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公开(公告)号：US20240146066A1
公开(公告)日：2024-05-02
申请号：US18557342
申请日：2021-06-01
Applicant: Mitsubishi Electric Corporation
Inventor： Frederick PAGE , Yoshiyuki KONO , Kazuyori TAHATA , Shuhei FUJIWARA , Shinji TOMINAGA , Masatoshi TAKEDA
CPC classification number: H02J3/32 , H02J3/14 , H02J3/16 , H02M1/007 , H02M3/33584 , H02M7/043 , H02J3/38
Abstract: In a power grid stabilization system, a second energy storage system has a larger energy storage capacity than a first energy storage system. A bidirectional AC/DC converter is connected between an AC power grid and a pair of input and output terminals of the first energy storage system. A first bidirectional DC/DC converter is connected between the pair of input and output terminals of the first energy storage system and a pair of input and output terminals of the second energy storage system.
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公开(公告)号：US20210099102A1
公开(公告)日：2021-04-01
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：US20240305188A1
公开(公告)日：2024-09-12
申请号：US18254683
申请日：2020-12-09
Applicant: Mitsubishi Electric Corporation
Inventor： Takuya KAJIYAMA , Toshiyuki FUJII , Shuhei FUJIWARA , Kazuyori TAHATA
Abstract: In a power conversion device, each of a plurality of converter cells includes a pair of input/output terminals, a plurality of switching elements, and a power storage element electrically connected to the input/output terminals through the switching elements. A current-limiting resistor is connected to a path of AC output current of the power converter. A bypass switch is connected in parallel with the current-limiting resistor. A short circuit switch short-circuits an AC line between an AC circuit breaker and the current-limiting resistor. In a discharge operation mode, a control device performs power conversion operation by allowing switching of each switching element of each of the converter cells in a state in which the AC circuit breaker and the bypass switch are opened and the short circuit switch is closed.
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公开(公告)号：US20240088673A1
公开(公告)日：2024-03-14
申请号：US18261927
申请日：2021-02-05
Applicant: Mitsubishi Electric Corporation
Inventor： Kazuyori TAHATA , Yoshiyuki KONO , Shuhei FUJIWARA , Shinji TOMINAGA
Abstract: An electric power control system includes a plurality of power converters connected in parallel. Each power converter, among the plurality of power converters, converts a direct-current power of an electricity storage device connected to the power converter into an alternating-current power, and outputs the alternating-current power to the power system. The electric power control system further includes: a power generator simulation unit to simulate characteristics of the synchronous generator based on an aggregate active power to generate a phase of the alternating-current voltage; a signal generation unit to generate a control signal for the power converter, based on the phase of the alternating-current voltage. The power generator simulation unit generates a first angular frequency based on a first difference between the aggregate active power and a target value for the aggregate active power, and generates, based on the first angular frequency, the phase of the alternating-current voltage.
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公开(公告)号：US20210021210A1
公开(公告)日：2021-01-21
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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Patent Agency Ranking
公开(公告)号：US20250015596A1
公开(公告)日：2025-01-09
申请号：US18712384
申请日：2022-02-04
Applicant: Mitsubishi Electric Corporation
Inventor： Frederick PAGE , Kazuyori TAHATA
Abstract: A power control system includes: a first energy storage system; a bidirectional AC/DC converter connected between an AC power system and the first energy storage system; and a control device for controlling an operation of the bidirectional AC/DC converter. The control device controls the operation of the bidirectional AC/DC converter to control charging and discharging of the first energy storage system. The power control system includes: a circuit breaker connected between the AC power system and the bidirectional AC/DC converter; a resistor connected between the circuit breaker and the bidirectional AC/DC converter; and a switch for forming a discharge path for discharging the DC power of the first energy storage system via the resistor, while the circuit breaker is open.
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公开(公告)号：US20250015595A1
公开(公告)日：2025-01-09
申请号：US18705633
申请日：2021-11-22
Applicant: Mitsubishi Electric Corporation
Inventor： Kazuyori TAHATA , Frederick PAGE , Yoshiyuki KONO , Masatoshi TAKEDA
Abstract: A frequency stabilizer includes a bidirectional AC/DC converter, a bidirectional DC/DC converter, a first energy storage system, a second energy storage system, and a building. The bidirectional AC/DC converter is connected between an AC power system and the first energy storage system. The bidirectional DC/DC converter is connected between the first energy storage system and the second energy storage system. Two or more of the first energy storage system, the second energy storage system, the bidirectional AC/DC converter, and the bidirectional DC/DC converter are disposed inside the building.
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公开(公告)号：US20240022183A1
公开(公告)日：2024-01-18
申请号：US18254584
申请日：2020-12-09
Applicant: Mitsubishi Electric Corporation
Inventor： Takuya KAJIYAMA , Toshiyuki FUJII , Shuhei FUJIWARA , Kazuyori TAHATA
IPC: H02M7/5395 , H02M7/483 , H02M1/00
CPC classification number: H02M7/5395 , H02M7/4835 , H02M1/0054 , H02M1/0012
Abstract: A power conversion device includes a power converter including a plurality of arms each having a plurality of converter cells cascaded to each other. A control device includes an AC current controller to control AC current flowing between the power converter and an AC circuit and a circulating current controller to control circulating current flowing between the arms of the power converter. The AC current controller reduces an effective value or amplitude value of AC current in a discharge operation mode in which a voltage of a power storage element of each converter cell is discharged, compared with in a normal operation mode. The circulating current controller increases an effective value or amplitude value of circulating current in the discharge operation mode, compared with in the normal operation mode.
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公开(公告)号：US20220029524A1
公开(公告)日：2022-01-27
申请号：US17292905
申请日：2018-12-25
Applicant: Mitsubishi Electric Corporation
Inventor： Takuya KAJIYAMA , Toshiyuki FUJII , Shuhei FUJIWARA , Ryosuke UDA , Kazuyori TAHATA
IPC: H02M1/12 , H02M7/49 , H02M1/32 , H02M7/5387
Abstract: A power converter includes an arm in which a plurality of converter cells are connected in series, each of the converter cells including at least two switching elements, a power storage element, and a pair of output terminals. A control device controls the power converter. The converter cell includes a switch to have the converter cell bypassed. When the control device senses failure of the converter cell, it has the failed converter cell within the arm bypassed and controls a normal converter cell within the arm to suppress a ratio of a harmonic component in an arm current that increases due to the failure.
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公开(公告)号：US20190027327A1
公开(公告)日：2019-01-24
申请号：US16072244
申请日：2016-02-05
Applicant: MITSUBISHI ELECTRIC CORPORATION
Inventor： Kazuyori TAHATA , Kunio KIKUCHI , Makoto MIYASHITA , Kenji KAMEI , Sho TOKOYODA
Abstract: A direct current circuit breaker used in a self-commutated direct current power transmission system includes a high-speed circuit breaker and a low-speed circuit breaker connected in series. The high-speed circuit breaker includes a high-speed circuit breaker interruption unit to interrupt a DC current flowing through a direct current line when a fault has occurred, and a current limiting element connected in parallel therewith. The low-speed circuit breaker includes a low-speed circuit breaker interruption unit to interrupt a DC current when a fault has occurred. A time required for the high-speed circuit breaker interruption unit to interrupt the DC current is shorter than a time required for the low-speed circuit breaker interruption unit. The low-speed circuit breaker interruption unit completes interruption of the DC current before a voltage applied to the current limiting element becomes lower than a minimum voltage allowable for the system.
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