Patents by Inventor Ching-Shan Leu

Ching-Shan Leu 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: 9473045
    Abstract: A soft-switching and low input current ripple power inversion circuit, in which the inversion circuit is connected in parallel to an input DC voltage source and includes a top cell, a bottom cell and at least one transformer, in which the top cell and the bottom cell have its individual impedance adjusting unit of which the impedance can easily be adjusted to obtain the required equivalent resonant inductance or capacitance. Thus, the semiconducting switches therein can be soft-switched alternately to reduce the switching loss. Moreover, the inversion circuit can be modified by adding at least one middle cell inserted between the top cell and the bottom cell to reduce the voltage stress on the semiconductor switch. Consequently, low voltage rating semiconductor switch accompanied with lower RDS(on), conduction losses can be reduced to improve the converter efficiency.
    Type: Grant
    Filed: April 21, 2015
    Date of Patent: October 18, 2016
    Assignee: NATIONAL TAIWAN UNIVERSITY OF SCIENCE AND TECHNOLOGY
    Inventor: Ching-Shan Leu
  • Publication number: 20150303788
    Abstract: A soft-switching and low input current ripple power inversion circuit, in which the inversion circuit is connected in parallel to an input DC voltage source and includes a top cell, a bottom cell and at least one transformer, in which the top cell and the bottom cell have its individual impedance adjusting unit of which the impedance can easily be adjusted to obtain the required equivalent resonant inductance or capacitance. Thus, the semiconducting switches therein can be soft-switched alternately to reduce the switching loss. Moreover, the inversion circuit can be modified by adding at least one middle cell inserted between the top cell and the bottom cell to reduce the voltage stress on the semiconductor switch. Consequently, low voltage rating semiconductor switch accompanied with lower RDS(on), conduction losses can be reduced to improve the converter efficiency.
    Type: Application
    Filed: April 21, 2015
    Publication date: October 22, 2015
    Inventor: Ching-Shan LEU
  • Patent number: 8665616
    Abstract: The present invention relates to a near zero current-ripple inversion circuit including top and bottom cells, a transformer (T1) comprising primary windings (P1, P2) and a secondary winding (S1), and at least one middle cell connected in series between the top and bottom cells. The top cell comprises two capacitors (C1, C2) and a switch (Q1) each connecting to the middle cell, and an inductor (Lr1) and the primary winding (P1) connected in series between the capacitor (C1) and switch (Q1), wherein the switch (Q1) is connected to the capacitors (C1, C2) respectively. The bottom cell comprises a capacitor (C3) and a switch (Q2) each connecting to the middle cell, and an inductor (Lr2) and the primary winding (P2) connected in series between the capacitor (C3) and switch (Q2), wherein the primary winding (P2) is connected to the middle cell, and the capacitor (C3) and switch (Q2) are connected.
    Type: Grant
    Filed: May 16, 2012
    Date of Patent: March 4, 2014
    Assignee: National Taiwan University of Science and Technology
    Inventors: Ching-Shan Leu, Pin-Yu Huang
  • Publication number: 20130308353
    Abstract: The present invention relates to a near zero current-ripple inversion circuit including top and bottom cells, a transformer (T1) comprising primary windings (P1, P2) and a secondary winding (S1), and at least one middle cell connected in series between the top and bottom cells. The top cell comprises two capacitors (C1, C2) and a switch (Q1) each connecting to the middle cell, and an inductor (Lr1) and the primary winding (P1) connected in series between the capacitor (C1) and switch (Q1), wherein the switch (Q1) is connected to the capacitors (C1, C2) respectively. The bottom cell comprises a capacitor (C3) and a switch (Q2) each connecting to the middle cell, and an inductor (Lr2) and the primary winding (P2) connected in series between the capacitor (C3) and switch (Q2), wherein the primary winding (P2) is connected to the middle cell, and the capacitor (C3) and switch (Q2) are connected.
    Type: Application
    Filed: May 16, 2012
    Publication date: November 21, 2013
    Applicant: National Taiwan University of Science and Technology
    Inventors: Ching-Shan LEU, Pin-Yu Huang
  • Patent number: 8259469
    Abstract: A circuit used to convert DC input to AC output comprises a transformer and three series sub-circuits. The first series sub-circuit is connected in parallel with the DC input and comprises first and second capacitors connected in series. The secondary series sub-circuit is connected in parallel with the DC input and comprises a first primary winding of the transformer, a clamping capacitor and a second primary winding of the transformer sequentially connected in series. The third series sub-circuit connected in parallel with said clamping capacitor and comprises first and second switches connected in series. The center nodes of the first and third series sub-circuits are connected together. Thus, while a secondary winding of the transformer provides AC voltage, the circuit is able to effectively reduce current ripple and decrease voltage stress on semiconductor switch with minimum component count. Similar topologies may be used for rectification instead of inversion.
    Type: Grant
    Filed: August 30, 2010
    Date of Patent: September 4, 2012
    Assignee: National Taiwan University of Science and Technology
    Inventors: Ching-Shan Leu, Pin-Yu Huang
  • Patent number: 8199540
    Abstract: A high voltage gain power converter includes: a main switch element; an assistant switch element; a first inductive element, a first switch element, and a first capacitive element; and a second inductive element, a second switch element, and a second capacitive element. The first inductive element is connected between an input node and first switch element. The first capacitive element, connected between the first switch element and ground, provides a first boost output voltage. The second inductive element is connected between the main switch element and first capacitive element. The second switch element is connected to a common node of the second inductive element and main switch element. The second capacitive element, connecting the second switch element to a first node, provides a second boost output voltage. The assistant switch element is connected between the first inductive element and common node of the second inductive element and main switch element.
    Type: Grant
    Filed: January 6, 2010
    Date of Patent: June 12, 2012
    Assignee: National Taiwan University of Science and Technology
    Inventors: Ching-Shan Leu, Jing-Cheng Lin, Shun-Yuan Wu
  • Publication number: 20120051108
    Abstract: A circuit used to convert DC input to AC output comprises a transformer and three series sub-circuits. The first series sub-circuit is connected in parallel with the DC input and comprises first and second capacitors connected in series. The secondary series sub-circuit is connected in parallel with the DC input and comprises a first primary winding of the transformer, a clamping capacitor and a second primary winding of the transformer sequentially connected in series. The third series sub-circuit connected in parallel with said clamping capacitor and comprises first and second switches connected in series. The center nodes of the first and third series sub-circuits are connected together. Thus, while a secondary winding of the transformer provides AC voltage, the circuit is able to effectively reduce current ripple and decrease voltage stress on semiconductor switch with minimum component count. Similar topologies may be used for rectification instead of inversion.
    Type: Application
    Filed: August 30, 2010
    Publication date: March 1, 2012
    Applicant: National Taiwan University of Science and Technology
    Inventors: Ching-Shan LEU, Pin-Yu HUANG
  • Publication number: 20110199802
    Abstract: This invention discloses apparatus and methods for increasing the duty cycle of the single ended power converters surpass 50 percent limitation by adding active switch-capacitor network to the primary circuit and several inversion circuits can be realized to convert a DC input to an AC output. The circuits comprise two series circuits, at least one clamp clamping capacitor, and at least one transformer. The first series circuit includes one active switch paralleled with a diode, one capacitor and at least one transformer primary. The second series circuit includes at least one active switch and at least one transformer primary. At least one clamp clamping capacitor couples the first and the second series circuits, and is attached to each series circuit at a node between the respective transformer primary winding.
    Type: Application
    Filed: April 25, 2011
    Publication date: August 18, 2011
    Applicant: National Taiwan University of Science and Technology
    Inventor: Ching-Shan Leu
  • Publication number: 20110163599
    Abstract: A high voltage gain power converter includes: a main switch element; an assistant switch element; a first inductive element, a first switch element, and a first capacitive element; and a second inductive element, a second switch element, and a second capacitive element. The first inductive element is connected between an input node and first switch element. The first capacitive element, connected between the first switch element and ground, provides a first boost output voltage. The second inductive element is connected between the main switch element and first capacitive element. The second switch element is connected to a common node of the second inductive element and main switch element. The second capacitive element, connecting the second switch element to a first node, provides a second boost output voltage. The assistant switch element is connected between the first inductive element and common node of the second inductive element and main switch element.
    Type: Application
    Filed: January 6, 2010
    Publication date: July 7, 2011
    Applicant: National Taiwan University of Science and Technology
    Inventors: Ching-Shan Leu, Jing-Cheng Lin, Shun-Yuan Wu
  • Patent number: 7957161
    Abstract: A power converter capable of improving converter's efficiency and achieving zero-voltage-switching is provided, in which a first series circuit is connected in parallel with a direct current (DC) power supply and has a first inductor, a first primary winding, first and second switching elements connected in series. A second series circuit is connected in parallel with the DC power supply and has third and fourth switching elements, a first capacitor, a second primary winding and a second inductor connected in series. A second capacitor is connected between a first node between the first primary winding and the first switching element in the first series circuit and a second node between the fourth switching element and the second primary winding in the second series circuit. A third node between the first and second switching elements is connected to a fourth node within the second series circuit.
    Type: Grant
    Filed: March 3, 2009
    Date of Patent: June 7, 2011
    Assignee: National Taiwan University of Science and Technology
    Inventor: Ching-Shan Leu
  • Publication number: 20100226154
    Abstract: A power converter capable of improving converter's efficiency and achieving zero-voltage-switching is provided, in which a first series circuit is connected in parallel with a direct current (DC) power supply and has a first inductor, a first primary winding, first and second switching elements connected in series. A second series circuit is connected in parallel with the DC power supply and has third and fourth switching elements, a first capacitor, a second primary winding and a second inductor connected in series. A second capacitor is connected between a first node between the first primary winding and the first switching element in the first series circuit and a second node between the fourth switching element and the second primary winding in the second series circuit. A third node between the first and second switching elements is connected to a fourth node within the second series circuit.
    Type: Application
    Filed: March 3, 2009
    Publication date: September 9, 2010
    Applicant: NATIONAL TAIWAN UNIVERSITY OF SCIENCE & TECHNOLOGY
    Inventor: Ching-Shan Leu
  • Publication number: 20090257254
    Abstract: Several inversion circuits used to convert a DC input to an AC output comprise two series circuits, at least one clamp capacitor, and at least one transformer. Each of the series circuits is in parallel with the DC input. The first series circuit includes one switch network and at least one transformer primary. The second series circuit includes one voltage-clamp network and at least one transformer primary. At least one clamp capacitor couples the first and the second series circuits, and is attached to each series circuit at a node between the respective transformer primary winding. The voltage-clamp network may be implemented with two of the three sub-circuits connected in series: a diode, a resister-capacitor-diode, and a MOSFET-capacitor.
    Type: Application
    Filed: April 15, 2008
    Publication date: October 15, 2009
    Applicant: National Taiwan University of Science and Technology
    Inventor: Ching-Shan Leu
  • Patent number: 7515439
    Abstract: A circuit used to convert a DC input to an AC output comprises a pair of series circuits, one or two capacitors, and one transformer. Each of the series circuits is in parallel with the DC input and comprises a pair of series-connected switches and at least one transformer primary. Each capacitor couples the two series circuits, and is attached to each series circuit at a node between the respective transformer primary and switch. The center nodes between two series-connected switches are connected together. At least one secondary on the transformer provides the AC output. Optionally, multiple transformers may be utilized. Similar topologies may be used for rectification instead of inversion.
    Type: Grant
    Filed: June 18, 2007
    Date of Patent: April 7, 2009
    Assignee: National Taiwan University of Science & Technology
    Inventor: Ching-Shan Leu
  • Publication number: 20080025051
    Abstract: A circuit used to convert a DC input to an AC output comprises a pair of series circuits, one or two capacitors, and one transformer. Each of the series circuits is in parallel with the DC input and comprises a pair of series-connected switches and at least one transformer primary. Each capacitor couples the two series circuits, and is attached to each series circuit at a node between the respective transformer primary and switch. The center nodes between two series-connected switches are connected together. At least one secondary on the transformer provides the AC output. Optionally, multiple transformers may be utilized. Similar topologies may be used for rectification instead of inversion.
    Type: Application
    Filed: June 18, 2007
    Publication date: January 31, 2008
    Inventor: Ching-Shan Leu
  • Patent number: 5901054
    Abstract: A PWM controlling circuit includes a signal generator and two PWM controllers. The signal generator comprises an oscillator, a plurality of inverters, and two RC delay networks. The oscillator and the inverters are composed of elementary elements, respectively, such as diodes, resistors, inverters and capacitors. The PWM controlling circuit in accordance with the present invention can be implemented with low cost, and the duty cycles thereof are not limited to 50%.
    Type: Grant
    Filed: December 18, 1997
    Date of Patent: May 4, 1999
    Assignee: Chun-Shan Institute of Science and Technology
    Inventors: Ching-Shan Leu, Jeang Hwang, Wueichan Liu
  • Patent number: 5640318
    Abstract: A forward converter for a switching power supply includes a direct current voltage source having a positive electrode and a negative electrode, a transformer having four identical primary windings each having a first end and a second end and a secondary winding connected to a load, the first end of a first primary winding and the second end of a fourth primary winding being connected to the positive electrode of the voltage source, the first end of a third primary winding and the second end of a second primary winding are connected to the negative electrode of the voltage source, two series-connected power switches connected between the second end of the first primary winding and the first end of the second primary winding and defining a common point between the power switches for simultaneously turning on and off in response to a control signal, a first diode connected between the common point of the power switches and the first end of the fourth primary winding, a second diode connected between the second e
    Type: Grant
    Filed: July 1, 1996
    Date of Patent: June 17, 1997
    Inventor: Ching-shan Leu
  • Patent number: 5523936
    Abstract: A built-in input filter forward converter performs to shape an input current to a non-pulsating fashion. Shaping action is obtained by placing two cross-coupled capacitors to a plurality of splitting windings of a power transformer such that the input current will not be interrupted. The cross-coupled capacitors also operate as a lossless snubber by allowing the leakage inductance energy to be stored and recovered during normal operation. Thus significant improvements of reducing harmonic of the input current, input current ripple, and increasing the converter's efficiency are achieved.
    Type: Grant
    Filed: July 25, 1994
    Date of Patent: June 4, 1996
    Assignee: Chun-Shan Institute of Science and Technology
    Inventors: Ching-Shan Leu, Jiun-Bin Hwang