JPH03181108A - Interference wave suppression transformer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a device for interrupting interference waves superimposed on a power supply line and intruding into load equipment, and particularly for preventing high frequency noise that causes malfunction of electronic equipment. , relates to a disturbance wave prevention transformer suitable for preventing disturbances due to input voltage fluctuations.

[Conventional technology] In recent years, malfunctions of various electronic devices due to interference waves, etc., and the resulting system failures have developed into a major social problem. Malfunctions of load equipment due to light/heavy loads and fluctuations in the power supply voltage of commercial bus lines are important problems that cannot be ignored.

In conventional interference wave prevention transformers, input coils and output coils are not arranged in the same manner as in general transformers, but are arranged alternately or in parallel as described in Japanese Utility Model Publication No. 17882/1982. A gap M is provided between the coils to increase leakage reactance between input and output, reduce stray capacity as much as possible, and provide high impedance to high frequency components, including high frequency components that enter the input coil. The structure is such that harmful interference waves are not induced to the output side. In addition, since the frequency is high, the input and output coils are each covered with a conductive plate made of copper or aluminum to prevent leakage magnetic flux that uses the air core as the magnetic path instead of the iron core as the magnetic path from interlinking with the output coil. It is alms.

[Problems to be Solved by the Invention] The above-mentioned conventional technology blocks leakage magnetic flux that does not use the inside of the iron core as a magnetic path by applying electromagnetic shielding to each of the input and output coils, among magnetic flux caused by high-frequency components that have entered the input coil. However, the high-frequency magnetic flux flowing inside the core is consumed as iron loss by using materials with low effective high-frequency magnetic permeability, but even if the core has low effective high-frequency magnetic permeability,
It is impossible to consume all high frequency components other than the fundamental frequency as iron loss, and conventional interference wave prevention transformers have no effect on suppressing input voltage fluctuations. There is a problem in that the worst case scenario is that this directly manifests itself as a fluctuation in the output voltage, causing the device's stop function to activate, resulting in a system failure.

The present invention has been made in order to solve the above problems, and is an interference wave prevention transformer that has functions to prevent interference caused by high frequency waves entering the input coil and to stabilize the output voltage against fluctuations in the input voltage. is intended to provide.

[Means for Solving the Problem] The above object is to provide a transformer in which an input coil and an output coil are wound separately, a magnetic shunt provided to prevent the propagation of high frequencies, and a magnetic shunt provided to the output coil. This is achieved by means of an anti-interference transformer with a connected resonant capacitor. That is, a magnetic shunt equipped with an amorphous electromagnetic steel plate is provided between the input coil and the output coil, or at least one of the input coil and the output coil, and a resonant capacitor connected to the output coil. This constitutes an interference wave prevention transformer.

[Function] The magnetic flux generated in the iron core due to the high frequency component of the interference wave that has entered the input coil is consumed as iron loss by using a material with low effective high frequency permeability. The current is returned to the magnetic shunt made of crystalline magnetic steel sheets, and no high frequency components are induced in the output coil. In addition, this magnetic shunt acts like a series reactor for the fundamental wave component, and the current flowing through this series reactor is the vector sum of the iron resonance between the capacitor connected to the output side and the main magnetic path on the output side. , depending on the input voltage variation,
The current becomes a leading current or a lagging current, and the voltage across the series reactor increases or decreases, thereby stabilizing the output voltage against input terminal fluctuations.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure is a perspective view of an embodiment of the present invention, in which 1 is an input coil and 2 is an output coil, each of which is independently and alternately arranged on the center leg 5 of the center core type iron core 3. Then, a magnetic shunt 4 formed by laminating amorphous electromagnetic steel sheets shown in FIG. Fit into place. Furthermore, a resonant capacitor 9 is connected in parallel to the output coil.

Here, the main core 3 is made of a material with low effective magnetic permeability at high frequencies, and the magnetic shunt 4 made of an amorphous electromagnetic steel sheet is configured to have a small cross-sectional area with respect to the main core 3.

The function of removing interference waves and stabilizing the output voltage against input voltage fluctuations in the present invention will be explained below with reference to FIGS. 3, 6, and 7. FIG. 3 is a vertical cross-sectional view of FIG. 1, and shows that interference waves containing high frequency components in addition to the fundamental frequency superimposedly enter the input coil l through the power supply line, but the main iron core 3 Iron cores with low effective magnetic permeability at high frequencies, e.g. T-
By using 120 grade non-oriented silicon steel plate, the effective magnetic flux due to the high frequency component of the interference wave is consumed as iron loss in the main iron core 3, and no high frequency component is induced in the output coil 2. Also, input coil 1 and output coil 2
are arranged independently and separately, and a barrier shield (electrostatic shield) 8 made of copper or aluminum is inserted to increase the leakage reactance between both coils, reduce stray capacity, and suppress high frequency components. Although consideration has been given to high impedance in all cases, the above-mentioned configuration is well-known as an interference wave prevention RONI transformer.

In the 31st mesh, the cross-sectional area of the main core 3 is sufficiently large compared to the cross-sectional area of the magnetic shunt 4, so the impedance is low, and the magnetic flux induced by the fundamental frequency component does not flow into the magnetic shunt 4 side. Only the main iron core 3 is bent L'↓, and an electromotive force of fundamental frequency 'A is generated in the output coil 2. On the other hand, the magnetic flux due to the high frequency is not entirely consumed by iron loss, and depending on the frequency band, r=flows through the iron core 3 and tends to link with the output coil. At this time, the magnetic shunt 4 has a high-frequency effective magnetic permeability higher than that of the L iron core 3 and has a low impedance to high-frequency components, so the magnetic flux due to the high-frequency component flows into the magnetic shunt 4 and has a high-frequency effective magnetic permeability. Since the current does not flow through the main core 3, which has low magnetic permeability, and does not interlink with the output coil 2, no electromotive force is induced by interference waves. That is, the magnetic shunt 4 functions as a bypass magnetic path for high frequency components.

Next, the function of stabilizing the output voltage against input voltage fluctuations will be explained.

FIG. 6 shows an equivalent circuit of the interference wave prevention transformer according to the present invention when the turns ratio of the fundamental wave is 1:1. FIG. 7 is a graph showing the relationship between voltage and current at each part in FIG. 6. In FIG. 6, 14 indicates a reactance formed between the input and output by the magnetic shunt 4, 15 indicates a saturation reactor due to the output side inductance, and 13 indicates a capacitance due to the resonance capacitor 9. In the relationship between voltage and current in FIG. 7, ■ is the output voltage V, and ■ is the relationship between the current flowing through the saturation reactor]5, and ■ is the output voltage V. The relationship between the current flowing through the capacitor 13 and the current obtained as the vector sum of the currents flowing through the saturation reactor 15 and the capacitor 13 and the output voltage V.

The relationship ``■'' is the relationship between the current flowing in the series reactor and the voltage across this reactor, ``■=■+■'', which represents the input voltage. Therefore, when looking at the same current, ■ indicates the input voltage, and ■ indicates the output voltage. Here, the point where the input voltage and the output voltage are equal is used as a reference, and when the input voltage decreases, the current flowing through the series reactor 14 advances as shown in FIG. 7, and the voltage at both ends increases. The output voltage will be increased. Conversely, when the input voltage increases, the current flowing through the series reactor 14 becomes a lagging current, and the voltage across the reactor drops, suppressing the output voltage, and the output voltage remains stable even if the input voltage fluctuates. become. In this way, the magnetic shunt 4, which acts as a bypass for the high frequency component, acts as a series reactor for the fundamental wave, and serves to stabilize the output voltage, thus having two functions.

FIG. 8 is an equivalent circuit of a conventional interference wave prevention transformer, and FIG. 9 is a graph showing the relationship between voltage and current.

14' in FIG. 8 is the reactance generated by providing an isolation gap between the input coil and the output coil as in the conventional structure, and FIG. 9 14' shows the voltage drop caused by this reactance. In FIG. 9, ■' indicates the input terminal, ■' indicates the output voltage, and there is a relationship of ■r=,<2r−■'. As is clear from FIG. 9, fluctuations in the input voltage directly appear as fluctuations in the output voltage, and the conventional interference wave prevention transformer is powerless against fluctuations in the input voltage.

An example of the noise removal effect (normal mode noise reduction) of the interference wave prevention transformer according to the embodiment described above is shown in FIG. 10 as a relationship characteristic diagram between frequency and attenuation rate.

Here, the resonance capacitor 9 of the embodiment shown in FIG. 1 has the effect of a bypass capacitor for high frequency components, and in order to confirm the effectiveness of the magnetic shunt 4 made of amorphous electromagnetic steel sheet, the characteristic diagram shown in FIG. In this case, the resonance capacitor was installed manually, and Figure (a) shows the noise removal characteristics when the magnetic shunt 4 is fitted.
FIG. 2B shows the noise removal characteristics of a conventional interference wave prevention transformer without a magnetic shunt fitted therein. The main core used in the test machine was a non-oriented silicon steel plate (T-120 grade), and the relationship between frequency and magnetic permeability is shown in FIG. 11(b). Similarly, the relationship between frequency and magnetic permeability of an amorphous electromagnetic steel sheet used as a material for forming the magnetic shunt is shown in FIG. 4(a).

The magnetic flux density at the fundamental frequency of the main core is approximately 10,000 Gauss to 13,000 Gauss (1,0 Tesla 1,3 Tesla), and the saturation magnetic flux density of the amorphous electrical steel sheet is 15,000 Gauss to 16,000 Gauss. Since it is Gaussian,
The magnetic flux density of the magnetic shunt for the fundamental frequency is approximately 20,000
If it is set to Gauss or higher, the magnetic impedance becomes infinite, and the magnetic flux due to the fundamental frequency is not shunted to the magnetic shunt, but is entirely linked to the output coil, and does not cause a drop in the output voltage.

Therefore, it is desirable to set the magnetic shunt cross-sectional area to less than /2 of the main core cross-sectional area. In this example, the main core cross-sectional area is 28 cnt, and the magnetic shunt cross-sectional area is 2.8 cnt! The data was collected with the setting set to 1/10 of the cross-sectional area of the main core.

By the way, according to the IEEE report, most of the power supply noise is spike noise of 10kHz to 100kHz and 40kHz.
There are reports that it is classified as transient noise between 0Hz and 5000Hz, and according to a report from IBM in the United States, 49% of noise disturbances in computers are due to transient noise.
It is reported that 40% of the noise is caused by spike noise. In addition, in actual noise measurements, it has been confirmed that the contact opening/closing surge of an electromagnetic switch has a frequency component of 5 kHz to several tens of kHz, and the opening/closing surge of a circuit breaker has a frequency component of 1 kHz to 100 kHz. Since a filter can exhibit its effectiveness in a frequency band of 100 kHz or higher, an interference wave prevention transformer that can obtain an attenuation effect even in a region of 100 kHz or lower is effective against power supply noise.

In conventional interference wave prevention transformers, the noise attenuation effect below l0OkHz is greater than that of filters, but according to the present invention, as can be seen from Figure 10, the noise attenuation effect is 1
A large attenuation effect of approximately 10 dB was obtained in the range of 0 kHz to several 100 kHz, and the effect of the bypass magnetic path was achieved.

This means that in the main core, the higher the frequency, the lower the magnetic permeability, and the higher the frequency component is no longer induced in the output coil, but all the frequency components other than the fundamental wave are not consumed as iron loss, but especially Number of frequency ranges k l (z to 1 kHz, which is a problem as a power supply noise disturbance, not only the attenuation effect due to the reduction of electromagnetic coupling but also the frequency where the magnetic permeability does not decrease sufficiently if there is a high frequency bypass magnetic path as in the present invention) Even in the region, the high frequency component flows into the bypass magnetic path and does not interlink with the output coil and does not induce a high frequency component.This is also shown in Fig. 10.
~several 100k) (clearly observed in the range of z).

FIG. 4 is a perspective view showing another embodiment of the present invention, and FIG. 5 is a longitudinal sectional view of FIG. 4, which provides the same effect as the embodiment of FIG. 1.

In this embodiment, the input coil 1 is attached to the opposing sides of the main iron core 3.
A magnetic shunt 10 made of laminated amorphous electromagnetic steel sheets and shaped like a wound core is installed outside the input coil l in the interference wave prevention transformer in which the output coil 2 is placed, and the interference wave that enters from the input side The magnetic flux due to the high frequency component in response to noise flows through the magnetic shunt lO provided on the input side, and the magnetic flux due to the high frequency component does not flow through the main iron core 3, and no high frequency component is induced on the output side.

[Effects of the Invention] As explained above, the present invention has a magnetic shunt formed of an amorphous electromagnetic steel sheet with a large effective magnetic permeability at high frequencies fitted to the conventional interference wave prevention transformer. By bypassing the high-frequency magnetic flux caused by the widely distributed interference waves to this magnetic shunt, the noise blocking effect can be enhanced, and a large attenuation effect can be obtained.

In addition, this magnetic shunt becomes a series reactor in the fundamental wave, and due to the iron resonance phenomenon between the resonant capacitor inserted in the output coil and the reactance due to the output coil,
The current flowing through the series reactor leads or lags depending on the magnitude of the input voltage, and the voltage across the series reactor increases or decreases, providing a function to stabilize the output voltage against fluctuations in the input voltage.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention, FIG. 2 is a perspective view of a magnetic shunt made of laminated amorphous magnetically conductive steel plates, FIG. 3 is a vertical cross-sectional view of FIG. 1, and FIG. 5 is a longitudinal sectional view of FIG. 4, FIG. 6 is an equivalent circuit of the interference wave prevention transformer of the present invention, and FIG. 7 is a perspective view of each part in FIG. 6. Figure 8 is an equivalent circuit diagram of a conventional interference wave prevention transformer. Figure 9 is a characteristic diagram showing the relationship between voltage and current of each part in Figure 8. Figure 10. 11 is a characteristic diagram showing the relationship between frequency and noise suppression rate in the present invention and conventional interference wave prevention transformers, and FIG. FIG. 3 is a characteristic diagram showing the relationship between effective magnetic permeability. ■...Input coil 3...Main core 5...Central leg 7...Electromagnetic shield 9...Resonance capacitor II, II'...Input terminal 12.12'...Output terminal 13... ...Capacitance 2...Output coil 4...Magnetic shunt 6...Side yoke leg 8...Barrier shield 10...Magnetic shunt 14. 14'...Reactor between input and output 5...Output side saturation reactor

Claims (3)

[Claims] 1. An interference wave prevention transformer comprising an input coil and an output coil wound separately, comprising a magnetic shunt provided to prevent the propagation of high frequencies, and a resonant capacitor connected to the output coil. A special feature of the interference wave prevention transformer. 2. The interference wave prevention transformer according to claim 1, wherein the magnetic shunt is made of a laminated amorphous electromagnetic steel plate installed between the input coil and the output coil. 3. 2. The interference wave prevention transformer according to claim 1, wherein the magnetic shunt is made of a laminated amorphous electromagnetic steel plate attached to at least one of the input coil and the output coil.