JP2004022721A - Transformer and its manufacturing method, electric power converter and electric power generating equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein when there is a large difference in characteristics of a plurality of primary windings in a switching transformer that is used for a electric power converter and has an extremely large boosting ratio, causing a decrease in power conversion efficiency. <P>SOLUTION: A second winding 107 is wound almost uniformly around a winding body of a winding core. Then, two primary windings 102, 103 are wound adjacent to each of both ends of the winding body, to be connected electrically to nearest terminals arranged at both outsides of the winding body, respectively. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a transformer and a method for manufacturing the transformer, a power converter, and a power generator, and for example, relates to a converter for power generated by a solar cell or the like.
[0002]
[Prior art]
In recent years, DC power generated by solar cells or fuel cells has been converted to AC power by a power converter to address domestic environmental loads (hereinafter referred to as “loads”) and / or commercial power in order to address environmental issues. It is supplied to a system (hereinafter, referred to as “system”), or is converted into a predetermined DC voltage and used for driving a load.
[0003]
In particular, a power converter connected to a solar cell is required to have a small size, a low profile, and a high conversion efficiency so as to match the shape of the solar cell. There is a similar demand for a transformer, which is a main component of the power converter.
[0004]
FIGS. 1 and 2 are diagrams showing a configuration of a switching transformer of a power converter in which a main circuit of the power converter has a general push-pull type switching circuit.
[0005]
1 and 2, primary windings 402 and 403 are windings on the side to which a switching element is connected, and secondary windings 404 and 405 are windings on a side to which a load is connected. When supplying DC power to the load, a full-wave (bridge) type rectifier circuit is used in the transformer shown in FIG. 1, and a full-wave or two-phase half-wave rectifier circuit is used in the transformer shown in FIG.
[0006]
FIG. 3 is a diagram showing a state of a primary winding of the transformer shown in FIGS. When the primary windings 402 and 403 have one turn, as shown in FIG. 3, after connecting one end of the electric wire to the terminal 410 of the bobbin 409, the electric wire is wound around the bobbin 409 once, and the other end of the electric wire is connected to the terminal 411. Connected to form a primary winding 402. Furthermore, after connecting one end of the electric wire to the terminal 411 of the bobbin 409, the electric wire is wound once around the bobbin 409 so as to be substantially parallel to the primary winding 402, and the other end of the electric wire is connected to the terminal 412 to make a primary winding. 403.
[0007]
FIG. 4 is a diagram showing a method of forming a primary winding described in Utility Model Registration Publication No. 2530618. After one end of the electric wire is connected to the terminal 421, the electric wire is wound once around the bobbin 409, the electric wire is connected to the terminal 422 to form the primary winding 402, and then the electric wire is once wound around the bobbin 409 and connected to the terminal 423. Thus, a primary winding 403 is obtained.
[0008]
FIG. 5 shows a method of forming a primary winding described in Utility Model Registration Publication No. 2530618. A bobbin 409 is provided with a middle flange portion 430 having a terminal at the center of the winding drum portion. After connecting one end of the electric wire to the terminal 431, the electric wire is wound once around the bobbin 409, and the electric wire is connected to the terminal 432 of the middle flange portion 430 to form the primary winding 402. Subsequently, the electric wire is wound once around the bobbin 409 and connected to the terminal 433 to form the primary winding 403.
[0009]
[Problems to be solved by the invention]
When using a switching transformer with a large voltage ratio between the input and output of the power converter, that is, a very high step-up ratio (turning ratio between the primary winding and the secondary winding), compared to the current flowing through the secondary winding of the transformer Therefore, the current flowing through the primary winding becomes extremely large, and it is required that an electric wire having a large cross-sectional area be used as the primary winding in order to reduce the resistance value of the primary winding. However, the transformer itself is preferably small, and has the following problems.
[0010]
For example, if a transformer having the primary windings 402 and 403 each having one turn and the secondary winding 404 having 200 turns is formed by the method shown in FIG. 3, the two primary windings are wound around the bobbin 409 in parallel. In addition, the DC resistances and inductances of these windings are different, and a difference occurs in the magnitude of the magnetic field formed by each primary winding, resulting in a decrease in conversion efficiency. In particular, when the number of turns of the primary winding is small, such as one turn, the characteristic difference between the two primary windings is more remarkable than when the number of turns is large.
[0011]
In addition, if it is created by the method shown in FIG. 4, the characteristic difference between the two primary windings becomes smaller, but the DC resistance and inductance increase as the length of the primary winding becomes longer.
[0012]
In the case of making by the method shown in FIG. 5, first, half (100 turns) of the secondary winding is wound around the winding part 434, and the other half (100 turns) is wound around the winding part 435. The length L of the winding portion of the bobbin 409 becomes longer by at least the thickness t of the middle flange portion 430. Therefore, although the characteristic difference between the two primary windings is small, the DC resistance and inductance are increased by the length of the primary winding (although shorter than the method of FIG. 4).
[0013]
In the method shown in FIG. 5, it is conceivable to reduce the lengths L1 and L2 of the winding portions 434 and 435 by winding the secondary winding around the winding portions 434 and 435 in multiple layers. However, increasing the number of layers increases the size of the transformer, increases the DC resistance of the secondary winding, and lowers the magnetic coupling. Of course, the embodiment shown in FIG. 4 has a problem that the cost of the transformer is increased and the size of the transformer is increased due to the middle flange portion 430 and its terminal.
[0014]
The present invention is to solve the above-described problems individually or collectively, and has an object to improve power conversion efficiency.
[0015]
Another object is to reduce the size and height of the power converter.
[0016]
[Means for Solving the Problems]
The present invention has the following configuration as one means for achieving the above object.
[0017]
The transformer according to the present invention is a transformer having a very high step-up ratio, which is used for a power conversion device, and a secondary winding wound substantially evenly around a winding body of a winding core, and both ends of the winding body. It has two primary windings wound in the vicinity, respectively, and a plurality of terminals arranged on both outer sides of the winding drum section, and the two primary windings are electrically connected to the nearest terminals, respectively. It is characterized by having been done.
[0018]
A power conversion device according to the present invention includes the above-described transformer and a plurality of switching elements constituting a push-pull switching circuit.
[0019]
A power generation device according to the present invention includes the above-described power conversion device and a solar cell.
[0020]
The manufacturing method according to the present invention is a method for manufacturing a transformer having an extremely large step-up ratio, which is used in a power conversion device, wherein a secondary winding is wound substantially evenly around a winding body of a winding core. Two primary windings are wound around each of both ends of the winding body, and the two primary windings are electrically connected to the nearest terminals arranged on both outer sides of the winding drum.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a transformer according to an embodiment of the present invention will be described in detail with reference to the drawings.
[0022]
[Constitution]
FIG. 6 is a diagram illustrating a configuration example of the transformer according to the embodiment, which is characterized in that a primary winding 102 and a primary winding 103 are wound around both ends of a winding core 113, respectively.
[0023]
As shown in FIG. 6, the core 113 refers to a structure around which the primary windings 102 and 103 and the secondary winding are wound, and a magnetic core or a bobbin is typical.
[0024]
When the winding core 113 is a magnetic core, its characteristics are not limited, but since the operating temperature and a desired shape are easily formed, a Mn-Zn-based or Ni-Zn-based ferrite core is preferable. A material having a large saturation magnetic flux density is preferable. In this case, the shape of the magnetic core is preferably a bar (I shape) in consideration of the winding of the electric wire, and the cross-sectional shape thereof can be appropriately selected such as a corner, an ellipse, and a circle. Further, as shown in FIG. 7, it is preferable that a U-shaped (C-shaped) core 915 is butted against both ends of the I-core 914 to form a closed magnetic circuit, and an insulating material such as an insulating tape is sandwiched between the butted surfaces. Thus, a gap can be formed in the magnetic path to adjust the inductance of the winding.
[0025]
When the winding core 113 is a bobbin, a structure as shown in FIG. 8 is preferable, and flange portions 1017 and 1018 for preventing the wound electric wire from dropping off from the winding drum portion 1016 are provided at both ends of the winding drum portion 1016. Is preferred. Further, outside the flanges 1017 and 1018, there are pedestals 1019 and 1020 integrally formed with the winding drum 1016, and the pedestals 1019 and 1020 are provided with a plurality of terminals 1021 and 1022. preferable. Instead of the pin terminals as shown in FIG. 8, a surface mounting terminal that can be surface mounted on a printed circuit board may be used. However, it is preferable that each of the plurality of terminals 1021 and 1022 is disposed in a line-symmetrical positional relationship with respect to the winding direction of the electric wire.
[0026]
Further, as shown in FIG. 9, the bobbin may have a structure having a separator 1123 that divides the winding drum 1016. In that case, the secondary winding is also split into two windings. The primary winding may be wound over the secondary winding or wound under the secondary winding (between the secondary winding and the winding drum 1016). The latter is more preferable for the purpose of lowering the direct current resistance.
[0027]
Further, as shown in FIG. 10, the bobbin may have a structure having a separator 1226 for dividing the winding drum 1016 into three parts. In that case, a secondary winding is wound between the two separators, and two primary windings are wound between each separator 1226 and the flange 1017 (or 1018). The separator may be provided on a part of the outer periphery of the winding drum 1016 as shown in FIG. 10 or may be provided over the entire circumference of the winding drum 1016 as shown in FIG.
[0028]
In the case where a plurality of terminals are provided, it is preferable that the terminal to which the primary winding is connected and the terminal to which the secondary winding is connected be arranged at the farthest position. Further, as shown in FIG. 11, a gap 1327 is provided in the pedestals 1019 and 1020 to separate the terminal for the primary winding from the terminal for the secondary winding, so that the insulation distance between the primary and the secondary is sufficiently secured. Is preferred. Further, when the transformer is mounted on a printed circuit board, the insulation distance can be obtained by piercing the substrate between the terminal for the primary winding and the terminal for the secondary winding.
[0029]
When the winding core 113 is a bobbin having a winding drum 1016, a hole for inserting a magnetic core is provided inside the winding drum 1016, and a magnetic path is formed by inserting the magnetic core into this hole. The shape of the hole is determined according to the cross-sectional shape of the magnetic core to be inserted, such as a square, an ellipse, or a circle.
[0030]
As shown in FIG. 12, the magnetic core includes a main magnetic leg 1428 inserted into the insertion hole 1431 of the bobbin, a side magnetic leg 1429 disposed around the bobbin, and a connection between the main magnetic leg 1428 and the side magnetic leg 1429. A shape having a bridging portion 1430 is preferable. For example, shapes such as EE type, EI type, EER type, and EIR type described in JIS C 2514 “E type ferrite core”, or PP type described in JIS C 2516 “pot type ferrite core”, Shapes such as RM type and EP type can be used. In addition, shapes such as a ferrite core manufactured by TDK Corporation, an EEM type, an LP type, a PQ type, and an EPC type can also be used as appropriate.
[0031]
● Electric wire
The electric wire used in the present embodiment is not particularly limited, but may be an electric wire having heat resistance, flexibility, oil resistance, solderability, insulation durability, and the like that match the use conditions and production conditions of the transformer. Specifically, Class 1 and Class 2 oil-based enameled copper wires, Class 0, Class 1 and Class 2 formal copper wires, Class 0 and Class 1 formal aluminum wires, and Formal flat angle described in JIS C 3202 "Enameled wire" Copper wire, Class 1, Class 1 and Class 2 polyester copper wire, Class 1, Class 2 and Class 3 polyurethane copper wire, Class 0, Class 1 and Class 2 fusible polyurethane copper wire, and Class 0, Class 1 and Class 2 Two types of polyesterimide copper wires can be used.
[0032]
Since the primary winding needs to have a low loss when a high current is applied, a shape having a larger cross-sectional area is preferable, and a rectangular wire having high space efficiency can be suitably used.
[0033]
When the switching frequency is high, it is also preferable to reduce the loss due to the skin effect by using a so-called litz wire in which a plurality of the above-mentioned wires are combined as the primary winding.
[0034]
Further, a multi-parallel enameled wire obtained by integrating a plurality of the above-mentioned wires in parallel can also be used.
[0035]
In addition, if a wire having three layers of insulating coating is used, the arrangement of the insulating material between the primary winding and the secondary winding can be omitted, thereby reducing the number of transformer manufacturing steps and reducing the size of the transformer. it can.
[0036]
In the transformer of the present embodiment, the effect is greater when the number of turns of the primary winding is smaller, and the maximum effect is obtained when the primary winding has one turn.
[0037]
【Example】
Hereinafter, various embodiments will be described.
[0038]
Embodiment 1
FIG. 13 is a diagram for explaining the transformer according to the first embodiment. The primary winding has one turn and the secondary winding has 175 turns, and has a circuit configuration shown in FIG. Hereinafter, a specific method of creating the transformer will be described step by step.
[0039]
Using BDK-17-318D of TDK Corporation as a bobbin, as shown in FIG. 14, one end of an electric wire is tied to the terminal 104d and soldered. Then, after winding the electric wire around the winding drum 113 in a multilayered manner 175 times, the other end of the electric wire is entangled with the terminal 105d and soldered to form the secondary winding 107. In addition, one kind of polyurethane electric wire (1UEW) and a diameter of 0.2 mm are used for the secondary winding.
[0040]
Next, a polyester adhesive tape No. 5 manufactured by Nitto Denko Corporation with a base material of 55 μm and an adhesive of 25 μm. 31C is wound around the secondary winding 107 to form an insulating layer between the primary and the secondary.
[0041]
Next, one end of a litz wire (maximum finished outer diameter 0.679 mm) obtained by bundling 20 kinds of polyurethane wires (1 UEW) having a diameter of 0.1 mm is entangled with the terminal 104a and soldered. Then, after the litz wire is wound once around the winding drum section 113, the other end of the litz wire is tied to the terminal 104b and soldered to form the primary winding 102. Similarly, one end of the same type of litz wire is entangled with the terminal 105a and soldered. After winding the litz wire once around the winding body 113 in the same direction as the primary winding 102, the other end of the litz wire is tied to the terminal 105 b and soldered to form the primary winding 103.
[0042]
Further, as Comparative Example 1, a transformer was prepared by using the same type of electric wire by the method shown in FIG. FIG. 25 is a diagram illustrating the transformer of Comparative Example 1. In each of Example 1 and Comparative Example 1, PC40EP17-Z manufactured by TDK Corporation was inserted into the magnetic core from the insertion holes at both end surfaces of the bobbin. The magnetic core was fixed by 31C to complete the transformer.
[0043]
Ten transformers were prepared as the transformers of Example 1 and Comparative Example 1, respectively. The resistance value of each primary winding was measured by a low resistance meter (HIOKI 3220 HiTESTER), and each primary winding was measured by an LCR meter (HIOKI 3520 LCR HiTESTER). Was measured at 1 kHz. Note that only one set of magnetic cores was used for the measurement in consideration of the characteristic variation of the magnetic cores.
[0044]
15 and 16 show the measurement results. The difference in resistance between the two primary windings (average 0.45 mΩ) of the transformer of Comparative Example 1 is about 9% of the average resistance (4.60 mΩ and 5.05 mΩ) of the two primary windings. . On the other hand, in the transformer of the first embodiment, the difference in resistance between the two primary windings (average 0.01 mΩ) is about 0.2 of the average resistance between the two primary windings (4.57 mΩ). % And very small.
[0045]
Considering that there is almost no difference in inductance between the two primary windings in the transformers of Example 1 and Comparative Example 1, the transformer of Example 1 has a DC resistance between the two primary windings. It can be said that the difference was significantly reduced.
[0046]
Subsequently, the above-described transformer was incorporated in a power converter 202 having a circuit configuration shown in FIG. 17, a solar cell 209 and a load 210 were connected to the power converter 202, and power conversion efficiency was measured.
[0047]
FIG. 18 is a view showing a pattern of a printed circuit board 231 for mounting a transformer. The transformer is mounted from the back side of the figure. The printed circuit board 231 has lands and patterns for mounting the components constituting the power conversion device 202 shown in FIG. 17, but lands and patterns other than those necessary for mounting the transformer are omitted in FIG. Then, the terminals of the transformer are inserted into the holes of the printed circuit board 231, and the transformer is mounted on the printed circuit board 231 by soldering.
[0048]
The holes into which the terminals 104a and 105b are inserted are connected by a pattern 238, and a center tap on the primary side of the transformer 201 shown in FIG. 17 is formed. Also, patterns 234 and 235 connected to switching elements 203 and 204 shown in FIG. 17 are connected to holes into which terminals 105a and 104b are inserted. Further, the patterns 237 and 236 connected to the holes into which the terminals 104d and 105d are inserted are connected to the terminals of the rectifier (diode bridge) 205 shown in FIG.
[0049]
It is preferable that the two patterns 234 and 235 connecting the primary winding and the switching element have the same impedance.
[0050]
Next, an outline of the operation of the power converter 202 shown in FIG. 17 will be described.
[0051]
DC power input from the solar cell 209 to the input terminal of the power converter 202 is smoothed by the capacitor 207 and supplied to the switching elements 203 and 204 such as MOS FETs via the transformer 201. Then, DC power is converted to AC power by alternately turning on / off switching elements 203 and 204.
[0052]
The AC power input to the transformer 201 is boosted according to the transformation ratio of the transformer 201 (1: 175 in the present embodiment), rectified by the rectifier 205 and converted into DC power. Further, the DC power is supplied to the load 210 after being smoothed by the capacitor 206. Note that, depending on the specifications of the pulsating current and the noise of the DC power supplied to the load 210, a filter inductor may be provided between the rectifier 205 and the capacitor 206, or both the inductor and the capacitor 206 may be omitted. is there.
[0053]
Further, although only two switching elements are shown in FIG. 17, actually, FS100UMJ manufactured by Mitsubishi Electric was used in four parallels. In this case, when 5 V is applied to the gate of the switching element, the resistance value between the drain and the source of the switching element decreases to about 0.7 mΩ. Therefore, the resistance value of the primary winding of the transformer 201 greatly affects the conversion efficiency of the power conversion device 202.
[0054]
The control circuit 208 shown in FIG. 17 includes a control power supply unit 209, a reference wave generation unit 210, and a driver 211. When the input voltage of the power conversion device 202 reaches a voltage at which the control power supply unit 209 starts, power is supplied from the control power supply unit 209 to the reference wave generation unit 210 and the driver 211. The reference wave generation unit 210 generates a reference rectangular wave having a preset frequency and supplies the reference rectangular wave to the driver 211. The driver 211 generates gate drive signals S1 and S2 for alternately turning on / off the switching elements 203 and 204 based on the reference rectangular wave, and supplies the gate drive signals S1 and S2 to the gates of the switching elements 203 and 204.
[0055]
FIG. 19 is a diagram illustrating a solar power generation device in which a power conversion device 202 built in a housing is attached to a solar cell 209. The solar cell 209 was operated with an optimal operating voltage of 1 V and an optimal operating current of 10 A at an irradiation intensity of 1 sun using a solar simulator. Then, the power conversion efficiency η when the transformers of Example 1 and Comparative Example 1 were mounted on the power converter 202 was measured. Note that the power conversion efficiency η is represented by the following equation.
η = output power of power converter / input power of power converter × 100%
[0056]
FIG. 20 is a diagram showing the measurement results of the power conversion efficiency. FIG. 20 shows that the power conversion efficiency using the transformer of Example 1 is on average slightly less than one point as compared with the case of using the transformer of Comparative Example 1.
[0057]
As described above, according to the transformer of the first embodiment, the difference in the DC resistance between the two primary windings is reduced, and the power conversion efficiency of the power converter can be improved.
[0058]
Embodiment 2
Hereinafter, the transformer according to the second embodiment will be described. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.
[0059]
FIGS. 21 and 22 are diagrams illustrating the transformer according to the second embodiment. The number of turns, bobbins, and magnetic cores of the primary and secondary windings are the same as in the first embodiment. The type and configuration of the electric wire of the secondary winding 107 and the method of insulating the primary and secondary are the same as in the first embodiment.
[0060]
The primary winding of the second embodiment is different from the first embodiment in that a litz wire (maximum finish outer diameter: 1.032 mm) in which 37 types of polyurethane wires (1 UEW) of 0.1 mm in diameter are bundled is used. One end of the litz wire is entangled with the terminal 104a and soldered and wound once around the winding drum portion. At this time, the litz wire is unwound and wound around a half area of the winding drum portion. Then, the other end of the litz wire is entangled with the terminal 104b and soldered to form the primary winding 102.
[0061]
Here, the polyester adhesive tape No. 31C is wound around the winding drum once. Then, one end of the same litz wire as the primary winding 102 is entangled with the terminal 105a and soldered, wound once around the winding body in the same direction as the primary winding 102, and then connected to the other end of the litz wire. The primary winding 103 is tied to the terminal 105b and soldered. The resistance value of the primary winding 102 was 3.62 mΩ, and the resistance value of the primary winding 103 was 3.57 mΩ. Thus, the resistance value of the primary winding could be reduced as compared with the first embodiment.
[0062]
The transformer of Example 2 was assembled into the power converter 202 in the same manner as in Example 1, and the power conversion efficiency η was measured under the same conditions as in Example 1 by combining with the solar cell 209. As a result, 90.3% was obtained. As a result, the power conversion efficiency was improved by one point as compared with the transformer of Example 1.
[0063]
In this way, the litz wire having the same cross-sectional area of each wire but having a large number of strands is widely wound around the winding body as the primary windings 102 and 103, so that the resistance value of the primary winding is larger than that of the transformer of the first embodiment. And power conversion efficiency can be improved. Furthermore, by winding the wire by unwinding the litz wire, not only can the resistance value be reduced, but also the height (size) of the winding portion can be reduced. The size can be reduced.
[0064]
Embodiment 3
Hereinafter, the transformer according to the third embodiment will be described. In the third embodiment, the same reference numerals are given to configurations substantially similar to those of the first or second embodiment, and detailed description thereof will be omitted.
[0065]
FIG. 23 and FIG. 24 are diagrams illustrating the transformer according to the third embodiment. The number of turns of the primary and secondary windings and the magnetic core are the same as in the first embodiment.
[0066]
In the third embodiment, a bobbin having the separator 1226 shown in FIG. 10 is used. First, a litz wire obtained by bundling 20 types of polyurethane wires (1 UEW) having a diameter of 0.1 mm is entangled with the terminal 104a and soldered. Then, after winding the litz wire once around the winding drum section, the other end of the litz wire is tied to the terminal 104b and soldered to form the primary winding 102. Similarly, one end of the same type of litz wire is entangled with the terminal 105a and soldered. After winding the litz wire once around the winding body in the same direction as the primary winding 102, the other end of the litz wire is tied to the terminal 105 b and soldered to form the primary winding 103.
[0067]
Next, one end of the electric wire is entangled with the terminal 104d and soldered. Then, after winding the electric wire around the winding drum part in a multilayer (or single layer) 175 times in an aligned manner, the other end of the electric wire is entangled with the terminal 105d and soldered to form the secondary winding 107. In addition, one kind of polyurethane electric wire (1UEW) and a diameter of 0.2 mm are used for the secondary winding. In addition, in the part where the primary winding and the secondary winding near the terminal intersect, insulation is achieved by covering the secondary winding with an insulating tube. The resistance of the primary winding 102 was 3.61 mΩ, and the resistance of the primary winding 103 was 3.60 mΩ.
[0068]
Then, a magnetic core made of PC40 manufactured by TDK Corporation and processed to match the shape and size of the bobbin of Example 3 was inserted into the insertion holes on both sides of the bobbin. The magnetic core was fixed by 31C to complete the transformer.
[0069]
In the transformer of the third embodiment prepared in this way, the primary windings 102 and 103 can be wound directly around the bobbin body, so that the primary windings 102 and 103 are placed on the secondary winding 107 and the insulating layer. The lengths of the primary windings 102 and 103 are shorter than those of the first and second embodiments, in which the resistance value can be reduced. Therefore, when the transformer of the third embodiment is incorporated in the power converter 202 and its power conversion efficiency η is measured, 90.4% is obtained, which is 1.1 points higher than the transformer of the first embodiment, The power conversion efficiency was improved by 0.1 point compared to.
[0070]
In the transformer of the third embodiment, similarly to the transformer of the second embodiment, not only the resistance value can be reduced, but also the height (size) of the winding portion can be reduced, so that the transformer can be downsized. The size of the power converter can be reduced.
[0071]
【The invention's effect】
As described above, according to the present invention, power conversion efficiency can be improved.
[0072]
Further, the power conversion device can be reduced in size and height.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a switching transformer of a power converter in which a main circuit of the power converter has a general push-pull type switching circuit;
FIG. 2 is a diagram showing a configuration of a switching transformer of a power converter in which a main circuit of the power converter has a general push-pull type switching circuit;
FIG. 3 is a diagram showing a state of a primary winding of the transformer shown in FIGS. 1 and 2;
FIG. 4 is a diagram showing a method of forming a primary winding described in a utility model registration publication;
FIG. 5 is a diagram showing a method of forming a primary winding described in a utility model registration publication;
FIG. 6 is a diagram illustrating a configuration example of a transformer according to the embodiment;
FIG. 7 is a view showing an example of the shape of a magnetic core;
FIG. 8 is a view showing an example of the shape of a bobbin;
FIG. 9 is a diagram showing an example of the shape of a bobbin.
FIG. 10 is a view showing an example of the shape of a bobbin;
FIG. 11 is a view showing an example of the shape of a bobbin;
FIG. 12 is a view showing an example of the shape of a magnetic core;
FIG. 13 is a diagram illustrating a transformer according to the first embodiment.
FIG. 14 is a diagram illustrating a transformer according to the first embodiment.
FIG. 15 is a diagram showing measurement results of inductances of Example 1 and Comparative Example 1.
FIG. 16 is a view showing measurement results of resistance values of Example 1 and Comparative Example 1.
FIG. 17 is a diagram showing a circuit configuration of a power conversion device used for measuring power conversion efficiency.
FIG. 18 is a view showing a pattern of a printed circuit board for mounting a transformer;
FIG. 19 illustrates a photovoltaic power generation device.
FIG. 20 is a diagram showing measurement results of power conversion efficiency.
FIG. 21 is a diagram illustrating a transformer according to the second embodiment.
FIG. 22 is a diagram illustrating a transformer according to the second embodiment.
FIG. 23 is a diagram illustrating a transformer according to the third embodiment.
FIG. 24 is a diagram illustrating a transformer according to a third embodiment;
FIG. 25 is a diagram illustrating a transformer of Comparative Example 1.

Claims (18)

A transformer having a very large boost ratio used in a power converter,
A secondary winding wound almost evenly around the winding drum of the core,
Two primary windings respectively wound near both ends of the winding drum portion,
Having a plurality of terminals arranged on both outer sides of the winding drum portion,
The two primary windings are each electrically connected to the nearest terminal. The transformer according to claim 1, wherein the core is a bar-shaped magnetic core. 3. The magnetic recording medium according to claim 2, further comprising a pair of U-shaped magnetic cores magnetically coupled to each of both longitudinal end surfaces of the rod-shaped magnetic core to form a magnetic path. Trance. The transformer according to claim 1, wherein the winding core is a bobbin having the cylindrical winding body. 5. The bobbin according to claim 4, wherein the bobbin has pedestal portions on both outer sides of the winding drum portion, and the plurality of terminals are arranged on the pedestal portion substantially in parallel with a winding direction. Trance. The transformer according to claim 5, wherein the plurality of terminals are a plurality of pin terminals embedded in the pedestal portion. The air gap is provided in the pedestal portion between a terminal to which the primary winding is electrically connected and a terminal to which the secondary winding is electrically connected. Transformer described in. The transformer according to claim 4, wherein the bobbin has flanges at both ends of the bobbin. The bobbin has two separators that divide the winding drum portion, the primary winding is wound between one of the separators and the flange portion, and the secondary winding is provided between the two separators. The transformer according to claim 8, wherein is wound. The transformer according to claim 4, wherein a hole for inserting a magnetic core is provided inside the winding drum portion. The magnetic core includes a main magnetic leg inserted into the hole, a side magnetic leg disposed outside the bobbin, and a bridging portion that magnetically couples the main magnetic leg and the side magnetic legs. The transformer according to claim 10, wherein the transformer has: The transformer according to claim 1, wherein an electric wire obtained by bundling a plurality of insulated electric wires is used as the primary or secondary winding. The transformer according to claim 1, wherein the primary winding is wound around an electric wire obtained by bundling a plurality of insulated electric wires. The transformer according to claim 1, wherein a rectangular electric wire is used as the primary or secondary winding. A power converter comprising a transformer according to any one of claims 1 to 14, and a plurality of switching elements forming a push-pull switching circuit. The power converter according to claim 15, wherein each of the plurality of switching elements includes a plurality of switching elements connected in parallel. A power generator comprising the power converter according to claim 15 or 16 and a solar cell. A method for manufacturing a transformer having a very large boost ratio, which is used for a power conversion device,
The secondary winding is wound almost evenly around the winding core of the core,
Winding two primary windings around each end of the winding drum,
The manufacturing method according to claim 1, wherein the two primary windings are electrically connected to nearest terminals arranged on both outer sides of the winding drum portion, respectively.

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