PULSED POWER CIRCUITS USING HYBRID NON-LINEAR MAGNETIC MATERIALS AND INDUCTORS INCORPORATING THE SAME
20240039234 ยท 2024-02-01
Inventors
- Yuda Wang (San Diego, CA, US)
- Paul Christopher Melcher (El Cajon, CA, US)
- Changqi You (San Diego, CA, US)
Cpc classification
H01F21/08
ELECTRICITY
H03K3/45
ELECTRICITY
International classification
H03K3/45
ELECTRICITY
H01F21/08
ELECTRICITY
Abstract
A pulsed power circuit (30, 31, 32) including an inductor (55) having a hybrid core of a switch magnetic material arranged and selected to function as a magnetic switch a damping magnetic material arranged and selected to damp energy reflections without interfering with the switch magnetic material functioning as a magnetic switch so that the circuit can mitigate resonances caused by reflected energy without any significant degradation of its switching function as part of an saturable reactor inductor.
Claims
1. A pulse power circuit for supplying pulses to a laser chamber, the pulse power circuit including an inductor having a hybrid saturable magnetic core comprising: a switch magnetic material arranged and selected to function as a magnetic switch; and a damping magnetic material arranged and selected to damp reflections from the laser chamber without interfering with the switch magnetic material functioning as a magnetic switch.
2. A pulse power circuit as claimed in claim 1 wherein when the inductor is biased to a bias point, a magnitude of a hysteresis of the damping magnetic material at the bias point is greater than a magnitude of a hysteresis of the switch magnetic material at the bias point.
3. A pulse power circuit as claimed in claim 1 wherein the switch magnetic material operates as a switch primarily in a switching range of field strengths between H.sub.C and +H.sub.C of the switch magnetic material, wherein the switch magnetic material has a minimum magnetic permeability .sub.SWITCH in the switching range, and wherein the damping magnetic material has a maximum magnetic permeability .sub.DAMPER in the switching range, and wherein .sub.DAMPER is less than .sub.SWITCH.
4. A pulse power circuit as claimed in claim 2 wherein the switch magnetic material operates as a switch primarily in a switching range of field strengths between H.sub.C and +H.sub.C of the switch magnetic material, wherein the switch magnetic material has a minimum magnetic permeability .sub.SWITCH in the switching range, and wherein the damping magnetic material has a maximum magnetic permeability .sub.DAMPER in the switching range, and wherein .sub.DAMPER is less than .sub.SWITCH.
5. A pulse power circuit as claimed in claim 1 wherein the switch magnetic material has a first magnetic squareness ratio and the damping magnetic material has a second magnetic squareness ratio less than the first magnetic squareness ratio.
6. A pulse power circuit as claimed in claim 1 wherein the switch magnetic material has a magnetic squareness ratio greater than 0.80.
7. A pulse power circuit as claimed in claim 6 wherein the damping magnetic material has a magnetic squareness ratio less than 0.80.
8. A pulse power circuit as claimed in claim 1 wherein the damping magnetic material comprises a weight percentage of the saturable magnetic core in the range of 0.50% to 10%.
9. A pulse power circuit as claimed in claim 1 wherein the damping magnetic material comprises a weight percentage of the saturable magnetic core on the order of 1%.
10. An inductor having a hybrid saturable magnetic core comprising: a switch magnetic material arranged and selected to function as a magnetic switch; and a damping magnetic material arranged and selected to damp reflections from the laser chamber without interfering with the first magnetic material functioning as a magnetic switch.
11. An inductor as claimed in claim 10 wherein when the inductor is biased to a bias point, a magnitude of a hysteresis of the damping magnetic material at the bias point is greater than a magnitude of a hysteresis of the switch magnetic material at the bias point.
12. An inductor as claimed in claim 10 wherein the switch magnetic material operates as a switch primarily in a switching range of field strengths between H.sub.C and +H.sub.C of the switch magnetic material, wherein the switch magnetic material has a minimum magnetic permeability .sub.SWITCH in the switching range, and wherein the damping magnetic material has a maximum magnetic permeability .sub.DAMPER in the switching range, and wherein .sub.DAMPER is less than .sub.SWITCH.
13. An inductor as claimed in claim 11 wherein the switch magnetic material operates as a switch primarily in a switching range of field strengths between H.sub.C and +H.sub.C of the switch magnetic material, wherein the switch magnetic material has a minimum magnetic permeability .sub.SWITCH in the switching range, and wherein the damping magnetic material has a maximum magnetic permeability .sub.DAMPER in the switching range, and wherein .sub.DAMPER is less than .sub.SWITCH.
14. An inductor as claimed in claim 10 wherein the switch magnetic material has a first magnetic squareness ratio and the damping magnetic material has a second magnetic squareness ratio less than the first magnetic squareness ratio.
15. An inductor as claimed in claim 10 wherein the switch magnetic material has a magnetic squareness ratio greater than 0.8.
16. An inductor as claimed in claim 10 wherein the damping magnetic material has a magnetic squareness ratio less than 0.8.
17. An inductor as claimed in claim 10 wherein the damping magnetic material comprises a weight percentage of the saturable magnetic core in the range of 0.5% to 10%.
18. An inductor as claimed in claim 10 wherein the damping magnetic material comprises a weight percentage of the saturable magnetic core on the order of 1%.
19. An inductor comprising: a plurality of first toroidal elements arranged in a stack, the first toroidal elements comprising a switch magnetic material arranged and selected to function as a magnetic switch; and at least one second toroidal element arranged in the stack, the second toroidal element comprising a damping magnetic material arranged and selected to damp pulse energy reflections without interfering with the switch magnetic material functioning as a magnetic switch.
20. An inductor comprising: a toroid formed of a tape wound into one or more turns, the tape having a radial cross section when wound comprising at least one first layer made of a switch material selected to function as a magnetic switch and at least one second layer made of a damping material selected to damp pulse energy reflections without interfering with the switch magnetic material functioning as a magnetic switch.
21. A laser system comprising: a laser chamber containing a pair of electrodes; and a pulsed power supply system arranged to supply pulses to the electrodes, the pulsed power system including a hybrid saturable core reactor, the hybrid saturable core reactor comprising a switch magnetic material arranged and selected to function as a magnetic switch and a damping magnetic material arranged and selected to damp reflections from the laser chamber without interfering with the switch magnetic material functioning as a magnetic switch.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate the present invention and, together with the description, further serve to explain the principles of the present invention and to enable a person skilled in the relevant art(s) to make and use the present invention.
[0016]
[0017]
[0018]
[0019]
[0020]
[0021]
[0022]
[0023]
[0024] The features and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, in which like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements.
DETAILED DESCRIPTION
[0025] This specification discloses one or more embodiments that incorporate the features of this invention. The disclosed embodiment(s) merely exemplify the present invention. The scope of the present invention is not limited to the disclosed embodiment(s). The present invention is defined by the claims appended hereto.
[0026] The embodiment(s) described, and references in the specification to one embodiment, an embodiment, an example embodiment, etc., indicate that the embodiment(s) described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is understood that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.
[0027] Turning to
[0028]
[0029] The saturable reactor 55 initially resists the flow of current from capacitor 60. More specifically, normally, before a pulse is fired, the saturable reactor 55 is biased to negative saturation. (The saturable reactor 55 can oppose incoming current even without a bias current but the bias current is used to provide an increased (even to a maximum) and stable flux swing.) When the next pulse energy comes from capacitor 50 to charge capacitor 60, the current induces an opposing electromotive force in the core of the saturable reactor 55 to oppose the incoming current until the core becomes saturated in the forward direction. Upon saturation the opposing electromotive force disappears, and the charge accumulated on capacitor 60 transfers as if a circuit switch has suddenly closed.
[0030] Saturable reactor 55 thus functions as a magnetic switch for the pulsed laser. The saturable magnetic core gives the inductor two states. In one state the inductance of the saturable reactor is high because the magnetic core has a high permeability. In the other state the inductance is low because the magnetic core has been driven into saturation, corresponding to a low permeability.
[0031] The magnetic core of the saturable reactor may be in any one of several forms including powder cores, ferrite cores, and tape-wound cores. An example of a tape-wound core 100 is shown in
[0032] Tape-wound cores are made from thin strips of high permeability nickel-iron alloys including grain-oriented 50% nickel-iron alloys, non-oriented 80% nickel-iron alloy, and grain-oriented 3% silicon-iron alloy. These are some examples of materials. It will be apparent that the list is not exhaustive, and that many other materials may be used.
[0033] The cores for saturable reactors used in such an application have conventionally been required to exhibit a particular hysteresis squareness or B.sub.r/B.sub.sat ratio. This is because for ideal operation as a switch the core material should exhibit an almost square hysteresis curve as described more fully below. One characteristic of a square curve is that the knee in the curve where the magnetization B starts to fall off with decreasing (negative) field strength H is sharp.
[0034] One technical issue in the design of the power supply is the reflection of the pulse by the electrodes in the laser chamber module 36. These reflections can cause ringing that can interfere with the ability of the pulse circuitry to be ready to deliver the next pulse. Various measures have been employed to control this reflected energy. In this regard, see U.S. Pat. No. 5,729,562, titled Pulse Power Generating Circuit with Energy Recovery and issued Mar. 17, 1998, the entire specification of which is incorporated herein by reference.
[0035] According to an aspect of an embodiment, the reflected energy is further controlled by modifying the saturable reactor core to include, in addition to the switch magnetic material that dominates the switching behavior, a damper magnetic material with characteristics that cause the damping magnetic material to dampen out the reflected energy. The damping magnetic material is selected, however, so that it does not interfere with the switching operation of the switch magnetic material during pulse generation. This results in a hybrid core that performs both a switching function in pulse generation and a damping function after pulse generation. Here and elsewhere the term interfere is used to mean that while each of the magnetic materials may have some effect in the other's operational domain (switching v. damping), the out-of-domain effect is small enough that it does not unduly impede the function of the other material in its domain. Thus, the damping magnetic material does not interfere with the switching function of the switch magnetic material during switching, and the switch magnetic material does not interfere with the damping function of the damping magnetic material during reflection damping.
[0036] There are several ways of characterizing and selecting the damping magnetic material to achieve the desired end of reducing reflections without impairing switching.
[0037] According to an aspect of an embodiment, the advantages of using a high squareness material are retained for the switch magnetic material. Oscillations caused by reflected chamber energy are controlled, however, by adding a portion of lower squareness damping magnetic material to the core to create a hybrid core. As used herein, hybrid is intended to connote a combination of materials in which each material is discrete and distinct and retains its individual magnetic properties.
[0038] The broken line in
[0039] According to an aspect of an embodiment the damping magnetic material is selected so that B.sub.r(damper)/B.sub.SAT(damper)=B.sub.r(switch)/B.sub.SAT(switch) where B.sub.r(damper) is the magnetic remanence of the damping magnetic material; B.sub.SAT(damper) is the saturation or maximum magnetic strength of the damping magnetic material; B.sub.r(switch) is the magnetic remanence of the switch magnetic material; and B.sub.sAT(switch) is the saturation or maximum magnetic strength of the switch magnetic material.
[0040] According to one aspect, the damping magnetic material is selected so that H.sub.C(damper)>H.sub.C(switch), where H.sub.C(damper) is the coercivity of the damping magnetic material and H.sub.C(switch) is the coercivity of the damping magnetic material. According to another aspect, even if H.sub.C(damper) is small, the damping material can still damp out energy coming back from chamber if the curve around the knee point is relatively rounded as shown in the broken ellipse in
[0041] As can be seen in
[0042] In other words, according to an aspect of an embodiment, at the bias point the damping magnetic material hysteresis dominates the switch magnetic material hysteresis while in the switch operating range the magnetic permeability of the switch magnetic material dominates the magnetic permeability of the damping magnetic material. Thus, each material is effective in its own operational regime and does not interfere with the effectiveness of the other material in the other material's regime.
[0043] As another example, the broken line in
[0044] The number of materials may be two or more than two. In the example in which two materials make up the hybrid core material, the switch magnetic material can exhibit relatively high squareness while the damping magnetic material may exhibit a relatively low squareness. For some embodiments, the switch magnetic material may have a squareness in the range of 0.8 to 1. Also, for some embodiments, the damping magnetic material may have relatively low squareness may have a squareness less than 0.8.
[0045] According to another aspect of an embodiment, given a permeability ratio .sub.max/.sub.sat for the switching material and a similarly defined permeability ratio for the damping material, respectively, it will be advantageous to have a relatively larger permeability ratio for the switching material and a relatively smaller permeability ratio for the damping material. Here p. is taken to be the slope of BH curve over switching region.
[0046] As regarding the physical structure of the magnetic core, as mentioned above the core can be configured as a cylindrical stack of toroidal elements. An example of this configuration is shown in
[0047] As shown in
[0048]
[0049] The ratio by weight of the amount of damping magnetic material to damping magnetic material may be varied. For example, the amount of damping magnetic material by weight in the hybrid core may comprise 0.5 to 10 percent of the weight of the hybrid core. As another example, the hybrid core may comprise 1% damping magnetic material by weight.
[0050] Hybrid saturable magnetic cores such as those just described can be incorporated into inductors used as saturable core reactors in the pulse power circuitry described above.
[0051] While the foregoing description is primarily in terms of tape-wound cores for the sake of having a concrete example to facilitate a better understanding, it will be apparent to one of ordinary skill in the art that the principles set forth herein can also be applied to other types of cores.
[0052] It is to be appreciated that the Detailed Description section, and not the Summary and Abstract sections, is intended to be used to interpret the claims. The Summary and Abstract sections may set forth one or more but not all exemplary embodiments of the present invention as contemplated by the inventor(s), and thus, are not intended to limit the present invention and the appended claims in any way.
[0053] The present invention has been described above with the aid of functional building blocks illustrating the implementation of specified functions and relationships thereof. The boundaries of these functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternate boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed.
[0054] The foregoing description of the specific embodiments will so fully reveal the general nature of the present invention that others can, by applying knowledge within the skill of the art, readily modify and/or adapt for various applications such specific embodiments, without undue experimentation, without departing from the general concept of the present invention. Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance.
[0055] The embodiments can be further described using the following clauses: [0056] 1. A pulse power circuit for supplying pulses to a laser chamber, the pulse power circuit including an inductor having a hybrid saturable magnetic core comprising: [0057] a switch magnetic material arranged and selected to function as a magnetic switch; and a damping magnetic material arranged and selected to damp reflections from the laser chamber without interfering with the switch magnetic material functioning as a magnetic switch. [0058] 2. A pulse power circuit of clause 1 wherein when the inductor is biased to a bias point, a magnitude of a hysteresis of the damping magnetic material at the bias point is greater than a magnitude of a hysteresis of the switch magnetic material at the bias point. [0059] 3. A pulse power circuit of clause 1 wherein the switch magnetic material operates as a switch primarily in a switching range of field strengths between H.sub.C and +H.sub.C of the switch magnetic material, wherein the switch magnetic material has a minimum magnetic permeability .sub.SWITCH in the switching range, and wherein the damping magnetic material has a maximum magnetic permeability .sub.DAMPER in the switching range, and wherein .sub.DAMPER is less than .sub.SWITCH. [0060] 4. A pulse power circuit of clause 2 wherein the switch magnetic material operates as a switch primarily in a switching range of field strengths between H.sub.C and +H.sub.C of the switch magnetic material, wherein the switch magnetic material has a minimum magnetic permeability .sub.SWITCH in the switching range, and wherein the damping magnetic material has a maximum magnetic permeability .sub.DAMPER in the switching range, and wherein .sub.DAMPER is less than .sub.SWITCH. [0061] 5. A pulse power circuit of clause 1 wherein the switch magnetic material has a first magnetic squareness ratio and the damping magnetic material has a second magnetic squareness ratio less than the first magnetic squareness ratio. [0062] 6. A pulse power circuit of clause 1 wherein the switch magnetic material has a magnetic squareness ratio greater than 0.80. [0063] 7. A pulse power circuit of clause 6 wherein the damping magnetic material has a magnetic squareness ratio less than 0.80. [0064] 8. A pulse power circuit of clause 1 wherein the damping magnetic material comprises a weight percentage of the saturable magnetic core in the range of 0.50% to 10%.9. [0065] 9. A pulse power circuit of clause 1 wherein the damping magnetic material comprises a weight percentage of the saturable magnetic core on the order of 1%. [0066] 10. An inductor having a hybrid saturable magnetic core comprising: [0067] a switch magnetic material arranged and selected to function as a magnetic switch; and [0068] a damping magnetic material arranged and selected to damp reflections from the laser chamber without interfering with the first magnetic material functioning as a magnetic switch. [0069] 11. An inductor of clause 10 wherein when the inductor is biased to a bias point, a magnitude of a hysteresis of the damping magnetic material at the bias point is greater than a magnitude of a hysteresis of the switch magnetic material at the bias point. [0070] 12. An inductor of clause 10 wherein the switch magnetic material operates as a switch primarily in a switching range of field strengths between H.sub.C and +H.sub.C of the switch magnetic material, wherein the switch magnetic material has a minimum magnetic permeability .sub.SWITCH in the switching range, and wherein the damping magnetic material has a maximum magnetic permeability .sub.DAMPER in the switching range, and wherein .sub.DAMPER is less than .sub.SWITCH. [0071] 13. An inductor of clause 11 wherein the switch magnetic material operates as a switch primarily in a switching range of field strengths between H.sub.C and +H.sub.C of the switch magnetic material, wherein the switch magnetic material has a minimum magnetic permeability .sub.SWITCH in the switching range, and wherein the damping magnetic material has a maximum magnetic permeability .sub.DAMPER in the switching range, and wherein .sub.DAMPER is less than .sub.SWITCH. [0072] 14. An inductor of clause 10 wherein the switch magnetic material has a first magnetic squareness ratio and the damping magnetic material has a second magnetic squareness ratio less than the first magnetic squareness ratio. [0073] 15. An inductor of clause 10 wherein the switch magnetic material has a magnetic squareness ratio greater than 0.8. [0074] 16. An inductor of clause 10 wherein the damping magnetic material has a magnetic squareness ratio less than 0.8. [0075] 17. An inductor of clause 10 wherein the damping magnetic material comprises a weight percentage of the saturable magnetic core in the range of 0.5% to 10%. [0076] 18. An inductor of clause 10 wherein the damping magnetic material comprises a weight percentage of the saturable magnetic core on the order of 1%. [0077] 19. An inductor comprising: [0078] a plurality of first toroidal elements arranged in a stack, the first toroidal elements comprising a switch magnetic material arranged and selected to function as a magnetic switch; and [0079] at least one second toroidal element arranged in the stack, the second toroidal element comprising a damping magnetic material arranged and selected to damp pulse energy reflections without interfering with the switch magnetic material functioning as a magnetic switch. [0080] 20. An inductor comprising: [0081] a toroid formed of a tape wound into one or more turns, the tape having a radial cross section when wound comprising at least one first layer made of a switch material selected to function as a magnetic switch and at least one second layer made of a damping material selected to damp pulse energy reflections without interfering with the switch magnetic material functioning as a magnetic switch. [0082] 21. A laser system comprising: [0083] a laser chamber containing a pair of electrodes; and [0084] a pulsed power supply system arranged to supply pulses to the electrodes, the pulsed power system including a hybrid saturable core reactor, the hybrid saturable core reactor comprising a switch magnetic material arranged and selected to function as a magnetic switch and a damping magnetic material arranged and selected to damp reflections from the laser chamber without interfering with the switch magnetic material functioning as a magnetic switch.
[0085] Other embodiments and implementations are found within the scope of the following claims.