Techniques for converting power received from a power grid at a first voltage and outputting a signal at a second voltage are discussed herein. A power converter with a transformer that has a 22.5 degrees phase shift between current output by corresponding pairs of secondary windings can be utilized to convert power of a first level to power of a second level. The transformer can output power from 30 secondary windings. The power converter can output power with a total harmonic distortion of 5% and an efficiency of 96% or higher. Further, power can be output by a transmission coil and received by a receive coil in a device, such as a vehicle, to wirelessly charge the vehicle.

A ground power unit provides electrical energy for aircraft and a method maintains and operates the ground power unit. The ground power unit includes a base frame, a cable system formed in the base frame, at least one rectifier module for converting an input alternating voltage applied to a rectifier module input side into an intermediate direct voltage output at a rectifier module output side, wherein the rectifier module output side is coupled to an intermediate circuit conductor and at least one inverter module for converting the intermediate direct voltage applied to an inverter module input side into an output alternating current output at an inverter module output side, wherein the inverter module input side is coupled to an intermediate circuit conductor. The rectifier module and the inverter module are each realized as structurally-independent units, which can be replaced individually and independently of the base frame.

A system comprises a first 3-phase rectifier having a positive DC lead and a negative DC lead and a second 3-phase rectifier having a positive DC lead and a negative DC lead. The system also includes a 4-phase, 3-level inverter connected to the first and second 3-phase rectifiers. A method comprises receiving variable frequency, 3-phase power from a first generator, receiving variable frequency, 3-phase power from a second generator, rectifying the variable frequency, 3-phase power from each of the first and second generators into DC power. And inverting the DC power into 4-phase, constant frequency power for powering a load.

A zero-sequence blocking transformer includes a first core part, a first pair of windings wound around the first core part, a second core part and a second pair of windings wound around the second core part, the first core and the second core having a geometry to generate a leakage inductance.

A zero-sequence blocking transformer includes a first core part, a first pair of windings wound around the first core part, a second core part and a second pair of windings wound around the second core part, the first core and the second core having a geometry to generate a leakage inductance.

A power supply system includes a plurality of power conversion devices connected in parallel with each other, a load state detector to detect an operating state of a load connected to the DC system, and a command generator to generate a distribution voltage command Vref Each of the power conversion devices includes a DC voltage controller to generate an output power command Pdc_ref based on a voltage of the DC system and the distribution voltage command Vref, and an AC/DC converter to convert AC power received from the main power source based on the output power command Pdc_ref and output the converted power to the DC system. The command generator generates the distribution voltage command Vref such that loss of the load connected to the DC system is reduced, based on a detection result of the load state detector.

A power supply system includes a plurality of power conversion devices connected in parallel with each other, a load state detector to detect an operating state of a load connected to the DC system, and a command generator to generate a distribution voltage command Vref Each of the power conversion devices includes a DC voltage controller to generate an output power command Pdc_ref based on a voltage of the DC system and the distribution voltage command Vref, and an AC/DC converter to convert AC power received from the main power source based on the output power command Pdc_ref and output the converted power to the DC system. The command generator generates the distribution voltage command Vref such that loss of the load connected to the DC system is reduced, based on a detection result of the load state detector.

An electrical conversion system includes: an inductor electrically connected to an alternating current (AC) power grid; a medium voltage direct current (MVDC) bus; a non-isolated AC/DC converter, provided with a first terminal electrically connected to the inductor and a second terminal electrically connected to the MVDC bus, wherein the non-isolated AC/DC converter is configured to output a bus voltage based on an input voltage from the AC power grid; a plurality of circuit branches connected in parallel, wherein each circuit branch is connected to the MVDC bus via a corresponding converter; and a filtering network disposed between the AC power grid and the MVDC bus and is grounded through at least one capacitor.

An electrical conversion system includes: an inductor electrically connected to an alternating current (AC) power grid; a medium voltage direct current (MVDC) bus; a non-isolated AC/DC converter, provided with a first terminal electrically connected to the inductor and a second terminal electrically connected to the MVDC bus, wherein the non-isolated AC/DC converter is configured to output a bus voltage based on an input voltage from the AC power grid; a plurality of circuit branches connected in parallel, wherein each circuit branch is connected to the MVDC bus via a corresponding converter; and a filtering network disposed between the AC power grid and the MVDC bus and is grounded through at least one capacitor.

Disclosed herein is a charger for charging electric vehicles. In one embodiment, the charger includes M AC/DC converters, a DC bus, N DC/DC converters, and D energy exchange ports. The M AC/DC converters are configured to be coupled to a power source at an input side of the M AC/DC converters. The DC bus is connected to an output side of each of the M AC/DC converters. The N DC/DC converters are coupled to the DC bus at an input side of the N DC/DC converters. The D energy exchange ports are coupled to an output side of one or more of the N DC/DC converters at an input side of the D energy exchange ports, and each of the D energy exchange ports is configured to be coupled to an electric vehicle, where N>M, and where an energy storage is coupled to the DC bus.