WO1991011725A1 - Multiplicateur instantane pour systemes de mesure d'energie - Google Patents

Multiplicateur instantane pour systemes de mesure d'energie Download PDF

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Publication number
WO1991011725A1
WO1991011725A1 PCT/GB1990/000134 GB9000134W WO9111725A1 WO 1991011725 A1 WO1991011725 A1 WO 1991011725A1 GB 9000134 W GB9000134 W GB 9000134W WO 9111725 A1 WO9111725 A1 WO 9111725A1
Authority
WO
WIPO (PCT)
Prior art keywords
instantaneous
voltage
output
multiplier
amplifier
Prior art date
Application number
PCT/GB1990/000134
Other languages
English (en)
Inventor
Andrew John Wilks
Original Assignee
Omega Electric Limited
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 Omega Electric Limited filed Critical Omega Electric Limited
Publication of WO1991011725A1 publication Critical patent/WO1991011725A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R21/00—Arrangements for measuring electric power or power factor
    • G01R21/133—Arrangements for measuring electric power or power factor by using digital technique
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06J—HYBRID COMPUTING ARRANGEMENTS
    • G06J1/00—Hybrid computing arrangements

Definitions

  • This invention relates to an instantaneous multiplier for use in power measurement systems such as solid state electricity meters.
  • Solid state electricity meters generally require a four quadrant multiplier to compute the actual power waveform with varying voltage, current and power factor of the load. This is generally achieved using a four quadrant multiplier based upon the variable transconductance principle. Unfortunately such four quadrant multipliers suffer from drift problems and linearity errors.
  • an instantaneous multiplier for electrical power meters incorporating a variable resistance network within an amplifier circuit, said variable resistance network being designed to vary with the magnitude of the rectified voltage on an instantaneous basis, an input to the resistance network for receipt of a signal representative of the instantaneous AC current and a phase comparator controlling a changeover switch at the amplified output of the resistance network to correct for loss of phase information in the voltage due to rectification.
  • the multiplier will use an analogue to digital convertor connected to the input of a digitally programmable resistor network as the resistance network to vary the resistance within the amplifier circuit.
  • the analogue to digital convertor will preferably incorporate a further digitally programmable resistance network whose output is compared continuously with the rectified voltage level and is modified to track that voltage.
  • Figure 2 is a block diagram of the full instantaneous multiplier circuit; and Figure 3 is a similar block diagram of an alternative form of multiplier circuit.
  • a full wave rectified voltage waveform is applied to a non-inverting input of a comparator 2. If the rectified signal input is lower than the other input then the comparator output will be a '0' and the output of a de ⁇ glitching clocked latch 3 will be a 'O 1 also. This causes
  • the inverting operational amplifier 5 then produces an output which is applied to the inverting input of the comparator 2.
  • This sequence of events will continue until the voltage at the inverting input of the comparator 2 is more negative than at the non-inverting input, causing the comparator 2 to change state at its output, which is propagated through the latch 3, causing the counter 4 to count down.
  • the current flowing into the summing junction of the operational amplifier 5 will thus decrease causing the voltage at the inverting input of the comparator 2 to fall, which may produce a change of state of the comparator 2.
  • the overall action is that the voltage at the inverting input of the comparator 2 will closely track the voltage at the non-inverting input.
  • the oscillator 8 always produces a count up or count down in the counter 4, and an invertor 9 ensures that the count up or down occurs at a defined time after the previous count, to overcome oscillation at the output of the comparator 2 due to the two inputs being at similar potentials.
  • the oscillator rate is generally faster than that required as a miniumum to track the full-wave rectified waveform so that the re-constituted waveform at the inverting input of the
  • SUBSTITUTE SHEET comparator 2 hunts' about the waveform on the non-inverting input, effectively increasing the resolution of the 8-bit convertor of the voltage envelope.
  • the instantaneous AC voltage v is applied to a full-wave rectifier 10 and a phase detector 11.
  • the output of the full-wave rectifier is applied to the analogue to digital convertor 1 and the output of this is in turn applied to a digitally programmable binary resistor network 12 such as an R-2R network.
  • a digitally programmable binary resistor network 12 such as an R-2R network.
  • the digitally programmable resistor network 17 of Figure 3 could be used. This comprises a number of analogue switches 18 and a weighted resistor network 19.
  • a voltage signal representative of the instantaneous AC current i is applied to the digitally programmable binary resistor network 12.
  • the output of the amplifier 13 will be the resultant of instantaneous current multiplied by the rectified value of the applied voltage by virtue of the input resistance to the amplifier 13 being made to vary with the rectified value of the applied voltage.
  • phase detector 11 In order to calculate correctly the active power supplied to a load the phase of the applied voltage is determined by a phase detector 11. This detection of the sign of the applied voltage effectively is a doubling in resolution of the A to D convertor section 1 of the scheme. The phase detector 11 then operates an analogue changeover switch 14 so that the output of the amplifier 13 is inverted

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Mathematical Physics (AREA)
  • Automation & Control Theory (AREA)
  • Evolutionary Computation (AREA)
  • Fuzzy Systems (AREA)
  • Software Systems (AREA)
  • Power Engineering (AREA)
  • Measurement Of Current Or Voltage (AREA)

Abstract

Une tension instantanée de courant alternatif v est appliquée à un redresseur pleine onde (10) et à un détecteur de phases (11). La sortie du redresseur pleine onde est appliquée à un convertisseur analogique/numérique (1) et la sortie de celui-ci est appliquée à un réseau à résistances binaires numériquement programmable (12), par exemple un réseau R-2R. Un signal de tension qui représente le courant c.a. instantané i est appliqué au réseau de résistances binaires numériquement programmable (12). Par conséquent, la sortie de l'amplificateur (13) sera la résultante du courant instantané multiplié par la valeur redressée de la tension appliquée, puisque la résistance d'entrée à l'amplificateur (13) est modifiée en fonction de la valeur de la tension appliquée. La phase de la tension appliquée est déterminée par un détecteur de phases (11) qui actionne un commutateur analogique (14), de sorte que la sortie de l'amplificateur (13) est inversée par un amplificateur (15) pour des excursions négatives de la tension instantanée v. Par conséquent, la sortie d'un amplificateur de totalisation (16) sera une représentation vraie de l'énergie instantanée.
PCT/GB1990/000134 1988-07-26 1990-01-30 Multiplicateur instantane pour systemes de mesure d'energie WO1991011725A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB8817714A GB2221313B (en) 1988-07-26 1988-07-26 Instantaneous multiplier for use in power measurement systems

Publications (1)

Publication Number Publication Date
WO1991011725A1 true WO1991011725A1 (fr) 1991-08-08

Family

ID=10641079

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1990/000134 WO1991011725A1 (fr) 1988-07-26 1990-01-30 Multiplicateur instantane pour systemes de mesure d'energie

Country Status (2)

Country Link
GB (1) GB2221313B (fr)
WO (1) WO1991011725A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2686994B1 (fr) * 1992-02-04 1997-01-17 Sagem Compteur electronique de concommation d'energie electrique.
FR2702581B1 (fr) * 1993-03-12 1995-06-02 Sagem Circuit multiplicateur à potentiomètres et compteur d'énergie électrique incorporant un tel circuit.

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4058768A (en) * 1977-01-07 1977-11-15 General Electric Company Two-way electronic kWh meter
US4079313A (en) * 1977-04-18 1978-03-14 Allen-Bradley Company Digital watts transducer
EP0008630A1 (fr) * 1978-07-17 1980-03-19 Siemens Aktiengesellschaft Convertisseur puissance/fréquence avec un microprocesseur
EP0104999A2 (fr) * 1982-09-24 1984-04-04 Sangamo Weston, Inc. Dispositif pour changer de gain, avec erreur diminuée, pour un wattmètre
US4535287A (en) * 1983-03-25 1985-08-13 General Electric Company Electronic watt/watthour meter with automatic error correction and high frequency digital output
EP0265172A1 (fr) * 1986-10-17 1988-04-27 THE GENERAL ELECTRIC COMPANY, p.l.c. Appareil de mesure pour puissance électrique
US4795974A (en) * 1987-07-24 1989-01-03 Ford Motor Company Digital energy meter
US4837504A (en) * 1985-05-02 1989-06-06 Zellweger Uster Ltd. Electricity meter and method of calibrating same

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4101966A (en) * 1977-03-28 1978-07-18 Communications Satellite Corporation 4-quadrant multiplier

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4058768A (en) * 1977-01-07 1977-11-15 General Electric Company Two-way electronic kWh meter
US4079313A (en) * 1977-04-18 1978-03-14 Allen-Bradley Company Digital watts transducer
EP0008630A1 (fr) * 1978-07-17 1980-03-19 Siemens Aktiengesellschaft Convertisseur puissance/fréquence avec un microprocesseur
EP0104999A2 (fr) * 1982-09-24 1984-04-04 Sangamo Weston, Inc. Dispositif pour changer de gain, avec erreur diminuée, pour un wattmètre
US4535287A (en) * 1983-03-25 1985-08-13 General Electric Company Electronic watt/watthour meter with automatic error correction and high frequency digital output
US4837504A (en) * 1985-05-02 1989-06-06 Zellweger Uster Ltd. Electricity meter and method of calibrating same
EP0265172A1 (fr) * 1986-10-17 1988-04-27 THE GENERAL ELECTRIC COMPANY, p.l.c. Appareil de mesure pour puissance électrique
EP0267693A1 (fr) * 1986-10-17 1988-05-18 THE GENERAL ELECTRIC COMPANY, p.l.c. Appareil de mesure pour puissance électrique
US4795974A (en) * 1987-07-24 1989-01-03 Ford Motor Company Digital energy meter

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Patent Abstracts of Japan, Vol 12, No 8, P654, abstract of JP 62-169061, publ 1987-07-25 *

Also Published As

Publication number Publication date
GB8817714D0 (en) 1988-09-01
GB2221313A (en) 1990-01-31
GB2221313B (en) 1993-02-24

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