JP2729848B2 - AC reactor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an AC reactor mainly used for an electronic device circuit such as an industrial robot.

(Related Art) Conventionally, many reactors used for a power supply unit of a commercial frequency use a silicon steel plate as an iron core material due to its characteristics. Such a reactor is attached to power supply circuits in various fields and functions to suppress inrush current. There are two types of silicon steel sheets: directional and non-directional. Generally, the directionality has a higher magnetic permeability and a larger inductance value.

The core made of silicon steel sheet is called a wound core made by winding a band-shaped plate around a core, and 0.35mm ~
It is roughly divided into two types, called sheet cores, which are punched out of a sheet of about 0.5 mm thickness into a sheet by pressing, but from the viewpoint of workability and cost, those using the latter sheet core have become mainstream. ing.

The iron core made of this silicon steel sheet shows stable inductance characteristics at a commercial frequency, but it can be said that ferrite having a lower resistivity is more suitable for use in a high frequency band. That is, ferrite is a polycrystalline sintered body in which several kinds of compounds are compounded, and has a feature that eddy current is hardly generated and can be used at a higher frequency than other metallic magnetic materials. Taking advantage of this feature, it has a great effect on removing high-frequency noise and surge pulses generated from a high-power motor or the like (those whose return current flows through the ground are called common mode noise).

This is called common mode noise. A copper wire is wound around the ferrite core of a closed magnetic circuit in the same phase, so that the differential mode current (line current at the commercial frequency) flowing in each coil is canceled out by the iron core. It has a structure to prevent saturation.

Actually, two coils (three coils for three-phase) are not completely balanced and wound, so it is difficult to cancel out all magnetic flux, but unbalance at a level that does not saturate the iron core If it is a current, a large inductance can be obtained for a common mode current.

(Problems to be Solved by the Invention) However, the conventional reactors do not particularly have a function as a common mode coil, and the use of the common mode coil is very effective for removing the common mode noise. The common mode coil has a problem that when used in a device with a large current, the winding diameter becomes large and the coil itself becomes considerably large, so that use in a place where space is limited is troublesome.

The present invention has been proposed in view of the above, and its purpose is to combine the functions of both a reactor and a common mode coil, and to have a stable inductance characteristic with respect to the fluctuation of the differential mode current, To provide an AC reactor that has a large inductance with respect to common mode current, has the same level of noise removal performance as a common mode coil, and is lightweight and compact despite having such performance. is there.

(Means for Solving the Problems) That is, in the present invention, an EI type sheet core 1 is used for a differential mode, three EI type sheet cores 1 are combined in a lateral direction, and these sheet cores 1 are joined. The EE-type ferrite cores 5 of long legs for common mode are provided to face each other with a gap therebetween on the sides thereof, and the common coil 7 is wound only on the center legs thereof to achieve the above object. Have achieved.

(Operation) In the present invention, two magnetic paths are formed in the same coil with the above-described configuration, and a stable inductance characteristic is obtained by a sheet core made of a silicon steel plate against fluctuations in the differential mode current. In addition, a large inductance is obtained by a ferrite core for the common mode current, a normal reactor is provided with a noise removing function, and both the reactor and the common mode coil are combined by a single component.

In addition, the weight and size are reduced by sharing the wound coil.

(Embodiment) Figs. 1 to 4 (a) and (b) show an embodiment of the present invention. In this embodiment, a three-phase AC reactor will be described as an example.

First, FIG. 1 shows a sheet core (1) made of a silicon steel sheet used in the present invention. Since a stable inductance can be obtained with respect to a differential mode current, this sheet core (1) is used.

In this sheet core (1), an E-shaped core (2) and an I-shaped core (3) are made into a block, and a gap material (4) such as insulating paper is inserted into a joint surface to adjust the inductance value. .

In the case of three-phase, as shown in FIG.
The above-mentioned three sheet cores (1) are combined in the lateral direction, but each E-shaped core (2)
The length of the leg is shortened. In addition, as shown in FIG.
However, unlike the common mode coil, the adjustment is performed for each coil (7) because each coil (7) must have an independent inductance with respect to the differential mode current.

FIG. 3 shows a ferrite core (3) formed by joining two long-legged E-shaped ferrite cores (5a) to a sheet core (3) combined with three in order to have a function as a common mode coil. 5 shows a state in which step 5) is combined.

In this case, dimensions A, B, V, U, W, and X of each part of the combined and integrated three sheet cores (1) and the ferrite core (5) provided on the side thereof are the same. Is set.

Ferrite core (5) and sheet core (1)
A gap is formed with the insulating paper (6) therebetween. This gap is for preventing the magnetic flux from wrapping around, and the EI type core (2) of the sheet core (1),
(3) It is thicker than the gap formed between them.

The E-shaped ferrite core (5a) faces the butted portion so that no gap is generated. This is because the unbalance current increases due to the gap, and there is a risk that the ferrite core (5) may saturate.
This is because the inductance is also reduced, and in order to prevent this, it is necessary to bring the pair of E-shaped ferrite cores (5a) into close contact with each other.

FIGS. 4 (a) and 4 (b) show a state in which a common coil (7) is wound around each central leg in the same phase to form an AC reactor having the function of a common mode coil. In this case, the ferrite core (5) incorporated in the sheet core (1)
Since three coils (7) are wound in the same phase with respect to the magnetic path, the magnetic flux due to the differential mode current cancels each other and acts only on the common mode current (noise current) to function as a common mode coil. It has become.

(Effects of the Invention) As described above, according to the present invention, since a ferrite core is provided on a sheet core made of a silicon steel plate with a gap interposed therebetween, both the function as a reactor and the function as a common mode coil are provided, and the differential mode is provided. For the current, a stable inductance characteristic is obtained by the sheet core, and for the common mode current, there is an effect that the common mode noise can be removed by the large inductance of the ferrite core.

In addition, by integrating and integrating the coil of the common mode coil unit with the reactor unit, a lightweight and compact AC reactor can be realized.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a unit sheet core used in the present invention, FIG. 2 is a perspective view of the sheet core in a three-phase state, and FIG. 3 is a core portion including the sheet core of the present invention and a ferrite core. FIG. 4 (a) is a perspective view of an AC reactor of the present invention, and FIG. 4 (b) is a front view. DESCRIPTION OF SYMBOLS 1 ... Sheet core 2 ... E-shaped core 3 ... I-shaped core 4 ... Gap material 5a ... E-shaped ferrite core 5 ... Ferrite core 6 ... Insulating paper 7 ... Coil

Claims (1)

(57) [Claims] 1. An EI-type sheet core (1) is used for a differential mode, three EI-type sheet cores (1) are combined in a lateral direction, and the sheet cores (1) are laterally joined to each other. An AC reactor comprising a common mode long leg EE-type ferrite core (5) facing each other through a gap, and a common coil (7) wound around only a central leg thereof.