Sumitomo Electric Industries, Limited

Other

Japan Atomic Energy Research Institute

Naoki Ayai

Tetsuo Akita

Toshiaki Okumura

Kazuhiko Hayashi

Yusuke Shimizu

Kenji Abiru

Takeshi Hikata

Ryosuke Hata

Akira Mikumo

Munetsugu Ueyama

Tetsuyuki Kaneko

Yuichi Yamada

Hiromi Takei

Koichi Takeshita

Yoshiharu Nakajima

Kenichi Takahashi

Hiroshi Maeda

Hiroshi Tsuji

Mitsunori Sato

Jun Fujikami

Toshinari Ando

Nobuhiro Saga

Hiroyasu Yumura

Shinichi Kobayashi

Fumio Urakawa

Shin-ichi Kobayashi

Tomohiro Yamaguchi

Mitsuyasu Ueda

Shin-ichi Kobayasi

Makoto Sugimoto

Norikiyo Koizumi

Takashi Fumino

Yuji Okuda

Shinjirou Shinada

Tadatsugu Udono

An inverter according to the present disclosure is an inverter connected in parallel to an alternating-current circuit to which an alternating-current power source is connected, and configured to provide an independent output to the alternating-current circuit. The inverter includes a power converter configured to convert a direct-current power into an alternating-current power to supply power to the alternating-current circuit, a voltage sensor configured to detect an alternating-current voltage of the alternating-current circuit, and a controller configured to control the power converter. The controller is configured to add frequency feedback processing to an operation of calculating a frequency detection value in a phase locked loop to be executed based on the alternating-current voltage, the frequency feedback processing being processing of adding a frequency correction value obtained by performing a proportional integral operation on a comparison result between a previous value of the frequency detection value and a frequency reference value.

Inverter, parallel inverter system, and method of controlling inverter

This DC/DC conversion system is provided between a plurality of DC power supplies and a common DC bus, and includes, for each of the plurality of DC power supplies: a DC/DC converter provided between the DC power supply and the DC bus; and a control unit configured to control the DC/DC converter. The control unit corrects a voltage detection value for the DC bus by taking in an individual voltage detection deviation for the DC bus compared to an entirety of a plurality of the DC/DC converters present in parallel, and controls the corresponding DC/DC converter in accordance with a voltage command value having droop characteristics with respect to output power. The DC/DC conversion system as described above can uniform outputs while operating the plurality of DC/DC converters in parallel without the need of fast communication.

DC/DC conversion system, electricity storage system, and method for controlling DC/DC converter

In a High Efficient and Reliable Inverter Concept power conversion device, control is performed with one cycle divided into four periods, wherein in a first period when the signs of an AC voltage and an AC current are both positive, first and fourth switches perform switching operation, second and third switches are opened, and a sixth switch is closed; in a second period when the signs are positive and negative, a current is passed through freewheeling diodes when a fifth switch is opened while the fifth switch performs switching operation; in a third period when both signs are negative, the second and third switches perform switching operation, the first and fourth switches are opened, and the fifth switch is closed; and in a fourth period when the signs are negative and positive, a current is passed through freewheeling diodes when the sixth switch is opened while the sixth switch performs switching operation.

Power converter for performing conversion from DC to AC or vice versa, and method for controlling the power converter

A power storage device according to an aspect of the present disclosure includes: a casing including a bottom wall and a top wall opposite to the bottom wall; a storage battery; an electrical unit; and a cooling unit. The storage battery is disposed in the casing and separated from the bottom wall. The electrical unit is disposed in the casing and located closer to the top wall than the storage battery is. A first fan is disposed between the storage battery and the electrical unit and configured to direct air from the storage battery toward the electrical unit.

Power storage device

This power conversion system is composed of a DC power supply circuit and a power conditioner which are connected to each other. The power conditioner includes: a first DC/DC converter provided between the DC power supply circuit and a DC bus; and an inverter provided between the DC bus and an AC electric path and configured to perform switching operation in such a manner that the inverter and the first DC/DC converter alternately have stop periods in an AC half cycle. The DC power supply circuit includes: a storage battery; and a second DC/DC converter of a bidirectional type, provided between the storage battery and the first DC/DC converter and including a DC reactor. The power conversion system includes a control unit configured to control current flowing through the DC reactor of the second DC/DC converter to have a constant value.

Power conversion system and control method therefor

This power supply device includes: a power interconnection path connecting a power interconnection port to a power conversion unit via a first switch; a stand-alone power supply path leading from an auxiliary input port via a second switch to an output port to which a load is connected; a storage-battery-side power supply path leading from a storage battery via the power conversion unit to the output port; and a control unit, the control unit causing the power conversion unit to charge/discharge the storage battery when interconnected with a commercial power grid, the control unit supplying power to the load via one of the stand-alone power supply path and the storage-battery-side power supply path when disconnected from the commercial power grid, the control unit switching the power supply path from the one to the other within an extremely short time period such as not to influence the load.

Power supply device and power supply system

This power conversion device includes: a power conversion unitprovided between a DC power supplyand an AC electric pathand configured to perform DC/AC power conversion; and a control unitconfigured to control the power conversion unit. The control unitincludes a determination unitconfigured to determine whether or not a starting current has flowed through the AC electric path, and an adjustment unitconfigured to adjust an AC voltage generated by the power conversion unit, on the basis of a result of the determination by the determination unit

Power conversion device and control method for power conversion device

This conversion device includes: a DC bus with a smoothing capacitor; a first converter provided between a DC power supply and the DC bus to perform DC/DC conversion; a second converter provided between the DC bus and an AC electric path to perform DC/AC or AC/DC conversion by a full-bridge of switching elements; a voltage sensor for detecting voltage between both ends of the capacitor as DC bus voltage; and a control unit which causes a part of an absolute value of an AC waveform, and a DC waveform, to alternately arise as the DC bus voltage by selectively causing the first converter and the second converter to operate in one AC cycle of the AC electric path, the control unit detecting arm short-circuit in the second converter on the basis of a degree of reduction, in the DC bus voltage, that occurs during operation of the second converter.

Conversion device having a control unit for detecting arm short-circuit

A power conversion device includes a switch connected to an AC system; an AC/DC converter; and a DC/DC converter. A control unit compares an absolute value of an AC voltage target value based on the AC voltage with a DC voltage target value based on the storage battery voltage, and executes, on the basis of a magnitude relation of the values, a control method such that a period during which step-up operation is performed through switching operation mainly using one of the AC/DC converter and the DC/DC converter, and a period during which step-down operation is performed through switching operation mainly using the other one of the converters, alternately arise. When starting charging/discharging of the storage battery, the control unit causes the switch to close at zero cross timing of the AC voltage, and thereafter, causes charging/discharging to start from the switching operation through which the step-down operation is performed.

Power conversion device and method for controlling same

A power conversion device provided between a DC power supply and an AC electric path, including: a breaking device provided to at least one line of an output electric path in the power conversion device; a first voltage sensor provided on a primary side of the breaking device; a second voltage sensor provided on a secondary side of the breaking device; and a determination unit which calculates a primary-side voltage and a secondary-side voltage, and a primary-side phase and a secondary-side phase and determines that the breaking device is opened, by occurrence of an event in which an absolute value of a voltage difference between the primary-side voltage and the secondary-side voltage is greater than a voltage difference threshold value and an absolute value of a phase difference between the primary-side phase and the secondary-side phase is greater than a phase difference threshold value.

Power conversion device and method for determining operational state of breaking device

A control unit of a power conversion device calculates a current target value and a voltage target value for a DC/AC converter on the basis of an output current target value, to control the DC/AC converter, and calculates a current target value for the DC/DC converter on the basis of the current target value and the voltage target value, and a voltage target value for the DC/DC converter, to control the DC/DC converter, thereby controlling output of an AC power. The control unit selects, as the voltage target value for the DC/DC converter, a greatest value at a present time, from among a DC voltage value of the DC power supply, an absolute value of a voltage target value for an AC side of the DC/AC converter, and a DC voltage lower limit value which is a predetermined value smaller than a peak value of the absolute value.

Power conversion device and control method for same

This power supply device includes: an AC path from an input end to an output end; a current sensor configured to detect a current flowing through the AC path; a conversion unit connected to the AC path and being capable of bidirectional power conversion; a storage battery connected to the AC path via the conversion unit; an AC switch provided between the input end and a point at which the conversion unit is connected to the AC path, the AC switch including parallel body of a relay contact and a semiconductor switch; and a control unit configured to control the conversion unit and the AC switch. When the control unit executes a current conduction mode for the first time, and when the current sensor detects an excessive current during the current conduction mode, the control unit closes only the relay contact while keeping the semiconductor switch opened.

Power supply device and switch control method therefor

This conversion device converts DC powers from a plurality of DC power supplies, to AC power and supplies the AC power to a load. The conversion device includes: a filter circuit including an AC reactor and a first capacitor; a DC/AC inverter connected to the load via the filter circuit; DC/DC converters provided between the respective plurality of DC power supplies and the DC/AC inverter; a second capacitor provided between the DC/AC inverter and the DC/DC converters; and a control unit configured to set a current target value for each of the DC/DC converters to thereby be synchronized with current of the AC power, based on voltage of the AC power, voltage variation due to current flowing through the AC reactor and an impedance thereof, reactive currents respectively flowing through the first capacitor and the second capacitor, and voltage of each DC power.

Conversion device

This power supply unit includes: an AC path from an input end to an output end; a first voltage sensor configured to detect an input voltage at the input end; a second voltage sensor configured to detect an output voltage at the output end; a bidirectional inverter connected to the AC path; a storage battery connected to the AC path via the bidirectional inverter; an AC switch provided between the input end and a point at which the bidirectional inverter is connected to the AC path; and a control unit configured such that, in a state in which the AC switch is controlled to be opened, if current conduction via the AC switch is detected on the basis of an operation state of the bidirectional inverter, the input voltage, and the output voltage, the control unit determines that the AC switch has failed, and stops the bidirectional inverter.

Power supply unit and method for backfeed protection thereof

Duties of control for DC/AC and DC/DC conversion units are determined by considering electric influences of a filter circuit, a capacitor connected to a DC bus, and a DC reactor for an output voltage command value for supplying an AC voltage to a load. The DC/DC conversion unit is controlled to convert a DC voltage into a DC bus voltage waveform alternately having a period of a pulsating current waveform corresponding to the absolute value of the AC voltage and a period of the DC voltage as a pulsating current minimum value. The DC/AC conversion unit is controlled to perform step-down operation during the period of the DC voltage and thus perform conversion into a waveform of the absolute value of the AC voltage corresponding to the period of the DC voltage, and also to perform polarity inversion per one pulsating current cycle.

Growing community of inventors

Osaka, Japan

Naoki Ayai