Patents by Inventor Chandra S. Namuduri

Chandra S. Namuduri 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: 20210234447
    Abstract: An electric machine includes a machine rotor circumscribed by a machine stator, and having a rotor shaft, rotor stack, and end cap which rotate about an axis. The end cap includes lobes equal in number to a number of pole pairs of the machine rotor. A position sensor assembly has a predetermined alignment with the machine rotor and stator. The sensor assembly includes a sensor rotor formed by the lobes and a sensor stator having a printed circuit board with conductive sine and cosine traces. Machine rotor rotation causes the sensor assembly to output an unmodulated sine and cosine signals to a controller, which then calculates a calibrated reference angle. A magnetic axis of an electrical phase of the machine is aligned with and bisects a peak of the sine trace. A direct axis of the machine rotor aligns with an edge of a lobe.
    Type: Application
    Filed: January 28, 2020
    Publication date: July 29, 2021
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Suresh Gopalakrishnan, Chandra S. Namuduri, Alexandru Rajala, Thomas W. Nehl, Xiaohui Du, Edward L. Kaiser
  • Patent number: 11071225
    Abstract: An integrated smart relay assembly includes a case and an electronic solid-state switch disposed inside the case and a gate driver circuit electrically connected to the electronic solid-state switch. The gate driver circuit is configured to drive the electronic solid-state switch with a predetermined gate voltage and a predetermined gate current. The relay assembly further includes a protection circuit electrically connected to the gate driver circuit. The protection circuit is configured to protect the electronic solid-state switch against over-voltage, short circuit, and overheating. The relay assembly further includes a communication interface integrated with the electronic solid-state switch. Each of the protection circuit, electronic solid-state switch, and the communication interface is disposed inside the case.
    Type: Grant
    Filed: October 17, 2019
    Date of Patent: July 20, 2021
    Assignee: GM Global Technology Operations LLC
    Inventors: Chandra S. Namuduri, Rashmi Prasad
  • Patent number: 11015564
    Abstract: A starter assembly includes a multi-phase brushless electric motor including a stator, a rotor disposed on a rotatable shaft, and a motor endcap disposed at a first end of the stator. An electronic commutator assembly includes a sensing circuit, a control electronics subassembly, a power electronics subassembly and a heat sink. The sensing circuit is disposed adjacent to the second end of the rotatable shaft. The control electronics subassembly, the power electronics subassembly and the heat sink are disposed on disk-shaped devices arranged in a stacked configuration orthogonal to the axis defined by the rotatable shaft. The control electronics subassembly is disposed adjacent to the sensing circuit, and the power electronics subassembly is disposed adjacent to the control electronics subassembly. The control electronics subassembly is interposed between the power electronics subassembly and the sensing circuit. The heat sink is disposed adjacent to the power electronics subassembly.
    Type: Grant
    Filed: April 24, 2018
    Date of Patent: May 25, 2021
    Assignee: GM Global Technology Operations LLC
    Inventors: Chandra S. Namuduri, Lei Hao, Alexandru Rajala, Thomas W. Nehl
  • Publication number: 20210143811
    Abstract: A circuitry includes an electronic solid-state switch including a first power terminal and a second power terminal and a driver and switch protection system electrically connected to the electronic solid-state switch. The driver and switch protection system includes an isolated bias power circuit configured to output a direct current voltage of at least fifteen volts, a current buffer circuit electrically connected between the isolated bias power circuit and the electronic solid-state switch, and a snubber circuit electrically connected to the first power terminal and the second power terminal.
    Type: Application
    Filed: November 7, 2019
    Publication date: May 13, 2021
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Chandra S. Namuduri, Rashmi Prasad
  • Publication number: 20210129687
    Abstract: A system for utilizing a deployable flex range battery to augment a primary battery is provided. The system includes a flex electronics bay. The flex electronics bay is electrically connected to an electrical sub-system including the primary battery and includes a DC-DC converter operable to change a voltage of electric power and at least one battery connection terminal. The system further includes the deployable flex range battery removably connected to the at least one battery connection terminal and a flex electronics bay controller programmed to selectively supply electric power from the flex electronics bay to the electrical sub-system.
    Type: Application
    Filed: November 1, 2019
    Publication date: May 6, 2021
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Venkata Prasad Atluri, Hanho Yun, Neeraj S. Shidore, Chandra S. Namuduri, Venkatesh Gopalakrishnan
  • Publication number: 20210129686
    Abstract: An electric propulsion system includes a battery pack and a DC-DC converter. The converter has a bypass switch and semiconductor switches. A traction power inverter module (“TPIM”) rectifies a DC bus voltage on the voltage bus to produce an AC bus voltage. An electric machine is connected to the TPIM and energized via the AC bus voltage. A controller calculates required output power from the converter based on a requested operating mode, and speed and torque of the electric machine. When the output power exceeds a threshold, the bypass switch closes to bypass the converter. When the output power is less than the threshold, the controller uses a minimum loss voltage from a loss map as a target control voltage of the converter to optimize efficiency of the electric propulsion system.
    Type: Application
    Filed: November 6, 2019
    Publication date: May 6, 2021
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Lei Hao, Chandra S. Namuduri, Suresh Gopalakrishnan, Chengwu Duan, Norman K. Bucknor
  • Publication number: 20210135588
    Abstract: An AC electronic solid-state switch includes an electrically insulating and thermally conductive layer, a first electrically conductive trace, a second electrically conductive trace, and a plurality of semiconductor dies each electrically connected to the first electrically conductive trace and the second electrically conductive trace. Each of the plurality of semiconductor dies forms a MOSFET, IGBT or other types of electronically controllable switch. The AC electronic solid-state switch further includes a common drain conductor that is electrically connected to each drain terminal of the plurality of semiconductor dies. The AC electronic solid-state switch is configured to block between 650 volts and 1700 volts in the off-state in a first direction and a second direction, the second direction being opposite the first direction, and the AC electronic solid-state switch is configured to carry at least 500 A continuously in the on-state with a voltage drop of less than 2V.
    Type: Application
    Filed: November 5, 2019
    Publication date: May 6, 2021
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Rashmi Prasad, Chandra S. Namuduri
  • Patent number: 10998840
    Abstract: An electric drive system includes a battery pack, a power inverter module (“PIM”), an electric machine, a switching circuit, and a controller. The electric machine has three or more phase legs. The PIM has a DC-side connected to the battery pack, and an alternating current (“AC”)-side connected to the electric machine. The switching circuit includes AC switches, and for each phase leg also includes three or more winding sections each electrically connectable to or disconnectable from the battery pack and PIM via the AC switches. The controller commands a binary switching state of each respective AC switch based on the rotary speed to implement one of three different speed-based operating modes of the electric machine, and to thereby vary a conductive path from the PIM to the electric machine through one or more of the connected winding sections.
    Type: Grant
    Filed: September 13, 2019
    Date of Patent: May 4, 2021
    Assignee: GM Global Technology Operations LLC
    Inventors: Lei Hao, Chandra S. Namuduri, Rashmi Prasad
  • Publication number: 20210120693
    Abstract: An integrated smart relay assembly includes a case and an electronic solid-state switch disposed inside the case and a gate driver circuit electrically connected to the electronic solid-state switch. The gate driver circuit is configured to drive the electronic solid-state switch with a predetermined gate voltage and a predetermined gate current. The relay assembly further includes a protection circuit electrically connected to the gate driver circuit. The protection circuit is configured to protect the electronic solid-state switch against over-voltage, short circuit, and overheating. The relay assembly further includes a communication interface integrated with the electronic solid-state switch. Each of the protection circuit, electronic solid-state switch, and the communication interface is disposed inside the case.
    Type: Application
    Filed: October 17, 2019
    Publication date: April 22, 2021
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Chandra S. Namuduri, Rashmi Prasad
  • Publication number: 20210111648
    Abstract: A system includes a position sensor configured to detect positions of a rotor of a starter motor relative to the position sensor and to output signals indicating the detected positions and a controller configured to rotate the rotor to a plurality of predetermined positions relative to a stator of the starter motor, determine sensed positions of the rotor based on the signals output by the position sensor, and calculate an initial detected position of the rotor based on relationships between the determined sensed positions of the rotor and an expected angular distance between adjacent ones of the predetermined positions.
    Type: Application
    Filed: October 9, 2019
    Publication date: April 15, 2021
    Inventors: Lei HAO, Chandra S. NAMUDURI
  • Publication number: 20210086646
    Abstract: A dual-voltage charging station system for an alternating current (“AC”) power supply and a mobile platform having a charging port includes a charge coupler, an AC-to-DC conversion stage, a cable, and a controller. The charge coupler has AC pins and direct current (“DC”) pins configured to engage with respective AC and DC receptacles of the charging port. The conversion stage is connected to the charge coupler and the AC power supply, converts the supply voltage to a DC charging voltage, and relays an appropriate AC or DC accessory voltage. The cable connects to the charge coupler such that the AC pins receive the accessory voltage and the DC pins receive the DC charging voltage. The controller simultaneously delivers the accessory voltage and the DC voltage to the mobile platform via the AC pins and the DC pins, respectively.
    Type: Application
    Filed: September 23, 2019
    Publication date: March 25, 2021
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Rashmi Prasad, Chandra S. Namuduri
  • Publication number: 20210078442
    Abstract: A battery system includes first and second battery packs connected to positive and negative DC voltage bus rails, a contactor switch connected between the battery packs, a solid-state switch in series with the contactor switch, and a controller. The controller determines characteristic values of the switches, including a respective temperature, voltage, and current value for each. The controller also detects a predetermined electrical fault condition of the contactor switch using the characteristic values, and executes a control action in response to the electrical fault condition. The control action includes opening the semi-conductor switch to thereby interrupt a flow of current between the first and second battery packs. A mobile platform includes road wheels connected to a body, a rotary electric machine configured to power the road wheels and thereby propel the mobile platform, and the battery pack, switches, and controller.
    Type: Application
    Filed: September 13, 2019
    Publication date: March 18, 2021
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Rashmi Prasad, Chandra S. Namuduri
  • Publication number: 20210083612
    Abstract: An electric drive system includes a battery pack, a power inverter module (“PIM”), an electric machine, a switching circuit, and a controller. The electric machine has three or more phase legs. The PIM has a DC-side connected to the battery pack, and an alternating current (“AC”)-side connected to the electric machine. The switching circuit includes AC switches, and for each phase leg also includes three or more winding sections each electrically connectable to or disconnectable from the battery pack and PIM via the AC switches. The controller commands a binary switching state of each respective AC switch based on the rotary speed to implement one of three different speed-based operating modes of the electric machine, and to thereby vary a conductive path from the PIM to the electric machine through one or more of the connected winding sections.
    Type: Application
    Filed: September 13, 2019
    Publication date: March 18, 2021
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Lei Hao, Chandra S. Namuduri, Rashmi Prasad
  • Patent number: 10940771
    Abstract: An electric propulsion system includes a polyphase rotary electric machine that imparts motor torque to a load, a traction power inverter module (“TPIM”) connected to the electric machine, a reconfigurable energy storage system (“RESS”) connected to the TPIM, and a controller. The RESS has multiple battery modules and a switching circuit. The battery modules are connectable in a series-connected (“P-connected”) configuration at a first/low battery voltage level, and a series-connected (“S-connected”) configuration at a second/high battery voltage level that exceeds the first voltage. The controller determines power losses of the electric propulsion system at the first and second battery voltage levels, receives a commanded output torque and output speed of the electric machine, and selects the S-connected or P-connected configuration based on the predetermined power loss and commanded output torque and speed.
    Type: Grant
    Filed: October 17, 2019
    Date of Patent: March 9, 2021
    Assignee: GM Global Technology Operations LLC
    Inventors: Alireza Fatemi, Thomas W. Nehl, Chandra S. Namuduri, Lei Hao, Norman K. Bucknor
  • Patent number: 10917030
    Abstract: An electric drive system includes a battery pack, a power inverter module (“PIM”), an electric machine, a switching circuit, and a controller. The electric machine has three or more phase legs. The PIM has a DC-side connected to the battery pack, and an alternating current (“AC”)-side connected to the electric machine. The switching circuit includes AC switches. For each phase leg the circuit also includes three or more winding sections each electrically connectable to or disconnectable from the PIM via the AC switches. The controller commands a binary switching state of each respective AC switch based on the rotary speed to implement one of four different speed-based operating modes of the electric machine, and to thereby vary a conductive path from the PIM to the electric machine through one or more of the connected winding sections.
    Type: Grant
    Filed: September 13, 2019
    Date of Patent: February 9, 2021
    Assignee: GM Global Technology Operations LLC
    Inventors: Lei Hao, Chandra S. Namuduri, Rashmi Prasad
  • Publication number: 20210036643
    Abstract: A current command module is configured to, based on a direct current (DC) bus voltage for an electric motor of the vehicle, generate a d-axis current command for the electric motor and a q-axis current command for the electric motor. A voltage command module configured to generate voltage commands based on the d-axis current command and the q-axis current command. A battery switching control module is configured to: determine a voltage operating state of a battery based on the voltage commands; compare a battery parameter to at least one of a predetermined voltage parameter and a predetermined current parameter during a dwell time when a plurality of switches of the battery are open; and generate a switch control signal to transition at least one switch of the plurality of switches to cause the battery to operate in the voltage operating state based on the comparison.
    Type: Application
    Filed: July 31, 2019
    Publication date: February 4, 2021
    Inventors: Yue-Yun WANG, Lei HAO, Alireza FATEMI, Thomas W. NEHL, Chandra S. NAMUDURI
  • Patent number: 10900458
    Abstract: A method of stopping an engine crankshaft includes selecting a target angular position at which the engine crankshaft is to be stopped and detecting an actual angular position of the engine crankshaft and a rotational speed of the engine crankshaft. A stopping torque in calculated based on the actual angular position of the engine crankshaft and the rotational speed of the engine crankshaft. The stopping torque is applied to the engine crankshaft via a motor/generator operably connected to the engine crankshaft. The engine crankshaft is stopped at the target angular position via the application of the stopping torque.
    Type: Grant
    Filed: May 8, 2019
    Date of Patent: January 26, 2021
    Assignee: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Suresh Gopalakrishnan, Paul S. Lombardo, David W. Walters, Chunhao J. Lee, Chandra S. Namuduri, Neeraj S. Shidore, Thomas W. Nehl
  • Publication number: 20210017943
    Abstract: An electric starter system is disclosed for use with an engine having a flywheel. The electric starter system includes a pinion gear and a solenoid device coupled to the pinion gear. The solenoid device is movable between a pre-engaged position when the pinion gear is moved into engagement with the flywheel and a disengaged position when the pinion gear is disengaged from the flywheel. A brushless starter motor is selectively connectable to the flywheel of the engine via the pinion gear during a requested engine start event. A latch mechanism is selectively engageable with the solenoid device. The latch mechanism is moveable between a latched position in which the solenoid device is mechanically held in the pre-engaged position and an unlatched position in which the solenoid device is released for movement to the disengaged position.
    Type: Application
    Filed: July 15, 2019
    Publication date: January 21, 2021
    Inventors: Farzad Samie, Chunhao J. Lee, Lei Hao, Chandra S. Namuduri
  • Patent number: 10895237
    Abstract: An electric starter system is disclosed for use with an engine having a flywheel. The electric starter system includes a pinion gear and a solenoid device coupled to the pinion gear. The solenoid device is movable between a pre-engaged position when the pinion gear is moved into engagement with the flywheel and a disengaged position when the pinion gear is disengaged from the flywheel. A brushless starter motor is selectively connectable to the flywheel of the engine via the pinion gear during a requested engine start event. A latch mechanism is selectively engageable with the solenoid device. The latch mechanism is moveable between a latched position in which the solenoid device is mechanically held in the pre-engaged position and an unlatched position in which the solenoid device is released for movement to the disengaged position.
    Type: Grant
    Filed: July 15, 2019
    Date of Patent: January 19, 2021
    Assignee: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Farzad Samie, Chunhao J. Lee, Lei Hao, Chandra S. Namuduri
  • Patent number: 10886817
    Abstract: A starter assembly includes a partial planetary gear set connected to a pinion gear slidable along a first axis. The starter also includes a motor casing housing a brushless electric motor and having a first bearing. The motor includes multi-phase stator and rotor assemblies arranged inside the casing concentrically relative to the first axis. The rotor assembly has a rotor with a shaft supported by the first bearing and connected to a sun gear engaging the gear set, and a rotor position and speed sensor target. The starter additionally includes a motor end-cap for mating with and enclosing the motor casing and having a second bearing supporting the shaft. The starter also includes an electronics cover with a power connector for mating with the end-cap and housing an electronic commutator assembly. The commutator assembly includes power electronics, and control processor electronics arranged between the end-cap and the power electronics.
    Type: Grant
    Filed: April 24, 2018
    Date of Patent: January 5, 2021
    Assignee: GM Global Technology Operations LLC
    Inventors: Chandra S. Namuduri, Lei Hao, Alexandru Rajala, Thomas W. Nehl