Patents by Inventor Fujio Kurokawa
Fujio Kurokawa 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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Publication number: 20230152375Abstract: Provided is a deterioration estimation device and a deterioration estimation program for a power conversion device that can estimate the deterioration of a switching element without providing a special sensor. A deterioration estimation device includes a calculating device calculating the variation of the characteristics of an IGBT in an inverter from a voltage command treated as a target of the output voltage of the power conversion device and the output voltage value of the power conversion device, a determining device determining whether the variation of the characteristics calculated by the calculating device has changed from an initial state by a threshold value or greater, and a notifying device issuing a warning when the determining device has determined that the change in the variation of the characteristics is equal to or greater than the threshold value.Type: ApplicationFiled: March 31, 2021Publication date: May 18, 2023Applicants: NAGASAKI INSTITUTE OF APPLIED SCIENCE, TOSHIBA MITSUBISHI-ELECTRIC INDUSTRIAL SYSTEMS CORPORATIONInventors: Fujio KUROKAWA, Ritaka NAKAMURA, Hajime SHIRAISHI
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Patent number: 10707764Abstract: A power apparatus includes a power circuit configured to receive an input voltage and generate an output voltage, a memory, and a processor coupled to the memory and the processor configured to calculate an integral value of an error between the output voltage and a target voltage of the power circuit, calculate a duty ratio based on the integral value, the power circuit being controlled according to the calculated duty ratio so that the output voltage becomes the target voltage, calculate a slope of the integral value with respect to an output current of the power circuit, and generate a first warning signal when the calculated slope exceeds a first warning threshold in a case where the calculated slope is different from an initial value.Type: GrantFiled: July 18, 2019Date of Patent: July 7, 2020Assignee: FUJITSU LIMITEDInventor: Fujio Kurokawa
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Publication number: 20200042025Abstract: A power supply circuit includes a converter configured to convert an input voltage into an output voltage, a memory, and a processor coupled to the memory and the processor configured to control the converter so as to make the output voltage constant, control the converter so as to cause the output voltage to transit to a transient state, based on an instruction, measure a first time until the output voltage reaches a first voltage, based on the instruction, and generate a warning signal when the first time reaches a second time.Type: ApplicationFiled: July 10, 2019Publication date: February 6, 2020Applicant: FUJITSU LIMITEDInventor: Fujio Kurokawa
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Publication number: 20200044570Abstract: A power apparatus includes a power circuit configured to receive an input voltage and generate an output voltage, a memory, and a processor coupled to the memory and the processor configured to calculate an integral value of an error between the output voltage and a target voltage of the power circuit, calculate a duty ratio based on the integral value, the power circuit being controlled according to the calculated duty ratio so that the output voltage becomes the target voltage, calculate a slope of the integral value with respect to an output current of the power circuit, and generate a first warning signal when the calculated slope exceeds a first warning threshold in a case where the calculated slope is different from an initial value.Type: ApplicationFiled: July 18, 2019Publication date: February 6, 2020Applicant: FUJITSU LIMITEDInventor: Fujio Kurokawa
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Patent number: 9595891Abstract: Provided are a control device and a control device for a power conversion circuit, said control device having a first control circuit that compensates for detection delays in an analog-to-digital conversion circuit of a second control circuit that compensates for response delays of the integral element and the derivative element of the first control circuit. A first control circuit (212), which has a first analog-to-digital converter at the input stage thereof, generates an amount of time, which is a first control amount, on the basis of sampling information for a controlled object, and applies an operation initiation signal to a second control circuit (222) when a period of time, lasting for the first control amount, has passed from a prescribed reference time.Type: GrantFiled: March 29, 2013Date of Patent: March 14, 2017Assignee: NAGASAKI UNIVERSITYInventors: Fujio Kurokawa, Tsukasa Takahashi, Kouta Bansyou, Tooru Tanaka
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Patent number: 9543836Abstract: In a control device of a power converter circuit repeating accumulation of energy to an inductor and release of energy from the inductor at each turn on/turn off timing of a switch, a zero cross detecting circuit detects a time when a current flowing through the inductor becomes zero by inputting a voltage between both terminals of the inductor directly without any resistance for detecting the inductor current. There is no electricity loss caused by the resistance for detecting the inductor current and critical mode control of the power converter circuit is precisely carried out.Type: GrantFiled: May 31, 2013Date of Patent: January 10, 2017Assignees: NAGASAKI UNIVERSITY, PANASONIC CORPORATIONInventors: Fujio Kurokawa, Masahito Ohnishi
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Patent number: 9389627Abstract: By adding a suppression amount for suppressing an overshoot or undershoot that attenuates with time during an overshoot or undershoot period, the overshoot or undershoot can be suppressed within a short time and the output can be made close to a normal value. When an output has overshot, an overshoot suppression amount including a time-dependent attenuation suppression amount is added to an output feedback control amount, the time-dependent attenuation suppression amount being defined in a period during which the output overshoots. Alternatively, when the output has undershot, an undershoot suppression amount including a time-dependent attenuation suppression amount is added to the output feedback control amount, the time-dependent attenuation suppression amount being defined in a period during which the output undershoots.Type: GrantFiled: January 31, 2011Date of Patent: July 12, 2016Assignees: NAGASAKI UNIVERSITY, NATIONAL UNIVERSITY CORPORATION, MITSUBISHI ELECTRIC CORPORATIONInventors: Fujio Kurokawa, Hiroyuki Osuga
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Patent number: 9350264Abstract: It provides the effective power conversion control technique which it can control which it made use of a characteristic (nature) of each A/D converter in. It comprises the third control part including the third operating circuit it inputs signal from third A/D converter inputting the detecting signal which is different from the detecting signal which is the same as the detecting signal or the detecting signal and above third A/D converter, and to generate the third operating signal, and the above actuating management circuit manages the actuating of an above first control part and the second above control part and the third above control part.Type: GrantFiled: March 31, 2011Date of Patent: May 24, 2016Assignee: NAGASAKI UNIVERSITY, NATIONAL UNIVERSITY CORPORATIONInventor: Fujio Kurokawa
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Patent number: 9331574Abstract: A highly accurate control is achieved in such a way that a timing value is generated from a differential control amount calculation result and a filter calculation result at iteration intervals not exceeding the iteration intervals of the filter calculation and then the timing set value of a driving signal generation circuit is updated by this timing value. A device for controlling a power conversion circuit comprises an AD conversion circuit (22), a driving timing value generation circuit (23), and a driving signal generation circuit (24). The driving timing value generation circuit (23) includes a control amount calculation circuit (231) and a digital-digital addition circuit (232). The digital-digital addition circuit (232) generates a driving timing value for a switch of a power conversion circuit. The driving signal generation circuit (24) receives the driving timing value and generates a driving signal for the switch (11) of the power conversion circuit (1).Type: GrantFiled: February 28, 2009Date of Patent: May 3, 2016Assignee: NAGASAKI UNIVERSITY, NATIONAL UNIVERSITY CORPORATIONInventor: Fujio Kurokawa
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Patent number: 9329214Abstract: The frequency decision device determines frequency of the measured rectangular signal by simple and easy means. The frequency decision device inputs the measured rectangular signal that frequency (or period) changes dynamically. It generates a rectangular reference signal of predetermined on width ? synchronizing to the edge based on a positive going edge of this measured rectangle signal. And it watches the order of measured rectangle signal and falling edges of the rectangular reference signal. When this sequential order reversed, it detects that length of the ON time of ON time of the measured rectangle signal and the measured rectangular signal reversed.Type: GrantFiled: September 30, 2010Date of Patent: May 3, 2016Assignee: NAGASAKI UNIVERSITY, NATIONAL UNIVERSITY CORPORATIONInventor: Fujio Kurokawa
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Patent number: 9297842Abstract: Disclosed are a device and a method for comparing a detected frequency signal (first frequency signal) and a second frequency signal which is obtained by delaying the detected frequency, to determine whether the frequency transitioned to a predetermined area on high frequency side or reached a predetermined value on the upward direction side. The frequency detection device (1) comprises: a delayed signal output circuit (11) that outputs a second frequency signal (F2) obtained by delaying the first frequency signal (F1), which has a frequency that changes over time, by a set period (?i); and a determination circuit (12), which inputs the first frequency signal (F1) and the second frequency signal (F2), determines whether or not the cycle of the first frequency signal (F1) is included in the cycle of the second frequency signal (F2) and/or whether or not the cycle of the second frequency signal (F2) is included in the cycle of the first frequency signal (F1), and outputs a determination signal.Type: GrantFiled: November 30, 2008Date of Patent: March 29, 2016Assignee: NAGASAKI UNIVERSITY, NATIONAL UNIVERSITY CORPORATIONInventor: Fujio Kurokawa
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Patent number: 9281742Abstract: In DC/DC converter circuit, the peak value of the reactor current is found based on output voltage and an input voltage, thereby, the operation with the predetermined electric current mode is thereby enabled. The AC/DC converter circuit is run with a predetermined current mode, the power factor improvement is accomplished. The first control part 211 inputs a detected value of output voltage Eo, and a turn-off timing predicted value of switch Tr of the DC/DC converter 1 is calculated. The first control part 211 sends the calculation result to the switch drive signal generate part 213. The second control part 212 inputs the detected value of the output voltage and the input voltage, and it receives the turn-off timing predicted value from the first control part 211.Type: GrantFiled: September 18, 2012Date of Patent: March 8, 2016Assignees: NAGASAKI UNIVERSITY, PANASONIC CORPORATIONInventors: Fujio Kurokawa, Masahito Ohnishi
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Publication number: 20150162849Abstract: Provided are a control device and a control device for a power conversion circuit, said control device having a first control circuit that compensates for detection delays in an analog-to-digital conversion circuit of a second control circuit that compensates for response delays of the integral element and the derivative element of the first control circuit. A first control circuit (212), which has a first analog-to-digital converter at the input stage thereof, generates an amount of time, which is a first control amount, on the basis of sampling information for a controlled object, and applies an operation initiation signal to a second control circuit (222) when a period of time, lasting for the first control amount, has passed from a prescribed reference time.Type: ApplicationFiled: March 29, 2013Publication date: June 11, 2015Inventors: Fujio Kurokawa, Tsukasa Takahashi, Kouta Bansyou, Tooru Tanaka
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Publication number: 20150155778Abstract: The control device 1A includes an on-time information generation circuit 11, a zero cross detecting circuit 12 and a PWM signal generation circuit 13. The on-time information generation circuit 11 inputs at least a power converter circuit information including an output voltage value of a power converter circuit 2, and generates the on-time information about a switch 212. The zero cross detecting circuit 12 detects a time when a inductor current becomes zero by inputting a voltage between both terminals of the inductor 214, and generates a zero cross detection signal when the inductor current became zero. The PWM signal generation circuit 13 inputs the on-time information and the zero cross detection signal, and generates a turn on signal and a turnoff signal. The zero cross detecting circuit 12 has an edge detecting circuit.Type: ApplicationFiled: May 31, 2013Publication date: June 4, 2015Inventors: Fujio Kurokawa, Masahito Ohnishi
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Publication number: 20150003129Abstract: In DC/DC converter circuit, the peak value of the reactor current is found based on output voltage and an input voltage, thereby, the operation with the predetermined electric current mode is thereby enabled. The AC/DC converter circuit is run with a predetermined current mode, the power factor improvement is accomplished. The first control part 211 inputs a detected value of output voltage Eo, and a turn-off timing predicted value of switch Tr of the DC/DC converter 1 is calculated. The first control part 211 sends the calculation result to the switch drive signal generate part 213. The second control part 212 inputs the detected value of the output voltage and the input voltage, and it receives the turn-off timing predicted value from the first control part 211.Type: ApplicationFiled: September 18, 2012Publication date: January 1, 2015Inventors: Fujio Kurokawa, Masahito Ohnishi
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Patent number: 8598858Abstract: The first sampling measurement value compares whether to exceed a prescribed threshold and judges the control part at the sampling time. The control part compares whether the first sampling measurement value exceeds a prescribed threshold. When the actual measurement value doesn't exceed a prescribed threshold, the control part predict the first sampling value at the next sampling time. [1] When the first sampling the predicting value doesn't exceed the threshold value, the status of the switch is maintained, [2] When the first sampling the predicting value exceeds the threshold value, the time when the movement of the switch should be changed is calculated and the status of the switch is changed at time concerned.Type: GrantFiled: April 30, 2008Date of Patent: December 3, 2013Assignee: Nagasaki University, National University CorporationInventor: Fujio Kurokawa
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Patent number: 8493046Abstract: Disclosed herein is a control device for a DC/DC converter, in which FB control and FF control are combined to estimate an output voltage of a nonlinear dynamic system while guaranteeing stability. The control device includes a FB controller which generates a first time value for switch-off timing as the amount of feedback control, a machine learning controller which generates a second time value for switch-off timing as the amount of FF control, and a difference time calculator which obtains a difference between the first time value and the second time value and transmits a difference signal to the drive circuit.Type: GrantFiled: September 30, 2010Date of Patent: July 23, 2013Assignees: Nagasaki University, National University Corporation, Mitsubishi Electric CorporationInventors: Fujio Kurokawa, Hiroyuki Osuga
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Patent number: 8451631Abstract: To detect a peak time of an exciting current of a transformer, a primary current corresponding to the peak time, or a variation time of the primary voltage, and to switch a switch after expiration of a predetermined period from the peak time, after the peak time occurs. A control apparatus 1 is applied to a power conversion circuit 2 which includes a switch circuit 23 including one switch or a plurality of switches and a transformer 21. The control apparatus includes: an output voltage detector 11 detecting a value of an output voltage of the power conversion circuit; an exciting current peak time generator 12 detecting a peak time of an exciting current of the transformer; a timing generator 13 generating a switching timing of the one switch or the plurality of switches. The timing generator 13 generates the switching timing of the one switch or the plurality of switches on the basis of the output voltage and the peak time.Type: GrantFiled: October 31, 2008Date of Patent: May 28, 2013Assignee: Nagasaki UniversityInventor: Fujio Kurokawa
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Publication number: 20130106383Abstract: By adding a suppression amount for suppressing an overshoot or undershoot that attenuates with time during an overshoot or undershoot period, the overshoot or undershoot can be suppressed within a short time and the output can be made close to a normal value. When an output has overshot, an overshoot suppression amount including a time-dependent attenuation suppression amount is added to an output feedback control amount, the time-dependent attenuation suppression amount being defined in a period during which the output overshoots. Alternatively, when the output has undershot, an undershoot suppression amount including a time-dependent attenuation suppression amount is added to the output feedback control amount, the time-dependent attenuation suppression amount being defined in a period during which the output undershoots.Type: ApplicationFiled: January 31, 2011Publication date: May 2, 2013Applicants: NAGASAKI UNIVERSITY, NATIONAL UNIVERSITY CORPORATION, MITSUBISHI ELECTRIC CORPORATIONInventors: Fujio Kurokawa, Hiroyuki Osuga
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Publication number: 20130094259Abstract: It provides the effective power conversion control technique which it can control which it made use of a characteristic (nature) of each A/D converter in. It comprises the third control part including the third operating circuit it inputs signal from third A/D converter inputting the detecting signal which is different from the detecting signal which is the same as the detecting signal or the detecting signal and above third A/D converter, and to generate the third operating signal, and the above actuating management circuit manages the actuating of an above first control part and the second above control part and the third above control part.Type: ApplicationFiled: March 31, 2011Publication date: April 18, 2013Applicant: Nagasaki University, National University CorporationInventor: Fujio Kurokawa