A Static Electrostatic Generator (SEG) is disclosed which produces static charges at high voltage and low current. The SEG is capable of generating positive or negative charges on a metal sphere by reversing the polarity of a DC source. The conversion efficiency of the system is about 47% and its design is simple, lightweight, and easy to manufacture. The SEG is a static device and no mechanical movement is required to produce charges. Also, the design is easily scalable.

A Static Electrostatic Generator (SEG) is disclosed which produces static charges at high voltage and low current. The SEG is capable of generating positive or negative charges on a metal sphere by reversing the polarity of a DC source. The conversion efficiency of the system is about 47% and its design is simple, lightweight, and easy to manufacture. The SEG is a static device and no mechanical movement is required to produce charges. Also, the design is easily scalable.

An embodiment buck converter control circuit comprises an error amplifier configured to generate an error signal based on a feedback signal and a reference signal, a pulse generator circuit configured to generate a pulsed signal having switching cycles set to high and low as a function of the error signal, a driver circuit configured to generate a drive signal for an electronic switch of the buck converter as a function of the pulsed signal, a variable load, connected between two output terminals of the buck converter, configured to absorb a current based on a control signal, and a detector circuit configured to monitor a first signal indicative of an output current provided by the buck converter and a second signal indicative of a negative transient of the output current, and verify whether the second signal indicates a negative transient of the output current.

An embodiment buck converter control circuit comprises an error amplifier configured to generate an error signal based on a feedback signal and a reference signal, a pulse generator circuit configured to generate a pulsed signal having switching cycles set to high and low as a function of the error signal, a driver circuit configured to generate a drive signal for an electronic switch of the buck converter as a function of the pulsed signal, a variable load, connected between two output terminals of the buck converter, configured to absorb a current based on a control signal, and a detector circuit configured to monitor a first signal indicative of an output current provided by the buck converter and a second signal indicative of a negative transient of the output current, and verify whether the second signal indicates a negative transient of the output current.

An elevator includes an elevator motor; a motor drive for the elevator motor having a frequency converter including a rectifier bridge, an inverter bridge and a DC link in between, which frequency converter is controlled via a controller, the rectifier bridge being connected to AC mains via three feed lines including chokes, and the rectifier bridge being realised via controllable semiconductor switches; a contactor being located between the feed lines and AC mains; and a backup power supply at least for emergency drive operation. An emergency control is associated with the motor drive, which emergency control is configured to perform an automatic emergency drive. The emergency control is connected to a manual drive circuit having a manual drive switch for a manual rescue drive. The elevator includes a motion sensor connected to the emergency control, whereby the emergency control is configured to activate a brake and/or gripping device of the elevator in case the car speed during a manual rescue drive exceeds a predetermined threshold value.

A multi-phase parallel converter can include: sampling circuits corresponding to power stage circuits to form a plurality of phases of the multi-phase parallel converter, where each sampling circuit samples an inductor current of a corresponding power stage circuit, and generates a sense signal; a current-sharing circuit that generates a current-sharing control signal according to a superimposed signal that is generated by adding the sense signal to a bias voltage signal; switching control circuits corresponding to the power stage circuits, where each switching control circuit receives the current-sharing control signal, and controls a switching operation of a corresponding power stage circuit; and a bias voltage generator that generates the bias voltage signal to gradually increase/decrease when a selected phase is to be disabled/enabled.

A driving circuit providing a driving signal at a driving terminal to drive a power switch. The driving signal has a first driving period and a second driving period. Both the first driving period and the second driving period have a first driving time interval. The driving circuit has a first equivalent on resistor established during the first driving time interval and located between a first voltage node and the driving terminal. The first equivalent on resistor has a first equivalent on resistance during the first driving time interval of the first driving period and has a second equivalent on resistance during the first driving time interval of the second driving period. The first equivalent on resistance and the second equivalent on resistance are not equal.

The application describes a method for operating an electrolyzer to generate hydrogen from water using an electrolysis reaction, supplied with power from an AC grid via an actively controlled rectifier circuit. The method includes operating the electrolyzer in a normal operating mode with an input voltage U.sub.EI above a no-load voltage U.sub.LL with predominantly ohmic behavior, operating the electrolyzer in a standby operating mode with an input voltage U.sub.EI below the no-load voltage U.sub.LL with predominantly capacitive behavior, and transitioning from the standby operating mode to the normal operating mode during a first transition duration Δt.sub.1, wherein the first transition duration Δt.sub.1 is reduced by keeping the input voltage U.sub.EI at the electrolyzer input during the standby operating mode above a first voltage threshold value U.sub.TH,1 different from 0 V. The application furthermore describes a connection circuit, an actively controlled rectifier circuit and an electrolysis system for performing the method.

Provided is a control unit of a power conversion device configured to select, in each first set cycle, a first target switching element and a second target switching element from a plurality of switching elements connected in parallel to each other. The control unit performs control so that, at a time of a turn-on operation of a switching circuit, a turn-on start time of the first target switching element is earlier by a first set time period than a turn-on start time of another switching element that is not the first target switching element. The control unit performs control so that, at a time of a turn-off operation of the switching circuit, a turn-off start time of the second target switching element is later by a second set time period than a turn-off start time of another switching element that is not the second target switching element.

Provided is a control unit of a power conversion device configured to select, in each first set cycle, a first target switching element and a second target switching element from a plurality of switching elements connected in parallel to each other. The control unit performs control so that, at a time of a turn-on operation of a switching circuit, a turn-on start time of the first target switching element is earlier by a first set time period than a turn-on start time of another switching element that is not the first target switching element. The control unit performs control so that, at a time of a turn-off operation of the switching circuit, a turn-off start time of the second target switching element is later by a second set time period than a turn-off start time of another switching element that is not the second target switching element.