JPS5949682B2 - Metamorphosis device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transformer that can respond to either direct current or alternating current input.

Conventionally, as means for detecting direct current and voltage in an insulated state, a direct current transformer and a direct current transformer using a pair of saturable reactors have been used.

However, with this method, it is difficult to distinguish the polarity of the detected current and voltage source, and if the polarity is to be detected, it is necessary to There was no other choice but to judge by the phase of the induced voltage in the line. Further, a Hall element is also used as the above-mentioned discrimination method, but even with this method, satisfactory accuracy cannot be obtained because the characteristics change depending on frequency, temperature, etc.
On the other hand, AC transformers have the disadvantage that they lose their operational function in response to DC components in the low frequency range. The present invention has been made to eliminate the above-mentioned drawbacks of the conventional transformer, and aims to expand the applicable frequency range of magnetically coupled transformers.

Hereinafter, the device of the present invention will be described in detail with reference to the illustrated embodiment. In FIG. A transformer consisting of a second winding N2 that also serves as an excitation conductor, and a third winding N3 for voltage detection that responds to changes in magnetic flux; 2 is an induced voltage induced in the third winding N3 for detecting magnetic flux voltage of the transformer 1; An amplifier with a nearly instantaneous gain, which takes as input, integrates the value over time, and outputs it, and resistors Ri and R
r, an integrator consisting of a capacitor Cf, and 3 is the output voltage V of this device.

A resistor R connected across the terminals to obtain , a ripple detection section mainly consisting of a resistor Rp and a capacitor Cp, which have the functions of detecting the ripple component of the voltage between the terminals and removing low frequency components, and an amplifier As and resistors R, , R.
ripple detection means consisting of an amplifying section according to 2;
is the addition part of resistors RAI and RA2 and the operational amplifier A4
and a comparison judgment part with a threshold value using resistors Ru, R,
This excitation means has an input level determination function and a power amplification function, which is comprised of output portions of positive and negative predetermined voltages from the conversion amplifier A1. Next, FIG. 2 is an explanatory diagram of the dynamics of the magnetic flux generated in the magnetic core CO of the transformer 1 shown in the circuit of FIG. The operating state of the circuit of FIG. 1 when electricity is applied is shown by waveforms over time. Incidentally, the integrator 2 in FIG. 1 can be replaced by a simple resistor-capacitor circuit depending on the required function, and in this case, the amplifier A2 is not necessarily required. Further, the amplifier A3 of the ripple detection means 3 also detects the detection input voltage and the excitation means 4.
Depending on the state of the input sensitivity, the switching amplifier A1 of the excitation means 4 can also be replaced with a semiconductor switch, a power amplifier, or the like. The operation of the circuit shown in FIG. 1 configured as above will be explained. Now, T shown in FIG. 3b. Before the time , the current source SI applies a current Is in the direction shown, and the magnetic core CO of the transformer 1
When the magnetic flux is at point P1 of the solid line shown in Figure 3d, the above T
. To explain the state in which the output voltage of the input summing power amplifying section of the excitation means 4 is switched from negative to positive when the time reaches the time shown in FIG. , which produces an induced voltage value corresponding to that voltage in the N3 winding. Further, the N3 winding voltage is integrated by an integrator 2, and its output voltage V2 is a predetermined negative voltage value V2O (third
From Figure e), it gradually increases over time. On the other hand, magnetic core C
The magnetic flux φ of O is shown in Figure 3 DC! ) P, gradually decreases from the 3rd point.
Figure d (:!) Go to point P3 via point P2.

During this period, when the current in the N3 winding is very small and can be ignored, the current Is flowing through the winding N1 flows through the second winding N2 in the direction of the indicated current 12, and this current is supplied from the amplifier A1 and is resisted by the resistor. Vessel R. flows. Therefore, N1 turns number of steps 2 = - x number of steps. So, N2 turns resistor R.

The voltage drop is V. = ROXl2. That is, the output of the transformer shown in FIG. 1 has a value proportional to the input current. Further, in the direction from point P2 to point P3 in FIG. 2, the exciting current due to the magnetic flux φ of the transformer core CO increases, resulting in an output of V. As shown in Figure 3f, increases with the passage of time, the ripple also
p, is amplified by amplifier A3, and becomes the output voltage V3,
The state shown by the solid line in FIG. 3c is reached. At this time, integrator 2
The output voltage V2 becomes the voltage value V2A (Fig. 3e(1)).
In this way, the above output voltage V input to the excitation means 4
2, V3 becomes Vad by adding the above output voltages V3A and V2A by addition resistors RAI and RA2, and outputs it to amplifier A.
Positive threshold value 1 set by resistors Rf and Ru of 4
Once Vth is exceeded, the output of switching amplifier A1 changes from positive to negative and the threshold changes to ΘVth.

To explain the above operation in more detail, if the negative phase input impedance of the amplifier A4 in the excitation means 4 is almost infinite, then (
In practice, there is no problem considering this), and its terminal voltage Vad
is as shown in the following formula.

Hereinafter, the resistance value of each resistor will be expressed using the same symbol as its symbol, and the voltage value will be expressed including its symbol. That is, the voltage Vad has a value proportional to the sum of the output voltage V2 of the integrator 2 and the output voltage V of the ripple detection means 3.

If the output voltage of amplifier A4 is V4, the threshold voltage V
th can be expressed as follows. When the value Vad expressed in the above equation (3) exceeds the value Vth in the equation (4),
Due to the action of the positive feedback hysteresis amplifier mainly composed of the amplifier A4, the polarity of the output voltage V4 of the amplifier A4 is reversed, and the output polarity of the conversion amplifier A1 is also reversed.

As a result, the voltage applied to the secondary winding N2 of the transformer 1 is reversed, and the direction of change of the magnetic flux φ is thus reversed.In this way, the output of the excitation means 4 is Each time the sum exceeds a predetermined threshold value Vth, the polarity is alternately reversed. Here, in the integrator 2, the input is the winding N
If this value is N3, this value is roughly proportional to the value applied to the N2 winding.

Since the positive phase input terminal of amplifier A2 is at ground potential, the negative phase input terminal is also always at ground potential, that is, resistor Ri
The current flowing through is proportional to the VN3 voltage. Since the current flowing through capacitor Cf is equal to the current flowing through resistor Ri, output voltage 2 of amplifier A2 is equal to capacitor Cf.
The value is proportional to the amount of charge accumulated in (Q=It).
In other words, the 2 voltages indicate the time integral value of the N3 voltage. That is,
It can also be said that the two voltages are proportional to the time integral value of the voltage N2 applied to the secondary winding. By the way, what is important here is that the time-integrated value of the voltage applied to the N2 winding as the N2 voltage is the total amount by which the magnetic flux has changed with respect to the transformer 1. For example, T in Figure 3b. The time-integrated value of the N2 voltage during time -t1 is the magnetic flux change at points P1 to P3 in d of the figure. Since the N2 voltage is constant, the magnetic flux change is also linear. In FIG. 2, this corresponds to the change in the amount of the vertical axis component regarding the change in the solid line points P1→P2→P3 on the hysteresis diagram. In other words, to summarize the above, it can be said that the output voltage 2 of the integrator 2 is an output proportional to the amount of change in the magnetic flux of the transformer 1.

When there is only this integrator 2 and no ripple detection means 3, for example, the magnetic flux φ is φ in FIG. Draw a loop. In other words, a hysteresis loop is drawn in which the amount of change in magnetic flux in the vertical direction is equal. But at the same time, this
It also shows that the hysteresis loop can easily move up or down. If there is an offset in the amplifier A2 in the integrator 2, the output of the integrator 2 will push the magnetic flux φ upward or downward by an amount proportional to the amount of offset, and in a direction that matches the sign of the offset. . In Figure 2, if it shifts upward, the loop of φe, and if it shifts downward, the loop of φo
For example, if a loop is drawn and an attempt is made to move above or below this, the magnetic flux reaches saturation and the excitation current increases rapidly.
Since this can be detected as a voltage drop across the resistor, the ripple detection means 3 detects the rapidly increasing change, and the output of this means forcibly reverses the output polarity of the excitation means 4. Thus, the magnetic flux is pulled back toward unsaturation rather than saturation. Here, the amount of magnetic flux that shifts upward or downward is
The offset value mentioned above is usually small, so it does not move up or down very much. If the magnetic core is to be excited for the first time, or if the magnetic core is positively or negatively saturated by a magnetic core inspection before normal use, it will operate in a biased state of φ1 or φe as shown in Figure 2. It's possible. For example, in such a case, the ripple detection means exerts a force, but as soon as it is biased upward or downward, the magnetic flux becomes φ. It doesn't come back to the loop that becomes. This is because the amount of change in magnetic flux in the positive and negative directions is the same for both φe and φe, as in the case of φo.
However, although the magnetic flux is gradually increasing, when the amount of excitation in both the positive and negative directions is equal, there is no basis for unnecessarily biased magnetization, so φ.
Return to loop. Thus, the voltage N2 applied to the second winding N2 of the transformer is reversed at point P3 due to the rapid increase in the output V3 of the ripple detection means 3, as shown in FIGS. 2 and 3d.

Furthermore, at time T2 when the point P1 is reached after passing through the P4 point, the output 2 of the integrator 2 becomes a negative predetermined magnitude, and the voltage V
2 and the output voltage 3 of the ripple detection means 8
When d reaches the threshold value Ev,h, the amplifier A1
The output voltage of is reversed, and the operation is repeated in the same manner. Incidentally, since the magnetic flux φ of the magnetic core CO at point P1 does not reach saturation, and therefore the output voltage V3 of the ripple detection amplifier section is also low, the operation of reversing the output voltage of the switching amplifier A1 is performed by the integrator 2. , the ripple detection means 3 only performs a small corrective action auxiliary at the time of excitation polarity switching.
When the magnetic flux draws a loop of φ4 as shown by the dotted line in FIG. 2, each part operates according to the waveform shown by the dotted line in FIG. In this case, the integrator output value level at the time of polarity reversal shifts compared to the solid waveform when the magnetic flux traces the loop φe described above. That is, when the negative bias magnetic loop φe operation is attempted, the time point t1 is brought forward,
T2 time point is delayed. When the positive polarized magnetic loop φe operation is attempted, the time point t1 is delayed and the time point t1 is brought forward. Thus, the residence time at each polarity is modified so that the normal operating loop φ. will be taken back to. others,
Along with various uncertain factors, this prevents drifting in the positive and negative polarized magnetic loop directions. Note that, as described above, once the magnetic flux is biased positively or negatively due to the uncertain element of the magnetic flux, it does not immediately return to the state where it is excited at the center of hysteresis. When the magnetic flux is positively biased, the magnetic flux operates as shown by the dotted line V in FIG. Next, the output current 1 of the detected current power source SI. When the polarity changes,
The current 12 flowing through the second winding N2 also undergoes a polarity change, but this second winding N2 is not affected by the voltage polarity of the converter amplifier A1 and is applied to the first winding as shown in FIG. The output voltage V has a polarity that matches the polarity of the current Is.
is obtained. As mentioned above, the circuit shown in FIG. 1 uses the integrator 2, the ripple detection amplifier 3, and the excitation means 4 to invert the excitation voltage polarity of the transformer 1 at predetermined time intervals, so that the magnetic core flux is constantly kept in the unsaturated region. , the magnetomotive force between the first winding and the second winding is kept in a proportional state, so that an instantaneous value with less ripple can be obtained.

It goes without saying that the same effect can be obtained even if Rx is connected to the input side of the integrating circuit 2. Thus, according to the above configuration, not only bipolar detection is possible, but also both AC and DC currents can be detected, and the applicable frequency range can be widened. Next, another embodiment of the present invention will be explained based on FIG. 5, FIG. 6, and FIG. This is a rectifier circuit consisting of series bodies connected in parallel, which rectifies the peak values of the positive and negative outputs of the amplifier, and is used to accumulate the output of the ripple detection means 3 for a short time. Further, other symbols in the figure represent the same parts as shown in FIG. FIG. 6 is a diagram explaining the operation of the magnetic core flux of the transformer 1 shown in FIG. 5, and FIG. 7 shows the operating state of each part in FIG. 5 over time. At time tl, current source SI generates current Is
flows in the direction shown in FIG. 5, the magnetic flux φ of the magnetic core CO is at point P3 in FIG.
The V2O shown in Figure b.

On the other hand, the added value Vad of the rectified voltages Vp and Vv in FIG.
This is represented by point V3A in Figure e. Here, the integrator 2 in FIG. 5 has a different sign from that in FIG. 1.

The integrator shown in FIG. 1 has a circuit configuration in which when a positive input is received, the output gradually changes in the negative direction. In FIG. 5, the negative sign is removed and S is shown, so the polarity of the hysteresis of the excitation means 4 is also reversed.

These added voltages Vad are input to the excitation means 4,
When the positive hysteresis voltage Vt... is exceeded, the output of the excitation means 4 changes from negative to positive.

As a result, the voltage VN2 of the second winding N2 changes from negative to positive, and the magnetic core moves from point P3 to point P1 in FIG. The voltage accumulation state in the rectifier circuit 5 of FIG. 5 at that time is shown in FIG. 7d as VvA for Cv and VpA for Cp. The electric charges of Cv and Cp are discharged from this voltage through resistors RA2 and RA3, and the absolute value decreases with the passage of time. Next, the output voltage V2O of the integrator 2 also gradually decreases, and the sum VAD of the added voltages VpA and VvA and the added value Vi of the output voltage V2O of the integrator 2 are
When the value exceeds the predetermined value of the hysteresis negative voltage VtΘ, the output of the excitation means 4 turns negative again, and the magnetic flux P
After 2 points, we move on to P3.

Considering the state immediately before reaching time T2, the output voltage V
As shown by the dotted line in FIG. 7g, the ripple voltage gradually decreases, and the output voltage V3 of the ripple detection amplifier A3 reaches the Tth
It gradually increases as shown in Figure c. This is capacitor C
When the holding value of p is exceeded, the terminal voltage Cp increases rapidly and V
The sum value voltage Vad with v also increases. Then, the above-mentioned addition voltage Vad and the integrator 2 output V2 are added and the excitation means 4
This leads to the inversion of the output voltage Ve. Now, as time T3 approaches, the output voltage V. As increases the ripple voltage in the negative direction, the negative peak value rectifier capacitor voltage Vv
increases rapidly, the voltage Vp and the added voltage value Vad suddenly decrease, and the output voltage of the excitation means 4 is again inverted from negative to positive. Thereafter, the same operation is repeated in this way, and each time the amount of movement of the magnetic flux reaches a predetermined value, the excitation voltage polarity is reversed to perform magnetic coupling oscillation. , automatically correct the excitation voltage switching point.

The input action in the transformer and the responsiveness of the magnetic poles are the same as in the case of FIG. 1 above. The reason why the magnetization is biased positively or negatively is the same as that explained in FIG.

Converges to a loop. This is shown by the solid lines and dotted lines in Figure T gradually converging toward the center. The magnetic core of FIG. 6 is made of a material such as soft ferrite and has a gentle vφ-AT curve, while the rectangular material of FIG. 2 has a steep φ-AT curve. Even if a magnetic core as shown in FIG. 6 is biased, it will quickly return to the center if the cause of the bias is removed. The average value output voltage A of the voltages V, , Vv of the rectifier circuit 5 according to the other embodiment shown in FIG. 5 is shown by the dotted line in FIG. It goes without saying that it may be added to the input side of the integrator 2 in such a manner as to provide a correction input for its operation, as shown.

Moreover, the ripple detection means 3 outputs voltage V. This amplifies the ripple component generated in the AC component, but it can also reduce the ripple output as an alternating current component.
In addition, when the input power source mainly consists of voltage instead of current, apply voltage to the N1 winding through a high resistance,
Of course, if it is made to pass a current proportional to the voltage, it can also function as a voltage transformer. In addition, in cases where other control elements (not shown) are controlled by the output of this transformer, this transformer can also be operated as a power source for supplying these control elements, and it can be operated independently. The present invention has the advantage of not requiring a separate AC power supply. As described above, the present invention is mainly composed of a single-core transformer, and outputs an isolated output with a polarity corresponding to the input current over a wide frequency band. It has a detectable effect.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an embodiment of the transformation device of the present invention;
The figure is a diagram showing the dynamics of the magnetic flux generated in the transformer in Figure 1, Figure 3 is a diagram explaining each part of the transformer in Figure 1 according to changes over time, and Figure 4 is a diagram showing the dynamics of the magnetic flux generated in the transformer in Figure 1. 5 is a circuit diagram showing another embodiment of the transformer of the present invention; FIG. 6 is a diagram showing the dynamics of magnetic flux generated in the transformer of FIG. 5; FIG. 7 is a diagram illustrating each part of FIG. 5 over time. 1...Transformer, 2...Integrator, 3...
... Ripple detection amplifier, 4 ... Excitation means, 5 ... Rectifier circuit, Al, A2, A3, A4.
...Power amplifier, C,, Cf... Capacitor, RO, R,, Rl, R2RA19RA29Ri9
RrRf9Ru2Rx...Resistor.

Claims (1)

[Scope of Claims] 1. A second winding through which a secondary current of a transformer passes, the AC ripple is adjusted so that the output increases or decreases depending on the amount of change over time in the AC ripple component of the second winding current. ripple detection means for amplifying the alternating current component; a third winding wound around the magnetic core of the transformer; an integrating means for inputting the induced voltage to the third winding and integrating it over time; and an output of the integrating means. and excitation means for adding the output of the ripple detection means and reversing the output voltage polarity each time the value reaches a predetermined value of positive and negative polarity to apply an alternate polarity voltage to the second winding of the transformer, A transformation device characterized in that a transformed output is derived from the second winding. 2 A rectifier circuit consisting of a series body of a rectifier and a capacitor connected in parallel between the output terminal of a ripple detection amplifier and the ground, and a rectifier circuit that rectifies the peak values of the positive output and negative output of the amplifier, and the output of this rectifier circuit. 2. The transformer according to claim 1, further comprising a correction circuit that feeds back to said integrating means and corrects the connection point of said excitation voltage polarity.