Arrangement for measuring electrical power
First Claim
1. An arrangement for measuring electrical power comprising:
- an electrical conductor traversed by an electrical current i,a Hall element,a voltage-to-current converter for transforming an electrical voltage uN into a proportional supply current iN for said Hall element, said Hall element being adapted to produce an intelligence containing output signal uH that is proportional to the product (±
i·
uN) of the current i and the voltage uN,a ferromagnetic core that has at least one air gap and is excited by the current i, said Hall element being arranged in said air gap,a voltage-to-frequency converter for transforming the Hall element output voltage ±
uH into a proportional pulse frequency, said voltage-to-frequency converter having an integrator including a capacitor and at least two signal sources, andswitching means for periodically switching an intelligence containing signal component proportional to said signal ±
uH and for switching said signal sources to compensate an offset voltage.
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Accused Products
Abstract
The present invention is an arrangement for measuring electrical power. The arrangement comprises a conductor traversed by an electrical current i and a voltage-to-current converter for transforming an electrical voltage uN into a proportional supply current iN for a Hall element. The Hall element is adapted to produce an intelligence containing output signal ±uH proportional to the product (±i.uN) of the current i and the voltage ±uN. The Hall element is arranged in an air-gap of a ferromagnetic core that is excited by the current i. A voltage-to-frequency converter transforms the Hall element output voltage ±uH into a proportional output frequency. The voltage-to-frequency converter includes a capacitor for integration purposes and at least two signal sources. The power measuring device also includes a switch for periodically switching a signal proportional to the signal ±uH and for switching said signal sources to compensate for an offset voltage. Use of the arrangement permits an improvement in the ratio of the intelligence containing signal to an interference signal, which interference signal includes for example an offset voltage.
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Citations
42 Claims
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1. An arrangement for measuring electrical power comprising:
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an electrical conductor traversed by an electrical current i, a Hall element, a voltage-to-current converter for transforming an electrical voltage uN into a proportional supply current iN for said Hall element, said Hall element being adapted to produce an intelligence containing output signal uH that is proportional to the product (±
i·
uN) of the current i and the voltage uN,a ferromagnetic core that has at least one air gap and is excited by the current i, said Hall element being arranged in said air gap, a voltage-to-frequency converter for transforming the Hall element output voltage ±
uH into a proportional pulse frequency, said voltage-to-frequency converter having an integrator including a capacitor and at least two signal sources, andswitching means for periodically switching an intelligence containing signal component proportional to said signal ±
uH and for switching said signal sources to compensate an offset voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
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Specification