JP2736134B2 - DC reactor iron core - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to an iron core of a DC reactor used for reducing a harmonic component of a DC circuit of a rectifier.

(Conventional technology) As an uninterruptible power supply for a computer, a CVCF power supply for obtaining a constant voltage and a constant frequency output is widely used.

In this CVCF power supply, there is a rectifier in which a DC reactor is inserted for the purpose of reducing harmonic components of the DC circuit.

Generally, in a magnetic circuit of a DC reactor, the magnetic flux density B _DC of the _{DC component} is expressed by the following equation.

B _DC = 0.4πNI _DC / Lg Here, NI _DC is a DC ampere-turn, Lg is the total gap length, and the case where the sectional area of the gap is equal to the apparent sectional area of the iron core. As can be seen from the above equation, the gap length Lg is provided so as not to saturate the magnetic circuit even when a large current flows.

If the air gap on the magnetic circuit is intensively increased in one place, the leakage magnetic flux and the coupling coefficient with the windings are deteriorated. For this reason, the DC reactor has a configuration in which a gap is provided at the upper and lower ends of the leg iron core magnetic path or the leg iron core magnetic path is divided into a plurality of parts and each divided part is provided with a gap. In this case, a spacing plate made of an insulating material is interposed in the gap.

FIG. 2 shows a dry DC reactor having such an iron core configuration, and FIG. 3 shows an iron core.

Here, 1 is a resin-molded coil, and 2 is an iron core penetrating the coil and constituting a magnetic circuit. The iron core 2 is fixed with a plurality of iron core tightening bolts 5 via an upper contact plate 3 and a lower leg plate 4. Also, as shown in FIG. 3, the iron core 2 has leg iron magnetic paths 202a and 202b formed by alternately stacking block-shaped leg irons made of laminated silicon steel plates via insulating spacers 203. Leg core magnetic path 202
The magnetic circuit is composed of yoke iron core magnetic paths 201a and 201b arranged above and below so as to close both ends of the a and 202b.

(Problems to be Solved by the Invention) In the magnetic circuit, a high-frequency component enters for the purpose of lowering a high-frequency component, which is a function of an original DC reactor, and a high-frequency ripple on a DC component excites an iron core. Causes magnetostrictive vibration. Magnetostrictive vibration is leg iron core and spacing plate 20
Either a relative vibration is generated between them, or a vertical vibration is transmitted to the yoke iron core, and further transmitted to the mounting floor of the DC reactor.
In any case, an unpleasant vibration sound is generated only by the high frequency component, which has a problem.

Accordingly, it is an object of the present invention to provide a DC reactor iron core in which vibration and vibration noise due to magnetostriction of the iron core are extremely reduced.

[Constitution of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a leg core magnetic path having a leg core formed by laminating silicon steel plates, and a silicon steel plate laminated. In the iron core of a DC reactor comprising a yoke iron core magnetic path closing the leg iron core, a 6.5% silicon steel plate is used at least partially for the leg iron core.

(Operation) The direct generation source of the vibration sound is the leg iron core magnetic path. At least a part of the leg iron core constituting the leg iron core magnetic path is made of an iron core material having almost no magnetostriction. As a result, the vibration noise, which is a problem of the DC reactor, is drastically reduced.

Example An example of the present invention will be described below.

FIG. 1 is a view of a leg core 202 constituting a leg core magnetic path. The configuration of the leg iron core 202 is such that silicon steel plates 202-1 are laminated, end plate contact plates 202-2 are arranged on both sides thereof, and integrated with fastening bolts 202-3. Most of the leg core 202 is formed by laminating directional silicon steel sheets, and a predetermined lamination thickness 1 is formed by using 6.5% silicon steel sheets on both sides in the laminating direction. As shown in the table below, this 6.5% silicon steel sheet has lower magnetostriction and iron loss (1 kHz) than ordinary oriented silicon steel sheet.

In the leg core 202 shown in FIG. 1, the magnetic flux flows in the direction A perpendicular to the upper surface of the leg core 202. Therefore, magnetostriction is usually large in the vertical direction.
Since it is a 6.5% silicon steel sheet, the magnetostriction is extremely small. In this case, the same applies to the case where 6.5% silicon steel sheet is used for not only a part but also all of the leg cores. Leg iron core 202
If the magnetostriction is greatly reduced, no relative vibration occurs between the spacer and the spacing plate, and no vibration noise is generated. Therefore, the vibration does not propagate from the leg core magnetic path to the yoke core magnetic path or outside the leg core magnetic path.

Here, the reason for not using a 6.5% silicon steel plate for the yoke core magnetic path is that the yoke core magnetic path also generates magnetostriction, but the direction of the magnetostriction is the longitudinal direction, which affects other parts and generates vibration noise. This is because it does not act to greatly propagate the vibration.

Another reason is that it is not necessary to use an expensive and difficult-to-work 6.5% silicon steel sheet even for a yoke core magnetic path with little effect.

[Effects of the Invention] As described above, by using 6.5% silicon steel sheet for at least a part of only the leg iron core formed by stacking silicon steel sheets, generation of annoying vibration sound peculiar to the conventional DC reactor can be achieved. The width of vibration transmission to the outside can be made extremely small.

[Brief description of the drawings]

FIG. 1 is a perspective view of a leg core of a DC reactor according to one embodiment of the present invention, FIG. 2 is a front view showing a structure of a general dry DC reactor, and FIG. 3 is a front view showing an iron core of the DC reactor. is there. 1 ... resin molded coil, 2 ... iron core, 3 ... upper plate, 4 ... leg plate, 5 ... tightening bolt, A ... direction of magnetic flux, l ... leg core width, 201 ... yoke core , 201a, 201b ... Upper and lower yoke cores, 202 ... Leg cores, 202a, 202b ... Right leg cores, 202-1 ... Oriented silicon steel plate, 202-2 ... End plate, 202-3 ... … Tightening bolt, 203 …… Space plate.

Claims (1)

(57) [Claims] 1. A DC reactor core comprising: a leg core magnetic path having a leg core formed by laminating silicon steel sheets; and a yoke core magnetic path formed by laminating silicon steel sheets and closing the leg core. An iron core of a DC reactor, wherein at least a part of the leg iron core is made of a 6.5% silicon steel sheet.