Capacitor Pulse Forming Network with Multiple Pulse Inductors

• US 20060290399A1
• Filed: 06/19/2006
• Published: 12/28/2006
• Est. Priority Date: 02/04/2004
• Status: Active Grant

• Current Assignee: General Atomics, Inc.
• Original Assignee: General Atomics, Inc.
• Inventors: MacDougall, Frederick W., Staines, Geoffrey W.
• Granted Patent: US 7,514,820 B2
• Time in Patent Office: Days
• US Class Current: 327/181
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/46 Accumulators structurally combined with charging apparatus circuits for charging H02J7/00
• CPC Class Codes: H02J 1/00 Circuit arrangements for dc mains or dc distribution networks
• CPC Class Codes: H03K 3/00 Circuits for generating electric pulses; Monostable, bistable or multistable circuits H03K4/00 takes precedence; for digital function generators in computers G06F1/02
• CPC Class Codes: H03K 3/53 by the use of an energy-accumulating element discharged through the load by a switching device controlled by an external signal and not incorporating positive feedback H03K3/335 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Capacitor based pulse forming networks and methods are provided which require fewer inductors are that pulsed more frequently to provide a smaller, lower mass, and lower inductance pulse forming network having better pulse shaping characteristics than conventional pulse forming networks. In one implementation, the invention can be characterized as a capacitor based pulse forming network comprising a plurality of inductors adapted to be coupled to a load, a plurality of capacitor units, and a plurality of switches. Each switch couples a respective capacitor unit to a respective inductor, wherein multiple capacitor units are coupled to each inductor by separate switches. The plurality of switches are adapted to non-simultaneously discharge at least some of the multiple capacitor units to provide non-simultaneous pulses through a given inductor to the load and not through other inductors. The non-simultaneous pulses form at least a portion of an output pulse waveform to the load.

Claims

1. A capacitor based pulse forming network comprising:

a plurality of inductors adapted to be coupled to a load;

a plurality of capacitor units;

a plurality of switches, each switch coupling a respective capacitor unit to a respective inductor, wherein multiple capacitor units are coupled to each inductor by separate switches; and

the plurality of switches are adapted to non-simultaneously discharge at least some of the multiple capacitor units to provide non-simultaneous pulses through a given inductor to the load and not through other inductors;

wherein the non-simultaneous pulses form at least a portion of an output pulse waveform to the load.

2. The network of claim 1 wherein the plurality of switches are adapted to simultaneously discharge others of the multiple capacitor units to provide simultaneous pulses through the given inductor to the load and not through the other inductors.

3. The network of claim 1 wherein a first switch is adapted to discharge one of the multiple capacitor units coupled to one inductor at substantially the same time as a second switch is adapted to discharge one of the multiple capacitor units coupled to another inductor.

4. The network of claim 1 further comprising:

a charging circuit coupled to each capacitor unit.

5. The network of claim 1 further comprising:

a timing controller coupled to each switch, the timing controller adapted to output a signal at an appropriate time to cause each switch to discharge a respective capacitor unit.

6. The network of claim 1 further comprising:

an anti-reversing diode coupled to each inductor, the anti-reversing diode coupled to a given inductor for limiting voltage reversal across discharged capacitor units.

7. The network of claim 1 wherein the non-simultaneous pulses through the given inductor do not overlap in time with each other.

8. The network of claim 1 wherein a portion of at least two of the non-simultaneous pulses through the given inductor overlap in time with each other.

9. The network of claim 1 wherein the non-simultaneous pulses through the given inductor are non-simultaneous with pulses through the other inductors.

10. The network of claim 1 wherein plurality of switches are adapted to sequentially discharge the plurality of capacitor units.

11. The network of claim 1 wherein the plurality of switches are adapted to discharge the last capacitor units in a discharging sequence at a successively higher frequency to produce the last pulses of a pulse sequence, such that each of the last pulses resonates at a higher frequency odd harmonic relative to a preceding pulse, such that sum of the last pulses substantially comprises a square waveform, wherein resulting a faster shut off time for the output pulse waveform.

12. The network of claim 1 further comprising an anti-reversing diode coupled between each switch and its respective capacitor.

13. The network of claim 1 wherein groups of the multiple capacitor units coupled by a respective switch to a respective inductor each comprise one of a plurality of energy storage modules.

14. The network of claim 13 wherein the plurality of switches are adapted to:

sequentially discharge a first capacitor unit of each energy storage module over time to provide a first pulse through each inductor to the load and not through inductors of other energy storage modules; and

sequentially discharge, after beginning the sequential discharge of the first capacitor unit of each energy storage module, a second capacitor unit of each energy storage module over time to provide a second pulse through each inductor to the load and not through the inductors of the other energy storage modules.

15. The network of claim 13 wherein the plurality of switches are adapted to:

sequentially discharge a first capacitor unit of each energy storage module over time to provide a first pulse through each inductor to the load and not through inductors of other energy storage modules; and

sequentially discharge, after beginning the discharge of the first capacitor unit of the last sequential energy storage module, a subsequent capacitor unit of each energy storage module over time to provide a subsequent pulse through each inductor to the load and not through the inductors of the other energy storage modules, wherein the subsequent pulse does not overlap in time with the first pulse of each energy storage module.

16. The network of claim 15 wherein the plurality of switches are adapted to:

repeat the sequential discharge of additional subsequent capacitor units to provide additional subsequent pulses through each inductor to the load until all of the plurality of capacitor units have been discharged.

17. The network of claim 15 wherein the plurality of switches are further adapted to:

sequentially discharge a last capacitor unit of a given energy storage module at a higher frequency such that a last pulse of the last capacitor unit resonates at a higher frequency odd harmonic relative to a last pulse of a sequentially preceding last capacitor unit of a sequentially preceding energy storage module, wherein causing a faster shut off time for the output pulse waveform.

18. The network of claim 13 wherein the plurality of switches are adapted to:

discharge one of the multiple capacitor units coupled to a given inductor; and

discharge another one of the multiple capacitor units coupled to the given inductor after a start of the discharging of the one of the multiple capacitor units and before a voltage of the one of the multiple capacitor units reaches zero.

19. The network of claim 13 wherein the plurality of switches are adapted to:

discharge one of the multiple capacitor units coupled to a given inductor; and

discharge another one of the multiple capacitor units coupled to the given inductor after a voltage of the one of the multiple capacitor units reaches zero.

20. The network of claim 13 wherein the load is a variable impedance load and the plurality of capacitor units are adapted to be charged to a voltage at a polarity, the network further comprising:

a shunt capacitor unit adapted to be charged to a voltage at an opposite polarity of the plurality of capacitor units; and

a shunt switch adapted to couple the shunt capacitor unit to the variable impedance load,

wherein the shunt switch is adapted to switch the shunt capacitor unit to the variable impedance load to absorb excess energy in the variable impedance load from the discharging of the plurality of capacitor units.

21. The network of claim 20 wherein the shunt capacitor unit comprises one of the plurality of capacitor units.

22. The network of claim 20 wherein the shunt capacitor is not one of the plurality of capacitor units.

23. The network of claim 13 wherein the load is a variable impedance load, the network further comprising:

at least one shunt switch adapted to couple at least one capacitor unit of at least one of the plurality of energy storage modules to the variable impedance load, wherein the at least one capacitor unit is allowed to go through a voltage reversal after discharging through its respective inductor and be charged to an opposite polarity,

wherein the at least one shunt switch is adapted to switch the at least one capacitor unit to the variable impedance load to absorb excess energy in the variable impedance load from the discharging of the plurality of capacitor units.

24. The network of claim 1 wherein at least some of the plurality of capacitor units are charged to different voltage levels.

25. The network of claim 1 wherein at least one of the plurality of capacitor units adapted to be discharged in time near an end of the output pulse waveform are charged to a higher voltage level than ones of the plurality of capacitor units adapted to be discharged prior in time.

26. The network of claim 13 further comprising at least one additional energy storage module comprising, the additional energy storage module comprising:

at least one additional inductor adapted to be coupled to the load;

a plurality of additional capacitor units coupled to each of the at least one additional inductor;

a switch coupling the plurality of additional capacitor units to a respective additional inductor, each switch adapted to simultaneously discharge the plurality of additional capacitor units to provide an additional pulse through the respective additional inductor to the load;

wherein the additional pulse forms at least a portion of the output pulse waveform to the load.

27. The network of claim 26 wherein the at least one additional energy storage module is adapted to be discharged prior to discharging of the plurality of capacitor units.

28. A method for providing a pulse waveform to a load comprising:

charging a plurality of capacitor units, wherein multiple capacitor units are coupled to each of a plurality of inductors, each inductor coupled to the load; and

non-simultaneously discharging at least some of the multiple capacitor units to provide non-simultaneous pulses through a given inductor to the load and not through other inductors;

wherein the non-simultaneous pulses form at least a portion of the pulse waveform.

29. The method of claim 28 further comprising:

simultaneously discharging others of the multiple capacitor units to provide simultaneous pulses through the given inductor to the load and not through the other inductors.

30. The method of claim 28 further comprising:

discharging one of the multiple capacitor units coupled to one inductor at substantially the same time as discharging one of the multiple capacitor units coupled to another inductor.

31. The method of claim 28 further comprising:

receiving timing signals at appropriate times to trigger the non-simultaneous discharging.

32. The method of claim 28 further comprising:

limiting voltage reversal across discharged capacitor units.

33. The method of claim 28 wherein the non-simultaneous pulses through the given inductor do not overlap in time with each other.

34. The method of claim 28 wherein a portion of at least two of the non-simultaneous pulses through the given inductor overlap in time with each other.

35. The method of claim 28 wherein the non-simultaneous pulses through the given inductor are non-simultaneous with pulses through the other inductors.

36. The method of claim 28 further comprising:

sequentially discharging the plurality of capacitor units.

37. The method of claim 28 wherein the non-simultaneous discharging step comprises:

sequentially discharging the multiple capacitor units to provide sequential pulses through the given inductor to the load and not through other inductors.

38. The method of claim 28 further comprising:

discharging the last capacitor units in a discharging sequence at a successively higher frequency to produce the last pulses of a pulse sequence, such that each of the last pulses resonates at a higher frequency odd harmonic relative to a preceding pulse, such that sum of the last pulses substantially comprises a square waveform, wherein resulting a faster shut off time for the output pulse waveform.

39. The method of claim 28 wherein the non-simultaneously discharging step comprises:

non-simultaneously closing respective switches, each switch coupling each of the multiple capacitor units to the given inductor.

40. The method of claim 28 further comprising:

limiting voltage reversal across the respective switches.

41. The method of claim 28 wherein groups of the multiple capacitor units coupled to a respective inductor each comprise one of a plurality of energy storage modules.

42. The method of claim 41 further comprising:

sequentially discharging a first capacitor unit of each energy storage module over time to provide a first pulse through each inductor to the load and not through inductors of other energy storage modules; and

sequentially discharging, after beginning the sequential discharging of the first capacitor unit of each energy storage module, a second capacitor unit of each energy storage module over time to provide a second pulse through each inductor to the load and not through the inductors of the other energy storage modules.

43. The method of claim 41 further comprising:

sequentially discharging a first capacitor unit of each energy storage module over time to provide a first pulse through each inductor to the load and not through inductors of other energy storage modules; and

sequentially discharging, after beginning the discharging of the first capacitor unit of the last sequential energy storage module, a subsequent capacitor unit of each energy storage module over time to provide a subsequent pulse through each inductor to the load and not through the inductors of the other energy storage modules, wherein the subsequent pulse does not overlap in time with the first pulse of each energy storage module.

44. The method of claim 43 further comprising:

repeating the sequentially discharging the subsequent capacitor units for additional subsequent capacitor units to provide additional subsequent pulses through each inductor to the load until all of the plurality of capacitor units have been discharged.

45. The method of claim 43 further comprising:

sequentially discharging a last capacitor unit of a given energy storage module at a higher frequency such that a last pulse of the last capacitor unit resonates at a higher frequency odd harmonic relative to a last pulse of a sequentially preceding last capacitor unit of a sequentially preceding energy storage module, wherein causing a faster shut off time for the output pulse waveform.

46. The method of claim 41 further comprising:

discharging one of the multiple capacitor units coupled to a given inductor; and

discharging another one of the multiple capacitor units coupled to the given inductor after a start of the discharging of the one of the multiple capacitor units and before a voltage of the one of the multiple capacitor units reaches zero.

47. The method of claim 41 further comprising:

discharging one of the multiple capacitor units coupled to a given inductor; and

discharging another one of the multiple capacitor units coupled to the given inductor after a voltage of the one of the multiple capacitor units reaches zero.

48. The method of claim 41 wherein the load is a variable impedance load and the plurality of capacitor units are adapted to be charged to a voltage at a polarity, the method further comprising:

charging a shunt capacitor unit to a voltage at an opposite polarity of the plurality of capacitor units; and

coupling the shunt capacitor unit to the variable impedance load to absorb excess energy in the variable impedance load from the discharging of the plurality of capacitor units.

49. The method of claim 48 wherein the shunt capacitor unit comprises one of the plurality of capacitor units.

50. The network of claim 48 wherein the shunt capacitor is not one of the plurality of capacitor units.

51. The method of claim 41 wherein the load is a variable impedance load, the method further comprising:

allowing at least one capacitor unit of at least one of the plurality of energy storage modules to go through a voltage reversal after discharging through its respective inductor and to be charged to an opposite polarity,

coupling the at least one capacitor unit to the variable impedance load to absorb excess energy in the variable impedance load from the discharging of the plurality of capacitor units.

52. The method of claim 28 wherein the charging step comprises charging at least some of the plurality of capacitor units to different voltage levels.

53. The method of claim 28 wherein the charging step comprises charging at least one of the plurality of capacitor units adapted to be discharged in time near an end of the output pulse waveform to a higher voltage level than ones of the plurality of capacitor units adapted to be discharged prior in time.

54. The method of claim 41 further comprising:

providing at least one additional energy storage module comprising at least one additional inductor coupled to the load and a plurality of additional capacitor units coupled to each of the at least one additional inductor, wherein multiple capacitor units are coupled to each of a plurality of inductors;

charging the plurality of additional capacitor units;

simultaneously discharging the plurality of additional capacitor units coupled to a respective additional inductor to provide an additional pulse through the respective additional inductor to the load;

wherein the additional pulse form at least a portion of the output pulse waveform.

55. The method of claim 54 wherein the simultaneously discharging step occurs prior to the non-simultaneously discharging step.

56. The method of claim 28 further comprising:

discharging the plurality of capacitor units, the discharging step including the non-simultaneous discharging step; and

controlling a timing of the discharging of the capacitor units in order that the pulse waveform have a predetermined shape.

57. The method of claim 28 wherein the controlling the timing step further comprising:

adjusting the timing of the discharging while discharging in response a variable impedance of the load.

58. A capacitor based pulse forming network comprising:

means for charging a plurality of capacitor units, wherein multiple capacitor units are coupled to each of a plurality of inductors, each inductor coupled to the load; and

means for non-simultaneously discharging at least some of the multiple capacitor units to provide non-simultaneous pulses through a given inductor to the load and not through other inductors;

wherein the non-simultaneous pulses form at least a portion of the pulse waveform.