Gate control of power semiconductor devices using reduced gate drivers is disclosed. A circuit breaker may include a multitude of transistors, such as insulated gate bipolar transistors (IGBTs), connected in series with one another. Each transistor may be connected to a respective gate resistor. Diodes may be connected between various gate resistors. One or more resistor-capacitor (RC) snubber circuits may be provided in parallel with one or more of the transistors. Likewise, one or more metal-oxide varistors (MOVs) may be connected in parallel to one or more of the transistors. A gate driver (e.g., a single gate drive) may be connected to the one or more diodes and an emitter of at least one of transistors.

An electrical unit may include a current controller including an electrical regulator, a control circuit connected to a first input of the electrical regulator, a timer connected to a second input of the electrical regulator, and/or a turn-off circuit including a turn-off switch. The current controller may be configured to provide a first output signal in a first mode and a second output signal in a second mode. The current controller may be configured to transition from the first mode to the second mode based on a timer output of the timer. An electrical system may include an electrical unit and or a switch connected to the electrical unit. The switch may include a coil. The electrical unit may be configured to provide the first output signal to the coil in the first mode and provide the second output signal to the coil in the second mode.

Described herein is a switching apparatus for low or medium voltage electric grids, which includes one or more electric poles. Each electric pole includes: an outer casing defining an internal volume of the electric pole; a fixed contact assembly accommodated in the internal volume of the electric pole and including a fixed contact member extending along a longitudinal axis of the electric pole; at least one movable contact assembly accommodated in the internal volume of the electric pole; an actuation member accommodated in the internal volume of the electric pole and arranged coaxially and externally relative to the fixed contact member, so that the fixed contact member passes through the actuation member along the longitudinal axis. The actuation member is slidingly movable along the fixed contact member. When moving between the first and second actuation positions, the actuation member transiently couples to each trip mechanism to actuate the trip mechanism.

A direct current circuit breaker, including: n in number circuit breaker modules connected in series, one energy-absorbing and voltage-limiting module connected in parallel to the n in number circuit breaker modules, and a trigger module. The n in number circuit breaker modules each includes a mechanical switch and a commutation branch circuit which are connected in parallel; each commutation branch circuit includes a charging commutation module and a commutation capacitor which are connected in series; the charging commutation module is configured to charge up the commutation capacitor and produce reverse current to cut off the mechanical switch; the one energy-absorbing and voltage-limiting module is configured to absorb energy stored in inductive elements of power systems after a fault current is cut off, so as to limit voltage and protect the mechanical switch, and n is a positive integer greater than or equal to 1.

A direct current circuit breaker comprises a mechanical relay in a first supply line configured to conduct electrical current during steady-state operation and an auxiliary relay assembly in parallel with the mechanical relay to define an auxiliary breaker path for conducting electrical current during transient operation of the circuit breaker. The auxiliary relay assembly comprises a power-semiconductor circuit configured for selective current conduction and for bidirectional current blocking when in a non-conductive state. There is also a controller configured to (i) activate the power-semiconductor circuit to conduct in response to a command signal to stop transfer of the electrical power, in order to provide a zero voltage condition under which the mechanical relay is to deactivate; (ii) deactivate the mechanical relay when current is being conducted through the auxiliary breaker path; and (iii) deactivate the power-semiconductor circuit after the mechanical relay is deactivated to stop the transfer of the power.

A series Z-source circuit breaker including a semiconductor switch that breaks source power being provided to a load in response to overcurrent. An electromechanical switch is electrically coupled in parallel with the semiconductor switch, a first capacitor is electrically coupled to an output side of the semiconductor switch, a second capacitor is electrically coupled in parallel with the semiconductor switch, and a delay circuit is electrically coupled in series with the first capacitor. The semiconductor switch is in an open position and the electromechanical switch is in a closed position when overcurrent is not present. Upon detection of overcurrent the semiconductor switch is closed, the electromechanical switch is opened and the delay circuit is controlled to delay when reverse bias current is provided from the first capacitor to the semiconductor switch to prevent source power from being provided to the load to give the electromechanical switch time to open.

An arrangement for detecting arcs in a low-voltage circuit has at least one voltage sensor for periodically determining voltage values of the low-voltage circuit and at least one current sensor for periodically determining current values of the low-voltage circuit. A first control unit is connected to the voltage sensor and the current sensor, has a processor, and is configured in such a way that the presence of a switch arc is determined on the basis of the determined voltage values and current values. A switch arc detection signal is output if a switch arc is determined to be present.

A vacuum interrupter having a structure to trap running cathode tracks is disclosed. The interrupter includes a first electrode assembly and a second electrode assembly, at least one of which is moveable. The interrupter also includes a sidewall having a longitudinal axis. One or more trench structures are formed in at least one of the electrode assemblies. Each trench structure has an opening that faces the other electrode assembly in a direction that is parallel to the longitudinal axis, to trap the running cathode tracks to prevent them from getting close to the sidewall.

This application discloses a photovoltaic direct-current breaking apparatus, including a positive connection terminal and a negative connection terminal for connecting a photovoltaic string and a photovoltaic energy converter, a first diode, a first switch, a convector circuit, and an energy absorption circuit, where the first switch, the convector circuit, and the energy absorption circuit are connected in parallel. The convector circuit can effectively avoid arc discharge and ablation generated when the first switch cuts off a direct-current circuit between the photovoltaic string and the photovoltaic energy converter. The first diode can effectively bypass energy stored by an energy storage device in the photovoltaic energy converter, helping reduce required specifications of a semiconductor device in the convector circuit. The energy absorption circuit can also effectively reduce required specifications of the semiconductor device and a varistor.

A switching device includes: a first terminal contact; a first fixed contact arranged at the first terminal contact; a contact bridge; a contact bridge carrier arranged at the contact bridge and having a barrier; a first movable contact arranged at the contact bridge; a second terminal contact; a second fixed contact arranged at the second terminal contact; a second movable contact arranged at the contact bridge; and a magnetic drive assembly including a coil and an armature, the armature being coupled to the contact bridge. The first fixed contact is in contact with the first movable contact in a switched-on state of the switching device. The first fixed contact is free of contact with the first movable contact in a switched-off state of the switching device. The second fixed contact is in contact with the second movable contact in the switched-on state of the switching device.