JP2010199223A - Pulse transformer and pulsed power supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve the reduction in size of a pulse transformer simultaneously with reduction of leak inductance, and also to achieve the prevention of breakdown thereof simultaneously with the reduction of leak inductance. <P>SOLUTION: The pulse transformer includes a magnetic core, and primary winding and secondary winding composed of low-voltage electric wires concentrically wound on the magnetic core. The primary winding and the secondary winding are uniformly and closely wound, and the wound primary winding and secondary winding are molded by silicon potting. Since the field intensity in a space part between the windings can be kept high by the molding of the primary winding and the secondary winding by the silicon potting, dielectric breakdown between the windings can be prevented. Further, since the coating thickness of the low-voltage electric wire is smaller than that of a high-voltage electric wire, the windings can be evenly and closely wound, and the leak inductance can be thus reduced. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pulse power supply device, and more particularly to a pulse power supply device that generates a high-voltage pulse on the secondary side of a pulse transformer.

  2. Description of the Related Art A pulse power supply device is known in which energy charged in a capacitor is transferred via a pulse transformer and a switching element to generate a high voltage pulse from the secondary side of the pulse transformer.

  FIG. 2 is a circuit diagram for explaining an example of a conventional pulse power supply device and a sectional view of a pulse transformer.

  In the circuit diagram shown in FIG. 2A, the pulse power supply device 10 includes a charging power supply 12, energy transfer capacitors 13 and 16, a semiconductor switch 14, a reactor 15, and a pulse transformer 11. The energy transfer capacitor 13 is connected in parallel to the series connection of the reactor 15, the primary winding of the pulse transformer 11, and the semiconductor switch 14. When the semiconductor switch 14 is closed after charging the energy transfer capacitor 13 with the charging power source 12, energy is transferred from the energy transfer capacitor 13 through the primary winding of the reactor 15 and the pulse transformer 11 and the closed circuit of the semiconductor switch 14, A high pulse voltage is induced in the secondary winding of the pulse transformer 11.

  2B, the pulse transformer 11 includes magnetic cores 11a and 11b, a primary winding 11e, and a secondary winding 11d, and is between the primary winding 11e and the secondary winding 11d. In order to prevent dielectric breakdown, interlayer insulation 11c is provided. The shape of the core is not limited to the illustrated EI type, but may be a toroidal type, an EE type, or the like. (See Patent Document 1)

  The pulse transformer is applied to various fields such as a lithography light source, an ozone generator, and water treatment. For example, Non-Patent Document 1 and Patent Documents 2 and 3 show those applied to a high-intensity discharge lamp or the like. Patent Document 4 discloses an ISDN pulse transformer.

  In Patent Document 1, problems such as a slow rise of the pulse and resonance of output voltage due to leakage inductance and stray capacitance are pointed out due to the influence of leakage inductance due to magnetic coupling failure between the primary winding and the secondary winding. In order to solve this problem, a configuration using a coaxial cable for winding of a pulse transformer has been proposed.

  Non-Patent Document 1 proposes a winding method for reducing the size of the pulse transformer and increasing the space factor of the secondary winding in order to ensure withstand voltage performance.

  In Patent Document 2, it is proposed to reduce the number of turns in order to reduce the resistance of the secondary winding and avoid the temperature rise due to the resistance component. At this time, in order to reduce the resistance without reducing the output, it is proposed that the leakage magnetic flux should be suppressed as a closed magnetic circuit configuration of the magnetic core. It has also been shown that an unsaturated polyester resin or a liquid crystal polymer resin is used to fix the winding to the magnetic core.

  Patent Document 3 discloses that the insulation between the pulse transformer and the connector is secured by filling the pulse transformer, the connector, and the discharge preventing member in the case with silicon resin.

Japanese Unexamined Patent Application Publication No. 2004-80908 (see paragraphs 0002 to 0006) JP 2004-207405 A (see paragraphs 0021, 0022, 0047) Japanese Patent Laying-Open No. 2005-285361 (see paragraphs 0002 to 0004) JP 07-201587 A

Matsushita Electric Works, Vol.53, No.2, p97-p103 “High space factor winding method for HID high voltage pulse transformer for automotive use”

  A pulse transformer of a conventional pulse power source is formed by winding a core material. Since this winding generates a high voltage, for example, a high voltage electric wire such as a silicon electric wire is used. The high voltage electric wire is formed by providing an insulating layer on the outer periphery of the conductive material.

  The inventors of the present application have found that problems such as leakage inductance and dielectric breakdown occur in the insulating layer of the pulse transformer.

  First, the problem of leakage inductance will be described. In the pulse transformer, a thick insulating layer is provided around the conductive material of the high voltage electric wire in order to withstand a high voltage. When the insulating layer is thick, the adhesion between the high-voltage electric wire and the core material is lowered, so that the leakage inductance between the high-voltage electric wire and the core material is increased. For example, when the pulse transformer is applied to a magnetic pulse compression circuit, the leakage inductance is increased. In addition to the problem that the rise of the pulse voltage is delayed, the voltage time product of the pulse transformer increases, so the peripheral members are enlarged. Problem arises.

  One way to reduce leakage inductance is to increase the cross-sectional area of the core and reduce the number of windings. In this case, since the cross-sectional area of the core becomes large, there arises a problem that the size of the pulse transformer is increased and the manufacturing cost is increased.

  Further, as another method for reducing the leakage inductance, it is conceivable to perform windings in parallel. Even in this case, there arises a problem that the size of the pulse transformer increases because the windings are arranged in parallel.

  Various countermeasures have been proposed for the above-described leakage inductance problem. For example, regarding leakage inductance, the above-described Patent Document 1 proposes a configuration in which a high-voltage electric wire is a coaxial electric wire with respect to a pulse rising delay problem and an output voltage resonance problem caused by the leakage inductance. Further, in the above-mentioned Patent Document 4, with respect to the problem that leakage inductance increases in order to obtain a high inductance in the ISDN pulse transformer, two pipe-shaped magnetic cores are arranged, and the bifilar winding is centered on the opposite side surfaces. The structure which gives is proposed. However, any of the leakage inductance reduction methods proposed in Patent Documents 1 and 4 has a problem that the size of the pulse transformer increases.

  As described above, the conventional technique for reducing the leakage inductance has a problem that the size of the pulse transformer is increased.

  Next, problems such as dielectric breakdown will be described. The pulse transformer has a problem that dielectric breakdown occurs due to an unequal electric field of air existing between the windings when a high voltage is applied. With respect to the problem of dielectric breakdown, in Patent Document 3, attention is paid to the dielectric breakdown of the connector portion, and the insulation between the pulse transformer and the connector is ensured by filling the case with silicon resin. It has been proposed to prevent the generation of corona discharge by removing an air layer by filling an insulating material between the electrode and the discharge preventing member.

  However, when the technique for preventing dielectric breakdown proposed in Patent Document 3 described above is applied to a pulse transformer, a problem arises in that leakage inductance increases because high-voltage electric wires are used.

  As described above, the conventional pulse transformer has a problem that it is difficult to simultaneously solve the reduction in leakage inductance and the reduction in the size of the pulse transformer.

  Moreover, there is a problem that it is difficult to simultaneously solve the reduction of leakage inductance and the prevention of dielectric breakdown between electric wires.

  Therefore, the present invention aims to solve the above-described conventional problems and simultaneously solve the problem of reducing the leakage inductance and reducing the size of the pulse transformer, and also reducing the leakage inductance and preventing the dielectric breakdown between the wires. It aims at solving simultaneously.

  The pulse transformer of the present invention includes a magnetic core and a primary winding and a secondary winding made of a low-voltage electric wire concentrically applied to the magnetic core. The primary winding and the secondary winding are applied in close contact to reduce leakage inductance, and the applied primary winding and secondary winding are molded by silicon potting. Silicon potting may mold the primary winding and the secondary winding together with the magnetic core.

  In the pulse transformer of the present invention, since the primary winding and the secondary winding are molded by silicon potting, the electric field strength in the space portion of the winding can be kept high, so that dielectric breakdown between the windings is prevented. be able to.

  Further, by molding the winding by silicon potting, a low voltage electric wire can be used without using a high voltage electric wire having a thick high voltage coating. As the low voltage electric wire, a polyester copper wire coated with a polyester resin can be used. Since the thickness of the coating of the low-voltage electric wire such as polyester copper wire is thinner than the thickness of the coating of the high-voltage electric wire, it can be tightly wound. Therefore, the leakage inductance of the winding can be reduced.

  Furthermore, since the polyester copper wire is less expensive than the high-voltage electric wire, the cost of the pulse transformer can be reduced by reducing the cost of the electric wire.

  The pulse transformer of the present invention can reduce the leakage inductance while preventing dielectric breakdown, thereby increasing the number of windings and reducing the size and weight of the pulse transformer.

  This is because, in the pulse transformer, the voltage V has a relationship of V = A · n · (dB / dt) between the cross-sectional area A of the magnetic core, the number of turns n of the electric wire, and the magnetic flux density B. This is because the cross-sectional area A of the core can be reduced by increasing the number of windings n of the wire if it is kept constant.

  Further, the pulse power supply device of the present invention includes a pulse transformer, a capacitor connected in parallel to the primary winding side of the pulse transformer, and an energy transfer path from the capacitor to the primary winding via the reactor. A high voltage pulse induced in the secondary winding of the pulse transformer based on the voltage generated on the primary winding side by the energy transfer path formed by closing the switch. Output. By configuring the pulse power supply device of the present invention using the pulse transformer of the present invention, the pulse power supply device can be reduced in size and weight.

  As described above, according to the pulse power supply device of the present invention, it is possible to simultaneously reduce the leakage inductance and reduce the size of the pulse transformer.

  Moreover, according to the pulse power supply device of the present invention, it is possible to simultaneously realize reduction of leakage inductance and prevention of dielectric breakdown between electric wires.

It is a figure for demonstrating the outline of the 1st, 2nd, 3rd form of the pulse transformer of this invention. It is a circuit diagram for explaining an example of a pulse power supply device, and a sectional view for explaining an example of a pulse transformer.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Hereinafter, a configuration example of the pulse transformer of the present invention will be described with reference to FIG.

[First, second, and third forms of pulse transformer]
First, second, and third embodiments of the pulse transformer of the present invention will be described. FIG. 1 is a diagram for explaining the outline of first, second, and third embodiments of the pulse transformer of the present invention. Below, the 1st, 2nd, 3rd form is demonstrated by pulse transformer 1A, 1B, 1C, respectively.

  In FIG. 1, pulse transformers 1A, 1B, and 1C show another configuration example of an EI type magnetic core. The pulse transformers 1A, 1B, and 1C include a magnetic core 2 composed of an E-type magnetic core portion 2a and an I-type magnetic core portion 2b, and primary windings 3 and secondary applied to the magnetic core portion 2a. A winding 4 and a mold part 5 formed by silicon potting are provided.

  For example, the E-shaped magnetic core portion 2a is formed into a E-shaped cross section by a ferrite core, and the I-shaped magnetic core portion 2b is formed into a I-shaped cross section by a ferrite core. A magnetic circuit is formed by disposing the side of the magnetic core portion 2b so as to face the open end of the mold shape.

  The primary winding 3 and the secondary winding 4 may be a low-voltage electric wire such as a polyester copper wire formed by coating a polyester resin around a copper wire.

  In FIG. 1A, the pulse transformer 1A applies the secondary winding 4 over substantially the entire outer peripheral surface of the E-type magnetic core portion 2a without passing through an insulating bobbin. It is applied to the outside of the secondary winding 4. The primary winding 3 is applied over the entire length where the secondary winding 4 is applied.

  A structure in which the secondary winding 4 is further provided outside the primary winding 3 and the primary winding 3 is sandwiched between the secondary windings 4 may be adopted.

  In FIG. 1B, the pulse transformer 1B applies the primary winding 3 over almost the entire outer peripheral surface of the magnetic core portion 2a without passing through an insulating bobbin, and the secondary winding 4 is primary-wound. Apply to outside of line 3.

  The primary winding 3 may be further provided outside the secondary winding 4 so that the secondary winding 4 is sandwiched between the primary windings 3.

  The primary winding 3 and the secondary winding 4 of the pulse transformers 1A and 1B are applied so as to be concentrically and evenly adhered to the magnetic core portion 2a. This reduces leakage inductance.

  The mold parts 5 of the pulse transformers 1A and 1B insulate the primary winding 3 and the secondary winding 4 provided on the outer periphery of the magnetic core part 2a and fix them to the magnetic core part 2c. The mold part 5 can be formed by filling the magnetic core part 2a with the primary winding 3 and the secondary winding 4, attaching the magnetic core part 2b, and then filling it with silicon resin.

  In FIG. 1C, the pulse transformer 1C is a configuration example in which not only the winding part but also the magnetic core parts 2a and 2b are subjected to silicon potting to form an integral mold part of the pulse transformer.

  According to the pulse transformer of each aspect of the present invention, the winding inductance can be increased because the leakage inductance can be reduced, and thus the voltage time product can be set to a predetermined value even if the area of the magnetic core of the pulse transformer is reduced. The value can be maintained, and the pulse transformer can be reduced in size and weight.

[Pulse power supply configuration]
Each aspect of the pulse transformer of the present invention can be applied to a pulse power supply device. The pulse power supply device can be configured in the same way as the circuit shown in FIG. 2A, and the pulse power supply device is configured by a charging power supply, an energy transfer capacitor, a reactor, a semiconductor switch, and a pulse transformer. Can do.

  The energy transfer capacitor, the primary winding of the reactor and the pulse transformer, and the semiconductor switch are connected in series. With the semiconductor switch open, the energy transfer capacitor is charged by the charging power source, and after the energy transfer capacitor is charged, the semiconductor switch is closed. Based on the voltage generated on the primary winding side by the energy transfer path formed by closing the semiconductor switch, a high voltage pulse voltage is induced in the secondary winding of the pulse transformer.

  According to the pulse power supply device of the present invention, in the generation of a high voltage in the pulse transformer, the primary winding and the secondary winding can obtain a high electric field strength by molding by silicon potting, so that corona discharge can be prevented.

  In addition, since the leakage inductance of the pulse transformer can be reduced and the area of the magnetic core can be reduced, the pulse power supply device can be reduced in size and weight.

  The configuration of the pulse power supply device is an example and is not limited to this configuration.

  The present invention is not limited to the embodiments described above. Various modifications can be made based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

  The pulse power supply device of the present invention can be applied to fields such as a lithography light source, an ozone generator, water treatment, and an igniter.

1A to 1C Pulse transformer 2 Magnetic core 2a Magnetic core part 2b Magnetic core part 3 Primary winding 4 Secondary winding 5 Molding part 10 Pulse power supply device 11 Pulse transformer 11a, 11b Magnetic core 11c Primary winding 11d Secondary winding 11e Interlayer insulation 12 Charging power supply 13, 16 Energy transfer capacitor 14 Semiconductor switch 15 Reactor

Claims (4)

A magnetic core,
A primary winding and a secondary winding applied concentrically to the magnetic core;
The primary winding and the secondary winding are applied by concentrically and evenly attaching a low-voltage electric wire to the magnetic core,
A pulse transformer, wherein at least the applied primary winding and secondary winding are molded by silicon potting.   The pulse transformer according to claim 1, wherein the silicon potting is formed by integrally molding the primary winding and the secondary winding together with a magnetic core.   The pulse transformer according to claim 1 or 2, wherein the low-voltage electric wire is a polyester copper wire coated with a polyester resin. The pulse transformer according to any one of claims 1 to 3,
A capacitor connected in parallel to the primary winding side of the pulse transformer, and a switch provided on the energy transfer path from the capacitor to the primary winding via the reactor,
A pulse power supply that outputs a high voltage pulse induced in a secondary winding of the pulse transformer based on a voltage generated on the primary winding side by an energy transfer path formed by closing the switch. apparatus.