;

a first diode connected between the first and second capacitor, wherein a charging current charges the first and second capacitor in series;

a ringing circuit connected to the first and second capacitor, the ringing circuit including;

a first inductor in series with the first and second capacitor; and

a third capacitor across the first and second capacitor; and

a plurality of diodes arranged with the first and second capacitor such that the first and second capacitor charge in series when the main switch is off and discharge in parallel when the main switch is on, wherein the ringing circuit generates a voltage that is twice the voltage of the discharging first and second capacitor and that provides smooth droop compensation to a voltage pulse.

11. A pulse generator as defined in claim 10, further comprising a return switch, wherein the charging current passes from a charging source through the return switch and charges a capacitor of another voltage cell.

12. A pulse generator as defined in claim 11, further comprising a first switch drive that controls the main switch and a second switch drive that controls the return switch.

13. A pulse generator as defined in claim 10, further comprising a plurality of voltage cells connected in series with the first and second capacitor, wherein the plurality of voltage cells each have a capacitor that receives a charging current through a return switch of another voltage cell.

14. A pulse generator as defined in claim 10, wherein the main switch and the return switch are controlled with control signals in a manner that permits a rise time of the voltage and a fall time of the voltage pulse to be controlled.

15. A pulse generator as defined in claim 14, wherein the return switch is turned on to increase a fall time of the voltage pulse by allowing charge to dissipate through the return switch.

16. A pulse generator as defined in claim 14, wherein the main switch is powered thorough an auxiliary diode string and wherein the control signals are optically coupled to the main switch and to the return switch.

17. A voltage pulse generator for generating a voltage pulse, the voltage pulse generator comprising:

a plurality of first voltage cells each having a main switch and a capacitor in series such that each main switch and each capacitor is in series with other main switches and other capacitors in other first voltage cells when the main switches are on, wherein the capacitors are isolated from each other until the main switches are turned on such that the serially connected capacitors deliver a voltage pulse without using transformers;

a diode string connected with the plurality of first voltage cells;

a plurality of first return switches included in the plurality of first voltage cells, wherein a charging current passes through the first return switches and the diode string such that the capacitors in the plurality of first voltage cells are charged in parallel; and

a second voltage cell comprising;

a second main switch;

at least a pair of capacitors in series with the main switch and connected using a plurality of diodes such that the pair of capacitors charge in series and such that the pair of capacitors charge in parallel with respect to the capacitors in the plurality of first voltage cells, wherein the plurality of diodes are arranged such that the pair of capacitors discharge in parallel when the second main switch is on; and

a ringing circuit connected to the pair of capacitors, wherein the ringing circuit rings when the pair of capacitors discharge to generate a half sine wave voltage that provides droop compensation to the voltage pulse, the ringing circuit including an inductor in series with the pair of capacitors and a third capacitor across the pair of capacitors.

18. A voltage pulse generator as defined in claim 17, further comprising ringing diodes that are connected between the ringing circuit and the pair of capacitors such that energy in the inductor or in the third capacitor can discharge into the pair of capacitors when the main switch is turned off.