Auto-zeroing current sensing element
First Claim
1. A current sensor for generating a signal representative of alternating current in a current-carrying conductor, said current sensor comprising:
- a magnetic core having first and second ends with a gap therebetween and shaped to form a conductor opening, said current-carrying conductor extending through said conductor opening; and
a current sensing element including a biasing coil for carrying a bias alternating current, said sensing element being positioned relative to said gap between said first and second ends of said magnetic core so that said sensing element moves when exposed to alternating magnetic fields of the current-carrying conductor and the biasing coil.
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Accused Products
Abstract
A current sensor for sensing alternating current in a current-carrying conductor includes a substantially C-shaped magnetic core having first and second ends with a gap therebetween. A current sensing element, which includes a microresonant element, is positioned proximate the gap between the first and second ends of the magnetic core such that the element oscillates when exposed to an alternating magnetic field. A biasing coil is attached to the micro-resonant element for carrying a bias current. The micro-resonant element resonates, or vibrates, at a standard oscillating frequency when no current is present in the biasing coil, and resonates at a modified oscillating frequency when current is present in both the biasing coil and the current-carrying conductor. The magnitude of current in the current-carrying conductor is determined as a multiple of the product of a ratio of the standard oscillating frequency and the modified oscillating frequency, and the bias current.
49 Citations
18 Claims
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1. A current sensor for generating a signal representative of alternating current in a current-carrying conductor, said current sensor comprising:
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a magnetic core having first and second ends with a gap therebetween and shaped to form a conductor opening, said current-carrying conductor extending through said conductor opening; and a current sensing element including a biasing coil for carrying a bias alternating current, said sensing element being positioned relative to said gap between said first and second ends of said magnetic core so that said sensing element moves when exposed to alternating magnetic fields of the current-carrying conductor and the biasing coil. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for measuring current in a current-carrying conductor using a current sensor including a magnetic core having first and second ends with a gap therebetween and shaped to form a conductor opening, said current-carrying conductor extending through said conductor opening, a current sensing element, and a bias alternating current source, the current sensing element including a biasing coil affixed thereto, the current sensing element being positioned proximate the gap so that the current sensing element moves in response to a magnetic field produced by the biasing coil, the biasing coil being electrically coupled to the bias alternating current source, said method comprising the steps of:
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determining current sensing element displacement in the presence of current in the biasing coil; and determining current magnitude in the current-carrying conductor from the determined current sensing element displacement. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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Specification