Hioki E.e. Corporation

Kenta Ikeda

Koki Nakazawa

Kimihiko Yamagishi

Yuki Karasawa

Yutaka Ashida

Takafumi Maruyama

A current sensor includes an excitation detection winding configured such that an excitation signal for exciting a second magnetic core is input, the excitation detection winding detects magnetic flux flowing through the second magnetic core and outputs a detection signal indicating a measurement-target current. The current sensor includes an auxiliary winding that detects the magnetic flux and outputs an auxiliary signal indicating the measurement-target current. The current sensor includes a feedback winding wound around first and second magnetic cores, the feedback winding being configured such that a signal generated from the detection signal is input, and the feedback winding being wound to cancel out magnetic flux of the first and second magnetic cores. The current sensor includes a circuit to output an output signal indicating a level of the measurement-target current by modifying a signal output from the feedback winding based on a correction signal generated from the auxiliary signal.

Current sensor

A current sensor for detecting a magnitude of a current flowing through a measuring object has a magnetic core having a first magnetic core and a second magnetic core that is arranged magnetically in parallel to the first magnetic core, wherein the first magnetic core has a magnetic permeability that is higher than that of the second magnetic core in a first frequency band, and the first magnetic core has a magnetic permeability that is lower than that of the second magnetic core in a second frequency band, the second frequency band being higher than the first frequency band, and the current sensor detects the magnitude of the current in a frequency band that is constituted by combining the first frequency band and the second frequency band.

A current detector includes: a current sensor that is constructed using a Rogowski coil, detects a current flowing in a measured object, and outputs a detection signal corresponding to a current value of the current; a transfer line that is constructed of a distributed constant line and transfers the detection signal; an impedance converting circuit that is provided between the current sensor and the transfer line and has an input impedance equal or substantially equal to a characteristic impedance of the current sensor; an integrator circuit that integrates the detection signal inputted via the transfer line and outputs an output signal indicating a current value of the current; and a resistance circuit that has a resistance value that is equal or substantially equal to a characteristic impedance of the transfer line and is connected in series between the transfer line and the integrator circuit.

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Nagano, Japan

Kenta Ikeda