An electronic circuit includes a switch coupled between an input terminal intended to receive a first voltage and an output terminal coupled to a decoupling capacitor and intended to also be coupled to a load. A comparison stage is configured to compare the first voltage and a second voltage that is present at the output terminal. A first adjustment stage is configured to limit a positive inrush current flowing between the input terminal and the output terminal and a second adjustment stage is configured to limit a negative inrush current flowing between the output terminal and the input terminal. A control circuit is configured to activate either the first adjustment stage or the second adjustment stage as a function of a result of the comparison.

A system may include a relay device that includes armatures associated with phases of voltage signals. The system may also include relay coils, such that each relay coil may receive a respective voltage that magnetizes a respective relay coil, thereby causing the respective armature to move from a respective first position to a respective second position. The system may also include a control system that receive an indication that a fault condition is present, identify a first phase of the phases of voltage signals that is expected to be the next phase of the phases to cross zero, and send a signal to the relay device in response to identifying the first phase. The signal is configured to cause a first relay coil of the relay coils to energize or deenergize.

A precharge resistor protection apparatus including a sensing unit configured to measure a battery voltage applied to both ends of a battery cell included in the battery pack and a precharge current flowing in the precharge resistor, and a processor operably coupled to the sensing unit. The processor calculates a first power estimated as being supplied to the precharge resistor and a second power supplied to the precharge resistor during a driving time of the precharge circuit unit by using at least one of a capacitance of a capacitor connected to both ends of the battery pack, the battery voltage and the precharge current, compares a reference power range according to the first power with the second power, and controls an operation state of the precharge relay based on the comparison result.

A method of protecting a power transformer including: monitoring an external fault indication signal; carrying out locally a fault determination; carrying out locally an inrush current determination; and issuing a final trip signal to protect the power transformer if the external fault indication signal identifies that a fault has occurred and the locally carried out fault determination confirms that a fault has occurred; or the external fault indication signal identifies that a fault has occurred and the locally carried out fault determination identifies that no fault has occurred but after a predetermined delay the locally carried out inrush current determination confirms the absence of an inrush current.

A method for minimizing inrush current of at least two electrical devices (211-219), the method being characterized in that it comprises the steps of: forming (1001) a network, managed by a host (420), of at least two inrush current controllers (500) each selectively controlling power supply to an associated electrical device (211-219); for each inrush current controller (500) defining, by the host (420), and applying (1002) a time delay value specified per device; setting (1003), in each inrush current controller (500), the respective delay value as a time delay between a request to supply the associated electrical device (211-219) with power and actually supplying it with power; wherein the delay value differs between the at least two inrush current controllers (500).

A system for protecting a transformer is provided. The system includes an inductor electrically disposed between the transformer and a load powered by the transformer, and a resistor electrically disposed in parallel with the inductor between the transformer and the load.

Described is a system that includes a solid-state switch in series with a battery and a controller. The system also includes a capacitor coupled between a source and a gate of the solid-state switch and a resistor coupled between the gate of the solid-state switch and ground. The solid-state switch gradually transitions from an open state to a closed state over a time constant of the capacitor and the resistor upon application of power from the battery to the solid-state switch. The system further includes a first switching device that controls the application of power from the battery to the solid-state switch. Additionally, the system includes a second switching device that provides a discharge path of the capacitor upon completion of a task by the controller.

A bidirectional switch and a method of the bidirectional switch including, a first enhancement mode n-channel metal oxide semiconductor field effect transistor (n-MOSFET) and a second n-MOSFET electrically connected in a common source configuration. The emitter of an insulated gate bipolar transistor (IGBT) is further electrically connected to the common sources of the n-MOSFET. A control board regulates a first operation of the IGBT and an operation of the first field effect transistor. The control board additionally receives at least one measured characteristic, from a sensor and determines the measured characteristic is below a predetermined threshold. The control board then regulates an operation of the second field effect transistor and a second operation of the IGBT.

A method of operating a switching device in a system. The method includes monitoring a voltage; operating the system at each of a plurality of system configurations; and, for each of the system configurations and a predetermined same opening angle relative to a reference angle of the monitored voltage, determining a suitable closing angle relative to the reference angle and storing information about the determined suitable closing angle in association with the system configuration in a database. The method then includes, determining a system configuration in the system; at the predetermined same opening angle, opening the switching device; from the database, obtaining a closing angle of the determined suitable closing angles, wherein the system configuration with which the obtained closing angle is associated in the database corresponds to the determined system configuration; and at the obtained closing angle, closing the switching device.

A start-up method for reducing inrush current to a transformer when closing a switching device. The switching device includes three single-pole operated current interrupting means. The method includes monitoring a voltage. The method includes, for each of a sequence of iterations: at a same opening angle relative to a reference angle of the voltage, starting an opening sequence of the switching device; at a closing angle relative to the reference angle, which is shifted in relation to the closing angle of all other iterations in the sequence, starting a closing sequence of the switching device; and obtaining an indication of the overall inrush current resulting from the closing. The method includes selecting for future use with the opening angle, the closing angle of one of the iterations in which the overall inrush current is relatively low when compared with the other iterations of the sequence.