JP5216704B2 - Transformer - Google Patents

Description

  The present invention relates to a transformer used in an electron beam tube power supply device, and more particularly to a transformer used in an electron beam tube power supply device for the purpose of generating charged particle accelerators or electromagnetic waves.

  Conventionally, in a transformer, when an electric field is concentrated on a high voltage portion of a winding, insulation breakdown due to invasion of an external surge voltage, deterioration of insulation due to partial discharge, or the like may occur. For this reason, measures have been taken to provide a shielding electrode in the vicinity of the end of the winding (see, for example, Patent Document 1).

There is also a transformer in which an insulating cylinder and a spacing member are arranged between a low voltage winding and a high voltage winding. This transformer was intended to suppress electric field concentration in a specific region between the low voltage winding and the high voltage winding (see, for example, Patent Document 2).
As described above, some conventional transformers have electrodes provided in the vicinity of both ends of the winding, and some have an insulating cylinder disposed between two windings.

JP 58-21308 A JP 2000-91131 A

  By the way, a transformer used in a power source device for an electron beam tube for the purpose of generating a charged particle accelerator or electromagnetic wave outputs a voltage composed of a pulse train. This pulse train is composed of square wave pulses. The pulse is required to have a pulse width of a few microseconds to several milliseconds and a pulse peak value of 100 kilovolts or more. Hereinafter, this pulse is referred to as a high voltage pulse.

However, in the conventional transformer, since a stray capacitance is formed between the high voltage winding and the ground potential, resonance occurs due to the stray capacitance and the inductance of the high voltage winding.
For this reason, the oscillation voltage due to resonance is superimposed on the high voltage pulse to be transmitted by the transformer, and the waveform of the high voltage pulse is distorted. Could not be done (see FIG. 5). This will be described in more detail below. In addition, the same code | symbol was attached | subjected about the same thing as FIG. 6 mentioned later among the members and parts shown in FIG.

As shown in FIG. 5A, the stray capacitance described above mainly includes an interwinding capacitance 182, a high voltage winding internal capacitance 184, and a ground capacitance 186. Compared to the high-voltage winding internal capacitance 184, the inter-winding capacitance 182 and the ground-to-ground capacitance 186 are larger. When these interwinding capacitance 182 and ground capacitance 186 are large, the potential along the axial direction of the high voltage winding 120 immediately after the rising of the high voltage pulse is as shown in FIG. As shown by the solid line in the graph, the distance greatly changes as the second end 124 is approached. For this reason, immediately after the rising of the high voltage pulse, in order to charge the inter-winding capacitance 182 and the ground-to-ground capacitance 186, the inter-winding capacitance 182, The charge moves to the capacitance 186 between the ground. Thereafter, as shown by the broken line in the graph of FIG. 5B, the change in potential due to the induced electromotive force of the conventional transformer becomes linear along the axial direction of the high voltage winding 120.
A magnetic field is generated by the movement of the electric charge, and a resonance phenomenon appears between the inductance due to the generated magnetic field and the inter-winding capacitance 182 and the ground-to-ground capacitance 186, and an oscillating voltage having a period in the microsecond range is generated. Since this oscillating voltage changes the pulse peak value with time after the rising of the high voltage pulse, the waveform of the high voltage pulse is distorted from the square wave, and the high voltage of the square wave is applied to the accelerator or electron tube that is the load. The pulse could not be supplied.

  In an electron beam tube power supply for the purpose of a charged particle accelerator or electromagnetic wave generation, it is necessary to keep the energy applied to the charged particles and the intensity of the electromagnetic wave constant. For this reason, there is a demand to keep the fluctuation of the pulse peak value of the high voltage pulse supplied to these devices within several percent, but the conventional transformer cannot always satisfy this demand due to the above-mentioned vibration voltage.

  The present invention has been made in view of the above points, and the object of the present invention is to reduce the influence of stray capacitance generated around the windings constituting the transformer, and after the rising of the high voltage pulse. An object of the present invention is to provide a transformer capable of suppressing the temporal change of the pulse peak value of a high voltage pulse.

The transformer according to the present invention is
A transformer having a primary winding having a cylindrical shape, the secondary winding and having the primary winding and concentrically disposed a cylindrical shape on the outside of the primary winding ,
Having a counter electrode arranged around the secondary winding on the outside of the secondary winding ;
The counter electrode is arranged at the center part in the axial direction of the secondary winding, or opposed to the ground potential side from the center part,
The secondary winding and the counter electrode are electrically connected.

With this configuration, the amount of charge that is moved by the stray capacitance generated around the secondary winding is reduced, and the oscillation voltage due to resonance caused by the inductance and stray capacitance due to the movement of the charge is suppressed, thereby suppressing the secondary winding. The distortion of the waveform of the voltage output from can be reduced.
In addition, by correcting the deviation of the potential distribution along the axial direction of the secondary winding and bringing the potential distribution closer to a straight line, the amount of charge movement can be further reduced, and the vibration voltage can be suppressed. The distortion of the waveform of the voltage output from the secondary winding can be reduced.

The secondary winding has a first end and a second end that has a higher potential than the first end,
The potential of the secondary winding at the portion facing the counter electrode is an intermediate potential between the potential of the first end and the potential of the second end,
The counter electrode is preferably one that is electrically connected to a portion of the secondary winding that has a higher potential than the intermediate potential.

  With this configuration, stray capacitance is easily formed between the counter electrode and the intermediate potential, and is equivalent to the stray capacitance (ground-to-ground capacitance) formed between the intermediate potential and the ground potential. Since the voltage is divided by electrostatic capacitance immediately after the high voltage pulse is applied, a voltage of about 1/2 is applied to the intermediate potential, reducing the amount of charge that moves, and by the inductance and stray capacitance due to the movement of charge. The vibration voltage due to the generated resonance can be suppressed, and the distortion of the waveform of the voltage output from the secondary winding can be reduced.

  Furthermore, it is preferable that the distance between the counter electrode and the secondary winding is smaller than the distance between the primary winding and the secondary winding.

  With this configuration, the stray capacitance formed between the secondary winding and the counter electrode is made substantially equal to the stray capacitance formed between the primary winding and the secondary winding. By approximating the distribution of the potential along the axial direction of the secondary winding to a straight line, the amount of charge movement is reduced, and the oscillation voltage is suppressed to reduce the distortion of the voltage waveform output from the secondary winding. Can be small.

  The counter electrode preferably has a cross-sectional shape of a circle, an oval shape or an oval shape.

  Thus, since the outer shape of the electrode is configured by a curved surface, the electric field concentration can be relaxed and partial discharge and dielectric breakdown can be prevented.

  The waveform of the voltage output from the secondary winding is reduced by reducing the amount of charge moving due to the stray capacitance generated around the secondary winding and suppressing the oscillation voltage caused by the resonance caused by the inductance and stray capacitance due to the movement of the charge. Can reduce distortion.

It is a front view which shows the transformer 100 which concerns on 1st embodiment of this invention. It is a top view which shows the transformer 100 which concerns on 1st embodiment of this invention. It is sectional drawing of the transformer 100 along the II-II line | wire of FIG. It is sectional drawing of the transformer 100 along the II line | wire of FIG. It is the reference figure (a) which shows the equivalent circuit of the conventional transformer, and the graph (b) which shows the change of the electric potential in the high voltage winding 120 of the conventional transformer. The figure (a) which shows the equivalent circuit schematic of the transformer 100 which concerns on 1st embodiment of this invention, and the graph which shows the change of the electric potential in the high voltage winding 120 of the transformer 100 which concerns on 1st embodiment of this invention ( b). It is a front view which shows the transformer 200 which concerns on 2nd embodiment of this invention. It is a top view which shows the transformer 200 which concerns on 2nd embodiment of this invention. FIG. 5A is a plan view showing a transformer 300 according to a third embodiment of the present invention, and FIG. 5B is a cross-sectional view of a potential distribution equalization shielding electrode 330 used in the transformer 300.

  Embodiments of the present invention will be described below with reference to the drawings.

[First embodiment]
FIG. 1 is a front view showing a transformer 100 according to the first embodiment of the present invention. 2 is a plan view thereof, and FIG. 3 is a cross-sectional view taken along line II-II in FIG. FIG. 4 is a cross-sectional view taken along the line II of FIG.

  The transformer 100 according to the first embodiment includes a low voltage winding 110, a high voltage winding 120, a potential distribution equalization shielding electrode 130, a support bar 140, and an iron core 150.

<Low voltage winding 110, high voltage winding 120, iron core 150>
The iron core 150 is formed in an annular shape and constitutes a magnetic circuit. The iron core 150 has an iron core leg 152 formed in a substantially quadrangular prism shape. As shown in FIG. 4, the low voltage winding 110 and the high voltage winding 120 are wound around the core leg 152 in a concentric manner with the core leg 152 as an axis. The low voltage winding 110 corresponds to a “primary winding”, and the high voltage winding 120 corresponds to a “secondary winding”.

  As shown in FIGS. 3 and 4, the low voltage winding 110 is wound around the iron core leg 152 via the insulator 160 and has a cylindrical shape. The high voltage winding 120 is wound around the outer periphery of the low voltage winding 110 via an insulator 162 and has a cylindrical shape. These insulators 160 and 162 can use insulating oil, air, or the like.

  In the first embodiment, as shown in FIG. 3, the axial center O1 of the low voltage winding 110 and the axial center O2 of the high voltage winding 120 are substantially the same position in the axial direction. It is arranged to be. Each of the low voltage winding 110 and the high voltage winding 120 has a predetermined number of turns. In the transformer 100, voltage and current are converted according to the turn ratio between the low voltage winding 110 and the high voltage winding 120.

  The low voltage winding 110 has a first end 112 and a second end 114 (see FIG. 6A). In FIG. 1 or FIG. 3, the first end portion 112 is located on the lower side, and the second end portion 114 is located on the upper side. A power source (not shown) is connected to the first end portion 112 and the second end portion 114, and a power source voltage is applied to the low voltage winding 110. The supply voltage applied to the low voltage winding 110 is boosted according to the turn ratio between the low voltage winding 110 and the high voltage winding 120, and a voltage boosted from the high voltage winding 120 (boosted voltage) is output. Is done.

On the other hand, the high voltage winding 120 has a first end 122 and a second end 124 (see FIG. 6A). In FIG. 1 or FIG. 3, the first end 122 is located on the lower side, and the second end 124 is located on the upper side. The first end 122 is grounded and has a ground potential. On the other hand, when the high voltage pulse is output from the transformer 100, the second end portion 124 has a potential (high potential) corresponding to the above-described boosted voltage. A load (not shown) is connected to the first end 122 and the second end 124, the boosted voltage output from the high voltage winding 120 is applied to the load, and the high voltage pulse is applied to the load. To be supplied.
Examples of the load include a charged particle accelerator and an electron beam tube power supply for the purpose of generating electromagnetic waves. Hereinafter, not only the second end portion 124 but also a portion that is electrically connected to the second end portion 124 and has the same potential as the second end portion 124, that is, a portion that can have a potential corresponding to the boosted voltage. It is called a high potential site.

<High voltage side shielding electrode 170>
As shown in FIGS. 1 and 2, a high voltage side shield electrode 170 is provided at the upper end of the high voltage winding 120. The high-voltage side shield electrode 170 has an annular shape with a substantially circular cross section, and a gap 172 is formed in a part of the circumferential direction. Occurrence of eddy current flowing in the circumferential direction of the high-voltage side shield electrode 170 can be prevented by the gap 172. The high-voltage side shielding electrode 170 is electrically connected to the second end portion 124, and the high-voltage side shielding electrode 170 is also a high potential portion.

  The high-voltage side shield electrode 170 is a member for the purpose of relaxing the electric field. That is, the electric field tends to concentrate on the upper end portion of the high voltage winding 120, and the high voltage side shielding electrode 170 having an annular shape having a substantially circular cross section is provided on the upper end portion of the high voltage winding 120. Partial discharge and dielectric breakdown caused by concentration can be prevented.

<Electric potential distribution equalization shielding electrode (counter electrode) 130>
As shown in FIG. 2, four support rods 140 are electrically connected to the upper end portion of the high voltage winding 120 or the high voltage side shielding electrode 170. These four support rods 140 are arranged at an interval of approximately 90 degrees in the circumferential direction of the upper end portion of the high voltage winding 120 or the high voltage side shield electrode 170. As described above, since the potential of the high-voltage side shield electrode 170 is high, the potentials of the four support bars 140 are also high.
This potential distribution equalization shielding electrode 130 corresponds to a “counter electrode”. The support rod 140 and the high voltage side shield electrode 170 function as a connection body that connects the high voltage winding 120 and the voltage distribution equalization shield electrode 130. The four support rods 140 are not limited to being connected to the high-voltage side shield electrode 170 but may be electrically connected to either the upper end of the high-voltage winding 120 or the high-voltage side shield electrode 170. That's fine.

  The support bar 140 is made of a conductor having a long shape with a substantially circular cross section. The support bar 140 has two end portions, and one end portion is connected to the upper end portion of the high voltage winding 120 or the high voltage side shielding electrode 170 as described above. As shown in FIG. 1 or FIG. 3, each of the four support rods 140 is separated from the outer peripheral surface 126 of the high voltage winding 120 as it goes downward along the axial direction of the high voltage winding 120. Has been placed. Since the curved surface is formed by making the cross-sectional shape of the support rod 140 substantially circular, partial discharge can be prevented. Further, the cross-sectional shape of the support bar 140 may be an oval shape. Also in this case, since the curved surface is formed, partial discharge can be prevented.

As shown in FIGS. 1 and 2, the other end of each of the four support rods 140 is arranged on the potential distribution equalization shielding electrode 130 at intervals of about 90 degrees in the circumferential direction of the potential distribution equalization shielding electrode 130. It is connected. The potential distribution equalization shielding electrode 130 is supported by the four support rods 140, thereby being positioned at the axial center O <b> 1 of the low voltage winding 110 and the axial center O <b> 2 of the high voltage winding 120. To be arranged. The potential distribution equalization shielding electrode 130 has a substantially circular cross section and a substantially annular shape.
As shown in FIG. 3, the inner peripheral curved surface (a semicircular portion facing the inside, the electrode surface) 134 of the cross-sectional shape of the potential distribution equalizing shield electrode 130 is the central portion O2 in the axial direction of the high voltage winding 120. Thus, it faces the outer peripheral surface 126 of the high voltage winding 120.

  Further, as shown in FIG. 4, the potential distribution equalization shielding electrode 130 is formed with a gap 132 in a part in the circumferential direction. Occurrence of eddy current flowing in the circumferential direction of the potential distribution equalizing shield electrode 130 can be prevented by the gap 132. The potential distribution equalization shielding electrode 130 circulates around the high voltage winding 120 and is disposed so as to have a gap (see FIG. 3) having a distance L1 with respect to the high voltage winding 120.

  As described above, the support bar 140 is made of a conductor, and the potential distribution equalization shielding electrode 130 is connected to the second end of the high-voltage winding 120 via the support bar 140 and the high-voltage side shielding electrode 170. The part 124 is electrically connected. Therefore, the potential distribution equalization shielding electrode 130 can be set to the same potential as the second end portion 124. That is, the potential of the potential distribution equalization shielding electrode 130 becomes a high potential.

On the other hand, when a high voltage pulse is output from the transformer 100, the potential at the central portion O2 in the axial direction of the high voltage winding 120 facing the potential distribution equalization shielding electrode 130 is the potential at the first end 122. It becomes an intermediate potential (hereinafter referred to as an intermediate potential) that is higher than the ground potential and lower than the high potential that is the potential of the second end portion 124.
Therefore, when a high voltage pulse is output from the transformer 100, a potential difference is generated between the curved surface 134 of the potential distribution equalization shielding electrode 130 and the outer peripheral surface 126 of the high voltage winding 120, and the potential distribution equalization shielding is performed. An electric field can be generated between the electrode 130 and the high voltage winding 120. When such an electric field is generated, a stray capacitance 180 (see FIG. 6A) is formed between the potential distribution equalization shielding electrode 130 and the high voltage winding 120.
As described above, the stray capacitance 180 is a stray capacitance formed between the intermediate potential and the high potential. The size of the stray capacitance 180 depends on the diameter of the potential distribution equalization shielding electrode 130 and the distance L1 of the gap between the curved surface 134 of the potential distribution equalization shielding electrode 130 and the outer peripheral surface 126 of the high voltage winding 120. You can change it to what you want.

FIG. 6A is a diagram showing an equivalent circuit diagram including stray capacitance generated around the low voltage winding 110 and the high voltage winding 120 of the transformer 100 according to the first embodiment of the present invention.
A stray capacitance 182 is formed between the low voltage winding 110 and the high voltage winding 120. In addition, a stray capacitance 184 generated inside the high voltage winding 120 and a stray capacitance 186 between the ground are formed. Furthermore, as described above, by providing the potential distribution equalization shielding electrode 130, the stray capacitance 180 is formed between the potential distribution equalization shielding electrode 130 and the high voltage winding 120.

  FIG.6 (b) is a graph which shows the change of the electric potential in the high voltage winding 120 of the transformer 100 which concerns on 1st embodiment of this invention. The horizontal axis of the graph shown in FIG. 6B indicates the position along the axial direction of the high voltage winding 120. Specifically, the position from the first end 122 to the second end 124 is shown with the first end 122 as the origin. Further, the vertical axis of the graph shown in FIG. 6B indicates the potential of the high voltage winding 120 corresponding to the position from the first end 122 to the second end 124.

As shown in FIG. 6B, the potential of the high voltage winding 120 gradually increases from the first end portion 122 toward the second end portion 124 in a form close to a straight line. Further, the potential changes in a substantially symmetrical manner with the central portion O2 in the axial direction of the high voltage winding 120 as the center. In this way, by forming the stray capacitance 180 formed between the intermediate potential and the high potential by the potential distribution equalization shielding electrode 130, the potential distribution along the axial direction of the high voltage winding 120 is substantially reduced. It can be close to a straight line.
As a result, the amount of charge transferred to the stray capacitance 182 between the low voltage winding 110 and the high voltage winding 120 and the stray capacitance 186 between the ground is reduced immediately after the rising of the high voltage pulse. it can. For this reason, it is possible to suppress the inductance due to the magnetic field generated by the movement of electric charges and the oscillating voltage due to the resonance phenomenon between the stray capacitance 182 and the stray capacitance 186, and the distortion of the waveform of the high voltage pulse output from the transformer 100 can be reduced. Can be small.

Further, a distance L1 between the curved surface 134 of the potential distribution equalization shielding electrode 130 and the outer peripheral surface 126 of the high voltage winding 120 is set as a distance L2 between the low voltage winding 110 and the high voltage winding 120 (FIG. 3). The size of the stray capacitance 180 formed between the central portion O2 of the high voltage winding 120 and the potential distribution equalization shielding electrode 130 is reduced to be smaller than the reference portion). And the size of the stray capacitance 182 formed between the low voltage winding 110 and the low voltage winding 110.
By doing so, the potential distribution along the axial direction of the high-voltage winding 120 can be made substantially linear. Therefore, the amount of movement of charge charged in the stray capacitance 182 and the stray capacitance 186 between the ground and the ground. And the distortion of the waveform of the high voltage pulse can be reduced.

  Further, as described above, the shape of the cross section of the potential distribution equalization shielding electrode 130 is substantially circular, and the surface facing the outer peripheral surface 126 of the high voltage winding 120 is the curved surface 134 having a circular arc cross section. Thus, the surface facing the outer peripheral surface 126 of the high voltage winding 120 is the curved surface 134, so that the electric field generated between the potential distribution equalization shielding electrode 130 and the high voltage winding 120 can be prevented from being concentrated. , The electric field can be relaxed. Even with the configuration in which the potential distribution equalizing shield electrode 130 is provided, it is possible to prevent dielectric breakdown and insulation deterioration.

[Second Embodiment]
FIG. 7 is a front view showing a transformer 200 according to the second embodiment of the present invention. FIG. 8 is a plan view thereof. The transformer 200 according to the second embodiment has a configuration in which two substantially the same ones as the transformer 100 according to the first embodiment are provided. That is, as shown in FIGS. 7 and 8, the transformer 200 includes a first transformer leg 101a and a second transformer leg 101b.
As will be described later, the first transformer leg 101a and the second transformer leg 101b are different from the transformer 100 according to the first embodiment in that the potential distribution equalizing shield electrodes 130a and 130b are different. Shape.

  The transformer 200 according to the second embodiment has an iron core 250. The iron core 250 is formed in an annular shape and constitutes a magnetic circuit. The iron core 250 has iron core legs 252a and 252b formed in a substantially quadrangular prism shape.

  The first transformer leg 101a includes a low voltage winding 110a, a high voltage winding 120a, a potential distribution equalization shielding electrode 130a, and a support bar 140a. The low voltage winding 110a and the high voltage winding 120a are wound around the iron core leg 252a concentrically with the iron core leg 252a described above as an axis.

  The low voltage winding 110a corresponds to the low voltage winding 110 of the transformer 100 according to the first embodiment, and the high voltage winding 120a corresponds to the high voltage winding 120 of the transformer 100 according to the first embodiment. The potential distribution equalization shielding electrode 130a corresponds to the potential distribution equalization shielding electrode 130 of the transformer 100 according to the first embodiment, and the support bar 140a is the support bar 140 of the transformer 100 according to the first embodiment. The core leg 252a corresponds to the core leg 152 of the transformer 100 according to the first embodiment, and these have the same structure as the transformer 100 according to the first embodiment and function similarly. .

  Further, an insulator 160a (not shown) that insulates the iron core leg 252a and the low voltage winding 110a, and an insulator 162a (not shown) that insulates the low voltage winding 110a and the high voltage winding 120a from each other. 2) has the same configuration as the first embodiment and functions in the same manner.

  The second transformer leg 101b includes a low voltage winding 110b, a high voltage winding 120b, a potential distribution equalization shielding electrode 130b, and a support bar 140b. Further, the low voltage winding 110b and the high voltage winding 120b are wound around the iron core leg 252b concentrically with the iron core leg 252b described above as an axis.

  The low voltage winding 110b corresponds to the low voltage winding 110 of the transformer 100 according to the first embodiment, and the high voltage winding 120b corresponds to the high voltage winding 120 of the transformer 100 according to the first embodiment. The potential distribution equalization shielding electrode 130b corresponds to the potential distribution equalization shielding electrode 130 of the transformer 100 according to the first embodiment, and the support bar 140b is the support bar 140 of the transformer 100 according to the first embodiment. The core leg 252b corresponds to the core leg 152 of the transformer 100 according to the first embodiment, and these have the same structure as the transformer 100 according to the first embodiment and function similarly. .

  Further, an insulator 160b (not shown) that insulates the iron core leg 252b and the low voltage winding 110b, and an insulator 162b (not shown) that insulates the low voltage winding 110b and the high voltage winding 120b. 2) has the same configuration as the first embodiment and functions in the same manner.

  As described above, the difference from the transformer 100 of the first embodiment is the potential distribution equalization shielding electrodes 130a and 130b. As shown in FIG. 8, the potential distribution equalization shielding electrode 130a includes two legs 136a and 138a, and has a substantially U shape. The potential distribution equalization shielding electrode 130b includes two legs 136b and 138b, and has a substantially U-shape.

  Potential distribution equalization shielding electrode 130a leg portion 136a and potential distribution equalization shielding electrode 130b leg portion 136b face each other, potential distribution equalization shielding electrode 130a leg portion 138a and potential distribution equalization The leg portions 138b of the shielding electrode 130b are arranged so as to face each other. A gap 132A is formed between the leg portions 136a and 136b facing each other, and a gap 132B is formed between the leg portions 138a and 138b facing each other. By forming the gap 132A and the gap 132B in this way, the high voltage windings 120a and 120b of the two legs can be used at different voltages. For example, the heater voltage of the vacuum tube connected as a load can be reduced. It becomes possible to supply.

In the first transformer leg 101a, the potential distribution equalization shielding electrode 130a is disposed so as to face the high voltage winding 120a, and a stray capacitance is formed therebetween. Due to the stray capacitance, the potential distribution of the high voltage winding 120a changes in a form close to a straight line with respect to the position along the axial direction of the high voltage winding 120a. As a result, the amount of charge transferred to the stray capacitance between the low voltage winding 110a and the high voltage winding 120a and the stray capacitance between the ground can be reduced immediately after the rising of the high voltage pulse. For this reason, it is possible to suppress an oscillating voltage due to a resonance phenomenon between the inductance and stray capacitance due to the magnetic field generated by the movement of electric charges.

Also in the second transformer leg 101b, the potential distribution equalization shielding electrode 130b is disposed so as to face the high voltage winding 120b, and a stray capacitance is formed therebetween. Due to this stray capacitance, the potential distribution of the high voltage winding 120a changes in a form close to a straight line with respect to the position along the axial direction of the high voltage winding 120a. The amount of movement of the charge charged in the stray capacitance between the high voltage winding 120a and the stray capacitance between the ground can be reduced immediately after the rising of the high voltage pulse, and the inductance and stray capacitance due to the magnetic field generated by the charge transfer The oscillation voltage due to the resonance phenomenon during the period can be suppressed.

  Thus, by providing a plurality of transformer legs, it can be used as an “inner iron type” transformer in which the winding is divided.

  In the second embodiment described above, the low-voltage windings 110a and 110b correspond to “primary windings”, and the high-voltage windings 120a and 120b correspond to “secondary windings” and have the same potential distribution. The shield electrodes 130a and 130b correspond to “counter electrodes”.

[Third embodiment]
FIG. 9A is a front view showing a transformer 300 according to the third embodiment of the present invention, and FIG. 9B is a cross-sectional view of a potential distribution equalization shielding electrode 330 used in the transformer 300. In addition, in the transformer 300 of this third embodiment, the same code | symbol was attached | subjected about the structure similar to the transformer 100 of 1st embodiment.

  The transformer 300 of the third embodiment includes a low voltage winding 110, a high voltage winding 120, a potential distribution equalization shielding electrode 330, a support bar 140, and an iron core 150. The low voltage winding 110, the high voltage winding 120, the support rod 140, and the iron core 150 have the same structure as the transformer 100 of the first embodiment and function in the same manner. Further, an insulator 160 (not shown) that insulates the iron core 150 and the low voltage winding 110, and an insulator 162 (not shown) that insulates the low voltage winding 110 and the high voltage winding 120 from each other. ) Has the same configuration as that of the first embodiment and functions in the same manner.

<Electric potential distribution equalization shielding electrode (counter electrode) 330>
As shown in FIG. 9 (b), the potential distribution equalizing shield electrode 330 has an oval cross-section (race-track shaped cross-section), or an oval shape and a substantially annular shape. And a gap (not shown) is formed in a part of the circumferential direction. Occurrence of eddy current flowing in the circumferential direction of the potential distribution equalizing shield electrode 130 can be prevented by the gap (not shown). Like the potential distribution equalization shielding electrode 130, the potential distribution equalization shielding electrode 330 circulates around the high voltage winding 120 and is disposed so as to have a predetermined gap with respect to the high voltage winding 120.

  Similarly to the potential distribution equalization shield electrode 130, the potential distribution equalization shield electrode 330 is electrically connected to and supported by the four support bars 140 made of a conductor. Yes. Therefore, the potential of the potential distribution equalization shielding electrode 330 is also the same as that of the second end 124, that is, a high potential when a high voltage pulse is output from the transformer 100.

  As shown in FIG. 9B, the cross-sectional shape of the potential distribution equalization shielding electrode 330 is oval or oval. That is, the cross section of the potential distribution equalization shielding electrode 330 has a shape in which each of the upper end portion and the lower end portion is substantially semicircular, and a substantially square is disposed between the upper end portion and the lower end portion. By making the surface 334 constituted by the rectangular straight portion face the high voltage winding 120, the area of the surface facing the high voltage winding 120 can be increased.

As described above, by using the potential distribution equalization shielding electrode 330 having an oval or oval cross section, the surface 334 can increase the area of the surface facing the high voltage winding 120.
As a result, the distance between the potential distribution equalizing shield electrode 330 and the high voltage winding 120 is set to be approximately the same as the distance between the low voltage winding 110 and the high voltage winding 120, and the high voltage winding 120. And the stray capacitance formed between the low voltage winding 110 and the high voltage winding 120 can be made substantially equal to each other.
For this reason, it is possible to easily balance the size of the stray capacitance, and the potential distribution of the high voltage winding 120 is changed in a form close to a straight line with respect to the position along the axial direction of the high voltage winding 120. be able to.

  Further, as shown in FIG. 9, the position of the potential distribution equalization shielding electrode 330 is closer to the first end 122 side, that is, the ground side than the central portion of the high voltage winding 120 in the axial direction. In position. Thus, by setting the position close to the ground side, a stray capacitance is formed between the portion near the ground side of the high voltage winding 120 and the potential distribution equalization shielding electrode 330, and the high voltage winding 120 It is possible to prevent the potential distribution along the axial direction from being biased toward the ground side.

  Further, as described above, the cross-sectional shape of the potential distribution equalization shielding electrode 330 is an oval shape or an oval shape. As described above, each of the upper end portion and the lower end portion is formed in a substantially semicircular shape, so that the electric field can be prevented from being concentrated and the electric field can be relaxed.

[Other embodiments]
As described above with reference to FIG. 3, a gap of a distance L <b> 1 is formed between the curved surface 134 of the potential distribution equalization shielding electrode 130 and the outer peripheral surface 126 of the high voltage winding 120. An insulator having a size and shape suitable for the gap may be provided in the gap.
The dielectric constant of the insulator makes it possible to achieve a desired floating capacitance between the potential distribution equalizing shield electrode 130 and the high voltage winding 120.
Further, since the potential distribution equalization shielding electrode 130 can be supported by the insulator, the potential distribution equalization shielding electrode 130 can be stably disposed outside the high voltage winding 120.

  In the first to third embodiments described above, the configuration in which only one potential distribution equalizing shield electrode 130 or the like is provided along the axial direction of the high voltage winding 120 is shown. A plurality of potential distribution equalization shielding electrodes 130 and the like may be provided along the 120 axial direction.

  By providing a plurality of potential distribution equalization shielding electrodes 130 and the like, the size of the stray capacitance 180 can be easily changed, and the distribution of potentials along the axial direction of the high voltage winding 120 can be made closer to a straight line. Further, by providing a plurality of potential distribution equalization shielding electrodes 130, the weight can be reduced.

  In the first to third embodiments described above, the support rod 140 and the high voltage side shielding electrode 170 electrically connect the high voltage winding (secondary winding) and the potential distribution equalizing shielding electrode (counter electrode). Although connected, it is not limited to this, It can apply also to the transformer which does not have a high voltage | pressure side shielding electrode. In this case, the potential distribution equalization shielding electrode (counter electrode) and one end of the support rod are connected, while the other end of the support rod is connected to the upper end portion (high potential side) of the high voltage winding.

100, 200, 300 Transformer 101a, 101b Transformer leg 110, 110a, 110b Low voltage winding (primary winding)
120, 120a, 120b High voltage winding (secondary winding)
122 1st edge part 124 2nd edge part 130, 130a, 130b, 330 Potential distribution equalization shielding electrode (counter electrode)
134 Curved surface (electrode surface)
334 surface (electrode surface)
140, 140a, 140b Support rod 150, 250 Iron core 170, 170a, 170b High voltage side shielding electrode

Claims (4)

A transformer having a primary winding having a cylindrical shape, the secondary winding and having the primary winding and concentrically disposed a cylindrical shape on the outside of the primary winding ,
Having a counter electrode arranged around the secondary winding on the outside of the secondary winding ;
The counter electrode is arranged at the center part in the axial direction of the secondary winding, or opposed to the ground potential side from the center part,
A transformer formed by electrically connecting the secondary winding and the counter electrode. The secondary winding has a first end and a second end having a higher potential than the first end,
The potential of the secondary winding at the portion facing the counter electrode is an intermediate potential between the potential of the first end and the potential of the second end,
The transformer according to claim 1, wherein the counter electrode is electrically connected to a portion of the secondary winding that has a higher potential than the intermediate potential.   The transformer according to claim 1 or 2, wherein a distance between the counter electrode and the secondary winding is smaller than a distance between the primary winding and the secondary winding. The transformer according to any one of claims 1 to 3 , wherein the counter electrode has a cross-sectional shape of a circle, an oval shape, or an ellipse.

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