JPH1194881A - Ac current detector - Google Patents
Ac current detectorInfo
- Publication number
- JPH1194881A JPH1194881A JP27338497A JP27338497A JPH1194881A JP H1194881 A JPH1194881 A JP H1194881A JP 27338497 A JP27338497 A JP 27338497A JP 27338497 A JP27338497 A JP 27338497A JP H1194881 A JPH1194881 A JP H1194881A
- Authority
- JP
- Japan
- Prior art keywords
- current
- voltage
- output
- zct
- signal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Landscapes
- Measurement Of Current Or Voltage (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、カレントトランス
(CT)及び零相変流器(ZCT)を利用して、交流電
流の実効値を求める交流電流検出装置に関する。[0001] 1. Field of the Invention [0002] The present invention relates to an AC current detecting device for obtaining an effective value of an AC current using a current transformer (CT) and a zero-phase current transformer (ZCT).
【0002】[0002]
【従来の技術】従来の交流電流検出装置の機能ブロック
図の一例を図2に示す(図は出力形式が電流出力の場
合)。2. Description of the Related Art An example of a functional block diagram of a conventional AC current detecting apparatus is shown in FIG.
【0003】CT又はZCT1は、トランスの一種で、
1次側に流れている交流電流を2次側(1次−2次は電
気的に絶縁されている)に負荷抵抗9を接続することに
より、前記1次側電流電圧に変換して検出する製品であ
る。[0003] CT or ZCT1 is a type of transformer.
By connecting a load resistor 9 to the secondary side (primary and secondary are electrically insulated), the alternating current flowing to the primary side is converted into the primary side current and detected. Product.
【0004】前記負荷抵抗9の両端の電圧を増幅部2で
増幅し、ハイパスフィルタ10で直流成分を削除した後
に、全波整流11により、全整流を行い、ローパスフィ
ルタ12で平滑化(直流化)する。The voltage at both ends of the load resistor 9 is amplified by the amplifying unit 2, the DC component is removed by the high-pass filter 10, full rectification is performed by the full-wave rectifier 11, and smoothing (DC conversion) is performed by the low-pass filter 12. ).
【0005】平滑出力(VOUT1)は、一般式で下記のよ
うに表される。[0005] The smoothed output (VOUT1) is represented by the following general formula.
【0006】VOUT1=K1×I+α1 但し、K1:変換定数、α1:オフセット成分、I:1次
電流。VOUT1 = K1 × I + α1 where K1: conversion constant, α1: offset component, I: primary current.
【0007】CT又はZCT1の感度ばらつき、及び増
幅部2のばらつきにより、前記K1の値が違うため、そ
のばらつきの吸収用として、増幅度調整用の増幅部13
の機能を必要とする。又、オフセット成分α1も、ここ
までの機能ブロックの誤差が、全て加わっており、ある
一定値にするために、オフセット電圧調整14の機能を
必要とする。Since the value of K1 is different due to the variation in sensitivity of CT or ZCT1 and the variation in the amplification unit 2, the amplification unit 13 for amplifying the amplification degree is used to absorb the variation.
Needs the function of. Also, the offset component α1 has all the errors of the function blocks so far added, and requires the function of the offset voltage adjustment 14 to make it a certain value.
【0008】電圧出力の場合は、ここまでの機能ブロッ
クで充分であるが、電流出力の場合は、更に、電圧−電
流変換回路15を必要とする。In the case of voltage output, the function blocks described so far are sufficient, but in the case of current output, a voltage-current conversion circuit 15 is further required.
【0009】[0009]
【発明が解決しようとする課題】ところで、前記交流電
流検出装置では、交流電圧を直流電圧(又は直流電流)
に変換(平滑化)するために、全波整流11の後に、ロ
ーパスフィルタ12を使用しているが、その結果、かな
りの応答遅れが存在する。In the AC current detecting device, the AC voltage is converted to a DC voltage (or a DC current).
Although a low-pass filter 12 is used after the full-wave rectification 11 to convert (smooth) the signal into a signal, there is a considerable response delay.
【0010】特に、商用電源(50又は60Hz)のよ
うな低周波においては、応答遅れは、数百ms〜数秒と
なり、実用上、かなりの問題となる。In particular, at low frequencies such as a commercial power supply (50 or 60 Hz), the response delay is several hundred ms to several seconds, which is a considerable problem in practical use.
【0011】本発明の目的は、応答遅れの少ない、信頼
性の高い、安価な交流電流検出装置を提供することあ
る。An object of the present invention is to provide a highly reliable and inexpensive AC current detecting device with little response delay.
【0012】[0012]
【課題を解決するための手段】本発明の課題を解決する
ための手段は、下記の通りとなる。Means for solving the problems of the present invention are as follows.
【0013】本発明は、交流電流をCT又はZCTで検
出し、前記CT又はZCTからの出力により、前記交流
電流の実効値(Io)を直流電圧、又は直流電流に変換
して検出する交流電流検出装置において、CT又はZC
Tからの交流信号の一周期における最大値(VMAX orI
MAX)、及び最小値(VMIN orIMIN)を検出し、前記最
大値及び最小値の差を直流電圧、又は直流電流に変換し
て出力信号とする交流電流検出装置である。According to the present invention, an AC current is detected by CT or ZCT, and an effective value (Io) of the AC current is converted into a DC voltage or DC current based on an output from the CT or ZCT to detect the AC current. In the detection device, CT or ZC
The maximum value in one cycle of the AC signal from T (VMAX or I
MAX) and a minimum value (VMIN or IMIN), and converts the difference between the maximum value and the minimum value into a DC voltage or a DC current to output an output signal.
【0014】[0014]
【発明の実施の形態】本発明の交流電流検出装置につい
て、説明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS An alternating current detecting device according to the present invention will be described.
【0015】CT又はZCTの出力両端に負荷抵抗を接
続し、前記負荷抵抗の両端出力(交流信号)を増幅した
後に、前記増幅信号を交流信号の一周期ごとに分割し、
前記一周期における最大値(VMAX orIMAX)及び最小
値(VMIN orIMIN)を検出し、前記最大値及び最小値
の差を直流電圧、又は直流電流に変換して出力信号とす
ることにより、高速応答である交流電流検出装置を提供
することが可能となる。A load resistor is connected to both ends of the output of the CT or ZCT, and after amplifying the output (AC signal) at both ends of the load resistor, the amplified signal is divided for each period of the AC signal.
The maximum value (VMAX or IMAX) and the minimum value (VMIN or IMIN) in the one cycle are detected, and the difference between the maximum value and the minimum value is converted into a DC voltage or a DC current as an output signal, thereby providing a high-speed response. It is possible to provide a certain alternating current detection device.
【0016】[0016]
【実施例】以下、本発明の実施例を図面に基づいて説明
する。Embodiments of the present invention will be described below with reference to the drawings.
【0017】図1は、本発明に基づく交流電流検出装置
の機能ブロック図である。CT又はZCT1の出力両端
に負荷抵抗9を接続し、前記負荷抵抗9の両端出力を増
幅する(但し、CTやZCT1の感度ばらつき及び増幅
部2のばらつきにより、そのばらつきの吸収用として増
幅度調整機能を付加する)。FIG. 1 is a functional block diagram of an AC current detecting device according to the present invention. A load resistor 9 is connected to both ends of the output of the CT or ZCT 1 to amplify the output of both ends of the load resistor 9 (however, due to variations in the sensitivity of the CT or ZCT 1 and variations in the amplifying unit 2, the amplification degree is adjusted to absorb the variation). Function).
【0018】この増幅機能とは別に、ある一定の発振を
繰り返しているクロック発振器3があり、前記クロック
周波数をN倍して、それが前記増幅信号の交流成分一周
期となるように、N倍クロック4を設定する。In addition to this amplification function, there is a clock oscillator 3 which repeats a certain oscillation, and multiplies the clock frequency by N times so that it becomes one cycle of the AC component of the amplified signal. Clock 4 is set.
【0019】前記増幅信号の交流成分の一周期間隔で、
前記増幅部出力の最大値(VMAX)及び最小値(VMIN)
を、それぞれ最大値検出部5及び最小値検出部6で検出
し、演算部7により(最大値−最小値)の演算をして、
直流電圧又は直流電流の出力8とする。At one period interval of the AC component of the amplified signal,
Maximum value (VMAX) and minimum value (VMIN) of the output of the amplifying section
Are detected by the maximum value detection unit 5 and the minimum value detection unit 6, respectively, and the calculation unit 7 calculates (maximum value−minimum value).
The output 8 is a DC voltage or DC current.
【0020】従来のブロックで存在していたローパスフ
ィルタもなくなり、低周波フィルタで必要となる大容量
コンデンサや高抵抗を必要としないため(50 or 60
Hz等の電力線では、特にカットオフ周波数の低いフィ
ルタが必要であった)、耐ノイズ性や信頼性の向上を図
ることができる。The low-pass filter existing in the conventional block is also eliminated, and the large-capacity capacitor and the high resistance required for the low-frequency filter are not required (50 or 60).
In the case of a power line such as a Hz, a filter having a particularly low cut-off frequency is required), and noise resistance and reliability can be improved.
【0021】[0021]
【発明の効果】以上、説明したように、交流電流をCT
又はZCTで検出し、前記CT又はZCTからの出力に
より、前記交流電流の実効値(I0)を直流電圧又は直
流電流に変換して検出する交流電流検出装置において、
CT又はZCTからの交流信号の一周期における最大値
(VMAX orIMAX)及び最小値(VMIN orIMIN)を検出
し、前記最大値及び最小値の差を直流電圧、又は直流電
流に変換して出力信号とすることにより、高速応答であ
る交流電流検出装置を提供することが可能となる。As described above, as described above, the alternating current is applied to the CT.
Or an AC current detection device that detects by ZCT and converts the effective value (I0) of the AC current into a DC voltage or a DC current based on the output from the CT or the ZCT,
The maximum value (VMAX or IMAX) and the minimum value (VMIN or IMIN) in one cycle of the AC signal from the CT or ZCT are detected, and the difference between the maximum value and the minimum value is converted into a DC voltage or DC current, and the output signal and By doing so, it is possible to provide an AC current detection device that has a high-speed response.
【図1】本発明の交流電流検出装置の機能ブロック図。FIG. 1 is a functional block diagram of an AC current detection device according to the present invention.
【図2】従来の交流電流検出装置の機能ブロック図。FIG. 2 is a functional block diagram of a conventional alternating current detection device.
1 CT又はZCT 2 増幅部 3 クロック発振器 4 N倍クロック 5 最大値検出部 6 最小値検出部 7 演算部 8 出力 8a 定電流出力 8b 定電圧出力 9 負荷抵抗 10 ハイパスフィルタ 11 全波整流 12 ローパスフィルタ 13 増幅度調整用の増幅部 14 オフセット電圧調整 15 電圧−電流変換回路 DESCRIPTION OF SYMBOLS 1 CT or ZCT 2 Amplification part 3 Clock oscillator 4 N times clock 5 Maximum value detection part 6 Minimum value detection part 7 Operation part 8 Output 8a Constant current output 8b Constant voltage output 9 Load resistance 10 High-pass filter 11 Full-wave rectification 12 Low-pass filter 13 Amplification part for amplification degree adjustment 14 Offset voltage adjustment 15 Voltage-current conversion circuit
Claims (1)
流器で検出し、前記カレントトランス及び零相変流器か
らの出力により、前記交流電流の実効値を直流電圧、又
は直流電流に変換して検出する交流電流検出装置におい
て、カレントトランス及び零相変流器からの交流信号の
一周期における最大値、及び最小値を検出し、前記最大
値及び最小値の差を直流電圧、又は直流電流に変換して
出力信号とすることを特徴とする交流電流検出装置。An AC current is detected by a current transformer or a zero-phase current transformer, and an effective value of the AC current is converted into a DC voltage or a DC current by an output from the current transformer and a zero-phase current transformer. In the AC current detection device, the maximum value and the minimum value in one cycle of the AC signal from the current transformer and the zero-phase current transformer are detected, and the difference between the maximum value and the minimum value is detected as a DC voltage or a DC current. An alternating current detection device characterized by converting the signal into an output signal.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP27338497A JPH1194881A (en) | 1997-09-19 | 1997-09-19 | Ac current detector |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP27338497A JPH1194881A (en) | 1997-09-19 | 1997-09-19 | Ac current detector |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH1194881A true JPH1194881A (en) | 1999-04-09 |
Family
ID=17527153
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP27338497A Withdrawn JPH1194881A (en) | 1997-09-19 | 1997-09-19 | Ac current detector |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH1194881A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102914683A (en) * | 2012-11-01 | 2013-02-06 | 天津市电力公司 | Method for acquiring single-phase grounding current of three-phase single cable |
JP2014169952A (en) * | 2013-03-05 | 2014-09-18 | Ricoh Co Ltd | Electric current sensor, and electric power sensor |
CN107942126A (en) * | 2018-01-15 | 2018-04-20 | 广东美的暖通设备有限公司 | Current detection circuit, method, readable storage medium storing program for executing and power electronic equipment |
-
1997
- 1997-09-19 JP JP27338497A patent/JPH1194881A/en not_active Withdrawn
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102914683A (en) * | 2012-11-01 | 2013-02-06 | 天津市电力公司 | Method for acquiring single-phase grounding current of three-phase single cable |
JP2014169952A (en) * | 2013-03-05 | 2014-09-18 | Ricoh Co Ltd | Electric current sensor, and electric power sensor |
CN107942126A (en) * | 2018-01-15 | 2018-04-20 | 广东美的暖通设备有限公司 | Current detection circuit, method, readable storage medium storing program for executing and power electronic equipment |
CN107942126B (en) * | 2018-01-15 | 2020-03-06 | 广东美的暖通设备有限公司 | Current detection circuit, method, readable storage medium and power electronic device |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
A761 | Written withdrawal of application |
Effective date: 20041108 Free format text: JAPANESE INTERMEDIATE CODE: A761 |