Patents by Inventor Lakshmi Ravi

Lakshmi Ravi 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: 12176171
    Abstract: Gate control of power semiconductor devices using reduced gate drivers is disclosed. A circuit breaker may include a multitude of transistors, such as insulated gate bipolar transistors (IGBTs), connected in series with one another. Each transistor may be connected to a respective gate resistor. Diodes may be connected between various gate resistors. One or more resistor-capacitor (RC) snubber circuits may be provided in parallel with one or more of the transistors. Likewise, one or more metal-oxide varistors (MOVs) may be connected in parallel to one or more of the transistors. A gate driver (e.g., a single gate drive) may be connected to the one or more diodes and an emitter of at least one of transistors.
    Type: Grant
    Filed: August 10, 2022
    Date of Patent: December 24, 2024
    Assignee: VIRGINIA TECH INTELLECTUAL PROPERTIES, INC.
    Inventors: Jian Liu, Lakshmi Ravi, Dong Dong, Rolando Burgos, Steven Schmalz
  • Publication number: 20230046316
    Abstract: Gate control of power semiconductor devices using reduced gate drivers is disclosed. A circuit breaker may include a multitude of transistors, such as insulated gate bipolar transistors (IGBTs), connected in series with one another. Each transistor may be connected to a respective gate resistor. Diodes may be connected between various gate resistors. One or more resistor-capacitor (RC) snubber circuits may be provided in parallel with one or more of the transistors. Likewise, one or more metal-oxide varistors (MOVs) may be connected in parallel to one or more of the transistors. A gate driver (e.g., a single gate drive) may be connected to the one or more diodes and an emitter of at least one of transistors.
    Type: Application
    Filed: August 10, 2022
    Publication date: February 16, 2023
    Inventors: Jian Liu, Lakshmi Ravi, Dong Dong, Rolando Burgos, Steven Schmalz
  • Patent number: 11271492
    Abstract: An inverter with a modular bus assembly is described. In various embodiments, the modular bus assembly includes a laminated motherboard and a plurality of capacitor daughtercards. The laminated motherboard can be configured to interface a plurality of phase-leg modules and a plurality of capacitor daughtercards through a plurality of terminals and connectors located on a bottom side or a top side of the laminated motherboard. The laminated motherboard includes a layer stack with a plurality of conductor layers. Each of the plurality of conductor layers is implemented with a net spacing from a neighboring plated through hole (PTH) based at least in part on differences in potential to be applied to each of the plurality of conductor layers as compared to a potential to be applied to the PTH. Embedded shield polygons can be implemented on the laminated motherboard to mitigate surface discharge at surface terminal (PTH/SMT) triple junctions.
    Type: Grant
    Filed: July 27, 2020
    Date of Patent: March 8, 2022
    Assignee: VIRGINA TECH INTELLECTUAL PROPERTIES, INC.
    Inventors: Lakshmi Ravi, Joshua Stewart, Dong Dong, Rolando Burgos
  • Publication number: 20220029549
    Abstract: An inverter with a modular bus assembly is described. In various embodiments, the modular bus assembly includes a laminated motherboard and a plurality of capacitor daughtercards. The laminated motherboard can be configured to interface a plurality of phase-leg modules and a plurality of capacitor daughtercards through a plurality of terminals and connectors located on a bottom side or a top side of the laminated motherboard. The laminated motherboard includes a layer stack with a plurality of conductor layers. Each of the plurality of conductor layers is implemented with a net spacing from a neighboring plated through hole (PTH) based at least in part on differences in potential to be applied to each of the plurality of conductor layers as compared to a potential to be applied to the PTH. Embedded shield polygons can be implemented on the laminated motherboard to mitigate surface discharge at surface terminal (PTH/SMT) triple junctions.
    Type: Application
    Filed: July 27, 2020
    Publication date: January 27, 2022
    Inventors: Lakshmi Ravi, Joshua Stewart, Dong Dong, Rolando Burgos