JPH0945534A - Reactor core with excellent superposed-wave characteristic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a reactor core whose iron loss is extremely low when it is used under a waveform condition under which harmonics are superposed. SOLUTION: In a reactor core using a high-silicon steel plate which contains 4 to 7wt.% of Si, the high-silicon steel plate which satisfies a relationship of (Ωp, n)/(ΣWs, n)<1.15 where the fundamental-wave iron loss is designated Wp, 1 and the n-th harmonic wave loss is designated Ws, n, when the high silicon steel plate is excited by a waveform containing harmonic components, an iron loss for the fundamental-wave at a time is designated Ws, 1 and an iron loss for the n-th harmonic is designated Ws, n when the silicon steel plate is excited by a single sine wave.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reactor core excited by a waveform in which a plurality of waveforms are superimposed.

[0002]

2. Description of the Related Art Conventionally, as the capacity of a switching device has been increased, the capacity of a power supply incorporating an inverter power supply has also been increased, and it has been adopted in various power supply equipment fields. The waveform of the switching circuit of these inverter power supplies is a waveform in which a fundamental wave of a relatively low frequency and a high frequency component are superposed, and these days, the switching frequency of this inverter has become higher, and along with this, The wave components are becoming higher in frequency. Therefore, the temperature rise of the reactor iron core used around the inverter power supply, that is, the iron loss of the iron core has become a problem.

Conventionally, such a temperature rise of the reactor,
That is, in order to solve the problem of increasing high-frequency iron loss, the same measures as those for normal high-frequency measures have been taken, such as using a thin steel plate as the iron core material or using a material with high specific resistance.

[0004]

However, conventionally,
Materials with low high-frequency iron loss are used as materials for the reactor core that is used in excitation waveforms in which harmonics are superimposed.However, depending on the waveform conditions, even though materials with low high-frequency iron loss are used, the reactor There has been a problem that the iron loss may become abnormally large and the temperature of the reactor iron core may rise. The present invention has been made to solve such a problem, and an object of the present invention is to provide a reactor iron core having extremely low iron loss even when used in a waveform condition in which harmonics are superimposed. .

[0005]

A reactor core having excellent superimposed wave characteristics according to an aspect of the present invention has a Si content of 4 to 7 wt%.
In a reactor iron core using a high silicon steel sheet containing a fundamental wave core loss when excited by a waveform containing a harmonic component,
When p, 1, the nth harmonic loss is Wp, n, the iron loss at the fundamental frequency when excited by a sine wave alone is Ws, 1, and the iron loss at the nth harmonic is Ws, n, A high silicon steel plate that satisfies the following formula is used. (ΣWp, n) / (ΣWs, n) <1.15

A reactor core having excellent superposed wave characteristics according to another aspect of the present invention has a minimum bending radius of steel plate of 5.
A high silicon steel plate having a workability of 0 mm or less is used.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In this embodiment, even though a material having a low high-frequency iron loss is used, the iron loss is increased in a waveform in which harmonics are superimposed, and research is repeated. As a result, the iron loss of the reactor can be made extremely low by using a material in which the ratio of the iron loss under the excitation condition where multiple waveforms are superimposed to the iron loss under the single sine wave excitation condition is specified within a specific range. It was found that it is possible.

Next, this embodiment will be described in detail. Usually, a harmonic superimposed waveform such as a PWM wave used in an inverter power supply contains a high frequency component, so that the reactor iron core must be a material having a low high frequency iron loss. In the case of a silicon steel sheet, the higher the Si content, the higher the specific resistance, so that the high frequency iron loss can be reduced, but the Si content exceeding 7% is mechanically very brittle and not practical. Further, if the Si amount is less than 4%, the high frequency iron loss is very large.

Therefore, in applications where the upper limit of the temperature rise of the reactor is strict, it is necessary to specify the Si amount to 4 to 7%, and more preferably, the Si amount 6 which is particularly excellent in iron loss characteristics and noise characteristics. It is to be 0.0 to 7.0%.

In the present embodiment, as described above, S
In addition to defining the i amount, the fundamental iron loss when excited by a waveform containing harmonic components is Wp, 1, and the nth harmonic loss is Wp, n
, Ws, 1 is the iron loss at the fundamental wave frequency when the sine wave is excited alone, and Ws, n is the iron loss at the nth harmonic, and Ws, n is the iron loss when the sine wave is solely excited. The ratio to the iron loss Wp, n when excited by the superposed wave is set to satisfy the following equation.

(ΣWp, n) / (ΣWs, n) <1.15

Now, the reason for defining such a relationship will be described. FIG. 1 shows the characteristic of the iron loss value of the iron core when the reactor is actually excited by the PWM waveform with respect to the ratio of the iron loss when the sine wave is excited alone and the iron loss when the superimposed wave is excited. It is a characteristic diagram. As shown in FIG. 1, it can be understood that the actual reactor iron loss can be suppressed to be extremely low in the range where the superimposed wave iron loss ratio is 1.15 or less.

Further, in this embodiment, the relationship between the superposed wave iron loss ratio and the steel plate material was studied, and it was found that the superposed wave iron loss ratio can be reduced by improving the workability of the steel plate. FIG. 2 is a characteristic diagram showing the characteristics of the superimposed wave iron loss ratio with respect to the minimum bending radius of the steel plate. As shown in FIG. 2, it can be understood that the superimposed wave core loss ratio can be set to 1.15 or less by setting the minimum bending radius of the steel plate to 5.0 mm or less. Furthermore, the minimum bending radius of the steel sheet is preferably 2.0 mm or less, which is excellent in the characteristics of the superimposed wave iron loss ratio.

In this embodiment, the superposed wave iron loss ratio is set to 1.15 or less by improving the workability of the steel plate, but the superposed wave iron loss ratio is set to 1.15 by another method.
It may be set as follows, that is, (ΣWp, n) / (ΣWs,
Any high silicon steel plate may be used as long as it satisfies the formula of n) <1.15.

[0015]

EXAMPLE Here, a silicon steel sheet (sheet thickness: 0.1 mm) having a Si content of substantially 6.5% is prepared, and iron loss (W1 at a frequency of 10 kHz and a magnetic flux density of 0.1 T as high frequency magnetic characteristics of the steel sheet is prepared). /Ten
K) is shown in Table 1.

[0016]

[Table 1]

The W1 / 10K of the steel sheets prepared this time are all around 10 W / kg, as shown in Table 1, and although there is no difference in high frequency iron loss, they are processed in the order of A → B → C → D → E. It is a steel plate that shows a high value. Table 1 shows the minimum bending radius as an example of the workability index. It is considered that this difference in workability is caused by the difference in the amount of oxygen at the grain boundaries due to the difference in atmospheric conditions during the production of the steel sheet.

Then, the steel plate shown in Table 1 is wound on the iron core CS2.
After processing to 5, strain relief annealing of 800 ℃ × 2 hours,
The varnish was soaked and dried, and then cut, and a spacer having a thickness of 0.1 mm was put in two places to produce a cut core. Then, the produced cut core was wound with a winding number of 22 and magnetic characteristics were measured.

First, the fundamental wave is 50 Hz and the magnetic flux density is 0.5.
A superposed waveform of 5T, superposed wave 16kHz, and magnetic flux density of 0.024T, and iron loss when excited at each frequency were measured. Table 1 shows the ratio of the measured results as the superimposed iron loss ratio.
Shown in Thus, although the high frequency iron loss W1 / 10K was the same, the superimposed wave iron loss ratio showed a value of 1.19 to 1.06 depending on the workability. It is considered that this is because the material having better workability has less microcracks in the bending R portion due to processing, and the low magnetic field characteristics are higher.

The relationship between the minimum bending radius of the steel plate and the superposed wave iron ratio is as shown in FIG. 2. By setting the minimum bending radius of the steel plate to 5.0 mm or less, the superposed wave iron loss ratio is 1.15. It turns out that you can:

Next, for each of the steel plates shown in Table 1, the PW actually used for the inverter power supply output
The reactor iron loss was measured with an M waveform at a load factor of 6.5%. FIG. 3 is a characteristic diagram showing the characteristics of reactor core loss with respect to the type of steel sheet. As shown in FIG. 3, C,
It can be seen that in the steel sheets D and E, the reactor iron loss is extremely low.

For each of the steel sheets shown in Table 1, the relationship between the superimposed iron loss ratio and the reactor iron loss is as shown in FIG. 1, and when the superimposed iron loss ratio is 1.15 or less, the reactor iron loss value is extremely low. It was confirmed to be low.

[0023]

As described above, according to the present invention, the fundamental wave iron loss when excited by a waveform containing a harmonic component is Wp,
If the iron loss at the fundamental frequency is Ws, 1 and the iron loss at the nth harmonic is Ws, n, then (ΣWp , n) / (ΣWs, n) <
Since a high silicon steel plate that satisfies the relationship of 1.15 is used and a high silicon steel plate having a minimum bending radius of 5.0 mm or less and excellent workability is used, the waveform condition in which harmonics are superposed is used. It also has an effect that the iron loss becomes extremely low when used in.

[Brief description of drawings]

FIG. 1 shows that the reactor is actually PW with respect to the ratio of the iron loss when excited by a sine wave alone and the iron loss when excited by a superposed wave.
It is a characteristic view showing the characteristic of the iron loss value of the iron core when it is excited by the M waveform.

FIG. 2 is a characteristic diagram showing characteristics of a superposed wave iron loss ratio with respect to a minimum bending radius of a steel plate.

FIG. 3 is a characteristic diagram showing characteristics of reactor core loss with respect to steel sheet types.

Claims (2)

[Claims] 1. A reactor iron core using a high silicon steel sheet containing 4 to 7 wt% of Si, wherein the fundamental iron loss is Wp, 1 and the nth harmonic loss is Wp, when excited by a waveform containing a harmonic component. n, the iron loss at the fundamental wave frequency when excited by a sine wave alone is Ws, 1, and the iron loss at the nth harmonic is Ws, n, use a high silicon steel sheet that satisfies the following formula Reactor core with excellent superposed wave characteristics. (ΣWp, n) / (ΣWs, n) <1.15 2. A reactor iron core having excellent superposed wave characteristics according to claim 1, wherein a high silicon steel plate having a minimum bending radius of 5.0 mm or less and having excellent workability is used.