Patent ID: 7969140
Filing Date: 2011-06-28
Classification: G01R

Abstract:
1. Open-loop electrical current sensor for measuring a primary electrical current I p flowing in a primary conductor ( 1 ), including a magnetic circuit ( 3 ) comprising a generally annular shaped core ( 5 ) of soft magnetic material surrounding a central opening ( 7 ) configured to allow a primary conductor to extend therethrough and having an air-gap ( 6 ) formed between end faces ( 27 a , 27 b ) of said core, and a magnetic field sensor positioned in the air-gap, the magnetic field sensor comprising a magnetic field sensing cell ( 10 , 310 ) and a magnetic shield ( 9 , 109 , 209 , 409 ) made of a magnetic material comprising at least two parts ( 12 , 112 , 212 , 412 ) separated by an air-gap ( 20 ) and surrounding the magnetic field sensing cell positioned within a cavity ( 11 ) of the magnetic shield, the magnetic field sensing cell comprising a saturable soft magnetic core ( 17 , 317 ) surrounded by a coil ( 16 ) connected to a circuit for generating and processing the electrical signals of the magnetic field sensing cell in order to provide an output signal that is a function of the primary electrical current.