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EP-4575520-B1 - CURRENT TRANSDUCER WITH SHUNT

EP4575520B1EP 4575520 B1EP4575520 B1EP 4575520B1EP-4575520-B1

Inventors

  • TROMBERT, Stéphan

Dates

Publication Date
20260506
Application Date
20231222

Claims (14)

  1. A shunt current transducer (1) comprising a primary conductor (2) including a busbar portion with a substantially rectangular cross section, and a measurement processing unit (3) mounted against and connected to the primary conductor, the measurement processing unit (3) comprising a circuit board (7) and a signal processing circuit (8) on the circuit board, the primary conductor comprising a plurality of shunt sections (4) connected in series, including at least a first shunt section (4a) and a second shunt section (4b), each shunt section bounded by a terminal set (5) arranged at each end of the respective shunt section, said terminal sets comprising terminals formed on the circuit board (7), the signal processing circuit (8) comprising a first measurement channel (9) connected to the first shunt section (4a), and a second measurement channel (10) connected to the second shunt section (4b), characterized in that the first and second shunt sections are directly adjacent each other and comprise a terminal set that forms the interface between the adjacent first and second shunt sections.
  2. The shunt current transducer according to claim 1 wherein the first measurement channel (9) comprises a first integrated circuit chip (11a) connected to the terminal sets at ends of the first shunt section (4a), and a second integrated circuit chip (11b) connected to the terminal sets at ends of the second shunt section (4b).
  3. The shunt current transducer according to any preceding claim wherein the signal processing circuit is configured to cross check measurement values between the first measurement channel and the second measurement channel.
  4. The shunt current transducer according to any preceding claim wherein the material of the first shunt section is different from the material of the second shunt section.
  5. The shunt current transducer according to any preceding claim wherein the material of the first shunt section (4a) comprises or consists of a Cu-Ni-Mn alloy, preferably Manganin.
  6. The shunt current transducer according to any preceding claim wherein the material of the second shunt section (4b) is the main material forming the primary conductor.
  7. The shunt current transducer according to the preceding claim wherein the main material forming the primary conductor comprises an alloy with copper of more than 90%, or comprises a copper aluminium alloy.
  8. The shunt current transducer according to any preceding claim wherein at least one of the terminal sets comprises a plurality of terminals greater than five distributed across the width of the associated shunt section substantially in a line.
  9. The shunt current transducer according to the preceding claim wherein the plurality of terminals of a terminal set are spaced part evenly from each other.
  10. The shunt current transducer according to either of the two directly preceding claims wherein all of the terminal sets comprise a plurality of connection terminals greater than five distributed across the width of the respective shunt sections, orthogonal to the direction of flow of the primary current through the shunt sections.
  11. The shunt current transducer according to any of the three directly preceding claims wherein each shunt terminal is connected to a resistance, said resistances being connected in parallel to an input of the respective measurement channel.
  12. The shunt current transducer according to any preceding claim wherein the shunt terminals comprise conductive pads formed on the circuit board soldered to the primary conductor.
  13. The shunt current transducer according to any preceding claim wherein the primary conductor comprises transducer terminals (6) configured for a mechanical connection to corresponding terminals of an external primary conductor.
  14. The shunt current transducer according to any preceding claim wherein primary conductor comprises a third shunt section (4c) connected in series to the first and second shunt sections (4a, 4b), optionally wherein the third shunt section has the same material as the second shunt section, and a different material from the first shunt section which is arranged between the second and third shunt sections.

Description

The present invention relates to a current transducer based on a shunt resistor. One of the known shunt transducer configurations, in particular for high current applications, comprises a bus bar, typically in the form of a rectangular profiled bar configured to be clamped or otherwise connected to a primary conductor carrying the current to be measured. The bus bar typically has a section of a shunt material such as Manganin - a copper, manganese, nickel alloy - integrally formed and connected to the copper bus bar on either end, whereby the resistance across the shunt material section is measured. The shunt material Manganin is used because of it's low temperature coefficient of resistance value and it's long term stability. Thus, there is a higher measurement accuracy over a large range of temperatures compared to copper or other metals and alloys. It is known to position one or two contacts on the copper sections of the bus bar bordering the shunt section, to pick up the voltage across the shunt section and determine the current flowing through the shunt section. Depending on the frequency and amplitude of the electrical current, the one or two terminals on each border of the shunt section may not allow to optimally measure the primary current to be measured in a precise manner. In many applications, for instance in the automotive field, it is important for safety and reliability reasons to have a redundant measurement signal, which generally requires a second current transducer. This however increases costs and takes space, and may also affect reliability due to the increased number of components. In view of the foregoing, it is an object of this invention to provide a shunt current transducer that is safe and reliable, yet economical. It is advantageous to provide a shunt current transducer that is precise over a large range of operating conditions. It is advantageous to provide a shunt current transducer that is compact. It is advantageous, for certain applications, to provide a shunt current transducer that is adapted for the measurement of high currents and has the form of a bus bar that may be coupled to standard circuits provided with bus bar terminal connections. Various current transducers comprising a shunt resistor or resistive measurement conductor section are described in US2017/089955, DE102019218308, EP3851859, DE 102021210139, WO2021/014872, DE112019004609, EP2981833, and DE102020111634B3. Objects of this invention have been achieved by providing a system according to claim 1. Dependent claims set forth various advantageous features of embodiments of the invention. Disclosed herein is a shunt current transducer comprising a primary conductor including a busbar portion with a substantially rectangular cross section, and a measurement processing unit mounted against and connected to the primary conductor, the measurement processing unit comprising a circuit board and a signal processing circuit on the circuit board. The primary conductor comprises a plurality of shunt sections connected in series, including at least a first shunt section and a second shunt section, each shunt section bounded by a terminal set arranged at each end of the respective shunt section, said terminal sets comprising terminals formed on the circuit board, the signal processing circuit comprising a first measurement channel connected to the first shunt section and a second measurement channel connected to the second shunt section. The first and second shunt sections are directly adjacent each other and comprise a terminal set that forms the interface between the adjacent first and second shunt sections. In an embodiment, the first measurement channel comprises a first integrated circuit chip connected to the terminal sets at ends of the first shunt section, and a second integrated circuit chip connected to the terminal sets at ends of the second shunt section. In an embodiment, the signal processing circuit is configured to cross check measurement values between the first measurement channel and the second measurement channel. In an embodiment, the material of the first shunt section is different from the material of the second shunt section. In an embodiment, the material of the first shunt section comprises or consists of a Cu-Ni-Mn alloy, preferably Manganin. In an embodiment, the material of the second shunt section (4b) is the main material forming the primary conductor. In an embodiment, the main material forming the primary conductor comprises an alloy with copper of more than 90%, or comprises a copper aluminium alloy. In an embodiment, at least one of the terminal sets comprises a plurality of terminals greater than five distributed across the width of the associated shunt section substantially in a line. In an embodiment, the plurality of terminals of a terminal set are spaced part evenly from each other. In an embodiment, all of the terminal sets comprise a plurality of connection terminals greater than f