Abstract: A DC supply and distribution system includes an AC-DC converter for converting an AC power input from an AC power line to DC powers having a plurality of different voltages and outputting the converted DC powers; and a voltage controller for controlling the different voltages of the DC powers to be output from the AC-DC converter. The output DC powers are distributed to the plurality of loads through a plurality of respective DC lines connected from the output terminals of the AC-DC converter.

Abstract: A power conversion device includes a first bridge circuit, a second bridge circuit, and an inductance element connected between a first AC terminal of the first bridge circuit and a second AC terminal of the second bridge circuit. The controller calculates a passing current passing through the inductance element based on a difference between a first alternating current flowing between the first AC terminal and the inductance element and a second alternating current flowing between the second AC terminal and the inductance element, and detects a first DC component included in the passing current. The controller changes a duty in at least one of the first AC voltage and the second AC voltage to cancel the detected first DC component, the duty being a ratio of a positive potential period and a negative potential period.

Abstract: A multiwinding transformer includes a primary-side winding and a plurality of secondary-side windings. A primary-side bridge circuit to carry out DC/AC power conversion is connected between a primary-side DC terminal connected to a DC power supply and the primary-side winding. A plurality of secondary-side bridge circuits to carry out DC/AC power conversion are connected between the plurality of secondary-side windings and a plurality of secondary-side DC terminals, respectively. The plurality of secondary-side windings include a first secondary-side winding strongest in magnetic coupling to the primary-side winding and a second secondary-side winding weaker in magnetic coupling to the primary-side winding than the first secondary-side winding.

Abstract: A transformer includes a first core, a first primary coil, a first secondary coil, and a first insulating member. The first secondary coil includes a second conductor wound around the first core. The first insulating member covers the first secondary coil. The second conductor has a shape of a first polygon in a cross-section of the second conductor. A first corner of the first polygon has a first radius of curvature of 0.1 mm or more. The transformer thus has improved dielectric breakdown voltage and improved power efficiency.

Abstract: A transformer includes a first iron core group, a second iron core group, and winding portions. The first iron core group includes iron core stacks. The second iron core group includes iron core stacks each disposed to face a corresponding one of the iron core stacks of the first iron core group. Each of the winding portions is wound around its corresponding iron core stack of the first iron core group and its corresponding iron core stack of the second iron core group, the corresponding one iron core stack of the second iron core group facing the corresponding one iron core stack of the first iron core group. The iron core stacks of the first iron core group and the iron core stacks of the second iron core group each include annular iron cores stacked alternately.

Abstract: A multiwinding transformer includes a primary-side winding and a plurality of secondary-side windings. A primary-side bridge circuit is connected between a primary-side DC terminal and the primary-side winding. A plurality of secondary-side bridge circuits are connected between the plurality of secondary-side windings and a plurality of secondary-side DC terminals, respectively. A switching converter variably controls a first DC voltage of the primary-side DC terminal or a second DC voltage of a first secondary-side DC terminal among the plurality of secondary-side DC terminals such that a voltage ratio between the first DC voltage and the second DC voltage is controlled to a constant ratio in accordance with a turns ratio between the primary-side winding and the secondary-side winding corresponding to the first secondary-side DC terminal among the plurality of secondary-side windings.

Abstract: The present DC power supply and distribution system includes a plurality of distribution lines provided respectively corresponding to a plurality of loads, a first converter to convert an AC voltage from a commercial AC power source into a plurality of DC voltages and supply the DC voltages respectively to the distribution lines, a second converter to convert a DC power from a power generation and storage source into a plurality of DC powers and supply the DC powers respectively to the distribution lines, and a power controller to control the DC powers such that the efficiency of the first converter is increased, based on information related to the efficiency of the second converter.

Abstract: A DC supply and distribution system includes an AC-DC converter for converting an AC power input from an AC power line to DC powers having a plurality of different voltages and outputting the converted DC powers; and a voltage controller for controlling the different voltages of the DC powers to be output from the AC-DC converter. The output DC powers are distributed to the plurality of loads through a plurality of respective DC lines connected from the output terminals of the AC-DC converter.

Abstract: 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.

Abstract: Provided is a power conversion device capable of continuing the transmission of power even in the event of failure of a DC-to-DC converter cell. The power conversion device according to the present invention includes: a unit having a plurality of DC-to-DC converter cells; a short-circuit device that short-circuits a failed cell; and a control circuit that controls the plurality of DC-to-DC converter cells. The control circuit controls the voltage of a second cell terminal of a healthy cell included in a unit that includes the failed cell, based on a failed cell count m, so that the power of a first cell terminal and the power of the second cell terminal are matched.

Abstract: A power conversion device includes M number of DC/DC converters, first-side terminals of the DC/DC converters are connected so that common current flows between both positive and negative terminals of first DC terminals of the power conversion device, and second-side terminals thereof are connected so that common current flows between both positive and negative terminals of second DC terminals of the power conversion device. The power conversion device further includes M-1 number of auxiliary converters each connected between two DC/DC converters and performing DC/DC conversion. The DC/DC converters control voltages of the second-side terminals and input voltage of the power conversion device. Each auxiliary converter controls voltages of the first-side terminals of the two DC/DC converters so as to be equalized.

Abstract: A submodule includes a bridge circuit including two main power semiconductors connected in series for performing power conversion by on/off control and an electric energy storage element connected in parallel with a path of the two main power semiconductors connected in series, a bypass unit including a bypass power semiconductor), a bypass unit drive device to drive the bypass unit, a first external terminal, and a second external terminal. The first external terminal is connected to a node between the two main power semiconductors. The power conversion apparatus further includes an optical power-feed system for feeding power to the bypass unit drive device.

Abstract: A power conversion device includes a first bridge circuit, a second bridge circuit, and an inductance element connected between a first AC terminal of the first bridge circuit and a second AC terminal of the second bridge circuit The controller calculates a passing current passing through the inductance element based on a difference between a first alternating current flowing between the first AC terminal and the inductance element and a second alternating current flowing between the second AC terminal and the inductance element, and detects a first DC component included in the passing current. The controller changes a duty in at least one of the first AC voltage and the second AC voltage to cancel the detected first DC component, the duty being a ratio of a positive potential period and a negative potential period.

Abstract: A transformer includes a first core, a first primary coil, a first secondary coil, and a first insulating member. The first secondary coil includes a second conductor wound around the first core. The first insulating member covers the first secondary coil. The second conductor has a shape of a first polygon in a cross-section of the second conductor. A first corner of the first polygon has a first radius of curvature of 0.1 mm or more. The transformer thus has improved dielectric breakdown voltage and improved power efficiency.

Abstract: A transformer includes a first iron core group, a second iron core group, and winding portions. The first iron core group includes iron core stacks. The second iron core group includes iron core stacks each disposed to face a corresponding one of the iron core stacks of the first iron core group. Each of the winding portions is wound around its corresponding iron core stack of the first iron core group and its corresponding iron core stack of the second iron core group, the corresponding one iron core stack of the second iron core group facing the corresponding one iron core stack of the first iron core group. The iron core stacks of the first iron core group and the iron core stacks of the second iron core group each include annular iron cores stacked alternately.

Abstract: A power conversion device which is a test target performs DC voltage conversion between a primary side DC terminal and a secondary side DC terminal. A first connection member electrically connects a testing power supply and the primary side DC terminal serving as an input side of the test target. A second connection member electrically connects the primary side DC terminal and the secondary side DC terminal of the power conversion device to transmit active power output from the secondary side DC terminal to the primary side DC terminal to be a part of active power input to the primary side DC terminal.

Abstract: A power converter performs DC power conversion between a pair of first DC terminals and a pair of second DC terminals. DC nodes of n DC/AC converters are connected in parallel or in series between the first DC terminals. A multiple transformer has n primary windings and n secondary windings. An AC node of each DC/AC converter is connected to its corresponding primary winding. An AC node of each AC/DC converter is connected to its corresponding secondary winding. DC nodes of n AC/DC converters are connected in series or in parallel between the second DC terminals. The multiple transformer is configured such that a magnetic path is shared among the n primary windings and a magnetic path is shared among the n secondary windings.

Abstract: A power conversion device includes a plurality of leg circuits and a control device. The plurality of leg circuits correspond to respective phases of an AC circuit and connected in parallel between common first and second DC terminals. Each leg circuit includes a plurality of chopper cells each including an energy storage and cascaded to one another and at least one inductance connected in series to the plurality of chopper cells. The control device controls an operation of only at least one chopper cell included in each leg circuit based on a circulating current which circulates through the leg circuits.

Abstract: Each of a plurality of specified chopper cells which are some of a plurality of chopper cells included in each leg circuit in a power conversion device is configured as a full bridge. A control device controls operations of first and second switching elements of each specified chopper cell based on a circulating current which circulates through each leg circuit. The control device controls operations of third and fourth switching elements of each specified chopper cell based on a voltage of a capacitor of the specified chopper cell.

Abstract: Each DC/DC converter includes a transformer, first and second switching circuits each formed of a plurality of legs having a plurality of semiconductor switching elements, and capacitors. When detecting a malfunction in semiconductor switching elements, a control circuit halts a normal operation mode and controls the first switching circuit by a protection mode for turning OFF all the semiconductor switching elements, and controls the second switching circuit by a bypass mode for bypassing the capacitor by turning ON the semiconductor switching elements in a discharge leg and causing a short circuit between the secondary side terminals, after controlling the second switching circuit by a discharge mode for discharging the capacitor by turning ON the semiconductor switching element in a discharge leg.