Patents by Inventor Rashmi Prasad

Rashmi Prasad 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).

  • Publication number: 20240146075
    Abstract: An electrified vehicle may include a plurality of electric drive units, a plurality of battery packs, a plurality of charge ports and a plurality of controllable switches. The switches may be controlled to flexibly configure power transfer into and out of the vehicle through one or more charge ports affecting one or more battery packs in parallel or individually passively or actively through inverter integrated converter charge transfer.
    Type: Application
    Filed: October 28, 2022
    Publication date: May 2, 2024
    Inventors: Chandra S. Namuduri, Rashmi Prasad, Minh-Khai Nguyen
  • Patent number: 11970072
    Abstract: An example of a vehicle electrical system includes a rechargeable energy storage system (RESS) having a first voltage and a power inverter electrically connected to the RESS. The system further includes an electric motor having a plurality of machine windings with each of the machine windings including a polyphase terminal electrically connected to the power inverter. The electric motor further includes a neutral terminal separate from the polyphase terminals. The system further includes an accessory load electrically connected to the power inverter and the neutral terminal of the electric motor, with the accessory load requiring a second voltage that is below the first voltage. A current flows through the machine windings to step down the first voltage to the second voltage. The power inverter is configured to cycle between first and second operational states, such that the power inverter steps down the first voltage to the second voltage.
    Type: Grant
    Filed: March 22, 2021
    Date of Patent: April 30, 2024
    Assignee: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Rashmi Prasad, Chandra S. Namuduri
  • Publication number: 20240128782
    Abstract: A method for charging a battery pack via an offboard energy source uses an interleaved boost converter and closed-loop control. The energy source outputs a charging current via a DC charge port during a direct current fast-charging (DCFC) process. A controller detects a voltage disparity condition in which a voltage capability of the battery pack exceeds a voltage capability of the energy source. In response to this condition, a rise of the charging current over time is recorded as a current trajectory and an open-loop equivalent time constant is extracted from the current trajectory. A time constant of the PI control block is set substantially equal to the equivalent time constant. The PIM is controlled in closed-loop using proportional-integral control. The charging current is controlled in a continuous current conduction mode during the DCFC process.
    Type: Application
    Filed: October 18, 2022
    Publication date: April 18, 2024
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Chandra S. Namuduri, Rashmi Prasad
  • Patent number: 11962173
    Abstract: A system for use with a direct current fast-charging (DCFC) station includes a controller and battery system. The battery system includes first and second battery packs, and first, second, and third switches. The switches have ON/OFF conductive states commanded by the controller to connect the battery packs in a parallel-connected (P-connected) or series-connected (S-connected) configuration. An electric powertrain with one or more electric machines is powered via the battery system. First and second charge ports of the system are connectable to the station via a corresponding charging cable. The first charge port receives a low or high charging voltage from the station. The second charge port receives a low charging voltage. When the station can supply the high charging voltage to the first charge port, the controller establishes the S-connected configuration via the switches, and thereafter charges the battery system solely via the first charge port.
    Type: Grant
    Filed: April 12, 2022
    Date of Patent: April 16, 2024
    Assignee: GM Global Technology Operations LLC
    Inventors: Lei Hao, Yue-Yun Wang, Suresh Gopalakrishnan, Chandra S. Namuduri, Rashmi Prasad, Madhusudan Raghavan
  • Publication number: 20240092203
    Abstract: A charging system of a vehicle includes a first conversion device of a first drive system of the vehicle, the first conversion device connected to a first electric motor. The system also includes a second conversion device of a second drive system of the vehicle, the second conversion device connected to a second electric motor. The first drive system and the second drive system are connected to a battery system of the vehicle. The system also includes a switching assembly including a plurality of switches configured to selectively connect the first electric motor and/or the second electric motor to a charge port of the vehicle, and a controller configured to control the switching assembly to define a conversion circuit that includes components of the first drive system and/or the second drive system, and control the conversion circuit to regulate an output voltage and supply power to an energy storage system.
    Type: Application
    Filed: September 20, 2022
    Publication date: March 21, 2024
    Inventors: Chandra S. Namuduri, Rashmi Prasad
  • Patent number: 11912146
    Abstract: A battery charging system includes: an electric motor including stator coils; a battery; a charge port configured to receive power from charging stations by wire; first and second electrical conductors connected between the battery and the charge port; an inverter module including (a) inputs connected to receive power from the battery and (b) outputs connected to the electric motor; a third electrical conductor; and a switch configured to electrically connect and disconnect a first end of the third electrical conductor to and from the first electrical conductor, where the third electrical conductor includes a second end that is connected to at least one of the stator coils via one of the outputs of the inverter module.
    Type: Grant
    Filed: April 23, 2021
    Date of Patent: February 27, 2024
    Assignee: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Rashmi Prasad, Chandra S. Namuduri
  • Patent number: 11890958
    Abstract: A system in a vehicle includes a first winding section including first two or more windings and a second winding section including second two or more windings. Each of the second two or more windings corresponds to one of the first two or more windings of the first winding section. The system also includes an inverter including a high side switch and a low side switch corresponding to each of the first two or more windings. The inverter is coupled to a battery of the vehicle and boosts a voltage of a direct current (DC) charger during charging of the battery with the DC charger, converts alternating current (AC) from an AC grid to DC during charging of the battery with the AC grid, and converts DC to AC during supply of the AC grid by the battery.
    Type: Grant
    Filed: May 10, 2022
    Date of Patent: February 6, 2024
    Assignee: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Rashmi Prasad, Chandra S. Namuduri, Lei Hao, Suresh Gopalakrishnan
  • Publication number: 20240022946
    Abstract: A slew rate controllable system for powering an electric machine. The system may include a plurality of power transistors operable for converting a direct current (DC) input into an alternating current (AC) output suitable for electrically powering the electric machine. The system may further include a gate drive system operable for controlling a slew rate associated with transitioning the power transistors between the opened and closed states.
    Type: Application
    Filed: September 28, 2023
    Publication date: January 18, 2024
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Yilun Luo, Khorshed Mohammed Alam, Eric B. Gach, Hong Nguyen, Chandra S. Namuduri, Rashmi Prasad, Junghoon Kim
  • Patent number: 11872906
    Abstract: An electric propulsion system includes a rotary electric machine having an output member, a rechargeable energy storage system (“RESS”) connected to the electric machine, a user interface device, and a controller. The RESS includes multiple battery modules and a switching circuit, the latter being configured, in response to electronic switching control signals, to connect the battery modules in a parallel-connected configuration or a series-connected configuration, as a selected battery configuration. The user interface device receives an operator-requested drive mode request as an electrical signal indicative of a desired drive mode of the electric propulsion system.
    Type: Grant
    Filed: May 6, 2021
    Date of Patent: January 16, 2024
    Assignee: GM Global Technology Operations LLC
    Inventors: Alireza Fatemi, Thomas W. Nehl, Chandra S. Namuduri, Lei Hao, Norman K. Bucknor, Rashmi Prasad
  • Patent number: 11876034
    Abstract: A power module is provided and includes first stack, second stack, and third stacks of layers, a heat pipe, and at least one cold plate or heat sink. The third stack of layers is disposed between the first and second stacks of layers and includes a first semiconductor die, a second semiconductor die and a center spacer layer disposed between the first semiconductor die and the second semiconductor die. The heat pipe extends at least partially into the center spacer layer. The at least one cold plate or heat sink receives thermal energy from the first stack of layers and the second stack of layers. The first stack of layers, the second stack of layers, the third stack of layers, the heat pipe and the at least one cold plate or heat sink facilitate dual sided cooling of each of the first semiconductor die and the second semiconductor die.
    Type: Grant
    Filed: March 29, 2021
    Date of Patent: January 16, 2024
    Assignee: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Muhammad H. Alvi, Ming Liu, Rashmi Prasad, Anthony M. Coppola
  • Patent number: 11870433
    Abstract: An electronic solid-state switch assembly includes a base plate and a heat exchanger; an electrically insulating layer and a direct bonded substrate affixed to the base plate; a first terminal and a second terminal; a plurality of power transistors; a plurality of gate drivers; a communication interface, a current sensor, and a snubber circuit; and a controller. The plurality of gate drivers are operatively coupled to the plurality of power transistors. The plurality of power transistors are arranged in parallel on the direct bonded substrate between the first terminal and the second terminal. The plurality of power transistors are electrically connected to the first terminal and to the second terminal. The controller is in communication with the plurality of gate drivers, the current sensor, and the communication interface. The controller is configured to control, via the plurality of gate drivers, the plurality of power transistors.
    Type: Grant
    Filed: May 4, 2022
    Date of Patent: January 9, 2024
    Assignee: GM Global Technology Operations LLC
    Inventors: Rashmi Prasad, Chandra S. Namuduri, Muhammad H. Alvi, Ronald O. Grover, Jr.
  • Patent number: 11865945
    Abstract: A rechargeable energy storage system may include a series arrangement of a plurality of batteries coupled to a first DC bus at a first DC voltage. A DC to DC converter may include a multi-input DC input stage coupled to a multi-output DC output stage. The multi-input DC input stage may include multiple distributed DC inputs, each distributed DC input being coupled to a respective one of the plurality of batteries. The multi-output DC output stage may include multiple aggregated DC outputs. At least one controllable switch may couple one or more of the multiple aggregated DC outputs to one or more other DC buses.
    Type: Grant
    Filed: June 14, 2022
    Date of Patent: January 9, 2024
    Assignee: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Mohamed Kamel, Chandra S. Namuduri, Rashmi Prasad, Muhammad Hussain Alvi, Lyall Kenneth Winger
  • Patent number: 11860196
    Abstract: A detection system for a capacitor of a power inverter of an electric vehicle includes a protection circuit including a current sensor and a power switch having a first terminal in communication with a battery system of the electric vehicle. The protection circuit is configured to selectively generate a pulse and to sense a measured current flowing through the power switch. A voltage sensor configured to sense a measured voltage across the capacitor. A controller in communication with the voltage sensor and the protection circuit is configured to estimate a capacitance value of the capacitor based on the measured current and the measured voltage.
    Type: Grant
    Filed: December 1, 2021
    Date of Patent: January 2, 2024
    Assignee: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Muhammad Hussain Alvi, Chandra S. Namuduri, Rashmi Prasad, Renato Amorim Torres
  • Publication number: 20230398903
    Abstract: A rechargeable energy storage system may include a series arrangement of a plurality of batteries coupled to a first DC bus at a first DC voltage. A DC to DC converter may include a multi-input DC input stage coupled to a multi-output DC output stage. The multi-input DC input stage may include multiple distributed DC inputs, each distributed DC input being coupled to a respective one of the plurality of batteries. The multi-output DC output stage may include multiple aggregated DC outputs. At least one controllable switch may couple one or more of the multiple aggregated DC outputs to one or more other DC buses.
    Type: Application
    Filed: June 14, 2022
    Publication date: December 14, 2023
    Inventors: Mohamed Kamel, Chandra S. Namuduri, Rashmi Prasad, Muhammad Hussain Alvi, Lyall Kenneth Winger
  • Publication number: 20230402870
    Abstract: A method and apparatus for electrical energy transfer between a pair of series connected batteries coupled between positive and negative DC rails of a power inverter operatively connected to a plurality of stator phase windings of a stator winding of a motor may include coupling a midpoint of the pair of series connected batteries to the stator winding of the motor, and controlling the power inverter to operate the power inverter and the stator winding as a switched-mode power converter to charge at least one of the stator phase windings from one of the pair of series connected batteries and to discharge the at least one of the stator phase windings to the other of the pair of series connected batteries.
    Type: Application
    Filed: June 14, 2022
    Publication date: December 14, 2023
    Inventors: Mohamed Kamel, Muhammad Hussain Alvi, Alireza Fatemi, Chandra S. Namuduri, Rashmi Prasad
  • Patent number: 11840153
    Abstract: Examples described herein provide a method that includes determining whether a charging station for charging a battery of a vehicle is operating in a first high voltage mode or a second high voltage mode. The method further includes, responsive to determining that the charging station is operating in the first high voltage mode: enabling an electric motor and a traction power inverter of the vehicle to operate as a boost converter to boost an accessory bus voltage of the vehicle while charging in the first high voltage mode, and charging the battery of the vehicle by supplying electric power, at a first high voltage, from the charging station to the battery.
    Type: Grant
    Filed: July 18, 2022
    Date of Patent: December 12, 2023
    Assignee: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Chandra S. Namuduri, Rashmi Prasad
  • Publication number: 20230378776
    Abstract: A battery system includes a battery pack configured to be selectively connected to an output terminal of the battery system and a DCFC receptacle, a first contactor that is connected between the DCFC receptacle and a first terminal of the battery pack, and a first SSR connected in series with the first contactor between the DCFC receptacle and the first terminal of the battery pack. The first SSR has an open state where current from the DCFC receptacle to the battery pack is interrupted and a dosed state where current flows from the DCFC receptacle to the battery pack, the first SSR is configured to transition from the dosed state to the open state prior to the first contactor, and current only flows from the DCFC receptacle to the battery pack when both the first contactor and the first SSR are in the closed state.
    Type: Application
    Filed: May 20, 2022
    Publication date: November 23, 2023
    Inventors: Rashmi PRASAD, Chandra S. NAMUDURI
  • Publication number: 20230365012
    Abstract: A charging system for a vehicle includes a conversion device configured to transfer an electric charge between a battery assembly of the vehicle and an energy storage system, the battery assembly having a first voltage and the energy storage system having a second voltage, the conversion device including a scalable buck-boost system having a plurality of buck-boost modules. Each buck-boost module of the plurality of buck-boost modules includes a set of switches and an inductor. The charging system also includes a controller configured to operate one or more buck-boost modules of the plurality of buck-boost modules during transfer of charge between the battery assembly and the energy storage system.
    Type: Application
    Filed: May 12, 2022
    Publication date: November 16, 2023
    Inventors: Chandra S. Namuduri, Lei Hao, Rashmi Prasad, Rasoul Hosseini, Venkata Prasad Atluri, Chengwu Duan
  • Publication number: 20230365016
    Abstract: A system in a vehicle includes a first winding section including first two or more windings and a second winding section including second two or more windings. Each of the second two or more windings corresponds to one of the first two or more windings of the first winding section. The system also includes an inverter including a high side switch and a low side switch corresponding to each of the first two or more windings. The inverter is coupled to a battery of the vehicle and boosts a voltage of a direct current (DC) charger during charging of the battery with the DC charger, converts alternating current (AC) from an AC grid to DC during charging of the battery with the AC grid, and converts DC to AC during supply of the AC grid by the battery.
    Type: Application
    Filed: May 10, 2022
    Publication date: November 16, 2023
    Inventors: Rashmi Prasad, Chandra S. Namuduri, Lei Hao, Suresh Gopalakrishnan
  • Publication number: 20230364996
    Abstract: Examples described herein provide a method that includes performing an electrical degradation analysis for a power inverter. The method further includes performing a thermal degradation analysis on the power inverter. The method further includes, responsive to at least one of a result of the electrical degradation analysis being indicative of an electrical issue of the power inverter or a result of the thermal degradation analysis being indicative of a thermal issue of the power inverter, implementing a corrective action for the power inverter.
    Type: Application
    Filed: May 10, 2022
    Publication date: November 16, 2023
    Inventors: Jiyu Zhang, Bojian Cao, Nomar S. Gonzalez Santini, Jeffrey Scott Piasecki, Tanvi Nagarale, Muhammad Hussain Alvi, Rashmi Prasad