JP2022054076A - High-voltage transformer - Google Patents

Abstract

To provide a compact and highly reliable high-voltage transformer with improved insulation in a split winding on a secondary side.SOLUTION: A high-voltage transformer has a cylindrical coil bobbin (100) with a rod-shaped soft magnetic core (203) penetrating therethrough. The outer circumference of a cylinder (101) of the coil bobbin is divided into a primary winding area (103) and a secondary winding area (104) in the longitudinal direction by a plurality of partition plates (D0 to Dn+1). The secondary winding area (104) is further divided into a plurality of split windings (S1 to Sn). Each split winding Si is wound through the insulating paint layers (V1, V2) for a predetermined number of turns. A secondary winding is composed of the plurality of split windings.SELECTED DRAWING: Figure 3

Description

The present invention relates to a high voltage transformer that inputs a relatively low voltage to the primary winding and outputs a high voltage to the secondary winding.

A high voltage transformer that boosts a low voltage of about several tens of volts to a high voltage of about several kV is used in various electric / electronic devices that require a high voltage. For example, a high-pressure transformer is required for a lighting device for a backlight of a liquid crystal monitor, a headlamp of an automobile, and a discharge lamp used as a light source of a copier. However, in recent years, with the miniaturization of electronic devices, there is also a demand for miniaturization of the high voltage transformer itself. Especially for a high-voltage transformer that outputs a high voltage of several kV, it is difficult to achieve both miniaturization and ensuring insulation, and many solutions have been proposed so far.

For example, in the high-voltage transformer disclosed in Patent Document 1, the secondary winding on the high-voltage side is composed of a plurality of divided winding portions, and the arrangement of the divided winding portions is further devised to ensure miniaturization and insulation. We are trying to achieve both.

Further, in the bobbin of the high voltage transformer disclosed in Patent Document 2, the winding portion of the primary winding and the secondary winding is divided into two regions in the longitudinal direction, and the secondary winding is divided into a plurality of windings by a plurality of partition collars. It is divided into winding regions, and the potential difference in each winding region is set within 300V. By dividing the secondary winding with a partition collar, the insulation between the secondary windings is improved, and by applying an insulating coating treatment to the outer peripheral surface of the core, the bobbin is not thickened and the winding is on the high voltage side. It prevents a short circuit with the core.

Further, in Patent Document 3, an insulating film such as kraft paper is wound around the primary winding, and a high-voltage side secondary winding is wound around the insulating film to form a secondary side first layer. Similarly, by sequentially forming the secondary side second layer, the third layer, and the like composed of the insulating film and the secondary winding, the occurrence of creeping discharge is prevented, that is, the insulating property is improved.

Japanese Unexamined Patent Publication No. 10-12453 Japanese Unexamined Patent Publication No. 2009-290163 Jitsukaihei No. 5-73921

According to Patent Documents 1 and 2 described above, a configuration is disclosed in which a coil is wound around a rod-shaped core separately in a primary winding region and a secondary winding region, and the secondary side is divided by a plurality of partition collars. However, interwinding insulation within the divided secondary winding region is not considered.

Further, according to Patent Document 3, a high-voltage transformer in which a primary winding is wound around a core and the secondary winding is wound in a layer while sandwiching an insulating film on the primary winding is disclosed. It is a device for eliminating the drawbacks of the structure in which the winding is divided and wound at the flange, that is, the increase in size and the complexity of the work, and the divided winding is not premised in the first place.

Therefore, an object of the present invention is to improve the insulation property of the split winding on the secondary side and to provide a compact and highly reliable high voltage transformer.

In order to achieve the above object, in the high voltage transformer according to the present invention, the outer circumference of the tubular coil bobbin is divided into a primary winding region and a secondary winding region in the longitudinal direction by a plurality of partition plates, and a secondary winding region is further formed. Each of the divided windings, which is divided into a plurality of divided windings and wound in a region sandwiched between adjacent partition plates, is wound via an insulating coating layer every predetermined number of turns.
According to one aspect of the present invention, in a high-voltage transformer having a tubular coil bobbin through which a rod-shaped soft magnetic core penetrates, the outer periphery of the cylindrical portion of the coil bobbin has a primary winding region in the longitudinal direction due to a plurality of partition plates. It is divided into a secondary winding region, and the secondary winding region is further divided into a plurality of divided winding regions, and each of the plurality of divided windings is coated with an insulating paint for each predetermined number of turns. It is characterized in that it is wound through a layer and a secondary winding is formed by the plurality of divided windings. As a result, dielectric breakdown can be prevented even with a high voltage output, and a compact and highly reliable high-voltage transformer can be realized.
The cylinder portion of the coil bobbin and the plurality of partition plates may be formed of an insulating resin having a certain thickness. This enables insulation and simplification of the manufacturing process.
The coating layer can be formed by coating a high-frequency varnish on the windings each time the windings are wound a predetermined number of times. Since it is formed by applying varnish, it is easier to manufacture than using insulating paper, and further miniaturization can be promoted.
The primary winding is wound in the primary winding region for 24 to 48 turns, and each split winding is wound in the secondary winding region for 350 to 500 turns in total for 5000 to 10000 turns, and every 100 turns in each split winding. The coating layer can be formed. Further, by inputting a pulse voltage of 24 to 48V to both ends of the primary winding, 4000 to 5000V can be output to both ends of the secondary winding. By opening the split winding in this way, it is possible to realize a high voltage output of 4000 to 5000 V without dielectric breakdown.

According to the present invention, it is possible to improve the insulation property of the split winding on the secondary side and realize a compact and highly reliable high voltage transformer.

It is sectional drawing (A) and front view (B) of line I-I of the coil bobbin of the high voltage transformer according to one Embodiment of this invention. It is an enlarged sectional view which shows an example of the winding layer structure of the secondary side split winding in the high voltage transformer by this embodiment. It is an enlarged view of one winding layer in FIG. It is a side view which shows an example of the high voltage transformer by this embodiment. It is a block diagram which shows an example of the high voltage power supply circuit using the high voltage transformer by this embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the components described in the following embodiments are merely examples, and the technical scope of the present invention is not limited to them.

1. 1. Configuration The high-voltage transformer according to one embodiment of the present invention comprises a tubular coil bobbin and a rod-shaped soft magnetic core (ferrite core) inserted into the cylinder of the coil bobbin. Hereinafter, the laminated structure of the insulated copper wire (enamel wire) wound around the coil bobbin will be described in detail.

As illustrated in FIG. 1, the coil bobbin 100 in the present embodiment is formed of an insulating resin, and has a tubular portion 101 having a length L and a thickness d, and a plurality of cylinder portions 101 having a height H and a thickness d on the outer periphery of the tubular portion 101. It has a partition plate D ₀ to D _{n + 1} . The through hole 102 of the tubular portion 101 has a square shape with Hd on one side, and a rod-shaped core is arranged therein. In FIG. 1, the cross section of the through hole 102 is rectangular, but the cross section is not limited to this and may be a circular cross section.

Of the plurality of partition plates D ₀ to D _{n + 1} , the primary winding region 103 is between the partition plates D _n and D _{n + 1} , which are adjacent to each other at intervals wp, and the secondary winding region is between the partition plates D ₀ and D _n . 104. The primary winding P is wound in the primary winding region 103 at the number of turns tp. The partition plates D ₀ to D _{n + 1} may also have a circular shape instead of a rectangular shape.

The secondary winding region 104 is further divided by the partition plates D ₁ to D _n-1 , and is divided between the partition plates Di _-1 and Di ( _i = 1, ..., N) adjacent to each other at the interval ws. Winding _Si is wound. The split winding S _i is wound by taking over the enamel wire from the split winding S _i-1 in the previous stage through the crossover groove of the partition plate D _i-1 , and is similarly wound from the split winding S _{i + 1} . It is wound sequentially up to _Sn . Assuming that the number of turns of the split winding _Si is td turns, the total number of turns ts of the secondary winding region 104 is (td × n) turns.

For example, the length L of the coil bobbin 100 is about 100 to 150 mm, the interval wp is about 5 mm, the primary side winding number tp is about 24 to 48 turns, the secondary side winding number ts is about 5000 to 10000 turns, and the split winding S. The number of turns td of _i is about 350 to 600 turns. Next, the laminated winding structure of the arbitrary split winding _Si will be described in detail with reference to FIGS. 2 and 3.

2. 2. Laminated winding structure As illustrated in FIG. 2, the split winding S _i having the number of turns td is an insulating paint layer between the partition plates Di _-1 and Di from the bottom surface on the tubular portion 101 for each predetermined number of sensitizations _tdd . The enamel wire is wound sequentially through V, but the enamel wire is taken over from the split winding S _i-1 in the previous stage through the crossover 105 of the partition plate D _i-1 , and is insulated and protected by the insulating layer 106 on the side surface. Guided to the low side. The insulating layer 106 is provided to prevent dielectric breakdown due to a potential difference between the enamel wire inherited from the previous stage and the split winding _Si . Insulation tape can be used for the insulation 106.

As illustrated in FIG. 3, the split winding _Si with the number of turns td is wound via the insulating coating layer V every predetermined number of turns tdd. The insulating coating layer V is formed by applying a liquid insulating resin, and a high-frequency varnish is used as an example. Hereinafter, the distance ws ₌ 5 mm between the adjacent partition plates Di _-1 and Di, the height H of the partition plate D is 6.75 mm, the diameter φc of the enamel wire used for winding is 0.16 mm, and the predetermined winding of each layer is performed. A specific winding procedure will be described assuming that the number of turns tdd is approximately 100 turns and the total number of turns td of the split winding _Si is approximately 500 turns.

First, when the winding of the lowermost layer is wound for tdd = about 100 turns, a high-frequency varnish is applied to the surface thereof and dried to form a high-frequency varnish coating layer V1. Subsequently, the winding is similarly wound on the high frequency varnish coating layer V1 for tdd = about 100 turns, the high frequency varnish is applied to the surface thereof, and the high frequency varnish is dried to form the high frequency varnish coating layer V2. Similarly, while forming the high frequency varnish coating layer V for each winding of approximately 100 turns, the laminated winding step is repeated until the predetermined total number of windings td is reached. The secondary winding is formed by repeating the same laminated winding process on all the split windings _Si on the secondary side. Assuming that the number of turns of each divided winding _Si is dt = 500 turns, four high-frequency varnish coating layers V1 to V4 are formed every 100 turns. Since a winding with a diameter of 0.16 mm is wound for 500 turns while the interval ws = 5 mm of the partition plate, the insulation is improved and the winding is stabilized by forming the high frequency varnish coating layer V every 100 turns. There is an advantage.

As an example, if the number of turns of the secondary split winding S _i is dt = 500 turns, the number of turns of the primary winding P is tp = 24 turns, and the number of turns of the secondary split winding S _i is dt = 500 turns. If the number of divisions on the secondary side is n = 10, the total number of turns of the secondary winding is ts = td × n = 5000 turns. Therefore, when a pulse voltage of 24 V is applied to the primary side of the high voltage transformer using the coil bobbin 100, a high voltage of 24 × (5000/24) = 5000 V can be obtained on the secondary side.

According to the present embodiment, the secondary winding on the high voltage side is divided into a plurality of divided windings S1 to _Sn by the partition plates D ₀ to _Dn , and each divided winding S _i is further divided by a predetermined number of turns _tdd . By being wound through the insulating coating layer V, it is possible to obtain a stable high voltage output in which insulation breakdown is unlikely to occur even at the high voltage as described above, and it is possible to configure a small power supply. can. The number of divisions _n of the divided windings S1 to Sn, the _interval ws of the partition plates, the number of turns dt of each divided winding _Si , and the number of turns dtd forming the insulating coating layer V are the output voltages on the secondary side. And it can be set in consideration of the boosted voltage and the like in each split winding _Si .

3. 3. Example As illustrated in FIG. 4, the high-voltage transformer 200 according to the embodiment of the present invention has a primary terminal 201 connected to the lead wire of the primary winding P and 2 connected to the lead wire of the secondary winding. It is composed of a next-side terminal 202 and a ferrite core 203 arranged in the through hole 102 of the coil bobbin 100 described above. Here, the length L of the coil bobbin 100 is set to 140 mm, and a ferrite core 203 having substantially the same length is prepared. However, a short ferrite core may be connected in series in 4 to 5 stages in the through hole 102 to form the ferrite core 203. In this case, it is also possible to optimize the performance of the high voltage transformer 200 by adjusting the gap between the short ferrite cores.

The primary winding P of the coil bobbin 100 has 24 to 48 turns, the secondary winding is divided into 20 turns, and each divided winding (S ₁ to S ₂₀ ) has 500 turns, for a total of 10000 turns. At that time, each split winding _Si is coated with a high-frequency varnish every 100 turns of a predetermined number of turns to form a high-frequency varnish coating layer V. Finally, a lead wire is attached and terminals 201 and 202 are connected.

When the ferrite core 203 is formed of a short ferrite core having 4 to 5 stages, the gap of the ferrite core is adjusted so that the primary side terminal 201 is energized and a predetermined voltage is obtained at the secondary side terminal 202. You may.

Finally, the high-voltage transformer 200 is placed in a mold case, and the mold material is poured and solidified to complete the process.

4. High-voltage power supply circuit Hereinafter, an example of a high-voltage power supply circuit to which the high-voltage transformer 200 according to the present embodiment is applied will be described. Here, the number of turns of the primary winding P is tp = 24 turns, the number of divisions of the secondary winding is n = 18, the number of turns of the divided winding _Si is dt = 350 turns, and the number of turns of the insulating coating layer V is tdd = 100. By making a turn and applying 24V to the primary side terminal 201, it is assumed that a high voltage of 4200V is generated in the secondary side terminal 202.

As illustrated in FIG. 5, the oscillator 301 having an oscillation frequency of 1 kHz outputs a pulse signal to the pulse amplifier 303 via the AND gate 302. The oscillation frequency of the oscillator 301 may be set to a predetermined frequency within the range of 1 k to 10 kHz. The pulse amplifier 303 applies a pulse voltage of 24 V to the primary terminal 201 of the high voltage transformer 200 according to the pulse signal. The AND gate 302 conducts or cuts off the pulse signal according to the control signal (ON / OFF) from the control unit 304. That is, if the control signal from the control unit 304 is ON, the pulse signal from the oscillator 301 is output to the pulse amplifier 303, and the pulse voltage of 24 V is output from the pulse amplifier 303 to the high voltage transformer 200. If the control signal from the control unit 304 is OFF, the pulse signal from the oscillator 301 is not output to the pulse amplifier 303, and therefore the pulse amplifier 303 does not output the pulse voltage to the high voltage transformer 200.

The control unit 304 sets the control signal to OFF when the alarm signal ALARM is input from the alarm latch control unit 305, and sets the control signal to ON when the alarm signal ALARM is not input.

The secondary side terminal 202 of the high voltage transformer 200 is provided with a current detection unit 306 and a voltage detection unit 307. The upper limit current detection unit 308 detects whether or not the output current of the high voltage transformer 200 exceeds the upper limit, and outputs ALARM to the alarm latch control unit 305 when the upper limit is exceeded. The upper limit voltage detection unit 309 detects whether or not the output voltage exceeds the upper limit voltage, and outputs ALARM to the alarm latch control unit 305 when the output voltage exceeds the upper limit. The lower limit voltage detection unit 310 detects whether or not the output voltage has fallen below the lower limit voltage, and outputs ALARM to the alarm latch control unit 305 when the output voltage falls below the lower limit voltage.

When the alarm latch control unit 305 inputs ALARM from at least one of the upper limit current detection unit 308, the upper limit voltage detection unit 309, and the lower limit voltage detection unit 310, the alarm latch control unit 305 latches the ALARM and cancels the alarm manually or by a predetermined recovery process. The alarm signal ALLAM is output to the control unit 304 until. Therefore, if an excess current flows on the high voltage output side for some reason, or if the output voltage rises or falls abnormally, the primary side input of the high voltage transformer 200 is cut off until it returns to normal. High voltage output stops.

By using the high voltage transformer 200 according to the embodiment of the present invention, stable high voltage output can be obtained without causing dielectric breakdown even at high voltage, and further, when an abnormality (ALARM) is detected, it is immediately possible. Safety can be further enhanced by stopping the output.

The high-voltage transformer 200 according to the present embodiment can be used as a high-voltage power source for forming an electric field in a refrigerated storage that can maintain freshness for a long period of time by storing food or the like in an electric field, and the high-voltage power source can be downsized. Can be promoted.

The present invention is applicable to a high voltage transformer of a power supply circuit that requires a high voltage of about several kV.

100 Coil bobbin 101 Cylinder 102 Through hole 103 Primary winding area 104 Secondary winding area 105 Cross groove 106 Insulation layer 200 High voltage transformer 201 Primary side terminal 202 Secondary side terminal 203 Ferrite core D ₀ to D _{n + 1} Partition plate P Primary winding S ₁ to _Sn Divided winding V, V1 to V3 Insulation coating layer (high frequency varnish coating layer)

Claims (5)

A high-voltage transformer with a cylindrical coil bobbin through which a rod-shaped soft magnetic core penetrates.
The outer circumference of the cylinder portion of the coil bobbin is divided into a primary winding region and a secondary winding region in the longitudinal direction by a plurality of partition plates, and the secondary winding region is further divided into a plurality of divided winding regions. And
Each of the plurality of divided windings is wound through a coating layer made of an insulating paint every predetermined number of turns, and the plurality of divided windings constitute a secondary winding.
A high voltage transformer characterized by that. The high-voltage transformer according to claim 1, wherein the cylinder portion of the coil bobbin and the plurality of partition plates are made of an insulating resin having a constant thickness. The high-voltage transformer according to claim 1 or 2, wherein the coating layer is formed by coating a high-frequency varnish on the windings each time the coating layer is wound a predetermined number of times. The primary winding is wound in the primary winding region for 24 to 48 turns, and each split winding is wound in the secondary winding region for 350 to 500 turns in total for 5000 to 10000 turns, and every 100 turns in each split winding. The high voltage transformer according to any one of claims 1 to 3, wherein the coating layer is formed. One of claims 1 to 4, wherein a pulse voltage of 24 to 48 V is input to both ends of the primary winding to output 4000 to 5000 V to both ends of the secondary winding. High voltage transformer described in.

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