In an active converter that is connected to an electric machine, in which arresting circuits for activating a voltage arrest beginning at a first point in time are provided, and which is also configured for activating a load shedding reaction only when activation conditions are fulfilled beginning at a second point in time, the activation conditions include determining that the voltage arrest is still activated at the second point in time, that a voltage potential has not yet fallen below the first threshold value, and/or that a value that indicates a current flowing through at least one phase connection is above a third threshold value.

An integrated circuit includes a voltage regulating circuit in the form of only one transistor, or a group of several transistors in parallel, that are connected between first and second terminals configured to be coupled to an antenna. A control circuit operates to make the voltage regulating circuit inactive when a pulse generated by an electrostatic discharge event appears at one of the first and second terminals, regardless of the direction of flow of the pulse between the first and second terminals. An electrostatic discharge circuit is further provided to address the electrostatic discharge event.

An electric grid includes feed-ins, loads, and a distribution grid, which is arranged therebetween. The distribution grid comprises at least one busbar and at least one device for opening or closing a DC circuit. The at least one device includes an electric switch for opening or closing the DC circuit, a fault current detector, a trigger unit, a precharging device, and a control unit for automatically closing the electric switch after the precharging process. The electric switch opens the DC circuit via the trigger unit if a fault current is detected by the fault current detector, and the precharging device restores the voltage on the busbar prior to closing the electric switch.

A power control circuit includes an alternating current power supply module, a power module, and a controller. The power module includes a bridgeless power factor correction circuit. A sampling apparatus in the alternating current power supply module samples a current signal output by an alternating current power supply or the power module, and outputs an obtained sampled signal to the controller. The controller controls on and off of a switch element in the alternating current power supply module based on the received sampled signal, and the controller switches off the switch element when the sampled signal includes a lightning surge signal. In addition, the controller is further configured to perform current metering on the sampled signal.

A device is for opening or closing a DC circuit with at least one busbar. The device includes an electric switch for opening or closing the DC circuit; a fault current detector; a trigger unit and a precharging device. The electric switch opens the DC circuit via the trigger unit upon a fault current being detected by the fault current detector. Further, the precharging device restores the voltage on the busbar prior to closing the electric switch. The device further includes a control unit for automatically closing the electric switch after the pre-charging process.

An electrical network includes feed-in devices, loads, and a distribution grid, which is arranged therebetween and comprises at least one busbar and at least one device for opening or closing a DC circuit. The at least one device includes: an electric switch for opening or closing the DC circuit; a fault current detection device; a trigger unit; a precharging device; and a control unit for automatically closing the electric switch after the precharging process. The electric switch opens the DC circuit via the trigger unit if a fault current is detected by the fault current detector, and the precharging device restores the voltage on the busbar prior to closing the electric switch. Multiple loads can be individually electrically separated via a respective electromechanical switch, and multiple loads can be electrically separated as a group via the at least one device.

An overvoltage recovery circuit (ORC), a controller for an HVAC system and an HVAC system are disclosed herein. In one embodiment, the ORC includes: (1) a first supply voltage terminal connected to a first voltage supply, (2) a second supply voltage terminal connected to a second voltage supply, (3) interruption circuitry including a switch and a trip terminal connected to the second supply voltage terminal and (4) detection circuitry connected to the first supply voltage terminal and the switch of the interruption circuitry, the detection circuitry configured to operate the switch in response to an overvoltage condition at the first supply voltage terminal.

A circuit is described that includes a rectifier configured to rectify a DC output from an AC input, a sensing unit configured to detect a voltage level of the DC output, and a control unit configured to control the rectifier based on the voltage level of the DC output. The control unit is configured to control the rectifier output by at least controlling the rectifier to rectify the DC output from the AC input if the voltage level of the DC output does not indicate an overvoltage condition at the circuit. In addition, the control unit is configured to control the rectifier based on the voltage level of the DC output by at least controlling the rectifier to shunt current from the AC input if the voltage level of the DC output does indicate the overvoltage condition.

An overvoltage recovery circuit (ORC), a controller for an HVAC system and an HVAC system are disclosed herein. In one embodiment, the ORC includes: (1) a first supply voltage terminal connected to a first voltage supply, (2) a second supply voltage terminal connected to a second voltage supply, (3) interruption circuitry including a switch and a trip terminal connected to the second supply voltage terminal and (4) detection circuitry connected to the first supply voltage terminal and the switch of the interruption circuitry, the detection circuitry configured to operate the switch in response to an overvoltage condition at the first supply voltage terminal.

According to some aspects of the present disclosure, isolated power supplies and corresponding control methods are disclosed. Example isolated power supplies include a transformer, at least one power switch coupled to the transformer, a controller, an output terminal, and a feedback circuit coupled to the output terminal to sense the output voltage and compare the sensed output voltage to a voltage reference. The power supplies include a fault detection circuit to sense the output voltage, compare the sensed output voltage to a fault reference, and modify a feedback signal when the sensed output voltage exceeds the fault reference. The power supplies also include a single isolation device coupled between the feedback circuit and the controller. The controller is operable to control the power switch based on the feedback signal and to detect a fault condition when a slew rate of the feedback signal exceeds a fault threshold slew rate value.