Patents by Inventor Suresh Gopalakrishnan

Suresh Gopalakrishnan 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: 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: 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
  • 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
  • Patent number: 10408184
    Abstract: An electric starter system for a powertrain or other system having an engine includes a solenoid device coupled to a pinion gear, a brushless starter motor, and a controller. The starter motor has actual machine speed, and is connectable to the flywheel via the pinion gear during a change-of-mind event when a commanded engine auto-stop sequence is interrupted before completion. When engine speed exceeds a threshold speed and is less than a calibrated starting speed, the controller executes a method in which closed-loop speed control of the starter motor is enabled using the engine speed as a reference value until an effective machine speed is within a permissible speed delta of engine speed. The controller causes the solenoid device to translate the pinion gear into engagement with the flywheel and starter motor, disables closed-loop speed control, and commands the starter motor to start the engine.
    Type: Grant
    Filed: May 1, 2018
    Date of Patent: September 10, 2019
    Assignee: GM Global Technology Operations LLC
    Inventors: Chandra S. Namuduri, Lei Hao, Suresh Gopalakrishnan
  • Patent number: 10330070
    Abstract: A starter for an internal combustion engine includes a multi-phase brushless electric motor, a controller and an inverter. A method for controlling the starter includes determining initial current commands for operating the electric motor in response to an activation command. Electrical current supplied to the electric motor and a rotational position of an output member of the electric motor are monitored. The electrical current is monitored directly without an intervening current prediction step. Interim voltage commands are determined based upon the initial current commands and the monitored currents, and final voltage commands are determined by subjecting the interim voltage commands to voltage limits. A rotational position compensation term is determined based upon the rotational position and rotational speed of the electric motor, and operation of the inverter is controlled to control the electric motor based upon the final voltage commands and the rotational position compensation term.
    Type: Grant
    Filed: November 14, 2017
    Date of Patent: June 25, 2019
    Assignee: GM Global Technology Operations LLC.
    Inventors: Lei Hao, Chandra S. Namuduri, Suresh Gopalakrishnan
  • Patent number: 10293805
    Abstract: A system includes an engine, a generator assembly, a direct current voltage bus, and a controller. The assembly is coupled to and driven via the engine, and has an electric generator, field windings, and a voltage rectifier collectively producing a generator output voltage. An inner control loop of the controller provides a field duty cycle signal to the field windings in response to an adjusted voltage control signal. An outer control loop of the controller provides a torque-based voltage control signal as an input to the inner control loop in response to a commanded engine torque and an estimated generator torque. An output torque of the generator is directly controlled via the outer control loop. The inner control loop calculates the adjusted voltage control signal as a difference between the torque-based voltage control signal and the output voltage.
    Type: Grant
    Filed: July 18, 2017
    Date of Patent: May 21, 2019
    Assignee: GM Global Technology Operations LLC.
    Inventors: Chandra S. Namuduri, Suresh Gopalakrishnan
  • Patent number: 10293804
    Abstract: A vehicle propulsion system includes an engine and a first electric machine each configured to selectively provide torque to propel the vehicle. The propulsion system also includes a second electric machine coupled to the engine and configured to start the engine from an inactive state. A high-voltage battery powers both of the first electric machine and the second electric machine over a high-voltage bus. The vehicle further includes a controller programmed to issue a command to start the engine using the second electric machine in response to a threshold acceleration demand following a period of reduced acceleration demand.
    Type: Grant
    Filed: May 19, 2016
    Date of Patent: May 21, 2019
    Assignee: GM Global Technology Operations LLC
    Inventors: Chandra S. Namuduri, Lei Hao, Suresh Gopalakrishnan, Thomas W. Nehl
  • Publication number: 20190145370
    Abstract: A starter for an internal combustion engine includes a multi-phase brushless electric motor, a controller and an inverter. A method for controlling the starter includes determining initial current commands for operating the electric motor in response to an activation command. Electrical current supplied to the electric motor and a rotational position of an output member of the electric motor are monitored. The electrical current is monitored directly without an intervening current prediction step. Interim voltage commands are determined based upon the initial current commands and the monitored currents, and final voltage commands are determined by subjecting the interim voltage commands to voltage limits. A rotational position compensation term is determined based upon the rotational position and rotational speed of the electric motor, and operation of the inverter is controlled to control the electric motor based upon the final voltage commands and the rotational position compensation term.
    Type: Application
    Filed: November 14, 2017
    Publication date: May 16, 2019
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Lei Hao, Chandra S. Namuduri, Suresh Gopalakrishnan
  • Patent number: 10259448
    Abstract: A hybrid vehicle propulsion includes an engine and a first electric machine, where each is configured to selectively provide torque to propel the vehicle. The propulsion system also includes a second electric machine coupled to the engine to provide torque to start the engine from an inactive state. A high-voltage power source is configured to power both of the first electric machine and the second electric machine over a high-voltage bus. The propulsion system further includes a controller programmed to deactivate the engine and propel the vehicle using the first electric machine in response to the vehicle being driven at a steady-state speed for a predetermined duration of time. The controller is also programmed to restart the engine using the second electric machine powered by the high-voltage power source.
    Type: Grant
    Filed: August 17, 2016
    Date of Patent: April 16, 2019
    Assignee: GM Global Technology Operations LLC
    Inventors: Norman K. Bucknor, Suresh Gopalakrishnan, Lei Hao, Derek F. Lahr, Dongxu Li, Shifang Li, Chandra S. Namuduri, Thomas W. Nehl, Avoki M. Omekanda, Rashmi Prasad, Farzad Samie, Aaron M. Sullivan
  • Publication number: 20190103797
    Abstract: A solenoid assembly includes a solenoid actuator having a core. A coil is configured to be wound at least partially around the core such that a magnetic flux (?) is generated when an electric current flows through the coil. An armature is configured to be movable based on the magnetic flux (?). A controller has a processor and tangible, non-transitory memory on which is recorded instructions for controlling the solenoid assembly. The controller is configured to obtain a plurality of model matrices, a coil current (i1) and an eddy current (i2). The magnetic flux (?) is obtained based at least partially on a third model matrix (C0), the coil current (i1) and the eddy current (i2). Operation of the solenoid actuator is controlled based at least partially on the magnetic flux (?). In one example, the solenoid actuator is an injector.
    Type: Application
    Filed: October 3, 2017
    Publication date: April 4, 2019
    Applicant: GM Global Technology Operations LLC
    Inventors: Shifang Li, Thomas W. Nehl, Suresh Gopalakrishnan, Avoki Omekanda, Rashmi Prasad, Chandra S. Namuduri
  • Patent number: 10227941
    Abstract: A vehicle propulsion system includes an internal combustion engine configured to output a primary output torque and at least one fuel injector arranged to supply fuel to a combustion chamber of the engine. The propulsion system also includes at least one exhaust aftertreatment device to capture combustion byproducts within an exhaust flow. The propulsion system also includes an electric machine coupled to the engine to exchange torque. A controller is programmed to supply a baseline fuel injection corresponding to a first engine output to satisfy a driver torque demand and to periodically supplement the baseline target fuel injection quantity to increase engine output torque to overshoot the first engine output thereby increasing combustion byproducts to regenerate the at least one exhaust aftertreatment device. The controller is also programmed to apply a resistive torque from the electric machine such that an overall propulsion system torque remains at the driver torque demand.
    Type: Grant
    Filed: May 1, 2017
    Date of Patent: March 12, 2019
    Assignee: GM Global Technology Operations LLC
    Inventors: Yue-Yun Wang, Venkata Prasad Atluri, Suresh Gopalakrishnan, Alberto Lorenzo Vassallo
  • Patent number: 10207699
    Abstract: A vehicle propulsion system includes a combustion engine configured to output a propulsion torque to satisfy a propulsion demand, and a traction electric machine to generate a supplemental torque to selectively supplement the propulsion torque. The propulsion system also includes a controller programmed to forecast an acceleration demand based on at least one estimation model. The controller is also programmed to issue a command indicative of a required axle torque corresponding to the acceleration demand. The controller is further programmed to engage at least one fuel conservation action in response to the required axle torque being within a first predetermined torque threshold range.
    Type: Grant
    Filed: October 2, 2017
    Date of Patent: February 19, 2019
    Inventors: Chandra S. Namuduri, Venkata Prasad Atluri, Suresh Gopalakrishnan, Jin-Woo Lee, Kevin J. Robinet, Sai Rajagopalan, Chen-fang Chang, Michael Livshiz, Patrick J. O'leary
  • Patent number: 10189469
    Abstract: A method of controlling a powertrain of a vehicle includes opening and/or closing one or more of a first switching device, a second switching device, a third switching device, and engaging and/or disengaging at least one of a pair of actuators for a starter mechanism or a motor/generator clutch. Many different control modes are provided for the powertrain by changing the operation of a motor-generator between a motor or a generator, and changing the electrical connections between a first energy storage device, a second energy storage device, an auxiliary electric system, the starter mechanism, and the motor-generator.
    Type: Grant
    Filed: March 20, 2015
    Date of Patent: January 29, 2019
    Assignee: GM Global Technology Operations LLC
    Inventors: Venkata Prasad Atluri, Suresh Gopalakrishnan, Michael G. Reynolds, Chandra S. Namuduri, Kenneth J. Shoemaker, David W. Walters
  • Patent number: 10190526
    Abstract: A method for providing consistent actuator events for each of a plurality of consecutive actuator events of an electromagnetic actuator, includes applying a first bi-directional current waveform for a first actuator event and applying a second bi-directional current waveform for a second actuator event immediately subsequent to the first actuator event. The first bi-directional current waveform includes applying current in a first direction when the actuator is commanded to an actuated position and applying current in a reversed second direction when the actuator is commanded to a rest position. The second bi-directional current waveform includes applying current in the reversed second direction when the actuator is commanded to an actuated position and applying current in the first direction when the actuator is commanded to a rest position.
    Type: Grant
    Filed: March 19, 2015
    Date of Patent: January 29, 2019
    Assignee: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Thomas W. Nehl, Suresh Gopalakrishnan, Avoki M. Omekanda, Chandra S. Namuduri
  • Publication number: 20190023255
    Abstract: A system includes an engine, a generator assembly, a direct current voltage bus, and a controller. The assembly is coupled to and driven via the engine, and has an electric generator, field windings, and a voltage rectifier collectively producing a generator output voltage. An inner control loop of the controller provides a field duty cycle signal to the field windings in response to an adjusted voltage control signal. An outer control loop of the controller provides a torque-based voltage control signal as an input to the inner control loop in response to a commanded engine torque and an estimated generator torque. An output torque of the generator is directly controlled via the outer control loop. The inner control loop calculates the adjusted voltage control signal as a difference between the torque-based voltage control signal and the output voltage.
    Type: Application
    Filed: July 18, 2017
    Publication date: January 24, 2019
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Chandra S. Namuduri, Suresh Gopalakrishnan
  • Patent number: 10133744
    Abstract: Methods, apparatuses, and systems directed to improving shared file access in wide area network file systems. In a particular implementation, one or more elements of a wide area file system cooperate to keep an original file intact on a remote file server until a new copy of the same file is completely flushed to the remote file server. In a particular implementation, rename operations identifying a source and a target in connection with application-level save operations are executed as two composite operations including creation of the target, and a delayed deletion of the source. The delay after which the source is deleted can be configured to be just large enough so that the application save operation on a local cache can be completed.
    Type: Grant
    Filed: August 25, 2015
    Date of Patent: November 20, 2018
    Assignee: SYMANTEC CORPORATION
    Inventors: Hrishikesh A. Vidwans, Suresh Gopalakrishnan, Shirish H. Phatak
  • Patent number: 10129119
    Abstract: An access data analytics system including a processor and a memory is provided. The processor stores an electronic report in the memory. The electronic report is generated based on an electronic report query include a plurality of parameters. The processor also collects access profile data including metadata associated with a user accessing the report, stores the access profile data within the memory, receives an access analytics data request requesting access analytics data associated with the stored report, retrieves the stored access profile data, generates an access analysis table including the access analytics data associated with the stored report based on the retrieved access profile data, and provides an extract including at least a portion of the access analytics data associated with the stored report from the access analysis table to a requestor of the access analytics data request.
    Type: Grant
    Filed: October 7, 2016
    Date of Patent: November 13, 2018
    Assignee: MASTERCARD INTERNATIONAL INCORPORATED
    Inventors: Suresh Gopalakrishnan, Kim J. Murphy, Probal Ghosh
  • Publication number: 20180313283
    Abstract: A vehicle propulsion system includes an internal combustion engine configured to output a primary output torque and at least one fuel injector arranged to supply fuel to a combustion chamber of the engine. The propulsion system also includes at least one exhaust aftertreatment device to capture combustion byproducts within an exhaust flow. The propulsion system also includes an electric machine coupled to the engine to exchange torque. A controller is programmed to supply a baseline fuel injection corresponding to a first engine output to satisfy a driver torque demand and to periodically supplement the baseline target fuel injection quantity to increase engine output torque to overshoot the first engine output thereby increasing combustion byproducts to regenerate the at least one exhaust aftertreatment device. The controller is also programmed to apply a resistive torque from the electric machine such that an overall propulsion system torque remains at the driver torque demand.
    Type: Application
    Filed: May 1, 2017
    Publication date: November 1, 2018
    Inventors: Yue-Yun WANG, Venkata Prasad ATLURI, Suresh GOPALAKRISHNAN, Alberto Lorenzo VASSALLO
  • Patent number: 10110103
    Abstract: An electric drive system includes bus rails carrying a bus voltage, an energy storage system (ESS), and a power inverter. The system includes a voltage converter connected to the bus rails and having an inductor coil, semiconductor switches, a bypass switch connected to a positive bus rail, and a capacitor. A polyphase electric machine is electrically connected to the power inverter. A controller executes a method in which operation of the converter is regulated based on power, torque, and speed values of the electric machine. The converter is selectively bypassed by closing the bypass switch under predetermined high-power/high-torque conditions, with the bus voltage adjusted until it is equal to the battery output voltage. The bypass switch is opened and the bus voltage thereafter regulated to a predetermined voltage.
    Type: Grant
    Filed: June 21, 2017
    Date of Patent: October 23, 2018
    Assignee: GM Global Technology Operations LLC
    Inventors: Lei Hao, Chandra S. Namuduri, Suresh Gopalakrishnan, Thomas W. Nehl
  • Patent number: 10101396
    Abstract: A machine control system and a method of detecting a current sensor malfunction include obtaining a first current signal from a first current sensor corresponding with a first phase of a multi-phase machine, obtaining a second current signal from a second current sensor corresponding with a second phase of the multi-phase machine, and obtaining a position signal indicating an angular position of a rotor of the multi-phase machine corresponding with values of the first current signal and the second current signal. A determination is made of whether the current sensor malfunction occurred in the first current sensor or the second current sensor based only on the values of the first current signal and the second current signal at four of the angular positions of the rotor.
    Type: Grant
    Filed: February 15, 2017
    Date of Patent: October 16, 2018
    Assignee: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Lei Hao, Chandra S. Namuduri, Suresh Gopalakrishnan