Hitachi Metals, Ltd.

Naoki Futakuchi

Katsuya Akimoto

Ken Okuyama

Jun Umetsu

Yujiro Tomita

Haruyasu Komano

Naofumi Chiwata

Yukio Ikeda

Kazuhisa Takahashi

Takahiro Futatsumori

Shinya Hayashi

Sachio Suzuki

Hisashi Tate

Masaki Noguchi

A current sensor includes a bus bar in which a current to be detected flows, a circuit board mounted with a magnetic detection element thereon to detect a strength of a magnetic field generated by a current flowing in the bus bar, and a housing including first and second housings provided in such a manner as to sandwich the bus bar and the circuit board therebetween in a plate thickness direction of the bus bar. The first and second housings include slide guide portions respectively which are relatively slidable in a sloping direction with respect to the plate thickness direction of the bus bar while abutting each other in the plate thickness direction of the bus bar.

Current sensor

A current detection method for a current detection device including magnetism detection elements that detect magnetic flux density and output a voltage signal corresponding to the magnetic flux density is provided. The method includes acquiring measured value data that is obtained as a result of providing magnetic flux density in a detectable range of the magnetism detection elements that indicates the relationship between the magnetic flux density and an output voltage signal from the current detection device. Next, computational processing is performed so as to fit the acquired measured value data to a formula that includes plural factors and indicates the output voltage of the magnetism detection elements, thereby calculating the plural factors, and correcting the output voltage signal from the magnetism detection elements in accordance with the calculated factors so as to be approximately linear with respect to the magnetic flux density. Finally, a corrected voltage signal obtained by the correction is outputted.

Current detection method, current detection device, signal correction method for current detection device, and signal correction device for current detection device

A current sensor includes three bus bars arranged in such a manner to be spaced and aligned in a width direction thereof. A first shield plate and a second shield plate, which are made of a magnetic material, are arranged in such a manner to sandwich the three bus bars therebetween together in a thickness direction perpendicular to the width direction. Three magnetic detection elements are arranged between the three bus bars respectively and the first shield plate to detect a magnetic field strength generated by currents flowing through the corresponding bus bars. A conductive plate is disposed between each of the magnetic detection elements and the first shield plate. The conductive plate is disposed in such a manner to sandwich the three bus bars together between the conductive plate and the second shield plate. The conductive plate is made of a nonmagnetic conductive material.

A current sensor includes first and second bus bars aligned and arranged in such a manner to be spaced from each other in a plate width direction, a third bus bar arranged in such a manner that a plate thickness direction thereof coincides with a plate thickness direction of the first and second bus bars and a length direction thereof is orthogonal to a length direction of the first and second bus bars, first and second magnetic detection elements arranged opposite the first and second bus bars respectively in the plate thickness direction, and a third magnetic detection element arranged opposite the third bus bar in the plate thickness direction. The first and second magnetic detection elements are gradient detection type magnetic detection elements and are arranged in such a manner that a detection axis direction thereof is perpendicular to the length direction of the first and second bus bars and is tilted with respect to the plate thickness direction of the first and second bus bars. The third magnetic detection element is arranged in such a manner that a detection axis direction thereof coincides with a plate width direction of the third bus bar.

A current sensor includes a bus bar through which a measured current is carried, a pair of shielding plates that include a magnetic material, and are arranged to sandwich the bus bar in a thickness direction of the bus bar, and a magnetic detection element that is arranged between the bus bar and one of the shielding plates, and detects an intensity of magnetic field caused by the current carried through the bus bar. The shielding plate has a length of not less than 20 mm in a length direction of the bus bar, and a width of not less than 24 mm and not more than 38 mm in a width direction orthogonal to the length direction.

A current sensor includes plural bus bars which are each formed rectangular in a cross section, a pair of shield plates that include a magnetic material and are arranged so as to collectively sandwich the plural bus bars therebetween, and plural magnetic detection elements that are each arranged between the bus bars and one of the shield plates. A distance d between a detection position of a magnetic field intensity at an arbitrary one of the magnetic detection elements and a center position in the width direction between one of the bus bars corresponding to the arbitrary magnetic detection element and an other of the bus bars adjacent thereto in the width direction satisfies the following expression: d/w+0.023(w/h)&#x2265;0.36 where a width of the shield plates is w and an interval along a height direction of the shield plates is h.

A current sensor includes two bus bars, each of which is formed in a plate shape, the two bus bars being aligned and arranged so as to be spaced apart from each other in a plate width direction thereof, and magnetic detection element arranged opposite the two bus bars, respectively, in a plate thickness direction of the bus bars to detect a magnetic field strength generated by a current flowing through the corresponding bus bars. The magnetic detection element are gradient detection type magnetic detection elements that output a difference between magnetic field strengths detected at two magnetic sensing positions, respectively, and are arranged in such a manner that a detection axis direction thereof is perpendicular to a length direction of the bus bars and is tilted with respect to the plate thickness direction.

An electric current detection device includes magnetism detector elements for detecting a strength of a magnetic field generated by an electric current flowing through an electric current path, a detection circuit for detecting a magnitude of an electric current flowing through the electric current path based on an output of the magnetism detector elements, and plural wires that are connected to the magnetism detector elements and extend in a direction away from the electric current path. The magnetism detector elements are arranged such that a direction of a magneto-sensitive axis thereof lies on a first plane parallel to a current-carrying direction of the electric current path and parallel to an extending direction of the plurality of wires. The plural wires are arranged on a same plane of a second plane orthogonal to the first plane.

Electric current detection device and electric current detection method

A current sensor includes a bus bar through which an electric current to be measured flows, a first magnetic sensing element including a first magneto-sensitive portion including a magneto-resistive element, and a second magnetic sensing element including a second magneto-sensitive portion including a magneto-resistive element. Strength of a magnetic field generated by the electric current sensed by the first magneto-sensitive portion is different from a strength of the magnetic field sensed by the second magneto-sensitive portion. A first bias magnetic field is applied to the first magneto-sensitive portion and a second bias magnetic field in a direction opposite to a direction of the first bias magnetic field is applied to the second magneto-sensitive portion.

A current detector includes a half-bridge configuration including first and second magnetic detection elements that are connected in series and disposed such that a magnetization direction of a magnetic pinned layer thereof is opposite to each other, and a bias magnetic field generating means for applying a bias magnetic field to the first and second magnetic detection elements. The bias magnetic field has a substantially same intensity and is formed in a direction substantially orthogonal to the magnetization direction and opposite to each other.

Current detector that prevents fluctuatons in detection sensitivity

A current detection device includes plural bus bars, plural magnetic detection elements that are arranged respectively corresponding to the bus bars, a magnetic shield arranged to surround parts of the bus bars and the magnetic detection elements, a correction factor calculation unit that, on the basis of voltages output from the magnetic detection elements when any two or more of the bus bars are supplied with inversely phased currents, calculates correction factors for correcting mutual interference between the magnetic detection elements, a recording medium that holds the correction factors calculated by the correction factor calculation unit, and a current calculation unit that, using the correction factors held in the recording medium, calculates the currents flowing through the bus bars on the basis of the voltages output from the magnetic detection elements.

Current detection device and correction factor calculation method

A current sensor includes, a bus bar through which a current flows, a magnetic detection element detecting a magnetic field intensity generated by the current, first and second shielding plates arranged so as to sandwich the bus bar between the first and second shielding plates, a first conductive plate made of a conductive nonmagnetic material, arranged between the bus bar and the first shielding plate, and a second conductive plate made of the conductive nonmagnetic material, arranged between the bus bar and the second shielding plate, wherein the magnetic detection element is arranged at a first conductive plate-side. A distance between the first conductive plate and the bus bar is longer than a distance between the second conductive plate and the bus bar. The first conductive plate includes a slit formed in the first conductive plate at an overlapping position, and the slit pierces the first conductive plate.

A current sensor includes a busbar carrying an electric current to be measured, a magnetic sensing element for detecting intensity of a magnetic field generated by the current flowing through the busbar, and a pair of shield plates that include magnetic materials and are arranged to sandwich the busbar in a thickness direction of the busbar. The shield plates include a conductive shield plate including a conductive magnetic material and a non-conductive shield plate including a non-conductive magnetic material. The conductive shield plate includes a slit penetrating therethrough. The magnetic sensing element is arranged at a position where the magnetic sensing element overlaps the slits in the thickness direction and does not overlap the conductive shield plate in the thickness direction.

A current sensor includes a busbar carrying an electric current to be measured, a magnetic sensing element for detecting intensity of a magnetic field generated by the current flowing through the busbar, and a pair of shield plates that include a magnetic material and are arranged to sandwich the busbar in a thickness direction of the busbar. The busbar includes a through-hole penetrating therethrough and current paths formed on both sides of the through-hole, the magnetic sensing element is arranged at a position overlapping the through-hole in the thickness direction of the busbar. The busbar is arranged in a space between the pair of shield plates such that the center in the thickness direction is located at a position offset from the center of the space in the thickness direction.

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 Ito Iflowing through each of the bus bars based on formula (1) below, Bto Bare a magnetic flux density and Ito Iare an electric current.

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Hitachinaka, Japan

Naoki Futakuchi