DC metering device and method
AssigneeABB Schweiz AG
InventorStefan Raaijmakers
Life of this patent
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Abstract
A DC metering device includes: two current transducers comprising hall sensors for measuring direct currents; two electrical switches; and a control device. Each one current transducer and one switch are connected in series by series connections. The series connections of the current transducers and switches are connected in parallel. The control device switches off in a repeating sequence alternately one of the switches and to continuously calculate a sum of continuously measured direct currents subtracted by measured zero offset currents of the two current transducers. The zero offset currents are measured when no current goes through the current transducers.
Claims19
A DC (direct current) metering device, comprising:
- two current transducers comprising hall sensors configured to measure direct currents;
- two electrical switches;
- and
- a control device,
- wherein each one current transducer and one switch are connected in series by series connections,
- wherein the series connections of the current transducers and switches are connected in parallel,
- wherein the control device is configured to switch off in a repeating sequence alternately one of the switches and to continuously calculate a sum of continuously measured direct currents subtracted by measured zero offset currents of the two current transducers, and
- wherein the zero offset currents are measured when no current goes through the current transducers.
A method for determining a direct current, comprising:
- providing two current transducers comprising hall sensors, the two current transducers being configured to measure direct currents and two electrical switches, each one current transducer and one switch being connected in series by series connection, the series connections of the current transducers and switches being connected in parallel;
- switching off in a repeating sequence alternately one of the switches;
- and
- continuously calculating a sum of continuously measured direct currents subtracted by the measured zero offset currents of the two current transducers, the zero offset currents being measured when no current goes through the current transducers.
Dependencies are inferred from the claim text.