A measuring shunt includes a resistance element and a magnetic core. The resistance element includes two main contacts and a middle section extending between the main contacts for conducting an electrical current between the two main contacts through the middle section. The magnetic core extends in an annular manner around the middle section of the resistance element.

A measuring arrangement for redundantly determining a quantitative value of a current flow includes a first and second current-measuring modules connected in parallel, where the first current-measuring module includes a first analogue input and a first current measurement resistor and a voltage-measuring unit to determine the value of current flowing into the analogue input and through the first current measurement resistor, the second current measuring module includes a second analogue input and a second current measurement resistor and a voltage-measuring unit to determine the value of current flowing into the second analogue input and through the second current measurement resistor, and includes a control unit that detects a gradual change in voltages determined by the voltage-measuring units, and when gradual changes in the voltages that are counter to each other occur, a current-measuring module is excluded from the determination of the quantitative value of the current flow.

Systems, methods, and an apparatus for current monitoring are disclosed. A current monitor comprises a high-voltage side configured to obtain a signal indicative of current through a conductor and apply different levels of gain to different frequency bands of the signal to produce an adjusted signal. A low-voltage side of the current monitor is electrically isolated from the high-voltage side and is configured to split the adjusted signal to produce a plurality of output signals that are each indicative of a level of current at one of the different frequency bands. An isolation amplifier is configured to communicate the adjusted signal from the high-voltage side to the low-voltage side while electrically isolating the high-voltage side from the low-voltage side.

A system current sensor module can accurately sense or measure system current flowing through a sense current resistor by shunting current through a gain-setting resistor and using an amplifier to measure a resulting voltage, with an output transistor controlled by the amplifier controlling current through the gain setting resistor in a manner that tends to keep the amplifier inputs at the same voltage. The resistors can be thermally coupled to maintain similar temperatures when a system current is flowing. The thermal coupling can include conducting heat from a first resistor layer carrying the current sense resistor to a thermal cage layer located beyond a second resistor layer carrying the gain-setting resistor. This preserves accuracy, including during aging.

A shunt resistor module which is coupled to a printed circuit board to be used for current measurement, includes: a resistor portion configured to have predetermined resistance; at least two terminal portions configured to extend from opposite ends of the resistor portion; lead pins fixed to first sides of the terminal portions to protrude to be electrically connected to the printed circuit board; and an exterior member formed to at least partially cover first surfaces of the terminal portions and to have pin holes opened to expose the lead pins and screw holes formed to be screwed to the printed circuit board.

A three-phase load is powered by a PWM (e.g., SVPWM) driven DC-AC inverter having a single shunt-topology. A shunt voltage and a branch voltage of the inverter (across a transistor to be calibrated) are measured during a second period of each SVPWM sector, and the drain-to-source resistance of the calibrated transistor is calculated. During the fourth period of each SVPWM sector, the branch voltage is measured again, and another branch voltage across another transistor is measured. Using the drain-to-source resistance of the calibrated transistor and the voltage across the calibrated transistor measured during the fourth period, the phase current through the calibrated transistor is calculated. Using the other branch voltage measured during the fourth period and the drain-to-source resistance of its corresponding transistor (known from a prior SVPWM sector), the phase current through that transistor is calculated. From the two calculated phase currents, the other phase current can be calculated.

A current sensing circuit is provided for measuring a current in an electrical line connecting an electrical supply to a load. The current sensing circuit includes a magnetic circuit having: a magnetic core, a reference winding wound around the magnetic core, and a conductor passing through center of the magnetic core. The conductor is being connected to the electrical line. The current sensing circuit further includes a detection circuit connected to the reference winding of the magnetic circuit. The detection circuit is configured to detect a change in condition of the magnetic core and generate a detection signal in response to determination of the change. Furthermore, the current sensing circuit includes a controller coupled to the detection circuit for receiving the detection signal. The controller measures the current in the electrical line in response to the detection signal from the detection circuit.

According to some embodiments, a device includes: a magnetic field current sensor magnetically coupled to a conductor and configured to generate a magnetic field signal having a magnitude responsive to a current flowing through the conductor; a shunt interface having first and second input terminals electrically coupled to ends of a shunt disposed along the conductor, the shunt interface configured to generate a shunt signal having a magnitude responsive to the current flowing through the conductor; and a diagnostic circuit configured to receive the magnetic field signal and the shunt signal and to generate a fault signal based on a comparison between the magnitude of the magnetic field signal and the magnitude of the shunt signal.

A current detection circuit includes: a detection resistor provided between an output of a driver circuit and a load; a power supply circuit configured to operate between a first power supply and a virtual ground potential, and generate a second power supply having a predetermined voltage difference from the virtual ground potential; and a signal processing circuit configured to operate between the second power supply and the virtual ground potential, and generate a detection signal corresponding to a voltage generated at the detection resistor. A virtual ground line for supplying the virtual ground potential is connected between the output of the driver circuit and the detection resistor.

Disclosed herein are devices (100), systems, and methods for testing a circuit (114). A circuit test device (100) includes a housing (102) and a circuit (104) disposed in the housing (102). The circuit (104) includes an electromagnetic field (EMF) sensor (106) and a signal detector (110) coupled to the EMF sensor (106). The circuit test device (100) includes an interface (112) connected to the circuit (104) and extending through the housing (102). The interface (112) is adapted for coupling the circuit (104) to a circuit under test (CUT) (114). The EMF sensor (106) is configured to generate a signal in the presence of a time varying flow of current from the CUT (114) in the circuit (104). The EMF sensor (106) is configured to provide the signal to the signal detector (110).