Current sensing techniques. In an example, a current sensing method includes: generating a first magnetic field measurement; generating a second magnetic field measurement; generating a frequency estimate of a current; calculating a root-mean-square (RMS) value of an estimated amplitude of the current; and generating a temperature estimate of an integrated circuit (IC) configured to perform the method. The method also includes generating a first weighting factor and a second weighting factor based on the frequency estimate, the RMS value, and the temperature estimate, the first weighting factor to control amplification of the first magnetic field measurement and the second weighting factor to control amplification of the second magnetic field measurement.

A system includes a monitoring and/or protection system that includes an insulation derivation circuit. The insulation derivation circuit is configured to derive a first temperature compensation curve based on a first temperature and a first current, and the monitoring and/or protection system is configured to communicatively couple to a first current sensor configured to sense the first current traversing a first phase of a stator winding of a motor, a generator, or a combination thereof. The insulation derivation circuit is also configured to communicatively couple to a first temperature sensor configured to sense the first temperature of the stator when the stator is energized, and the temperature compensation curve is configured to map a temperature to a leakage dissipation factor.

An energy monitoring device includes a power supply circuit electrically coupled to a power source via a hot conductor and a load via a load conductor; a relay circuit including a relay and a relay driver circuit, where the relay includes a plurality of coils and the relay contact electrically coupled to the hot conductor and the load conductor; a sensing circuit including a hot voltage sensor and a load voltage sensor; and a controller electrically coupled to the power supply circuit, the relay driver circuit, and the sensing circuit, and structured to receive a hot voltage from the hot voltage sensor and a load voltage from the load voltage sensor, and determine a load current based at least in part on a relay contact resistance of the relay contact and a delta between the hot voltage and the load voltage.

An energy monitoring device includes a power supply circuit electrically coupled to a power source via a hot conductor and a load via a load conductor; a relay circuit including a relay and a relay driver circuit, where the relay includes a plurality of coils and the relay contact electrically coupled to the hot conductor and the load conductor; a sensing circuit including a hot voltage sensor and a load voltage sensor; and a controller electrically coupled to the power supply circuit, the relay driver circuit, and the sensing circuit, and structured to receive a hot voltage from the hot voltage sensor and a load voltage from the load voltage sensor, and determine a load current based at least in part on a relay contact resistance of the relay contact and a delta between the hot voltage and the load voltage.

The invention relates to a device (200) for measuring a current through a choke (130) of a voltage converter (100) comprising an integrator circuit (140), an amplifier circuit and an NTC resistor (160). The amplifier circuit comprises an inverting and a non-inverting amplifier input connection (152, 154) and an amplifier output connection (156). The non-inverting amplifier input connection (154) is supplied with an amplifier input signal according to an integrator output signal. A voltage signal characterising the current through the choke (130) is applied at the amplifier output connection (156) of the amplifier circuit. The NTC resistor (160) is arranged in the feedback path of the amplifier circuit between the inverting amplifier input connection (152) and the amplifier output connection (156).

The invention relates to a device (200) for measuring a current through a choke (130) of a voltage converter (100) comprising an integrator circuit (140), an amplifier circuit and an NTC resistor (160). The amplifier circuit comprises an inverting and a non-inverting amplifier input connection (152, 154) and an amplifier output connection (156). The non-inverting amplifier input connection (154) is supplied with an amplifier input signal according to an integrator output signal. A voltage signal characterising the current through the choke (130) is applied at the amplifier output connection (156) of the amplifier circuit. The NTC resistor (160) is arranged in the feedback path of the amplifier circuit between the inverting amplifier input connection (152) and the amplifier output connection (156).

A current sensing system includes a pre-calibrated busbar, a voltage sensor, a temperature sensor and a controller. The pre-calibrated busbar has a known resistance, a known variation in resistance with respect to temperature and known dimensions. The voltage sensor detects a difference in voltage between a first location and a second location on the pre-calibrated busbar. The temperature sensor detects an ambient temperature of the pre-calibrated busbar. The controller determines a resistance of the busbar between the first location and the second location based on the known resistance, known variation in resistance, known dimensions and the ambient temperature. The controller additionally determines a current flowing through the pre-calibrated busbar based on the difference in voltage and the determined resistance. The current sensing system has numerous applications including using the determined current to control an operating condition of a solid state circuit breaker or a solid state power controller.

A current sensing system includes a pre-calibrated busbar, a voltage sensor, a temperature sensor and a controller. The pre-calibrated busbar has a known resistance, a known variation in resistance with respect to temperature and known dimensions. The voltage sensor detects a difference in voltage between a first location and a second location on the pre-calibrated busbar. The temperature sensor detects an ambient temperature of the pre-calibrated busbar. The controller determines a resistance of the busbar between the first location and the second location based on the known resistance, known variation in resistance, known dimensions and the ambient temperature. The controller additionally determines a current flowing through the pre-calibrated busbar based on the difference in voltage and the determined resistance. The current sensing system has numerous applications including using the determined current to control an operating condition of a solid state circuit breaker or a solid state power controller.

A reference load includes a parallel connection of a resistor load having a resistor and a transistor load having a plurality of transistors, wherein a temperature coefficient of the resistor load is positive, and a temperature coefficient of the transistor load is negative.

Sensor part for installation in medium-voltage cable compartments, which sensor part comprises a voltage divider based on the capacitive divider principle, which voltage divider comprises: —a first capacitor, comprising an elongate primary conductor wrapped in a dielectric material and an elongate conducting shield arranged around the dielectric material, which first capacitor has a first capacitance rating; —a second capacitor, having a second capacitance rating, which second capacitor further comprises a first lead conductively connected with the conducting shield of the first capacitor and a second lead conductively connected to a common reference, such as earth; —a voltage output line, conductively connected with the conducting shield of the first capacitor; wherein the second capacitance rating is larger than the first capacitance rating, so that when during use the primary conductor is conductively connected with a live circuit carrying an alternating current, a measurement of a voltage between the common reference and the voltage output line can be taken as a ratio of the voltage between the live circuit and the common reference.