The present disclosure relates to a phase shifting transformer. The phase shifting transformer includes two exciting windings sharing the same three double taped coils, a first excited winding having three connected coils, for a phase shift regulation, a second excited winding comprising three connected coils, for a voltage regulation, each of the two exciting windings regulating the voltage of one coil of the second excited winding, and regulating the voltage level of one coil of the first excited winding.

A DC power distribution system includes: a transformer; a rectification device; a DC bus through which DC power flows; a plurality of DC branch lines branching off from the DC bus; an AC interrupting portion connected to an input side of the transformer; a first DC interrupting portion connected between the rectification device and the DC bus; and a plurality of second DC interrupting portions respectively provided to the plurality of DC branch lines. An interrupting-operation time for each second DC interrupting portion is set to be shorter than interrupting-operation times for the AC interrupting portion and the first DC interrupting portion. An inductance value of a short-circuit impedance of the transformer is set to a value at which short-circuit current can be limited to take a value not larger than a maximum current value permitted for the rectification device.

A DC power distribution system includes: a transformer; a rectification device; a DC bus through which DC power flows; a plurality of DC branch lines branching off from the DC bus; an AC interrupting portion connected to an input side of the transformer; a first DC interrupting portion connected between the rectification device and the DC bus; and a plurality of second DC interrupting portions respectively provided to the plurality of DC branch lines. An interrupting-operation time for each second DC interrupting portion is set to be shorter than interrupting-operation times for the AC interrupting portion and the first DC interrupting portion. An inductance value of a short-circuit impedance of the transformer is set to a value at which short-circuit current can be limited to take a value not larger than a maximum current value permitted for the rectification device.

The embodiments herein relate to a system (100) for controlling a 3-phase transformer device (101, T1, T2, T3). The system (100) comprises the 3-phase transformer device (101, T1, T2, T3) which comprises a primary side and an adjustable secondary side. The system (100) comprises at least one voltage sensor (S1, S2, S3) adapted to sense voltage at the primary side. The system (100) comprises a current sensor (S4) adapted to sense current through the adjustable secondary side, and a resistor (R1) connected in series with the current sensor (S4) at the adjustable secondary side. The system comprises a controller (103) adapted to obtain sensor data indicating the sensed voltage and the sensed current, and to control a parameter associated with the adjustable secondary side of the 3-phase transformer device (101, T1, T2, T3) based on the obtained sensor data.

A power conversion system includes: a self-excited power converter to perform power conversion between a first AC system and a DC system; a first transformer having a primary side connected to the first AC system and a secondary side connected to the self-excited power converter; and a first impedance circuit connected between a ground and a neutral point on the secondary side of the first transformer, or between the ground and an AC line connecting the secondary side of the first transformer and the self-excited power converter. The first impedance circuit includes one of a reactor and another transformer.

An uninterruptible power supply system includes: at least one AC input terminal; an AC output terminal; an DC input terminal; at least one uninterruptible power supply (UPS) device having: a DC link; a DC/AC converter connecting on a first side to the DC link and on a second side to the AC output terminal; and a DC/DC converter connecting on a first side to the DC input terminal and on second side to the DC link. The uninterruptible power supply system further includes at least two switches; and at least one coupled differential mode inductor having two windings. Each switch of the at least two switches is connected in series with at least one winding of the at least one coupled differential mode inductor forming a series connection. The series connection is connected on a first side to the at least one AC input terminal.

A DC power distribution system includes: a transformer; a rectification device; a DC bus through which DC power flows; a plurality of DC branch lines branching off from the DC bus; an AC interrupting portion connected to an input side of the transformer; a first DC interrupting portion connected between the rectification device and the DC bus; and a plurality of second DC interrupting portions respectively provided to the plurality of DC branch lines. An interrupting-operation time for each second DC interrupting portion is set to be shorter than interrupting-operation times for the AC interrupting portion and the first DC interrupting portion. An inductance value of a short-circuit impedance of the transformer is set to a value at which short-circuit current can be limited to take a value not larger than a maximum current value permitted for the rectification device.

A DC power distribution system includes: a transformer; a rectification device; a DC bus through which DC power flows; a plurality of DC branch lines branching off from the DC bus; an AC interrupting portion connected to an input side of the transformer; a first DC interrupting portion connected between the rectification device and the DC bus; and a plurality of second DC interrupting portions respectively provided to the plurality of DC branch lines. An interrupting-operation time for each second DC interrupting portion is set to be shorter than interrupting-operation times for the AC interrupting portion and the first DC interrupting portion. An inductance value of a short-circuit impedance of the transformer is set to a value at which short-circuit current can be limited to take a value not larger than a maximum current value permitted for the rectification device.

A stacked half bridge converter may be configured to provide an AC output voltage from either a DC or an AC input voltage. The switching devices of the converter may be operated according to a plurality of switching sequences, each switching sequence including one or more switching patterns, each switching pattern including one or more switching states of the switching devices. The switching sequences, patterns, and states may be selected to improve operation of the converter, by regulating the voltage at a neutral point of the converter to reduce ripple, increase switching efficiency, protect the switching devices from overvoltages, and the like.

Systems and methods for an alternating current (AC) input selection for a power transformer are disclosed. In particular, a connector is provided that is pre-wired to utilize internal wiring in the power transformer to provide a desired connection. A first option allows two transformers' input winding to be in series while a second option allows the two transformers' input winding to be in parallel. By moving the wiring into the connector, installation is simplified as the wiring has already been done. The installer need only attach the correct plug based on the desired voltage and couple the plug to the transformer. Further, the manipulation of thick wires is also avoided by the installer, further simplifying the installation process.