Multiple relays are connected in parallel by including one or more semiconductor devices connected across the relay contacts. The semiconductor devices are triggered to conduct and shunt transient currents during the opening and closing of the relay contacts to protect the relay contacts from overcurrent and to eliminate arcing during relay switching. This permits a combination of smaller relays to replace a larger and more expensive relay in applications that require switching of large load currents.

A device for controlling a pre-charge current generated when electrically connecting a first terminal and a second terminal, according to one embodiment of the present invention, may comprise: a switch for controlling a magnitude of a current flowing between the first terminal and the second terminal; a first resistor for generating a base voltage of a first transistor in proportion to a magnitude of the pre-charge current flowing between the first terminal and the second terminal; the first transistor for limiting the magnitude of the pre-charge current when a voltage generated by the first resistor is equal to or greater than a predetermined threshold voltage; a photocoupler for receiving, in a state insulated from a first power source, an optical signal from the first power source and supplying power; a capacitor charged by the power supplied by the photocoupler; a second transistor for controlling the magnitude of the pre-charge current on the basis of a charging voltage of the capacitor; and a second resistor for controlling an operating time of the second transistor along with the capacitor.

Embodiments of the invention provide for a drop-in solid-state relay replacement for current standard relays. The drop-in solid-state relay may comprise receiving an input power and actuating at least one transistor to provide power to operational equipment. In some embodiments, an optical isolator may be disposed at an output driver stage of the relay circuit to provide electrical isolation between the input stage and the output stage. The drop-in solid-state relay may provide low input voltage, low heat, no noise, and not produce fly-back.

A device for controlling a pre-charge current generated when electrically connecting a first terminal and a second terminal, according to one embodiment of the present invention, may comprise: a switch for controlling a magnitude of a current flowing between the first terminal and the second terminal; a first resistor for generating a base voltage of a first transistor in proportion to a magnitude of the pre-charge current flowing between the first terminal and the second terminal; the first transistor for limiting the magnitude of the pre-charge current when a voltage generated by the first resistor is equal to or greater than a predetermined threshold voltage; a photocoupler for receiving, in a state insulated from a first power source, an optical signal from the first power source and supplying power; a capacitor charged by the power supplied by the photocoupler; a second transistor for controlling the magnitude of the pre-charge current on the basis of a charging voltage of the capacitor; and a second resistor for controlling an operating time of the second transistor along with the capacitor.

An arc extinguishing power device driving apparatus and an arc extinguishing apparatus of the present disclosure belong to the electrical field, and are particularly an arc extinguishing power device driving apparatus applicable to an electronic arc extinguishing apparatus for driving a power device. The power device that needs to be driven is connected in parallel to a mechanical switch that requires arc extinguishing, and includes a first voltage detection switch. An input end of the first voltage detection switch is connected to two ends of the power device. The first voltage detection switch is connected in series in a driving loop of the power device. The first voltage detection switch is turned on when detecting that there is a potential difference between the two ends of the power device. A driving signal is transferred to the power device by using the first voltage detection switch, to drive the power device to be turned on. The first voltage detection switch is a semi-controllable switch, or a fully-controllable switch whose threshold is less than an on-state voltage of the power device. The present disclosure has advantages of no need of a semiconductor device with a high withstand voltage, real-time detection on disconnection of a mechanical switch, and low driving energy consumption.

The invention relates to a capacitive coupling-type arc-extinguishing circuit and an apparatus. The capacitive coupling-type arc-extinguishing circuit includes a thyristor which is connected to two ends of a mechanical switch in parallel, where a driving signal for driving the thyristor to switch on is transferred from a main loop of the thyristor to a control electrode of the thyristor by using a capacitor; and a driving signal loop of the control electrode of thyristor is connected to at least an electronic switch. The capacitive coupling-type arc-extinguishing circuit and the apparatus have the advantages of the good arc-extinguishing effect, and high reliability. The apparatus includes a control circuit connected with the electronic switch of capacitive coupling-type arc-extinguishing circuit, have the advantage of short conduction time of the thyristor.

The invention relates to a current-feedback electronic arc-extinguishing apparatus suitable for implementing arc extinguishing on a mechanical switch. The current-feedback electronic arc-extinguishing apparatus includes a power semiconductor device which is connected to a mechanical switch in parallel, and a power supply circuit, where a main loop of the power semiconductor device is connected to a current sensor for detecting whether the mechanical switch is switched off; an output signal of the current sensor is connected to a control circuit, and a control port of the power semiconductor device is connected to the control circuit; the power supply circuit is connected to the control circuit, and the power supply circuit supplies power to the control circuit; and when the current sensor detects that the mechanical switch is switched off, the control circuit controls the power semiconductor device to cut off.

Switching device (1) for operating at least one load, comprising at least one switching unit (7; 8; 9), which switches a tapped current phase (L) to a load (2-1; 2-2; 2-3) connectable to the switching unit (7; 8; 9) to supply said load with current and which has a measurement unit (7C; 8C; 9C) which measures a current phase progression of the at least one current phase (L); a local control unit (18), which after receiving a control command from an external control system (24) actuates a semiconductor switch (7B; 8B; 9B) of the switching unit (7; 8; 9) in such a way that the semiconductor switch (7B; 8B; 9B) switches at a zero of the current phase (L) measured by the measurement unit (7C; 8C; 9C), and a local monitoring unit (20), which evaluates the current phase progression, measured by the measurement unit (7C; 8C; 9C), of the at least one current phase (L) to detect an operational deviation from a normal current supply to the associated load (2-1; 2-2; 2-3) connected to the switching unit (7; 8; 9), and reports any detected operational deviation.

An arc extinguishing power device driving apparatus and an arc extinguishing apparatus of the present disclosure belong to the electrical field, and are particularly an arc extinguishing power device driving apparatus applicable to an electronic arc extinguishing apparatus for driving a power device. The power device that needs to be driven is connected in parallel to a mechanical switch that requires arc extinguishing, and includes a first voltage detection switch. An input end of the first voltage detection switch is connected to two ends of the power device. The first voltage detection switch is connected in series in a driving loop of the power device. The first voltage detection switch is turned on when detecting that there is a potential difference between the two ends of the power device. A driving signal is transferred to the power device by using the first voltage detection switch, to drive the power device to be turned on. The first voltage detection switch is a semi-controllable switch, or a fully-controllable switch whose threshold is less than an on-state voltage of the power device. The present disclosure has advantages of no need of a semiconductor device with a high withstand voltage, real-time detection on disconnection of a mechanical switch, and low driving energy consumption.

Multiple relays are connected in parallel by including one or more semiconductor devices connected across the relay contacts. The semiconductor devices are triggered to conduct and shunt transient currents during the opening and closing of the relay contacts to protect the relay contacts from overcurrent and to eliminate arcing during relay switching. This permits a combination of smaller relays to replace a larger and more expensive relay in applications that require switching of large load currents.