A method for limiting current in-rush in automotive lighting devices. By controlling the state of a switching circuit that is used to selectively connect a power supply to an automotive lighting device, the invention allows for selectively limiting the intensity of the current that is supplied to the lighting device. In accordance with preferred embodiments, this advantage is achieved by relying on electronic components that are nowadays used for different purposes.

A method for phase controlled energizing of a power transformer includes acquiring electrical voltage signal from a voltage sensing device connected to the power transformer. Determining a first characterizing data in the voltage signal within a pre-determined set of cycles at about an opening operation of a circuit breaker and determining a second characterizing data within the pre-determined set of cycles in the voltage signal subsequent to the opening operation of the circuit breaker. Estimating a level of magnetization of the core of the power transformer based on at least one of second characterizing data, and the first characterizing data and the second characterizing data. Operating the circuit breaker at a determined instant of switching based on the estimated level of magnetization for a phase controlled energizing of the power transformer by the circuit breaker.

A method and circuit for a power supply unit (PSU) suitable for use in an information handling system to detect an inrush current reaching an inrush current threshold, to fully turning off, by a control circuit of the PSU, a series transistor to block the inrush current, to transfer, while the series transistor is fully turned off, magnetic energy stored in a boost choke to a bulk capacitor, and to fully turn on, by the control circuit of the PSU, the series transistor again immediately after the series transistor was in a fully turned off state, wherein the fully turning on occurs after the magnetic energy stored in the boost choke has been transferred to the bulk capacitor.

An active inrush current limiter and method of limiting inrush current actively monitor line voltage and voltage drop across a current limiting resistance in a manner that eliminates the impact of fluctuations of line voltage on the decision of when to close a relay and bypass a current limiting resistance between the AC source and a group of power supplies. The active inrush current limiter includes a microcontroller connected to control the electronic switch and relay. The microcontroller is configured to sample the source AC power and detect a pattern of current flow through the electronic switch and current limiting resistance. A program executed in the microcontroller includes calculations that determine when to close the relay and bypass the current limiting resistance by detecting changes in power flow through the current limiting resistance that reliably correspond to a time when the capacitors in the power supplies have completed charging.

There is described systems and methods for managing an electrical surge of railway signaling equipment. A breaker includes a mechanical reset button that shifts positions in response to detecting the electrical surge exceeding a threshold amperage. An opto-isolator deenergizes in response to the position shift of the mechanical reset button. The event recorder transmits an alarm signal to a remote office system in response to the deenergizing of the opto-isolator.

An electronic blood pressure meter includes a cuff that is to be worn on a measurement area, a piezoelectric pump that adjusts a pressure applied to the cuff, a drive circuit that drives the piezoelectric pump, and a controller that outputs, to the drive circuit, a pulse signal defining a driving timing of the piezoelectric pump. The drive circuit includes a switching circuit for switching a connection relationship between respective voltages applied to both ends of the piezoelectric pump in response to corresponding first and second driving signals, and a signal generation circuit that outputs the first and second driving signals based on the pulse signal outputted from the controller. The signal generation circuit has a signal conditioning circuit that adjusts timings of the first and second driving signals so that the phases of the first and second driving signals do not overlap.

A method for suppressing magnetizing inrush current of the transformer with flux linkage control includes connecting a small-capacity direct current/alternating current (DC/AC) converter with the secondary winding or auxiliary winding of transformer, detecting the primary side phase voltage before closing load, inducing the core flux linkage reference according to the relationship between the winding voltage and core flux linkage. The core flux linkage closed-loop PI control system is constructed to control the converter voltage in the synchronous coordinate, then the core flux linkage can track its reference with no static error, thus the sinusoidal flux linkage with 90-degree difference from the grid voltage can be pre-established in the core before no-load closing. By these methods, no matter when the main transformer closes, the core flux linkage is always in the steady state, and the magnetizing inrush current can be eliminated completely.

The present invention is concerned with pre-magnetizing a Modular Multilevel power Converters connected transformer in order to moderate inrush currents upon connecting the transformer to an electric grid. The invention takes advantage of the high amount of stored energy in MMC converters as compared to other converter types. This stored energy is used to pre-magnetize the converter-connected transformer, therefore no additional or dedicated pre-magnetizing hardware is required in addition to the charging hardware provided to charge the converter capacitors. As the transformer pre-magnetizing takes place subsequent to the converter charging, the converter charging circuit is not used to, and therefore does not need to be designed to, directly magnetize the transformer.

Provided is a solid state power controller (SSPC). The SSPC comprises a power supply line configured to be connected between a power source and a load. Further, the solid state power controller comprises a semiconductor switching unit provided on the power supply line and configured to switch between at least two states according to a command signal. The at least two states include a conducting state and a non-conducting state. Further the solid state power controller comprises a state machine, which is configured to exhibit at least two states, including an ON state and an OFF state. The state machine is further configured to output the command signal according to a current state of the state machine.

An FET makes an upstream power supply circuit an energized state and makes the upstream power supply circuit an interrupted state. An FET makes a downstream power supply circuit an energized state and makes the downstream power supply circuit an interrupted state. An FET turns on to make an anode and a cathode of the capacitor an energized state, and turns off to make the anode and the cathode an interrupted state. A controller turns on the FET and the FET and turns off the FET to make a power supply circuit an energized state. When a certain discharge request is input in the energized state of the power supply circuit, the controller turns off the FET and turns on the FET and the FET. With this configuration, a semiconductor relay device can appropriately address the power supply circuit at the time of abnormality.