WO1999041618A1 - Instrument for measuring alternating current - Google Patents

Instrument for measuring alternating current Download PDF

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Publication number
WO1999041618A1
WO1999041618A1 PCT/JP1999/000565 JP9900565W WO9941618A1 WO 1999041618 A1 WO1999041618 A1 WO 1999041618A1 JP 9900565 W JP9900565 W JP 9900565W WO 9941618 A1 WO9941618 A1 WO 9941618A1
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WO
WIPO (PCT)
Prior art keywords
current
voltage
charging
circuit
discharging
Prior art date
Application number
PCT/JP1999/000565
Other languages
French (fr)
Japanese (ja)
Inventor
Shigenori Torihata
Original Assignee
Furukawa Electric Co., Ltd.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Furukawa Electric Co., Ltd. filed Critical Furukawa Electric Co., Ltd.
Priority to GB9924047A priority Critical patent/GB2339295A/en
Publication of WO1999041618A1 publication Critical patent/WO1999041618A1/en

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/22—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using conversion of ac into dc
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
    • G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
    • G01R15/18—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers
    • G01R15/183—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers using transformers with a magnetic core
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
    • G01R19/252—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques using analogue/digital converters of the type with conversion of voltage or current into frequency and measuring of this frequency

Definitions

  • the present invention relates to an AC current measuring device, and more particularly to an AC current measuring device used for current measurement requiring high insulation, such as when measuring an AC current flowing at a high voltage.
  • FIG. 11 is a circuit diagram showing a conventional AC current measuring device. As shown in FIG. 11, a conductor 52 penetrates through a transformer 51, and the transformer 51 is excited by a primary AC current flowing through the conductor 52.
  • a diode 54 is connected to the coil 53 on the secondary side of the transformer 51.
  • Diode 54 performs half-wave rectification of a secondary current generated in coil 53 on the secondary side of transformer 51 by a primary alternating current flowing through conductor 52.
  • a capacitor 55 for charging the current rectified by the diode 54 is connected to the cathode of the diode 54.
  • a zener diode 56 through which a current flows when the charging voltage of the capacitor 55 becomes higher than a constant voltage is connected to the force source of the capacitor 55 and the diode 54.
  • the light emitting diode 59 is connected to the cathode of the diode diode 56 via a coil 57 and a resistor 58.
  • the light emitting diode 59 is connected to a thyristor 60 that is turned on when the current flows through the Zener diode 56 to discharge the capacitor 55 when the charging voltage of the capacitor 55 becomes higher than the constant voltage.
  • the gate of the thyristor 60 is connected between the anode of the diode diode 56 and the resistor 61.
  • the discharge current of the capacitor 55 flows excessively through the coil 57 and charges the capacitor 55 in the reverse direction.
  • a reverse voltage is applied to the thyristor 60, the thyristor 60 is turned off.
  • the charging of the capacitor 55 is newly started, and when a predetermined charging voltage is reached, the light emitting diode 59 emits light again, and then the thyristor 60 is turned off.
  • the light emitting diode 59 emits light (flashes) intermittently and generates a pulse.
  • the frequency of the generated pulse is determined by the charging speed of the capacitor 55, and the charging speed is determined by the voltage induced in the coil 53, that is, the current flowing through the conductor 52.
  • the secondary current generated by the transformer 51 causes the light-emitting diode 59 to emit light, so that it is not necessary to supply operating power from the outside, and insulation from the outside world is maintained. Easy.
  • the charging / discharging time of the capacitor 55 is determined by the capacitance of the capacitor 55, and this capacitance also has large variations among elements, and the effect of a temperature change cannot be ignored.
  • a capacitor 55 having a relatively large capacitance is required, but in general, the larger the capacitance 55, the more the variation and temperature characteristics of each element. The change is large.
  • An object of the present invention is to provide an AC current measurement device capable of performing high-precision current measurement without being affected by variations in elements and temperature characteristics by separating a power supply function and a current measurement function. Is to do.
  • an AC current measuring apparatus includes a transformer for generating a secondary current on a secondary side by a primary AC current flowing on a primary side, and a secondary current generated by the transformer.
  • Charging / discharging control means for controlling to discharge when the value is higher than the value, load resistance provided in the circuit through which the secondary current flows, and discharging current from the charging / discharging means is supplied for operating power and generated by the load resistance Voltage-frequency conversion means for converting a voltage value to a frequency value, and transmission means for supplying a discharge current from the charging / discharging means for operating power and transmitting a measurement signal output from the voltage-frequency conversion means to the outside.
  • the power procurement function and the current measurement function are separated, and the voltage frequency conversion means is used as the current measurement function, and the discharge current from the charging / discharging means is used only for the operating power of the voltage frequency conversion means. Since it is used, it is not affected by the variation of the element and the temperature characteristic.
  • the charge / discharge control means includes: a zener diode in which a current flows when the voltage generated by the secondary current becomes higher than a predetermined value; and a voltage generated by the secondary current when a current flows in the zener diode.
  • the thyristor includes a thyristor that reduces the current to a saturation voltage, and a backflow prevention diode that prevents the discharge current from the charging / discharging means from flowing back into the thyristor. In this case, even when the voltage induced by the secondary current is large, the thyristor turns on and the voltage drops to the saturation voltage of the thyristor, so that the power consumption of the entire processing circuit can be reduced.
  • the rectifier may be one that performs full-wave rectification on the secondary current or one that performs half-wave rectification on the secondary current.
  • FIG. 1 is a circuit diagram showing an AC current measuring device according to a first embodiment of the present invention.
  • 2 (A) is a waveform diagram of a primary alternating current, (B) shows a waveform of the secondary current i 2, (C) is a waveform diagram of the voltage 1 ⁇ 4, (D) is a waveform diagram of the voltage V 2.
  • A is a waveform diagram of the voltage V 3
  • B shows a waveform of the voltage V 4
  • C the voltage V 5.
  • FIG. 4 is a circuit diagram showing an AC current measuring device according to a second embodiment of the present invention.
  • 5 (A) is a waveform diagram of the primary alternating current, (B) is a waveform diagram of the secondary current i 2 , (C) is a waveform diagram of the voltage V, and (D) is a waveform diagram of the voltage V 2 .
  • FIG. 6 is a circuit diagram showing an AC current measuring device according to a third embodiment of the present invention.
  • 7A is a waveform diagram of the primary alternating current
  • FIG. 7B is a waveform diagram of the voltage V
  • Figure 8 is a waveform diagram of the voltage V 3 in the first embodiment.
  • FIG. 9 is a circuit diagram showing an AC current measuring device according to a fourth embodiment of the present invention.
  • Figure 10 (A) shows a waveform of the voltage V 6, (B) shows a waveform of the voltage V 2, (C) shows a waveform of the voltage V 3, (D) shows a waveform of the voltage V 4, (E) is it is a waveform diagram of the voltage V 5.
  • FIG. 11 is a circuit diagram showing a conventional AC current measuring device. BEST MODE FOR CARRYING OUT THE INVENTION
  • FIG. 1 is a circuit diagram showing an AC current measuring device according to a first embodiment of the present invention.
  • a rectifier circuit 4 is connected to the secondary coil 3 of the transformer 1.
  • the rectifier circuit 4 is a bridge circuit composed of four diodes, and a secondary current generated in the secondary coil 3 of the transformer 1 by a primary alternating current i flowing through the conductor 2. i 2 is full-wave rectified.
  • the rectifier circuit 4 is connected to a capacitor 6 for charging a secondary current i 2 via a diode 5 for preventing reverse current (forward voltage V f ).
  • a current flows between the rectifier circuit 4 and the anode of the diode 5 when a charging voltage of the capacitor 6 becomes higher than a constant voltage, and a current flows through the diode 7 and the diode 7.
  • thyristor 8 to decrease the voltage V, which is generated by the secondary current i 2 is turned oN when the flow to the saturation voltage V s is connected in parallel.
  • the gate of thyristor 8 is connected between the anode of zener diode 7 and resistor 9.
  • the capacitors of the capacitor 6 and the diode 5 are connected to a voltage / frequency conversion circuit 10 (hereinafter referred to as a V / F conversion circuit) via a power procurement path K for procuring power required for current measurement. ) And an electrical / optical conversion circuit 11 (hereinafter referred to as an E / 0 conversion circuit).
  • a voltage / frequency conversion circuit 10 hereinafter referred to as a V / F conversion circuit
  • an electrical / optical conversion circuit 11 hereinafter referred to as an E / 0 conversion circuit.
  • V / F conversion circuit 10 it is preferable to use, for example, VFC62B manufactured by Burr Brown Inc. in the United States. This device can achieve an accuracy of 0.004% non-linearity in the range of 20 ° C to 70 ° C, which is extremely difficult to achieve with a combination of individual elements.
  • the E / 0 conversion circuit 11 a light emitting diode may be used.
  • a current measurement path K 2 for sending a current measurement signal to the F conversion circuit 10 (shown by a dotted line to distinguish it from ⁇ ) Is provided.
  • One end of the current measurement path K 2 is connected between the rectifying circuit 4 and the load resistor 12, the other end is connected to the V / converter 10.
  • One end of the load resistor 12, the resistor 9, the capacitor 6, and the cathode of the thyristor 8 are grounded.
  • the ⁇ / 0 conversion circuit 11 is connected via an optical fiber 13 to an optical / electrical conversion unit 14 (hereinafter referred to as ⁇ conversion unit) of a signal transmission destination, and the 0 / ⁇ conversion unit 14 includes a frequency / voltage conversion unit 15
  • FZV converter (Hereinafter referred to as FZV converter).
  • a first alternating current i for example, 50 Hz or 60 Hz
  • a waveform as shown in FIG. 2 ( ⁇ ) is flowing through the conductor 2 to be measured.
  • the secondary current i 2 flows through the rectifier circuit 4 and the diode 5 to the capacitor 6 and is charged.
  • the discharge current of the capacitor 6 flows to the V / F conversion circuit 10 and the E / 0 conversion circuit 11 via the power procurement path. Therefore, it is possible to supply operating power to the VZF conversion circuit 10 and the EZO conversion circuit 11 internally.
  • the voltage V at the cathode of the diode diode 7! The waveform of is shown in Fig. 2 (C).
  • the constant voltage V TM of Wwena one Daio one door, the voltage V 3 to the subsequent circuit (VZF converter 10 and EZO conversion circuit 11) requires, the forward voltage V, only large value of Daio one de 5 Is set to.
  • V TH may be set to 5.7 V.
  • V TH may be set to 5.7 V.
  • the primary AC current i is large and the voltage induced by the secondary current i 2 is large, the thyristor 8 turns ON and V! Voltage drops to Vs, which is the saturation voltage of thyristor 8.
  • the power consumption of the processing circuit overall is reduced (saturation voltage V s of the thyristor 8, if the power consumption of When 1.5V circuits is about 1.5 W), heat generation due to the secondary current i 2 Can be reduced.
  • the transformer 1 does not pass a direct current, the secondary current i 2 always becomes 0 at regular intervals.
  • thyristor 8 must be turned off and repeat the same operation as the previous cycle. (See Fig. 2 (C)). For example, when the secondary current i 2 is a sine wave of 50 Hz, the same operation is repeated every 10 msec. Considering this operation, it can be seen that the capacity of the capacitor 6 connected to the cathode side of the diode 5 should be set to a value that can cover the current consumption by the subsequent processing circuit for only 10 msec.
  • the diode 5 prevents the charge accumulated in the capacitor 6 from flowing back to the thyristor 8 at the ON time.
  • the transformer 1 acts as a constant current source as long as the load resistance 12 is not extremely large. Therefore, the transformer 1 generates the secondary current i 2 which is a constant current regardless of the variation of the forward voltage of the diode of the rectifier circuit 4 and the variation of the saturation voltage Vs when the thyristor 8 is turned on, and the change due to the temperature characteristic. It has a function to adjust its own generated voltage so that it flows. Therefore, a secondary current i 2 that accurately reflects the current flowing through the conductor 2 and the number of windings N flows through the load resistor 12.
  • the rectifier circuit 4 since the rectifier circuit 4 performs full-wave rectification, a current i 2 having a full-wave rectified waveform flows through the load resistor 12 as shown in FIG. 2B.
  • This secondary current i 2 generates a voltage V 2 having a waveform as shown in FIG. 2 (D) due to the load resistance 12 (in FIG. 2 (D), the reference potential becomes negative as shown in FIG. 1). .
  • This voltage V 2 is converted into a pulse train frequency by a VZF conversion circuit 10 provided at one end of the current measurement path K 2 , as shown in FIG.
  • the converted frequency measurement signal is converted into an optical signal by the ⁇ / 0 conversion circuit 11, and the optical signal is transmitted to a remote place insulated by the optical fiber 13.
  • Transmitted optical signal by ⁇ varying section 14 and F / V converter 15 is demodulated into demodulated voltage V 5 shown in Figure 3 (C).
  • the current flowing through the conductor 2 can be measured at the insulated observation site.
  • the thyristor 8 and the antenna diode 7 are arranged before the capacitor 6 and the load resistor 12 for measuring the current is provided.
  • Current measurement and power procurement can be performed at the same time, and the capacitor 6 that performed the two functions of power procurement and current measurement in the conventional technology is used only for power procurement, and not used for current measurement. As a result, it is not affected by the variation of the element and the temperature characteristic. Therefore, the variation in characteristics between products is suppressed High-precision current measurement is possible in the range.
  • the thyristor 8 is used for the power procurement function, power that is not required by the subsequent processing circuit is not taken in except for the minimum power, so that heat generation can be suppressed. Thereby, a wide current measurement range can be obtained.
  • the primary alternating current is rather large, even if a large secondary current i 2, heating is small, effective at high current side of the secondary current i 2.
  • a diode 20 is used to half-wave rectify the secondary current i 2 . Therefore, when the primary alternating current i, as shown in FIG. 5 (A), flows, the current i 2 having a half-wave rectified waveform flows through the load resistance 12, as shown in FIG. 5 (B). And Further, the voltage V of the force source of the Zener diode 7 and the voltage V 2 between the coil 3 and the load resistor 12 have waveforms as shown in FIGS. 5 (C) and 5 (D), respectively.
  • a third embodiment of the present invention will be described.
  • a zenither having a constant voltage of 5.7 V is used without using a thyristor 8.
  • Diode 30 is used. Therefore, when the primary alternating current i, as shown in FIG. 7 (A), flows, the voltage V, of the power source of the zener diode 7, becomes as shown in FIG. become.
  • the thyristor 8 is not used unlike the first embodiment, the number of parts can be reduced, and the structure can be simplified.
  • the alternating current measuring device when the primary AC current i, is sufficiently large, the voltage V 3 becomes I UNA waveform shown in FIG. 3 (A), the voltage V D, V / F converter The output voltage V 4 shown in FIG. 3 (B) is obtained because the operation exceeds the operation guarantee voltage of the circuit 10 and the EZO conversion circuit 11 and operates stably.
  • V D decreases as the primary alternating current decreases, and as shown in FIG. 8, when the voltage V 3 falls below the operation guarantee voltage V K of the circuit, the operation of the circuit stops. Therefore, in the first embodiment, the lower limit (i lmin ) of the operating current is determined, and it becomes impossible to measure the lower limit of the operating current in .
  • the fourth embodiment is characterized in that when the voltage drops to a predetermined voltage, the power supply to the VZF conversion circuit 10 and the EZO conversion circuit 11 is positively cut off.
  • FIG. 9 is a circuit diagram showing an AC current measuring device according to a fourth embodiment of the present invention.
  • the AC current measurement device according to the fourth embodiment is provided with a circuit operation switching unit 40 added to the first embodiment.
  • the circuit operation switching section 40 includes a circuit diode 41 for setting a circuit operation start voltage, a PNP-type transistor 42 for switching ON / OFF of the circuit operation, and a thyristor for controlling the transistor 42. 43, a circuit diode for stopping the circuit operation, a voltage setting diode 44, and resistors 45 and 46.
  • the emitter of the transistor 42 is connected to the cathode of a circuit diode 41 for setting the circuit operation start voltage, the base is connected to the anode of the thyristor 43, and the collector is connected to the V node. Connected to F conversion circuit 10 and E / 0 conversion circuit 11.
  • the gate of the thyristor 43 is connected between the circuit diode 41 for setting the circuit operation start voltage and the resistor 45, and its cathode is connected to the cathode of the circuit diode 44 for setting the circuit operation stop voltage. Connected to.
  • the operation of the fourth embodiment will be described.
  • the voltage V 3 becomes the value of V C0NT by the constant voltage set by the ninina diode 7.
  • the setting voltage V 0N of the circuit diode 41 for setting the circuit operation start voltage is smaller than the setting voltage V C0NT of the zener diode 7, so that the circuit is always turned on.
  • the thyristor 43 for transistor control is turned on and the transistor 42 is turned on, so that the V / F conversion circuit 10 and E
  • This voltage V 3 is the set voltage V of the zener diode 41 for setting the circuit operation start voltage.
  • the transistor 42 When n is exceeded, the transistor 42 is turned on, and power is supplied to the subsequent stage V / F conversion circuit 10 and E / 0 conversion circuit 11 to start operation.
  • VON> VOFF the circuit will have a hysteresis characteristic
  • a predetermined time is operation subsequent circuit leading to V 0FF from V 0N, the other times, these subsequent circuit operation
  • the operation stops, and electric charge is accumulated in the capacitor 6.
  • the voltage V 6 on the collector side of the transistor 42 changes as shown in FIG.
  • V 0FF is set to be equal to or higher than the operation guarantee voltage V K of the circuit, the processing circuit at the subsequent stage can be reliably operated during the period from V 0N ⁇ V 0FF .
  • Voltage V 2 the voltage V 3, the voltage V 4 and the voltage V 5 are as shown in FIGS 10 (B) ⁇ FIG 10 (E).
  • Voltage V 2 generated at both ends of the load resistor 12, as shown in FIG. 10 (B), the same as the first embodiment.
  • the VZF conversion circuit 10 and the ⁇ conversion circuit 11 operate only during the period of V 0N ⁇ V 0FF , so that the output voltage V 4 of the V / F conversion circuit 10 is Only the period is obtained, as shown in Figure 10 (D).
  • transmission destination of the output voltage (demodulated voltage) V 5 becomes the solid line portion in FIG. 10 (E). Note that the broken line from the solid line shown in Fig. 10 (E) can be interpolated by estimation.
  • N the set voltage V 0FF circuit operation stop voltage setting Tsu zener diode 44, VCONT>VON> With VOFF, performs a continuous operation for a period of V 3> V ON, V 0N > V 3> V 0FF Intermittent operation is performed during the falling period of V 0FF
  • current measurement can be performed even when the next current is low, and the circuit operation stop voltage V 0FF is set higher than the circuit operation assurance voltage V K. It can avoid unstable operation of the circuit in the circuit operation guarantee voltage V K vicinity.
  • the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the technical matters described in the claims.
  • the power conversion circuit 11 can be replaced with a wireless transmission device as disclosed in, for example, US Pat. No. 4,384,289.
  • the rectifier circuit 4 in the third and fourth embodiments may be replaced with one diode, and the secondary current i 2 may be half-wave rectified.

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  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Current Or Voltage (AREA)

Abstract

An instrument for measuring alternating current comprises a transformer (1) for producing secondary current on its secondary side from primary current on its primary side, a rectifier circuit (4) for rectifying the secondary current derived from the transformer (1), a capacitor (6) for receiving the rectified current from the rectifier (4), a Zener diode (7) for controlling to charge the capacitor (6) with the secondary current to a predetermined voltage and discharge it at the predetermined voltage, a load resistor (12) provided in a circuit where the secondary current flows, a voltage-to-frequency converter (10) supplied with the secondary current from the capacitor (6) for converting the voltage across the load resistor (12) to a frequency, and an optical fiber (13) and an electric-to-light converter (11) supplied with the discharge current from the capacitor (6) for transmitting signals output from the voltage-to-frequency converter (10) through the fiber.

Description

明 細 書 交流電流計測装置 技術分野  Description AC current measuring device Technical field
本発明は、 交流電流計測装置に関し、 特に、 高電圧で流れている交流電流を計 測する場合のように、 高い絶縁性が要求される電流計測のために用いられる交流 電流計測装置に関する。 背景技術  The present invention relates to an AC current measuring device, and more particularly to an AC current measuring device used for current measurement requiring high insulation, such as when measuring an AC current flowing at a high voltage. Background art
一般に、 受配電設備における配電線、 発電設備における送電線、 工場等の大電 力を要する負荷等高電圧で流れている交流電流を計測する場合、 高い絶縁性が要 求される。 このような場合、 例えば、 特開昭 56— 63264号公報に開示されている ように、 電流を光信号に変換して検出する交流電流計測装置が用いられる。  Generally, when measuring alternating current flowing at high voltage, such as distribution lines in power receiving and distribution facilities, transmission lines in power generation facilities, and loads requiring large power in factories, etc., high insulation properties are required. In such a case, for example, as disclosed in Japanese Patent Application Laid-Open No. 56-63264, an alternating current measuring device that converts a current into an optical signal and detects it is used.
図 11は、 従来の交流電流計測装置を示す回路図である。 図 11に示すように、 変 成器 51内に導体 52が貫通しており、 導体 52に流れる一次交流電流によって変成 器 51が励磁される。  FIG. 11 is a circuit diagram showing a conventional AC current measuring device. As shown in FIG. 11, a conductor 52 penetrates through a transformer 51, and the transformer 51 is excited by a primary AC current flowing through the conductor 52.
変成器 51の二次側のコイル 53にはダイォ—ド 54が接続される。 ダイォ一ド 54 は、 導体 52に流れる一次交流電流によつて変成器 51の二次側のコイル 53に発生 する二次電流を半波整流する。 ダイオード 54のカソ一ドにはダイォード 54によつ て整流された電流を充電するコンデンサ 55が接続される。  A diode 54 is connected to the coil 53 on the secondary side of the transformer 51. Diode 54 performs half-wave rectification of a secondary current generated in coil 53 on the secondary side of transformer 51 by a primary alternating current flowing through conductor 52. A capacitor 55 for charging the current rectified by the diode 54 is connected to the cathode of the diode 54.
コンデンサ 55及びダイォ一ド 54の力ソードにはコンデンサ 55の充電電圧が定 電圧よりも高くなると電流が流れるツエナ一ダイォード 56が接続される。 ッヱナ一 ダイォ一ド 56のカソ一ドにはコイル 57及び抵抗 58を介して発光ダイォ一ド 59力 接続される。 発光ダイオード 59にはコンデンサ 55の充電電圧が定電圧よりも高く なり、 ツエナ一ダイォ一ド 56に電流が流れると ONしてコンデンサ 55を放電させ るサイリスタ 60が接続される。 サイリスタ 60のゲ一トはッヱナ一ダイォ一ド 56 のァノ一ドと抵抗 61との間に接続される。  A zener diode 56 through which a current flows when the charging voltage of the capacitor 55 becomes higher than a constant voltage is connected to the force source of the capacitor 55 and the diode 54. The light emitting diode 59 is connected to the cathode of the diode diode 56 via a coil 57 and a resistor 58. The light emitting diode 59 is connected to a thyristor 60 that is turned on when the current flows through the Zener diode 56 to discharge the capacitor 55 when the charging voltage of the capacitor 55 becomes higher than the constant voltage. The gate of the thyristor 60 is connected between the anode of the diode diode 56 and the resistor 61.
次に、 従来の交流電流計測装置の動作を説明する。 測定対象となる導体 52に一 次交流電流が流れると、 変成器 51に巻かれたコイル 53に電圧が生じ、二次電流が 流れるようになる。 この二次電流は、 ダイオード 54によって半波整流され、 コン デンサ 55に充電される。 この時、 ツエナーダイオード 56及びサイリスタ 60はォ フになっているので、 コンデンサ 55は放電されない。 Next, the operation of the conventional AC current measuring device will be described. One conductor 52 to be measured When the secondary AC current flows, a voltage is generated in the coil 53 wound around the transformer 51, and a secondary current flows. This secondary current is half-wave rectified by the diode 54, and is charged in the capacitor 55. At this time, since the Zener diode 56 and the thyristor 60 are off, the capacitor 55 is not discharged.
コンデンサ 55の充電電圧が徐々に昇圧してゆき、 ッヱナ一ダイオード 56の定電 圧よりも高くなると、 ッヱナ一ダイォ一ド 56に電流が流れ、抵抗 61を介してサイ リスタ 60のゲ一卜に電圧が印可される。 これによつて、 サイリスタ 60がオンし、 コンデンサ 55に蓄積された電流が放電し、 コイル 57、 抵抗 58を介して発光ダイ ォ一ド 59に流れ、 発光ダイォ一ド 59がパルス状に発光する。  When the charging voltage of the capacitor 55 gradually increases and becomes higher than the constant voltage of the zener diode 56, a current flows through the zener diode 56, and the current flows to the gate of the thyristor 60 via the resistor 61. Voltage is applied. As a result, the thyristor 60 is turned on, the current stored in the capacitor 55 is discharged, flows through the coil 57 and the resistor 58, flows into the light emitting diode 59, and the light emitting diode 59 emits light in pulses. .
コンデンサ 55の放電電流は、 コイル 57により流れ過ぎてコンデンサ 55を逆方 向に充電し、 サイリスタ 60に逆電圧が印可されると、 サイリスタ 60がオフになる。 サイリスタ 60がオフになると、 コンデンサ 55の充電が新たに開始し、 所定の充 電電圧に達すると、再度発光ダイォ一ド 59力発光し、 その後サイリスタ 60がオフ する。  The discharge current of the capacitor 55 flows excessively through the coil 57 and charges the capacitor 55 in the reverse direction. When a reverse voltage is applied to the thyristor 60, the thyristor 60 is turned off. When the thyristor 60 is turned off, the charging of the capacitor 55 is newly started, and when a predetermined charging voltage is reached, the light emitting diode 59 emits light again, and then the thyristor 60 is turned off.
このような繰り返しにより発光ダイオード 59は間欠的に発光 （点滅） し、 パル スを発生させる。 発生したパルスの周波数はコンデンサ 55の充電速度で決定され、 その充電速度はコイル 53に誘起される電圧すなわち導体 52を流れる電流によって 決定される。  Due to such repetition, the light emitting diode 59 emits light (flashes) intermittently and generates a pulse. The frequency of the generated pulse is determined by the charging speed of the capacitor 55, and the charging speed is determined by the voltage induced in the coil 53, that is, the current flowing through the conductor 52.
従って、発光ダイォ—ド 59から発生する光信号を光ファイバ一 70によって観測 地まで伝送し、 発光パルスの周波数を計測することにより、 絶縁された観測地で 導体 52に流れる電流を計測することができる。  Therefore, by transmitting the optical signal generated from the light emitting diode 59 to the observation site through the optical fiber 170 and measuring the frequency of the light emission pulse, it is possible to measure the current flowing through the conductor 52 at the isolated observation site. it can.
従来の交流電流計測装置によれば、 変成器 51によって生成される二次電流によ つて発光ダイォ一ド 59を発光させるため、 外部から動作電力を供給する必要がな く、 外界との絶縁が容易である。  According to the conventional AC current measuring device, the secondary current generated by the transformer 51 causes the light-emitting diode 59 to emit light, so that it is not necessary to supply operating power from the outside, and insulation from the outside world is maintained. Easy.
し力、し、従来の交流電流計測装置では、 たとえ、 サイリスタ 60が ONしても、 サ ィリスタ 60の ON時の飽和電圧 Vsと発光ダイォ一ド 59の順電圧 Vfが生じるので、 コンデンサ 55は完全には短絡されない。 そのため、 サイリスタ 60の ON時にも一 定の電荷がコンデンサ 55に残り、 次回の充電時間を短くするという悪影響を及ぼ す。 なお、 コイル 57を用い、 コンデンサ 55を逆方向に充電しているが、 これはサイ リスタ 60を有効に OFFするためのものであり、精度向上には全く寄与しておらず、 逆充電量もこれらの Vs及び Vf による影響を受けてしまう。 And power, and, in the conventional alternating current measurement apparatus, even if the thyristor 60 is ON, since the forward voltage V f of the saturation voltage V s of ON time of service Irisuta 60 emitting Daio one de 59 occurs, capacitor 55 is not completely short-circuited. Therefore, even when the thyristor 60 is turned on, a certain amount of electric charge remains in the capacitor 55, which has the adverse effect of shortening the next charging time. The capacitor 55 is charged in the reverse direction using the coil 57, but this is for turning off the thyristor 60 effectively, and does not contribute to improving the accuracy at all. It would be affected by these V s and V f.
また、 このサイリスタ 60の飽和電圧 Vsと発光ダイォ一ド 59の順電圧 Vfが一定 ならば、 この効果を打ち消すことも可能であるが、 素子のバラツキや温度特性に よる変化があるため、 実際には困難である。 Further, if a constant forward voltage Vf of the saturation voltage V s and the light emitting Daio one de 59 of the thyristor 60, although it is possible to counteract this effect, there is a change due to the variation and temperature characteristics of the device, the actual Is difficult.
さらに、 コンデンサ 55の充放電時間は、 コンデンサ 55の静電容量によって決ま るが、 この静電容量も素子毎のバラツキが大きく、 また、 温度変化による影響も 無視できない。 特に、 発光ダイォ一ド 59を充分に発光させるためには、 ある程度 静電容量の大きなコンデンサ 55を必要とするが、 通常、 静電容量の大きなコンデ ンサ 55ほど、 素子毎のバラツキ及び温度特性の変化が大きい。  Furthermore, the charging / discharging time of the capacitor 55 is determined by the capacitance of the capacitor 55, and this capacitance also has large variations among elements, and the effect of a temperature change cannot be ignored. In particular, in order for the light emitting diode 59 to emit light sufficiently, a capacitor 55 having a relatively large capacitance is required, but in general, the larger the capacitance 55, the more the variation and temperature characteristics of each element. The change is large.
従って、 従来の交流電流計測装置では、 電力調達機能と電流計測機能とを一緒 の素子で行っていたので、 装置毎のバラツキが大きく、 また温度による影響を受 けやすいため、 高精度な電流計測を行うことができなかった。 発明の開示  Therefore, in the conventional AC current measurement device, the power procurement function and the current measurement function are performed by the same element, and the variation between devices is large and the device is easily affected by temperature. Could not do. Disclosure of the invention
本発明の目的は、 電力調達機能と電流計測機能とを分離することにより、 素子 のバラツキや温度特性による影響を受けることなく、 高精度な電流計測を行うこ とができる交流電流計測装置を提供することにある。  An object of the present invention is to provide an AC current measurement device capable of performing high-precision current measurement without being affected by variations in elements and temperature characteristics by separating a power supply function and a current measurement function. Is to do.
上述した目的を達成するため、 本発明の交流電流計測装置は、 一次側に流れて いる一次交流電流によって二次側に二次電流を発生させる変成器と、 その変成器 で発生した二次電流を整流する整流手段と、 その整流手段で整流された電流を充 電及び放電する充放電手段と、 その充放電手段を、 二次電流で生成される電圧が 所定値になるまで充電させ、 所定値より高くなると放電するように制御する充放 電制御手段と、 二次電流が流れる回路に設けられる負荷抵抗と、 充放電手段から の放電電流が動作電力用に供給され、 負荷抵抗で発生する電圧値を、 周波数値に 変換する電圧周波数変換手段と、 充放電手段からの放電電流が動作電力用に供給 され、 電圧周波数変換手段から出力される計測信号を外部に伝送する伝送手段と、 を有することを特徴とするものである。 本発明によれば、 電力調達機能と電流計測機能を分離して、 電流計測機能とし て電圧周波数変換手段を用い、 充放電手段からの放電電流を、 電圧周波数変換手 段の動作電力用としてのみ用いるため、 素子のバラツキや温度特性に影響を受け ることがなくなる。 In order to achieve the above-described object, an AC current measuring apparatus according to the present invention includes a transformer for generating a secondary current on a secondary side by a primary AC current flowing on a primary side, and a secondary current generated by the transformer. Means for rectifying the current, charging and discharging means for charging and discharging the current rectified by the rectifying means, and charging the charging and discharging means until the voltage generated by the secondary current reaches a predetermined value. Charging / discharging control means for controlling to discharge when the value is higher than the value, load resistance provided in the circuit through which the secondary current flows, and discharging current from the charging / discharging means is supplied for operating power and generated by the load resistance Voltage-frequency conversion means for converting a voltage value to a frequency value, and transmission means for supplying a discharge current from the charging / discharging means for operating power and transmitting a measurement signal output from the voltage-frequency conversion means to the outside. Yes It is characterized by doing. According to the present invention, the power procurement function and the current measurement function are separated, and the voltage frequency conversion means is used as the current measurement function, and the discharge current from the charging / discharging means is used only for the operating power of the voltage frequency conversion means. Since it is used, it is not affected by the variation of the element and the temperature characteristic.
上記充放電制御手段は、 二次電流で生成される電圧が所定値より高くなると電 流が流れるッヱナ一ダイォードと、 そのツエナ一ダイォ一ドに電流が流れると、二 次電流で生成される電圧を飽和電圧まで下げるサイリスタと、 そのサイリスタに 充放電手段からの放電電流が逆流するのを防止する逆流防止用ダイォードと、 を 有するのが好ましい。 この場合、 二次電流によって誘起される電圧が大きい場合 でも、 サイリス夕が ONして、 サイリスタの飽和電圧まで低下するので、 処理回路 全体の消費電力を低減することができる。  The charge / discharge control means includes: a zener diode in which a current flows when the voltage generated by the secondary current becomes higher than a predetermined value; and a voltage generated by the secondary current when a current flows in the zener diode. Preferably, the thyristor includes a thyristor that reduces the current to a saturation voltage, and a backflow prevention diode that prevents the discharge current from the charging / discharging means from flowing back into the thyristor. In this case, even when the voltage induced by the secondary current is large, the thyristor turns on and the voltage drops to the saturation voltage of the thyristor, so that the power consumption of the entire processing circuit can be reduced.
充放電手段からの放電電流によって生成される電圧が設定された動作停止電圧 値より低くなると放電電流の供給を停止させ、 設定された動作開始電圧値より高 くなると放電電流の供給を開始するように切り換える切換手段を、 さらに有して もよい。 この場合、 一次交流電流が微弱な場合であっても、 電圧周波数変換手段 を間欠動作させることができるので、 電流計測を行うことができる。  When the voltage generated by the discharge current from the charging / discharging means becomes lower than the set operation stop voltage value, the supply of the discharge current is stopped, and when the voltage becomes higher than the set operation start voltage value, the supply of the discharge current is started. Switching means for switching between the two may be further provided. In this case, even if the primary alternating current is weak, the voltage-frequency converter can be operated intermittently, so that current measurement can be performed.
上記整流手段は、 二次電流を全波整流するものでもよく、 二次電流を半波整流 するものでもよい。 図面の簡単な説明  The rectifier may be one that performs full-wave rectification on the secondary current or one that performs half-wave rectification on the secondary current. BRIEF DESCRIPTION OF THE FIGURES
図 1は、本発明の第 1の実施の形態に係る交流電流計測装置を示す回路図である。 図 2 (A) は一次交流電流 の波形図、 （B) は二次電流 i2の波形図、 （C) は電圧 ¼の波形図、 （D) は電圧 V2の波形図である。 FIG. 1 is a circuit diagram showing an AC current measuring device according to a first embodiment of the present invention. 2 (A) is a waveform diagram of a primary alternating current, (B) shows a waveform of the secondary current i 2, (C) is a waveform diagram of the voltage ¼, (D) is a waveform diagram of the voltage V 2.
図 3 (A) は電圧 V3の波形図、 （B) は電圧 V4の波形図、 （C) は電圧 V5の波形 図である。 3 (A) is a waveform diagram of the voltage V 3, (B) shows a waveform of the voltage V 4, a waveform diagram (C) the voltage V 5.
図 4は、本発明の第 2の実施の形態に係る交流電流計測装置を示す回路図である。 図 5 (A) は一次交流電流 の波形図、 （B) は二次電流 i2の波形図、 （C) は電圧 V,の波形図、 （D) は電圧 V2の波形図である。 FIG. 4 is a circuit diagram showing an AC current measuring device according to a second embodiment of the present invention. 5 (A) is a waveform diagram of the primary alternating current, (B) is a waveform diagram of the secondary current i 2 , (C) is a waveform diagram of the voltage V, and (D) is a waveform diagram of the voltage V 2 .
図 6は、本発明の第 3の実施の形態に係る交流電流計測装置を示す回路図である。 図 7は、 （A) は一次交流電流 の波形図、 （B) は電圧 V,の波形図である。 図 8は、 第 1の実施の形態における電圧 V3の波形図である。 FIG. 6 is a circuit diagram showing an AC current measuring device according to a third embodiment of the present invention. 7A is a waveform diagram of the primary alternating current, and FIG. 7B is a waveform diagram of the voltage V. Figure 8 is a waveform diagram of the voltage V 3 in the first embodiment.
図 9は、本発明の第 4の実施の形態に係る交流電流計測装置を示す回路図である。 図 10 (A) は電圧 V6の波形図、 （B) は電圧 V2の波形図、 （C) は電圧 V3の波形 図、 （D) は電圧 V4の波形図、 （E) は電圧 V5の波形図である。 FIG. 9 is a circuit diagram showing an AC current measuring device according to a fourth embodiment of the present invention. Figure 10 (A) shows a waveform of the voltage V 6, (B) shows a waveform of the voltage V 2, (C) shows a waveform of the voltage V 3, (D) shows a waveform of the voltage V 4, (E) is it is a waveform diagram of the voltage V 5.
図 11は、 従来の交流電流計測装置を示す回路図である。 発明を実施するための最良の形態  FIG. 11 is a circuit diagram showing a conventional AC current measuring device. BEST MODE FOR CARRYING OUT THE INVENTION
以下、 本発明の実施の形態を、 図面を参照して説明する。 図 1は、 本発明の第 1 の実施の形態に係る交流電流計測装置を示す回路図である。  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram showing an AC current measuring device according to a first embodiment of the present invention.
図 1に示すように、 変成器 1の二次側のコイル 3には整流回路 4が接続される。 整流回路 4は、 4つのダイォ—ドで構成されるプリ ッジ回路であり、 導体 2に流れ る一次交流電流 i,によつて変成器 1の二次側のコイル 3に発生する二次電流 i2を全 波整流する。 整流回路 4には、 逆流防止用のダイォ—ド 5 (順方向電圧 Vf) を介し て二次電流 i2を充電するコンデンサ 6が接続される。 As shown in FIG. 1, a rectifier circuit 4 is connected to the secondary coil 3 of the transformer 1. The rectifier circuit 4 is a bridge circuit composed of four diodes, and a secondary current generated in the secondary coil 3 of the transformer 1 by a primary alternating current i flowing through the conductor 2. i 2 is full-wave rectified. The rectifier circuit 4 is connected to a capacitor 6 for charging a secondary current i 2 via a diode 5 for preventing reverse current (forward voltage V f ).
また、 整流回路 4とダイォ一 ド 5のァノードとの間には、 コンデンサ 6の充電電 圧が定電圧よりも高くなると電流が流れるッヱナ一ダイオード 7と、 ッヱナ一ダイ ォ一ド 7に電流が流れると ONして二次電流 i2で生成される電圧 V,を飽和電圧 Vs まで下げるサイリスタ 8が並列に接続される。 サイリスタ 8のゲートはツエナ一ダ ィオード 7のアノードと抵抗 9との間に接続される。 In addition, a current flows between the rectifier circuit 4 and the anode of the diode 5 when a charging voltage of the capacitor 6 becomes higher than a constant voltage, and a current flows through the diode 7 and the diode 7. thyristor 8 to decrease the voltage V, which is generated by the secondary current i 2 is turned oN when the flow to the saturation voltage V s is connected in parallel. The gate of thyristor 8 is connected between the anode of zener diode 7 and resistor 9.
コンデンサ 6及びダイォ一ド 5のカソ一ドには、 電流計測に必要な電力を調達す るための電力調達用経路 K,を介して、 電圧 周波数変換回路 10 (以下、 V/F変 換回路という） 及び電気/光変換回路 11 (以下、 E/0変換回路という） が接続さ れる。 V/F変換回路 10としては、 例えば、 米国バーブラウン社製の VFC62B等 を用いるのが好ましい。 この装置は、一 20 °C〜70 °Cの範囲内で非直線性 0.004 % という、 個別素子の組合せでは達成が極めて難しい精度を実現できる。 E/0変換 回路 11としては、 発光ダイォ一ドを用いてもよい。  The capacitors of the capacitor 6 and the diode 5 are connected to a voltage / frequency conversion circuit 10 (hereinafter referred to as a V / F conversion circuit) via a power procurement path K for procuring power required for current measurement. ) And an electrical / optical conversion circuit 11 (hereinafter referred to as an E / 0 conversion circuit). As the V / F conversion circuit 10, it is preferable to use, for example, VFC62B manufactured by Burr Brown Inc. in the United States. This device can achieve an accuracy of 0.004% non-linearity in the range of 20 ° C to 70 ° C, which is extremely difficult to achieve with a combination of individual elements. As the E / 0 conversion circuit 11, a light emitting diode may be used.
V 変換回路 10と整流回路 4との間には、 電流を計測するための信号を F変換回路 10に送るための電流計測用経路 K2 (Κ,と区別するため、 点線で示す） が設けられる。 電流計測用経路 K2の一端は、 整流回路 4と負荷抵抗 12との間に接 続され、 他端は V/ 変換回路 10に接続される。 負荷抵抗 12、 抵抗 9及びコンデ ンサ 6の一端並びにサイリスタ 8のカソ一ドは接地される。 Between the V conversion circuit 10 and the rectifier circuit 4, a current measurement path K 2 for sending a current measurement signal to the F conversion circuit 10 (shown by a dotted line to distinguish it from Κ) Is provided. One end of the current measurement path K 2 is connected between the rectifying circuit 4 and the load resistor 12, the other end is connected to the V / converter 10. One end of the load resistor 12, the resistor 9, the capacitor 6, and the cathode of the thyristor 8 are grounded.
Ε/0変換回路 11は、光ファイバ 13を介して信号伝送先の光/電気変換部 14 (以 下、 ΟΖΕ変換部という） に接続され、 0/Ε変換部 14は、 周波数 電圧変換部 15 The Ε / 0 conversion circuit 11 is connected via an optical fiber 13 to an optical / electrical conversion unit 14 (hereinafter referred to as ΟΖΕ conversion unit) of a signal transmission destination, and the 0 / Ε conversion unit 14 includes a frequency / voltage conversion unit 15
(以下、 FZV変換部という） に接続される。 (Hereinafter referred to as FZV converter).
次に、 第 1の実施の形態の動作を説明する。 まず、 測定対象となる導体 2に図 2 (Α) に示すような波形の第 1交流電流 i, (例えば、 50Hzあるいは 60Hz) が流れ ているものとする。  Next, the operation of the first embodiment will be described. First, it is assumed that a first alternating current i (for example, 50 Hz or 60 Hz) having a waveform as shown in FIG. 2 (Α) is flowing through the conductor 2 to be measured.
この第 1交流電流 によって、 変成器 1に巻かれたコイル 3に電圧が生じ、 二次 電流 i2が流れる （コイル 3の巻線数を Nとすると、 i2 = ί,ΖΝとなる）。 二次電流 i2は、 整流回路 4、 ダイオード 5を介してコンデンサ 6に流れ充電される。 This first alternating current generates a voltage in the coil 3 wound around the transformer 1 and causes a secondary current i 2 to flow (assuming that the number of turns of the coil 3 is N, i 2 = ί, ΖΝ). The secondary current i 2 flows through the rectifier circuit 4 and the diode 5 to the capacitor 6 and is charged.
コンデンサ 6の放電電流は、 電力調達用経路 を介して、 V/F変換回路 10及 び E/0変換回路 11に流れる。 従って、 VZF変換回路 10及び EZO変換回路 11 に対する動作電力の供給を内部で行うことができる。  The discharge current of the capacitor 6 flows to the V / F conversion circuit 10 and the E / 0 conversion circuit 11 via the power procurement path. Therefore, it is possible to supply operating power to the VZF conversion circuit 10 and the EZO conversion circuit 11 internally.
二次電流 i2によって誘起される電圧のうち、 ッヱナ一ダイォ一ド 7のカソ一ドに おける電圧 V！の波形は図 2 (C) に示すようになる。 あらかじめ、 ッヱナ一ダイォ一 ドアの定電圧 V™は、 後段の回路 （VZF変換回路 10及び EZO変換回路 11) が 必要とする電圧 V3より、 ダイォ一ド 5の順方向電圧 V,だけ大きい値に設定されて いる。 また、 この電圧 V3は、 図 3 (A) に示すように、 コンデンサ 6により平滑化' 直流化され定電圧 VD (VD = V™ - V,) となる。 例えば、 後段の処理回路の必要電 圧が 5Vで、 ダイォード 5の順方向電圧 V,が 0.7Vの場合には VTHは 5.7Vに設定 すればよい。 仮に、一次交流電流 i,が大きく、 従って、 二次電流 i2によって誘起さ れる電圧が大きい場合でも、 V™を超える分については、 サイリスタ 8が ONし V！ の電圧はサイリスタ 8の飽和電圧である Vsまで低下する。 その結果、 処理回路全 体の消費電力が低減され （サイリスタ 8の飽和電圧 Vsが、 仮に、 1.5Vとすると回 路の消費電力は約 1.5Wとなる）、 発熱による二次電流 i2への影響を低減できる。 ここで、 変成器 1は直流を通さないため、 一定時間毎に二次電流 i2は必ず 0にな る。 そのため、 サイリスタ 8は必ず OFFし、 前の周期と同じ動作を繰り返すこと になる （図 2 (C) 参照）。 例えば、 二次電流 i2が 50Hzの正弦波の場合、 10msec 毎に、同じ動作を繰り返すことになる。 この動作を考えれば、ダイォ一ド 5のカソー ド側に接続されたコンデンサ 6の容量は、後段の処理回路による電流消費を 10msec の間だけ賄える値とすればよいことがわかる。 Among the voltages induced by the secondary current i 2 , the voltage V at the cathode of the diode diode 7! The waveform of is shown in Fig. 2 (C). Previously, the constant voltage V ™ of Wwena one Daio one door, the voltage V 3 to the subsequent circuit (VZF converter 10 and EZO conversion circuit 11) requires, the forward voltage V, only large value of Daio one de 5 Is set to. Further, as shown in FIG. 3 (A), the voltage V 3 is smoothed and converted to DC by the capacitor 6 to become a constant voltage V D (V D = V ™ −V,). For example, if the required voltage of the subsequent processing circuit is 5 V and the forward voltage V, of the diode 5 is 0.7 V, V TH may be set to 5.7 V. Even if the primary AC current i is large and the voltage induced by the secondary current i 2 is large, the thyristor 8 turns ON and V! Voltage drops to Vs, which is the saturation voltage of thyristor 8. As a result, the power consumption of the processing circuit overall is reduced (saturation voltage V s of the thyristor 8, if the power consumption of When 1.5V circuits is about 1.5 W), heat generation due to the secondary current i 2 Can be reduced. Here, since the transformer 1 does not pass a direct current, the secondary current i 2 always becomes 0 at regular intervals. Therefore, thyristor 8 must be turned off and repeat the same operation as the previous cycle. (See Fig. 2 (C)). For example, when the secondary current i 2 is a sine wave of 50 Hz, the same operation is repeated every 10 msec. Considering this operation, it can be seen that the capacity of the capacitor 6 connected to the cathode side of the diode 5 should be set to a value that can cover the current consumption by the subsequent processing circuit for only 10 msec.
また、 ダイオード 5は、 サイリスタ 8の ON時の飽和電圧 Vsが、 V3の電圧より 低いので、 コンデンサ 6に蓄積された電荷が、 ONしたサイリス夕 8側に逆流する のを防止する。 Further, since the saturation voltage V s of the thyristor 8 at the time of ON of the thyristor 8 is lower than the voltage of V 3 , the diode 5 prevents the charge accumulated in the capacitor 6 from flowing back to the thyristor 8 at the ON time.
一方、 変成器 1は負荷抵抗 12が極端に大きくない限りにおいて、 定電流源とし て作用する。 従って、 変成器 1は、 整流回路 4のダイォ—ドの順方向電圧及びサイ リスタ 8の ON時の飽和電圧 Vsのバラツキ、 温度特性による変化には関係なく定 電流である二次電流 i2を流すように、 自らの発生電圧を調整する機能がある。 従って、 負荷抵抗 12には、 導体 2に流れる電流と巻線数 Nを正確に反映させた 二次電流 i2が流れることになる。 第 1の実施の形態では、 整流回路 4が全波整流す るので、 負荷抵抗 12には、 図 2 (B) に示すように、 全波整流波形である電流 i2が 流れることになる。 On the other hand, the transformer 1 acts as a constant current source as long as the load resistance 12 is not extremely large. Therefore, the transformer 1 generates the secondary current i 2 which is a constant current regardless of the variation of the forward voltage of the diode of the rectifier circuit 4 and the variation of the saturation voltage Vs when the thyristor 8 is turned on, and the change due to the temperature characteristic. It has a function to adjust its own generated voltage so that it flows. Therefore, a secondary current i 2 that accurately reflects the current flowing through the conductor 2 and the number of windings N flows through the load resistor 12. In the first embodiment, since the rectifier circuit 4 performs full-wave rectification, a current i 2 having a full-wave rectified waveform flows through the load resistor 12 as shown in FIG. 2B.
この二次電流 i2は負荷抵抗 12によって、 図 2 (D) に示すような波形の電圧 V2 が生じる （図 2 (D) では基準電位を図 1のようにとるとマイナス極性になる）。 こ の電圧 V2は、 電流計測経路 K2の一端に設けられた VZF変換回路 10によって、 図 3 (Β) に示すように、 パルス列の周波数に変換される。 変換された周波数の計測 信号は、 Ε/0変換回路 11によって、 光信号に変換され、 その光信号は、 光ファ ィバ 13によって絶縁された遠隔地に伝送される。 伝送された光信号は、 ΟΖΕ変 換部 14及び F/V変換部 15によって、 図 3 (C) に示す復調電圧 V5に復調される。 これによつて、 絶縁された観測地で導体 2に流れる電流を計測することができる。 第 1の実施の形態によれば、 サイリスタ 8及びッヱナ一ダイォ一ド 7をコンデン サ 6よりも前段に配置し、 電流計測のための負荷抵抗 12を設けたので、 1つの変 成器 1で電流計測と電力調達を同時に行うことができるとともに、 従来技術で、 電 力調達と電流計測の 2つの機能を行っていたコンデンサ 6を電力調達のみに用い、 電流計測には用いないようにした。 これによつて、 素子のバラツキや温度特性に 影響を受けることがなくなる。 従って、 製品間の特性のバラツキを抑え広い温度 範囲で高精度の電流計測が可能となる。 This secondary current i 2 generates a voltage V 2 having a waveform as shown in FIG. 2 (D) due to the load resistance 12 (in FIG. 2 (D), the reference potential becomes negative as shown in FIG. 1). . This voltage V 2 is converted into a pulse train frequency by a VZF conversion circuit 10 provided at one end of the current measurement path K 2 , as shown in FIG. The converted frequency measurement signal is converted into an optical signal by the Ε / 0 conversion circuit 11, and the optical signal is transmitted to a remote place insulated by the optical fiber 13. Transmitted optical signal by ΟΖΕ varying section 14 and F / V converter 15 is demodulated into demodulated voltage V 5 shown in Figure 3 (C). As a result, the current flowing through the conductor 2 can be measured at the insulated observation site. According to the first embodiment, the thyristor 8 and the antenna diode 7 are arranged before the capacitor 6 and the load resistor 12 for measuring the current is provided. Current measurement and power procurement can be performed at the same time, and the capacitor 6 that performed the two functions of power procurement and current measurement in the conventional technology is used only for power procurement, and not used for current measurement. As a result, it is not affected by the variation of the element and the temperature characteristic. Therefore, the variation in characteristics between products is suppressed High-precision current measurement is possible in the range.
また、 電力調達機能のためにサイリス夕 8を利用したので、 後段の処理回路が必 要としない電力は最小限の電力を除き、 取り込まないので、 発熱を抑えることが できる。 これにより、広い電流計測範囲が得られる。 特に、一次交流電流 が大き く、 二次電流 i2が大きくなっても、 発熱が小さく、 二次電流 i2の大電流側で有効で ある。 In addition, since the thyristor 8 is used for the power procurement function, power that is not required by the subsequent processing circuit is not taken in except for the minimum power, so that heat generation can be suppressed. Thereby, a wide current measurement range can be obtained. In particular, the primary alternating current is rather large, even if a large secondary current i 2, heating is small, effective at high current side of the secondary current i 2.
次に、 本発明の第 2の実施の形態を説明する。 図 4に示すように、 第 2の実施の 形態に係る交流電流計測装置では、二次電流 i2を半波整流するためにダイォード 20 が用いられる。 従って、 図 5 (A) に示すような一次交流電流 i,が流れている場合、 負荷抵抗 12には、 図 5 (B) に示すように、 半波整流波形である電流 i2が流れるこ とになる。 また、 ツエナ一ダイオード 7の力ソー ドの電圧 V,及びコイル 3と負荷 抵抗 12との間の電圧 V2は、 それぞれ図 5 (C) 及び図 5 (D) に示すような波形と なる。 Next, a second embodiment of the present invention will be described. As shown in FIG. 4, in the AC current measuring device according to the second embodiment, a diode 20 is used to half-wave rectify the secondary current i 2 . Therefore, when the primary alternating current i, as shown in FIG. 5 (A), flows, the current i 2 having a half-wave rectified waveform flows through the load resistance 12, as shown in FIG. 5 (B). And Further, the voltage V of the force source of the Zener diode 7 and the voltage V 2 between the coil 3 and the load resistor 12 have waveforms as shown in FIGS. 5 (C) and 5 (D), respectively.
次に、 本発明の第 3の実施の形態を説明する。 図 6に示すように、 第 3の実施の 形態に係る交流電流計測装置では、 第 1の実施の形態のように、 サイリス—夕 8を用 いずに、 例えば、 定電圧 5.7Vのツエナ一ダイォ一ド 30が用いられる。 従って、 図 7 (A) に示すような一次交流電流 i,が流れている場合、 ッヱナ—ダイオード 7の 力ソー ドの電圧 V,は、 図 7 (B) に示すように、 一定期間 V™になる。 第 3の実施 の形態では、 第 1の実施の形態のようにサイリスタ 8を用いないので、 部品点数を 少なくすることができ、 構造を簡単にすることができる。  Next, a third embodiment of the present invention will be described. As shown in FIG. 6, in the AC current measuring apparatus according to the third embodiment, as in the first embodiment, a zenither having a constant voltage of 5.7 V is used without using a thyristor 8. Diode 30 is used. Therefore, when the primary alternating current i, as shown in FIG. 7 (A), flows, the voltage V, of the power source of the zener diode 7, becomes as shown in FIG. become. In the third embodiment, since the thyristor 8 is not used unlike the first embodiment, the number of parts can be reduced, and the structure can be simplified.
次に、 本発明の第 4の実施の形態を説明する。 第 1の実施の形態に係る交流電流 計測装置では、 一次交流電流 i,が十分に大きい場合、 電圧 V3は図 3 (A) に示すよ うな波形となり、 電圧 VDは、 V/F変換回路 10及び EZO変換回路 11の動作保証 電圧を上回り、安定動作するため、 図 3 (B) に示す出力電圧 V4が得られる。 しか し、一次交流電流 が小さくなるに従って VDは小さくなり、図 8に示すように、電 圧 V3が回路の動作保証電圧 VKを下回ると、 回路の動作は停止する。 従って、 第 1 の実施の形態では、 動作電流の下限 （ilmin) が決められており、 動作下限電流 in 以下については、 測定が不可能となる。 Next, a fourth embodiment of the present invention will be described. The alternating current measuring device according to the first embodiment, when the primary AC current i, is sufficiently large, the voltage V 3 becomes I UNA waveform shown in FIG. 3 (A), the voltage V D, V / F converter The output voltage V 4 shown in FIG. 3 (B) is obtained because the operation exceeds the operation guarantee voltage of the circuit 10 and the EZO conversion circuit 11 and operates stably. However, V D decreases as the primary alternating current decreases, and as shown in FIG. 8, when the voltage V 3 falls below the operation guarantee voltage V K of the circuit, the operation of the circuit stops. Therefore, in the first embodiment, the lower limit (i lmin ) of the operating current is determined, and it becomes impossible to measure the lower limit of the operating current in .
一方、 動作保証電圧 VKを下回ったとはいえ、 VZF変換回路 10及び E/0変換 回路 11に対して電力供給がなされているので、 動作をしない回路で無駄な電力を 消費していることになる。 また、 変成器 1の一般的な特性として、 接続された回路 が電流消費した場合にはそれに伴い発生電圧が低下する性質があるため、 ある動 作下限電流以下では動作保証電圧を下回り、 回路が動作しない。 Meanwhile, although the lower than the guaranteed operating voltage V K, VZF conversion circuit 10 and E / 0 converter Since power is supplied to the circuit 11, useless power is consumed by the circuit that does not operate. In addition, as a general characteristic of the transformer 1, when the connected circuit consumes current, the generated voltage decreases in accordance with the current consumption. Do not work.
そこで、 第 4の実施の形態は、 所定の電圧まで低下した場合、 積極的に、 VZF 変換回路 10と EZO変換回路 11の電力供給を遮断することを特徴とするものであ る。  Thus, the fourth embodiment is characterized in that when the voltage drops to a predetermined voltage, the power supply to the VZF conversion circuit 10 and the EZO conversion circuit 11 is positively cut off.
図 9は、本発明の第 4の実施の形態に係る交流電流計測装置を示す回路図である。 第 4の実施の形態に係る交流電流計測装置は、 第 1の実施の形態に回路動作切換部 40が追加して設けられる。 この回路動作切換部 40は、 回路動作開始電圧設定用ッ ェナ一ダイォ一ド 41と、 回路動作の ON/OFFのスィツチングを行う PNP形の トランジス夕 42と、 トランジス夕 42を制御するサイ リスタ 43と、 回路動作停止 電圧設定用ッヱナ一ダイォ—ド 44と、 抵抗 45、 46とを有する。  FIG. 9 is a circuit diagram showing an AC current measuring device according to a fourth embodiment of the present invention. The AC current measurement device according to the fourth embodiment is provided with a circuit operation switching unit 40 added to the first embodiment. The circuit operation switching section 40 includes a circuit diode 41 for setting a circuit operation start voltage, a PNP-type transistor 42 for switching ON / OFF of the circuit operation, and a thyristor for controlling the transistor 42. 43, a circuit diode for stopping the circuit operation, a voltage setting diode 44, and resistors 45 and 46.
トランジスタ 42のエミ ッタは、 回路動作開始電圧設定用ッヱナ一ダイォ一ド 41 のカソ一ドに接続され、 そのベースは、 サイリスタ 43のァノ一ドに接続され、 そ のコレクタは、 Vノ F変換回路 10及び E/0変換回路 11に接続される。  The emitter of the transistor 42 is connected to the cathode of a circuit diode 41 for setting the circuit operation start voltage, the base is connected to the anode of the thyristor 43, and the collector is connected to the V node. Connected to F conversion circuit 10 and E / 0 conversion circuit 11.
また、 サイリスタ 43のゲートは、 回路動作開始電圧設定用ッヱナ一ダイオード 41と抵抗 45との間に接続され、 そのカソ一ドは、回路動作停止電圧設定用ッヱナ一 ダイォ一ド 44のカソ一 ドに接続される。  Further, the gate of the thyristor 43 is connected between the circuit diode 41 for setting the circuit operation start voltage and the resistor 45, and its cathode is connected to the cathode of the circuit diode 44 for setting the circuit operation stop voltage. Connected to.
次に、 第 4の実施の形態の動作を説明する。 一次交流電流 が十分大きく、 回路 に対する供給電力が豊富な場合は、 ッニナ一ダイォ一ド 7で設定される定電圧によ つて、 電圧 V3は、 VC0NTの値になる。 これにより回路動作開始電圧設定用ツエナ— ダイォ—ド 41の設定電圧 V0Nは、 ッヱナ—ダイォード 7の設定電圧 VC0NTより小さ いので、 常に ON状態になる。 これによつて、 トランジスタ制御用のサイリスタ 43は ONし、 トランジスタ 42は ONになるので、 後段の V/F変換回路 10及び ENext, the operation of the fourth embodiment will be described. When the primary alternating current is sufficiently large and the power supplied to the circuit is abundant, the voltage V 3 becomes the value of V C0NT by the constant voltage set by the ninina diode 7. As a result, the setting voltage V 0N of the circuit diode 41 for setting the circuit operation start voltage is smaller than the setting voltage V C0NT of the zener diode 7, so that the circuit is always turned on. As a result, the thyristor 43 for transistor control is turned on and the transistor 42 is turned on, so that the V / F conversion circuit 10 and E
/0変換回路 11には常に電力供給され、 これらの回路は連続動作することになる。 一次交流電流 ΰが減少し、 後段の処理回路の電力を賄いきれなくなつてくると、 コンデンサ 6の両端電圧 V3は低下してくる。 この電圧 V3が、 回路動作停止電圧設 定用ッヱナ一ダイオード 44の設定電圧 V0FFを下回ると、 ダイオード 5の電流が遮 断し、 トランジスタ制御用のサイ リスタ 43は OFFになる。 これによつて、 トラン ジスタ 42も OFFし、 後段の V/F変換回路 10及び EZO変換回路 11への電力を 遮断する。 Power is always supplied to the / 0 conversion circuit 11, and these circuits operate continuously. When the primary alternating current 減少 decreases and the power of the subsequent processing circuit cannot be supplied, the voltage V 3 across the capacitor 6 decreases. When this voltage V 3 falls below the set voltage V 0FF of the circuit operation stop voltage setting diode 44, the current of the diode 5 is interrupted. And the thyristor 43 for transistor control is turned off. As a result, the transistor 42 is also turned off, and the power to the V / F conversion circuit 10 and the EZO conversion circuit 11 at the subsequent stage is cut off.
トランジスタ 42が OFFして、 後段の V ZF変換回路 10及び E /0変換回路 11 が遮断されると、 変成器 1の負荷が大きくなるので、 電圧 V,が大きくなる。 この 電圧 V,はコンデンサ 6を充電し、 蓄積された電荷に比例して電圧 V3は徐々に昇圧 することになる。 When the transistor 42 is turned off and the subsequent VZF conversion circuit 10 and E / 0 conversion circuit 11 are cut off, the load on the transformer 1 increases, and the voltage V increases. The voltage V, charges the capacitor 6, the voltage V 3 in proportion to the accumulated charge will be gradually boosted.
この電圧 V3が回路動作開始電圧設定用ツエナ—ダイオード 41の設定電圧 V。nを 超えると トランジス夕 42が ONし、 後段の V/F変換回路 10および E/0変換回 路 1 1に電力が供給され動作を開始する。 This voltage V 3 is the set voltage V of the zener diode 41 for setting the circuit operation start voltage. When n is exceeded, the transistor 42 is turned on, and power is supplied to the subsequent stage V / F conversion circuit 10 and E / 0 conversion circuit 11 to start operation.
VON > VOFFと設定することにより、本回路はヒステリ シス特性を持つようになり、 V0Nから V0FFに至る一定時間は後段回路が動作し、 それ以外の時間は、 これら後段 の回路は動作を停止し、 コンデンサ 6に電荷が蓄積されるようになる。 このとき、 トランジスタ 42のコレクタ側の電圧 V6は、 図 10 (A) に示すように変化する。 ま た、 V0FFを回路の動作保証電圧 VK以上に設定すれば、 V0N→ V0FFの期間は後段の 処理回路を確実に動作させることができる。 By setting the VON> VOFF, the circuit will have a hysteresis characteristic, a predetermined time is operation subsequent circuit leading to V 0FF from V 0N, the other times, these subsequent circuit operation The operation stops, and electric charge is accumulated in the capacitor 6. At this time, the voltage V 6 on the collector side of the transistor 42 changes as shown in FIG. Further, if V 0FF is set to be equal to or higher than the operation guarantee voltage V K of the circuit, the processing circuit at the subsequent stage can be reliably operated during the period from V 0N → V 0FF .
電圧 V2、 電圧 V3、 電圧 V4及び電圧 V5は、 それぞれ図 10 (B) 〜図 10 (E) に 示すようになる。 負荷抵抗 12の両端に発生する電圧 V2は、 図 10 (B) に示すよう に、 第 1の実施の形態と同じになる。 また、 VZF変換回路 10及び Ε Ό変換回路 1 1は、 図 10 (A) に示すように、 V0N→V0FFの期間のみ動作するので、 V /F変換 回路 10の出力電圧 V4は上記期間のみ得られて、 図 10 (D) に示すようになる。 従 つて、 伝送先の出力電圧 （復調電圧） V5は、 図 10 (E) の実線部分になる。 なお、 図 10 (E) に示す実線部分から信号の途絶 る点線部分は推定により補間するこ とが可能である。 Voltage V 2, the voltage V 3, the voltage V 4 and the voltage V 5 are as shown in FIGS 10 (B) ~ FIG 10 (E). Voltage V 2 generated at both ends of the load resistor 12, as shown in FIG. 10 (B), the same as the first embodiment. Also, as shown in FIG. 10 (A), the VZF conversion circuit 10 and the ΌΔ conversion circuit 11 operate only during the period of V 0N → V 0FF , so that the output voltage V 4 of the V / F conversion circuit 10 is Only the period is obtained, as shown in Figure 10 (D). Accordance connexion, transmission destination of the output voltage (demodulated voltage) V 5 becomes the solid line portion in FIG. 10 (E). Note that the broken line from the solid line shown in Fig. 10 (E) can be interpolated by estimation.
以上説明したように、 ツエナ—ダイオー ド 7の設定電圧 V∞NT、 回路動作開始電 圧設定用ツエナ—ダイォ—ド 41の設定電圧 V。N、 回路動作停止電圧設定用ッ ナー ダイオード 44の設定電圧 V0FFを、 VCONT > VON > VOFFとすることにより、 V3 > VON の期間では連続動作を行い、 V0N〉V3 > V0FFの下降期間では、間欠動作を行い、 V0FF As described above, the set voltage V∞NT of the zener diode 7 and the set voltage V of the zener diode 41 for setting the circuit operation start voltage. N, the set voltage V 0FF circuit operation stop voltage setting Tsu zener diode 44, VCONT>VON> With VOFF, performs a continuous operation for a period of V 3> V ON, V 0N > V 3> V 0FF Intermittent operation is performed during the falling period of V 0FF
> V3の期間では、 間欠動作が停止する。 また、 一度 V0FFを下回った後の V0N > V3 > V0FFの上昇期間では間欠動作の停止期間となる （図 10 (C) 参照）。 > In the period of V 3, the intermittent operation is stopped. Also, V 0N > V 3 once the voltage falls below V 0FF > During the rising period of V0FF , the intermittent operation is stopped (see Fig. 10 (C)).
第 4の実施の形態によれば、 —次電流が低い場合であっても電流計測が可能とな り、 また、 回路動作停止電圧 V0FFを回路動作保証電圧 VKより高く設定することに より、 回路動作保証電圧 VK近傍における回路の不安定動作を回避できる。 According to the fourth embodiment, current measurement can be performed even when the next current is low, and the circuit operation stop voltage V 0FF is set higher than the circuit operation assurance voltage V K. It can avoid unstable operation of the circuit in the circuit operation guarantee voltage V K vicinity.
本発明は、 上記実施の形態に限定されることはなく、 特許請求の範囲に記載さ れた技術的事項の範囲内において、 種々の変更が可能である。 例えば、 内部で電 力供給を行っているので、 Ε Ό変換回路 11を、 例えば、 米国特許第 4384289号 公報に開示されているような無線伝送装置に置き換えることもできる。 また、 第 3の実施の形態及び第 4の実施の形態における整流回路 4を 1つのダイオードに代 えて、 二次電流 i2を半波整流するようにしてもよい。 産業上の利用可能性 The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the technical matters described in the claims. For example, since power is supplied internally, the power conversion circuit 11 can be replaced with a wireless transmission device as disclosed in, for example, US Pat. No. 4,384,289. Further, the rectifier circuit 4 in the third and fourth embodiments may be replaced with one diode, and the secondary current i 2 may be half-wave rectified. Industrial applicability
本発明によれば、 次のような優れた効果を発揮して、 産業上利用することがで きる。  ADVANTAGE OF THE INVENTION According to this invention, the following outstanding effects are exhibited and it can be used industrially.
(1) 電力調達機能と電流計測機能を分離して、 電流計測機能として電圧周波数変 換手段を用い、 充放電手段からの放電電流を、 電圧周波数変換手段の動作電力用 としてのみ用いるため、 素子のバラツキや温度特性に影響を受けることがなくな る。 従って、 製品間の特性のバラツキを抑え、 広い温度範囲で高精度の電流計測 が可能となる。  (1) Separate the power procurement function and the current measurement function, use the voltage frequency conversion means as the current measurement function, and use the discharge current from the charging / discharging means only for the operating power of the voltage frequency conversion means. It is no longer affected by variations in temperature and temperature characteristics. Therefore, variation in characteristics between products can be suppressed, and highly accurate current measurement can be performed in a wide temperature range.
(2) 分離された電力調達機能と電流計測機能を 1つの変成器によって実現できる ので、 装置の小型化を図ることができる。  (2) Since the separate power procurement function and current measurement function can be realized by a single transformer, the size of the device can be reduced.
(3) 電力調達機能と電流計測機能を分離したので、 光ファイバによる伝送方式を 他の無線による伝送方式等に置き換えることが容易になる。  (3) Since the power procurement function and the current measurement function are separated, it becomes easy to replace the transmission method using an optical fiber with another wireless transmission method.

Claims

請 求 の 範 囲 The scope of the claims
1. 一次側に流れている一次交流電流によって二次側に二次電流を発生させる 変成器と、 1. a transformer that generates a secondary current on the secondary side by a primary alternating current flowing on the primary side;
その変成器で発生した二次電流を整流する整流手段と、  Rectifying means for rectifying the secondary current generated by the transformer;
その整流手段で整流された電流を充電及び放電する充放電手段と、 その充放電手段を、 前記二次電流で生成される電圧が所定値になるまで充電 させ、 所定値より高くなると放電するように制御する充放電制御手段と、 前記二次電流が流れる回路に設けられる負荷抵抗と、  Charging and discharging means for charging and discharging the current rectified by the rectifying means; charging and discharging the charging and discharging means until the voltage generated by the secondary current reaches a predetermined value; and discharging when the voltage is higher than a predetermined value. Charge and discharge control means, and a load resistance provided in a circuit through which the secondary current flows,
前記充放電手段からの放電電流が動作電力用に供給され、 前記負荷抵抗で発 生する電圧値を、 周波数値に変換する電圧周波数変換手段と、  A voltage-frequency converter for supplying a discharge current from the charging / discharging unit for operating power, and converting a voltage value generated by the load resistance into a frequency value;
前記充放電手段からの放電電流が動作電力用に供給され、 前記電圧周波数変 換手段から出力される計測信号を外部に伝送する伝送手段と、  A transmission means for supplying a discharge current from the charge / discharge means for operating power, and transmitting a measurement signal output from the voltage frequency conversion means to the outside;
を有することを特徴とする交流電流計測装置。  An alternating current measuring device comprising:
2. 前記充放電制御手段は、 前記二次電流で生成される電圧が所定値より高くな ると電流が流れるッヱナ一ダイオー ドと、 そのッヱナ一ダイオー ドに電流が 流れると、 前記二次電流で生成される電圧を飽和電圧まで下げるサイリスタ と、 そのサイ リスタに前記充放電手段からの放電電流が逆流するのを防止す る逆流防止用ダイォ一ドと、 を有することを特徴とする請求項 1に記載の交流 電流計測装置。 2. The charging / discharging control means includes: a diode through which current flows when a voltage generated by the secondary current becomes higher than a predetermined value; and a secondary current by flowing current through the diode. A thyristor that reduces the voltage generated in step (b) to a saturation voltage, and a backflow prevention diode that prevents the discharge current from the charging / discharging means from flowing back into the thyristor. 2. The AC current measurement device according to 1.
3. 前記充放電手段からの放電電流によって生成される電圧が設定された動作 停止電圧値より低くなると放電電流の供給を停止させ、 設定された動作開始 電圧値より高くなると放電電流の供給を開始するように切り換える切換手段 を、 さらに有することを特徴とする請求項 1又は 2に記載の交流電流計測装 3. When the voltage generated by the discharge current from the charging / discharging means becomes lower than the set operation stop voltage value, the supply of the discharge current is stopped, and when the voltage becomes higher than the set operation start voltage value, the supply of the discharge current is started. 3. The alternating current measurement device according to claim 1, further comprising: a switching unit configured to perform switching.
4. 前記整流手段は、 前記二次電流を全波整流することを特徴とする請求項 1乃 至 3のいずれか 1つの項に記載の交流電流計測装置。 4. The rectifier, wherein the secondary current is full-wave rectified. The alternating current measurement device according to any one of the items from 3 to 3.
5. 前記整流手段は、 前記二次電流を半波整流することを特徴とする請求項 1乃 至 3のいずれか 1つの項に記載の交流電流計測装置。 5. The alternating current measurement device according to claim 1, wherein the rectification unit performs half-wave rectification on the secondary current.
PCT/JP1999/000565 1998-02-12 1999-02-10 Instrument for measuring alternating current WO1999041618A1 (en)

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