JPH0664169U - Current detector - Google Patents

Abstract

(57) [Abstract] [Object] The present invention relates to a device for detecting a current by the action of a magnetic field generated by a current flowing through a conductor, and a current detecting device improved so that a current without error can be detected even at a distance of a current detection point. The purpose is to provide. In a current detecting device for detecting a current based on an action of a magnetic field generated by a current flowing through a conductor, a magnetic sensitive element incorporated by cutting a part of a magnetic core forming a magnetic path of the magnetic field, An amplifier for amplifying the voltage induced by the magnetic sensing element and a digital signal conversion means for converting the output voltage of the amplifier into a digital signal are provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a current detection device that detects a current based on the action of a magnetic field generated by a current flowing through a conductor.

[0002]

[Prior art]

 A conventional example of this type of current detection device will be described with reference to FIG. FIG. 4 shows the same construction as Japanese Utility Model Application Laid-Open No. 2-57069, in which 1 is a magnetic sensitive element such as a Hall element incorporated by cutting a part of a magnetic core, and 20 is a magnetic sensitive element 1. A power supply circuit for applying a voltage to the magnetic field sensor 21 and a differential amplifier 21 for amplifying the voltage induced in the magnetic sensing element 1.

As shown in FIG. 3, the magnetic sensing element 1 is assembled by cutting a part of a magnetic core 22, and a conductor 23 penetrates the magnetic core 22. When a current flows through the conductor 23, a magnetic field proportional to the flowing current is generated, and in the generated magnetic field, the magnetic core 22 forms a magnetic path to give a strong magnetic field to the magnetic sensing element.

When a magnetic field is applied to the magnetic sensitive element 1, a voltage proportional to the applied magnetic field is induced in the pickup terminal of the magnetic sensitive element 1. That is, a voltage proportional to the current flowing through the conductor is generated. Since the generated voltage is weak, it is amplified by the differential amplifier 21 and output.

[0005]

[Problems to be solved by the device]

 As described above, the conventional current detection device amplifies the voltage induced by the magnetic sensitive element and outputs it as the detected current. Therefore, when trying to know the detected current value from a distance, it is necessary to transmit a signal through the transmission line.

When a transmission line is connected, a voltage drop occurs due to the resistance of the transmission line, resulting in an increase in error, and there is a problem that noise from the outside is mixed and the error increases. An object of the present invention is to provide an improved current detection device that does not cause an error even if the detection point is distant.

[0007]

[Means for Solving the Problems]

 Means adopted by the present invention to solve the above problems will be described. In a current detection device for detecting a current based on an action of a magnetic field generated by a current flowing through a conductor, (a) a magnetic sensing element incorporated by cutting a part of a magnetic core forming a magnetic path of the magnetic field. (B) An amplifier for amplifying the voltage induced by the magnetic sensitive element, and (c) a digital signal converting means for converting the output voltage of the amplifier into a digital signal.

[0008]

[Action]

 A voltage proportional to the current flowing through the conductor is induced from the magnetic sensing element. The amplifier amplifies the voltage induced by the magnetic sensing element. The digital signal converting means converts the voltage amplified by the amplifier into a digital signal and outputs the digital signal.

As described above, the voltage induced by the magnetic sensing element is amplified and converted into a digital signal for output. Therefore, even if the detection point is distant, the digital signal is reproduced so that the transmission line It is possible to eliminate the influence of noise from the resistance and the outside, and it is possible to perform current detection without error.

[0010]

【Example】

 An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram of the first embodiment, and FIG. 2 is a block diagram of the second embodiment. First, a first embodiment will be described with reference to FIG.

In FIG. 1, 1 is a magnetic sensing element, 2 is an amplifier, 3 is a voltage controlled oscillator (VCO), 4 is a slicer, 5 is a transmission line, and 6 is a frequency voltage converter. As described with reference to FIG. 3, the magnetic sensing element 1 is incorporated by cutting a part of the magnetic core, and a voltage proportional to the current flowing through the conductor is output from the pickup terminal.

The weak voltage induced by the magnetic sensing element 1 is amplified by the amplifier 2 and input to the voltage controlled oscillator (V CO) 3. The VCO 3 changes the oscillation frequency according to the input voltage value. The slicer 4 slices the amplitude of the signal output from the VCO 3 to generate a pulse and sends it to the transmission line 5.

The frequency-voltage converter 6 receives the pulse transmitted by the transmission line 5, and outputs a voltage value corresponding to the repetition frequency of the received pulse. Therefore, a voltage proportional to the current flowing through the conductor is output to the output of the frequency-voltage converter without being affected by the resistance of the transmission line or external noise.

Although the pulse repetition frequency is modified by the VCO and slicer in the embodiment, the means for changing the pulse repetition frequency is not limited to this embodiment. Next, a second embodiment will be described with reference to FIG.

In FIG. 2, the magnetic sensing element 1, the amplifier 2 and the transmission line 5 are as described in FIG. Further, 10 is an analog-digital converter (A / D), 11 is a parallel-serial converter that converts the digital signals output in parallel from the A / D 10 to serial, and sends out to the transmission line 5, 12 is the transmission line 5 A serial-parallel converter 13 for converting a transmitted digital signal in parallel is a digital-analog converter (D / A).

The voltage induced by the magnetic sensing element 1 is amplified by the amplifier 2 and converted into a digital value by the A / D 10. The parallel-serial converter 11 converts the parallel digital signal output from the A / D 10 into a serial digital signal and sends it to the transmission line 5.

The parallel-serial converter 12 receives the digital signal transmitted via the transmission line 5, converts it into a parallel digital signal, and outputs it to the D / A 13. Therefore, a voltage proportional to the current flowing through the conductor is output to the output of the D / A 13 without being affected by the resistance of the transmission line or external noise.

Although the pulse repetition frequency and A / D are used as the means for converting the pulse signal in the embodiment, the pulse width is changed as the method for converting the output voltage from the amplifier into the pulse signal. The changing method and the pulse position may be changed.

Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and various modifications can be made according to the gist of the invention.

[0020]

[Effect of device]

 As described above, according to the present invention, the following effects can be obtained. The voltage induced by the magnetic sensing element is amplified and converted into a digital signal for output, so that even if the detection point is distant, by reproducing the digital signal, the effects of transmission line resistance and external noise Can be eliminated, and current can be detected without error.

[Submission date] June 3, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

In the experimental example, the pulse repetition frequency was changed by the VCO and the slicer, but the means for changing the pulse repetition frequency is not limited to this embodiment. Next, a second embodiment will be described with reference to FIG.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a second embodiment of the present invention.

FIG. 3 is an explanatory diagram of an assembled state of the magneto-sensitive element of the embodiment.

FIG. 4 is a configuration diagram of a conventional example.

[Explanation of symbols]

 1 Magnetic Sensitive Element 2 Amplifier 3 Voltage Controlled Oscillator (VCO) 4 Slicer 5 Transmission Line 6 Frequency Voltage Converter 10 Analog-to-Digital Converter (A / D) 11 Parallel-series Converter 12 Series-parallel Converter 13 Digital-analog Converter (D) / A)

Claims (3)

[Scope of utility model registration request] 1. A current detecting device for detecting a current based on an action of a magnetic field generated by a current flowing through a conductor, wherein: (a) a magnetic core forming a magnetic path of the magnetic field is partially cut and incorporated. A magnetic sensitive element, (b) an amplifier for amplifying the voltage induced by the magnetic sensitive element, and (c) a digital signal converting means for converting the output voltage of the amplifier into a digital signal. Current detection device. 2. The current detecting device according to claim 1, wherein the digital signal converting means is composed of a voltage pulse frequency converter that changes the pulse repetition frequency in accordance with the output voltage of the amplifier. 3. The current detecting device according to claim 1, wherein the digital signal converting means is composed of an analog-digital converter which converts a digital value corresponding to an output voltage of the amplifier.