WO2021186661A1

WO2021186661A1 - Contactless power sensor device

Info

Publication number: WO2021186661A1
Application number: PCT/JP2020/012209
Authority: WO
Inventors: 雄三玉木; 慶洋明星
Original assignee: 三菱電機株式会社
Priority date: 2020-03-19
Filing date: 2020-03-19
Publication date: 2021-09-23
Also published as: JP7034401B2; JPWO2021186661A1

Abstract

A contactless power sensor device (1) equipped with a voltage probe (2), an electric current probe (3) and a sensor circuit (5), wherein: the sensor circuit (5) has a first switch (51) used in the observation of a transient response to a voltage signal observed by the voltage probe (2), a second switch (52) used in the observation of a transient response to a current signal observed by the current probe (3), a switch-driving unit (56) for driving the first switch (51) and the second switch (52), and a processing unit (57) for controlling the driving of the first switch (51) and the second switch (52) by the switch-driving unit (56); and the switch-driving unit (56) generates a positive pulse signal, the amplitude polarity of which is positive, and a negative pulse signal, the amplitude polarity of which is negative, according to the control signal outputted by the processing unit (57), and drives the first switch (51) and the second switch (52) by using the generated positive pulse signal and negative pulse signal.

Description

Non-contact power sensor device

This disclosure relates to a non-contact power sensor device.

In order to observe the AC power to be measured, it is necessary to measure the AC current and AC voltage to be measured. Conventionally, there is a technique for observing an alternating current flowing through a cable conductor and an alternating current voltage applied to the cable conductor without bringing the probe electrode into contact with the core wire of the electric wire. For alternating current, a technique of sensing with a current probe using a magnetic material is known. Further, for AC voltage, a voltage probe using a probe electrode close to an electric wire to be measured is known.

The coupling capacitance generated between the voltage probe and the cable conductor is a minute capacitance estimated by regarding the cable coating that covers the cable conductor as a dielectric. In particular, when the frequency of the observed signal is low, the impedance of the coupling capacitance becomes very high. On the other hand, by observing the transient response signal of the current flowing through the coupling capacitance by turning the switch on and off, accuracy deterioration due to the minute coupling capacitance can be prevented and accurate measurement becomes possible. Become.

For example, the voltage measuring device described in Patent Document 1 measures the AC voltage applied to the measurement target via a detection electrode mounted on the measurement target in a non-contact state. In this voltage measuring device, the current flowing through the coupling capacitance is modulated to a frequency higher than the frequency of the AC voltage by turning the switching element on and off.

JP-A-2017-194420

When measuring the AC power to be measured by using the voltage measuring device described in Patent Document 1, in addition to the driving circuit of the switching element used for measuring the AC voltage, the driving circuit of the switching element used for measuring the AC current. is required. In general, since the drive circuit is a relatively large circuit including a transformer, there is a problem that the device becomes large when two drive circuits are mounted.

The present disclosure solves the above problems, and an object of the present disclosure is to obtain a non-contact power sensor device capable of miniaturization.

The non-contact power sensor device according to the present disclosure observes a voltage probe for observing a voltage generated in a measurement target in a state of non-contact with the measurement target, and a current flowing in the measurement target in a state of non-contact with the measurement target. It includes a current probe and a sensor circuit that calculates the power to be measured using the voltage probe and each signal observed by the current probe, and the sensor circuit is used for observing the transient response of the voltage signal observed by the voltage probe. The first switch, the second switch used for observing the transient response of the current signal observed by the current probe, the switch drive unit that drives the first switch and the second switch, and the first switch drive unit. The switch drive unit has a processing unit that controls the drive of the switch and the second switch, and the switch drive unit outputs a positive voltage signal with a positive amplitude and a negative voltage signal with a negative voltage according to the control signal output from the processing unit. The generated positive voltage signal and the generated negative voltage pulse signal are used to drive the first switch and the second switch.

According to the present disclosure, the switch drive unit generates a positive electrode pulse signal and a negative electrode pulse signal, and drives the first switch and the second switch using the positive electrode pulse signal and the negative electrode pulse signal. Since it is not necessary to separately provide a switch drive unit for AC current measurement and AC voltage measurement, and an increase in the mounting volume of the circuit can be suppressed by that amount, the non-contact power sensor device according to the present disclosure can be miniaturized. It is possible.

It is a block diagram which shows the structure of the non-contact power sensor device which concerns on Embodiment 1. FIG. It is a circuit diagram which shows the equivalent circuit of the switch drive part of FIG. FIG. 3A is a block diagram showing the configuration of the insulation circuit of FIG. 1, and FIG. 3B is a waveform diagram showing the waveforms of signals input and output in the insulation circuit of FIG.

Embodiment 1.
FIG. 1 is a block diagram showing a configuration of the non-contact power sensor device 1 according to the first embodiment. The non-contact power sensor device 1 observes the voltage applied to the cable conductor 6a and the current flowing through the cable conductor 6a, respectively, and observes the AC power. The cable conductor 6a is a core wire in the cable 6, and the cable coating 6b is an insulating coating that covers the cable conductor 6a. An AC power supply 7 is connected to the cable conductor 6a, and a voltage is applied to the cable conductor 6a by the AC power supply 7 to allow a current to flow.

As shown in FIG. 1, the non-contact power sensor device 1 includes a voltage probe 2, a current probe 3, and a sensor circuit 5. The voltage probe 2 and the sensor circuit 5 are connected by a probe cable 41. The current probe 3 and the sensor circuit 5 are connected by a probe cable 42. The voltage probe 2 and the current probe 3 are arranged on the cable conductor 6a to be observed. The voltage probe 2 arranged on the cable conductor 6a and the cable conductor 6a are in a non-contact state due to the cable coating 6b. Similarly, the current probe 3 and the cable conductor 6a are in a non-contact state.

A contactless power sensor device 1, the AC voltage V _in applied to the cable conductor 6a by the AC power source 7, to observe through coupling capacitor C ₀ that occur between the cable conductors 6a and voltage probes 2. _{For example, the coupling capacitance C 0} generated between the voltage probe 2 having a length and width of 1 (cm) and the cable conductor 6a is a minute capacitance of about several (pF).

The sensor circuit 5 drives a first switch 51 used for observing the transient response of a voltage signal, a second switch 52 used for observing the transient response of a current signal, and a first switch 51 and a second switch 52. It is provided with one switch drive unit 56 to be operated. The output of the first switch 51 and the output of the second switch 52 are connected in parallel, and the output AC voltage is divided by the capacitor element 53. Capacitor element 53 is a capacitance _{C 1.}

The AC voltage divided by the capacitor element 53 is input to the positive input terminal of the operational amplifier 54, and is output from the operational amplifier 54 as it is. The operational amplifier 54 is an output operational amplifier in which the negative electrode input terminal is connected to the output terminal and the positive electrode input terminal is connected to the capacitor element 53, and functions as a unity gain buffer amplifier. The AD converter 55 converts an AC voltage analog signal output from the operational amplifier 54 into a digital signal. The output of the AD converter 55 is input to the processing unit 57, and the processing unit 57 calculates and processes the observed value of electric power from the observed values of current and voltage.

In FIG. 1, the switch drive unit 56 controls the drive of two systems, the first switch 51 and the second switch 52. FIG. 2 is a circuit diagram showing an equivalent circuit of the switch drive unit 56 of FIG. As shown in FIG. 2, the switch drive unit 56 includes a bipolar pulse buffer 561, an insulation circuit 562, and a pulse separation circuit 563. The bipolar pulse buffer 561 is a pulse buffer capable of outputting a bipolar pulse signal having a positive amplitude and a negative amplitude according to a signal output from the processing unit 57, and its output end is connected to an insulation circuit 562. Has been done. In the following description, a pulse signal having a positive amplitude is described as a positive pulse signal, and a pulse signal having a negative amplitude is described as a negative pulse signal.

The insulation circuit 562 insulates and transmits the bipolar pulse signal generated by the bipolar pulse buffer 561 to the pulse separation circuit 563. That is, the isolation circuit 562 outputs the pulse signal input from the bipolar pulse buffer 561 to the pulse separation circuit 563 in a state where the bipolar pulse buffer 561 and the pulse separation circuit 563 are insulated.

The pulse separation circuit 563 converts the bipolar pulse signal output from the insulation circuit 562 into a positive electrode pulse signal and a negative electrode pulse signal by a rectifying circuit including the diode element 101 and the diode element 102, and the resistance element 103 and the resistance element 104. To separate.

The system of the first switch 51 is composed of a diode element 101 connected in series and a resistance element 103 connected in parallel, and the diode element 101 to which the bipolar pulse signal is applied to the positive electrode conducts the bipolar pulse signal. Of these, the positive pulse signal is output to the first switch 51 to drive the first switch 51. The system of the second switch 52 is composed of a diode element 102 and a resistance element 104, and the diode element 102 in which the bipolar pulse signal is applied to the positive electrode conducts, so that the negative electrode pulse signal among the bipolar pulse signals is the first. It is output to the second switch 52 and the second switch 52 is driven.

The first switch 51 and the second switch 52 are driven by the positive electrode pulse signal and the negative electrode pulse signal separated by the pulse separation circuit 563. The first switch 51 conducts when a positive electrode pulse signal is applied, and the second switch 52 conducts when a negative electrode pulse signal is applied.

The switch drive unit 56 applies a relatively high gate terminal voltage with reference to the source terminal of the first switch 51 and the source terminal of the second switch 52 by the insulation circuit 562. The pulse separation circuit 563 can generate a positive pulse signal and a negative pulse signal, which are two drive signals, by a rectifying function, and uses the positive pulse signal and the negative pulse signal to generate the first switch 51 and the second switch 51. The on and off of the switch 52 is controlled.

FIG. 3A is a block diagram showing the configuration of the insulation circuit 562. FIG. 3B is a waveform diagram showing waveforms of signals input / output in the insulation circuit 562. As shown in FIG. 3A, the insulation circuit 562 includes a transformer 210 that insulates and transmits the pulse signal output from the bipolar pulse buffer 561 to the pulse separation circuit 563, and the reset circuit 200 is parallel to the primary winding of the transformer 210. Is connected.

The reset circuit 200 is configured by connecting the third switch 201 and the resistance element 202 in series, and waveform-shapes the bipolar pulse signal output from the transformer 210. In FIGS. 3A and 3B, the bipolar pulse signal W1 is a bipolar pulse signal output from the bipolar pulse buffer 561. The reset signal W2 is a reset signal output from the processing unit 57 to drive the third switch 201. The output signal W3 is an output signal generated between the secondary windings of the transformer 210. The third switch 201 switches between inputting and shutting off the bipolar pulse signal W1 output from the bipolar pulse buffer 561 to the reset circuit 200.

Immediately after the positive electrode pulse is input to the transformer 210 and the positive electrode pulse falls and transitions to the off level, a counter electromotive force is generated in the secondary winding of the transformer 210, as shown by the broken line in FIG. 3B. A negative electrode backswing with a very large amplitude occurs in the output signal W3. Further, immediately after the negative electrode pulse is input to the transformer 210 and the negative electrode pulse rises and transitions to the off level, a counter electromotive force is generated in the secondary winding of the transformer 210, as shown by the broken line in FIG. 3B. A positive electrode backswing with a very large amplitude occurs in the output signal W3.

The backswing generated in the output signal W3 causes unintended conduction to the first switch 51 and the second switch 52. In order to prevent this backswing, the processing unit 57 controls the third switch 201 to be conductive during the period when the back electromotive force is generated in the secondary winding of the transformer 210. The period in which the counter electromotive force is generated in the secondary winding of the transformer 210 starts, for example, when the bipolar pulse signal transitions to the off level.

When the bipolar pulse signal has transitioned, the processing unit 57 outputs the reset signal W2 to the third switch 201. The third switch 201 conducts in response to the reset signal W2. When the third switch 201 becomes conductive, the counter electromotive force generated in the primary winding of the transformer 210 is consumed by the resistance element 202. As a result, the output signal W3 is waveform-formed so that the backswing of the amplitude is reduced, as shown by the solid line in FIG. 3B. Since the amplitude of the backswing in the output signal W3 is reduced, it is possible to prevent unintended conduction of the first switch 51 and the second switch 52.

As described above, in the non-contact power sensor device 1 according to the first embodiment, the switch drive unit 56 generates a positive electrode pulse signal and a negative electrode pulse signal, and the generated positive electrode pulse signal and negative electrode pulse signal are used to obtain a second. The first switch 51 and the second switch 52 are driven. Since it is not necessary to separately provide a switch drive unit for the measurement of the AC current and the measurement of the AC voltage, and the increase in the mounting volume of the circuit is suppressed by that amount, the non-contact power sensor device 1 can be miniaturized. ..

It should be noted that the combination of each embodiment, the modification of each arbitrary component of the embodiment, or the omission of any component in each of the embodiments is possible.

The non-contact power sensor device according to the present disclosure can be used, for example, for observing AC power supplied by a power distribution cable.

1 non-contact power sensor device, 2 voltage probe, 3 current probe, 5 sensor circuit, 6 cable, 6a cable conductor, 6b cable coating, 7 AC power supply, 41, 42 probe cable, 51 first switch, 52 second Switch, 53 capacitor element, 54 capacitor, 55 AD converter, 56 switch drive unit, 57 processing unit, 101, 102 diode element, 103, 104, 202 resistance element, 200 reset circuit, 201 third switch, resistance element 210 Transformer, 561 diode pulse buffer, 562 insulation circuit, 563 pulse separation circuit.

Claims

A voltage probe that observes the voltage generated in the measurement target in a non-contact state with the measurement target,
A current probe that observes the current flowing through the measurement target in a state of non-contact with the measurement target, and
A sensor circuit that calculates the power of the measurement target using each signal observed by the voltage probe and the current probe, and
With
The sensor circuit
The first switch used for observing the transient response of the voltage signal observed by the voltage probe,
A second switch used for observing the transient response of the current signal observed by the current probe,
The switch drive unit that drives the first switch and the second switch,
A processing unit that controls the drive of the first switch and the second switch by the switch drive unit,
Have,
The switch drive unit
A positive pulse signal having a positive amplitude and a negative pulse signal having a negative amplitude are generated according to a control signal output from the processing unit, and the generated positive pulse signal and negative pulse signal are used to generate the first pulse signal. A non-contact power sensor device comprising driving one switch and the second switch.
The switch drive unit
A pulse buffer capable of outputting bipolar pulse signals with amplitudes of positive and negative electrodes,
A pulse separation circuit that separates the bipolar pulse signal output from the pulse buffer into the positive electrode pulse signal and the negative electrode pulse signal.
An insulating circuit that outputs a pulse signal input from the pulse buffer to the pulse separation circuit in a state where the pulse buffer and the pulse separation circuit are insulated.
Have,
The pulse separation circuit
The non-contact power sensor device according to claim 1, wherein the positive electrode pulse signal is output to the first switch, and the negative electrode pulse signal is output to the second switch.
The insulation circuit
A transformer that outputs the bipolar pulse signal to the pulse separation circuit in a state where the pulse buffer and the pulse separation circuit are insulated.
A reset circuit that waveform-shapes the bipolar pulse signal output from the transformer, and
Have,
The reset circuit
A third switch that switches between inputting and blocking the bipolar pulse signal output from the pulse buffer to the reset circuit, and
A resistance element that consumes the counter electromotive force generated in the transformer, and
Have,
The processing unit
The second aspect of claim 2, wherein the bipolar pulse signal is input to the reset circuit by driving the third switch when the bipolar pulse signal output from the pulse buffer transitions to the off level. Non-contact power sensor device.