Aspects of an efficient, wide voltage range, power converter system are described. In one example, a power converter system includes a first power converter, a second power converter, and a controller for the power converter. An input of the first power converter and an input of the second power converter are connected in series across an input voltage for the power converter system, and an output of the first power converter and an output of the second power converter are connected in parallel at an output of the power converter system. The controller is configured to regulate the second power converter and to determine whether or not to regulate the first power converter based on the input voltage for the power converter system and an output voltage of the power converter system, among other factors, for greater efficiency of the power converter system over wider input and output voltage ranges.

An electrical supply system, suitable for supplying a plurality of separate loads from one AC source, including at least two single-phase or multi-phase electrical transformers, each including one primary induction circuit and one secondary induction circuit. The primary induction circuits are connected in series forming a succession of transformers. For each of the transformers, the secondary induction circuit includes at least two groups of secondary windings, each group of secondary windings having at least one group of output terminals. One of the groups of output terminals is connected to at least one of the loads to be supplied, and another of the groups of output terminals is connected to one of the groups of output terminals of another transformer in the succession of transformers, so as to achieve a parallel connection of the secondary induction circuits.

This application discloses a power electronic transformer wherein each phase includes a plurality of power conversion modules. Each power conversion module includes a rectifier AC/DC circuit, a direct current bus capacitor, and a direct current-direct current DC/DC circuit. In each power conversion module, an output end of the AC/DC circuit is connected to an input end of the DC/DC circuit; the direct current bus capacitor is connected in parallel to the output end of the AC/DC circuit; and input ends of all the AC/DC circuits are connected in series, and output ends of all the DC/DC circuits are connected in parallel. The power electronic transformer includes a relatively small quantity of power conversion modules, thereby reducing occupied space and costs.

A motor driving system includes first and second motors including multiple first windings and second windings; a first inverter including a DC terminal connected to a DC voltage source and an AC terminal connected to the multiple first windings; a first switch part including a plurality of first mode change switches connected to the multiple first windings; a second inverter including a DC terminal connected to the DC voltage source and an AC terminal connected to the plurality of first mode change switches; a second switch part including a plurality of second mode change switches connected to the AC terminal of the second inverter and the multiple second windings; a third switch part including a plurality of third mode change switches connected to the multiple first windings; and a controller configured to control the short-circuited state or the open state of the multiple first mode, second and third mode change switches, based on whether the first and the second motors are driven.

Disclosed herein is a modular, scalable, and galvanically isolated power electronics converter topology for medium voltage AC (MVAC) to DC or high voltage AC (HVAC) to DC power conversion. A disclosed modular converter can comprise a low-voltage direct current bus and a centralized controller configured to regulate the low-voltage direct current bus. The modular converter can further comprise a plurality of three-phase blocks connected in series. Individual three-phase blocks of the plurality of three-phase blocks can comprise a plurality of single-phase modules connected in an input-series output-parallel configuration. The modular converter can further comprise a filter connected between a grid input and the plurality of three-phase blocks and a pulse-width modulator configured to generate encoded gate pulses for the individual three-phase blocks of the plurality of three-phase blocks.

The present disclosure provides a DC conversion system and a control method thereof. The DC conversion system comprises: an upper power module group, a lower power module group, input terminals of the upper and lower power module group are connected in series, and output terminals of the upper and lower power module groups are connected in parallel; the controller configured to receive an input voltage of respective input terminal of each of the first and second power modules, a first output current of the output terminal of the upper power module group, a second output current of the output terminal of the lower power module group, and a total output signal of the output terminal of the DC conversion system, and generate a modulation signal according to them to control a power switch of the corresponding power module.

Accordingly, the embodiments herein provide a hybrid modular multilevel converter. The hybrid modular multilevel converter includes one or more chain links, one or more high voltage switches and a plurality of inductors. The one or more chain links are formed by sub modules. The one or more high voltage switches are formed by semi-controlled devices or fully controlled or any other suitable semiconductor devices. The plurality of inductors are arranged in the one or more chain links to limit circulating current among the one or more chain links. The one or more chain links are configured to enhance a power handling capability of the hybrid modular multilevel converter.

In a start-up control in which primary-side direct-current (DC) terminals and secondary-side DC terminals are charged by an external power supply outside a power conversion device, initially, one-side DC terminals are charged by the external power supply while switching operations of the primary-side bridge circuit and the secondary-side bridge circuit are stopped. Subsequently, a bridge circuit that is connected to the DC terminals not charged by the external power supply stops the switching operation and operates in a diode rectifying mode, while a bridge circuit that is connected to the DC terminals charged by the external power supply performs the switching operation and outputs an AC voltage whose voltage pulse width has been subjected to a variable control so that the voltage pulse width is smaller for a greater voltage difference of the charged DC terminals from the uncharged DC terminals.

Aspects of direct current (DC)-DC converters with an integrated matrix transformer and multiphase current doubler rectifiers are described. In some examples, a DC-DC converter can include a matrix transformer that has multiple magnetically integrated transformer components that are magnetically integrated using transformer components that share a top plate and a bottom plate. A multiphase current doubler rectifier can include multiple synchronous rectifiers corresponding to the plurality of transformer components of the matrix transformer.

A power apparatus applied in a solid state transformer structure includes an AC-to-DC conversion unit, a first DC bus, and a plurality of bi-directional DC conversion units. First sides of the bi-directional DC conversion units are coupled to the first DC bus. Second sides of the bi-directional DC conversion units are configured to form at least one second DC bus, and the number of the at least one second DC bus is a bus number. The bi-directional DC conversion units receive a bus voltage of the first DC bus and convert the bus voltage into at least one DC voltage, or the bi-directional DC conversion units receive at least one external DC voltage and convert the at least one external DC voltage into the bus voltage.