Patents by Inventor Zhihua GU

Zhihua GU 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: 11750097
    Abstract: A switch-mode AC-DC power converter includes a pair of input terminals, a pair of output terminals, and four switches coupled in a bridgeless totem-pole circuit arrangement between the pair of input terminals and the pair of output terminals. A control circuit is coupled to the four switches and configured to, during a cycle of an AC voltage input, turn on the first switch, turn off the second switch, and apply pulse-width modulation (PWM) control signals to the third and fourth switches. The control circuit is also configured to, during a zero crossing of the AC voltage input, supply a PWM control signal to the fourth switch to reduce a rate of voltage change across the second switch at the zero crossing to reduce common mode noise of the power converter.
    Type: Grant
    Filed: November 4, 2021
    Date of Patent: September 5, 2023
    Assignee: Astec International Limited
    Inventors: Zhihua Gu, Siu Chik Wong, Kim Ly Kha
  • Publication number: 20230155486
    Abstract: A multi-phase interleaved PFC converter includes at least six switches coupled in a multi-phase interleaved circuit arrangement, and a control circuit. The control circuit is configured to turn on and turn off a first one of the switches according to a PWM signal to operate the first switch as an active switch having an off-time as a function of a duty cycle of the PWM signal, while turning on and turning off a second one of the switches as a synchronous switch. The control circuit is also configured to receive signal(s) indicative of currents in each phase of the interleaved circuit arrangement, set an on-time of the second switch equal to the off-time of the first switch when the signal(s) indicate continuous mode operation, and set the on-time of the second switch to a duration less than the off-time of the first switch when the signal(s) indicate discontinuous mode operation.
    Type: Application
    Filed: January 17, 2023
    Publication date: May 18, 2023
    Inventors: Zhihua GU, Siu Chik WONG, Kim Ly KHA
  • Patent number: 11557961
    Abstract: A multi-phase interleaved PFC converter includes at least six switches coupled in a multi-phase interleaved circuit arrangement, and a control circuit. The control circuit is configured to turn on and turn off a first one of the switches according to a PWM signal to operate the first switch as an active switch having an off-time as a function of a duty cycle of the PWM signal, while turning on and turning off a second one of the switches as a synchronous switch. The control circuit is also configured to receive signal(s) indicative of currents in each phase of the interleaved circuit arrangement, set an on-time of the second switch equal to the off-time of the first switch when the signal(s) indicate continuous mode operation, and set the on-time of the second switch to a duration less than the off-time of the first switch when the signal(s) indicate discontinuous mode operation.
    Type: Grant
    Filed: January 20, 2020
    Date of Patent: January 17, 2023
    Assignee: Astec International Limited
    Inventors: Zhihua Gu, Siu Chik Wong, Kim Ly Kha
  • Publication number: 20220060112
    Abstract: A switch-mode AC-DC power converter includes a pair of input terminals, a pair of output terminals, and four switches coupled in a bridgeless totem-pole circuit arrangement between the pair of input terminals and the pair of output terminals. A control circuit is coupled to the four switches and configured to, during a cycle of an AC voltage input, turn on the first switch, turn off the second switch, and apply pulse-width modulation (PWM) control signals to the third and fourth switches. The control circuit is also configured to, during a zero crossing of the AC voltage input, supply a PWM control signal to the fourth switch to reduce a rate of voltage change across the second switch at the zero crossing to reduce common mode noise of the power converter.
    Type: Application
    Filed: November 4, 2021
    Publication date: February 24, 2022
    Inventors: Zhihua Gu, Siu Chik Wong, Kim Ly Kha
  • Patent number: 11183932
    Abstract: A switch-mode AC-DC power converter includes a pair of input terminals, a pair of output terminals, and four switches coupled in a bridgeless totem-pole circuit arrangement between the pair of input terminals and the pair of output terminals. A control circuit is coupled to the four switches and configured to, during a cycle of an AC voltage input, turn on the first switch, turn off the second switch, and apply pulse-width modulation (PWM) control signals to the third and fourth switches. The control circuit is also configured to, during a zero crossing of the AC voltage input, supply a PWM control signal to the fourth switch to reduce a rate of voltage change across the second switch at the zero crossing to reduce common mode noise of the power converter.
    Type: Grant
    Filed: January 8, 2020
    Date of Patent: November 23, 2021
    Assignee: Astec International Limited
    Inventors: Zhihua Gu, Siu Chik Wong, Kim Ly Kha
  • Publication number: 20210226528
    Abstract: A multi-phase interleaved PFC converter includes at least six switches coupled in a multi-phase interleaved circuit arrangement, and a control circuit. The control circuit is configured to turn on and turn off a first one of the switches according to a PWM signal to operate the first switch as an active switch having an off-time as a function of a duty cycle of the PWM signal, while turning on and turning off a second one of the switches as a synchronous switch. The control circuit is also configured to receive signal(s) indicative of currents in each phase of the interleaved circuit arrangement, set an on-time of the second switch equal to the off-time of the first switch when the signal(s) indicate continuous mode operation, and set the on-time of the second switch to a duration less than the off-time of the first switch when the signal(s) indicate discontinuous mode operation.
    Type: Application
    Filed: January 20, 2020
    Publication date: July 22, 2021
    Inventors: Zhihua GU, Siu Chik WONG, Kim Ly KHA
  • Publication number: 20210211049
    Abstract: A switch-mode AC-DC power converter includes a pair of input terminals, a pair of output terminals, and four switches coupled in a bridgeless totem-pole circuit arrangement between the pair of input terminals and the pair of output terminals. A control circuit is coupled to the four switches and configured to, during a cycle of an AC voltage input, turn on the first switch, turn off the second switch, and apply pulse-width modulation (PWM) control signals to the third and fourth switches. The control circuit is also configured to, during a zero crossing of the AC voltage input, supply a PWM control signal to the fourth switch to reduce a rate of voltage change across the second switch at the zero crossing to reduce common mode noise of the power converter.
    Type: Application
    Filed: January 8, 2020
    Publication date: July 8, 2021
    Inventors: Zhihua GU, Siu Chik WONG, Kim Ly KHA