Systems and methods for measuring alternating current (AC) voltage of an insulated conductor (e.g., insulated wire) are provided, without requiring a galvanic connection between the conductor and a test electrode or probe. A non-galvanic contact (or non-contact) voltage measurement system includes a conductive sensor, an internal ground guard and a reference shield. A common mode reference voltage source is electrically coupled between the internal ground guard and the reference shield to generate an AC reference voltage which causes a reference current to pass through the conductive sensor. At least one processor receives a signal indicative of current flowing through the conductive sensor due to the AC reference voltage and the AC voltage in the insulated conductor, and determines the AC voltage in the insulated conductor based at least in part on the received signal.

The invention is based on an electrical current measuring device for measuring at least one alternating current, with at least one inductive coupling unit, which is intended to convert at least one electrical primary signal into at least one electrical secondary signal, and with a computing unit, which is intended to determine the primary signal from the secondary signal. The computing unit is intended to take into account at least one higher harmonic of the secondary signal when determining the primary signal.

The system comprises an electronic timer circuit in a housing. The system having an automatic voltage sensor, a handheld tool, and a tool storage location. The sensor eliminates the need for manual voltage selection. The handheld tool connects to the circuit via a USB cable and is storable about the housing. The tool processes data it receives from the circuit and displays various information to a user.

Systems and methods for measuring alternating current (AC) voltage of an insulated conductor (e.g., insulated wire) are provided, without requiring a galvanic connection between the conductor and a test electrode or probe. A non-galvanic contact (or non-contact) voltage measurement system includes a variable capacitance subsystem which operates to generate a variable capacitive voltage between an insulated conductor under test and earth ground. During measurement, the non-contact voltage measurement system varies the capacitance of the variable capacitance subsystem to change the impedance of a capacitive divider circuit between the insulated conductor under test and earth ground. By sequentially making two (or three) measurements across the variable capacitance subsystem, the AC voltage of the insulated conductor can be determined without requiring any galvanic connection to the insulated conductor. The determined AC voltage of the insulated conductor may then be presented to an operator and/or communicated to an external device.

A method of detecting states of an electrical load from an electrical signal. This involves first providing a mathematical model for the electrical signal. A sliding window can then be used to es-timate parameters of the model. In doing this, a plurality of windows are determined for the electrical signal, a window function is applied for each of the windows, and parameters of the model are determined by interpola-tion. The waveform can then be reconstructed from the determined para-meters and subtracted from the reconstructed waveform from the original signal to obtain a residual. State transitions can then be determined where a difference between the reconstructed waveform and the original signal exceeds a threshold. States are detected and determined as existing for the time period between successive state transitions. Methods of monitoring an electrical system using this approach are also described, as are electrical devices adapted to perform such methods.

A single handheld multimeter device includes two or more independent measurement channels that are completely electrically separated and independent from one another. Each measurement channel has its point of reference, typically configured to be coupled to the ground. Measurements by the two or more independent measurement channels can be conducted concurrently, and the measurement results of the two channels can be processed and displayed together.

Systems, devices, and methods for a high-voltage conversion circuit system comprising: an error detection and correction module configured to receive an analog input signal and a feedback signal and generate a correction signal; and an analog to pulse width modulation (PWM) module configured to receive the analog input signal and correction signal and generate a PWM output signal; where the generated PWM output signal is fed back to the error detection and correction module as said feedback signal.

A method for estimating a fundamental component of an AC voltage includes receiving a timely varying measurement signal of the AC voltage; parametrizing a fundamental component of the AC voltage; and determining parameters of the fundamental component based on minimizing a cost function. The fundamental component has a rated frequency, a variable amplitude and a variable phase shift. The cost function is based on an integral of a norm of a difference between the measurement signal and the parametrized fundamental component via a time horizon. The time horizon starts at an actual time point and goes back via a predefined length. The cost function includes a term based on a norm of the difference between a value of the fundamental component at the actual time point and a value of a previously estimated fundamental component at the actual time point, where the previously estimated fundamental component has been determined for a previous time point.

In accordance with an embodiment, a method of operating a switched-mode power converter includes measuring an input voltage of the switched-mode power converter; determining an on-time of a switch of the switched-mode power converter; determining an off-time of the switch of the switched-mode power converter; and determining an output voltage of the switched-mode power converter based on the measured input voltage, the determined on-time and the determined off-time. The output voltage includes a voltage at a first node having a DC path to a load path of the switch.

A combination of a conductor, such as a busbar, and a device for measuring the AC voltage in the conductor, which device includes: an insulation layer arranged on the conductor; a capacitor plate arranged on the insulation layer and configured to position the capacitor plate at a fixed distance from the conductor to form a first capacitor; a second capacitor arranged electrically between the capacitor plate and ground to provide a capacitive voltage divider with the first capacitor; and a voltage measurer for measuring the voltage at the capacitor plate, the voltage measurer including a frequency measurer for measuring the frequency of the voltage in the conductor and an AC voltage calculator for calculating the AC voltage in the conductor based on the capacities of the first and second capacitors, the measured voltage, and the measured frequency.