JP6278153B1 - Transformer - Google Patents

Abstract

Kind Code: A1 A transformer using a limited number of litz wires is provided by reducing the types of litz wires used for primary and secondary windings. A transformer includes a core having a first leg and a second leg, a cylindrical first coil and a third coil disposed on the first leg, and a second coil. Including a cylindrical second coil 106 and a fourth coil 110 arranged on the leg, the first to fourth coils are formed of litz wire, the first and second coils are connected in parallel, and the third and third coils The four coils are connected in series, the first and second coils have the same number of turns, the same shape and the same size, and the third and fourth coils have the same number of turns, the same shape and the same size. Thereby, a transformer can be configured by connecting litz wires in parallel without causing an imbalance in the current value, and in a high-frequency transformer, an increase in resistance value due to the skin effect can be suppressed. [Selection] Figure 3

Description

  The present invention relates to a voltage converting transformer, and more particularly to a high frequency transformer used in a DC-DC converter or the like.

  In a transformer, a plurality of coils may be connected in parallel to form a primary coil or a secondary coil. When a plurality of conductors are wound in parallel to form a transformer coil, load currents (unbalanced currents) of different magnitudes flow through the conductors due to differences in impedance of the conductors (coils). When an unbalanced current flows, the load loss increases more than when a uniform current flows. As a method for preventing this, a technique (dislocation) is known in which, when winding conductors in parallel, the conductors cross each other at a predetermined position and the positions are switched.

  For example, Patent Document 1 and Patent Document 2 below disclose dislocation of a primary coil and a secondary coil at the center in the axial direction as shown in FIG.

  On the other hand, in order to use at high frequency, a technique using a litz wire for a winding of a transformer is known (see Patent Documents 3 and 4 below). Patent Document 3 discloses that a transformer is formed by using a litz wire whose peripheral surface is covered with a flexible insulating material for the primary winding and the secondary winding.

  Patent Document 4 discloses that a primary winding and a secondary winding, which are litz wires, are alternately arranged in the winding axis direction and wound to correspond to 1: 1 to form a transformer. . In addition, it is disclosed that either a primary winding or a secondary winding is connected in parallel and the other is connected in series to form a step-up transformer or a step-down transformer.

Japanese Patent Laid-Open No. 2000-21625 JP 2007-157987 A Japanese Utility Model Publication No. 63-201316 JP 2012-243880 A

  In a high-frequency transformer, it is preferable to use a litz wire in the winding to suppress an increase in resistance value due to the skin effect, but an induced voltage is induced by a slight unbalance in the spatial position, and a large circulating current loss ( Since stray loss occurs, it is difficult to use in parallel connection, and it has always been necessary to use one litz wire. Therefore, it is necessary to use litz wires having different cross-sectional areas according to current values of different specifications, and different types of litz wires may be used for the primary coil and the secondary coil, increasing the types of members. There was a problem in producing a small variety of various types of transformers.

  The above problems cannot be solved by Patent Documents 1 to 4. Patent Documents 1 and 2 do not disclose the use of a litz wire for the winding.

  Patent Document 3 discloses that a litz wire is used, but does not disclose that a plurality of coils formed by winding a litz wire are connected in parallel. Patent Document 3 aims to solve the problem that alignment winding is difficult when a litz wire is used and the winding work is complicated, and Patent Document 3 does not recognize the above problem.

  Patent Document 4 discloses that one of a primary winding and a secondary winding using a litz wire is connected in parallel. However, Patent Document 4 aims to increase the coupling coefficient of the coil and reduce the amount of heat generation. Patent Document 4 does not recognize the above problem in the first place. Moreover, in patent document 4, since a coil is formed by winding primary windings and secondary windings alternately in the winding axis direction so as to correspond to 1: 1, a core having a gap is used. When the positions of the two coils and the gap are shifted, the leakage magnetic flux in the gap portion is unbalanced between the two coils, and a circulating current flows between the two coils connected in parallel, resulting in loss. There are problems and difficult to manufacture.

  Accordingly, an object of the present invention is to provide a transformer using a limited type of litz wire by reducing the types of litz wire used for the primary winding and the secondary winding.

  The transformer according to the first aspect of the present invention has a first leg portion and a second leg portion, and is formed in a cylindrical shape by winding a core forming a closed magnetic circuit and a first winding. The first coil disposed around the leg and the second winding are wound to form a cylinder, and the second coil disposed around the second leg and the third winding are wound. And is formed in a cylindrical shape, is coaxially formed with the first coil and is disposed around the first leg, and a fourth winding is wound into a cylindrical shape, and is coaxial with the second coil. And a fourth coil disposed around the second leg. The first winding and the second winding are the same type of litz wire, and the third winding and the fourth winding are the same type of litz wire. The first coil and the second coil are connected in parallel to each other, and the third coil and the fourth coil are connected in series to each other. The first winding forming the first coil and the second winding forming the second coil are wound so that when the first coil and the second coil are energized, a magnetic field circulating in the closed magnetic path is formed. The third winding forming the third coil and the fourth winding forming the fourth coil form a magnetic field that circulates in the closed magnetic path when the third coil and the fourth coil are energized. It is wound to be. The first coil is formed such that the wound first winding is adjacent to the axial direction of the first coil, and the second coil is adjacent to the wound second winding in the axial direction of the second coil. The third coil is formed such that the third winding to be wound is adjacent to the axial direction of the third coil. The fourth coil is formed such that the wound fourth winding is adjacent to the axial direction of the fourth coil, the first coil and the second coil have the same number of turns, the same shape and the same size, The three coils and the fourth coil have the same number of turns, the same shape, and the same size. The first coil and the third coil have overlapping projections in the axial direction, or the projection in the axial direction of one coil includes the projection in the axial direction of the other coil, and the second coil and the fourth coil. Are arranged so that the mutual positional relationship is the same as the mutual positional relationship of the first coil and the third coil.

  Thereby, a litz wire can be connected in parallel and a transformer can be constituted, without producing imbalance in an electric current value. Moreover, in a high frequency transformer, the increase in resistance value by a skin effect can be suppressed.

  Preferably, the core further includes a third leg portion, and the transformer is formed in a cylindrical shape by winding the fifth winding, and a fifth coil disposed around the third leg portion, A sixth coil wound around the third leg and coaxially formed with the fifth coil. The fifth winding and the sixth winding are litz wires, the fifth coil is connected in parallel to the first coil and the second coil, and the sixth coil is connected in series to the third coil and the fourth coil. . The fifth winding forming the fifth coil is wound so as to form a magnetic field that circulates in the closed magnetic path when the first coil, the second coil, and the fifth coil are energized. The sixth winding forming the coil is wound so that a magnetic field circulating in the closed magnetic path is formed when the third coil, the fourth coil, and the sixth coil are energized. The fifth coil is formed such that the wound fifth winding is adjacent to the fifth coil in the axial direction, and the sixth coil is wound adjacent to the sixth coil in the axial direction. To be formed. The fifth coil has the same number of turns, the same shape and the same size as the first coil, and the sixth coil has the same number of turns, the same shape and the same size as the third coil. The fifth coil and the sixth coil are arranged such that the mutual positional relationship is the same as the mutual positional relationship of the first coil and the third coil.

  Thereby, since the number of coils connected in parallel increases, it becomes easy to increase the output current value.

  More preferably, the core further includes a fourth leg, and the transformer is formed in a cylindrical shape by winding the seventh winding, and the seventh coil is disposed around the fourth leg. An eighth coil wound around the fourth leg and coaxially formed with the seventh coil. The seventh winding and the eighth winding are litz wires, the seventh coil is connected in parallel to the first coil, the second coil, and the fifth coil, and the eighth coil is the third coil, the fourth coil, and A sixth coil is connected in series. The seventh winding forming the seventh coil is wound so that a magnetic field circulating in the closed magnetic path is formed when the first coil, the second coil, the fifth coil, and the seventh coil are energized. The eighth winding forming the eighth coil is wound so that a magnetic field circulating in the closed magnetic path is formed when the third coil, the fourth coil, the sixth coil, and the eighth coil are energized. Has been. The seventh coil is formed such that the wound seventh winding is adjacent in the axial direction of the seventh coil, and the eighth coil is adjacent to the eighth winding in the axial direction of the eighth coil. To be formed. The seventh coil has the same number of turns, the same shape and the same size as the first coil, and the eighth coil has the same number of turns, the same shape and the same size as the third coil. The seventh coil and the eighth coil are arranged so that the mutual positional relationship is the same as the mutual positional relationship of the first coil and the third coil.

  Thereby, since the number of coils connected in parallel increases, it becomes easier to increase the output current value.

  The transformer according to the second aspect of the present invention includes a plurality of transformers according to the first aspect. The first coil and the second coil are all connected in parallel to each other, and the third coil and the fourth coil are all connected in series to each other. The first coil and the second coil are all the same number of turns, the same shape and the same size, and the third coil and the fourth coil are all the same number of turns, the same shape and the same size. The mutual positional relationship between the coils and the mutual positional relationship between the second coil and the fourth coil are all the same.

  Thereby, since the number of coils connected in parallel increases, it becomes easy to increase the output current value.

  Preferably, the first winding and the third winding are the same type of litz wire.

  Thereby, all the coils can be formed with one type of litz wire, and it is not necessary to stock a plurality of types of litz wires, which is economical.

  More preferably, the core is composed of two U-shaped members having the same size, and the ends of the two U-shaped members are arranged to face each other with a predetermined distance therebetween to form a gap. .

  As a result, it is possible to suppress the magnetic bias of the core, to suppress the saturation of the magnetic flux of the core, and to form a stable high-frequency transformer.

  According to the present invention, since litz wires can be used in parallel connection, it is not necessary to use a large litz wire in order to increase the current value. Can be manufactured. Therefore, it does not have a lot of unnecessary inventory, is economical, and is suitable for the production of a small variety of various types of transformers.

It is a figure which shows the dislocation of the winding in the conventional transformer. It is a perspective view showing a schematic structure of a transformer concerning an embodiment of the invention. It is sectional drawing which shows the transformer which concerns on embodiment of this invention. It is sectional drawing which shows the coil formed in the multilayer. It is sectional drawing which shows the state from which the height of a primary coil and a secondary coil differs. It is a figure which shows the example of the core from which the position of a gap differs from FIG. It is sectional drawing which shows the transformer which concerns on the 1st modification using two cores. It is sectional drawing which shows the transformer which concerns on the 2nd modification which has arrange | positioned the coil to three leg parts of a core. It is sectional drawing which shows the transformer which concerns on the 3rd modification which has arrange | positioned the coil to four leg parts of a core.

  In the following embodiments, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  2 and 3, the high-frequency transformer 100 according to the embodiment of the present invention includes a core 102, a first coil 104, a second coil 106, a third coil 108, and a fourth coil 110. Yes. Between the first coil 104 and the third coil 108, and between the second coil 106 and the fourth coil 110, a first insulating sheet 112 formed by an electric insulating member (hereinafter also simply referred to as an insulating member) and A second insulating sheet 114 is disposed. In FIG. 2, the connections and terminals between the coils shown in FIG. 3 are not shown.

  The core 102 is made of a ferromagnetic material (eg, ferrite, amorphous alloy, nanocrystalline soft magnetic material, etc.). The core 102 may be formed of a high-frequency wound core.

  The first coil 104, the second coil 106, the third coil 108, and the fourth coil 110 are formed using the same type of litz wire. A litz wire is an electric wire formed by combining a plurality of conductive thin wires covered with an insulating member. Here, the same type means products of the same part number manufactured mainly by the same manufacturer, but is not limited thereto, and also means similar products (equivalent products manufactured regardless of the same manufacturer or different manufacturers). To do.

  The core 102 includes a first U-shaped core 120 and a second U-shaped core 122. The first U-shaped core 120 and the second U-shaped core 122 have the same cross-sectional shape (for example, a square) and the same cross-sectional area. Opposing portions of the first U-shaped core 120 and the second U-shaped core 122 are arranged at a predetermined interval, and form a first gap 128 and a second gap 130. The first gap 128 and the second gap 130 are air gaps. An insulating member (such as a glass epoxy resin plate) may be disposed in the first gap 128 and the second gap 130.

  The first coil 104 is formed in a cylindrical shape by winding a litz wire a predetermined number of times (N1 times) around the columnar first leg portion 124 of the core 102. Similarly, the second coil 106 is formed in a cylindrical shape by winding a litz wire N1 times around the columnar second leg 126 of the core 102. The first coil 104 and the second coil 106 are formed such that the radii of the cylinders are substantially equal and the heights of the cylinders are also substantially equal.

  The third coil 108 is formed in a cylindrical shape around the first coil 104 by winding a litz wire N2 times. Similarly, the fourth coil 110 is formed in a cylindrical shape by winding a litz wire N2 times around the second coil 106. The first coil 104 and the third coil 108 are formed coaxially. Similarly, the second coil 106 and the fourth coil 110 are formed coaxially. The third coil 108 and the fourth coil 110 are formed so that the radii of the cylinders are substantially equal and the heights of the cylinders are also substantially equal. The cylindrical axes of the first coil 104 and the third coil 108 are arranged so as to coincide with the central axis of the first leg portion 124, and the cylindrical axes of the second coil 106 and the fourth coil 110 are the second leg portion. Preferably, it is arranged so as to coincide with the central axis of 126.

  An end 148 that is one end of the first coil 104 and an end 152 that is one end of the second coil 106 are connected to the first terminal 140. An end 150 that is the other end of the first coil 104 and an end 154 that is the other end of the second coil 106 are connected to the second terminal 142. That is, the first coil 104 and the second coil 106 are connected in parallel.

  An end 156 that is one end of the third coil 108 is connected to the third terminal 144, and an end 158 that is the other end of the third coil 108 is connected to an end 160 that is one end of the fourth coil 110. An end 162 that is the other end of the fourth coil 110 is connected to the fourth terminal 146. That is, the third coil 108 and the fourth coil 110 are connected in series.

  The windings of the third coil 108 and the fourth coil 110 are wound in opposite directions so that a magnetic field is formed in the direction of circulation in the core 102 when energized. For example, when a voltage higher than the fourth terminal 146 is applied to the third terminal 144 on the basis of the voltage of the fourth terminal 146, the third coil 108 and the fourth coil 110 indicate, for example, the arrows in FIG. A magnetic field is formed in the opposite direction. The winding direction of the first coil 104 with respect to the third coil 108 and the winding direction of the second coil 106 with respect to the fourth coil 110 are arbitrary, but the winding of the first coil 104 is opposite to that of the third coil 108. If it is wound in the direction, the winding of the second coil 106 is wound in the opposite direction to the fourth coil 110. If the winding of the first coil 104 is wound in the same direction as the third coil 108, the winding of the second coil 106 is wound in the same direction as the fourth coil 110. That is, the first coil 104 and the second coil 106 are wound in opposite directions so that when energized, a magnetic field is formed in a direction circulating in the core 102. Therefore, when an alternating voltage that changes with time is applied between the third terminal 144 and the fourth terminal 146, an alternating current flows through the third coil 108 and the fourth coil 110, and the first terminal 140 and the fourth terminal 110 are caused by electromagnetic induction. An induced voltage (AC voltage) is generated at the second terminal 142, and an AC voltage is generated between the first terminal 140 and the second terminal 142. That is, induced voltage is generated in the first coil 104 and the second coil 106 which are the secondary coils using the third coil 108 and the fourth coil 110 as primary coils.

  When an AC power source is connected between the third terminal 144 and the fourth terminal 146 and a load is connected between the first terminal 140 and the second terminal 142, the windings of the first coil 104 and the third coil 108 are mutually connected. Since the mutual inductance is large and a load current flows through the first coil 104, the third coil 108 has an ampere turn due to the load current flowing through the first coil 104. A current of a magnitude that cancels (the product of the number of turns of the coil and the amperage of the current passing therethrough) flows. Similarly, since the windings of the second coil 106 and the fourth coil 110 are arranged close to each other and are wound coaxially, the mutual inductance is large, and the fourth coil 110 includes the second coil 106. A current of a magnitude that cancels the ampere turn due to the load current flowing in the current flows.

  As described above, the first coil 104, the second coil 106, the third coil 108, and the fourth coil 110 are formed using the same type of litz wire, and the first coil 104 and the second coil 106 are the same. The third coil 108 and the fourth coil 110 are formed by winding the same number of turns (N2 times). Further, the first coil 104 and the second coil 106 formed in a cylindrical shape have substantially the same size, and the third coil 108 and the fourth coil 110 formed in a cylindrical shape also have substantially the same size. . Further, the third coil 108 and the fourth coil 110 are arranged in the same positional relationship with respect to the first coil 104 and the second coil 106, respectively, and the first U-shaped core 120 and the second U-shaped core 122 are Have the same cross-sectional shape and the same cross-sectional area. Therefore, the impedances of the first coil 104 and the second coil 106 are substantially equal, and the impedances of the third coil 108 and the fourth coil 110 are substantially equal. Further, the leakage inductance between the first coil 104 and the third coil 108 is substantially equal to the leakage inductance between the second coil 106 and the fourth coil 110. Therefore, in the high frequency transformer 100, a voltage generated between the end portions 148 and 150 that are both ends of the first coil 104 and a voltage generated between the end portions 152 and 154 that are both ends of the second coil 106. Are substantially equal to each other, and there is no imbalance in the current values flowing through the first coil 104 and the second coil 106.

  Since the first coil 104 and the second coil 106 are connected in parallel and the third coil 108 and the fourth coil 110 are connected in series, these coils seem to satisfy N1≈N2 (including the case where N1 = N2). If the first terminal 140 and the second terminal 142 are formed, a voltage that is approximately ½ of the voltage between the third terminal 144 and the fourth terminal 146 is generated between the first terminal 140 and the second terminal 142. Between the terminals 142, a current that is approximately twice the current value that flows between the third terminal 144 and the fourth terminal 146 flows.

  Since the first coil 104, the second coil 106, the third coil 108, and the fourth coil 110 are formed of litz wires, the high-frequency transformer 100 is changed to a device equipped with a high-speed switching element such as a DC-DC converter. Even if it is used, an increase in resistance due to the skin effect can be suppressed.

  If the coils connected in parallel are formed with a single wire having a large cross-sectional area in order to pass a large current, stray loss is large. On the other hand, as described above, as shown in FIGS. 2 and 3, when a transformer is formed by connecting two low-voltage side coils in parallel using a litz wire, all of the low-voltage side coils are formed. Loss can be reduced as compared with the case of forming with one coil. In the examples of FIGS. 2 and 3, it was found that the calculation is reduced to about 0.77 times (= 1 / 1.3 times).

  In addition, since the low voltage side coils (first coil 104 and second coil 106) and the high voltage side coils (third coil 108 and fourth coil 110) are formed of the same type of litz wire, It is not necessary to use different types of litz wires for the primary coil and the secondary coil, and it is not necessary to prepare and stock a plurality of litz wires, which is economical.

  In the case of a transformer for high power (high frequency transformer 200 kVA) that is switched at a high frequency of several kHz or more, for example, about 10,000 thin wires with a diameter of less than 0.1 mm covered with an insulating member are combined. A litz wire having an outer diameter of about 10 mm is used.

  In the above, the ratio of the number of turns N2 of the secondary coil (low voltage side coil, for example, the first coil 104) to the number of turns N1 of the primary coil (high voltage side coil, for example, the third coil 108) of each leg (ratio of turns) r = Although the case where N2 / N1 is about 1 (when the current densities of the primary coil and the secondary coil are substantially equal) has been described, the present invention is not limited to this. The first coil 104 and the second coil 106 may have the same number of turns and the third coil 108 and the fourth coil 110 may have the same number of turns, and the first coil 104 and the third coil 108 may have the same number of turns (the second coil 106 and the fourth coil 106). 110 turns) may be different.

  The turn ratio r can be changed, for example, in a range of r = 1 / 1.5 to 1.5 / 1 (= about 0.67 to 1.5). For example, when r = 1 / 1.5 and the number of turns of each secondary coil is 10 turns, the number of turns of each primary coil is 15 turns in the transformer shown in FIGS. . In this case, if the current value flowing through the primary coil is 100 A, a current of 150 A flows through each secondary coil, and the total current value output from the secondary coils connected in parallel is 300 A. 2 and 3, the total current value of the secondary coil is about 2 / r times the current value of the primary coil using the turn ratio r of each leg. Therefore, the turn ratio r of each leg may be determined in consideration of the current value flowing through the primary coil in accordance with the desired total current value of the secondary coil.

  Although FIG. 2 shows the case where the first coil 104, the second coil 106, the third coil 108, and the fourth coil 110 are formed in one layer, the present invention is not limited to this. As shown in FIG. 4, it may be formed in a plurality of layers. In FIG. 4, the first coil 104 and the third coil 108 are each formed in two layers, but may be formed in three or more layers. The number of layers of the first coil 104 and the number of layers of the second coil 106 are preferably equal, and the number of layers of the third coil 108 and the number of layers of the fourth coil 110 are preferably equal.

  Moreover, although the above demonstrated the case where the height (the height as a cylinder) of the 1st coil 104, the 2nd coil 106, the 3rd coil 108, and the 4th coil 110 was all equal, it is not limited to this. If the heights of the first coil 104 and the second coil 106 are equal and the heights of the third coil 108 and the fourth coil 110 are equal, the heights of the first coil 104 and the third coil 108 (the second coil 106 and the second coil 106). The height of the four coils 110 may be different as shown in FIG. In FIG. 5, the height h <b> 1 of the third coil 108 is larger than the height h <b> 2 of the first coil 104 (h <b> 1> h <b> 2), and the third coil 108 is disposed so as to cover the first coil 104. That is, the first coil 104 and the third coil 108 are arranged so that the projection of the third coil 108 in the axial direction includes the projection of the first coil 104 in the axial direction. The height h1 of the third coil 108 may be lower than the height h2 of the first coil 104 (h1 <h2). In that case, the third coil 108 is disposed so as to overlap the first coil 104. That is, the first coil 104 and the third coil 108 are arranged so that the projection of the third coil 108 in the axial direction is included in the projection of the first coil 104 in the axial direction. Even when the heights of the first coil 104 and the second coil 106 are different, the first coil 104 and the third coil 108 are arranged so that the center of the first coil 104 and the center of the third coil 108 are substantially the same position. It is preferable to arrange. The same applies to the second coil 106 and the fourth coil 110.

  In addition, the first coil 104, the second coil 106, the third coil 108, and the fourth coil 110 may be formed in a plurality of layers as long as the above-described conditions regarding the height are satisfied.

  In the above, the case where the first coil 104, the second coil 106, the third coil 108, and the fourth coil 110 are all formed of the same type of litz wire has been described, but the present invention is not limited to this. If the first coil 104 and the second coil 106 are formed of the same type of litz wire, and the third coil 108 and the fourth coil 110 are formed of the same type of litz wire, the first coil 104 and the third coil 108 are used. (The second coil 106 and the fourth coil 110) may be formed of different types of litz wires.

  In FIG. 3, the position of the gap is located at the center of each coil, but is not limited to this. The position of the gap is arbitrary. The two gaps may be formed at asymmetric positions. For example, you may use the core in which the gap was formed in the position as shown to (A) or (B) of FIG.

  Although the case where the 1st coil 104, the 2nd coil 106, the 3rd coil 108, and the 4th coil 110 were formed in the above was explained above, it is not limited to this. The first coil 104, the second coil 106, the third coil 108, and the fourth coil 110 may have a cylindrical shape formed by winding a winding along a side surface of a core having a rectangular cross section.

Further, the core shape is arbitrary, and any shape may be used as long as it forms the closed magnetic circuit and the plurality of legs on which the plurality of coils are arranged have the same size and shape. The cross-sectional shape of the core is also arbitrary, and may be rectangular or circular as shown in FIG.
Although the case where the primary coil (the 3rd coil 108 and the 4th coil 110) is formed outside the secondary coil (the 1st coil 104 and the 2nd coil 106) was explained above, it is not limited to this. Secondary coils (first coil 104 and second coil 106) may be formed outside the primary coils (third coil 108 and fourth coil 110).

(First modification)
Although the high frequency transformer 100 using one core 102 has been described above, the present invention is not limited to this. A plurality of high-frequency transformers 100 may be used to form a transformer.

  With reference to FIG. 7, the high-frequency transformer 200 includes two high-frequency transformers 100 described above. In the two high-frequency transformers 100, all primary coils (third coil 108 and fourth coil 110) are connected in series with each other, and all secondary coils (first coil 104 and second coil 106) are mutually connected. Connected in parallel. Therefore, when the number of turns of the first coil 104, the second coil 106, the third coil 108, and the fourth coil 110 is equal, the current value between the first terminal 140 and the second terminal 142 of the high-frequency transformer 200 is the third terminal. It becomes four times the current value between 144 and the fourth terminal 146.

(Second modification)
In the above description, the case where the coil is formed on the two legs (the first leg 124 and the second leg 126) of the core 102 has been described, but the present invention is not limited to this. Referring to FIG. 8, in the high-frequency transformer 300, in addition to the first leg 124 and the second leg 126, the third leg 302 is provided with the primary as in the first coil 104 and the third coil 108. A coil and a secondary coil are formed. All of the three primary coils constituting the high-frequency transformer 300 are connected in series, and when energized, form a magnetic flux circulating in the core 102 as indicated by an arrow, for example. The three secondary coils constituting the high-frequency transformer 300 are all connected in parallel, and form a magnetic flux that circulates in the core 102 when energized.

  Therefore, when all the turns of each primary coil and each secondary coil are equal, the current value between the first terminal 140 and the second terminal 142 of the high-frequency transformer 300 is between the third terminal 144 and the fourth terminal 146. Three times the current value.

(Third Modification)
Referring to FIG. 9, in high-frequency transformer 400, first coil 104 and third coil 108 are added to fourth leg 402 in addition to first leg 124, second leg 126 and third leg 302. The primary coil and the secondary coil are formed in the same manner as in FIG. The four primary coils constituting the high-frequency transformer 400 are all connected in series, and when energized, form a magnetic flux that circulates in the core 102 as indicated by an arrow, for example. The four secondary coils constituting the high-frequency transformer 400 are all connected in parallel, and form a magnetic flux that circulates in the core 102 when energized.

  Therefore, when all the turns of each primary coil and each secondary coil are equal, the current value between the first terminal 140 and the second terminal 142 of the high-frequency transformer 400 is between the third terminal 144 and the fourth terminal 146. Four times the current value.

  As described above, using the turn ratio r of the primary coil and the secondary coil arranged in each leg, the total current value of the secondary coil is the primary in the case of the high-frequency transformer of FIGS. The current value of the coil is about 4 / r times, and in the case of the high-frequency transformer of FIG. 8, the current value of the primary coil is about 3 / r times. What is necessary is just to determine the turn ratio r of each leg part in consideration of the electric current value which flows into a primary coil according to the total electric current value of the desired secondary coil.

  As mentioned above, although this invention was demonstrated by describing embodiment, above-described embodiment is an illustration, Comprising: This invention is not necessarily restricted only to above-described embodiment. The scope of the present invention is indicated by each claim of the claims after taking into account the description of the detailed description of the invention, and all modifications within the meaning and scope equivalent to the wording described therein are included. Including.

100, 200, 300, 400 High-frequency transformer 102 Core 104 First coil 106 Second coil 108 Third coil 110 Fourth coil 112 First insulating sheet 114 Second insulating sheet 120 First U-shaped core 122 Second U-shaped core 124 1st leg 126 2nd leg 128 1st gap 130 2nd gap 140 1st terminal 142 2nd terminal 144 3rd terminal 146 4th terminal 148, 150, 152, 154, 156, 158, 160, 162 end Part 302 Third leg 402 Fourth leg

Claims (5)

A core having a first leg and a second leg and forming a closed magnetic path;
A first coil wound around and formed in a cylindrical shape and disposed around the first leg;
A second coil wound around and formed in a cylindrical shape and disposed around the second leg;
A third coil wound around and formed into a cylindrical shape, and arranged around the first leg coaxially with the first coil;
A fourth coil wound around and formed into a cylindrical shape, and arranged around the second leg coaxially with the second coil,
The first winding and the second winding are the same type of litz wire,
The third winding and the fourth winding are the same type of litz wire,
The first coil and the second coil are connected in parallel to each other;
The third coil and the fourth coil are connected in series with each other,
The first winding forming the first coil and the second winding forming the second coil are magnetic fields that circulate in the closed magnetic circuit when the first coil and the second coil are energized. Is wound to form
The third winding forming the third coil and the fourth winding forming the fourth coil are magnetic fields that circulate in the closed magnetic path when the third coil and the fourth coil are energized. Is wound to form
The first coil is formed such that the first winding to be wound is adjacent to the axial direction of the first coil;
The second coil is formed such that the second winding to be wound is adjacent to the axial direction of the second coil,
The third coil is formed such that the third winding to be wound is adjacent to the axial direction of the third coil,
The fourth coil is formed so that the fourth winding to be wound is adjacent to the axial direction of the fourth coil,
The first coil and the second coil have the same number of turns, the same shape and the same size,
The third coil and the fourth coil have the same number of turns, the same shape and the same size,
The first coil and the third coil have axial projections overlapping, or the axial projection of one coil includes the axial projection of the other coil,
The transformer, wherein the second coil and the fourth coil are arranged so that the mutual positional relationship is the same as the mutual positional relationship of the first coil and the third coil. The core further includes a third leg,
A fifth coil wound around and formed in a cylindrical shape, arranged around the third leg,
A sixth coil wound around and formed in a cylindrical shape, and arranged around the third leg coaxially with the fifth coil;
The fifth winding and the sixth winding are litz wires,
The fifth coil is connected in parallel to the first coil and the second coil,
The sixth coil is connected in series to the third coil and the fourth coil,
The fifth winding forming the fifth coil is wound so that a magnetic field circulating in the closed magnetic path is formed when the first coil, the second coil, and the fifth coil are energized. Has been
The sixth winding forming the sixth coil is wound so that a magnetic field circulating in the closed magnetic path is formed when the third coil, the fourth coil, and the sixth coil are energized. Has been
The fifth coil is formed so that the fifth winding to be wound is adjacent to the axial direction of the fifth coil,
The sixth coil is formed such that the sixth winding to be wound is adjacent to the axial direction of the sixth coil,
The fifth coil has the same number of turns, the same shape and the same size as the first coil,
The sixth coil has the same number of turns, the same shape and the same size as the third coil,
2. The fifth coil and the sixth coil are arranged such that a mutual positional relationship is the same as a mutual positional relationship of the first coil and the third coil. Transformer described in. A plurality of transformers according to claim 1 are provided,
The first coil and the second coil are all connected in parallel to each other,
The third coil and the fourth coil are all connected in series with each other,
The first coil and the second coil are all the same number of turns, the same shape and the same size,
The third coil and the fourth coil are all the same number of turns, the same shape and the same size,
The mutual positional relationship between the first coil and the third coil, and the mutual positional relationship between the second coil and the fourth coil are all the same.   The transformer according to any one of claims 1 to 3, wherein the first winding and the third winding are the same type of litz wire. The core is composed of two U-shaped members of the same size,
5. The transformer according to claim 1, wherein the end portions of the two U-shaped members are arranged to face each other with a predetermined distance apart from each other, thereby forming a gap. vessel.

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