Patents by Inventor Keiji Kawanaka
Keiji Kawanaka 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: 9591696Abstract: An object is to provide an induction heating method having a high power factor in which when thermal processing is performed through a plurality of heating coils receiving the supply of the current to generate mutual induction. In an induction heating method using an induction heating device that includes self-resonant circuits which feeds currents of equal frequency to a plurality of heating coils receiving the supply of the current to generate mutual induction is connected, wherein adjustment or control is performed to carry out an operation such that a first ratio of a reactance component of a mutual induction impedance to a resistance component of the mutual induction impedance between the adjacent self-resonant circuits and a second ratio of a reactance component of a self-impedance to a resistance component of the self-impedance in the self-resonant circuit are made equal to each other.Type: GrantFiled: January 23, 2013Date of Patent: March 7, 2017Assignee: Mitsui Engineering & Shipbuilding Co., Ltd.Inventors: Naoki Uchida, Nobutaka Matsunaka, Keiji Kawanaka, Kazuyoshi Fujita, Takahiro Ao
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Publication number: 20150108118Abstract: [Object] An object is to provide an induction heating method having a high power factor in which when thermal processing is performed through a plurality of heating coils receiving the supply of the current to generate mutual induction, it is possible to easily and rapidly perform synchronization control on a coil current and in which when the current is varied, even if the speed of control on the current value is increased, this little affects an inverter phase angle. [Solving means] In an induction heating method using an induction heating device that heats an item to be heated and includes a plurality of self-resonant circuits to which a resonant high-frequency power supply feeding currents of equal frequency to a plurality of heating coils receiving the supply of the current to generate mutual induction is connected, the phases of impedances within a system are made to coincide with each other to minimize the phases.Type: ApplicationFiled: January 23, 2013Publication date: April 23, 2015Inventors: Naoki Uchida, Nobutaka Matsunaka, Keiji Kawanaka, Kazuyoshi Fujita, Takahiro Ao
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Patent number: 8890042Abstract: The present invention includes: a plurality of induction heating coils (11, 12, 13) which are disposed adjacently; capacitors (21, 22, 23) each of which is connected in series thereto; a plurality of inverters (30, 35, 31) each of which applies a high frequency voltage converted from a DC voltage to each series resonant circuit of the induction heating coil and the capacitor; and a control circuit (50) which operates the plurality of the inverters with a same frequency and current synchronization, controls so that a phase difference becomes minimal at a specific inverter, which supplies the maximum power to the plurality of the induction heating coils, between the high frequency voltage generated therefrom, and a resonant current flowing the series resonant circuit, and set a DC power supply voltage Vdc applied to the plurality of the inverters so that the output voltages (Vinv) become greater than mutual induction voltages (Vm).Type: GrantFiled: November 2, 2011Date of Patent: November 18, 2014Assignee: Mitsui Engineering & Shipbuilding Co., Ltd.Inventors: Naoki Uchida, Keiji Kawanaka, Takahiro Ao
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Publication number: 20140008356Abstract: The present invention includes: a plurality of induction heating coils (11, 12, 13) which are disposed adjacently; capacitors (21, 22, 23) each of which is connected in series thereto; a plurality of inverters (30, 35, 31) each of which applies a high frequency voltage converted from a DC voltage to each series resonant circuit of the induction heating coil and the capacitor; and a control circuit (50) which operates the plurality of the inverters with a same frequency and current synchronization, controls so that a phase difference becomes minimal at a specific inverter, which supplies the maximum power to the plurality of the induction heating coils, between the high frequency voltage generated therefrom, and a resonant current flowing the series resonant circuit, and set a DC power supply voltage Vdc applied to the plurality of the inverters so that the output voltages (Vinv) become greater than mutual induction voltages (Vm).Type: ApplicationFiled: November 2, 2011Publication date: January 9, 2014Applicant: MITSUI ENGINEERING & SHIPBUILDING CO., LTD.Inventors: Naoki Uchida, Keiji Kawanaka, Takahiro Ao
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Patent number: 7432481Abstract: It is an object of the present invention to prevent temperature decrease in a border portion of each of heating coils and to enable to eliminate an influence given by the change in a load state. In order to attain this object, an induction heating unit according to the present invention is provided with control units respectively corresponding to a plurality of heating units. A phase detector of the control unit obtains a phase difference between an output current (heating coil current) of an inverter detected by a current transformer reference signal outputted by a reference signal generating section, and inputs it to a drive control section. The drive control section adjusts an output timing (phase) of a gate pulse to be given to the inverter so as to make a phase of the heating coil current of the inverter coincide with a phase of the reference signal outputted by the reference signal generating section.Type: GrantFiled: June 26, 2006Date of Patent: October 7, 2008Assignee: Mitsui Engineering & Shipbuilding Co., Ltd.Inventors: Naoki Uchida, Keiji Kawanaka, Hideyuki Nanba, Kazuhiro Ozaki
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Patent number: 7230216Abstract: It is an object of the present invention to prevent temperature decrease in a border portion of each of heating coils and to enable to eliminate an influence given by the change in a load state. In order to attain this object, an induction heating unit according to the present invention is provided with control units respectively corresponding to a plurality of heating units. A phase detector of the control unit obtains a phase difference between an output current (heating coil current) of an inverter detected by a current transformer reference signal outputted by a reference signal generating section, and inputs it to a drive control section. The drive control section adjusts an output timing (phase) of a gate pulse to be given to the inverter so as to make a phase of the heating coil current of the inverter coincide with a phase of the reference signal outputted by the reference signal generating section.Type: GrantFiled: June 26, 2006Date of Patent: June 12, 2007Assignee: Mitsui Engineering & Shipbuilding Co., Ltd.Inventors: Naoki Uchida, Keiji Kawanaka, Hideyuki Nanba, Kazuhiro Ozaki
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Publication number: 20070125771Abstract: It is an object of the present invention to prevent temperature decrease in a border portion of each of heating coils and to enable to eliminate an influence given by the change in a load state. In order to attain this object, an induction heating unit according to the present invention is provided with control units respectively corresponding to a plurality of heating units. A phase detector of the control unit obtains a phase difference between an output current (heating coil current) of an inverter detected by a current transformer reference signal outputted by a reference signal generating section, and inputs it to a drive control section. The drive control section adjusts an output timing (phase) of a gate pulse to be given to the inverter so as to make a phase of the heating coil current of the inverter coincide with a phase of the reference signal outputted by the reference signal generating section.Type: ApplicationFiled: June 26, 2006Publication date: June 7, 2007Applicant: Mitsui Engineering & Shipbuilding Co., Ltd.Inventors: Naoki Uchida, Keiji Kawanaka, Hideyuki Nanba, Kazuhiro Ozaki
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Patent number: 7202451Abstract: It is an object of the present invention to prevent temperature decrease in a border portion of each of heating coils and to enable to eliminate an influence given by the change in a load state. In order to attain this object, an induction heating unit 400 according to the present invention is provided with control units 420 (420a to 420d) respectively corresponding to a plurality of heating units 310 (310a to 310d). A phase detector 424d of the control unit 420d obtains a phase difference between an output current (heating coil current IL4) of an inverter 314d detected by a current transformer 160d and a reference signal outputted by a reference signal generating section 426, and inputs it to a drive control section 422d. The drive control section 422d adjusts an output timing (phase) of a gate pulse to be given to the inverter 314d so as to make a phase of the heating coil current IL4 of the inverter 314d coincide with a phase of the reference signal outputted by the reference signal generating section 426.Type: GrantFiled: June 26, 2002Date of Patent: April 10, 2007Assignee: Mitsui Engineering & Shipbuilding Co., Ltd.Inventors: Naoki Uchida, Keiji Kawanaka, Hideyuki Nanba, Kazuhiro Ozaki
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Publication number: 20060237449Abstract: It is an object of the present invention to prevent temperature decrease in a border portion of each of heating coils and to enable to eliminate an influence given by the change in a load state. In order to attain this object, an induction heating unit according to the present invention is provided with control units respectively corresponding to a plurality of heating units. A phase detector of the control unit obtains a phase difference between an output current (heating coil current) of an inverter detected by a current transformer reference signal outputted by a reference signal generating section, and inputs it to a drive control section. The drive control section adjusts an output timing (phase) of a gate pulse to be given to the inverter so as to make a phase of the heating coil current of the inverter coincide with a phase of the reference signal outputted by the reference signal generating section.Type: ApplicationFiled: June 26, 2006Publication date: October 26, 2006Applicant: Mitsui Engineering & Shipbuilding Co., Ltd.Inventors: Naoki Uchida, Keiji Kawanaka, Hideyuki Nanba, Kazuhiro Ozaki
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Publication number: 20060237450Abstract: It is an object of the present invention to prevent temperature decrease in a border portion of each of heating coils and to enable to eliminate an influence given by the change in a load state. In order to attain this object, an induction heating unit according to the present invention is provided with control units respectively corresponding to a plurality of heating units. A phase detector of the control unit obtains a phase difference between an output current (heating coil current) of an inverter detected by a current transformer reference signal outputted by a reference signal generating section, and inputs it to a drive control section. The drive control section adjusts an output timing (phase) of a gate pulse to be given to the inverter so as to make a phase of the heating coil current of the inverter coincide with a phase of the reference signal outputted by the reference signal generating section.Type: ApplicationFiled: June 26, 2006Publication date: October 26, 2006Applicant: Mitsui Engineering & Shipbuilding Co., Ltd.Inventors: Naoki Uchida, Keiji Kawanaka, Hideyuki Nanba, Kazuhiro Ozaki
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Publication number: 20050199614Abstract: It is an object of the present invention to prevent temperature decrease in a border portion of each of heating coils and to enable to eliminate an influence given by the change in a load state. In order to attain this object, an induction heating unit 400 according to the present invention is provided with control units 420 (420a to 420d) respectively corresponding to a plurality of heating units 310 (310a to 310d). A phase detector 424d of the control unit 420d obtains a phase difference between an output current (heating coil current IL4) of an inverter 314d detected by a current transformer 160d and a reference signal outputted by a reference signal generating section 426, and inputs it to a drive control section 422d. The drive control section 422d adjusts an output timing (phase) of a gate pulse to be given to the inverter 314d so as to make a phase of the heating coil current IL4 of the inverter 314d coincide with a phase of the reference signal outputted by the reference signal generating section 426.Type: ApplicationFiled: June 26, 2002Publication date: September 15, 2005Applicant: MITSUI ENGINEERING & SHIPBUILDINGInventors: Naoki Uchida, Keiji Kawanaka, Hideyuki Nanba, Kazuhiro Ozaki