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).

  • Patent number: 10487791
    Abstract: An electric starter system is usable with a powertrain having an engine with a flywheel. The starter system includes a brushless starter motor having a machine temperature, and a solenoid operable for translating a pinion gear into meshed engagement with the flywheel and the starter motor in response to a requested engine start event. A controller has temperature regulation logic that includes a proportional-integral torque control loop. Execution of a method embodied by the logic, in response to the requested engine start event when the machine temperature exceeds a first temperature, causes the controller to determine a required starting torque of the starter motor using the control loop. The controller causes the starter motor to transmit the required starting torque to the engine at a level that reduces the machine temperature below the first temperature.
    Type: Grant
    Filed: May 1, 2018
    Date of Patent: November 26, 2019
    Assignee: GM Global Technology Operations LLC
    Inventors: Lei Hao, Suresh Gopalakrishnan, Chandra S. Namuduri
  • Publication number: 20190356257
    Abstract: A multi-phase switched reluctance motor including a rotor and a stator, an electronic commutator subassembly, and a controller. The electronic commutator subassembly includes an electronic motor control unit, a power inverter, and a rotational position sensor, with the power inverter being electrically connected to the stator of the switched reluctance motor. The controller is in communication with the electronic motor control unit, the power inverter, and the rotational position sensor. The controller includes an instruction set that is executable to characterize operation of the switched reluctance motor, dynamically determine inductance of the switched reluctance motor based upon the characterized operation, and execute a closed-loop torque control routine to control the switched reluctance motor based upon the dynamically determined inductance of the switched reluctance motor.
    Type: Application
    Filed: May 16, 2018
    Publication date: November 21, 2019
    Applicant: GM Global Technology Operations LLC
    Inventors: Suresh Gopalakrishnan, Avoki M. Omekanda, Thomas W. Nehl, Chandra S. Namuduri, Lei Hao
  • Publication number: 20190351778
    Abstract: An apparatus for flexible DC fast charging of an electrified vehicle includes a charge receptacle and a vehicle charging controller programmed to establish a wireless communication with a charging station. The apparatus further includes a reconfigurable energy storage system selectively and electrically connected to the charge receptacle. The reconfigurable energy storage system includes a first rechargeable energy storage device selectively and electrically connected to the charge receptacle, a second rechargeable energy storage device selectively connected to the charge receptacle, and a plurality of low-loss switching devices selectively connected to the first rechargeable energy storage device and the second rechargeable energy storage device.
    Type: Application
    Filed: August 5, 2019
    Publication date: November 21, 2019
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Chandra S. Namuduri, Thomas W. Nehl, Lei Hao, Michael Harpster, Andrew K. Chandler
  • Patent number: 10480674
    Abstract: A core structure for an electromagnetic actuator includes an electrically conductive magnetic core component having a magnetic axis, an outer surface between axially opposite ends and at least one slit arranged between said axially opposite ends through the outer surface.
    Type: Grant
    Filed: March 19, 2015
    Date of Patent: November 19, 2019
    Assignee: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Avoki M. Omekanda, Thomas W. Nehl, Chandra S. Namuduri, Suresh Gopalakrishnan
  • Patent number: 10480476
    Abstract: A starter system includes a brushless electric starter motor and a battery power pack, the motor operatively connectable to an internal combustion engine of a powertrain. A power inverter converts direct current provided from the battery power pack to multi-phase alternating current to drive the motor. A pinion gear with one-way clutch is rotatably driven by the motor and movable between a disengaged position and an engaged position in which the pinion gear is meshingly engaged with a ring gear operatively connected to a crankshaft of the engine. A solenoid is operatively connected to the pinion gear. An electronic control system controls the motor to crank the engine using power provided from the battery power pack, and to separately command the solenoid to a disabled or an enabled state. A method of controlling the starter system controls the motor to crank the engine in a restart following an autostop.
    Type: Grant
    Filed: April 24, 2018
    Date of Patent: November 19, 2019
    Assignee: GM Global Technology Operations LLC
    Inventors: Chandra S. Namuduri, Thomas W. Nehl, Lei Hao
  • Patent number: 10479220
    Abstract: A powertrain includes a motor-generator that is coupled to an engine. A starter mechanism is coupled to the engine. A first energy storage device is disposed in a parallel electrical relationship with the starter mechanism. A second energy storage device is disposed in a parallel electrical relationship with the motor-generator. The electrical circuit exhibits a first electrical resistance between the first energy storage device and the motor-generator, and a second electrical resistance between the second energy storage device and the motor-generator. The first electrical resistance is greater than the second electrical resistance so that electrical energy from the motor-generator more easily flows to the second energy storage device than the first energy storage device, and the motor-generator more easily draws electrical energy from the second energy storage device than from the first energy storage device.
    Type: Grant
    Filed: April 11, 2017
    Date of Patent: November 19, 2019
    Assignee: GM Global Technology Operations LLC
    Inventors: Chandra S. Namuduri, Venkata Prasad Atluri, Suresh Gopalakrishnan
  • Patent number: 10473081
    Abstract: An electric starter system includes a brushless alternating current (AC) starter motor selectively coupled to an engine and having a rotor with a rotor position. A position sensor generates measured position signals indicative of rotor position. A controller is in communication with the sensor. The controller has sensorless logic, e.g., a BEMF, inductance, or high-frequency signal injection method, for generating an estimated rotor position. The controller executes a method in which, below a threshold speed of the starter motor, the controller calibrates the sensorless logic using the measured position signals and controls a torque operation of the starter motor using the measured position signals. Above the threshold speed, the torque operation is controlled solely using the estimated rotor position. A powertrain includes the engine, a transmission, a drive shaft, and a load, along with the electric starter system.
    Type: Grant
    Filed: April 24, 2018
    Date of Patent: November 12, 2019
    Assignee: GM Global Technology Operations LLC
    Inventors: Lei Hao, Suresh Gopalakrishnan, Chandra S. Namuduri
  • Patent number: 10471820
    Abstract: A drivetrain system for a vehicle is described, and includes an internal combustion engine, a geartrain, an electric machine, a power take-off unit, and a driveline. The internal combustion engine is coupled to the geartrain via a disconnect clutch and a torque converter. The geartrain includes a transmission and a differential gearset, including an output member of the transmission coupled to an input member of the differential gearset. The input member of the differential gearset is coupled to a rotor of the electric machine and the power take-off unit. The differential gearset is coupled to first and second intermediate driveshaft members of the driveline to transfer propulsion power to vehicle wheels that are arranged in a front-wheel configuration.
    Type: Grant
    Filed: May 1, 2017
    Date of Patent: November 12, 2019
    Assignee: GM Global Technology Operations LLC
    Inventors: Derek F. Lahr, Farzad Samie, Norman K. Bucknor, Chunhao J. Lee, Dongxu Li, Chandra S. Namuduri, Alexandru Rajala
  • Publication number: 20190338745
    Abstract: An electric starter system is usable with a powertrain having an engine with a flywheel. The starter system includes a brushless starter motor having a machine temperature, and a solenoid operable for translating a pinion gear into meshed engagement with the flywheel and the starter motor in response to a requested engine start event. A controller has temperature regulation logic that includes a proportional-integral torque control loop. Execution of a method embodied by the logic, in response to the requested engine start event when the machine temperature exceeds a first temperature, causes the controller to determine a required starting torque of the starter motor using the control loop. The controller causes the starter motor to transmit the required starting torque to the engine at a level that reduces the machine temperature below the first temperature.
    Type: Application
    Filed: May 1, 2018
    Publication date: November 7, 2019
    Applicant: GM Global Technology Operations LLC
    Inventors: Lei Hao, Suresh Gopalakrishnan, Chandra S. Namuduri
  • Publication number: 20190338744
    Abstract: An electric starter system is used with an engine. The starter system may include a solenoid device coupled to a pinion gear, a brushless starter motor connectable to the engine via the pinion gear during a requested engine start event, and a controller. In response to the start event, when the engine speed is less than a threshold speed, the controller delivers a control current to the solenoid device at a peak current level sufficient for translating the pinion gear into contact with the flywheel. The control current is reduced to a holding current level less than the peak current level after the pinion gear is engaged with the flywheel. Motor torque is commanded from the starter motor, through the pinion gear, and to the flywheel while maintaining the holding current level, and held for a duration sufficient for starting the engine.
    Type: Application
    Filed: May 1, 2018
    Publication date: November 7, 2019
    Applicant: GM Global Technology Operations LLC
    Inventors: Chandra S. Namuduri, Kenneth J. Shoemaker, Chunhao J. Lee, Lei Hao, Thomas W. Nehl, Suresh Gopalakrishnan
  • Publication number: 20190338743
    Abstract: An engine starter system includes a starter including a multi-phase brushless electric motor and an electronic commutator assembly. A controller includes an instruction set that is executable in response to a command to execute an engine starting event. Operation includes determining a desired starting profile, controlling the starter to engage a rotatable member of the engine, and monitoring the rotational speed of the electric motor via a rotor position sensing circuit. The starter inverter is dynamically controlled to control the electric motor to spin the rotatable member of the internal combustion engine responsive to the desired starting profile, including dynamically controlling the starter inverter to control the electric motor to control the spin of the engine responsive to the desired starting profile to prevent occurrence of an engine speed flare event during the engine starting event.
    Type: Application
    Filed: May 1, 2018
    Publication date: November 7, 2019
    Applicant: GM Global Technology Operations LLC
    Inventors: Suresh Gopalakrishnan, Lei Hao, Chandra S. Namuduri, Paul S. Lombardo, Jeffrey R. Aldrich, Chunhao J. Lee, Neeraj S. Shidore
  • Publication number: 20190338742
    Abstract: A method of controlled stopping an internal combustion engine having a stop-start mode and starter assembly includes detecting when the stop-start mode is active. The method also includes monitoring current rotational speed and position of the engine. The method additionally includes determining when the current rotational position is within a predetermined range of a target stop rotational position and the current rotational speed is less than a threshold rotational speed, and afterward energizing the starter assembly to engage the engine. The method also includes establishing a time delay following energizing the starter assembly to confirm engagement of the starter assembly with the engine. Furthermore, the method includes applying a torque by the starter assembly to stop the engine at the target stop position. A vehicle powertrain employing the engine equipped with the stop-start mode, the starter assembly, and an electronic controller configured to execute the method is also provided.
    Type: Application
    Filed: May 1, 2018
    Publication date: November 7, 2019
    Applicant: GM Global Technology Operations LLC
    Inventors: Suresh Gopalakrishnan, Lei Hao, Chandra S. Namuduri, Paul S. Lombardo, Chunhao J. Lee, Alexandru Rajala, Neeraj S. Shidore, Farzad Samie, Norman K. Bucknor, Dongxu Li
  • Publication number: 20190323469
    Abstract: An electric starter system includes a brushless alternating current (AC) starter motor selectively coupled to an engine and having a rotor with a rotor position. A position sensor generates measured position signals indicative of rotor position. A controller is in communication with the sensor. The controller has sensorless logic, e.g., a BEMF, inductance, or high-frequency signal injection method, for generating an estimated rotor position. The controller executes a method in which, below a threshold speed of the starter motor, the controller calibrates the sensorless logic using the measured position signals and controls a torque operation of the starter motor using the measured position signals. Above the threshold speed, the torque operation is controlled solely using the estimated rotor position. A powertrain includes the engine, a transmission, a drive shaft, and a load, along with the electric starter system.
    Type: Application
    Filed: April 24, 2018
    Publication date: October 24, 2019
    Applicant: GM Global Technology Operations LLC
    Inventors: Lei Hao, Suresh Gopalakrishnan, Chandra S. Namuduri
  • Publication number: 20190323472
    Abstract: An electric starter system is usable with an engine and a power inverter module (PIM), e.g., of a powertrain. The starter system includes a polyphase/AC brushless starter motor connected to the PIM via an AC voltage bus and selectively connected to the engine during a requested engine start event. A sensor on the DC voltage bus outputs a signal indicative of a voltage level of the DC voltage bus. The controller executes a method using voltage stabilization logic having a proportional-integral (PI) torque control loop. Logic execution in response to the requested engine starting event causes the controller to control the starter motor, when the bus voltage exceeds a calibrated minimum voltage, using a starting torque determined via the control loop. The commanded starting torque limits inrush current to the starter motor such that the DC voltage bus remains above the minimum voltage.
    Type: Application
    Filed: April 24, 2018
    Publication date: October 24, 2019
    Applicant: GM Global Technology Operations LLC
    Inventors: Lei Hao, Chandra S. Namuduri, Suresh Gopalakrishnan
  • Publication number: 20190323473
    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: Application
    Filed: April 24, 2018
    Publication date: October 24, 2019
    Applicant: GM Global Technology Operations LLC
    Inventors: Chandra S. Namuduri, Lei Hao, Alexandru Rajala, Thomas W. Nehl
  • Publication number: 20190326790
    Abstract: A brushless electric motor includes a motor casing having a first bearing, a motor end-cap including a second bearing, a multi-phase stator assembly, and a rotor assembly having a rotor shaft. The shaft has a first end, a second end, and a knurled section therebetween. The shaft also has a first bearing surface proximate the first end and supported by the first bearing, a second bearing surface proximate the second end and supported by the second bearing, and a rotor position and speed sensor target. The shaft additionally has a sun gear integrated with the shaft proximate the first bearing surface for engaging a partial planetary gear set. The rotor assembly also includes a rotor lamination fixed to the shaft at the knurled section and having opposing first and second sides, and first and second end plates arranged on the respective first and second sides of the rotor lamination.
    Type: Application
    Filed: April 24, 2018
    Publication date: October 24, 2019
    Applicant: GM Global Technology Operations LLC
    Inventors: Lei Hao, Chandra S. Namuduri, Alexandru Rajala, Thomas W. Nehl, Suresh Gopalakrishnan, Avoki M. Omekanda
  • Publication number: 20190323470
    Abstract: A starter system includes a brushless electric starter motor and a battery power pack, the motor operatively connectable to an internal combustion engine of a powertrain. A power inverter converts direct current provided from the battery power pack to multi-phase alternating current to drive the motor. A pinion gear with one-way clutch is rotatably driven by the motor and movable between a disengaged position and an engaged position in which the pinion gear is meshingly engaged with a ring gear operatively connected to a crankshaft of the engine. A solenoid is operatively connected to the pinion gear. An electronic control system controls the motor to crank the engine using power provided from the battery power pack, and to separately command the solenoid to a disabled or an enabled state. A method of controlling the starter system controls the motor to crank the engine in a restart following an autostop.
    Type: Application
    Filed: April 24, 2018
    Publication date: October 24, 2019
    Applicant: GM Global Technology Operations LLC
    Inventors: Chandra S. Namuduri, Thomas W. Nehl, Lei Hao
  • Publication number: 20190323475
    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: Application
    Filed: April 24, 2018
    Publication date: October 24, 2019
    Applicant: GM Global Technology Operations LLC
    Inventors: Chandra S. Namuduri, Lei Hao, Alexandru Rajala, Thomas W. Nehl
  • Publication number: 20190323474
    Abstract: A starter system for a powertrain comprises a brushless electric starter motor operatively connectable to an internal combustion engine. The starter system includes both an ultracapacitor power pack and a battery power pack. A nominal voltage of the ultracapacitor power pack is greater than that of the battery power pack. A DC-DC converter operatively connects the battery power pack and the ultracapacitor power pack and converts direct current at a first voltage level of the battery power pack to direct current at a greater second voltage level of the ultracapacitor power pack. An electronic control system is operable to control the brushless electric starter motor to start the engine using power provided from the ultracapacitor power pack, and to control the DC-DC converter to recharge the ultracapacitor power pack using power provided from the battery power pack through the DC-DC converter. A method of controlling the starter system is included.
    Type: Application
    Filed: April 24, 2018
    Publication date: October 24, 2019
    Applicant: GM Global Technology Operations LLC
    Inventors: Chandra S. Namuduri, Venkata Prasad Atluri, Lei Hao
  • Publication number: 20190326842
    Abstract: A starter includes a three-phase switched reluctance electric motor including a rotor and a stator, a pinion gear, a power inverter that is connected to the stator, and a rotational position sensor. The rotor includes a quantity of rotor poles that is between 6 and 16, and the stator includes a quantity of stator poles that is between 8 and 24. An outer diameter of the electric motor is less than 85 mm. An active length of the motor is less than 50 mm. An airgap distance between the rotor and the stator is between 0.1 mm and 0.5 mm. A ratio between a rotor pole arc and a stator pole arc is at least 1.0:1. A ratio between a stator diameter and a rotor diameter is at least 2.0:1, and a ratio between a stator pole height and a rotor pole height is at least 2.5:1.
    Type: Application
    Filed: April 24, 2018
    Publication date: October 24, 2019
    Applicant: GM Global Technology Operations LLC
    Inventors: Avoki M. Omekanda, Lei Hao, Chandra S. Namuduri, Suresh Gopalakrishnan, Thomas W. Nehl