A high voltage DC (HVDC) system can include a generator configured to output alternating current (AC), a rectifier connected to the generator via AC phase lines, the rectifier configured to convert the AC to DC to output the DC to DC feeder lines, and a crowbar system. The crowbar system can include a switch module operatively connected to the AC phase lines to prevent AC from flowing to the rectifier in a cutoff state. The crowbar system can be configured to determine whether at least one cutoff condition exists. The at least one cutoff condition can be or include one or more of a DC overcurrent downstream of the rectifier, a DC overvoltage downstream of the rectifier, an AC overcurrent from the generator, or an arc fault. The crowbar system can be configured to control the switch module to the cutoff state if the at least one cutoff condition exists.

A power supply with lightning protection includes a surge voltage suppression apparatus, an electromagnetic interference control circuit, a surge current bypass apparatus, an active bridge rectifier circuit, a power factor correction circuit, and a DC-to-DC conversion circuit. The surge voltage suppression apparatus is used to increase a tolerance of a surge voltage for the power supply. The electromagnetic interference control circuit is coupled to the surge voltage suppression apparatus. The surge current bypass apparatus is used to increase a tolerance of a surge current for the power supply. The active bridge rectifier circuit is used to rectify an input voltage. The power factor correction circuit is used to adjust the rectified input voltage to provide an adjusted input voltage on a bulk capacitor. The DC-to-DC conversion circuit is used to convert the adjusted input voltage into a DC output voltage.

A semiconductor device according to related art has a problem that a clamp voltage that clamps an output voltage cannot adaptively vary in accordance with a power supply voltage, and it is thus not possible to reduce heating of a semiconductor chip to a sufficiently low level. According to one embodiment, a semiconductor device includes a drive circuit (10) that controls on and off of an output transistor (13) and an overvoltage protection circuit (12) that controls a conductive state of the output transistor (13) when an output voltage Vout reaches a clamp voltage, and the overvoltage protection circuit (12) has a circuit structure that sets the clamp voltage to vary in proportion to a power supply voltage VDD.

A power supply device is disclosed. A circuit board is disposed inside a conductive housing. A rectifying module is disposed on the circuit board and has primary and secondary sides. The grounding module includes a first grounding element, a second grounding element, and a fastening element. Two terminals of the first surge protection module are respectively electrically connected to the primary side and the first grounding element. Two terminals of the second surge protection module are respectively electrically connected to the secondary side and the second grounding element. The second grounding element and the first grounding element are not directly connected. The fastening element passes through the conductive housing, the circuit board, the first grounding element, and the second grounding element so that the conductive housing, the first grounding element, and the second grounding element are electrically connected to one another.

A power supply includes a power converter, a protection circuit, and a control circuit. The protection circuit includes an input for receiving an input voltage, an output for providing an output voltage to the power converter, a first switching device coupled in a current path between the input and the output, and a second switching device coupled across the first switching device. The control circuit is configured to sense the input voltage and the output voltage, in response to the output voltage exceeding a first defined threshold, turn off the first switching device and turn on the second switching device to supply power to the power converter, and in response to the input voltage exceeding a second defined threshold, turn off the second switching device to disconnect the power source from the power converter. Other example power supplies and protection circuits are also disclosed.

An LED driving device includes a converter module configured to receive an input voltage and generate an output voltage for driving a plurality of LEDs. A surge protection module is electrically connected to the converter module. A case holds the converter module and the surge protection module, and provides electrical coupling therebetween.

Protection of an electric motor drive controller from a transient voltage is described herein. The transient voltage is provided by an alternating current (AC) power line that includes a line conductor, a neutral conductor, and a ground conductor. The transient voltage protection system includes a first stage protection device coupled to an input of a rectifier of the motor drive controller. The first stage protection device is configured to suppress the transient voltage to prevent damage to the motor drive controller. The transient voltage protection system also includes a second stage protection device coupled between the rectifier and an inverter of the motor drive controller. The second stage protection device is configured to further suppress the transient voltage to prevent damage to the inverter.

An external power supply system for spindles is revealed. The external power supply system includes a tool holder, a rectifier circuit, an overvoltage protection circuit. and a buck/boost converter. The tool holder receives an external power source of a spindle while the rectifier circuit converts the external power source into a rectified output signal with a power factor through step-down transformation. The overvoltage protection circuit is used to check whether the rectified output signal is larger than an overvoltage signal for outputting an operating potential or a non-operating potential. The buck/boost converter is used for receiving the rectified output signal with the power factor and converting the rectified output signal to an output voltage according to the power factor. Then the output voltage is provided to a load of a low voltage power supply, a high voltage power supply, or a constant voltage power supply.

The problem to be solved is to provide a system and a method to protect the regulator rectifiers from the reverse voltage condition and the short circuit condition, and the problem is solved in the present invention by a system and a method that use a protection device including a control unit that receives an input from the circuit based on the reverse voltage condition and the short circuit condition, and based on the existence of at least one of the condition or a combination thereof, the control unit switches a switching unit from an ON state to an OFF state, thereby breaking the circuit between the regulator rectifier device and the load section, thus protecting the regulator rectifier device.

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.