505results about "Measurement using dc-ac conversion" patented technology

A current sensor is described that uses a plurality of magnetic field sensors positioned around a current carrying conductor. The sensor can be hinged to allow clamping to a conductor. The current sensor provides high measurement accuracy for both DC and AC currents, and is substantially immune to the effects of temperature, conductor position, nearby current carrying conductors and aging.

An integrated sensor includes a magnetoresistance element electrically coupled to a device disposed on or integrated in a silicon substrate. A conductor is provided proximate to the magnetoresistance element. The integrated sensor can be used to provide various devices, such as a current sensor, a magnetic field sensor, or an isolator. Further, the integrated sensor can be used in an open loop configuration or in a closed loop configuration in which an additional conductor is provided. The magntoresistance element may be formed over the silicon substrate or on a separate, non-silicon substrate. Also described is an integrated sensor comprising a substrate, a magnetic field transducer disposed over a surface of the substrate, and a conductor disposed over the surface of the substrate proximate to the magnetic field transducer. The magnetic field transducer can be a Hall effect transducer or a magnetoresistance element.

A current sensor assembly includes a sensor coil, an electrostatic shield coil, a core, a housing, and a magnetic shield. The sensing coil, electrostatic shield coil, core, housing, and magnetic shield can be of toroidal symmetry and arranged coaxially about a pair of primary current conductors. The conductors can be either asymmetric or symmetric with respect to the geometric center of the remaining sensor assembly. The core and a secondary winding make up a current sensor. The core is cylindrically shaped and fabricated of non-magnetic material. The secondary winding is wound over the cylindrical core to form a toroidally shaped winding. When assembled into the current sensor assembly, the core and windings are disposed around two single turn primary windings through which AC currents to be measured flow. Alternatively, the conductor can be flat and the sensor can be a solid state sensor that includes an electrostatic shield. The conductor can have a magnetic flux concentrator positioned about the conductor in the same region where the sensor is located.

The present invention provides a current measuring apparatus having an improved structure to inhibit the possible adverse effect of a current in a different phase and the possible generation of an induced electromotive force caused by a measurement target current, enabling the measurement target current to be accurately detected even with the small size of the apparatus. The current measuring apparatus includes a printed circuit board 1 having Hall elements 2a, 2b and a signal processing integrated circuit 3 mounted thereon, the Hall elements 2a, 2b sensing a magnetic field generated by a current flowing through a current measurement target bus bar 4a, the signal processing integrated circuit 3 processing sensing outputs from the Hall elements 2a, 2b to calculate a value for the current flowing through the bus bar 4a. Magnetic sensing surfaces of the Hall elements 2a, 2b are arranged substantially perpendicularly to the direction of the magnetic field generated by the current flowing through the bus bar 4a. Further, the printed circuit board 1 is fixed to the bus bar 4a so that a circuit board surface of the printed circuit board 1 having a wire electrically connecting the Hall elements 2a, 2b to the signal processing integrated circuit 3 is positioned substantially parallel to the direction of the magnetic field.

The present invention provides a current sensor of smaller and simpler configuration, capable of measuring a current to be detected with high precision and stability. A current sensor has a V-shaped conductor line and a pair of magnetoresistive elements disposed along with the conductor line so that a resistance value of one of the magnetoresistive elements changes in a direction opposite to that of resistance-value-change of the other magnetoresistive element according to current magnetic fields produced by a current to be detected flowing through the conductor line.

A high-precision Rogowski current transformer, the Rogowski coil is realized in a single printed circuit board while maintaining both the outside field rejection of a traditional Rogowski coil, and the increased output voltage similar to the multiple printed circuit board Rogowski coil arrangements.

The present invention relates to an apparatus capable of diagnosing the aging state of a power conversion system at ordinary times and its diagnosing method to ensure the reliability of a power conversion system. The apparatus includes a current sensing means for detecting the output current of a inverter switching module or an electrolytic capacitor, and measurement and diagnosis means for extracting elements related to the aging status of the power conversion system by receiving the output current waveform of the inverter switching module and magnitude of each harmonic or an impedance voltage signal of the electrolytic capacitor. Furthermore, it is preferable that the apparatus further includes a measurement current generation means for generating measurement current to be supplied to the electrolytic capacitor. By analyzing an average value or the magnitude of harmonics by FFT analysis of the output current waveform of the inverter switching module and measuring an ESR value or a loss angle tan δ of a DC bus of the power conversion system, the present invention is able to monitor and diagnose the abnormal state attributable to the aging or degradation of the power conversion system in advance.

A current detector having a linear conductor 111, 112, a linear to-be measured conductor 10 disposed substantially in parallel to the conductor 111, 112 and through which a to-be measured current flows. A Hall element 20 disposed in the vicinity of the to-be measured conductor 10 such that a magnetic flux generated by the to-be measured current flowing through the to-be measured conductor 10 enter into a magnetic-force sensing face 21 substantially perpendicularly. A substrate 30 for supporting the conductor and the to-be measured conductor 10 such that the magnetic flux generated by a current flowing through the conductor becomes substantially parallel to the magnetic-force sensing face +21 in the magnetic-force sensing face 21 of the Hall element 20.

A magnetic field measuring device useful for measuring a magnetic field associated with an electric current, including a bus section connectable into the path of the electric current, a first magnetoresistive (MR) bridge oriented to be sensitive to the magnetic field of a current in the bus section, a second MR bridge oriented to be substantially insensitive to the magnetic field of a current in the bus section, a biasing coil configured and positioned to apply a magnetic field to the first and second MR bridges, whereby the sensitivity of the first MR bridge can be controlled; and a signal processing device responsive to a voltage output of the second MR bridge to control the current through the biasing coil. The device exhibits good rejection of stray magnetic and electric fields, is convenient to use, and can be fabricated in a single chip, with or without associated signal processing and conditioning circuitry, using conventional IC processing techniques.

A time varying current sensor is constructed using surface coils uniformly spaced around a central cavity adapted to receive the conductor through which the current to be measured flows. Accurate and uniform coil geometry is achieved using printed circuit board technology, thereby eliminating the high cost of precision toroidal coil winding. An optional hinge in the housing can allow the sensor to be easily installed on existing conductors without the need to disconnect and reconnect.

A current sensor includes first to fourth magneto-resistive elements each having a resistance value; and a compensation current line applying a compensation magnetic field to the magneto-resistive elements. A bridge circuit is formed by the magneto-resistive elements. Resistance values of the first and third magneto-resistive elements change together in one increasing/decreasing direction. Resistance values of the second and fourth magneto-resistive elements change together in the other increasing/decreasing direction. The compensation current is generated by a potential difference between the first and second junctions in response to application of voltage between the third and fourth junctions. The compensation current line includes first to fourth line portions. Each line portion extends in the same direction as the extending direction of the magneto-resistive elements, overlaps the corresponding magneto-resistive elements, and. The current-to-be-detected is detected based on the compensation current.

A clamp-on current and voltage module for an electrical power monitoring system that monitors characteristics of power distributed through one or more power conductors includes a current transformer having a core divided into at least two parts so that the core can be installed around a power conductor without cutting the conductor. The transformer produces a current signal corresponding to current passing through the power conductor. A pair of clamping elements fit on opposite sides of the conductor, for gripping the conductor. The transformer core parts and the clamping elements have engaging surfaces that prevent relative movement between the CT enclosure and the power conductor in a direction transverse to the axis of the power conductor. A voltage sensor makes electrical contact with the power conductor and produces a voltage signal corresponding to the voltage on the power conductor.

The present invention is directed to system and method for current sensing. A current sensor system includes a conductor configured to receive current flow therethrough and generate magnetic flux thereabout. The current sensor system also includes an anti-differential current sensor configured to monitor magnetic flux about the conductor and a flux concentrator configured to concentrate magnetic flux induced by current flow through the conductor.

A method and a current sensor for measuring a current in a conductor. The sensor comprises a non-magnetic, flexible core member having a first end and a second end. A locking head having a channel therethrough is coupled to the first end of the core member. A first sensor conductor winding layer is mounted on the core member. Wherein the second end releasably engages the locking thread in the channel and adjustably configures the core member to surround the conductor as the second end is moved through the channel. In another embodiment the current sensor includes a locking tang within the channel and a plurality of sought tooth members on a portion of the core member and configured to selectively engage the locking tang as the second end of the core member is moved through the channel.

A flexible current and voltage sensor provides ease of installation of a current sensor, and optionally a voltage sensor in application such as AC branch circuit wire measurements, which may require installation in dense wiring conditions and/or in live panels where insulating gloves must be worn. The sensor includes at least one flexible ferromagnetic strip that is affixed to a current sensing device at a first end. The second end is secured to the other side of the current sensing device or to another flexible ferromagnetic strip extending from the other side of the current sensing device to form a loop providing a closed pathway for magnetic flux. A voltage sensor may be provided by metal foil affixed to the inside of the flexible ferromagnetic strip. A clamp body, which can be a spring loaded handle operated clamp or a locking fastener, can secure the ferromagnetic strip around the wire.

An electronic circuit for sensing a current includes a circuit board having first and second major opposing surfaces and a current conductor for carrying the current. The current conductor includes a circuit trace disposed upon the circuit board. The electronic circuit also includes an integrated circuit disposed upon and electrically coupled to the circuit board at a position so as to straddle the current conductor.