Systems and methods are disclosed for determining an input voltage level of an input voltage received by a connection cable. A monitoring component may determine whether the input voltage level matches one of a plurality of voltage levels. The connection cable may include an indicator component that may indicate which of the plurality of voltage levels matches the input voltage level.

A nested ammeter for measuring the electrical current flowing through a device under test (DUT) can include an input configured to receive an input signal having a frequency within a frequency band and representing the electrical current flowing through the DUT. The nested ammeter can also include an output configured to generate an output voltage representing the electrical current flowing through the DUT. An active shunt can be used as the resistive feedback of the ammeter. A nested active shunt can be used as the resistive feedback element of the active shunt.

In circuitry for measuring a voltage at a node, a capacitive divider is coupled to the node, wherein the capacitive divider provides a first output. A resistive divider is coupled to the node, wherein the resistive divider provides a second output.

A condition monitoring device for a wind turbine power generating apparatus provided with an auxiliary motor power supply system including a power-supply-side line connected to a power supply and a plurality of auxiliary-motor-side lines diverging from the power-supply-side line and connected to a plurality of auxiliary motors, respectively, comprises: a current measurement device for measuring a current flowing through the power-supply-side line; and a control device for controlling the plurality of auxiliary motors. The control device is configured to, when a generator of the wind turbine power generating apparatus is in a standby state where power generation is stopped at a low wind speed, execute a single sequential operation mode in which each of the plurality of auxiliary motors is singly and sequentially operated. The current measurement device is configured to measure a current flowing through the power-supply-side line during execution of the single sequential operation mode by the control device.

A condition monitoring device for a wind turbine power generating apparatus provided with an auxiliary motor power supply system including a power-supply-side line connected to a power supply and a plurality of auxiliary-motor-side lines diverging from the power-supply-side line and connected to a plurality of auxiliary motors, respectively, comprises: a current measurement device for measuring a current flowing through the power-supply-side line; and a control device for controlling the plurality of auxiliary motors. The control device is configured to, when a generator of the wind turbine power generating apparatus is in a standby state where power generation is stopped at a low wind speed, execute a single sequential operation mode in which each of the plurality of auxiliary motors is singly and sequentially operated. The current measurement device is configured to measure a current flowing through the power-supply-side line during execution of the single sequential operation mode by the control device.

Methods and apparatus for detecting a zero inductor current to control switch transitions for a power converter. An example method includes outputting a first voltage and a first current, receiving the first voltage and output a second voltage into an input of a comparator, when the second voltage is above a third voltage, outputting a first output voltage, when the second voltage is below the third voltage, outputting a second output voltage, determining when the first current is zero based the output of the comparator, enabling a set of switches based on when the first current is zero.

Methods and apparatus for detecting a zero inductor current to control switch transitions for a power converter. An example method includes outputting a first voltage and a first current, receiving the first voltage and output a second voltage into an input of a comparator, when the second voltage is above a third voltage, outputting a first output voltage, when the second voltage is below the third voltage, outputting a second output voltage, determining when the first current is zero based the output of the comparator, enabling a set of switches based on when the first current is zero.

An amplification interface includes first and second differential input terminals, first and second differential output terminals providing first and second output voltages defining a differential output signal, and first and second analog integrators coupled between the first and second differential input terminals and the first and second differential output terminals, the first and second analog integrators being resettable by a reset signal. A control circuit generates the reset signal such that the first and second analog integrators are periodically reset during a reset interval and activated during a measurement interval, receives a control signal indicative of offsets in the measurement sensor current and the reference sensor current, and generates a drive signal as a function of the control signal. First and second current generators coupled first and second compensation circuits to the first and second differential input terminals as a function of a drive signal.

A method for identifying consumer phase connectivity in low-voltage distribution network based on voltage association characteristics is provided. The specific steps thereof are: first, acquiring users to be identified and voltage time series data of three-phase buses on the low-voltage side of the low-voltage distribution network where the users to be identified are located; then, calculating voltage time series curve correlation coefficients among the users, and classifying a user having the maximum voltage time series curve correlation value with respect to the user into one category to form a user category set; then, based on the user classification, determining an initial consumer phase connectivity according to voltage association characteristics between the users and the three-phase buses on the low-voltage side of the low-voltage distribution network; finally, verifying the initial consumer phase connectivity according to the voltage association characteristics among the users to obtain a final consumer phase connectivity identification result.

A pulse voltage generator calculates a corrected pulse voltage application time. The pulse voltage generator also outputs, for the duration of the corrected pulse voltage application time, a voltage vector closest to a rotor phase from among twelve voltage vectors as a voltage vector command. A current detector detects three-phase output currents of a power converter, which are obtained when first to sixth switching elements of the power converter are turned on or off on the basis of the voltage vector command. A three-phase/two-phase converter converts the three-phase output currents to two-phase output currents to output d-axis current. When the d-axis current after the corrected pulse voltage application time has elapsed becomes less than or equal to a demagnetization determination threshold value, a demagnetization determiner determines that demagnetization occurs in a permanent magnet of a rotor of a motor.