Patents by Inventor Shuta Ishikawa
Shuta Ishikawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 11368019Abstract: An active filter device includes a power module configured to generate a compensating current to suppress a harmonic current generated from a load device and a controller configured to control the power module. The controller includes a current command calculation unit configured to calculate a compensating current command to suppress the harmonic current, a control variable calculation unit configured to calculate a control variable based on a deviation between the compensating current command and an actual compensating current, a duty cycle calculation unit configured to calculate duty cycle of each of three phases based on the control variable, a duty cycle modulation unit configured to perform two-phase modulation on the duty cycle of each of three phases, and a control signal generation unit configured to, after the two-phase modulation, generate, from the duty cycle of each of three phases, a control signal to drive the power module.Type: GrantFiled: April 2, 2019Date of Patent: June 21, 2022Assignee: Mitsubishi Electric CorporationInventors: Shuta Ishikawa, Shusaku Nakase, Keiichi Yamamoto, Keisuke Ishikura
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Patent number: 11349410Abstract: A series multiplex inverter includes a power conversion unit, a phase difference selection unit, a drive signal generation unit, and a drive signal output unit. The phase difference selection unit selects, from among a plurality of phase difference candidates, the phase difference between rectangular wave voltages from a plurality of single-phase inverters. The drive signal generation unit generates a plurality of drive signals that causes the different single-phase inverters to output a plurality of rectangular wave voltages sequentially out of phase by the phase difference selected by the phase difference selection unit. The drive signal output unit outputs the plurality of drive signals generated by the drive signal generation unit to the plurality of single-phase inverters.Type: GrantFiled: January 30, 2018Date of Patent: May 31, 2022Assignee: MITSUBISHI ELECTRIC CORPORATIONInventors: Kazufumi Tanaka, Kazutoshi Kurahashi, Yoshiaki Yamamoto, Shuta Ishikawa
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Publication number: 20220102975Abstract: An active filter device includes a power module configured to generate a compensating current to suppress a harmonic current generated from a load device and a controller configured to control the power module. The controller includes a current command calculation unit configured to calculate a compensating current command to suppress the harmonic current, a control variable calculation unit configured to calculate a control variable based on a deviation between the compensating current command and an actual compensating current, a duty cycle calculation unit configured to calculate duty cycle of each of three phases based on the control variable, a duty cycle modulation unit configured to perform two-phase modulation on the duty cycle of each of three phases, and a control signal generation unit configured to, after the two-phase modulation, generate, from the duty cycle of each of three phases, a control signal to drive the power module.Type: ApplicationFiled: April 2, 2019Publication date: March 31, 2022Inventors: Shuta ISHIKAWA, Shusaku NAKASE, Keiichi YAMAMOTO, Keisuke ISHIKURA
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Patent number: 11233453Abstract: The power conversion device includes a multilevel boosting circuit and a smoothing capacitor for smoothing output voltage of the multilevel boosting circuit. The multilevel boosting circuit includes: a leg portion in which four semiconductor elements, i.e., a first diode, a second diode, a first switching element, and a second switching element are connected in series; and an intermediate capacitor connected between a connection point of the first diode and the second diode, and a connection point of the first switching element and the second switching element. When voltage of the smoothing capacitor becomes a reference voltage value or more, the control unit executes a protection mode to fix the first switching element and the second switching element in OFF states.Type: GrantFiled: August 21, 2018Date of Patent: January 25, 2022Assignee: MITSUBISHI ELECTRIC CORPORATIONInventors: Shuta Ishikawa, Akihiko Iwata, Tatsuki Matsunaga, Koyo Matsuzaki
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Patent number: 11183948Abstract: A series multiplex inverter includes a power conversion unit, a drive signal generation unit, and a drive signal output unit. The drive signal generation unit generates n drive signals that cause different single-phase inverters of n single-phase inverters to output n rectangular wave voltages sequentially out of phase, where n is an integer of three or more. The drive signal output unit outputs the n drive signals to the n single-phase inverters in rotation that shifts, by p every m-fold time of half an output voltage period of the power conversion unit, the single-phase inverters corresponding one-to-one to the n drive signals in a combination of the n drive signals with different single-phase inverters of the n single-phase inverters, where m is a natural number and p is a natural number relatively prime to n or one.Type: GrantFiled: January 29, 2018Date of Patent: November 23, 2021Assignee: MITSUBISHI ELECTRIC CORPORATIONInventors: Kazufumi Tanaka, Kazutoshi Kurahashi, Yoshiaki Yamamoto, Shuta Ishikawa
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Patent number: 11108319Abstract: The power conversion device includes: a boosting unit for boosting DC voltage, the boosting unit including a second switching element, a third switching element, a second reverse-current blocking element, and a third reverse-current blocking element which are connected in series, the boosting unit including an intermediate capacitor connected between a connection point between the second reverse-current blocking element and the third reverse-current blocking element, and a connection point between the third switching element and the second switching element; a smoothing capacitor which is connected in parallel to the boosting unit and smooths the DC voltage boosted by the boosting unit; and a control unit for turning on the third switching element so that the intermediate capacitor is charged to charge completion voltage of the intermediate capacitor.Type: GrantFiled: May 10, 2018Date of Patent: August 31, 2021Assignee: MITSUBISHI ELECTRIC CORPORATIONInventors: Tatsuki Matsunaga, Shuta Ishikawa, Akihiko Iwata
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Publication number: 20210075338Abstract: A series multiplex inverter includes a power conversion unit, a phase difference selection unit, a drive signal generation unit, and a drive signal output unit. The phase difference selection unit selects, from among a plurality of phase difference candidates, the phase difference between rectangular wave voltages from a plurality of single-phase inverters. The drive signal generation unit generates a plurality of drive signals that causes the different single-phase inverters to output a plurality of rectangular wave voltages sequentially out of phase by the phase difference selected by the phase difference selection unit. The drive signal output unit outputs the plurality of drive signals generated by the drive signal generation unit to the plurality of single-phase inverters.Type: ApplicationFiled: January 30, 2018Publication date: March 11, 2021Applicant: Mitsubishi Electric CorporationInventors: Kazufumi TANAKA, Kazutoshi KURAHASHI, Yoshiaki YAMAMOTO, Shuta ISHIKAWA
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Publication number: 20210067054Abstract: A series multiplex inverter includes a power conversion unit, a drive signal generation unit, and a drive signal output unit. The drive signal generation unit generates n drive signals that cause different single-phase inverters of n single-phase inverters to output n rectangular wave voltages sequentially out of phase, where n is an integer of three or more. The drive signal output unit outputs the n drive signals to the n single-phase inverters in rotation that shifts, by p every m-fold time of half an output voltage period of the power conversion unit, the single-phase inverters corresponding one-to-one to the n drive signals in a combination of the n drive signals with different single-phase inverters of the n single-phase inverters, where m is a natural number and p is a natural number relatively prime to n or one.Type: ApplicationFiled: January 29, 2018Publication date: March 4, 2021Applicant: Mitsubishi Electric CorporationInventors: Kazufumi TANAKA, Kazutoshi KURAHASHI, Yoshiaki YAMAMOTO, Shuta ISHIKAWA
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Publication number: 20200287463Abstract: The power conversion device includes a multilevel boosting circuit and a smoothing capacitor for smoothing output voltage of the multilevel boosting circuit. The multilevel boosting circuit includes: a leg portion in which four semiconductor elements, i.e., a first diode, a second diode, a first switching element, and a second switching element are connected in series; and an intermediate capacitor connected between a connection point of the first diode and the second diode, and a connection point of the first switching element and the second switching element. When voltage of the smoothing capacitor becomes a reference voltage value or more, the control unit executes a protection mode to fix the first switching element and the second switching element in OFF states.Type: ApplicationFiled: August 21, 2018Publication date: September 10, 2020Applicant: Mitsubishi Electric CorporationInventors: Shuta ISHIKAWA, Akihiko IWATA, Tatsuki MATSUNAGA, Koyo MATSUZAKI
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Publication number: 20200287458Abstract: The power conversion device includes: a boosting unit for boosting DC voltage, the boosting unit including a second switching element, a third switching element, a second reverse-current blocking element, and a third reverse-current blocking element which are connected in series, the boosting unit including an intermediate capacitor connected between a connection point between the second reverse-current blocking element and the third reverse-current blocking element, and a connection point between the third switching element and the second switching element; a smoothing capacitor which is connected in parallel to the boosting unit and smooths the DC voltage boosted by the boosting unit; and a control unit for turning on the third switching element so that the intermediate capacitor is charged to charge completion voltage of the intermediate capacitor.Type: ApplicationFiled: May 10, 2018Publication date: September 10, 2020Applicant: Mitsubishi Electric CorporationInventors: Tatsuki MATSUNAGA, Shuta ISHIKAWA, Akihiko IWATA
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Patent number: 10756629Abstract: A converter supplies an output voltage, generated by stepping down or up an input voltage from a DC power supply, to an inverter for driving an AC motor. In the converter in a boost mode, a buck circuit is stopped, a boost circuit is operated, and a first bypass switch is turned on to form a path from the DC power supply to the boost circuit. In a buck mode, the boost circuit (30) is stopped, the buck circuit is operated, and a second bypass switch is turned on to form a path from the buck circuit to the inverter.Type: GrantFiled: November 21, 2017Date of Patent: August 25, 2020Assignee: MITSUBISHI ELECTRIC CORPORATIONInventors: Shuta Ishikawa, Akihiko Iwata, Tatsuki Matsunaga
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Patent number: 10720850Abstract: A series connection body wherein a first backflow prevention elements, a second backflow prevention element, a first switching element and a second switching element are connected in series in this order; a reactor; a first output capacitor connected between a first end of the series connection body and a second end of the series connection body; and a second output capacitor connected between a connection point between the first switching element and the second switching element and a connection point between the first backflow prevention element and the second backflow prevention element are provided, a DC is inputted between an end of the reactor and the second end section of the series connection body, and power is supplied to a first load connected to both ends of the first output capacitor and a second load connected to both ends of the second output capacitor.Type: GrantFiled: October 4, 2017Date of Patent: July 21, 2020Assignee: MITSUBISHI ELECTRIC CORPORATIONInventors: Shuta Ishikawa, Akihiko Iwata, Tatsuki Matsunaga
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Publication number: 20200099300Abstract: A converter supplies an output voltage, generated by stepping down or up an input voltage from a DC power supply, to an inverter for driving an AC motor. In the converter in a boost mode, a buck circuit is stopped, a boost circuit is operated, and a first bypass switch is turned on to form a path from the DC power supply to the boost circuit. In a buck mode, the boost circuit (30) is stopped, the buck circuit is operated, and a second bypass switch is turned on to form a path from the buck circuit to the inverter.Type: ApplicationFiled: November 21, 2017Publication date: March 26, 2020Applicant: Mitsubishi Electric CorporationInventors: Shuta ISHIKAWA, Akihiko IWATA, Tatsuki MATSUNAGA
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Publication number: 20190334445Abstract: A series connection body wherein a first backflow prevention elements, a second backflow prevention element, a first switching element and a second switching element are connected in series in this order; a reactor; a first output capacitor connected between a first end of the series connection body and a second end of the series connection body; and a second output capacitor connected between a connection point between the first switching element and the second switching element and a connection point between the first backflow prevention element and the second backflow prevention element are provided, a DC is inputted between an end of the reactor and the second end section of the series connection body, and power is supplied to a first load connected to both ends of the first output capacitor and a second load connected to both ends of the second output capacitor.Type: ApplicationFiled: October 4, 2017Publication date: October 31, 2019Applicant: Mitsubishi Electric CorporationInventors: Shuta ISHIKAWA, Akihiko IWATA, Tatsuki MATSUNAGA
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Patent number: 10379070Abstract: An A/D converter converts an output from a temperature sensor into a digital signal. A service life diagnostic unit diagnoses a service life of a power module based on a signal indicating a temperature outputted from the A/D converter. An output unit generates a signal representing a diagnostic result and outputs the generated signal from an output terminal to outside.Type: GrantFiled: February 19, 2014Date of Patent: August 13, 2019Assignee: Mitsubishi Electric CorporationInventors: Shuta Ishikawa, Teruaki Tanaka
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Patent number: 10263539Abstract: A power converter includes a transformation circuit configured to transform a rectified voltage, and a converter control unit configured to control a switching element of the transformation circuit. The converter control unit calculates a current command value based on a line voltage or the phase voltage, calculates a current deviation between the current command value and the reactor current, and calculates a switching command value from the current deviation. The converter control unit includes a plurality of integrators for the respective different phase angles of a power supply voltage. The integrator corresponding to a power supply phase angle is caused to accumulate the current deviation, and the integrator corresponding to a phase angle that is advanced by a set delay phase from the power supply phase angle is caused to output the control amount. A switching signal is generated with use of the control amount and the switching command value.Type: GrantFiled: October 1, 2015Date of Patent: April 16, 2019Assignee: Mitsubishi Electric CorporationInventors: Kenta Yuasa, Shuta Ishikawa, Akihiro Tsumura, Shinsaku Kusube
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Publication number: 20180287490Abstract: A power converter includes a transformation circuit configured to transform a rectified voltage, and a converter control unit configured to control a switching element of the transformation circuit. The converter control unit calculates a current command value based on a line voltage or the phase voltage, calculates a current deviation between the current command value and the reactor current, and calculates a switching command value from the current deviation. The converter control unit includes a plurality of integrators for the respective different phase angles of a power supply voltage. The integrator corresponding to a power supply phase angle is caused to accumulate the current deviation, and the integrator corresponding to a phase angle that is advanced by a set delay phase from the power supply phase angle is caused to output the control amount. A switching signal is generated with use of the control amount and the switching command value.Type: ApplicationFiled: October 1, 2015Publication date: October 4, 2018Inventors: Kenta YUASA, Shuta ISHIKAWA, Akihiro TSUMURA, Shinsaku KUSUBE
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Patent number: 9871482Abstract: A power conversion device includes a high-pass filter for extracting an AC component of voltage Vdc of a DC link section, a multiplier for multiplying output VdcAC of the high-pass filter by a first gain K1 and outputting the result, a multiplier for multiplying output of the multiplier by a second gain K2 and outputting the result as a d-axis voltage correction signal vdcmp*, and a multiplier for multiplying output of the multiplier by a third gain K3 and outputting the result as a q-axis voltage correction signal vqcmp*. The gate signal generation section generates gate signals on the basis of a signal vd1 obtained by adding the d-axis voltage correction signal vdcmp* to a d-axis voltage command value vd* and a signal vq1 obtained by adding the q-axis voltage correction signal vqcmp* to a q-axis voltage command value vq*.Type: GrantFiled: June 15, 2015Date of Patent: January 16, 2018Assignee: Mitsubishi Electric CorporationInventors: Shuta Ishikawa, Masanori Kato, Shotaro Marumoto, Ryuichi Takezawa, Shunichi Nishimura
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Publication number: 20170264225Abstract: A power conversion device includes a high-pass filter for extracting an AC component of voltage Vdc of a DC link section, a multiplier for multiplying output VdcAC of the high-pass filter by a first gain K1 and outputting the result, a multiplier for multiplying output of the multiplier by a second gain K2 and outputting the result as a d-axis voltage correction signal vdcmp*, and a multiplier for multiplying output of the multiplier by a third gain K3 and outputting the result as a q-axis voltage correction signal vqcmp*. The gate signal generation section generates gate signals on the basis of a signal vd1 obtained by adding the d-axis voltage correction signal vdcmp* to a d-axis voltage command value vd* and a signal vq1 obtained by adding the q-axis voltage correction signal vqcmp* to a q-axis voltage command value vq*.Type: ApplicationFiled: June 15, 2015Publication date: September 14, 2017Applicant: Mitsubishi Electric CorporationInventors: Shuta ISHIKAWA, Masanori KATO, Shotaro MARUMOTO, Ryuichi TAKEZAWA, Shunichi NISHIMURA
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Patent number: 9748829Abstract: A power module including: a power conversion unit including N switching-element pairs; and a control circuit. The control circuit receives N command signals, which correspond respectively to the N switching-element pairs, and a shared enable signal. The control circuit is configured to, when the enable signal is negated, execute all-off control of turning off all of the switching elements constituting the power conversion unit, and when the enable signal is asserted, execute normal control, dead-time addition control, and dead-time compensation control for each of the switching-element pairs per period of a corresponding command signal.Type: GrantFiled: January 31, 2014Date of Patent: August 29, 2017Assignee: Mitsubishi Electric CorporationInventors: Satoshi Azuma, Shuta Ishikawa, Teruaki Tanaka