JPS5946860A - Voltage-current detector - Google Patents

Abstract

PURPOSE:To decrease parts and to reduce space, by constituting an annular iron core of the 1st coil which is connected in series in the mid-way of a closed loop and is used for detecting electric current, the 2nd coil which is connected in parallel with a switching circuit and is used for detecting voltage, and the 3rd coil which is magnetically coupled to the 1st and the 2nd coils. CONSTITUTION:The large current 10 from an AC power source 6 returns through the route of a load 12 the 1st coil 15 a switching circuit 13 or the reverse route to an AC power source 11 while the circuit 13 is held conducted. Therefore, the current i0 flowing in the closed loop is detected by the coil 15 and the detected output is led out to the 3rd coil 17. The small current i1 from the power source 11 returns through the route of the load 12 the coil 15 the 2nd coil 16 a resistor 18 or the reverse route to the power source 11 while the circuit 13 is held cut off. The voltage between both terminals of the circuit 13 is thus detected by the coil 16. The detected output is led out to the coil 17. Thus, the parts for detecting the current and voltage are unified, and the space for the detection is made as small as possible.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to voltage/electricity ITt+m installation and purchase, and more specifically, a switching circuit is connected to an AC power source and a load in a closed loop, and the switching mode of the switching circuits il and I is changed. In order to detect the timing when the switching circuit is turned on, the current flowing through the closed loop is detected when the switching circuit is turned on, and the voltage across the switching circuit is detected when the switching circuit is cut off.
This invention relates to a current detection device.

Referring to FIG. 1, in the prior art,
A switching circuit 8 is connected to the load 2 in a closed loop. In order to detect the timing for changing the switching mode of the switching circuit 3, a current detector CT detects the current flowing in the closed loop when the switching circuit 3 is turned on, and a voltage across the switching circuit 3 when the switching circuit 3 is turned off. A l'E detector PT is provided to detect...l'E detector PT. Outputs from current detector CT and pressure detector PT are given to drive circuit 4. The drive circuit 4 operates the switching circuit 3 at desired timing in response to outputs from the current detector CT and the voltage detector PT.
change the switching mode to the desired switching mode. However, two of the current detector CT and voltage detector PT
are used individually, the number of parts is large, and the space for the current detector CT and voltage detector PT is large.

An object of the present invention is to provide a voltage/current detection device that solves the above-mentioned technical problems, reduces the number of parts for detecting current and voltage, and minimizes the space as much as possible. It is to be.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 2 is a circuit diagram of one embodiment of the present invention. Alternating current@
A switching circuit 13 is connected to @ 11 and a load 12 via a closed loop. Annular iron core ■4iL has a first coil 15, a second coil 16, and an eighth coil 17. The first coil 15 is connected in series in the middle of the closed loop. The second coil 16 is connected in series with a resistor 18 having high impedance. The second coil 16 and resistor 18 are connected to a switching circuit. 13 and 11ρ columns.

The eighth coil 17 is in contact with the drive amount WF19 and is 11:.

A third coil 17 is magnetically coupled to the first and second coils 15 and 16. The drive circuit 19Vi changes the switching mode of the switching circuit [18] to a desired switching mode at a desired timing in response to the output from the third coil 17.

When the switching circuit 13 is conductive, a large current i0 from the AC power supply 6 returns to the AC power supply 11 through the path of the coil 15--the switching circuit 13 or the opposite path from t. Therefore, the current flowing in the closed loop, 10, is detected by the first coil 15, and a detection output is derived to the third coil 17.

When the switching circuit 13 is cut off, a small current if from the AC power source 11 returns to the AC power source 11 via the reverse path of the load 12, the first coil 15, the second coil 16, and the resistor 18. Therefore, the voltage across the switching circuit I3 is detected by the second coil 16, and a detection output η is derived to the third coil 17.

Note that if the impedance of the second coil 16 is large, the resistor 18Vi may be omitted. Further, another coil may be provided on the annular core 14 and connected to the drive circuit I9. Moreover, the switching circuit 13 is
The circuit may include a relay switch 20, 21 and a diode 22 as shown in FIG. 3, a circuit such as an analog switch, or a switching element such as a thyristor. Good too. In addition, it is only necessary to penetrate the inside of the annular iron core 14 by inserting the first coil (5).

As described above, according to the present invention, it is possible to use a single component for detecting current and voltage, and the space therefor can be legally reduced.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of the prior art, FIG. 2 is a circuit diagram of an embodiment of the present invention, and FIG. 3 is a diagram showing an example of the switching circuit 13. 11... AC power supply, 12... Negative? llr, l 3・
...Switching circuit, 14...Annular iron core, 15...
・1st coil, 16...2nd coil, 17...3rd coil
Coyle agent Patent attorney Kei Nishi Department part Figure 1 1 L ------J Figure 2 1 Figure 3

Claims (1)

[Claims] A switching circuit is connected to an AC power source and a load in a closed loop, and in order to detect the timing of changing the switching mode of the switching circuit, a current flowing through the closed loop is detected when the switching circuit is conductive. In addition, in the voltage/current detection device configured to detect the voltage between both ends of the switching circuit when the switching circuit is cut off, the device is connected in series in the middle of the closed loop: 11. a first coil for detecting the current; a second coil having high impedance and connected in parallel to the switching circuit for detecting the voltage;
and a toroidal core having a third coil magnetically coupled to @l and the second coil.