WO2024040274A1 - Shell-type transformer magnetic core - Google Patents

Shell-type transformer magnetic core Download PDF

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Publication number
WO2024040274A1
WO2024040274A1 PCT/VN2023/000007 VN2023000007W WO2024040274A1 WO 2024040274 A1 WO2024040274 A1 WO 2024040274A1 VN 2023000007 W VN2023000007 W VN 2023000007W WO 2024040274 A1 WO2024040274 A1 WO 2024040274A1
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WO
WIPO (PCT)
Prior art keywords
magnetic
transformer
magnetic core
primary
cylinders
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Application number
PCT/VN2023/000007
Other languages
French (fr)
Inventor
Hoang Giang Dinh
Original Assignee
Hoang Giang Dinh
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Application filed by Hoang Giang Dinh filed Critical Hoang Giang Dinh
Publication of WO2024040274A1 publication Critical patent/WO2024040274A1/en

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/24—Magnetic cores
    • H01F27/26—Fastening parts of the core together; Fastening or mounting the core on casing or support
    • H01F27/263—Fastening parts of the core together
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/24—Magnetic cores
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F3/00—Cores, Yokes, or armatures
    • H01F3/10—Composite arrangements of magnetic circuits
    • H01F3/14—Constrictions; Gaps, e.g. air-gaps

Definitions

  • the present invention relates to a shell-type transformer magnetic core to increase efficiency of a transformer. More particularly, it also relates to a shell-type transformer having such a magnetic core.
  • U.S. Patent No. US9230730B2 refers to a type of transformer that has two separate primary and secondary magnetic cores, in which the reluctance of the secondary magnetic core is many times lower than that of the primary core which makes the magnetic field of the secondary winding only goes in its own magnetic core without looping through the primary winding, and at the same time, the magnetic fields of the secondary winding interact with each other to increase the transformer efficiency.
  • the secondary magnetic core is made of ordinary cold-rolled silicone steel, its size could be very large to have a small enough reluctance to "absorb" all the reactive magnetic field.
  • Patent No. KR101701940B1 also discloses a structure that blocks the magnetic field of the secondary winding by the reluctance of the air gap. However, this structure does not completely block the reactive magnetic field. It can only partially reduce the effect of the reactive magnetic field on the primary winding.
  • An object of the present invention is to provide another technical solution for transformers ensuring that the magnetic field of the secondary winding cannot react through the primary winding, thereby reducing the size and increasing the efficiency of the transformers.
  • a shell-type transformer magnetic core comprising: at least one closed primary magnetic core (10) forming a closed primary magnetic circuit, in which the primary magnetic core (10) is to mount a primary winding (50) of a transformer; at least two hollow secondary magnetic cylinders (20) connected by magnetic yokes (30) arranged at their ends, forming a closed secondary magnetic circuit, in which the secondary magnetic cylinder (20) is to mount a secondary winding (60) of the transformer; wherein each closed primary magnetic core (10) is partially enclosed by a corresponding hollow secondary magnetic cylinder (20) and isolated from that secondary magnetic cylinder by a non-magnetic gap (40) having a sufficient size to completely block the magnetic field of the secondary winding from acting on the primary winding.
  • transformer magnetic core according to item [1], wherein the transformer magnetic core has the number of primary magnetic cores (10) less than or equal to the number of secondary magnetic cylinders (20).
  • transformer magnetic core according to item [1] or [2], wherein the transformer magnetic core includes one primary magnetic core (10) and two secondary magnetic cylinders (20).
  • transformer magnetic core according to item [1] or [2], wherein the transformer magnetic core includes two primary magnetic cores (10) and two secondary magnetic cylinders (20).
  • the transformer magnetic core according to any one of items [1] to [6], wherein the secondary magnetic cylinder (20) and the magnetic yoke (30) is composed of flat sheets of magnetic material joined together, preferably the flat sheets made of silicone steel material.
  • each the hollow secondary magnetic cylinder (20) consists of a segment or segments of separate hollow magnetic cylinders stacked on top of each other.
  • the transformer magnetic core according to any one of the previous items, wherein the primary magnetic core (10) and the secondary magnetic cylinders (20) are arranged in a straight line or at right angles to each other.
  • a shell-type transformer comprises a transformer magnetic core according to any one of the previous items.
  • Figures la-le are schematic drawings illustrating a magnetic core of a shell-type transformer and its components according to an embodiment of the invention as an example.
  • FIGs 2a-2b are schematic drawings of the shell-type transformer, according to an embodiment of the present invention, using the transformer magnetic core shown in Figures la-le.
  • FIGS 3a-3b are schematic drawings of the transformer magnetic core of the shell-type transformer and its components according to another example embodiment of the present invention.
  • FIGs 4a-4b are schematic drawings of the shell-type transformer, according to an embodiment of the present invention, using the transformer magnetic core illustrated in Figures 3a-3b.
  • Figures 5a-5f are drawings of different variations of the examplayry transformer magnetic core layout.
  • Figures 6a-6b are schematic drawings of the transformer magnetic core of the shell-type transformer and its components according to another embodiment of the present invention as an example.
  • Figure 7 is a electrical circuit diagram of a shell-type transformer applied in an inverter circuit that converts DC current to AC current, according to an examplary embodiment of the present invention.
  • a magnetic core of a shell-type transformer consists of: at least one closed primary magnetic core 10 forming a closed primary magnetic (magnetic path) circuit, in which the primary magnetic core 10 is for mounting (or winding) a primary winding 50 of the transformer; at least two hollow secondary magnetic cylinders 20 connected by magnetic yokes 30 arranged at their two ends, forming a closed secondary magnetic circuit, wherein the secondary magnetic cylinders 20 are for mounting (or winding) a secondary winding 60 of the transformer; wherein each the hollow primary magnetic core 10 is partially enclosed by the corresponding hollow secondary magnetic cylinder 20 and isolated from that secondary magnetic cylinder by a non-magnetic gap 40 of sufficient size to block completely the secondary winding's magnetic field acts on the primary winding, i.e. the reactive magnetic field of the secondary winding cannot pass through the non-magnetic gap to penetrate the primary magnetic core 10 or the primary winding.
  • Shell-type transformer magnetic core accoding to the invention can have a number of primary magnetic cores 10 less than the number of secondary magnetic cylinders 20.
  • this transformer magnetic core has one primary magnetic core 10 and two secondary magnetic cylinders 20, of which a part of the primary magnetic core 10 is inserted only into voids of one of the secondary magnetic cylinders 20.
  • the transformer magnetic core has one primary magnetic core 10 in the form of the letter El and two secondary magnetic cylinders 20, in which the two outermost branches of the primary magnetic core 10 are inserted in both voids of the two secondary magnetic cylinders 20 respectively.
  • the shell-type transformer core accoding to the invention may have as many primary magnetic cores 10 as the number of secondary magnetic cylinders 20 ( Figures 3a-3b). According to a specific implementation as an example, this core has two primary magnetic cores 10 and two secondary magnetic cylinders 20, where part of each primary magnetic core 10 is inserted into the void of a one of the secondary magnetic cylinders 20 accordingly.
  • the primary magnetic core 10 inserted into the void of the secondary magnetic cylinder 20 is isolated, i.e. there is no physical contact, with the magnetic cylinder by a non-magnetic gap 40 of size a from 0.5 to 10 mm, preferably from 0.5 to 3 mm.
  • the non-magnetic gap 40 is an air gap.
  • the primary magnetic core 10 may be closed and shaped as torus, square, rectangular, or any other suitable shape.
  • Materials for making the primary magnetic core 10 are well known in the art of transformers.
  • the primary magnetic core 10 can be made by joining sheets of silicon steel material (leaves).
  • the secondary magnetic cylinder 20 and the magnetic yoke 30 made of sheets (leaves) of flat magnetic material, such as silicon steel, joined together ( Figures la-le).
  • the secondary magnetic cylinder 20 and the magnetic yoke 30 are made by wrapping the magnetic tape with an amorphous material, thin silicon steel ( Figure 3a-3b) or made by magnetic casting ferrite or nanocrystalline materials.
  • the materials used to manufacture the secondary magnetic cylinder 20 and the magnetic yoke 30 above are well known in the field of transformers.
  • Each the hollow secondary magnetic cylinder 20 can consist of a single segment (as illustrated in Figure la) or multiple separate stacked segments of hollow cylinders (as shown in Figure 3 a).
  • the magnetic yoke 30 is also provided with holes 31 to fit the holes at the ends of the secondary magnetic cylinders 20, so that the primary magnetic core 10 can be inserted through the holes of the secondary magnetic cylinder 20 and magnetic yoke 30 ( Figures la, le and 3a).
  • the magnetic yoke 30 also have an additional hole 31 in the center through which the central branch of the primary magnetic core 10 can be inserted through it ( Figures 6b-6d).
  • the hollow secondary magnetic cylinders 20 are connected by the magnetic yokes 30 to form a closed secondary magnetic core (secondary magnetic circuit). According to one embodiment, it is preferable that the secondary magnetic cylinders 20 of the transformer magnetic core have the same geometrical parameters.
  • a part of primary magnetic core 10 on which the primary winding 50 is mounted can be located outside of the above-mentioned closed secondary magnetic core shown ( Figures la, 2a).
  • the primary magnetic core 10 on which primary winding 50 is mounted can be located inside the closed secondary magnetic core shown ( Figures 5a, 5b).
  • the primary magnetic core 10 on which the primary winding 50 is mounted and the primary magnetic core 10 is inserted into the void of the secondary magnetic post 20 is formed in a primary magnetic cylindrical form.
  • the primary magnetic core 10 and the secondary magnetic core can be aligned ( Figures lb and 3b) or offset, preferably perpendicular to each other ( Figures 5a-5b).
  • the present invention provides an shelltype transformer consisting of a magnetic core in any of the embodiments mentioned above.
  • this transformer consists of the primary winding 50 mounted on the primary magnetic core 10 without being inserted into the secondary magnetic cylinder 20, the secondary winding 60 is mounted on the secondary magnetic cylinder 20 which has a primary magnetic core 10 embedded in it, while the other secondary magnetic cylinder 20 has no secondary winding.
  • this transformer consists of two primary windings 50 mounted on respective primary magnetic core 10 without being inserted within the secondary magnetic cylinder 20, two secondary windings 60 are mounted on the two secondary magnetic cylinders 20 respectively to which a primary magnetic core 10 is inserted.
  • the primary winding 50 is connected to an external power source.
  • the secondary winding 60 is connected to the load Zt.
  • the power supply to the primary winding 50 can be any voltage level and the output of the secondary winding 60 can also be set to any voltage level that is appropriate for the intended use.
  • the secondary windings 60 are mounted on the secondary magnetic cylinders 20 have the same geometrical and physical parameters, so that they emit equal secondary magnetic fields such that the magnetic field direction of one secondary winding is closed through the other secondary winding in opposite directions.
  • the shell-type transformer accoding to the invention having a primary magnetic core 10 and a secondary magnetic core formed by secondary magnetic cylinders 20 and magnetic yokes 30, these primary and secondary magnetic cores are closed and independent of each other, where a part of each primary magnetic core 10 is surrounded by the corresponding secondary magnetic cylinder 20 and isolated from the secondary magnetic cylinder by a non-magnetic gap 40.
  • the secondary winding 60 induces the magnetic field of the primary winding 50, the secondary winding 60 emits a reactive magnetic field but cannot pass through the non-magnetic gap 40 because it has a very high reluctance.
  • the dimension a of the non-magnetic clearance 40 is adjusted according to the capacity of the transformer, so that its reluctance is high enough to prevent the magnetic field of the secondary winding 60 from passing through the primary magnetic core 10. Therefore, when the power of the load Zt varies from 0 to the maximum, the current capacity of the primary winding 50 is not changed and becomes an inductive circuit, causing the current of the primary winding reaches its maximum value and the magnetic field of the primary winding increases. Thanks to the non-magnetic gap 40, the induced magnetic field from the secondary winding 60 will not pass through the primary magnetic core 10 even if the secondary magnetic core 20 has a reluctance equal to the reluctance of the primary magnetic core 10.
  • the primary winding 50 Since there is no reactive magnetic field passing through the primary winding 50, the primary winding always does not lose resistance, so the primary winding cannot draw more current from the external power source, causing power consumption of the primary winding does not oscillate even when the load power Zt changes suddenly from 0 to maximum value. Because the power consumption of the primary winding is not so fluctuating, the heat generated in the primary winding is reduced, heat loss and eddy current losses are reduced.
  • Figure 7 is a circuit diagram of a pulse transformer (circled) applied in an inverter circuit that converts DC current to a sinusoidal AC current, following an implementation as an example, wherein the pulse transformer has magnetic cores made of materials that can withstand high frequencies, for example ferrite, amorphous or nanocrystalline materials, etc.
  • the above inverter circuit converts the DC current with a voltage of 12V into a sinusoidal AC current to feed the primary winding 50 of the transformer.
  • the output of the secondary winding 60 of the transformer is connected to a load Zt, for example, a light bulb.
  • the present invention provides an alternative solution for a high- efficiency transformer having a closed and independent primary and secondary cores, with a non-magnetic gap between them.
  • the magnetic field emitted by the secondary winding cannot pass through the non-magnetic gap to penetrate the primary winding, even if the reluctance of the secondary magnetic core is equal to the reluctance of the primary magnetic core, so that the size and losses of the machine are reduced, and the efficiency of the machine is increased.
  • both the primary and secondary windings have separate closed magnetic cores, so their magnetic fields only travel through the individual cores of each respective winding. This makes the primary winding just a pure inductor, no external energy is drawn in, heat loss and eddy currents are reduced even if the load power changes from zero to maximum. Because the primary winding is not affected by the reactive magnetic field of the secondary winding, the current of the primary winding is stable, not fluctuating with the load as in traditional transformers, thereby making increase the life of the primary winding.
  • the secondary winding is divided into two windings identical in geometrical and physical parameters, mounted on two opposite secondary magnetic posts of the secondary magnetic core so that for their magnetic fields to interact with each other in opposite directions.
  • This causes the two secondary windings to have an additional magnetic field induced by each other in addition to the magnetic field of the primary coil.
  • This configuration can achieve high current amplification efficiency because no additional external power is required and power is still drawn on both secondary windings supplying power to the load.

Abstract

The invention provides a shell-type transformer magnetic core, comprising: at least one closed primary magnetic core (10) forming a closed primary magnetic circuit, in which the primary magnetic core (10) is to mount a primary winding (50) of a transformer; at least two hollow secondary magnetic cylinders (20) connected by magnetic yokes (30) arranged at their ends, forming a closed secondary magnetic circuit, in which the secondary magnetic cylinder (20) is to mount the secondary winding (60) of the transformer; wherein each closed primary magnetic core (10) is partially enclosed by a corresponding hollow secondary magnetic cylinder (20) and isolated from that secondary magnetic cylinder by a non-magnetic gap (40) having a sufficient size to completely block the magnetic field of the secondary winding from acting on the primary winding (50).

Description

SHELL-TYPE TRANSFORMER MAGNETIC CORE
FIELD OF THE INVENTION
The present invention relates to a shell-type transformer magnetic core to increase efficiency of a transformer. More particularly, it also relates to a shell-type transformer having such a magnetic core.
BACKGROUND OF THE INVENTION
Traditional technology transformers have only one primary winding and one secondary winding on the same single magnetic core. When the magnetic field emitted by the primary winding loops to the secondary winding, the secondary winding induces the magnetic field of the primary winding and emits a reactive magnetic field back to the primary winding, causing the resistance of the winding primary to be reduced, so the primary winding must be compensated for power from an external power supply, causing the efficiency of the transformer to be reduced.
U.S. Patent No. US9230730B2 refers to a type of transformer that has two separate primary and secondary magnetic cores, in which the reluctance of the secondary magnetic core is many times lower than that of the primary core which makes the magnetic field of the secondary winding only goes in its own magnetic core without looping through the primary winding, and at the same time, the magnetic fields of the secondary winding interact with each other to increase the transformer efficiency. However, if the secondary magnetic core is made of ordinary cold-rolled silicone steel, its size could be very large to have a small enough reluctance to "absorb" all the reactive magnetic field.
Patent No. KR101701940B1 also discloses a structure that blocks the magnetic field of the secondary winding by the reluctance of the air gap. However, this structure does not completely block the reactive magnetic field. It can only partially reduce the effect of the reactive magnetic field on the primary winding.
SUMMARY OF THE INVENTION
An object of the present invention is to provide another technical solution for transformers ensuring that the magnetic field of the secondary winding cannot react through the primary winding, thereby reducing the size and increasing the efficiency of the transformers.
To achieve the above object, in accordance with one aspect of the invention, there is provided:
[1], a shell-type transformer magnetic core, comprising: at least one closed primary magnetic core (10) forming a closed primary magnetic circuit, in which the primary magnetic core (10) is to mount a primary winding (50) of a transformer; at least two hollow secondary magnetic cylinders (20) connected by magnetic yokes (30) arranged at their ends, forming a closed secondary magnetic circuit, in which the secondary magnetic cylinder (20) is to mount a secondary winding (60) of the transformer; wherein each closed primary magnetic core (10) is partially enclosed by a corresponding hollow secondary magnetic cylinder (20) and isolated from that secondary magnetic cylinder by a non-magnetic gap (40) having a sufficient size to completely block the magnetic field of the secondary winding from acting on the primary winding.
[2]. The transformer magnetic core according to item [1], wherein the transformer magnetic core has the number of primary magnetic cores (10) less than or equal to the number of secondary magnetic cylinders (20).
[3]. The transformer magnetic core according to item [1] or [2], wherein the transformer magnetic core includes one primary magnetic core (10) and two secondary magnetic cylinders (20).
[4]. The transformer magnetic core according to item [1] or [2], wherein the transformer magnetic core includes two primary magnetic cores (10) and two secondary magnetic cylinders (20).
[5]. The transformer magnetic core according to any one of the previous claims, wherein the non-magnetic gap (40) has a size of 0.5 to 10 mm.
[6], The transformer magnetic core according to any one of items [1] to [5], wherein non-magnetic gap (40) is an air gap.
[7]. The transformer magnetic core according to any one of items [1] to [6], wherein the secondary magnetic cylinder (20) and the magnetic yoke (30) is composed of flat sheets of magnetic material joined together, preferably the flat sheets made of silicone steel material.
[8], The transformer magnetic core according to any one of items [1] to [6], wherein the secondary magnetic cylinder (20) and the magnetic yoke (30) are made by wrapping magnetic tapes with amorphous, thin silicon steel, or made by casting from nanocrystalline or ferritic materials.
[9]. The transformer magnetic core according to any one of the previous items, wherein each the hollow secondary magnetic cylinder (20) consists of a segment or segments of separate hollow magnetic cylinders stacked on top of each other.
[10]. The transformer magnetic core according to any one of the previous items, wherein the primary magnetic core (10) and the secondary magnetic cylinders (20) are arranged in a straight line or at right angles to each other.
[11], The transformer magnetic core according to any one of the previous items, wherein the secondary magnetic cylinders (20) have the same parameters.
According to another aspect, the invention provides: [12], a shell-type transformer comprises a transformer magnetic core according to any one of the previous items.
BRIEFT DISCRIPTION OF THE DRAWINGS
Figures la-le are schematic drawings illustrating a magnetic core of a shell-type transformer and its components according to an embodiment of the invention as an example.
Figures 2a-2b are schematic drawings of the shell-type transformer, according to an embodiment of the present invention, using the transformer magnetic core shown in Figures la-le.
Figures 3a-3b are schematic drawings of the transformer magnetic core of the shell-type transformer and its components according to another example embodiment of the present invention.
Figures 4a-4b are schematic drawings of the shell-type transformer, according to an embodiment of the present invention, using the transformer magnetic core illustrated in Figures 3a-3b.
Figures 5a-5f are drawings of different variations of the examplayry transformer magnetic core layout.
Figures 6a-6b are schematic drawings of the transformer magnetic core of the shell-type transformer and its components according to another embodiment of the present invention as an example.
Figure 7 is a electrical circuit diagram of a shell-type transformer applied in an inverter circuit that converts DC current to AC current, according to an examplary embodiment of the present invention.
DETAILED DESCRIPTION OF EMBODIMENTS
Hereafter, preferred embodiments of magnetic cores and shell-type transformers according to the aspects of the present invention are described in more detail based on the accompanying drawings. However, it is believed that the scope of the invention is not limited to the preferred embodiments described below as an illustrative example of the invention, and it should be understood that the scope of the invention includes all their modifications and other equivalent changes.
As shown in Figures 1-5, a magnetic core of a shell-type transformer consists of: at least one closed primary magnetic core 10 forming a closed primary magnetic (magnetic path) circuit, in which the primary magnetic core 10 is for mounting (or winding) a primary winding 50 of the transformer; at least two hollow secondary magnetic cylinders 20 connected by magnetic yokes 30 arranged at their two ends, forming a closed secondary magnetic circuit, wherein the secondary magnetic cylinders 20 are for mounting (or winding) a secondary winding 60 of the transformer; wherein each the hollow primary magnetic core 10 is partially enclosed by the corresponding hollow secondary magnetic cylinder 20 and isolated from that secondary magnetic cylinder by a non-magnetic gap 40 of sufficient size to block completely the secondary winding's magnetic field acts on the primary winding, i.e. the reactive magnetic field of the secondary winding cannot pass through the non-magnetic gap to penetrate the primary magnetic core 10 or the primary winding.
Shell-type transformer magnetic core accoding to the invention can have a number of primary magnetic cores 10 less than the number of secondary magnetic cylinders 20. According to a specific embodiment as an example (Figure la- lb), this transformer magnetic core has one primary magnetic core 10 and two secondary magnetic cylinders 20, of which a part of the primary magnetic core 10 is inserted only into voids of one of the secondary magnetic cylinders 20. According to another specific embodiment as an example (Figure 6a-6b), the transformer magnetic core has one primary magnetic core 10 in the form of the letter El and two secondary magnetic cylinders 20, in which the two outermost branches of the primary magnetic core 10 are inserted in both voids of the two secondary magnetic cylinders 20 respectively.
The shell-type transformer core accoding to the invention may have as many primary magnetic cores 10 as the number of secondary magnetic cylinders 20 (Figures 3a-3b). According to a specific implementation as an example, this core has two primary magnetic cores 10 and two secondary magnetic cylinders 20, where part of each primary magnetic core 10 is inserted into the void of a one of the secondary magnetic cylinders 20 accordingly.
As shown in Figures lb and 3b and magnified in Figure 1c, the primary magnetic core 10 inserted into the void of the secondary magnetic cylinder 20 is isolated, i.e. there is no physical contact, with the magnetic cylinder by a non-magnetic gap 40 of size a from 0.5 to 10 mm, preferably from 0.5 to 3 mm. As an example implementation, the non-magnetic gap 40 is an air gap.
The primary magnetic core 10 may be closed and shaped as torus, square, rectangular, or any other suitable shape. Materials for making the primary magnetic core 10 are well known in the art of transformers. As an example implementation, the primary magnetic core 10 can be made by joining sheets of silicon steel material (leaves).
The secondary magnetic cylinder 20 and the magnetic yoke 30 made of sheets (leaves) of flat magnetic material, such as silicon steel, joined together (Figures la-le). As an alternative implementation, the secondary magnetic cylinder 20 and the magnetic yoke 30 are made by wrapping the magnetic tape with an amorphous material, thin silicon steel (Figure 3a-3b) or made by magnetic casting ferrite or nanocrystalline materials. The materials used to manufacture the secondary magnetic cylinder 20 and the magnetic yoke 30 above are well known in the field of transformers. Each the hollow secondary magnetic cylinder 20 can consist of a single segment (as illustrated in Figure la) or multiple separate stacked segments of hollow cylinders (as shown in Figure 3 a).
The magnetic yoke 30 is also provided with holes 31 to fit the holes at the ends of the secondary magnetic cylinders 20, so that the primary magnetic core 10 can be inserted through the holes of the secondary magnetic cylinder 20 and magnetic yoke 30 (Figures la, le and 3a). In the case of primary magnetic core 10 with the letter El, the magnetic yoke 30 also have an additional hole 31 in the center through which the central branch of the primary magnetic core 10 can be inserted through it (Figures 6b-6d).
The hollow secondary magnetic cylinders 20 are connected by the magnetic yokes 30 to form a closed secondary magnetic core (secondary magnetic circuit). According to one embodiment, it is preferable that the secondary magnetic cylinders 20 of the transformer magnetic core have the same geometrical parameters.
As an examplary implementation, a part of primary magnetic core 10 on which the primary winding 50 is mounted can be located outside of the above-mentioned closed secondary magnetic core shown (Figures la, 2a). As an examplary alternative implementation the primary magnetic core 10 on which primary winding 50 is mounted can be located inside the closed secondary magnetic core shown (Figures 5a, 5b). As another examplary implementation, the primary magnetic core 10 on which the primary winding 50 is mounted and the primary magnetic core 10 is inserted into the void of the secondary magnetic post 20 is formed in a primary magnetic cylindrical form.
As an example implementation, the primary magnetic core 10 and the secondary magnetic core can be aligned (Figures lb and 3b) or offset, preferably perpendicular to each other (Figures 5a-5b). According to another aspect, the present invention provides an shelltype transformer consisting of a magnetic core in any of the embodiments mentioned above.
As an examplary implementation, as shown in Figures 2a-2b, this transformer consists of the primary winding 50 mounted on the primary magnetic core 10 without being inserted into the secondary magnetic cylinder 20, the secondary winding 60 is mounted on the secondary magnetic cylinder 20 which has a primary magnetic core 10 embedded in it, while the other secondary magnetic cylinder 20 has no secondary winding.
As an examplary alternative implementation, as shown in Figures 4a- 4b, this transformer consists of two primary windings 50 mounted on respective primary magnetic core 10 without being inserted within the secondary magnetic cylinder 20, two secondary windings 60 are mounted on the two secondary magnetic cylinders 20 respectively to which a primary magnetic core 10 is inserted.
The primary winding 50 is connected to an external power source. The secondary winding 60 is connected to the load Zt. The power supply to the primary winding 50 can be any voltage level and the output of the secondary winding 60 can also be set to any voltage level that is appropriate for the intended use.
According to an examplary implementation of a transformer shown in Figures 4a-4b, the secondary windings 60 are mounted on the secondary magnetic cylinders 20 have the same geometrical and physical parameters, so that they emit equal secondary magnetic fields such that the magnetic field direction of one secondary winding is closed through the other secondary winding in opposite directions.
The shell-type transformer accoding to the invention having a primary magnetic core 10 and a secondary magnetic core formed by secondary magnetic cylinders 20 and magnetic yokes 30, these primary and secondary magnetic cores are closed and independent of each other, where a part of each primary magnetic core 10 is surrounded by the corresponding secondary magnetic cylinder 20 and isolated from the secondary magnetic cylinder by a non-magnetic gap 40. When the secondary winding 60 induces the magnetic field of the primary winding 50, the secondary winding 60 emits a reactive magnetic field but cannot pass through the non-magnetic gap 40 because it has a very high reluctance. Furthermore, since the secondary cylinders 20 are closed by the magnetic yokes 30 arranged at their ends, in the transformer as shown in Figures 4a-4b, the magnetic field generated by the secondary windings 60 only travels in the secondary magnetic core and only interacts with each other.
The dimension a of the non-magnetic clearance 40 is adjusted according to the capacity of the transformer, so that its reluctance is high enough to prevent the magnetic field of the secondary winding 60 from passing through the primary magnetic core 10. Therefore, when the power of the load Zt varies from 0 to the maximum, the current capacity of the primary winding 50 is not changed and becomes an inductive circuit, causing the current of the primary winding reaches its maximum value and the magnetic field of the primary winding increases. Thanks to the non-magnetic gap 40, the induced magnetic field from the secondary winding 60 will not pass through the primary magnetic core 10 even if the secondary magnetic core 20 has a reluctance equal to the reluctance of the primary magnetic core 10. Since there is no reactive magnetic field passing through the primary winding 50, the primary winding always does not lose resistance, so the primary winding cannot draw more current from the external power source, causing power consumption of the primary winding does not oscillate even when the load power Zt changes suddenly from 0 to maximum value. Because the power consumption of the primary winding is not so fluctuating, the heat generated in the primary winding is reduced, heat loss and eddy current losses are reduced.
Figure 7 is a circuit diagram of a pulse transformer (circled) applied in an inverter circuit that converts DC current to a sinusoidal AC current, following an implementation as an example, wherein the pulse transformer has magnetic cores made of materials that can withstand high frequencies, for example ferrite, amorphous or nanocrystalline materials, etc. The above inverter circuit converts the DC current with a voltage of 12V into a sinusoidal AC current to feed the primary winding 50 of the transformer. The output of the secondary winding 60 of the transformer is connected to a load Zt, for example, a light bulb.
Effects of invention
The present invention provides an alternative solution for a high- efficiency transformer having a closed and independent primary and secondary cores, with a non-magnetic gap between them. As a result, the magnetic field emitted by the secondary winding cannot pass through the non-magnetic gap to penetrate the primary winding, even if the reluctance of the secondary magnetic core is equal to the reluctance of the primary magnetic core, so that the size and losses of the machine are reduced, and the efficiency of the machine is increased.
Furthermore, both the primary and secondary windings have separate closed magnetic cores, so their magnetic fields only travel through the individual cores of each respective winding. This makes the primary winding just a pure inductor, no external energy is drawn in, heat loss and eddy currents are reduced even if the load power changes from zero to maximum. Because the primary winding is not affected by the reactive magnetic field of the secondary winding, the current of the primary winding is stable, not fluctuating with the load as in traditional transformers, thereby making increase the life of the primary winding.
On the other hand, according to an embodiment in which the secondary winding is divided into two windings identical in geometrical and physical parameters, mounted on two opposite secondary magnetic posts of the secondary magnetic core so that for their magnetic fields to interact with each other in opposite directions. This causes the two secondary windings to have an additional magnetic field induced by each other in addition to the magnetic field of the primary coil. This configuration can achieve high current amplification efficiency because no additional external power is required and power is still drawn on both secondary windings supplying power to the load.

Claims

WHAT IS CLAIMED IS
1. A shell-type transformer magnetic core, comprising: at least one closed primary magnetic core (10) forming a closed primary magnetic circuit, in which the primary magnetic core (10) is to mount a primary winding (50) of a transformer; at least two hollow secondary magnetic cylinders (20) connected by magnetic yokes (30) arranged at their ends, forming a closed secondary magnetic circuit, in which the secondary magnetic cylinder (20) is to mount a secondary winding (60) of the transformer; wherein each the closed primary magnetic core (10) is partially enclosed by one corresponding hollow secondary magnetic cylinder (20) and isolated from that secondary magnetic cylinder by a non-magnetic gap (40) having a sufficient size to completely block the magnetic field of the secondary winding from acting on the primary winding.
2. The transformer magnetic core according to claim 1, wherein the transformer magnetic core has a number of primary magnetic cores (10) less than or equal to the number of secondary magnetic cylinders (20).
3. The transformer magnetic core according to claim 1 or 2, wherein the transformer magnetic core includes one primary magnetic core (10) and two secondary magnetic cylinders (20).
4. The transformer magnetic core according to claim 1 or 2, wherein the transformer magnetic core includes two primary magnetic cores (10) and two secondary magnetic cylinders (20).
5. The transformer magnetic core according to any one of the previous claims, wherein the non-magnetic gap (40) has a size of 0.5 to 10 mm.
6. The transformer magnetic core according to any one of claims 1-5, wherein the non-magnetic gap (40) is an air gap.
7. The transformer magnetic core according to any one of claims 1-6, wherein the secondary magnetic cylinder (20) and the magnetic yoke (30) is composed of flat sheets of magnetic material joined together, preferably the flat sheets made of silicone steel material.
8. The transformer magnetic core according to any one of claims 1-6, wherein the secondary magnetic cylinder (20) and the magnetic yoke (30) are made by wrapping magnetic tapes with amorphous, thin silicon steel, or made by casting from nanocrystalline or ferritic materials.
9. The transformer magnetic core according to any one of the previous claims, wherein each the hollow secondary magnetic cylinder (20) consists of a segment or segments of separate hollow magnetic cylinders stacked on top of each other.
10. The transformer magnetic core according to any one of the previous claims, wherein the primary magnetic core (10) and the secondary magnetic cylinders (20) are arranged in a straight line or at right angles to each other.
11. The transformer magnetic core according to any one of the previous claims, wherein the secondary magnetic cylinders (20) have the same parameters.
12. A shell-type transformer comprises a transformer magnetic core according to any one of the previous claims.
PCT/VN2023/000007 2022-08-15 2023-06-30 Shell-type transformer magnetic core WO2024040274A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009010003A1 (en) * 2007-07-14 2009-01-22 Gang Liu Power coupler
US9230730B2 (en) 2013-03-07 2016-01-05 Thane C. Heins Bi-toroidal topology transformer
KR101701940B1 (en) 2015-05-28 2017-02-02 주식회사 피앤이솔루션 Three phase transformer which can function as inductor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009010003A1 (en) * 2007-07-14 2009-01-22 Gang Liu Power coupler
US9230730B2 (en) 2013-03-07 2016-01-05 Thane C. Heins Bi-toroidal topology transformer
KR101701940B1 (en) 2015-05-28 2017-02-02 주식회사 피앤이솔루션 Three phase transformer which can function as inductor

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