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.

A system includes a dry contact with a first pair of switchable electrodes, a wet contact with a second pair of switchable electrodes, an arc suppressor, and a controller circuit operatively coupled to the arc suppressor and the first and second pairs of switchable electrodes. The controller circuit is configured to detect a failure of the wet contact and determine a stick duration associated with the first pair of switchable electrodes. The stick duration is based on a duration between an instance when a coil of the dry contact is deactivated and an instance of separation of the first pair of switchable electrodes during deactivation of the coil. The controller circuit generates, in-situ and in real-time, health assessment for the first pair of switchable electrodes based on a comparison of the determined stick duration with an average stick duration associated with a window of observation.

A switching apparatus for an electric grid includes first and second electric terminals, each having first and second electric branches having a plurality of switching devices. The first electric branch includes a first switching device switchable between open and closed states, which is driven by a current flowing along said first switching device and without receiving an external control signal or an external power supply, said first switching device switching from said closed state to said open state, when the current flowing along said switching apparatus exceeds a corresponding predefined threshold value or when the changing rate of the current flowing along said switching apparatus exceeds a corresponding predefined threshold value or upon a combination of these two conditions. A second switching device is connected in series with the first switching device and is switchable between closed and open states upon receiving a corresponding input control signal.

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.

Provided is a current limiting circuit (30) configured to: before release of a touch between a second contact (20b) provided at a position where a terminal (11a) on a power receiving side in which a current flows at supply of DC power in an electrode that supplies the DC power touches before touching a first contact (20a) provided for the electrode at supply of the DC power and the terminal (11a), decrease the current flowing into the terminal (11a) through the second contact (20b); and avoid flowing a current in a case where the terminal (11a) is touching the first contact (20a), and decrease the current flowing into the terminal (11a) through the second contact (20b) only in a case where the terminal (11a) is touching the second contact (20b).

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 power contact electrode plasma therapy circuit includes a pair of terminals adapted to be connected to a set of switchable contact electrodes of a power contact. A plasma ignition detector is configured to detect an electrical parameter over the switchable contact electrodes indicative of the formation of plasma between the switchable contact electrodes and output a plasma ignition signal based on the electrical parameter as detected. A plasma burn memory is configured to receive and store the plasma ignition signal. A controller circuit is configured to receive from the plasma burn memory the plasma ignition signal, start a time based on receipt of the plasma ignition signal, and upon the timer meeting a time requirement, output a plasma extinguish command. A plasma extinguishing circuit, configured to bypass the pair of terminals upon receiving the trigger signal to extinguish the plasma between the switchable contact electrodes.

A switching apparatus includes first and second electric terminals, and first and second electric branches comprising one or more switching devices. The second electric branch is electrically connected in parallel with said first electric branch between said first and second electric terminals. The switching apparatus comprises a current blocking circuit adapted to block a current along said second branch. The current blocking circuit includes a first switching device of solid-state type and a first electronic circuit electrically connected in parallel to said first switching device of solid-state type. The switching apparatus further comprises a current limiting circuit adapted to limit a current flowing along said second electric branch. Said current limiting circuit is electrically connected in series with said current blocking circuit and it includes a second switching device of solid-state type and a second electronic circuit electrically connected in parallel to said second switching device of solid-state type.

A system includes a contactor operatively connected to a coil for actuating the contactor to open and close a circuit. A pass element includes a source, a drain, and a gate, wherein the drain is electrically connected to the coil, and wherein the coil is in series between the pass element and ground. A voltage source is connected to the source of the pass element to pass current into the coil when the pass element is in a pass state. A current source control circuit with economizer is operatively connected to the gate of the pass element. A delay circuit is operatively connected to the current source control circuit with economizer and to a command line to command a lower current for holding the contactor closed after a delay has expired for the contactor to transition.

A flexible circuit breaker includes at least two semiconductor switches, at least one input and at least two outputs. Each of the at least two semiconductor switches can carry a defined current, and each of the at least two semiconductor switches is monitored individually in relation to the current flowing therethrough, the first output is assigned to a first semiconductor switch, where by a selection using a selection device on the flexible circuit breaker, one can select whether the current flowing through a second semiconductor switch is assigned to the second output or the first output.