Hitachi, Ltd.

Hitachi Industrial Products, Ltd.

Yuuichi Mabuchi

Hiroshi Kamizuma

Daisuke Matsumoto

Yukio Hattori

Akira Mima

Tetsuya Kawashima

Akihiko Kanouda

Takae Shimada

Kimihisa Furukawa

Yasuaki Norimatsu

Takuya Ishigaki

Mizuki Nakahara

Ryouhei Miyagawa

Tomonori Ichikawa

Yuki Kawaguchi

Tadahiko Chida

Mitsuhiro Kadota

Hiroyuki Shoji

Shintaro Tanaka

Akira Yonekawa

A plurality of power conversion units, a current sensor that detects a current at an output terminal of the power conversion unit, and a control unit that measures a frequency component in a predetermined frequency range of a current detected by the current sensor are included, the power conversion unit includes an AC/DC converter that outputs AC power at an input terminal to an output terminal, a smoothing capacitor that is connected in parallel to the output terminal and smooths an output voltage, and a variable resistance switch connected between one end of the smoothing capacitor and one end of the output terminal, the control unit controls a resistance value of the variable resistance switch according to a magnitude of a predetermined frequency component detected by the current sensor, and the output terminals of the plurality of power conversion units are connected in parallel to constitute output terminals.

Power conversion device

This power converter device is appropriately configured. Accordingly, a power converter device comprises, for each phase of a three-phase AC, an AC wiring through which AC terminals of a plurality of power conversion units are series-connected along a second direction. Among the power conversion units, power conversion units that correspond to a first phase are series-connected from a first phase line toward a neutral line in a first direction along the second direction. Among the power conversion units, power conversion units that correspond to a second phase adjacent to the first phase are series-connected from a second phase line toward the neutral line in a second direction opposite to the first direction.

Power converter device

An object of the present invention is to sufficiently reduce a switching loss. A control device causes a positive electrode of a first voltage to appear at a second connection point by switching second and third switching elements to an ON state. Next, the control device causes the positive electrode of the first voltage to appear at a first connection point by switching the second and third switching elements to an OFF state. After that, fifth and eighth switching elements are switched to the OFF state, and sixth and seventh switching elements are switched to the ON state.

Power conversion device, power conversion device control device, and power conversion device control method

The power conversion device includes multiple converter cells. Each converter cell includes a pair of primary-side terminals and a pair of secondary-side terminals. The converter cell transmits power between the pair of primary-side terminals and the pair of secondary-side terminals. The primary-side terminals of the multiple converter cells are connected in series to a primary-side power supply system. The secondary-side terminals of the multiple converter cells are connected in series to a secondary-side power supply system. Among the multiple converter cells, the converter cell in which an absolute value of a ground voltage appearing in the pair of primary-side terminals is the highest is different from the converter cell in which an absolute value of a ground voltage appearing in the pair of secondary-side terminals is the highest.

Power conversion device and power conversion device connection method

A power conversion device that suppresses voltage pulsation of a capacitor of a power converter with respect to a control target whose effective power is to be controlled is provided. The power conversion device includes a plurality of power conversion cells that are connected to each other, and convert a primary-side system voltage into a secondary-side system voltage, a capacitor that is connected to each of the plurality of power conversion cells, and a power conversion cell driver that drives the power conversion cells to add a 3N order higher-harmonic-wave voltage of each of alternating voltages of the plurality of power conversion cells to the each of alternating voltages, and output a voltage made by adding the each of alternating voltages and the 3N order higher-harmonic-wave voltage, when N is a natural number.

In a power conversion device, a power conversion unit includes a single-phase inverter on a secondary side of a resonant type converter that has an input of a direct current. A power conversion unit group is configured by connecting outputs of the single-phase inverters of a plurality of power conversion units in series. Respective phases of three phase alternate current are formed with the three power conversion unit groups housed in a power conversion device housing. The plurality of power conversion units constituting the power conversion unit group are disposed along a longitudinal direction of the power conversion device housing. The respective three power conversion unit groups are disposed at an upper stage, a middle stage, and a lower stage in a height direction of the power conversion device housing. The power conversion device housing has one end side in the longitudinal direction as output terminals of the three power conversion unit groups. The power conversion device housing has the other end side in the longitudinal direction where terminals of the three power conversion unit groups are connected in common.

Power conversion device, cooling structure, power conversion system, and power supply device

To improve accessibility with respect to a power conversion unit in a power converter. The power converter includes a circuit connection part including a positive electrode conductor, a negative electrode conductor and an AC conductor, a power semiconductor module positioned in a particular direction with respect to the circuit connection part and connected to the positive electrode conductor, the negative electrode conductor and the AC conductor and a capacitor positioned in the particular direction with respect to the circuit connection part and connected to the positive electrode conductor and the negative electrode conductor. The positive electrode conductor is connected to a positive electrode conductor of another power conversion unit through a unit connection part positioned in an opposite direction of the particular direction with respect to the circuit connection part. The negative electrode conductor is connected to a negative electrode conductor of another power conversion unit through the unit connection part.

Power conversion unit, power converter and method of manufacturing power converter

An uninterruptible power-supply system is a power converter having a PN laminated bus bar and a plurality of power conversion units and supplying power from a commercial power supply via a converter and an inverter. The power conversion units each have positive side terminals connected to each other and negative side terminals connected to each other through the PN laminated bus bar. At least one power conversion unit constitutes a phase of the converter. At least another one power conversion unit constitutes a phase of the inverter and has the positive side terminal lying adjacent to and connected through the PN laminated bus bar to the positive side terminal of the corresponding power conversion unit constituting the phase of the converter and the negative side terminal lying adjacent to and connected to the negative side terminal of the corresponding power conversion unit constituting the phase of the converter.

Power conversion device and power conversion method for power conversion device

The present invention reduces the footprint of a power conversion device. A first power semiconductor module and a second power semiconductor module are connected to a positive conductor, a negative conductor, and an alternating-current conductor. An external alternating-current terminal, the first power semiconductor module, the second power semiconductor module, a capacitor, and an external direct-current terminal including an external positive terminal and an external negative terminal are arrayed on a straight line extending in the longitudinal direction of a circuit connection section. The external alternating-current terminal is disposed at one longitudinal end of the circuit connection section. The external direct-current terminal is disposed at the other longitudinal end of the circuit connection section.

Power conversion unit and power conversion device

If an input voltage of a DC/DC converter is lower than a first voltage value that is set in advance, a converter controller maintains an output voltage of the DC/DC converter within a first voltage range that is set in advance by changing an operation frequency of switching of the DC/DC converter in compliance with the input voltage as a first voltage maintaining control. If the input voltage is higher than a second voltage value that is higher than the first voltage value, the converter controller maintains the output voltage within a second voltage range that is higher than the first voltage range by changing the operation frequency in compliance with the input voltage as a second voltage maintaining control.

Power conversion apparatus with frequency operation change based on input voltage

A cooling structure of a heating element includes: the heating element having at least one cooling surface from which a plurality of pin fins project; a heat receiving plate which has a shape complying with the cooling surface and in which holes are formed at positions facing each pin fin, each pin fin being movably inserted into the holes; a cooler which has a pair of clamping members that sandwich therebetween the heating element and the heat receiving plate while pressing the heating element and the heat receiving plate, and which cools the heat receiving plate; and a space securing part which is provided on the heat receiving plate and suppresses a distance between the pair of clamping members so as not to apply a pressing force by the clamping members to the heating element.

Cooling structure of heating element and power conversion device

Reduction in size and weight of transformer for grid tie applications is demanded and can be achieved by applying SST to the transformer. However, SST application to PCS for sunlight requires the following: handle a wide variation range of the voltage of solar power generation; reduce switching losses of power devices, DC/DC converter and inverter, in the power circuit to implement high frequency for SST application; increase voltage to the grid voltage; and reduce the dimensions of the high current path prior to step-up. Thus, LLC resonant converter configuration is applied with an inverter placed in the output, and series connected configuration is applied to the inverter. The LLC resonant converter is subject to constant frequency regulation with large output, step-up control with low output, and step-down control with the upper limit voltage according to MPPT voltage from sunlight, in order to achieve drive loss reduction and voltage range handling.

Power conversion device and power conversion control method for the same

Size and weight reduction of a transformer for system interconnection is needed. Applying an SST to the transformer can reduce the size and weight. However, it is also necessary to flexibly handle a wide range of voltages to match a high-voltage system or motor, reduce switching loss of a power device used in a power circuit such as a DC/DC converter and an inverter in association with frequency increase caused by application of the SST, and achieve size reduction of a cooling structure. Further, it is necessary to boost a voltage to a system voltage and reduce the size and weight of a large current path before the voltage boosting. Thus, an LLC resonant converter structure is applied, and a multiple-connection structure is employed in each of which a converter is arranged for an input or an inverter is arranged for an output. This enables handling of various voltage ranges by various combinations of the numbers of multiple connections of the inputs and the outputs. An insulation cooling structure is provided by a wind-tunnel structure in which two input and output substrates are opposed and are connected by insulation members, and another wind-tunnel structure arranged in the downstream of the wind-tunnel structure and including the LLC resonant structure therein. The wind-tunnel structures are integrated with each other.

Power supply apparatus

A power conversion device capable of reducing a temperature variation between a plurality of semiconductor modules is provided. The power conversion device comprises condensers, a plurality of semiconductor modules, heat dissipation unitsto, a bus barconnecting the condenserswith the plurality of the semiconductor modules, and a ventilation unit having cool wind blow. The power conversion module has features that the plurality of semiconductor modulesare arranged apart from the condensersand in a line in a longitudinal direction of the bus barand that the cool windblows in a direction from the condenserstoward the plurality of semiconductor modulesthat are mounted.

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Tokyo, Japan

Yuuichi Mabuchi