A digital signal input circuit including an isolating circuit and a voltage determining circuit is presented, where a first port of an input end of the isolating circuit receives a digital signal, an output end of the isolating circuit outputs the digital signal, and when the isolating circuit is open, the isolating circuit is configured to output a first level, or when the isolating circuit is closed, the isolating circuit is configured to output a second level; and the voltage determining circuit is configured to determine, according to a level of the digital signal, whether the isolating circuit is open or closed. According to the digital signal input circuit, the voltage determining circuit determines a level of a digital signal, thereby correctness of digital signal level conversion is increased.

A digital signal input circuit including an isolating circuit and a voltage determining circuit is presented, where a first port of an input end of the isolating circuit receives a digital signal, an output end of the isolating circuit outputs the digital signal, and when the isolating circuit is open, the isolating circuit is configured to output a first level, or when the isolating circuit is closed, the isolating circuit is configured to output a second level; and the voltage determining circuit is configured to determine, according to a level of the digital signal, whether the isolating circuit is open or closed. According to the digital signal input circuit, the voltage determining circuit determines a level of a digital signal, thereby correctness of digital signal level conversion is increased.

An overvoltage detection circuit coupled to an external power supply via a voltage supply line and comprising a transistor comprising first terminal coupled to the voltage supply line, second terminal coupled to the first terminal via a resistor, the second terminal coupled to a parasitic capacitor, the transistor configured to receive an overvoltage spike from the external power supply on the first terminal, and provide an output voltage on third terminal of the transistor to indicate detection of the overvoltage spike when it has a duration less than a time constant based on the resistor and the parasitic capacitor and amplitude that exceeds a threshold voltage of the transistor. The overvoltage detection circuit further comprises a monitor circuit configured to receive the output voltage from the transistor and provide a digital signal providing a notification of the detected overvoltage spike from the external power supply on the voltage supply line.

In order to reliably determine the supply voltages (U.sub.i) of the individual phases (L1, L2, L3) of a load (4) in a multiphase supply network (2), in particular a three-phase supply network, a measuring module (6) is provided and is used to determine the supply voltages (U.sub.i) from measuring voltages (U.sub.i,mess) with the aid of a matrix operation. The matrix operation is used, in particular, to compensate for potential differences or potential shifts between the measuring system and the supply network (2) without the need for hardware measures, for example a voltage transformer.

This disclosure relates generally to an energy metering assembly configured to measure current and voltage of a one or more primary conductors, the energy metering assembly comprising a core; a coil having a plurality of turns, the coil being positioned around the core when securing the core to the one or more primary conductors; a voltage sensor, the voltage sensor being configured to sense a voltage of a one or more primary conductors; and a controller coupled to the coil and the voltage sensor, the controller being configured to determine a voltage of the one or more primary conductors, determine a current of the one or more primary conductors, and responsive to determining the voltage and the current, determine the power carried by the one or more primary conductors.

Disclosed are a method and system for testing high-voltage ride-through of a photovoltaic inverter. The method for testing high-voltage ride-through of a photovoltaic inverter includes: connecting a board-to-board (BTB) circuit to a passive circuit in series, and connecting circuit breakers to the passive circuit to form an inverter test device; connecting one end of the inverter test device to an alternating current power supply, and connecting the other end of the inverter test device to a tested apparatus; and performing testing by adjusting a parameter of the passive circuit and a switching mode of the circuit breakers by means of the BTB circuit. According to the present disclosure, an influence of the device for testing high-voltage ride-through of a photovoltaic inverter on power supply voltage is eliminated, a requirement on supply of reactive power of the power supply is eliminated, applicability is better, and cost is lower.

There is provided a non-contact voltage measuring sensor (1) in which a detection probe (11) is configured with a leaf spring and in which, when an external force is applied, the detection probe (11) deforms winding in a direction in which a tension of the leaf spring acts.

Embodiments of the present disclosure relate to a multi-function circuit. The circuit comprises a low side circuit that is comprised with a first set of enhancement mode transistors. The half bridge circuit also includes a high side circuit that is comprised of a second set of transistors. Each of the enhancement mode transistors of the first set and second set of enhancement mode transistors are Gallium Nitride (GaN) transistors. In some embodiments, the GaN transistors are High Electron Mobility Transistors (HEMTs). In additional embodiments, the GaN transistors are configured and operated as saturated switches. In further embodiments, the half bridge circuit is designed as a discrete circuit. Additionally, each of the first set and second set of transistors, diodes, resistors, and all passive elements are discrete components arranged to form a half bridge circuit. In fact, the entire half bridge circuit is built from discrete components.

A detection circuit includes an under-voltage circuit. The under-voltage circuit includes a first GaN high electron mobility transistor (HEMT) configured to operate as both a voltage comparator and a voltage reference. The detection circuit can also include an over-voltage detection circuit. The over-voltage detection circuit includes a second GaN HEMT that is also configured to operate as both a voltage comparator and a voltage reference. Each of the under-voltage circuit and over-voltage circuit includes a GaN HEMT logic inversion element to provide electrical hysteresis. Also, the under-voltage detection circuit and the over-voltage detection circuit are configured to provide outputs to a single power good terminal. The first GaN HEMT can be configured to use its gate source threshold voltage for voltage comparison and reference. The second GaN HEMT can be configured to use its gate source threshold voltage for voltage comparison and reference.

A power quality analysis system is configured to carry out a power quality analysis in an electrical environment. The system comprises one or more power consuming units each electrically connected to a main power supply by a multiconductor (multicore) cable and one or more power quality sensors configured to provide one or more power quality analysis measurements. The one or more power quality sensors are clamp-on power quality sensors configured to provide one or more power quality analysis measurements when the clamp-on power quality sensors are clamped onto the outside of or arranged in the proximity of the multiconductor cable. The clamp-on power quality sensors are configured to provide the one or more power quality analysis measurements without being electrically connected to any of the conductors of the multiconductor cable.