Electric current sensor

摘要

An electric current sensor includes a plurality of bus bars arranged in parallel, a plurality of magnetic detection elements that are adapted to detect a strength of a magnetic field generated by an electric current flowing through the bus bars and to output a voltage according to the strength of the magnetic field detected, and an arithmetic operation part to arithmetically operate an electric current flowing through the bus bars based on the voltage output from the plurality of magnetic detection elements. The arithmetic operation part includes a magnetic flux density arithmetic operation part to arithmetically operate a magnetic flux density based on the voltage, and an electric current arithmetic operation part to arithmetically operate an electric current I 1 to I m flowing through each of the bus bars based on formula (1) below, ( B 1 = a 11 ‹ I 1 + a 12 ‹ I 2 + ‹¯ + a 1 �¢ n ‹ I n B 2 = a 21 ‹ I 1 + a 22 ‹ I 2 + ‹¯ + a 2 �¢ n ‹ I n B 3 = a 31 ‹ I 1 + a 32 ‹ I 2 + ‹¯ + a 3 �¢ n ‹ I n ‹ ‹ ‹ ‹ ‹ ‹ B m = a m �¢ 1 ‹ I 1 + a m �¢ 2 ‹ I 2 + ‹¯ + a mn ‹ I n
where a 11 to a mn are coefficients,
B 1 to B m are a magnetic flux density and I 1 to I m are an electric current.