JPS5948345B2 - magnetic control device - Google Patents

Description

Detailed Description of the Invention The present invention provides a nonlinear inductance element having a magnetic core made of a magnetic material, a first resistor, a second resistor, a third resistor, a capacitor, and an operational amplifier. The magnetic flux level biased by the signal magnetic field applied to the magnetic core is controlled by the duration of the positive half cycle and negative half cycle of the saturation output voltage of the operational amplifier. It is an object of the present invention to provide a magnetic control device that measures an applied signal magnetic field by magnetoelectrically converting it into a difference.

As a conventional technique, first, the amplitude difference modulation method (edited by the Institute of Electrical Engineers of Japan's Magnetic Amplifier Expert Committee, "Magnetic Amplifier for Measurement", p. 81~
84. Denki Shoin).

This is a method in which a point-symmetric nonlinear element is separately excited by a pulse excitation wave, and the pulse height of a modulated wave appearing on the output side is amplitude-difference-modulated by a signal magnetic field. In this method, the absolute values of the integral value of the positive output voltage induced on the output side and the integral value of the negative output voltage are equal, and even if an integrating circuit is added to the output side, the average DC voltage will be zero. becomes. Therefore, in order to obtain the magnetoelectrically converted DC component, a circuit configuration in which a detection circuit is additionally connected to the output side is required, and therefore it is impossible to directly obtain the DC voltage corresponding to the signal magnetic field from the excitation circuit. It was hot. In addition, this type of method includes a current detection method using a bias rectifier type amplifier (Proceedings of the 1971 National Conference of the Institute of Electronics and Communication Engineers, p. 18).
29). This is equipped with a separate square wave excitation circuit to convert the signal magnetic field applied to the magnetic core into a DC voltage, and a part of the excitation circuit is connected in series with two Zener diodes that operate as nonlinear elements. The circuit configuration is such that the detection function is performed by the circuit containing the magnetic core, and the condition for excitation of the magnetic core is external excitation in which the magnetic core is excited by an excitation power supply provided separately from the circuit containing the magnetic core. In addition, special public service No. 39-15499
The current measurement device of No. 1 has a circuit configuration in which a current input winding is newly added to a magnetic multivibrator consisting of a pair of transistors, and a detection function using a nonlinear element is provided at the downstream stage of the magnetic multivibrator circuit. This is implemented by a waveform shaping circuit that is connected separately and independently from the magnetic oscillation circuit, and its output can be converted into a DC voltage by a low-pass filter. However, a high gain operational amplifier that is operated by a small voltage input has a function of operating as a switching element, and the operational amplifier, which is normally used as a linear element, is used as a nonlinear element that performs a detection function. None of the devices has been found to have a circuit configuration, or even a plan for an integrated configuration that simplifies and downsizes the entire circuit of the device. The present invention relates to a device that configures a magnetic oscillation circuit by coupling an operational amplifier that operates nonlinearly to a nonlinear inductance element, and converts the biased magnetic effect that occurs when a signal magnetic field is applied to a DC voltage.

The features of the present invention include an operational amplifier, a magnetic core,
a nonlinear inductance element consisting of a first winding wound around a magnetic core; a first resistor connected in series to one terminal of the nonlinear inductance element; a capacitor connected in parallel between both terminals of the first resistor; a second resistor connected in series to the other terminal of the first resistor; and a third resistor connected in series to the other terminal of the second resistor and the other terminal of the nonlinear inductance element.
a nonlinear inductance element, a parallel connection of the first resistor and the capacitor, a second resistor, and a third resistor to form a circular circuit; a node between the second resistor and the third resistor;
Connect the nodes of the nonlinear inductance element and the parallel connection of the first resistor and capacitor to the two input terminals of the operational amplifier, and connect the second resistor to the parallel connection of the first resistor and the capacitor, or connect the third resistor and the nonlinear A magnetic control device is provided in which a node with an inductance element is connected to an output terminal of an operational amplifier.

A detailed explanation will be given below with reference to an electrical circuit diagram of an embodiment.

FIG. 1 is an electrical circuit diagram of a first embodiment of the magnetic control device of the present invention.

In the drawings, reference numeral 11 is made of a magnetic material for the purpose of concentrating the signal magnetic field Hs and constituting the nonlinear inductance element. The shape of the magnetic core may be arbitrary, and may be an open magnetic path or a closed magnetic path. 12 is
A pair of terminals of the first winding wound around the magnetic core 11 are connected to the first and fourth nodes 1 and 4 and operate as a nonlinear inductance element.

10 is an operational amplifier, the non-inverting input terminal of which is connected to the first node 1
The inverting input terminal is connected to the third node 3, and the output terminal is connected to the second node 2.

The operational amplifier 10 has a high input impedance, and in the present invention operates as a voltage input controlled switching element that outputs two different saturation voltage levels depending on the voltage input signal. 13 is a resistor R13, and a pair of terminals are connected to the second
It is connected to the node 2 and the first node 1, and the saturated output voltage of the operational amplifier 10 is divided at the first node, and the voltage at the first node, that is, between the terminals of the first winding 12 Voltage V1 is applied to the non-inverting terminal as an input signal.

14 is a resistor R14 and a pair of terminals are connected to the second node 2 and the third node 3; FLs15 is a resistor R15 and a pair of terminals are connected to the third node 3 and the fourth node 4; The fourth node is connected to ground G.

The resistor 14 and the resistor 15 are the output voltage of the operational amplifier 10.
is divided at the third node 3, and this divided voltage signal is input to the inverting terminal of the operational amplifier 10 as the reference voltage signal V3. 16 is a capacitor whose pair of terminals are connected to the first node 1 and the second node 2, and functions to stably sustain magnetic oscillation when the slew rate of the operational amplifier 10 is poor. .

Terminals 17, 18, and 19 are connected to the first node 1 and the second node, respectively.
This is a terminal for taking out the voltage at the node 2 and the fourth node 4 from the magnetic oscillation circuit system. The winding having terminals 20 and 21 wound around the magnetic core 11 and the winding having terminals 22 and 23 are used as a second winding for current input when measuring current.
It is a winding wire that can apply a signal magnetic field Hs to the magnetic core 11 by the current flowing through the second winding wire, and may be used in addition depending on the purpose. Na}, 2
The operational amplifier 10 that outputs two different saturation voltage levels outputs positive and negative saturation voltages when driven by two positive and negative power supplies, and outputs zero voltage and saturation voltage when driven by a single power supply. However, in the present invention, it is possible to use any power source, and the present invention is not limited thereto. In the drawings, according to customary practice, the power supply terminals +,
- has been omitted. FIG. 2 is a diagram for explaining each voltage waveform at the first node, the second node, and the third node. Figure 2b shows each voltage waveform when the signal magnetic field Hs is present.

The operation of the device of the present invention described above will be explained as follows in conjunction with the waveform explanatory diagram shown in FIG.

To simplify the explanation, an example will be described in which the operational amplifier 10 is driven by positive and negative power supplies and the absolute values of the positive and negative saturation output voltages Vs are equal. First, a state in which the signal magnetic field Hs is not applied to the magnetic core 11 will be described. Now, suppose that the operational amplifier 10 is positively saturated and the output voltage is ■. is in a state of +Vs, the operational amplifier 10
The positive saturated output voltage Vs is inputted to the inverting terminal of the resistor 14 as a reference voltage signal V3 divided by the resistance ratio of the resistor 14 and the resistor 15. On the other hand, the impedance of the first winding 12, which operates as a nonlinear inductance element, is determined by the fact that the magnetic flux state of the magnetic core 11 is in an unsaturated magnetic flux state and in the positive direction (hereinafter, the current flowing through the nonlinear inductance element when the output voltage of the operational amplifier is positive). The positive direction is the direction in which the magnet is excited by the
This means that V1>V3 is established between the voltage V1 and the voltage V3, and the voltage waveform is the positive saturation of the operational amplifier 10, as shown in the positive half cycle period of FIG. 2a. The condition persists for some time. However, since the magnetic core 11 has nonlinear characteristics, when the magnetic flux level increases and approaches a positive saturation magnetic flux state, the nonlinear inductance element of the first winding 12 becomes a mere first winding without the magnetic core 11. As the impedance of the first winding 12 decreases, the characteristics of the first winding 12 become closer to those of a linear inductance element due to
The voltage V1 at node 1 decreases, and from the state of V1>V3, V
The state shifts to 1=■3, which corresponds to the state indicated by 4 in FIG. 2a. At the moment when V1 becomes V3, the polarity of the input voltage signal V1-V3〉0 that has been applied to the operational amplifier 10 changes from positive to negative V1-V.
3〈0, so the output voltage V of the operational amplifier 10. is saturated and becomes negative -Vs, and at the same time, the sign of the reference voltage signal at the third node is also inverted. This is the portion corresponding to 8 in FIG. 2a. Therefore, the magnetic core 11 is excited in the opposite direction and enters the unsaturated magnetic flux state again. This is the second
This period corresponds to the period shown in Figure a and Figure aO. In this negative excitation period,
The impedance of the first winding 12 becomes large again, and the impedance of the first winding 12 increases again.
The voltage V at the node is deeply biased toward the negative saturated output voltage, and there is a voltage of 1-V between it and the reference voltage signal 3 at the third node.
The relationship 3 x O is established, and the operational amplifier 10 continues to output the negative saturated output voltage -Vs. This state continues until the magnetic core 11 reaches a negative saturation magnetic flux state. Next, when the magnetic flux level gradually decreases and approaches the negative saturation magnetic flux level, the first winding 12
The value of the impedance decreases, and the voltage V at the first node 1 decreases.
1 gradually becomes higher than the deep negative voltage level and approaches the ground voltage (zero level), and at the next moment, between the negative reference voltage signals V3 and V1 at the third node, V1-V3>
0 is established, and the input voltage signal V1-V3 of the operational amplifier 10
changes from negative to positive voltage (part 9 in Figure 2a), and the operational amplifier 10 again enters the positive excitation period in which it outputs the positive saturated output voltage +Vs, and thereafter repeats this operation. The magnetic oscillation continues. In this case, terminals 18, 19
The voltage waveform observed between v and v is shown in Figure 2a. waveform, and its average DC voltage value V. becomes zero since there is no external magnetic field. Next, a case will be described in which the signal magnetic field Hs exists and is applied in the positive excitation direction of the magnetic core 11, causing the magnetic core 11 to be biased.

Now, the operational amplifier 10 is positively saturated and the output voltage is V.

If it is the moment when becomes +Vs, the signal magnetic field Hs(〉0)
The sum Hs+Hd of the excitation magnetic field Hd (>0) generated by the positive current flowing through the first winding 12 becomes the positive excitation magnetic field of the magnetic core 11, so the positive magnetic field Hs becomes positive faster than when the signal magnetic field Hs is not present. magnetic flux saturation is reached. Therefore, as shown in the positive half cycle period of FIG. 2b, the operational amplifier 1
The period during which 0 remains in a positive saturation state becomes shorter. On the other hand, the period during which the operational amplifier 10 maintains a negative saturation state is the sum Hs+ of the signal magnetic field Hs (>0) and the magnetic field -Hd generated by the negative current flowing through the first winding. (-Hd) becomes a negative direction excitation magnetic field, so the strength of the excitation magnetic field is weaker than when the signal magnetic field Hs does not exist, and as a result,
Negative flux saturation is reached late. Therefore, as shown in FIG. 2b, the duration of the negative excitation half cycle, ie, the duration of the negative saturation of operational amplifier 10, becomes longer. Thus, the output V of operational amplifier 10 at terminals 18,19. The difference between the positive and negative saturation durations of the average DC voltage V. It can be seen that is controlled by the signal magnetic field Hs. Figure 3 shows
In the electrical circuit of the second embodiment of the present invention, the first embodiment of FIG.
This is an example of a modified circuit in which the connections between each terminal of the operational amplifier 10 and the node in the electrical circuit diagram of the embodiment are replaced.

A pair of terminals of the first winding 12 are connected to the first node 12 and a second node 22, a pair of terminals of the resistor 14 are connected to the second node 22 and the third node 3', A pair of terminals of the resistor 15 are connected to the third node 32 and the fourth node 45, and the fourth node 42 is connected to the ground G. resistance 1
The pair of terminals of No. 3 are connected to the fourth node 42 and the first node 12, and the capacitor 16 is connected to the fourth node 42 and the first node 12. The non-inverting terminal of the operational amplifier 10 is connected to the third node 3', the inverting terminal is connected to the first node 12,
The output terminals are respectively connected to the second node 22. The magnetic oscillation operation of this embodiment can be explained from the same standpoint as the first embodiment, but the third node 32 inputs the reference voltage signal to the non-inverting terminal of the operational amplifier 10, and operates as a nonlinear inductance element. The difference is that the terminal voltage change of the operating first winding 12 is inputted to the inverting terminal of the operational amplifier 10 from the first node 1'. FIG. 4 shows the first node 12,
These are diagrams for explaining each voltage waveform at the second node 22 and the third node 32. FIG. 4a shows each voltage waveform when no signal magnetic field Hs exists, and FIG. Each voltage waveform is shown when .

The operation of the second embodiment of the device of the present invention shown in FIG. 3 will be explained in conjunction with the waveform explanatory diagram shown in FIG.
It is as follows.

To simplify the explanation, an example will be described in which the operational amplifier 10 is driven by positive and negative power supplies, and the absolute values of the positive and negative saturated output voltages Vs are equal. First, a state in which the signal magnetic field Hs is not applied to the magnetic core 11 will be described. Now, suppose that the operational amplifier 10 is positively saturated and the output voltage is V. is in a state of +Vs, the operational amplifier 10
A positive saturated output voltage V is present at the non-inverting terminal of . is input as a reference voltage signal V3 divided by the resistance ratio of the resistor 14 and the resistor 15. On the other hand, the impedance of the first winding 12, which operates as a nonlinear inductance element, is determined by the fact that the magnetic flux state of the magnetic core 11 is in an unsaturated magnetic flux state and in the positive direction (hereinafter, the current flowing through the nonlinear inductance element when the output voltage of the operational amplifier is positive). The positive direction is the direction in which the voltage is excited by As shown in the positive half cycle period of FIG. 4A, the voltage waveform of the operational amplifier 10 remains in the positive saturation state for a while. However, since the magnetic core 11 has nonlinear characteristics, when the magnetic flux level increases and approaches a positive saturation magnetic flux state, the nonlinear inductance element of the first winding 12 becomes a mere first winding without the magnetic core 11. As the impedance of the first winding 12 decreases, it approaches the characteristics of a linear inductance element due to
The voltage V1 at the first node 12 increases, and the state changes from the state of V3 to V1=V', which corresponds to the state indicated by 4 in FIG. 4a. And V1>V3
The polarity of the input voltage signal V3-V1〉0 that has been applied to the operational amplifier 10 changes from positive to negative V3-V1〉0 at the moment when the output voltage of the operational amplifier 10 changes. .
is saturated and becomes negative -Vs, and at the same time, the sign of the reference voltage signal at the third node is also inverted. In FIG. 4a, this is the portion corresponding to 8. Therefore, the magnetic core 11 is excited in the opposite direction and enters the unsaturated magnetic flux state again. This is the fourth
This period corresponds to period O in Figure a. In this negative excitation period,
The impedance of the first winding 12 becomes large again, and the impedance of the first winding 12 increases again.
The relationship of V1-■3>0 is established between the voltage V1 at the node and the reference voltage signal V3 at the third node.The L-arithmetic amplifier 10 continues to output the negative saturated output voltage -Vs. Become. This state continues until the magnetic core 11 reaches a negative saturation magnetic flux state. Next, as the magnetic flux level gradually decreases and approaches the negative saturation magnetic flux level, the impedance value of the first winding 12 decreases for the same reason as described above - the voltage V1 at the first node 12 becomes a deep negative voltage. Therefore, at the next moment, V1 is present between the negative reference voltage signal V3 and V1 at the third node.
-V3<0 is established, and the input voltage signal V of the operational amplifier 10
1-V3 changes from positive to negative voltage (part 9 in Figure 4a), and the operational amplifier 10 has a positive saturated output voltage +V.
It enters the positive excitation period again to output s, and thereafter this operation is repeated to maintain magnetic oscillation. In this case, the voltage waveform observed at the second node 22 is V in FIG.
. It is a waveform, and its average DC voltage value (■) is zero because there is no external magnetic field. Next, a case will be described in which the signal magnetic field Hs exists and is applied in the positive excitation direction of the magnetic core 11, causing the magnetic core 11 to be biased.

Now, the operational amplifier 10 is positively saturated and the output voltage is V.

becomes +Vs, then the sum Hs+Hd of the signal magnetic field Hs>0) and the excitation magnetic field Hd (>0) generated by the positive current flowing through the first winding 12 is the positive excitation of the magnetic core 11. Since the signal magnetic field Hs becomes a magnetic field, the positive magnetic flux saturation state is reached earlier than when the signal magnetic field Hs does not exist. Therefore, Figure 4b
As shown during the positive half cycle of the figure, the operational amplifier 10
The period during which the positive saturation state is maintained becomes shorter. On the other hand, the period during which the operational amplifier 10 remains in a negative saturation state is
Since the magnetic field of the sum Hs+(-Hd) of the signal magnetic field Hs (>O) and the magnetic field -Hd generated by the negative current flowing in the first winding becomes the negative excitation magnetic field, the signal magnetic field Hs does not exist. In this case, the strength of the excitation magnetic field becomes weaker, and as a result, the negative flux saturation state is reached later. Therefore, Figure 4b
As shown, the duration of the negative excitation half cycle, ie, the duration of the negative saturation of operational amplifier 10, is increased. Thus,
As shown in FIG. 4b, the radio waveform at the second node 22 is the output V of the operational amplifier. It can be seen that in the second embodiment described above, the average DC voltage ■ is controlled by the signal magnetic field Hs, as in the first embodiment. However, since the capacitor 16 exists, the voltage waveform between the terminals 24 and 25 is different from the signal magnetic field H.
It will be observed as a waveform in which a triangular wave is superimposed on the average current voltage that has been subjected to magnetoelectric conversion of s. This is also observed as the inter-terminal voltage at the terminals 17 and 18 in the first embodiment. As described above, according to the present invention, depending on the presence or absence or change of the signal magnetic field Hs, a difference is caused in the saturation duration of the positive and negative outputs of the operational amplifier 10, and thus the output V.

The average DC voltage V. is controlled by the signal magnetic field Hs. In Figure 5, the horizontal axis is the signal magnetic field HS1, and the vertical axis is the average DC voltage V
.

As, typical signal magnetic field Hs and average DC voltage V. shows the relationship between By applying the signal magnetic field Hs in the positive direction, the output V of the operational amplifier is increased. It has been shown that the positive saturation duration of L is earlier and the negative saturation duration of saturation L is later, and this difference in duration produces a negative average DC voltage. For ease of explanation, the voltage waveform explanatory diagrams in Figures 2a and b and Figures 4a and b are shown when the magnetic field Hs is zero or when a signal magnetic field is applied. This was explained using an example in which the period of periodic repetition does not change.

As described above, the present invention provides a device for controlling the duration difference between the positive and negative saturation output voltages of the operational amplifier 10 using the signal magnetic field Hs.
Depending on the circuit conditions, such as when the gain of 0 is small, when the magnetic core 11 is used in an unsaturated region, when the slew rate is poor, the output voltage waveform of the operational amplifier 10 becomes a trapezoidal wave or a triangular wave, and the DC voltage changes. It should be noted that these events do not go beyond the scope of the present invention.

[Brief explanation of the drawing]

FIG. 1 is an electrical circuit diagram of the first embodiment of the device of the present invention, and FIG.
3 is an electrical circuit diagram of the second embodiment of the device of the present invention, FIG. 4 is an explanatory diagram of waveforms, and FIG. 5 is an explanatory diagram showing the relationship between the signal magnetic field and the average DC voltage. . 1, 2, 3, 4... Node point, 1', 22, 32, 4'
．． ... Node point, 10. ... Arithmetic amplifier, 11... Magnetic core, 12... First winding, 13, 14, 15... Resistor,
16. ．． ．． Capacitor, 17, 18, 19, 24, 25
．． ．． ．． Terminals 20 and 21, 22 and 23... A pair of terminals for the second winding.

Claims (1)

[Claims] 1. An operational amplifier, a nonlinear inductance element including a magnetic core and a first winding wound around the magnetic core, a first resistor connected in series to one terminal of the nonlinear inductance element, and a first resistor connected in series to one terminal of the nonlinear inductance element. a capacitor connected in parallel between both terminals of the first resistor; a second resistor connected in series with the other terminal of the first resistor; and a capacitor connected in series with the other terminal of the second resistor and the other terminal of the nonlinear inductance element. The third
A nonlinear inductance element, a parallel connection of a first resistor and a capacitor, a second resistor, and a third resistor constitute a circular circuit, and a node between the second resistor and the third resistor, a nonlinear inductance element, and a nonlinear inductance element. The node between the first resistor and the parallel connection of the capacitor is connected to the two input terminals of the operational amplifier, and the node between the second resistor and the parallel connection of the first resistor and the capacitor is connected to the output terminal of the operational amplifier. A magnetic control device characterized by being connected to. 2. An operational amplifier, a magnetic core, a nonlinear inductance element consisting of a first winding wound around the magnetic core, a first resistor connected in series to one terminal of the nonlinear inductance element, and both terminals of the first resistor. a second resistor connected in series to the other terminal of the first resistor; and a third resistor connected in series to the other terminal of the second resistor and the other terminal of the nonlinear inductance element.
A nonlinear inductance element, a parallel connection of a first resistor and a capacitor, a second resistor, and a third resistor constitute a circular circuit, and a node between the second resistor and the third resistor, a nonlinear inductance element, and a nonlinear inductance element. The node between the first resistor and the parallel connection of the capacitor is connected to the two input terminals of the operational amplifier, and the node between the third resistor and the nonlinear inductance element is connected to the output terminal of the operational amplifier. Features magnetic control device. 3. The magnetic control device according to claim 1, wherein one second winding for current input is wound around the magnetic core. 4. The magnetic control device according to claim 1, wherein two or more second windings for current input are wound around a magnetic core. 5. The magnetic control device according to claim 2, wherein one second winding for current input is wound around the magnetic core. 6. The magnetic control device according to claim 2, wherein two or more second windings for current input are wound around the magnetic core.