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公开(公告)号：US12199524B2
公开(公告)日：2025-01-14
申请号：US17759875
申请日：2020-03-11
Applicant: Mitsubishi Electric Corporation
Inventor： Takuya Kajiyama , Toshiyuki Fujii , Shuhei Fujiwara , Ryosuke Uda , Yoshiyuki Kono
Abstract: A power conversion device includes a plurality of leg circuits and a control device. The control device controls an output voltage at a first converter cell, which is controlled not based on the circulating current, based on a first voltage instruction value. The control device controls an output voltage at a second converter cell using a first value based on a deviation between a circulating current and a circulating current instruction value and a second value based on a deviation between a capacitor voltage and a capacitor voltage instruction value in the second converter cell. When the capacitor voltage at the second converter cell is less than a first threshold, the control device linearly combines an auxiliary voltage instruction value including at least one of a DC component and a fundamental AC component of the AC circuit with the first value and the second value.
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公开(公告)号：US12068610B2
公开(公告)日：2024-08-20
申请号：US17603471
申请日：2019-04-25
Applicant: Mitsubishi Electric Corporation
Inventor： Ryosuke Uda , Takeshi Kikuchi , Shuhei Fujiwara , Yoshiyuki Kono
CPC classification number: H02J3/388 , H02J3/36 , H02M1/0025
Abstract: A control device includes: a phase error calculation unit to calculate a phase error between a phase of a voltage command for the power converter and a phase of a point-of-interconnection voltage; and an isolated system determination unit to determine whether the AC power system has shifted from an interconnected system to an isolated system, based on the phase error and a magnitude of the point-of-interconnection voltage, the interconnected system being the AC power system connected to a generator, the isolated system being the AC power system not connected to the generator. The isolated system determination unit determines that the AC power system has shifted from the interconnected system to the isolated system, when at least a first condition is met that the phase error is outside a reference range and the magnitude of the point-of-interconnection voltage is greater than a first voltage threshold.
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公开(公告)号：US10707790B2
公开(公告)日：2020-07-07
申请号：US15547318
申请日：2015-12-02
Inventor： Masayuki Hashimoto , Tsuyoshi Wakasa , Yoshiyuki Kono , Shuhei Fujiwara
Abstract: The present electric power generation control device includes: an event detection unit which detects an event attributable to a deterioration in the balance between a torque input to a generator and an effective power output by the generator, the deterioration being caused by a reduction in a set value of the effective power received from the generator by an electric power converter when the electric power converter has detected a failure necessitating interruption of electric power transmission from the generator by a direct-current (DC) power transmission unit, the DC power transmission unit transmitting DC power, the electric power converter connecting a generator to the DC power transmission unit; and a torque command reduction unit which causes a reduction in a torque command to a motor when the event detection unit has detected the event attributable to the deterioration in the balance, the motor outputting the torque input to the generator.
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公开(公告)号：US12057787B2
公开(公告)日：2024-08-06
申请号：US17793697
申请日：2020-03-11
Applicant: Mitsubishi Electric Corporation
Inventor： Takuya Kajiyama , Toshiyuki Fujii , Shuhei Fujiwara , Ryosuke Uda , Yoshiyuki Kono
CPC classification number: H02M7/49 , H02M7/217 , H02M1/0009
Abstract: A power conversion device includes a power conversion circuit unit including a plurality of leg circuits, and a control device. Each of the leg circuits includes a plurality of first converter cells each having a capacitor and connected in series to each other and a plurality of second converter cells each having the capacitor and connected in series to each other. The plurality of first converter cells are controlled not based on a circulating current circulating between the plurality of leg circuits, and the plurality of second converter cells are controlled based on the circulating current. The control device stops a switching operation of at least one second converter cell in the plurality of second converter cells when a voltage at the capacitor in the second converter cell becomes less than a first threshold.
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公开(公告)号：US11309787B2
公开(公告)日：2022-04-19
申请号：US16635297
申请日：2018-06-05
Applicant: Mitsubishi Electric Corporation
Inventor： Yoshiyuki Kono , Shuhei Fujiwara , Ryosuke Uda , Shigeo Hayashi
Abstract: A power conversion device includes a conversion circuit constituted of a plurality of arm circuits and a bypass circuit. The bypass circuit includes a full-wave rectification circuit, a positive-side connection arm, and a negative-side connection arm. The full-wave rectification circuit is connected between a plurality of AC connections, a positive-side intermediate node, and a negative-side intermediate node, and configured to convert AC voltages generated at the plurality of AC connections into a DC voltage across the positive-side intermediate node and the negative-side intermediate node and output the DC voltage. The positive-side connection arm blocks a current in a direction from a positive-side DC terminal toward the positive-side intermediate node. The negative-side connection arm is connected between the negative-side intermediate node and a negative-side DC terminal and blocks a current in a direction from the negative-side intermediate node toward a negative-side DC terminal.
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Patent Agency Ranking
公开(公告)号：US11031882B2
公开(公告)日：2021-06-08
申请号：US16500143
申请日：2017-05-26
Applicant: Mitsubishi Electric Corporation
Inventor： Kazuyori Tahata , Yoshiyuki Kono , Kenichi Kuroda , Shuhei Fujiwara , Ryosuke Uda
Abstract: A power conversion device includes power conversion circuitry including a plurality of submodules connected in series to each other. The power conversion device further includes: a signal reception unit configured to receive a signal representing a voltage of a capacitor in each of the submodules; a time calculation unit configured to calculate at least one of a charging time of the capacitor and a discharging time of the capacitor based on the signal; and a determination unit configured to determine whether the capacitor has degraded or not based on at least one of a first result of comparison of the charging time with a reference charging time serving as a reference for determining degradation of the capacitor, and a second result of comparison of the discharging time with a reference discharging time serving as a reference for determining degradation of the capacitor.
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公开(公告)号：US20190068076A1
公开(公告)日：2019-02-28
申请号：US16079861
申请日：2016-03-28
Applicant: MITSUBISHI ELECTRIC CORPORATION
Inventor： Ryosuke Uda , Kenichi Kuroda , Masashi Kitayama , Yoshiyuki Kono , Shigeo Hayashi
Abstract: Each arm circuit of a power conversion device includes a plurality of cascaded cell blocks and a plurality of bypass circuits connected in parallel to the respective cell blocks. Each cell block includes: a first connection node on a high potential side and a second connection node on a low potential side for connection to another cell block; and a plurality of converter cells cascaded between the first and second connection nodes, each converter cell containing an energy storage. The plurality of converter cells include at least one first converter cell of a full-bridge (or hybrid) configuration and at least one second converter cell of a half-bridge configuration.
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公开(公告)号：US12074535B2
公开(公告)日：2024-08-27
申请号：US17439574
申请日：2019-04-25
Applicant: Mitsubishi Electric Corporation
Inventor： Ryosuke Uda , Takeshi Kikuchi , Shuhei Fujiwara , Yoshiyuki Kono
CPC classification number: H02M7/4835 , H02J3/36 , H02J3/388 , H02M1/0025 , H02M7/79
Abstract: A control device includes: a phase generation unit to generate a phase of a voltage command for the power converter; a voltage control unit to generate a voltage value of the voltage command; and a command unit to output the voltage command having the phase and the voltage value to the power converter. The voltage control unit includes: a voltage compensator unit to compute a compensation voltage value, based on a voltage deviation of a point-of-interconnection voltage from a reference voltage; a droop calculator unit to compute a first droop value in accordance with a magnitude of a point-of-interconnection current, when the AC power system is an isolated system, the isolated system being the AC power system not connected to a generator; and a calculation unit to calculate the voltage value of the voltage command, based on a difference between the compensation voltage value and the first droop value.
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公开(公告)号：US11283369B2
公开(公告)日：2022-03-22
申请号：US17044582
申请日：2018-06-07
Applicant: Mitsubishi Electric Corporation
Inventor： Shuhei Fujiwara , Yoshiyuki Kono , Kazuyori Tahata , Masashi Shigemitsu , Shota Midorikawa
Abstract: A control device for controlling a power source connected to an alternating-current (AC) power system includes: a frequency control unit that controls a frequency of the power source operating in a constant-voltage constant-frequency control scheme; a power calculation unit that calculates, when the frequency control unit varies a frequency of the power source, a variation of an effective power output from the power source; an arithmetic unit that calculates a frequency characteristics constant of the AC power system, based on a variation of the frequency of the power source and the variation of the effective power output from the power source; and a selection unit that selects a control scheme for the power source, based on the frequency characteristics constant of the AC power system.
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公开(公告)号：US12081138B2
公开(公告)日：2024-09-03
申请号：US17797272
申请日：2020-03-11
Applicant: Mitsubishi Electric Corporation
Inventor： Takuya Kajiyama , Toshiyuki Fujii , Shuhei Fujiwara , Ryosuke Uda , Yoshiyuki Kono
Abstract: A power conversion device includes a power conversion circuit unit including a plurality of leg circuits. Each of the leg circuits includes a plurality of converter cells each having a capacitor and connected in series to each other. Each of the plurality of converter cells is a first converter cell including at least two switching elements or a second converter cell including at least four switching elements. The power conversion device further includes a control device. The control device operates the plurality of the first converter cells that are controlled not based on a circulating current circulating between the plurality of leg circuits as a voltage source that outputs a circulating voltage in a circulation circuit indicating a closed circuit that does not include a DC circuit and an AC circuit, and operates the plurality of the second converter cells to control the circulating current in the circulation circuit.
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