A low leakage current small arc driving transformer

Abstract

The utility model provides a low leakage current small arc driving transformer, including insulating shell, magnetic core, the magnetic core is EE type magnetic core, and is equipped with the framework in the magnetic core, and the winding group is wound on the framework in the magnetic core, and the winding group includes the primary winding, secondary winding that winds on the framework in proper order, and the primary winding is set with the framework, is equipped with the shielding layer between the primary winding and secondary winding, first insulating layer and second insulating layer are equipped with between the shielding layer with the primary winding, secondary winding respectively, the magnetic core periphery is covered with insulating shell, the insulating shell inner wall is equipped with the annular recess that extends along the axial direction, fills the arc extinguishing gas in the annular recess, the outer surface of insulating shell is equipped with the heat dissipation fin. The utility model has the beneficial effect that: through the shielding layer, restrains common mode leakage current, arc extinguishing gas quickly extinguishes arc, current -limiting module restrains overvoltage and overcurrent, realizes low leakage current, small arc, high reliability's driving transformer.

Description

Technical Field

[0001] This invention belongs to the field of electronic transformer technology, and is particularly suitable for a low leakage current, small arc drive transformer. Background Technology

[0002] In high-frequency, high-voltage drive power supplies, transformers must not only achieve voltage transformation but also suppress leakage current and arc discharge. Existing technologies mainly suffer from the following shortcomings: large distributed capacitance between primary and secondary windings leads to high common-mode leakage current and excessive EMI; concentrated electric field at core joints and winding ends easily generates partial discharge and continuous arc, shortening insulation life; and winding insulation is easily broken down under overvoltage and overcurrent impacts. Utility Model Content

[0003] To address the above problems, the purpose of this utility model is to provide a low leakage current, small arc drive transformer, which features low leakage current, small arc, and high reliability.

[0004] The technical solution of this utility model is: a low leakage current, small arc-driven transformer, comprising an insulating shell and a magnetic core. The magnetic core is an EE type magnetic core, and a skeleton is provided inside the magnetic core. A winding assembly is wound on the skeleton inside the magnetic core. The winding assembly includes a primary winding and a secondary winding wound sequentially on the skeleton. The primary winding is set close to the skeleton. A shielding layer is provided between the primary winding and the secondary winding. A first insulating layer and a second insulating layer are respectively provided between the shielding layer and the primary winding and the secondary winding. The shielding layer is copper foil. The outer periphery of the magnetic core is covered with an insulating shell. The inner wall of the insulating shell has an axially extending annular groove filled with arc-extinguishing gas. The outer surface of the insulating shell is provided with heat dissipation fins. The primary winding is connected in series with a current-limiting module, which is located inside the shell. The current-limiting module is encapsulated in an epoxy resin potting body. The current-limiting module includes a PTC thermistor and a varistor connected in parallel and then connected in series with a thermal fuse.

[0005] Furthermore, the magnetic core is a ferrite core.

[0006] Furthermore, the shielding layer is connected to the grounding pin via conductive adhesive.

[0007] Furthermore, the primary winding has 10 to 50 turns, and the secondary winding has 100 to 500 turns.

[0008] Furthermore, the primary and secondary windings are wound in opposite directions to cancel out leakage flux.

[0009] Furthermore, the arc-quenching gas is sulfur hexafluoride, nitrogen, or carbon dioxide.

[0010] Furthermore, the insulating shell is made of polytetrafluoroethylene or polyimide.

[0011] Furthermore, the cross-section of the annular groove is semi-circular or rectangular.

[0012] Furthermore, the bottom of the insulating housing is provided with mounting holes for fixing the transformer.

[0013] The advantages and positive effects of this utility model are as follows: due to the adoption of the above technical solution, the shielding layer forms a Faraday cage after grounding, which significantly reduces the common mode leakage current and further reduces the EMI value; the arc extinguishing gas cools down and deionizes rapidly when the arc is generated, shortening the arc duration to the microsecond level; the current limiting module clamps the varistor when overvoltage occurs and limits the current with high resistance of the PTC thermistor when overcurrent occurs, providing dual protection. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model.

[0015] In the picture: 1. Insulating outer shell 2. Magnetic core 3. Frame 4. Winding assembly; 5. Annular groove; 6. Heat dissipation fins. 7. Current limiting module 8. Mounting holes Detailed Implementation

[0016] like Figure 1 As shown, the technical solution of this utility model includes an insulating shell 1 and a magnetic core 2. The magnetic core is an EE type magnetic core, and a skeleton 3 is provided inside the magnetic core. A winding group 4 is wound on the skeleton 3 inside the magnetic core 2. The winding group 4 includes a primary winding and a secondary winding wound sequentially on the skeleton. The primary winding is set in close contact with the skeleton 3. A shielding layer is provided between the primary winding and the secondary winding. A first insulating layer and a second insulating layer are respectively provided between the shielding layer and the primary winding and the secondary winding. The shielding layer is copper foil. The outer periphery of the magnetic core 2 is covered by the insulating shell 1. The inner wall of the insulating shell 1 has an axially extending annular groove 5. The annular groove 5 is filled with arc-quenching gas. The outer surface of the insulating shell 1 is provided with heat dissipation fins 6. The primary winding is connected in series with a current limiting module 7, which is located inside the shell 1. The current limiting module 7 is encapsulated in an epoxy resin potting body. The current limiting module includes a PTC thermistor and a varistor connected in parallel and then connected in series with a thermal fuse.

[0017] In this embodiment, the magnetic core 2 is a ferrite magnetic core.

[0018] In this embodiment, the shielding layer is connected to the grounding pin via conductive adhesive.

[0019] In this embodiment, the primary winding has 10 to 50 turns, and the secondary winding has 100 to 500 turns.

[0020] In this embodiment, the winding directions of the primary winding and the secondary winding are opposite to cancel out leakage flux.

[0021] In this embodiment, the arc-quenching gas is sulfur hexafluoride, nitrogen, or carbon dioxide.

[0022] In this embodiment, the insulating shell 1 is made of polytetrafluoroethylene or polyimide.

[0023] In this embodiment, the cross-section of the annular groove 5 is semi-circular or rectangular.

[0024] In this embodiment, the bottom of the insulating shell 1 is provided with mounting holes 8 for fixing the transformer.

[0025] The working process of this example is as follows: During operation, if a high-voltage spike occurs on the secondary winding side, the varistor quickly conducts to clamp the circuit. If overcurrent persists, the resistance of the PTC thermistor jumps to limit the current, and the thermal fuse melts at 130°C, cutting off the power supply. If an arc occurs between the windings, the SF6 gas in the annular groove forms a cooling channel within microseconds, extinguishing the arc. The shielding layer diverts common-mode interference current to ground, reducing leakage current.

[0026] The above description provides a detailed account of one embodiment of the present invention. However, this description is merely a preferred embodiment and should not be construed as limiting the scope of the present invention. All equivalent variations and improvements made within the scope of the claims of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A low leakage current, small arc-driven transformer, characterized in that: The device includes an insulating shell and a magnetic core. The magnetic core is an EE-type magnetic core with a skeleton inside. A winding assembly is wound around the skeleton inside the magnetic core. The winding assembly includes a primary winding and a secondary winding wound sequentially around the skeleton. The primary winding is fitted to the skeleton. A shielding layer is provided between the primary winding and the secondary winding. A first insulating layer and a second insulating layer are respectively provided between the shielding layer and the primary winding and the secondary winding. The shielding layer is made of copper foil. The magnetic core is covered with an insulating shell. The inner wall of the insulating shell has an axially extending annular groove filled with arc-quenching gas. The outer surface of the insulating shell has heat dissipation fins. The primary winding is connected in series with a current-limiting module, which is located inside the shell. The current-limiting module is encapsulated in an epoxy resin potting compound. The current-limiting module includes a PTC thermistor and a varistor connected in parallel and then connected in series with a thermal fuse.

2. The low leakage current, small arc drive transformer according to claim 1, characterized in that: The magnetic core is a ferrite core.

3. The low leakage current, small arc drive transformer according to claim 1, characterized in that: The grounding pin is connected to the shielding layer via conductive adhesive.

4. The low leakage current, small arc drive transformer according to claim 1, characterized in that: The primary winding has 10 to 50 turns, and the secondary winding has 100 to 500 turns.

5. A low leakage current, small arc drive transformer according to claim 1, characterized in that: The primary and secondary windings are wound in opposite directions.

6. A low leakage current, small arc drive transformer according to claim 1, characterized in that: The arc-quenching gas is sulfur hexafluoride, nitrogen, or carbon dioxide.

7. A low leakage current, small arc drive transformer according to claim 1, characterized in that: The insulating shell is made of polytetrafluoroethylene or polyimide.

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