Patents by Inventor Tiefu Zhao

Tiefu Zhao 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: 10890932
    Abstract: An apparatus for a load tap changer includes a first primary winding electrically connected to a first contact, the first contact configured to connect to one of a plurality of taps in a load tap changer; a second contact, the second contact configured to connect to one of the plurality of taps in the load tap changer; a magnetic core; and a control circuit including: a secondary winding configured to magnetically couple to the first primary winding and the magnetic core; and an electrical network electrically connected to the secondary winding, the electrical network being configured to prevent magnetic saturation of the magnetic core during switching of the first or second contact.
    Type: Grant
    Filed: August 5, 2019
    Date of Patent: January 12, 2021
    Assignee: Eaton Intelligent Power Limited
    Inventors: Jonathan Michael Schaar, Tiefu Zhao
  • Publication number: 20200057461
    Abstract: An apparatus for a load tap changer includes a first primary winding electrically connected to a first contact, the first contact configured to connect to one of a plurality of taps in a load tap changer; a second contact, the second contact configured to connect to one of the plurality of taps in the load tap changer; a magnetic core; and a control circuit including: a secondary winding configured to magnetically couple to the first primary winding and the magnetic core; and an electrical network electrically connected to the secondary winding, the electrical network being configured to prevent magnetic saturation of the magnetic core during switching of the first or second contact.
    Type: Application
    Filed: August 5, 2019
    Publication date: February 20, 2020
    Inventors: Jonathan Michael Schaar, Tiefu Zhao
  • Patent number: 10141787
    Abstract: The present invention provides a receiving circuit for magnetic coupling resonant wireless power transmission comprising: a resonant circuit, which comprises a resonant coil and a resonant capacitor; a rectifying circuit, the input of which is electrically connected to the two terminals of the resonant capacitor; a storage capacitor, the two terminals of which are electrically connected to the output of rectifying circuit; and a DC-DC converter, the input of which is electrically connected to the two terminals of the storage capacitor and the output of which is electrically connected to a rechargeable battery. The receiving circuit for magnetic coupling resonant wireless power transmission of the present invention can save energy and has high charge efficiency.
    Type: Grant
    Filed: March 3, 2015
    Date of Patent: November 27, 2018
    Assignee: Eaton Capital Unlimited Company
    Inventors: Gerald Zheng, Jack Gu, Bruce Wu, Tiefu Zhao, Jun Xu, Birger Pahl, Yahan Hua
  • Patent number: 10116230
    Abstract: A method of operating an AC to DC converter circuit can be provided by changing a configuration of a DC output filter circuit to reshape a current waveform in a rectifier circuit, included in the AC to DC converter circuit, based on an operating efficiency of the AC to DC converter circuit. Related circuits and articles of manufacture are also disclosed.
    Type: Grant
    Filed: December 30, 2013
    Date of Patent: October 30, 2018
    Assignee: Eaton Capital Unlimited Company
    Inventors: Tangshun Wu, Jr., Jun Xu, Tiefu Zhao, Birger Pahl
  • Patent number: 10038324
    Abstract: A wireless power transfer circuit can include an input port that can be configured to couple to a power source, an ac excitation circuit having a port coupled to the input port, a resonant circuit coupled to the ac excitation circuit, and a controller circuit that can be configured to operate the ac excitation circuit. The wireless power transfer circuit can operate to inductively transfer power from the resonant circuit and the controller circuit can be configured to change an operating frequency of the ac excitation circuit and change a configuration of the resonant circuit responsive a change in indicated efficiency of the wireless power transfer.
    Type: Grant
    Filed: January 6, 2015
    Date of Patent: July 31, 2018
    Assignee: Eaton Intelligent Power Limited
    Inventors: Prasanna Nirantare, Tiefu Zhao, Birger Pahl, Milind Kothekar, Yahan Hua
  • Patent number: 10020802
    Abstract: An integrated circuit is provided with an MCU, which is configured to generate a PWM control signal that is free of switching pattern information therein. A current-estimating gate driver is provided, which is responsive to the PWM signal. This gate driver is configured to drive first and second gate terminals of first and second parallel switching devices (within a hybrid switch) with gate signals that establish a second switching pattern within the hybrid switch. These gate driving operations are performed in response to measuring a first voltage associated with a terminal of the hybrid switch when being driven by gate signals that establish a first switching pattern within the hybrid switch that is different from the second switching pattern. The duty cycles of the gate signals associated with the second switching pattern are unequal and the duty cycles of the gate signals associated with the first switching pattern are unequal.
    Type: Grant
    Filed: June 27, 2017
    Date of Patent: July 10, 2018
    Assignee: Eaton Intelligent Power Limited
    Inventors: Tiefu Zhao, Jiangbiao He, Yakov Lvovich Familiant, Mengbin Ben Yang
  • Publication number: 20170344039
    Abstract: A voltage regulator includes a tap changer coupled to a voltage source terminal and a voltage load terminal, The voltage regulator also includes a first switch and a first current transformer coupled in series between the voltage load terminal and a first movable contact of the tap changer. The voltage regulator further includes a second switch and a second transformer coupled in series between the voltage load terminal and a second movable contact of the tap changer, A first silicon controlled rectifier and a second silicon controlled rectifier are controlled by a first control circuit and a second control circuit, respectively. The first control circuit and the second control circuit each include a rectifier, a gating switch, and a positive voltage detector.
    Type: Application
    Filed: May 27, 2016
    Publication date: November 30, 2017
    Applicant: COOPER TECHNOLOGIES COMPANY
    Inventors: Frederick Alan Stich, Tiefu Zhao
  • Publication number: 20170294911
    Abstract: An integrated circuit is provided with an MCU, which is configured to generate a PWM control signal that is free of switching pattern information therein. A current-estimating gate driver is provided, which is responsive to the PWM signal. This gate driver is configured to drive first and second gate terminals of first and second parallel switching devices (within a hybrid switch) with gate signals that establish a second switching pattern within the hybrid switch. These gate driving operations are performed in response to measuring a first voltage associated with a terminal of the hybrid switch when being driven by gate signals that establish a first switching pattern within the hybrid switch that is different from the second switching pattern. The duty cycles of the gate signals associated with the second switching pattern are unequal and the duty cycles of the gate signals associated with the first switching pattern are unequal.
    Type: Application
    Filed: June 27, 2017
    Publication date: October 12, 2017
    Inventors: Tiefu Zhao, Jiangbiao He, Yakov Lvovich Familiant, Mengbin Ben Yang
  • Patent number: 9722581
    Abstract: An integrated circuit is provided with an MCU, which is configured to generate a PWM control signal that is free of switching pattern information therein. A current-estimating gate driver is provided, which is responsive to the PWM signal. This gate driver is configured to drive first and second gate terminals of first and second parallel switching devices (within a hybrid switch) with gate signals that establish a second switching pattern within the hybrid switch. These gate driving operations are performed in response to measuring a first voltage associated with a terminal of the hybrid switch when being driven by gate signals that establish a first switching pattern within the hybrid switch that is different from the second switching pattern. The duty cycles of the gate signals associated with the second switching pattern are unequal and the duty cycles of the gate signals associated with the first switching pattern are unequal.
    Type: Grant
    Filed: December 19, 2014
    Date of Patent: August 1, 2017
    Assignee: Eaton Corporation
    Inventors: Tiefu Zhao, Jiangbiao He, Yakov Lvovich Familiant, Mengbin Ben Yang
  • Publication number: 20170070082
    Abstract: The present invention provides a receiving circuit for magnetic coupling resonant wireless power transmission comprising: a resonant circuit, which comprises a resonant coil and a resonant capacitor; a rectifying circuit, the input of which is electrically connected to the two terminals of the resonant capacitor; a storage capacitor, the two terminals of which are electrically connected to the output of rectifying circuit; and a DC-DC converter, the input of which is electrically connected to the two terminals of the storage capacitor and the output of which is electrically connected to a rechargeable battery. The receiving circuit for magnetic coupling resonant wireless power transmission of the present invention can save energy and has high charge efficiency.
    Type: Application
    Filed: March 3, 2015
    Publication date: March 9, 2017
    Applicant: COOPER INDUSTRIES HOLDINGS
    Inventors: GERALD ZHENG, JACK GU, BRUCE WU, TIEFU ZHAO, JUN XU, BIRGER PAHL, YAHAN HUA
  • Patent number: 9397657
    Abstract: An integrated circuit includes a hybrid switch having first and second switching devices of different type therein. A control circuit is provided, which is configured to drive the first and second devices with respective first and second control signals having first and second unequal duty cycles, respectively, when the first and second devices are supporting a forward current in a first current range. The control circuit is further configured to drive the first and second devices with respective third and fourth control signals having third and fourth unequal duty cycles, respectively, when the first and second devices are supporting a forward current in a second current range outside the first current range. The first duty cycle may be greater than the second duty cycle and the third duty cycle may be less than the fourth duty cycle.
    Type: Grant
    Filed: December 19, 2014
    Date of Patent: July 19, 2016
    Assignee: Eaton Corporation
    Inventors: Tiefu Zhao, Jiangbiao He, Vijay Bhavaraju, Mengbin Ben Yang
  • Publication number: 20160197485
    Abstract: A wireless power transfer circuit can include an input port that can be configured to couple to a power source, an ac excitation circuit having a port coupled to the input port, a resonant circuit coupled to the ac excitation circuit, and a controller circuit that can be configured to operate the ac excitation circuit. The wireless power transfer circuit can operate to inductively transfer power from the resonant circuit and the controller circuit can be configured to change an operating frequency of the ac excitation circuit and change a configuration of the resonant circuit responsive a change in indicated efficiency of the wireless power transfer.
    Type: Application
    Filed: January 6, 2015
    Publication date: July 7, 2016
    Inventors: Prasanna Nirantare, Tiefu Zhao, Birger Pahl, Milind Kothekar, Yahan Hua
  • Publication number: 20160191046
    Abstract: An integrated circuit includes a hybrid switch having first and second switching devices of different type therein. A control circuit is provided, which is configured to drive the first and second devices with respective first and second control signals having first and second unequal duty cycles, respectively, when the first and second devices are supporting a forward current in a first current range. The control circuit is further configured to drive the first and second devices with respective third and fourth control signals having third and fourth unequal duty cycles, respectively, when the first and second devices are supporting a forward current in a second current range outside the first current range. The first duty cycle may be greater than the second duty cycle and the third duty cycle may be less than the fourth duty cycle.
    Type: Application
    Filed: December 19, 2014
    Publication date: June 30, 2016
    Inventors: Tiefu Zhao, Jiangbiao He, Vijay Bhavaraju, Mengbin Ben Yang
  • Publication number: 20160191021
    Abstract: An integrated circuit is provided with an MCU, which is configured to generate a PWM control signal that is free of switching pattern information therein. A current-estimating gate driver is provided, which is responsive to the PWM signal. This gate driver is configured to drive first and second gate terminals of first and second parallel switching devices (within a hybrid switch) with gate signals that establish a second switching pattern within the hybrid switch. These gate driving operations are performed in response to measuring a first voltage associated with a terminal of the hybrid switch when being driven by gate signals that establish a first switching pattern within the hybrid switch that is different from the second switching pattern. The duty cycles of the gate signals associated with the second switching pattern are unequal and the duty cycles of the gate signals associated with the first switching pattern are unequal.
    Type: Application
    Filed: December 19, 2014
    Publication date: June 30, 2016
    Inventors: Tiefu Zhao, Jiangbiao He, Yakov Lvovich Familiant, Mengbin Ben Yang
  • Patent number: 9287418
    Abstract: A system and method for selectively connecting photovoltaic (PV) arrays of a PV power system in series and parallel arrangements is disclosed. A DC-to-AC power inverter in the PV power system is electrically coupled to a plurality of PV arrays to receive a DC output therefrom and invert the DC output to an AC output, with the DC-to-AC power inverter including a DC link that receives the DC output from the plurality of PV arrays. A contactor arrangement is positioned between the plurality of PV arrays and the DC-to-AC power inverter, with the contactor arrangement including a plurality of contactors that are switchable between an on state and an off state to selectively connect the plurality of PV arrays to the DC-to-AC power inverter in a specified arrangement, so as to control a level of DC voltage received by the DC-to-AC power inverter from the plurality of PV arrays.
    Type: Grant
    Filed: June 29, 2012
    Date of Patent: March 15, 2016
    Assignee: Eaton Corporation
    Inventors: Prasanna S. Nirantare, Vijay Bhavaraju, Tiefu Zhao, Jun Xu, Christopher Scott Thompson
  • Patent number: 9123466
    Abstract: Wireless power transfer systems include at least one foil-type transmitter/receiver coil with a plurality of turns, which is configured to reduce eddy current losses therein when energized to conduct an alternating current that supports inductive power transfer including coil-to-coil power electrical transfer, inductive heating, etc. The plurality of turns includes at least an outermost turn with a first arcuate-shaped corner having a concave inner surface, which faces an immediately adjacent one of the plurality of turns. The immediately adjacent one of the plurality of turns may also have a second arcuate-shaped corner with a concave inner surface facing an innermost one of the plurality of turns. The first arcuate-shaped corner may have a non-uniform radius of curvature and/or an innermost one of the plurality of turns may have an arcuate-shaped corner, which is a mirror image of the first arcuate-shaped corner when the coil is view in transverse cross-section.
    Type: Grant
    Filed: November 11, 2013
    Date of Patent: September 1, 2015
    Assignee: Eaton Corporation
    Inventors: Qingjie Zheng, Yilei Gu, Tangshun Wu, Tiefu Zhao, Jun Xu, Birger Pahl, Yahan Hua
  • Publication number: 20150188446
    Abstract: A method of operating an AC to DC converter circuit can be provided by changing a configuration of a DC output filter circuit to reshape a current waveform in a rectifier circuit, included in the AC to DC converter circuit, based on an operating efficiency of the AC to DC converter circuit. Related circuits and articles of manufacture are also disclosed.
    Type: Application
    Filed: December 30, 2013
    Publication date: July 2, 2015
    Inventors: Tangshun Wu, Jun Xu, Tiefu Zhao, Birger Pahl
  • Publication number: 20150130583
    Abstract: Wireless power transfer systems include at least one foil-type transmitter/receiver coil with a plurality of turns, which is configured to reduce eddy current losses therein when energized to conduct an alternating current that supports inductive power transfer including coil-to-coil power electrical transfer, inductive heating, etc. The plurality of turns includes at least an outermost turn with a first arcuate-shaped corner having a concave inner surface, which faces an immediately adjacent one of the plurality of turns. The immediately adjacent one of the plurality of turns may also have a second arcuate-shaped corner with a concave inner surface facing an innermost one of the plurality of turns. The first arcuate-shaped corner may have a non-uniform radius of curvature and/or an innermost one of the plurality of turns may have an arcuate-shaped corner, which is a mirror image of the first arcuate-shaped corner when the coil is view in transverse cross-section.
    Type: Application
    Filed: November 11, 2013
    Publication date: May 14, 2015
    Applicant: Eaton Corporation
    Inventors: Qingjie Zheng, Yilei Gu, Tangshun Wu, Tiefu Zhao, Jun Xu, Birger Pahl, Yahan Hua
  • Patent number: 8638531
    Abstract: A hybrid DC contactor includes contacts that provide a first current path between a DC power source and a load, an electromagnetic coil to position the contacts, a semiconductor switch in parallel with contacts that, when turned on, provides a second parallel current path that diverts current away from the contacts when the main contacts are being opened in either direction. A controller is provided to terminate power to the electromagnetic coil to open the contacts, detect an arc voltage across the contacts as the contacts open, provide a gate signal to the semiconductor switch to pulse the switch on for a pre-determined period of time to route current to the semiconductor switch, measure a current through the contacts and, if current is present through the contacts, then provide another gate signal to the semiconductor switch to pulse the switch on again so as to route current thereto.
    Type: Grant
    Filed: December 14, 2011
    Date of Patent: January 28, 2014
    Assignee: Eaton Corporation
    Inventors: Vijay Bhavaraju, Tiefu Zhao, Peter J. Theisen
  • Publication number: 20140001864
    Abstract: A system and method for selectively connecting photovoltaic (PV) arrays of a PV power system in series and parallel arrangements is disclosed. A DC-to-AC power inverter in the PV power system is electrically coupled to a plurality of PV arrays to receive a DC output therefrom and invert the DC output to an AC output, with the DC-to-AC power inverter including a DC link that receives the DC output from the plurality of PV arrays. A contactor arrangement is positioned between the plurality of PV arrays and the DC-to-AC power inverter, with the contactor arrangement including a plurality of contactors that are switchable between an on state and an off state to selectively connect the plurality of PV arrays to the DC-to-AC power inverter in a specified arrangement, so as to control a level of DC voltage received by the DC-to-AC power inverter from the plurality of PV arrays.
    Type: Application
    Filed: June 29, 2012
    Publication date: January 2, 2014
    Inventors: Prasanna S. Nirantare, Vijay Bhavaraju, Tiefu Zhao, Jun Xu, Christopher Scott Thompson