JPS6031230Y2 - Transformer with leakage inductance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transformer with leakage inductance.

FIG. 1 shows an electric wire to which a winding bobbin is applied, such as a large capacity high frequency switching power supply.

In the failure cause, AC is an alternating current power supply, RF is a rectifier that rectifies the alternating current power supply AC, and C1 is a capacitor that smoothes the output of the rectifier RF.The alternating current power supply AC1 rectifier RF and capacitor C1 constitute the direct current power supply of the high frequency switching power supply. There is.

Ql and Q2 are switching transistors, and both transistors Q1 and Q2 are connected in a push-pull manner.

T is a high frequency transformer, in which two identical primary windings Na and Nb are formed, and both primary windings Na.

One end of Nb is connected to the ten terminal of the DC power supply, and the other ends of both primary windings Na and Nb are connected to one end of the DC power supply via switching transistors Ql and Q2, respectively.

DI, D2 are rectifier diodes connected to both ends of the secondary winding N2 of the high frequency transformer T, L is a smoothing reactor, D3. D4 is an overvoltage suppression diode, C2 and C3 are overvoltage suppression capacitors, and Qc is a control device that controls the switching transistors Ql and Q2, which turns on and off the switching transistors Ql and Q2 and converts the DC power into high frequency. It outputs high frequency.

By the way, in the conventional high-frequency transformer used in this high-frequency switching power supply, the coupling between the primary winding N1 and the secondary winding N2 is made as close as possible to rapidly transmit the current on the primary side to the secondary side and to prevent leakage. The main focus was on reducing the inductance and the energy stored in this leakage inductance.

However, the primary winding N1 and the secondary winding N of the high frequency transformer T
There is also a limit to the bond with 2, which is several μH.

For this reason, in order to suppress the overvoltage that occurs during switching, it is necessary to increase the capacitance of the capacitor and also to increase the capacity of the transistor.

Therefore, in recent years, the two primary windings Na and N of the primary winding N1 of a high frequency transformer used in a high frequency switching power supply are
It has been proposed to adopt a high-frequency transformer having a leakage inductance that tightly couples the windings b and loosely couples the primary winding and the secondary winding, contrary to the conventional method.

This slows down the rise and fall of high-frequency switching due to leakage inductance, and suppresses overvoltage applied to switching elements such as transistors.

As this type of high frequency transformer, one shown in FIG. 2 has been proposed.

So, in the cause of defeat, 1 is the two cut cores la, l
2 is a first insulating bobbin inserted into the leg iron of the iron core; 3 is a primary winding wound on the first bobbin; 4 is a cylindrical insulating bobbin 2nd bobbin, 5 is 1
an insulating material inserted between the next winding 3 and the second bobbin 4;
6 is a secondary winding wound on the second bobbin 4;
The primary winding 3 and the secondary winding 6 are loosely coupled.

However, in this transformer, due to variations in the diameter of the second bobbin 4, the shape of the first bobbin 2, and the thickness of the insulating material 5,
A gap was created between the insulating material 5 and the second bobbin, and it was not possible to securely fix the insulating material 5 and the second bobbin.

Furthermore, an insulating material was required to insulate the ends of the primary winding from the iron core.

In addition, when a large number of primary windings are wound, cooling of the outer primary winding is good, but cooling of the inner winding is not sufficient, causing variations in the temperature rise of the windings, and also thick windings. It was necessary to study.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and the primary winding and the iron core are insulated, and both ends of the first bobbin 2 are connected to the second bobbin 4. In addition to providing a gap piece to fix the second bobbin, a space is provided between the secondary windings to improve the cooling effect of the primary winding, and a transformer with leakage inductance that suppresses the temperature rise of the primary winding. Provide utensils.

Next, the present invention will be explained based on an illustrated embodiment.

Figure 2 shows the bobbin on which the primary winding is wound, bobbin 2
A flange-shaped gap piece 7 is provided at both ends.

This gap piece 7 is selected to have a length that allows it to engage with the cylindrical second bobbin 4, as shown in FIG.

Reference numeral 8 in FIG. 4 is an insulating flat plate that provides a gap between the primary windings to be wound in layers, and notches 9 are provided at both ends of the flat plate 8. As shown in FIG. 9 is configured to engage the gap piece 7 of the first bobbin 2 .

When manufacturing a transformer using this first bobbin 2 and flat plate 8, first, as shown in FIGS. 6 and 7, a part 3a of the primary winding 3 is wound around the first bobbin 2. Then, place the flat plate 8 on top of this primary winding and place the notch 9 of the flat plate 8.
is engaged with the gap piece 7 of the first bobbin 2.

The remaining part 3b of the primary winding 3 is wound on this flat plate 8.

Since the flat plate 8 of the remaining part 3b of the primary winding 3 protrudes outward from the part 3a of the primary winding 3,
A gap is created between a part 3a of the primary winding 3 which is wound outward from the part 3b of the primary winding 3 and the remaining part 3b.

Further, the secondary winding 6 is wound around the second bobbin 4.

Then, the first bobbin 2 with the primary winding 3 wound thereon is inserted into the second bobbin 4 and engaged.

It is produced by inserting the cut cores la and lb into the winding constructed in this manner and fixing the cut cores 1a and 1b.

Note that in the above embodiment, only the gap piece of the first bobbin is inserted into the second bobbin, but a groove is provided inside the second bobbin, and the gap piece of the first bobbin is inserted into this groove. They may be engaged.

Alternatively, the width of the gap piece of the first bobbin may be made small and the width of the cutout portion of the flat plate may be made the width of the iron core, and the flat plate may be engaged with the iron core.

In the transformer having the leakage inductance of the present invention configured as described above, the second bobbin is securely fixed to the first bobbin, and a flat plate is placed between the overlapping primary windings. Since a gap is provided between the primary windings by the projections 10 on the opposing flat plates, the primary windings are cooled.

Further, when the flat plate is engaged with the first bobbin, a part of the primary winding can be temporarily fixed, so that winding of the remaining part of the primary winding becomes easy.

Further, the first bobbin has the advantage that sufficient insulation between both ends of the primary winding and the iron core can be obtained.

[Brief explanation of drawings]

Figure 1 is a circuit diagram of a large capacity high frequency switching power supply.
Fig. 2 is an explanatory diagram of the external appearance of a known high frequency transformer, Fig. 3 is a perspective view of a bobbin, Fig. 4 is an explanatory diagram of a flat plate, Fig. 5 is an explanatory diagram of a combination of a bobbin and a flat plate, and Fig. 6 is an explanatory diagram of a combination of a bobbin and a flat plate. FIG. 7 is an explanatory view of the combination of the bobbin, flat plate, and primary winding. 1...Iron core, LA, LB...Cut core, 2...First bobbin, 3...Primary winding, 4.Curve/No. 2 bobbin, 5... insulation material,
6... Secondary winding wound on the second bobbin,
7... Gap piece, 8... Flat plate, 9...
...Notch, 10...Protrusion.

Claims (1)

[Scope of utility model registration request] Winding the secondary winding on a cylindrical bobbin and overlapping it 1
In a transformer having a leakage inductance with a gap between a primary winding and a secondary winding, the bobbin around which the primary winding is wound has a collar-like shape at both ends, and the cylindrical shape A transformer having a gap piece that engages with the inside of a bobbin, and a leakage inductance provided between primary windings wound by overlapping flat plates having notches that engage with the gap piece.