JPS60185179A - Magnetomotive force detector - Google Patents

Abstract

PURPOSE:To enable the well detection of magnetomotive force by mounting a negative feedback system by using a magnetic modulation type magnetic flux detector formed of core, exciting coil and detection coil, by using the detection coil as magnetomotive force negative feedback coil and detecting a magnetomotive force signal component of which the frequency band is limited. CONSTITUTION:Reflux magnetic flux generated in a core 1 corresponding to input magnetomotive force Fs receives amplitude modulation corresponding to an AC exciting current Iext to exciting coil 2 and voltage with predetermined frequency proportional to magnetomotive force Fs is generated in output coil 3 in such a form that said exciting current is differentiated and detected through the corresponding BPF. The coil 3 is connected to a feedback loop 7 and magnetomotive is subjected to negative feedback and, without separately providing magnetomotive magnetomotive force feedback coil or a terminal necessary for said coil, tolerant input is enlarged on the basis of feedback control by a usual type magnetic modulation type magnetic flux magnetomotive force by output reduced in strain.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a 7I! system that negatively feeds back to the magnetic flux a quantity that depends on the output signal of a conventional magnetically modulated magnetic flux detector for magnetic field detection. ,
The present invention relates to a magnetomotive force detector comprising an i-magnetic force negative feedback system, and in particular to an improvement to provide a winding type and output signal type equivalent to those of the magnetic modulation type magnetic flux detector described above.

BACKGROUND ART AND PROBLEMS Conventional magnetic modulation type magnetic flux detectors are constructed as shown in FIGS. 1 to 3. Figure 1 is a schematic diagram of a magnetic modulation type magnetic flux detector, in which 1 is the core, 2 is the excitation winding, 3 is the detection winding, Iext is the supply current, ΦS is the return flux, and E5 is the detection winding 3. represents the voltage induced in Figure 2 is an equivalent magnetic circuit diagram of the detector shown in Figure 1, with 4! i modulator, 5 is the detector a3 and the electrical circuit connected after it, FI3
represents human magnetomotive force, and R represents magnetic resistance. 3(a) and 3(b) are charts showing the flow of the detector operation shown in FIG. 1, where Pe is the incremental permeance of the excitation part, 111
is the number of turns of the detection winding, K is a constant, and ω represents the angular frequency of the excitation current. In this system, the return magnetic flux Φ is modulated by the angular frequency ω of the excitation S current I ext, and 2ω is the fundamental wave. This becomes an amplitude modulated wave due to the input magnetomotive force Fs. A voltage Es is generated in the output winding in a differentiated form.

This means that there may or may not be a curved part at Mf61 in Fig. 3(a), and in the conventional magnetic flux detector, Fig. 3(a) (no part surrounded by broken green) Either use E, (2ωt) as the output signal, as shown in Figure 3 (bl), or use a 2ω-component filter F to generate a balanced modulated wave E (2ωt). Alternatively, in the magnetomotive force detection method, as shown in Fig. 3 (
a) As shown in (some parts surrounded by broken lines), Es
(2ωt) was used as the output signal.

The present applicant previously wrote in % Application No. 58-206804,
We improved the conventional magnetic modulation type magnetic flux detector for magnetic field detection and proposed a magnetomotive force detector consisting of a magnetomotive force negative feedback system that negatively feeds back a quantity depending on the output signal to the magnetic flux. Figure 4 is a schematic diagram of the magnetomotive force detector, in which 6 is the magnetomotive force negative feedback winding, and o is the feedback current. FIG. 5 is an equivalent magnetic circuit diagram of the detector shown in FIG. 4, where 7 means a feedback loop and Fo means a feedback magnetomotive force. FIG. 6 shows a conventional configuration example of a magnetomotive force detector using the detector shown in FIG. 4, where n2 is the number of turns of the magnetomotive force negative feedback winding 6, and K2 is a constant. In this configuration, in order to obtain the return magnetomotive force FC corresponding to the human-powered magnetomotive force FsK, the feedback current Ic is set to 8, so that the modulated signal E,
(2ωt)-i: or g; From (zωt), four arithmetic detection,
Amplitude detection is performed by a sample and hold circuit AD, etc., and the output voltage thus obtained is converted to direct current by a V-1 converter, thereby obtaining a direct current proportional to the width value of these signals.

This magnetomotive force detector has the advantage that the permissible input is expanded and output with less distortion is obtained. Winding layer 6. or an alternative terminal was required.For this reason, the type of conventional magnetic flux detector is rigid, and the detection part in the device and the detection part of the above magnetomotive force detector are % koji and output. It was not possible to create compatibility between signal formats.

Object of the Invention The object of the present invention is to provide a magnetomotive force having the same winding and output (M type) as the conventional magnetic modulation type magnetic flux detector, but also having the advantages of the magnetomotive force negative # return thread. The purpose of this invention is to provide a detector.

SUMMARY OF THE INVENTION In order to achieve the second object, a magnetomotive force detector according to the present invention includes a magnetic core in a magnetic circuit, and a magnetic flux detection means that generates an output voltage in response to magnetic flux circulating through the core. , the magnetomotive force is generated according to the difference between the input magnetomotive force and the negative feedback magnetomotive force, and the detection winding receives a negative magnetomotive force. It is also used as a feedback winding, and the magnetomotive force signal component is detected from the output of the winding in a limited frequency band. In an advantageous embodiment of the invention, the signal ratio is increased by generating a signal similar to the negative kttR component in the feedback loop and adding or subtracting it to the winding output signal. In a further advantageous embodiment of the invention, the balanced modulated wave output is generated from the voltage signal applied to the detection winding or from the signal obtained by integrating the voltage, via the radio frequency device. can be obtained.

Hereinafter, the present invention will be explained in more detail using examples with reference to the drawings, but these are merely illustrative and it is understood that various modifications and improvements may be made without going beyond the scope of the present invention. Of course.

Embodiment Fig. 7 is a schematic diagram showing the basic configuration of the magnetomotive force detector of the present invention.The type of winding is exactly the same as Fig. 1, and the detection winding 3 is used for negative magnetomotive force return. The four differ in that they are also used as glands. That is, in the present invention, the detection winding deals with voltage output, and the magnetomotive force negative feedback winding deals with current, and attention is paid to the fact that voltage and current are handled separately. The equivalent magnetic circuit diagram of the device shown in FIG. 7 is expressed as Iij+ as shown in FIG.

In this system, the @ wire has resistance, so this results in R
When current flows, unnecessary voltage increases by 1 tatami to the output voltage. Since a large difference cannot be obtained between this voltage and the output voltage, the S/N ratio of the output signal of the detection winding as a magnetic flux signal is very poor as it is.

By the way, it is known that the voltage EIS induced in the detection winding with respect to the human magnetomotive force Fs K and the signal E obtained from the voltage EIS through the bandpass filter 2 are strip width modulated waves having a main component of 2ω. Furthermore, from the signal detection conditions, 2ω is set to be sufficiently large compared to the band of the normal input magnetomotive force F8. This shows that there is also a difference in the A-type imperial region between the return force Fc and 2ω. Therefore, as mentioned earlier, the signal proportional to the input magnetomotive force F0 and the voltage E2 induced in the detection winding are output in the form of 1 tatami, but there is a difference in the band between these signals, and this The voltage Ej induced in the detection winding in the superimposed signal is included on the high frequency side.

FIG. 9 shows an embodiment of the present invention using the detector shown in FIG. 7, in which feedback is generated by passing the signal E8 induced in the detection winding 3 through a low-pass cut filter HPF as shown in the figure. Magnetic force F. It is possible to reduce the band components of -Ji and extract the Es component from the -Ji output voltage. Set VI-I
Return current l from the converter. is the negative feedback magnetomotive force F given to the detection winding 3. occurs. This band-separating force equation constitutes a magnetomotive force detector of the conventional magnetic modulation type magnetic flux detector shown in FIG. 1, which is a reel type with negative feedback applied.

Depending on the conditions, the feedback magnetomotive force F. If it is not possible to provide a large difference between the band of 2ω and the band of 2ω, or the negative feedback magnetomotive force F. The amplitude of the voltage E induced in the detection winding
s may be too thick. In such cases, there are some difficulties, such as requiring a low-pass cut filter HPF with steep characteristics.

On the other hand, the voltage component caused by the feedback current 10 that produces the feedback magnetomotive force Fc included in the output voltage shown in FIG. 7 is proportional to 1-c. Therefore, the voltage that would be generated by the resistor of the winding is created in advance, and the detection winding 3
By subtracting it from the output voltage of
It is shown in figure O. In the figure, VB is a variable resistor that produces the voltage that would be generated by the resistor of the winding and subtracts it from the output voltage of the detection winding 30.
Rcoil is a return electric crab. Voltage E in the winding detected by
This schematically shows that o is visited.

In FIG. 3 [bl, a balanced modulated wave is created through a bandpass filter F. On the other hand, in Fig. 9, it is 1, and the output is @ryu'Kameryu■. There's a lot of yelling. Therefore, there is no compatibility between these outputs.

However, the signal E5, which is the signal at the stage before the bandpass filter F in FIG. 3, is also included in the signal in FIG. 9. Furthermore, 11ii@ of those signals is proportional to the DC output lc. Since IC and Fs are proportional, Et
Or Es and F8 are also proportional. Therefore, if the gain distribution within the signal system is adjusted appropriately and the E8 or FJ8 signal is output through the bandpass filter F), the same balance will be achieved in the magnetomotive force detector as in the magnetic modulation type magnetic flux detector. Modulated wave output can be obtained.

An embodiment of the present invention using such a 114 structure is shown in FIG.

Also, since the main signal component of F is included in the 2ω imperial region, 2
The ω imperial filter F can also be included in the negative feedback system.

This configuration is shown in FIG. In this configuration, since the bandpass filter F is inserted in series with the low-pass cut filter HPFK, there is an advantage that the low-pass reduction effect is large within the feedback loop.

As shown in Figure 12, by appropriately distributing the gain and obtaining the output signal via a bandpass filter, magnetic modulation type magnetic flux detection is possible without adding a separate external modulator to direct current. A balanced modulated wave output equivalent to that of the magnetomotive force detector can be obtained from the magnetomotive force detector.

As described in detail, according to the present invention, the same @linear type as the conventional magnetic modulation type magnetic flux detector can be used even in a magnetomotive force detector having a magnetomotive force negative feedback system, and bandpass filtering By adding a detector, the output signal type can be the same as the conventional one, and a wide range of compatibility can be obtained between the conventional magnetic modulation type magnetic flux detector and the magnetomotive force detector.

[Brief explanation of drawings]

Figures 1 and 4 are schematic diagrams of a magnetically modulated magnetic flux detector and a conventional magnetomotive force detector, respectively, and Figures 2i and 5 are equivalents of the detectors shown in Figures 1 and 4, respectively. Fig. 3 (al, bJ and Fig. 6 are block diagrams showing a conventional magnetomotive force detector using the detectors shown in Fig. 1 and Fig. 4, respectively, and Fig. 7 is a block diagram of the conventional magnetomotive force detector using the detector shown in Fig. A schematic diagram showing the basic configuration of the magnetomotive force detector of the invention, FIG.
An equivalent magnetic circuit diagram of the detector shown in the figure, FIG. 9 is a block diagram showing an embodiment of the present invention using the detector shown in FIG.
The silk diagrams to the nest diagrams 12 are block diagrams showing other embodiments of the present invention corresponding to three different embodiments of the stripe diagrams. 1-°・Core, 2... Excitation winding, 3... Detection winding,
4... Modulator, 5... Detection winding and electric circuit connected thereto, 6... Winding for negative feedback of firing force, 7...
・Feedback loop.

Claims (4)

[Claims] (1) A magnetic flux detection winding that includes a magnetic core in a magnetic circuit and generates an output voltage in response to magnetic flux flowing back into the core;
magnetomotive force negative feedback means for generating a negative feedback magnetomotive force by applying a current corresponding to the output voltage to the detection winding, and the above-mentioned magnetomotive force is generated according to the difference between the human-powered magnetomotive force and the negative feedback magnetomotive force. A magnetomotive force detector characterized in that it is configured to. (2) The magnetomotive force detector according to claim 1, wherein the magnetomotive force signal component is detected by limiting the frequency band from the output of the winding. (3) 4 similar to the negative feedback component in the negative feedback means;
Claim 1, characterized in that the signal ratio is reduced by generating No. 6 and adding or subtracting it to the winding output signal.
Magnetomotive force detector described in section. (4) The negative feedback means includes a bandpass filter and obtains a balanced modulated wave output from the voltage signal induced in the detection winding or a signal obtained by integrating the voltage through the bandpass filter. A magnetomotive force detector according to claim 1.