Patents by Inventor Lihua Hu

Lihua Hu 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: 10992129
    Abstract: A power distribution system includes power converter systems electrically connected to a distribution bus which defines a point of common coupling. Each power converter system includes a power converter with semiconductor switching devices controlled using a pulse width modulation strategy with a switching frequency. A controller for each power converter system applies a spectrum analysis process to the respective power converter system that uses measured or derived zero sequence currents associated with the respective power converter system to determine the location of a ground fault within the power distribution system. Each controller applies a switching frequency process where the switching frequency of the power converter of at least one of the power converter systems is different from the switching frequency of the power converter of at least another one of the power converter systems during at least part of the time that the spectrum analysis process is applied.
    Type: Grant
    Filed: August 22, 2016
    Date of Patent: April 27, 2021
    Assignee: GE ENERGY POWER CONVERSION TECHNOLOGY LTD.
    Inventors: Lihua Hu, Teng Long, Martin Samuel Butcher, Allan David Crane
  • Publication number: 20190317809
    Abstract: The present disclosure provides an implementation method and apparatus of timer, the method includes: determining a counting period of a hardware timer according to expiration time of a timer node expires first in a timer linked list; and when the counting period of the hardware timer is expired, traversing through the timer node in the timer linked list and updating the counting period of the hardware timer. The present disclosure provides a technical solution that can effectively reduce system power consumption and processor resource occupancy.
    Type: Application
    Filed: June 26, 2019
    Publication date: October 17, 2019
    Inventors: MING ZHU, MINGLIANG WANG, GUOCHAO YIN, LIHUA HU
  • Publication number: 20180241200
    Abstract: A power distribution system includes power converter systems electrically connected to a distribution bus which defines a point of common coupling. Each power converter system includes a power converter with semiconductor switching devices controlled using a pulse width modulation strategy with a switching frequency. A controller for each power converter system applies a spectrum analysis process to the respective power converter system that uses measured or derived zero sequence currents associated with the respective power converter system to determine the location of a ground fault within the power distribution system. Each controller applies a switching frequency process where the switching frequency of the power converter of at least one of the power converter systems is different from the switching frequency of the power converter of at least another one of the power converter systems during at least part of the time that the spectrum analysis process is applied.
    Type: Application
    Filed: August 22, 2016
    Publication date: August 23, 2018
    Inventors: Lihua HU, Teng LONG, Martin Samuel BUTCHER, Allan David CRANE
  • Patent number: 9825523
    Abstract: A converter control arrangement (18) for regulating the output current of a dc source power converter (16) comprises a current regulator (20) for regulating the output current based on a comparison of an output current value (Iout) of the dc source power converter (16) with a desired target current value (Itgt). When the output voltage value (Vout) of the dc source power converter (16) is within a normal operating voltage range between minimum and maximum voltage values (Vmin, Vmax) defined with respect to a voltage reference value (Vref) of the dc source power converter (16), the converter control arrangement (18) controls the target current value (Itgt) so that it is equal to a desired reference current value (Iref).
    Type: Grant
    Filed: February 29, 2012
    Date of Patent: November 21, 2017
    Assignee: GE Energy Power Conversion Technology LTD
    Inventors: Lihua Hu, Richard Ian Stephens, Martin Samuel Butcher
  • Patent number: 9713884
    Abstract: The present invention relates to a process for producing polyurethane foam moldings where the density of the molding is at most 500 g/L, by mixing the following to give a reaction mixture: a) organic polyisocyanates with b) polyesterols, c) blowing agents, d) cell-opening additives selected from the group consisting of homo- or copolymers based on ethylhexyl acrylate, on polybutadiene, on polyisobutene, and on diorganosilicones, or a mixture of two or more of said antifoams, e) silicone-based cell stabilizers and optionally f) chain extenders and/or crosslinking agents, g) catalysts, and h) other auxiliaries and/or additives, and charging the materials to a mold, and permitting them to complete a reaction to give a polyurethane foam molding. The present invention further relates to polyurethane moldings obtainable by this process, and to the use of said moldings as shoe sole, steering wheel, seat, or armrest.
    Type: Grant
    Filed: November 15, 2011
    Date of Patent: July 25, 2017
    Assignee: BASF SE
    Inventors: Andre Kamm, Dong Liang, ZhiZhong Tang, LiHua Hu
  • Patent number: 9130448
    Abstract: A converter control arrangement for regulating the output voltage of a dc source power converter connecting an ac system to a HVDC system to enable dc electrical power to be supplied from the ac system to the HVDC system comprises a dynamic droop control device including first and second droop controllers in which the droop rate of the second droop controller is greater than the droop rate of the first droop controller. The converter control arrangement comprises a voltage regulator for regulating the output voltage of the dc source power converter by comparing an output voltage value with a target voltage value derived by combining a reference voltage value and a droop voltage value provided by the dynamic droop control device. The reference current value is the desired output current value of the dc source power converter and defines, in combination with the reference voltage value, a target operating point.
    Type: Grant
    Filed: February 7, 2012
    Date of Patent: September 8, 2015
    Assignee: GE ENERGY POWER CONVERSION TECHNOLOGY LTD.
    Inventor: Lihua Hu
  • Publication number: 20130334889
    Abstract: A converter control arrangement (18) for regulating the output current of a dc source power converter (16) comprises a current regulator (20) for regulating the output current based on a comparison of an output current value (Iout) of the dc source power converter (16) with a desired target current value (Itgt). When the output voltage value (Vout) of the dc source power converter (16) is within a normal operating voltage range between minimum and maximum voltage values (Vmin, Vmax) defined with respect to a voltage reference value (Vref) of the dc source power converter (16), the converter control arrangement (18) controls the target current value (Itgt) so that it is equal to a desired reference current value (Iref).
    Type: Application
    Filed: February 29, 2012
    Publication date: December 19, 2013
    Applicant: GE Energy Power Conversion Technology Ltd.
    Inventors: Lihua Hu, Richard Ian Stephens, Martin Samuel Butcher
  • Publication number: 20130314959
    Abstract: A converter control arrangement for regulating the output voltage of a dc source power converter connecting an ac system to a HVDC system to enable dc electrical power to be supplied from the ac system to the HVDC system comprises a dynamic droop control device including first and second droop controllers in which the droop rate of the second droop controller is greater than the droop rate of the first droop controller. The converter control arrangement comprises a voltage regulator for regulating the output voltage of the dc source power converter by comparing an output voltage value with a target voltage value derived by combining a reference voltage value and a droop voltage value provided by the dynamic droop control device. The reference current value is the desired output current value of the dc source power converter and defines, in combination with the reference voltage value, a target operating point.
    Type: Application
    Filed: February 7, 2012
    Publication date: November 28, 2013
    Inventor: Lihua Hu
  • Publication number: 20130249134
    Abstract: The present invention relates to a process for producing polyurethane foam moldings where the density of the molding is at most 500 g/L, by mixing the following to give a reaction mixture: a) organic polyisocyanates with b) polyesterols, c) blowing agents, d) cell-opening additives selected from the group consisting of homo- or copolymers based on ethylhexyl acrylate, on polybutadiene, on polyisobutene, and on diorganosilicones, or a mixture of two or more of said antifoams, e) silicone-based cell stabilizers and optionally f) chain extenders and/or crosslinking agents, g) catalysts, and h) other auxiliaries and/or additives, and charging the materials to a mold, and permitting them to complete a reaction to give a polyurethane foam molding. The present invention further relates to polyurethane moldings obtainable by this process, and to the use of said moldings as shoe sole, steering wheel, seat, or armrest.
    Type: Application
    Filed: November 15, 2011
    Publication date: September 26, 2013
    Applicant: BASF SE
    Inventors: Andre Kamm, Dong Liang, ZhiZhong Tang, LiHua Hu
  • Patent number: 8154260
    Abstract: Within generator systems maintenance of stability in terms of voltage is desirable. Generally, several generators will be arranged in parallel within the generator system with one generator voltage controlled to provide dynamic responsiveness to load switching. With regard to some loads which are generally of an active nature, the capacity of a first generator, which is voltage controlled, may be insufficient to adequately avoid transient voltage instability. By providing an actuator signal from a load to act as a pre-emptive or forward feed to an electrical current controlled generator, that second electrical current generator can be arranged to provide additional or reduced electrical current to avoid system voltage instability.
    Type: Grant
    Filed: March 16, 2009
    Date of Patent: April 10, 2012
    Assignee: Rolls-Royce PLC
    Inventors: Lihua Hu, David R Trainer, Stephen A Long
  • Patent number: 8111496
    Abstract: An earthing arrangement for a DC electrical system (10), the electrical system (10) comprises a plurality of earthing points (24A, 24B, 24C) and each earthing point (24A, 24B, 24C) is directly and permanently connected to earth (26) by a high impedance connection (28A, 28B, 28C). Each earthing point (24A, 24B, 24C) is selectively connectable to earth (26) in electrical parallel with the high impedance connection (28A, 28B, 28C) by a solid connection (30A, 30B, 30C) and a switch (32A, 32B, 32C). In first mode of operation the switch (32A) between the earthing point (24A) and the earth (26) of only one of the plurality of earthing points (24A, 24B, 24C) is closed.
    Type: Grant
    Filed: February 11, 2009
    Date of Patent: February 7, 2012
    Assignee: Rolls-Royce PLC
    Inventors: Stephen A Long, David R Trainer, Lihua Hu, Huw L Edwards
  • Patent number: 7847431
    Abstract: Electrical power generation systems typically comprise an electrical power distribution arrangement in which a number of electrical power generators are coupled in parallel. In such circumstances in order to avoid conflict generally a first electrical power generator is controlled with a voltage controller while second electrical power generators have electrical current controllers. As loads are switched into and out of the electrical distribution system in normal operation the first electrical power generator and its voltage controller can accommodate voltage dynamics and therefore maintain a desired voltage. However, in order to accommodate heavier loads switching, the dynamic operation of the electrical current controller is achieved through utilizing operational voltage margins from a desired voltage as control signals to the electrical current controller.
    Type: Grant
    Filed: March 16, 2009
    Date of Patent: December 7, 2010
    Assignee: Rolls-Royce plc
    Inventors: Lihua Hu, David R Trainer, Stephen A Long
  • Patent number: 7800880
    Abstract: In a DC electrical power system used in an aircraft, an earthing arrangement is provided between electrical power supply rails in the form of a pair of capacitors with a mid electrical voltage earthing point, having an earthing path, in which electrical resistance is provided to limit electrical current flow and therefore allow continued operation despite the earth fault.
    Type: Grant
    Filed: June 6, 2007
    Date of Patent: September 21, 2010
    Assignee: Rolls-Royce plc
    Inventors: Lihua Hu, David R Trainer, Michael P Hirst, Stuart Galloway
  • Publication number: 20100038969
    Abstract: Electrical power generation systems typically comprise an electrical power distribution arrangement in which a number of electrical power generators are coupled in parallel. In such circumstances in order to avoid conflict generally a first electrical power generator is controlled with a voltage controller whilst second electrical power generators have electrical current controllers. As loads are switched into and out of the electrical distribution system in normal operation the first electrical power generator and its voltage controller can accommodate voltage dynamics and therefore maintain a desired voltage. However, in order to accommodate heavier loads switching, the dynamic operation of the electrical current controller is achieved through utilising operational voltage margins from a desired voltage as control signals to the electrical current controller.
    Type: Application
    Filed: March 16, 2009
    Publication date: February 18, 2010
    Applicant: ROLLS-ROYCE PLC
    Inventors: Lihua Hu, David R. Trainer, Stephen A. Long
  • Publication number: 20100033141
    Abstract: Within generator systems maintenance of stability in terms of voltage is desirable. Generally, several generators will be arranged in parallel within the generator system with one generator voltage controlled to provide dynamic responsiveness to load switching. With regard to some loads which are generally of an active nature, the capacity of a first generator, which is voltage controlled, may be insufficient to adequately avoid transient voltage instability. By providing an actuator signal from a load to act as a pre-emptive or forward feed to an electrical current controlled generator, that second electrical current generator can be arranged to provide additional or reduced electrical current to avoid system voltage instability.
    Type: Application
    Filed: March 16, 2009
    Publication date: February 11, 2010
    Applicant: ROLLS-ROYCE PLC
    Inventors: Lihua Hu, David R. Trainer, Stephen A. Long
  • Patent number: 7573243
    Abstract: A generator control arrangement for an electrical power generator, the arrangement comprising a controller arranged to regulate output voltage from a generator to a target value, the controller including a voltage comparator for comparing a presented voltage with a desired output voltage, the presented voltage derived in a transfer comparator by combination of a reference voltage value and an error value between a reference electrical current value and a measured electrical current value subject to a processor gain whereby the processor gain can be specifically set at zero to enable control by voltage or the processor gain can be specifically set at greater than zero to enable control by electrical current.
    Type: Grant
    Filed: February 13, 2007
    Date of Patent: August 11, 2009
    Assignee: Rolls-Royce plc
    Inventors: David R Trainer, Lihua Hu, Michael P Hirst
  • Publication number: 20070287306
    Abstract: In DC electrical power systems used for example in aircraft typically an earthing arrangement is provided between electrical power supply rails in the form of a pair of capacitors with a mid electrical voltage earthing point. In such circumstances in previous arrangements an earth fault will have low impedance to the ground and therefore have excess electrical current flow. By aspects of the present invention electrical resistance is provided in the earthing path to limit electrical current flow and therefore allow continued operation despite the earth fault.
    Type: Application
    Filed: June 6, 2007
    Publication date: December 13, 2007
    Inventors: Lihua Hu, David R. Trainer, Michael P. Hirst, Stuart Galloway
  • Patent number: D864153
    Type: Grant
    Filed: April 25, 2018
    Date of Patent: October 22, 2019
    Inventor: Lihua Hu
  • Patent number: D873789
    Type: Grant
    Filed: July 7, 2017
    Date of Patent: January 28, 2020
    Inventor: Lihua Hu
  • Patent number: D885370
    Type: Grant
    Filed: July 7, 2017
    Date of Patent: May 26, 2020
    Inventor: Lihua Hu