WO1999009421A1 - Dispositif de controle de courant - Google Patents

Dispositif de controle de courant Download PDF

Info

Publication number
WO1999009421A1
WO1999009421A1 PCT/GB1998/002480 GB9802480W WO9909421A1 WO 1999009421 A1 WO1999009421 A1 WO 1999009421A1 GB 9802480 W GB9802480 W GB 9802480W WO 9909421 A1 WO9909421 A1 WO 9909421A1
Authority
WO
WIPO (PCT)
Prior art keywords
electrically conductive
conductive element
temperature
current
potential difference
Prior art date
Application number
PCT/GB1998/002480
Other languages
English (en)
Inventor
Roger Francis Golder
Christopher Davies
Original Assignee
Cambridge Consultants 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 Cambridge Consultants Limited filed Critical Cambridge Consultants Limited
Publication of WO1999009421A1 publication Critical patent/WO1999009421A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
    • G01R1/20—Modifications of basic electric elements for use in electric measuring instruments; Structural combinations of such elements with such instruments
    • G01R1/203—Resistors used for electric measuring, e.g. decade resistors standards, resistors for comparators, series resistors, shunts
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
    • G01R1/44—Modifications of instruments for temperature compensation
    • 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
    • G01R19/0092—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring current only
    • 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

Definitions

  • the invention relates to a current monitoring device, for example for inclusion in an electricity meter.
  • Typical devices for monitoring the magnitude of a flowing electric current include the use of a low value resistor to create a voltage proportional to line current.
  • the problem with this approach is the sensitivity of such low value resistors to temperature with the result that they undergo significant changes in their resistive characteristics with temperature changes brought about by changes in ambient temperature and self-heating effects.
  • materials which have a zero temperature coefficient such as Nicrome or Manganin.
  • these materials are expensive and not ideally suited for use in commercial, mass produced products such as electricity meters.
  • a current monitoring device comprises an electrically conductive element through which a current to be monitored passes in use; a voltage sensor for determining the potential difference between two points on the electrically conductive element; a temperature sensor for monitoring the temperature of the electrically conductive element; and a current processor for determining a value, related to the current flowing through the electrically conductive element, in accordance with a predetermined algorithm based on the determined potential difference and the monitored temperature so as to compensate for variations in the determined potential difference with temperature.
  • the invention accepts that there will be a variation in electrical performance of the electrically conductive element with temperature and deals with this by compensating for that variation by monitoring the temperature of the element.
  • the temperature of the element could be monitored at a number of positions along its length, it has been found sufficient to monitor the element at just one location along the element, typically centrally between the two points between which the potential difference is determined.
  • An important aspect of the invention is the manner in which the temperature sensor is provided. Although such a sensor could be provided in a variety of ways, in the preferred approach, the temperature sensor is provided on a semiconductor chip secured in heat conducting contact with the electrically conductive element. This approach is convenient since the position of the temperature sensor on the semiconductor chip is not important. The whole chip will take the temperature of the electrically conductive element . Conveniently, the semiconductor chip also includes the voltage sensor. This reduces the complexity of the device and results in a compact construction.
  • the electrically conductive element can comprise any convenient material but in the preferred approach comprises copper, for example in the form of a copper bar.
  • the electrically conductive element is substantially symmetrical about the temperature sensing position and between said two points.
  • a current monitoring device comprises an electrically conductive element through which a current to be monitored flows in use; a voltage sensor for determining the potential difference between two points on the electrically conductive element; and a current processor for determining a value, relating to the current flowing through the electrically conductive element, in accordance with a predetermined algorithm based on the determined potential difference, wherein the voltage sensor is coupled to the two points on the electrically conductive element via leads which extend at least partly within sections of the electrically conductive element so as to reduce inductive effects on the leads.
  • the electrically conductive element may be tubular, for example cylindrical, with the leads extending through the tubular element while in others the electrically conductive element may comprise a pair of spaced bars between which the leads extend.
  • a further problem that can arise with these devices is long term stability.
  • the conductivity of metals is dependent on the crystal size which may in turn be affected by its state of "working" or annealing.
  • the electrically conductive element has been pre-worked so as to have an anneal state substantially matching its end of life anneal state.
  • the current monitoring device can be used simply to monitor current but the device is particularly useful in an electricity power meter for monitoring the use of electrical power supplied along dual lines, the meter further comprising a voltage monitor for monitoring the potential difference between the two lines; and a power processor for computing power from the monitored current and potential difference.
  • the temperature sensor and voltage sensor are provided on a semiconductor chip
  • the voltage monitor and/or the power processor are also mounted on the same chip.
  • the current and power processors are implemented by the same processor.
  • Figure 1 is a schematic, perspective view of part of the meter
  • Figure 2 is an exploded view of the components shown in Figure 1 ;
  • Figure 3 is a section taken along the line 3-3 in Figure 1 ;
  • Figure 4 is a section taken along the line 4-4 in Figure 1 ;
  • Figure 5 is a block circuit diagram of the meter.
  • Figure 6 shows temperature profiles for a lOO ⁇ Cu bar carrying 100A.
  • the electronic power meter shown in the drawings is suitable as a Class 2 meter and comprises a printed circuit board (PCB) 1 which carries an integrated circuit, semiconductor chip 2 on one surface and adjacent an edge.
  • PCB printed circuit board
  • the PCB 1 has typical dimensions 80mm x 45mm.
  • the PCB 1 and chip 2 are sandwiched between a pair of legs 4A,4B of a U-shaped stamped copper bar 3, the bar being riveted at each end to respective terminals 5,6.
  • Each terminal 5,6 has a pair of screws 7 to enable the terminal to be connected to a respective part of a live line 8 carrying, along with neutral line 9, an AC current ( Figure 5) .
  • the components connecting the chip 2 to the neutral line 9 are not shown in Figures 1 and 2.
  • the components carried on the chip 2 can be seen in Figure 5. These components comprise a central processor 10 connected to memory 11 for storing programme instructions and also to an EEPROM 12 mounted on the PCB 1 which stores calibration information.
  • the central processor 10 is connected via an A to D convertor 13 to a line current conditioning amplifier 14 coupled via leads 25,26 on the PCB to two contact points 27,28 on the copper bar 3.
  • the amplifier 14 amplifies the monitored voltage drop by for example 16 to 32 times and has a temperature stable gain to at least 30ppm/°C.
  • the central processor 10 monitors the amplified voltage drop (V bar ) between the contact points 27,28 in order to determine the current flowing along the line 8, as will be described in more detail below.
  • the central processor 10 is also connected via an A to D convertor 15 to a line voltage conditioning amplifier 16 via respective resistor and capacitor pairs 17A, 17B and 18A,18B. This enables the central processor 10 to determine the voltage drop (V line ) across the lines 8,9.
  • a temperature sensitive device 19 is mounted on the chip 2 to monitor the temperature of the chip, the output from the device being fed via an A to D convertor 20 to the central processor 10.
  • the device 19 may have any conventional form including any type of Si junction such as a diode or transistor, a polysilicon material whose resistance varies with temperature or an FET.
  • Figure 6 shows the temperature profiles, above ambient, to be expected from a simple copper bar or shunt of lOO ⁇ resistance connected between the live terminal blocks 5,6.
  • the length of 60mm is determined in this example by the distance between the live terminals of a standard UK Class 2 domestic electricity meter.
  • the copper bar 3 has a substantially symmetrical form on either side of the temperature sensing point defined by the chip
  • the processor is connected to a real time clock circuit 21 and a system clock 22 while power, derived from the lines 8,9 is fed to conventional power generation circuitry 23.
  • Information generated by the central processor 10 is fed to an LCD display 24 or the like.
  • the meter components can all be housed in a casing, with suitable windows to allow the display 24 to be visible, having dimensions in the order 125mm x 100mm x
  • the material of the chip takes up the temperature of the adjacent portion of the bar 3.
  • the transistor 19 which monitors the temperature of the chip will effectively monitor the temperature of the bar
  • This function f n may be implemented as a look-up table or as a mathematical formula. Such a formula would typically be
  • the processor determines electrical energy passed through the meter (E) as follows:
  • Energy usage can then be displayed via the display 24 and stored in the EEPROM 12.
  • the leads 24,25 which will be in the form of printed tracks on the PCB 1, extend substantially completely between the legs 4A,4B of the copper bar 3.
  • the reason for this is to minimise or at least reduce inductive effects on currents passing through the leads 24,25.
  • the copper bar 3 may be in the form of a tube such as a cylinder in which case the leads again would pass wholly within the cylinder.
  • the copper bar 3 is pre- worked so as to take up an anneal state which corresponds to that to be expected at the end of its working life. This increases the long term stability of the copper bar.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)

Abstract

La présente invention concerne un dispositif de contrôle de courant comprenant un élément électroconducteur (3) à travers lequel passe un courant devant être surveillé. Un voltmètre (10) détermine la différence de potentiel entre deux points sur l'élément électroconducteur (3). Par ailleurs, un capteur thermique (19) surveille la température de cet élément. Un processeur de courant (10) détermine une valeur se rapportant au courant traversant l'élément précité (3). Il utilise pour cela un algorithme prédéterminé prenant en compte la différence de potentiel mesurée et la température détectée, et ce de façon à corriger les variations de la différence de potentiel calculée en fonction de la température.
PCT/GB1998/002480 1997-08-20 1998-08-19 Dispositif de controle de courant WO1999009421A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9717667.1 1997-08-20
GBGB9717667.1A GB9717667D0 (en) 1997-08-20 1997-08-20 Current monitoring device

Publications (1)

Publication Number Publication Date
WO1999009421A1 true WO1999009421A1 (fr) 1999-02-25

Family

ID=10817790

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1998/002480 WO1999009421A1 (fr) 1997-08-20 1998-08-19 Dispositif de controle de courant

Country Status (2)

Country Link
GB (1) GB9717667D0 (fr)
WO (1) WO1999009421A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1247304A4 (fr) * 1999-10-28 2008-03-26 Microchip Tech Inc Dispositif a resistance en derivation pour controler l'etat de charge d'une batterie
WO2009003395A1 (fr) * 2007-06-29 2009-01-08 Wei Wu Dispositif et procédé de mesure de courant et de température en ligne à grande plage et grande précision
EP2042879A1 (fr) * 2007-09-28 2009-04-01 MAGNETI MARELLI SISTEMI ELETTRONICI S.p.A. Capteur de courant de batterie pour véhicule automobile
WO2016015842A1 (fr) * 2014-08-01 2016-02-04 Isabellenhütte Heusler Gmbh & Co. Kg Résistance, en particulier résistance de mesure de courant faiblement ohmique
EP3570046A1 (fr) * 2018-05-18 2019-11-20 ABB Schweiz AG Bloc terminal pour la mesure du courant et procédés associés

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0161447A1 (fr) * 1984-04-17 1985-11-21 Fr. Sauter AG Fabrik elektr. Apparate Compteur électronique de consommation d'énergie électrique
US5420504A (en) * 1993-07-06 1995-05-30 General Electric Company Noninductive shunt current sensor based on concentric-pipe geometry
WO1996018109A2 (fr) * 1994-12-09 1996-06-13 National Semiconductor Corporation Resistance integree permettant de detecter des parametres electriques
EP0727669A2 (fr) * 1995-02-17 1996-08-21 Landis & Gyr Technology Innovation AG Dispositif de compensation de température

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0161447A1 (fr) * 1984-04-17 1985-11-21 Fr. Sauter AG Fabrik elektr. Apparate Compteur électronique de consommation d'énergie électrique
US5420504A (en) * 1993-07-06 1995-05-30 General Electric Company Noninductive shunt current sensor based on concentric-pipe geometry
WO1996018109A2 (fr) * 1994-12-09 1996-06-13 National Semiconductor Corporation Resistance integree permettant de detecter des parametres electriques
EP0727669A2 (fr) * 1995-02-17 1996-08-21 Landis & Gyr Technology Innovation AG Dispositif de compensation de température

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1247304A4 (fr) * 1999-10-28 2008-03-26 Microchip Tech Inc Dispositif a resistance en derivation pour controler l'etat de charge d'une batterie
WO2009003395A1 (fr) * 2007-06-29 2009-01-08 Wei Wu Dispositif et procédé de mesure de courant et de température en ligne à grande plage et grande précision
EP2042879A1 (fr) * 2007-09-28 2009-04-01 MAGNETI MARELLI SISTEMI ELETTRONICI S.p.A. Capteur de courant de batterie pour véhicule automobile
WO2016015842A1 (fr) * 2014-08-01 2016-02-04 Isabellenhütte Heusler Gmbh & Co. Kg Résistance, en particulier résistance de mesure de courant faiblement ohmique
CN106574939A (zh) * 2014-08-01 2017-04-19 伊莎贝尔努特·霍伊斯勒两合公司 电阻、特别是较低电阻值的电流测量电阻
US10161966B2 (en) 2014-08-01 2018-12-25 Isabellenhuette Heusler Gmbh & Co. Kg Resistor, in particular low-resistance current measuring resistor
EP3570046A1 (fr) * 2018-05-18 2019-11-20 ABB Schweiz AG Bloc terminal pour la mesure du courant et procédés associés
CN110501558A (zh) * 2018-05-18 2019-11-26 Abb瑞士股份有限公司 用于电流测量的端子块以及相关方法
US11300592B2 (en) 2018-05-18 2022-04-12 Hitachi Energy Switzerland Ag Terminal block for current measurement and related methods
CN110501558B (zh) * 2018-05-18 2024-07-05 日立能源有限公司 用于电流测量的端子块以及相关方法

Also Published As

Publication number Publication date
GB9717667D0 (en) 1997-10-29

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