WO1996028739A1 - Electricity measurement apparatus - Google Patents
Electricity measurement apparatus Download PDFInfo
- Publication number
- WO1996028739A1 WO1996028739A1 PCT/GB1996/000539 GB9600539W WO9628739A1 WO 1996028739 A1 WO1996028739 A1 WO 1996028739A1 GB 9600539 W GB9600539 W GB 9600539W WO 9628739 A1 WO9628739 A1 WO 9628739A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- sensor
- electricity
- output signal
- measurement apparatus
- signal
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R21/00—Arrangements for measuring electric power or power factor
- G01R21/08—Arrangements for measuring electric power or power factor by using galvanomagnetic-effect devices, e.g. Hall-effect devices
Definitions
- the present invention relates to an electricity measurement apparatus and a method of electricity measurement, in particular for current measurement, power measurement and Watthour metering.
- I is the total current
- A is the cross sectional area of the conductor.
- This value l A is the current density J.
- the sensor output signal has a voltage. VH. which is proportional to the magnetic field strength B at the sensor, and a bias current IB flowing through the sensor as follows:
- VH S x B x IB (Equation 2).
- the proportionality coefficient S is the sensitivity of the sensor. By keeping constant the current through the Hall sensor, a linear relationship is achieved between the detected
- Hall sensors produce Direct Current (D.C.) offset errors, which are independent of the direction (positive or negative) with which the bias current IB is applied to the sensor.
- the bias current IB is selected to be proportional to the electricity mains supply voltage.
- the current IB and detected magnetic field B are both Alternating Current (A.C.) signals which vary according to a sine relation. Accordingly, the output voltage VH follows a sine squared relation where D.C. offsets are components of the resultant VH signal.
- D.C. offsets can also occur due to the electronic circuits associated with the subsequent processing operations.
- the present invention preferably proudes an electrical measurement apparatus comprising supply means operative to supply a rectified A.C. supply signal to a sensor, the sensor being operative to detect magnetic field strength due to A.C. current flow along a conductor and to provide an output signal dependent on detected field strength and the rectified A C supply signal, the output signal following a sine-squared relation with alternating positive and negative sign in each half cycle, and filtering means operative to remove a component due to a D.C. offset error from the output signal
- the rectified A.C. signal is preferably a rectified A.C. bias current signal
- the filtering means preferably comprises a capacitor
- the A.C mains signal is the alternating voltage signal of an electrical supply netwoik to which the conductor is connected.
- the senor is a Hall sensor and the supply signal to the sensor is a current signal
- the supply signal is preferably proportional to the electricity mains supply voltage
- the output signal from a sensor is preferably a voltage signal
- the A C current flow along the conductor is preferably an electricity mains supply current
- the present invention also provides a method of measuring electricity flow along a conductor
- BAD ORIGINAL J> including the steps of supplying a rectified A.C. supply signal to a sensor, the sensor detecting magnetic field strength due to A.C. current flow along a conductor and providing an output signal dependent on detected field strength and the rectified A.C. supply signal, the output signal following a sine-squared relation with alternating positive and negative sign in each half cycle, and filtering to remove a component due to D.C. offset error from the output signal.
- Figure 1 is a circuit diagram for an embodiment of the invention.
- Figure 2 shows wave forms for supply current and output Hall ⁇ oltage in a circuit according to the present invention.
- Figure 3 shows corresponding wave forms to Figure 2 for a typical known circuit (prior art) for comparison.
- this invention relates to apparatus and a method for eliminating D.C. voltage offset errors in a multiplying circuit used in an energy measurement circuit.
- the preferred method of energy measurement is based on the alternating current flow to be measured producing an alternating magnetic field B. that field being detected using an electronic circuit containing an Hall effect device.
- the A.Créage to be measured is convened to a Hall bias current IB and applied across the Hall effect device.
- the resulting Hall voltage VH is
- Figure 1 shows a schematic of a circuit capable of producing an instantaneous Hall bias current. IB. of amplitude proportional to the instantaneous A.C. voltage applied to the input port A.
- the circuit is arranged to produce an instantaneous Hall bias current which is in phase with the applied A.C. voltage during the positive half cycle of the A.C. voltage, and is 180 degrees out of phase with the applied A.C. voltage during the negative half cycle of the applied A.C. voltage.
- VH A Sin : 0 for 0 in the range 0 to ⁇
- this waveform can be expressed as:
- VH A S ⁇ n : 0 V0 ⁇ [0. ⁇ )
- V means "for all values of” ⁇ means "is in the range”
- V0 ⁇ [0. ⁇ ” signifies "for all values of 0 in the interval from and including 0 up to but not including ⁇ ".
- the instantaneous amplitude of this alternating S ⁇ n : 0 voltage w aveform is proportional to the multiplication of the instantaneous amplitude of the alternating magnetic field B and the Hall bias current IB. Since the Hall bias current IB is proportional to the A C ⁇ oltage applied to the input port A and the alternating magnetic field B is proportional to the alternating current flow through the conductor, the amplitude of the alternating S ⁇ n ⁇ 0 Hall ⁇ oltage waveform.
- the production of the alternating S ⁇ n : 0 Hall voltage waveform VH allows simple elimination of any unwanted D C voltages in the circuit by filtering out D C voltages using ⁇ D.C blocking capacitor. Unwanted D.C voltages can occur due to Hall effect device D.C offsets and amplifier D.C. offsets D C voltages on the Hall voltage VH can also be caused by external D.C. magnetic fields All of these D.C voltages are simply removed by using a simple D.C. blocking capacitor.
- the circuit shown in figure 1 also centres the alternating Sin : 0 Hall voltage waveform. VH, on Vref allowing the Hall effect device to be operated in its linear region.
- VDD is the positive circuit supply voltage typically 5VoltsDC.
- VSS is the negative circuit supply voltage typically OVoltsDC and Vref is typically the voltage midpoint between these, typically 2.5VoltsDC.
- the approach is to generate ⁇ Hall bias current IB proportional to the applied A.C voltage in two different ways for each of the two half cycles of the A.C voltage applied to input A
- the A.C voltage is applied to the input A of resistor RA r
- bias current is created with the same polarity as du ⁇ ng the negative half cycle. This is achieved by Resistor RA, and Transistors M2A and M2B. A bias current IB2 is generated and flows through transistor M2B which matches the current flowing through RA and transistor M2A. This matching is achieved since transistor M2A and M2B are arranged in what is commonly known as a "current mirror' There is a small error in this second half cycle of the A.C. voltage to Hall bias current conversion since transistor M2A fails to operate below around 2VoltsDC. This is compensated for by amplifier A2. transistor M5 and resistor RB which create the bias current IBerr during this inoperative region. The resistance value of resistor RB is essentially the same as the resistance value of resistor RA.
- the circuit has created the desired rectified Hall bias current IB.
- the econd half of the circuit using transistors K.M 1 , K.M2, M4A. M4B. K.M3/2 and M3 is included to centre the Hall voltage VH on Vref.
- the Hall voltage is maintained such that the midpoint of its amplitude takes the midpoint value between maximum possible output voltage VDD and minimum possible output ⁇ oltage VSS of the Hall device.
- Vref is 2.5V D.C. where the maximum possible Hall voltage output is 5V and the minimum is OV
- the Hall voltage thus varies around its midpoint output where the response of the Hall device is most linear.
- the Hall voltage is centred on Vref by careful control of the current into the Hall device
- the Hall bias current IB flows through M3 from the supplv VDD, through the Hall device and becomes either IB 1. IB2 or IBerr.
- the centre voltage of the Hall device can however be varied by changing the impedance of transistor M3
- the input to control this voltage Vref is at M4B
- Transistors M4A and M4B are arranged as a Long Tailed Pair le. with their emitters connected to ⁇ current source.
- the current source is generated by transistors K.M 1 and K.M2. This current source is proportional to the Hall bias currents IB 1 and IB2 since the same control signals are input to K.M 1 and K.M2 as M l and M2A.
- Transistors K.M3/2 and M3 are arranged as a "current mirror", with current IM 1 flowing through K.M3/2 being mirrored through M3.
- the factor K is typically 1/10 vvhich helps reduce the overall current consumption of the circuit.
Abstract
Description
Claims
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT96904978T ATE217090T1 (en) | 1995-03-16 | 1996-03-08 | ELECTRICITY MEASUREMENT APPARATUS |
AU48881/96A AU702196B2 (en) | 1995-03-16 | 1996-03-08 | Electricity measurement apparatus |
US08/913,500 US6037763A (en) | 1995-03-16 | 1996-03-08 | Electricity measurement apparatus using hall effect sensor having rectified bias current |
EP96904978A EP0879419B1 (en) | 1995-03-16 | 1996-03-08 | Electricity measurement apparatus |
DE69621047T DE69621047T2 (en) | 1995-03-16 | 1996-03-08 | ELECTRICITY MEASURING DEVICE |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GBGB9505314.6A GB9505314D0 (en) | 1995-03-16 | 1995-03-16 | Electricity measurement apparatus |
GB9505314.6 | 1995-03-16 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1996028739A1 true WO1996028739A1 (en) | 1996-09-19 |
Family
ID=10771311
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB1996/000539 WO1996028739A1 (en) | 1995-03-16 | 1996-03-08 | Electricity measurement apparatus |
Country Status (9)
Country | Link |
---|---|
US (1) | US6037763A (en) |
EP (1) | EP0879419B1 (en) |
AT (1) | ATE217090T1 (en) |
AU (1) | AU702196B2 (en) |
DE (1) | DE69621047T2 (en) |
GB (1) | GB9505314D0 (en) |
IN (1) | IN187455B (en) |
WO (1) | WO1996028739A1 (en) |
ZA (1) | ZA962127B (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2000062084A1 (en) * | 1999-04-12 | 2000-10-19 | Chk Wireless Technologies Australia Pty Limited | Apparatus and method for electrical measurements on conductors |
CN112834812A (en) * | 2021-01-06 | 2021-05-25 | 南京能晶电子科技有限公司 | Hall current sensor chip with strong anti-interference capability |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6828770B1 (en) * | 1999-04-12 | 2004-12-07 | Chk Wireless Technologies Australia Pty Ltd. | Apparatus and method for electrical measurements on conductors |
DE10224747B4 (en) * | 2002-06-04 | 2004-05-13 | Infineon Technologies Ag | Sensor circuit and method for manufacturing the same |
WO2004105638A2 (en) * | 2003-05-27 | 2004-12-09 | Spinalmotion, Inc. | Prosthetic disc for intervertebral insertion |
US8963535B1 (en) * | 2009-06-30 | 2015-02-24 | Cirrus Logic, Inc. | Switch controlled current sensing using a hall effect sensor |
WO2012015890A1 (en) * | 2010-07-27 | 2012-02-02 | Georgia Tech Research Corporation | Systems and methods for determining current flow through a utility asset |
WO2015141235A1 (en) * | 2014-03-20 | 2015-09-24 | 公立大学法人大阪市立大学 | Power sensor, power sensor system, and regenerated power detection device |
CN106526313B (en) * | 2016-12-05 | 2019-05-28 | 威胜信息技术股份有限公司 | A kind of DC measurement method |
KR20220022284A (en) * | 2020-08-18 | 2022-02-25 | 삼성전기주식회사 | Apparatus for reducing offset of hall sensor and apparatus for controlling lens module |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1010156B (en) * | 1954-03-08 | 1957-06-13 | Siemens Ag | Apparent consumption measuring arrangement, especially counter, for three-phase current |
DE1209653B (en) * | 1961-09-14 | 1966-01-27 | Siemens Ag | Apparent consumption measuring device with a Hall generator |
EP0601817A1 (en) * | 1992-12-11 | 1994-06-15 | Kabushiki Kaisha Toshiba | Power multiplication circuit |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5793263A (en) * | 1980-11-29 | 1982-06-10 | Toshiba Corp | Watt-hour meter employing hall element |
JPH0726978B2 (en) * | 1988-09-22 | 1995-03-29 | 東洋通信機株式会社 | Current sensor circuit |
JP3142994B2 (en) * | 1993-07-21 | 2001-03-07 | 株式会社東芝 | Power calculation device |
JP3081751B2 (en) * | 1994-03-03 | 2000-08-28 | 株式会社東芝 | Electric quantity measuring device |
-
1995
- 1995-03-16 GB GBGB9505314.6A patent/GB9505314D0/en active Pending
-
1996
- 1996-03-08 DE DE69621047T patent/DE69621047T2/en not_active Expired - Fee Related
- 1996-03-08 US US08/913,500 patent/US6037763A/en not_active Expired - Fee Related
- 1996-03-08 AU AU48881/96A patent/AU702196B2/en not_active Ceased
- 1996-03-08 WO PCT/GB1996/000539 patent/WO1996028739A1/en active IP Right Grant
- 1996-03-08 IN IN420CA1996 patent/IN187455B/en unknown
- 1996-03-08 EP EP96904978A patent/EP0879419B1/en not_active Expired - Lifetime
- 1996-03-08 AT AT96904978T patent/ATE217090T1/en not_active IP Right Cessation
- 1996-03-15 ZA ZA9602127A patent/ZA962127B/en unknown
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1010156B (en) * | 1954-03-08 | 1957-06-13 | Siemens Ag | Apparent consumption measuring arrangement, especially counter, for three-phase current |
DE1209653B (en) * | 1961-09-14 | 1966-01-27 | Siemens Ag | Apparent consumption measuring device with a Hall generator |
EP0601817A1 (en) * | 1992-12-11 | 1994-06-15 | Kabushiki Kaisha Toshiba | Power multiplication circuit |
Non-Patent Citations (1)
Title |
---|
PATENT ABSTRACTS OF JAPAN vol. 6, no. 175 (P - 141)<1053> 9 September 1982 (1982-09-09) * |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2000062084A1 (en) * | 1999-04-12 | 2000-10-19 | Chk Wireless Technologies Australia Pty Limited | Apparatus and method for electrical measurements on conductors |
AU766435B2 (en) * | 1999-04-12 | 2003-10-16 | Chk Wireless Technologies Australia Pty Limited | Apparatus and method for electrical measurements on conductors |
CN112834812A (en) * | 2021-01-06 | 2021-05-25 | 南京能晶电子科技有限公司 | Hall current sensor chip with strong anti-interference capability |
Also Published As
Publication number | Publication date |
---|---|
ZA962127B (en) | 1997-11-06 |
EP0879419A1 (en) | 1998-11-25 |
DE69621047D1 (en) | 2002-06-06 |
AU702196B2 (en) | 1999-02-18 |
US6037763A (en) | 2000-03-14 |
IN187455B (en) | 2002-04-27 |
EP0879419B1 (en) | 2002-05-02 |
ATE217090T1 (en) | 2002-05-15 |
DE69621047T2 (en) | 2002-12-19 |
AU4888196A (en) | 1996-10-02 |
GB9505314D0 (en) | 1995-05-03 |
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