Embodiments of this application provide a power conversion circuit. The power conversion circuit includes at least one first power conversion unit connected in series to a first phase line, at least one second power conversion unit connected in series to a second phase line, at least one third power conversion unit connected in series to a third phase line, a plurality of first start circuits connected in series to the first phase line, and a plurality of second start circuits connected in series to the second phase line. Each first start circuit includes a first relay and a first resistor that are connected in parallel, and first relays in all the first start circuits are sequentially closed after the power conversion circuit is powered on, to start the power conversion circuit. Each second start circuit includes a second relay and a second resistor that are connected in parallel.

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.

A trans-inductor voltage regulator with fault detection has a plurality of transformers. Each transformer of the plurality of the transformers has a primary winding coupled to a switching circuit, and a secondary winding. Each secondary winding of each transformer of the plurality of transformers are coupled in series with a compensation inductor. The trans-inductor further has a controller operable to detect a) a short condition in a secondary side of each transformer of the plurality of transformers, b) a short condition between a primary side and the secondary side of each transformer of the plurality of transformers; c) an open condition in the primary side of each transformer of the plurality of transformers; and d) an open condition in the secondary side of each transformer of the plurality of transformers.

A trans-inductor voltage regulator with fault detection has a plurality of transformers. Each transformer of the plurality of the transformers has a primary winding coupled to a switching circuit, and a secondary winding. Each secondary winding of each transformer of the plurality of transformers are coupled in series with a compensation inductor. The trans-inductor further has a controller operable to detect a) a short condition in a secondary side of each transformer of the plurality of transformers, b) a short condition between a primary side and the secondary side of each transformer of the plurality of transformers; c) an open condition in the primary side of each transformer of the plurality of transformers; and d) an open condition in the secondary side of each transformer of the plurality of transformers.

An isolation transformer boost system. The system including a power supply and an isolation transformer. The isolation transformer including a primary winding electrically connected to the power supply, a secondary winding, a first voltage tap, and a second voltage tap. The isolation transformer is configured to, in response to a command from an electronic processor, disconnect a connection from the first voltage tap and establish a second connection from the second voltage tap.

A reverse power feeding (RPF) power supply unit (PSU) for remote network distribution point unit (DPU) that is reverse powered from multiple customer premise equipments (CPEs). A plurality of power converters, each having a different primary winding and sharing a common secondary winding of a transformer at the PSU, wherein only one of the power converters is operated at a time to provide a desired output voltage.

A reverse power feeding (RPF) power supply unit (PSU) for remote network distribution point unit (DPU) that is reverse powered from multiple customer premise equipments (CPEs). A plurality of power converters, each having a different primary winding and sharing a common secondary winding of a transformer at the PSU, wherein only one of the power converters is operated at a time to provide a desired output voltage.

This application provides an isolation transformer. The isolation transformer is applicable to a power converter, the power converter further includes a first power conversion module and a second power conversion module, the isolation transformer includes a high-voltage winding, a low-voltage winding, and a solid insulation housing. The high-voltage winding has a solid insulation layer and the solid insulation housing has an opening surface, the opening surface faces the second power conversion module, the solid insulation housing covers the low-voltage winding and the high-voltage winding that has the solid insulation layer, a conducting layer or a semi-conducting layer is disposed on the solid insulation housing, and the conducting layer or the semi-conducting layer of the solid insulation housing is grounded. In this application, a volume of the isolation transformer can be reduced, power density of the power converter can be improved, and low costs and high applicability can be ensured.

This application provides an isolation transformer. The isolation transformer is applicable to a power converter, the power converter further includes a first power conversion module and a second power conversion module, the isolation transformer includes a high-voltage winding, a low-voltage winding, and a solid insulation housing. The high-voltage winding has a solid insulation layer and the solid insulation housing has an opening surface, the opening surface faces the second power conversion module, the solid insulation housing covers the low-voltage winding and the high-voltage winding that has the solid insulation layer, a conducting layer or a semi-conducting layer is disposed on the solid insulation housing, and the conducting layer or the semi-conducting layer of the solid insulation housing is grounded. In this application, a volume of the isolation transformer can be reduced, power density of the power converter can be improved, and low costs and high applicability can be ensured.

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.