An ideal diode circuit is described which uses an NMOS transistor as a low-loss ideal diode. The control circuit for the transistor is referenced to the anode voltage and not to ground, so the control circuitry may be low voltage circuitry, even if the input voltage is very high, referenced to earth ground. A capacitor is clamped to about 10-20V, referenced to the anode voltage. The clamped voltage powers a differential amplifier for the detecting if the anode voltage is greater than the cathode voltage. The capacitor is charged to the clamped voltage during normal operation of the ideal diode by controlling the conductivity of a second transistor coupled between the cathode and the capacitor, enabling the circuit to be used with a wide range of frequencies and voltages. All voltages applied to the differential amplifier are equal to or less than the clamped voltage.

An ideal diode circuit is described which uses an NMOS transistor as a low-loss ideal diode. The control circuit for the transistor is referenced to the anode voltage and not to ground, so the control circuitry may be low voltage circuitry, even if the input voltage is very high, referenced to earth ground. A capacitor is clamped to about 10-20V, referenced to the anode voltage. The clamped voltage powers a differential amplifier for the detecting if the anode voltage is greater than the cathode voltage. The capacitor is charged to the clamped voltage during normal operation of the ideal diode by controlling the conductivity of a second transistor coupled between the cathode and the capacitor, enabling the circuit to be used with a wide range of frequencies and voltages. All voltages applied to the differential amplifier are equal to or less than the clamped voltage.

A power conversion device includes a transformer, a plurality of converter cells, and a control circuit that controls semiconductor switching elements in each of the converter cells to be turned on and off. The transformer includes: a primary winding group being connected in multiple phases to an AC power supply including multiple phases; and a plurality of secondary winding groups. Each secondary winding group includes, in each of the multiple phases, secondary windings each formed of a single-phase open winding. Each converter cell converts a single-phase AC voltage between AC nodes connected to the respective secondary windings into a DC voltage by control of the semiconductor switching elements to be turned on and off, and outputs the converted DC voltage between a pair of DC nodes. The DC nodes of the plurality of converter cells are connected in series between a first DC terminal and a second DC terminal.

A power conversion device includes a transformer, a plurality of converter cells, and a control circuit that controls semiconductor switching elements in each of the converter cells to be turned on and off. The transformer includes: a primary winding group being connected in multiple phases to an AC power supply including multiple phases; and a plurality of secondary winding groups. Each secondary winding group includes, in each of the multiple phases, secondary windings each formed of a single-phase open winding. Each converter cell converts a single-phase AC voltage between AC nodes connected to the respective secondary windings into a DC voltage by control of the semiconductor switching elements to be turned on and off, and outputs the converted DC voltage between a pair of DC nodes. The DC nodes of the plurality of converter cells are connected in series between a first DC terminal and a second DC terminal.

A wind power converting device includes a plurality of grid-side converters, a plurality of generator-side converters and a plurality of DC buses. The grid-side converters are connected with each other in series and electrically coupled to a power grid. The generator-side converters are connected with each other in series and electrically coupled to a generator device. The DC buses are electrically coupled between the grid-side converters and the generator-side converters. The DC buses include a positive DC bus, a negative DC bus and at least one intermediate DC bus between the positive DC bus and the negative DC bus. A cross section area of a conductor of the intermediate DC bus is smaller than 30% of a cross section area of a conductor of the positive DC bus or smaller than 30% of a cross section area of a conductor of the negative DC bus.

The invention provides a power distribution and drive system for a remotely underwater operated vehicle ROV, comprises: a high-voltage DC power supply device, located above the water surface to provide high-voltage DC voltage to the ROV; a DC buck conversion device, connected to the high-voltage DC power supply device through a cable for converting the high-voltage DC voltage to a low-voltage DC voltage to supply power to the ROV, wherein the DC buck conversion device comprises multiple parallel DC conversion modules, each DC conversion module bearing an average load current to supply power to the ROV; and at least one thruster, which comprises a propeller, a synchronous motor, and a driver.

The invention provides a power distribution and drive system for a remotely underwater operated vehicle ROV, comprises: a high-voltage DC power supply device, located above the water surface to provide high-voltage DC voltage to the ROV; a DC buck conversion device, connected to the high-voltage DC power supply device through a cable for converting the high-voltage DC voltage to a low-voltage DC voltage to supply power to the ROV, wherein the DC buck conversion device comprises multiple parallel DC conversion modules, each DC conversion module bearing an average load current to supply power to the ROV; and at least one thruster, which comprises a propeller, a synchronous motor, and a driver.

An electrical converter (203) having an active diode-clamped multilevel topology is shown. Each clamping diode is connected in antiparallel with a switch (S5A, S5B). The converter comprises polyphase supply phases (A, B, C) each of which are connected via a respective phase leg (401, 402, 403) to dc rails (301, 302) and a dc-link capacitor. The dc-link capacitor includes a plurality of series-connected capacitors (404, 405). A controller is configured to, in response to an event signal, for each phase leg, activate a combination of switches therein to form a pair of parallel conduction paths to a midpoint (406) between two capacitors in the dc-link capacitor, thereby connecting each phase to the same node.

An electrical converter (203) having an active diode-clamped multilevel topology is shown. Each clamping diode is connected in antiparallel with a switch (S5A, S5B). The converter comprises polyphase supply phases (A, B, C) each of which are connected via a respective phase leg (401, 402, 403) to dc rails (301, 302) and a dc-link capacitor. The dc-link capacitor includes a plurality of series-connected capacitors (404, 405). A controller is configured to, in response to an event signal, for each phase leg, activate a combination of switches therein to form a pair of parallel conduction paths to a midpoint (406) between two capacitors in the dc-link capacitor, thereby connecting each phase to the same node.

An AC/DC power converter includes an input port configured to receive an AC power signal, a first transformer coupled to the input port, the first transformer comprising first and second primary windings and at least a first secondary winding, and a second transformer coupled to the input port, the second transformer comprising third and fourth primary windings and at least a second secondary winding. The first primary winding of the first transformer is coupled in series with the third primary winding of the second transformer, the second primary winding of the first transformer is coupled in series with the fourth primary winding of the second transformer, and the first secondary winding and the second secondary winding are coupled in parallel.