Power-packet-switching circuits (and methods and systems) in which at least one port uses series-connected combinations of bidirectional switches to connect a link inductor (or transformer), with selectable polarity, to an outside line. Optionally, series-connected combinations of bidirectional switches are used for phase legs in some ports, while single bidirectional switches are used for the phase legs in other ports. This can be particularly advantageous where the converter interfaces between lines at significantly different operating voltages. By using B-TRANs as the series-combined elements of the combinations of switches, voltage-dividing circuitry is not needed to equalize the voltages seen by the individual devices in each combination.

An electrical system can include a first bidirectional AC-DC converter having an input couplable to a grid connection and an output couplable to a battery and a second bidirectional AC-DC converter having an input couplable to the grid connection or a convenience outlet and an output couplable to the battery. The electrical system can further include a controller that controls the first and second converters to operate in a plurality of modes including a two-stage charging mode in which the first and second converters operate in a forward direction to charge the battery, a single-stage charging mode in which the first converter operates in a forward direction to charge the battery and the second converter operates in a reverse direction to power the convenience outlet, and a non-charging mode in which the first converter is idle and the second converter operates in a reverse direction to power the convenience outlet.

A direct current (DC) power secondary distribution system is provided. The system comprises at least one first conversion unit and a one or more second conversion units. The first conversion unit receives alternating current (AC) electrical voltage from a distribution transformer of an AC power distribution system and converts the AC electrical voltage to DC electrical voltage output. The one or more second conversion units are connected downstream of the first conversion unit, and each second conversion unit converts the DC electrical voltage output from the first conversion unit to a respective AC electrical voltage output for a respective one or more loads. The one or more loads may be associated with a household.

An AC-DC converter 1 has, e.g.: a primary winding 11 to which an alternating-current input voltage Vi is applied; a secondary winding 12 magnetically coupled with the primary winding 11; a bidirectional switch 20 connected in series with the primary winding 11; a resonance capacitor 30 connected in parallel with at least one of the bidirectional switch 20 and the primary winding 11; a resonance inductance component (e.g., a coil 120); a full-wave rectification circuit 40 performing full-wave rectification on an induced voltage appearing in the secondary winding 12; and a smoothing capacitor 50 smoothing the output of the full-wave rectification circuit 40. The alternating-current input voltage Vi is converted directly into a direct-current output voltage Vo, with both a forward voltage and a flyback voltage extracted from the secondary winding 12. The converter 1 further has a switch 200 switching the number of turns of the primary winding.

A modular multilevel converter and a power electronic transformer is provided. The modular multilevel converter includes: a low-frequency AC to DC conversion module, comprising three branch circuits connected in parallel between output ends, each branch circuit being formed of multiple IGBT half-bridge circuits connected in series, and an electric coupling point of two adjacent IGBT half-bridge circuits in a middle position of the branch circuit being connected to a voltage input end Vin; a DC to high-frequency AC conversion module, connected between the output ends, the DC to high-frequency AC conversion module being formed of multiple IGBT half-bridge circuits connected in series, the DC to high-frequency AC conversion module having multiple sets of output ends. The MMC and power electronic transformer includes a smaller volume, lower cost and better stability in use.

A power distribution system in which a power source is configured to supply an amount of high-frequency input power to a centralized frequency converter unit. The centralized frequency converter unit is configured to convert the high-frequency input power into low-frequency converted power. Passenger Electronic Device Controllers receive the converted power and distribute it to outlet units. Power management functions may be integrated with the distribution system. For instance, the centralized frequency converter unit can cause to be disabled unused outlet units when the power drawn by the used outlet units exceeds a predetermined threshold.

An apparatus for high-speed switching between a plurality of power sources includes a switch-mode isolation transformer. The switch-mode isolation transformer includes a plurality of isolated primary windings. Each of the plurality of isolated primary windings can be electrically isolated from others of the isolated primary windings and selectively couplable to a power source of the plurality of power sources. The switch-mode isolation transformer further includes a secondary winding coupled to a load. The apparatus further includes a controller to selectively couple one of the plurality of power sources through a corresponding isolated primary winding, responsive to detecting an adverse condition in another power source of the plurality of power sources. Other methods and systems are also described.

The present invention discloses a distributed high-frequency AC electrical system for the electric vehicle. The system divides all loads of the electric vehicle into four load areas according to their spatial positions. Four high-frequency inverters and four DC input interfaces are contained in the system, with each of the four load areas being configured with one of the four high-frequency inverters, and each of the four high-frequency inverters being configured with one of the four DC input interfaces. One end of each DC input interface is connected to the DC side of the corresponding high-frequency inverter, and the other end is connected to the storage battery of the electric vehicle. Each high-frequency inverter outputs a high-frequency AC bus to supply power for the loads in the corresponding load area, and the four high-frequency inverters are in a parallel operation state through a high-frequency connection point that connects the four high-frequency AC buses. The present invention has the advantages of simplifying the electrical system structure of the electric vehicle, improving the system stability, and the like.

In one embodiment, a power cell module includes: a high frequency line converter (HFLC) to receive a phase of input power from a utility source, the HFLC including a first silicon carbide (SiC) stage and a second SiC stage; a transformer having a primary coil coupled to the HFLC and a secondary coil coupled to a high frequency motor converter (HFMC); the HFMC to output a phase of output power to a load, the HFMC including a third SiC stage and a fourth SiC stage; and a two-phase cooling system having conduits that are adapted to provide a flow of cooling media through the HFLC, the transformer and the HFMC.

Unique systems, methods, techniques and apparatuses of a modular power transformer are disclosed. One exemplary embodiment is a matrix power transformer including a plurality of block assemblies each including a plurality of transformer modules, each transformer module including a primary winding coupled to an input and a secondary winding coupled to an output, the inputs of each transformer module in one block assembly being coupled together and the outputs of each transformer block being coupled together. One of the secondary windings includes a plurality of taps structured to be selectively coupled to the output of the associated transformer module assembly or another secondary winding of the associated module assembly.