Patents by Inventor Toshikazu Fujiyoshi

Toshikazu Fujiyoshi 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).

  • Patent number: 8873259
    Abstract: A DC-DC converter includes a regeneration snubber circuit. The snubber circuit is connected in parallel with the secondary diode circuit and includes a series circuit of a discharge blocking diode, a snubber capacitor, and a switching element for regeneration connected in parallel with the discharge blocking diode. The DC-DC converter further includes a control unit which turns the switching element for regeneration on a predetermined time period after the timing of turning the primary side switching element off. The predetermined time period is set to approximately the time period during which the charge, accumulated in the snubber capacitor due to reverse recovery time when one of the secondary diodes has been turned off, discharges.
    Type: Grant
    Filed: February 25, 2009
    Date of Patent: October 28, 2014
    Assignee: Sansha Electric Manufacturing Co., Ltd.
    Inventors: Toshikazu Fujiyoshi, Hajime Katsushima, Kenji Morimoto, Satoshi Yamamura
  • Patent number: 8400799
    Abstract: This inverter circuit includes first and second switching elements and an output transformer which is provided with a first primary winding connected in series between said first and second switching elements, and also with a secondary winding for obtaining an output voltage. The inverter circuit is further provided with a first voltage supply, a second voltage supply, and a control unit. The first voltage supply applies voltage to said first switching element via said first primary winding. And the second voltage supply applies voltage to said second switching element via said second primary winding. The control unit turns said first switching element and said second switching element alternatingly ON and OFF. This inverter circuit also includes first and second regeneration snubber circuits for regenerating the charge charged into snubber capacitors.
    Type: Grant
    Filed: February 6, 2009
    Date of Patent: March 19, 2013
    Assignee: Sansha Electric Manufacturing Co., Ltd.
    Inventors: Toshikazu Fujiyoshi, Hajime Katsushima, Kenji Morimoto, Satoshi Yamamura
  • Patent number: 8363432
    Abstract: This DC-DC converter circuit includes: first and second switching elements (S1, S2); an output transformer (T) that includes a first primary winding (P1) connected in series between the positive electrode sides of the first and second switching elements (S1, S2), a second primary winding (P2) connected in series between their negative electrode sides, a secondary winding (S) for obtaining an output voltage, and tertiary windings (n3, n4); a first voltage source (C1), connected between a first connection point at which the first primary winding (P1) is connected to the second switching element (S2) and the first switching element (S1), that applies a voltage to the first switching element via the first primary winding; a second voltage source (C2) connected to locations symmetric with those of the first voltage source (C1); and a control unit (CT) that turns the first and second switching elements (S1, S2) alternatingly ON and OFF, and first and second regeneration snubber circuits (SN1, SN2) for regenerating
    Type: Grant
    Filed: December 16, 2009
    Date of Patent: January 29, 2013
    Assignee: Sansha Electric Manufacturing Co., Ltd.
    Inventors: Hajime Katsushima, Toshikazu Fujiyoshi, Kenji Morimoto, Hajime Yamamoto, Satoshi Yamamura
  • Publication number: 20120243263
    Abstract: This DC-DC converter circuit includes: first and second switching elements (S1, S2); an output transformer (T) that includes a first primary winding (P1) connected in series between the positive electrode sides of the first and second switching elements (S1, S2), a second primary winding (P2) connected in series between their negative electrode sides, a secondary winding (S) for obtaining an output voltage, and tertiary windings (n3, n4); a first voltage source (C1), connected between a first connection point at which the first primary winding (P1) is connected to the second switching element (S2) and the first switching element (S1), that applies a voltage to the first switching element via the first primary winding; a second voltage source (C2) connected to locations symmetric with those of the first voltage source (C1); and a control unit (CT) that turns the first and second switching elements (S1, S2) alternatingly ON and OFF, and first and second regeneration snubber circuits (SN1, SN2) for regenerating
    Type: Application
    Filed: December 16, 2009
    Publication date: September 27, 2012
    Inventors: Hajime Katsushima, Toshikazu Fujiyoshi, Kenji Morimoto, Hajime Yamamoto, Satoshi Yamamura
  • Patent number: 8107265
    Abstract: This inverter circuit includes two switching elements which are turned alternately ON and OFF, and a first primary winding connected in series between these switching elements, and also includes an output transformer having a secondary winding for obtaining an output voltage. This inverter circuit also includes a first voltage source and a second voltage source. The first voltage source applies a voltage to the first switching element via the first primary winding. And the second voltage source applies a voltage to the second switching element via the second primary winding. This inverter circuit also includes a regeneration snubber circuit for regenerating charge accumulated in a snubber capacitor. The regeneration snubber circuit includes a regeneration circuit including a voltage boost section which converts the primary side voltage of the output transformer to a predetermined voltage, which it outputs.
    Type: Grant
    Filed: January 30, 2009
    Date of Patent: January 31, 2012
    Assignee: Sansha Electric Manufacturing Co., Ltd.
    Inventors: Toshikazu Fujiyoshi, Hajime Katsushima, Kenji Morimoto, Satoshi Yamamura
  • Patent number: 8094470
    Abstract: This current balanced push-pull type inverter circuit includes first and second switching elements, and an output transformer which includes a first primary winding and a second primary winding connected in series between said first and second switching elements, and also includes a secondary winding for obtaining an output voltage. This inverter circuit also includes a first voltage supply capacitor, a second voltage supply capacitor, and a control unit. A first snubber circuit, in which a first free wheel diode and first and second snubber capacitors are connected in series, is connected in inverse parallel to the first switching element. A first discharge resistor is connected between the first snubber capacitor and a first power supply capacitor, and a second discharge resistor is connected between the second snubber capacitor and a third power supply capacitor. And a second snubber circuit and discharge resistors are connected to the second switching element as well, in a similar manner.
    Type: Grant
    Filed: March 10, 2009
    Date of Patent: January 10, 2012
    Assignee: Sansha Electric Manufacturing Co., Ltd.
    Inventors: Toshikazu Fujiyoshi, Hajime Katsushima, Kenji Morimoto, Satoshi Yamamura
  • Patent number: 8094469
    Abstract: This inverter circuit includes first and second switching elements and an output transformer which has a first primary winding connected in series between the first switching element and the second switching element and a second primary winding for obtaining an output voltage. The inverter circuit also includes a first voltage source, a second voltage source, and a control unit. The first voltage source is connected between a first connection point at which the first primary winding is connected to the second switching element, and the first switching element, and applies a voltage to the first switching element via the first primary winding. And the second voltage source is connected between a second connection point at which the first primary winding is connected to the first switching element, and the second switching element, and applies a voltage to the second switching element via the first primary winding.
    Type: Grant
    Filed: November 27, 2008
    Date of Patent: January 10, 2012
    Assignee: Sansha Electric Manufacturing Co., Ltd.
    Inventors: Toshikazu Fujiyoshi, Hajime Katsushima, Kenji Morimoto, Satoshi Yamamura
  • Publication number: 20110280048
    Abstract: This DC-DC converter circuit includes a switching circuit which switches a DC power supply with a primary side switching element, a transformer to a primary side winding whereof the output of the switching circuit is applied and which outputs a voltage which has been changed by a predetermined voltage change ratio to a secondary side winding, and secondary diodes for current adjustment connected to the secondary side winding of the transformer. Moreover, it includes a regeneration snubber circuit connected in parallel with the secondary diode circuit and including a series circuit of a discharge blocking diode and a snubber capacitor and a switching element for regeneration connected in parallel with the discharge blocking diode, a filter circuit connected between rectification outputs of the secondary diode circuit, and a control unit which turns the switching element for regeneration ON a predetermined time period after the timing of turning the primary side switching element OFF.
    Type: Application
    Filed: February 25, 2009
    Publication date: November 17, 2011
    Inventors: Toshikazu Fujiyoshi, Hajime Katsushima, Kenji Morimoto, Satoshi Yamamura
  • Publication number: 20110280054
    Abstract: This inverter circuit includes first and second switching elements and an output transformer which has a first primary winding connected in series between the first switching element and the second switching element and a second primary winding for obtaining an output voltage. The inverter circuit also includes a first voltage source, a second voltage source, and a control unit. The first voltage source is connected between a first connection point at which the first primary winding is connected to the second switching element, and the first switching element, and applies a voltage to the first switching element via the first primary winding. And the second voltage source is connected between a second connection point at which the first primary winding is connected to the first switching element, and the second switching element, and applies a voltage to the second switching element via the first primary winding.
    Type: Application
    Filed: November 27, 2008
    Publication date: November 17, 2011
    Inventors: Toshikazu Fujiyoshi, Hajime Katsushima, Kenji Morimoto, Satoshi Yamamura
  • Publication number: 20110216557
    Abstract: This inverter circuit includes first and second switching elements and an output transformer which is provided with a first primary winding connected in series between said first and second switching elements, and also with a secondary winding for obtaining an output voltage. The inverter circuit is further provided with a first voltage supply, a second voltage supply, and a control unit. The first voltage supply applies voltage to said first switching element via said first primary winding. And the second voltage supply applies voltage to said second switching element via said second primary winding. The control unit turns said first switching element and said second switching element alternatingly ON and OFF. This inverter circuit also includes first and second regeneration snubber circuits for regenerating the charge charged into snubber capacitors.
    Type: Application
    Filed: February 6, 2009
    Publication date: September 8, 2011
    Inventors: Toshikazu Fujiyoshi, Hajime Katsushima, Kenji Morimoto, Satoshi Yamamura
  • Publication number: 20110058395
    Abstract: This current balanced push-pull type inverter circuit includes first and second switching elements, and an output transformer which includes a first primary winding and a second primary winding connected in series between said first and second switching elements, and also includes a secondary winding for obtaining an output voltage. This inverter circuit also includes a first voltage supply capacitor, a second voltage supply capacitor, and a control unit. A first snubber circuit, in which a first free wheel diode and first and second snubber capacitors are connected in series, is connected in inverse parallel to the first switching element. A first discharge resistor is connected between the first snubber capacitor and a first power supply capacitor, and a second discharge resistor is connected between the second snubber capacitor and a third power supply capacitor. And a second snubber circuit and discharge resistors are connected to the second switching element as well, in a similar manner.
    Type: Application
    Filed: March 10, 2009
    Publication date: March 10, 2011
    Inventors: Toshikazu Fujiyoshi, Hajime Katsushima, Kenji Morimoto, Satoshi Yamamura
  • Publication number: 20110049989
    Abstract: This inverter circuit includes two switching elements which are turned alternately ON and OFF, and a first primary winding connected in series between these switching elements, and also includes an output transformer having a secondary winding for obtaining an output voltage. This inverter circuit also includes a first voltage source and a second voltage source. The first voltage source applies a voltage to the first switching element via the first primary winding. And the second voltage source applies a voltage to the second switching element via the second primary winding. This inverter circuit also includes a regeneration snubber circuit for regenerating charge accumulated in a snubber capacitor. The regeneration snubber circuit includes a regeneration circuit including a voltage boost section which converts the primary side voltage of the output transformer to a predetermined voltage, which it outputs.
    Type: Application
    Filed: January 30, 2009
    Publication date: March 3, 2011
    Inventors: Toshikazu Fujiyoshi, Hajime Katsushima, Kenji Morimoto, Satoshi Yamamura
  • Patent number: 7075032
    Abstract: An input-side rectifier (4), a smoothing capacitor (6), an inverter (8), a transformer (10) and an output-side rectifier (12) operate together to convert an AC voltage supplied from an AC power supply to a DC voltage. The DC voltage is coupled through a DC-to-AC converter (16) to a workpiece (18) and a torch (20). An auxiliary voltage supply (28) supplies the workpiece (18) and the torch (20) with a negative voltage for a short time following the transition of the AC voltage supplied to the workpiece (18) and the torch (20) from positive to negative. The negative voltage has a negative peak value larger than the negative peak value of the AC voltage supplied to the workpiece (18) and the torch (20), and rapidly changes from the negative peak value.
    Type: Grant
    Filed: November 21, 2003
    Date of Patent: July 11, 2006
    Assignee: Sansha Electric Manufacturing Company, Limited
    Inventors: Kunio Karino, Toshikazu Fujiyoshi, Kenzo Danjo, Hideo Ishii
  • Patent number: 6914788
    Abstract: Capacitors (4, 6) are connected in series across a DC power supply (2). IGBTs (8, 10) are connected in series across the DC power supply (2), too. The IGBTs (8, 10) are rendered conductive alternately. A transformer (12) is connected between the junction of the capacitors (4, 6) and the junction of the IGBTs (8, 10). Snubber capacitors (32, 38) are connected in parallel with the IGBTs (8, 10), respectively. Diodes (34, 40) are connected in series with respective ones of the snubber capacitors (32, 38) in such a manner that said snubber capacitors (32, 38) can be charged when the IGBTs (8, 10) are rendered nonconductive. A secondary winding (54SA) of a transformer (54) is connected between the DC power supply (2) and the junction of the snubber capacitor (32) and the diode (34), and converts a secondary voltage of the transformer (12) and returns the converted voltage to the DC power supply (2) when the IGBT (8) is conductive.
    Type: Grant
    Filed: March 2, 2004
    Date of Patent: July 5, 2005
    Assignee: Sansha Electric Manufacturing Company, Limite
    Inventors: Toshikazu Fujiyoshi, Kenji Morimoto, Satoshi Hamada
  • Publication number: 20050109749
    Abstract: An input-side rectifier (4), a smoothing capacitor (6), an inverter (8), a transformer (10) and an output-side rectifier (12) operate together to convert an AC voltage supplied from an AC power supply to a DC voltage. The DC voltage is coupled through a DC-to-AC converter (16) to a workpiece (18) and a torch (20). An auxiliary voltage supply (28) supplies the workpiece (18) and the torch (20) with a negative voltage for a short time following the transition of the AC voltage supplied to the workpiece (18) and the torch (20) from positive to negative. The negative voltage has a negative peak value larger than the negative peak value of the AC voltage supplied to the workpiece (18) and the torch (20), and rapidly changes from the negative peak value.
    Type: Application
    Filed: November 21, 2003
    Publication date: May 26, 2005
    Inventors: Kunio Karino, Toshikazu Fujiyoshi, Kenzo Danjo, Hideo Ishii
  • Publication number: 20040174725
    Abstract: Capacitors (4, 6) are connected in series across a DC power supply (2). IGBTs (8, 10) are connected in series across the DC power supply (2), too. The IGBTs (8, 10) are rendered conductive alternately. A transformer (12) is connected between the junction of the capacitors (4, 6) and the junction of the IGBTs (8, 10). Snubber capacitors (32, 38) are connected in parallel with the IGBTs (8, 10), respectively. Diodes (34, 40) are connected in series with respective ones of the snubber capacitors (32, 38) in such a manner that said snubber capacitors (32, 38) can be charged when the IGBTs (8, 10) are rendered nonconductive. A secondary winding (54SA) of a transformer (54) is connected between the DC power supply (2) and the junction of the snubber capacitor (32) and the diode (34), and converts a secondary voltage of the transformer (12) and returns the converted voltage to the DC power supply (2) when the IGBT (8) is conductive.
    Type: Application
    Filed: March 2, 2004
    Publication date: September 9, 2004
    Inventors: Toshikazu Fujiyoshi, Kenji Morimoto, Satoshi Hamada
  • Patent number: 6774757
    Abstract: Metallic coils sheets (34, 36, 38) are planar and include center windows (34a, 36a, 38a). Slits (34b, 36b, 38b) extend outward through the respective sheets from the windows. Connection terminals (34c, 34d; 36c, 36d; 38c, 38d) are provided on the sheets at locations facing across the respective slits. The metallic coil sheets are stacked, and adjacent ones of the stacked metallic coil sheets are electrically connected by means of the connection terminals. A core (60, 62) is disposed in the windows of the stacked metallic coil sheets. The metallic coil sheets are individually covered with an insulating coating.
    Type: Grant
    Filed: May 27, 2003
    Date of Patent: August 10, 2004
    Assignee: Sansha Electric Manufacturing Company, Limited
    Inventors: Toshikazu Fujiyoshi, Masao Katooka, Tetsuro Ikeda, Kenji Morimoto, Hideo Ishii
  • Publication number: 20030222751
    Abstract: Metallic coils sheets (34, 36, 38) are planar and include center windows (34a, 36a, 38a). Slits (34b, 36b, 38b) extend outward through the respective sheets from the windows. Connection terminals (34c, 34d; 36c, 36d; 38c, 38d) are provided on the sheets at locations facing across the respective slits. The metallic coil sheets are stacked, and adjacent ones of the stacked metallic coil sheets are electrically connected by means of the connection terminals. A core (60, 62) is disposed in the windows of the stacked metallic coil sheets. The metallic coil sheets are individually covered with an insulating coating.
    Type: Application
    Filed: May 27, 2003
    Publication date: December 4, 2003
    Inventors: Toshikazu Fujiyoshi, Masao Katooka, Tetsuro Ikeda, Kenji Morimoto, Hideo Ishii
  • Patent number: 6636140
    Abstract: A high-frequency large current handling transformer includes a stack of plural metal planar coil members with a window formed in a center portion of each of the planar coil member. A slit extends outward from the window in each planar coil member. First and second terminals are provided for each planar coil member at locations on opposite sides of the slit. An insulating sheet having a window formed in its center portion is disposed between adjacent ones of the planar coil members. Some of the planar coil members are connected in series to provide a higher-voltage side coil, and the remaining planar coil members are connected in parallel to provide a lower-voltage side coil. An 8-shaped high-frequency core is operatively combined with the coils.
    Type: Grant
    Filed: December 6, 2001
    Date of Patent: October 21, 2003
    Assignee: Sansha Electric Manufacturing Company, Limited
    Inventors: Toshikazu Fujiyoshi, Masao Katooka, Tetsuro Ikeda, Kenji Morimoto, Hideo Ishii
  • Patent number: 6433664
    Abstract: A conductor is wound around a magnetic core to form a plurality of conductor turns. The conductor turns are spaced from one another by a substantially equal spacing d. An insulating layer is disposed between the conductor turns and the magnetic core. An insulating member is wound around the magnetic core in such a manner as to be located in the spaces between and in contact with adjacent ones of the conductor turns.
    Type: Grant
    Filed: September 6, 2000
    Date of Patent: August 13, 2002
    Assignee: Sansha Electric Manufacturing Company, Limited
    Inventors: Hideo Ishii, Toshikazu Fujiyoshi, Masao Katooka