Patents by Inventor Shashank Krishnamurthy
Shashank Krishnamurthy 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).
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Patent number: 11866295Abstract: An elevator system control system is provided and includes a sensor system configured to sense elevator car conditions, a safety system signaling element to generate a safety signal indicative of an incident and a control system configured to react to the safety system signal. When the control system receives the safety signal indicating that an incident has occurred that requires engagement of at least one of primary and secondary brakes, the control system controls a deceleration rate during the incident by operating the primary brake, determining whether the deceleration rate is within a target range and adjusting the deceleration rate based on signals from the sensor system.Type: GrantFiled: August 20, 2018Date of Patent: January 9, 2024Assignee: OTIS ELEVATOR COMPANYInventors: Prasanna Nagarajan, David Ginsberg, Shashank Krishnamurthy, Daryl J. Marvin, Ronnie E. Thebeau
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Patent number: 11296623Abstract: A system includes a converter operatively connected to an alternating current (AC) power source and a direct current (DC) bus, an inverter operatively connected to a motor and the DC bus, and a controller. The converter includes a first plurality of switching devices in selective communication with each phase of the AC power source and the DC bus. The inverter includes a second plurality of switching devices in selective communication with each phase of a plurality of phases of the motor and the DC bus. The controller is operable to command dropping of a brake through a passive delay circuit responsive to detection of an emergency stop condition for a load driven by the motor and reduce a voltage on the DC bus by dropping at least one phase of the AC power source and/or using a dynamic braking resistor prior to the brake physically dropping.Type: GrantFiled: April 30, 2020Date of Patent: April 5, 2022Assignee: OTIS ELEVATOR COMPANYInventors: Prasanna Nagarajan, Shashank Krishnamurthy, Konda Reddy Chevva
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Patent number: 10934130Abstract: An elevator system includes a first elevator car (28) constructed and arranged to move in a first lane (30, 32, 34) and a first propulsion system (40) constructed and arranged to propel the first elevator. An electronic processor of the elevator system is configured to selectively control power delivered to the first propulsion system (40). The electronic processor includes a software-based power estimator configured to receive a first weight signal and a nm trajectory signal for calculating a power estimate and comparing the power estimate to a maximum power allowance. The electronic processor is configured to output an automated command signal if the power estimate exceeds the maximum power allowance.Type: GrantFiled: August 24, 2016Date of Patent: March 2, 2021Assignee: OTIS ELEVATOR COMPANYInventors: Shashank Krishnamurthy, Jose Miguel Pasini, David Ginsberg, Arthur Hsu
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Patent number: 10934131Abstract: A ropeless elevator system 10 includes a lane 13, 15, 17. One or more cars 20 are arranged in the lane. At least one linear motor 38, 40 is arranged along one of the lane and the one or more cars, and a magnet 50, 60 is arranged along the other of the lane and the one or more cars. The at least one magnet is responsive to the at least one linear motor. A linear motor controller 70 is operatively connected to the at least one linear motor, and a lane controller 80 is operatively connected to the linear motor controller. A back electro-motive force (EMF) module 84 is operatively connected to at least one of the linear motor controller and the lane controller. The lane controller being configured and disposed to control stopping one of the one or more cars based on a back EMF signal from the at least one linear motor determined by the EMF module.Type: GrantFiled: February 4, 2016Date of Patent: March 2, 2021Assignee: OTIS ELEVATOR COMPANYInventors: Shashank Krishnamurthy, Vladimir Blasko, Enrico Manes
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Patent number: 10919732Abstract: A transport system in a structure includes a car and a plurality of motor modules. The car is constructed and arranged to move along a lane generally defined at least in-part by the structure. The plurality of motor modules are distributed along the lane and are constructed and arranged to propel the car. Each one of the pluralities of motor modules include an embedded power module.Type: GrantFiled: May 28, 2019Date of Patent: February 16, 2021Assignee: OTIS ELEVATOR COMPANYInventor: Shashank Krishnamurthy
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Patent number: 10787340Abstract: A method of operating an elevator system for a learn run sequence including the steps of moving, using a linear propulsion system, an elevator car through a lane of an elevator shaft at a selected velocity; detecting, using a sensor system, the location of the elevator car when it moves through the lane; controlling, using a control system, the elevator car, the control system being in operable communication with the elevator car, the linear propulsion system, and the sensor system; and determining, using the control system, a location of each of the car state sensors relative to each other within the lane in response to at least one of a travel time of the elevator car, a velocity of the elevator car, a position of the elevator car, and a height of the elevator car.Type: GrantFiled: June 12, 2017Date of Patent: September 29, 2020Assignee: OTIS ELEVATOR COMPANYInventors: David Ginsberg, Shashank Krishnamurthy, Lei Xing, Penghe Geng, Ankit Anand Gupta, Yogesh Parmod Jadhav, Basavanagouda Goudra, Pramod Mandikal Gurukumar
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Patent number: 10773922Abstract: A drive and motor system and method for a six phase machine with negligible common-mode voltage is provided. The six-phase machine includes six phase windings divided into at least two windings groups configured to generate a zero common-mode pulse width modulation. The drive and motor system and method can also include at least one direct current source and a six phase inverter switching between positive and negative power of the at least one direct current source.Type: GrantFiled: February 3, 2016Date of Patent: September 15, 2020Assignee: OTIS ELEVATOR COMPANYInventors: Dong Jiang, Shashank Krishnamurthy, Daryl J. Marvin
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Patent number: 10745238Abstract: An elevator power distribution system includes an elevator car (114; 214; 314; 414; 514) configured to travel in a lane (113, 115, 117; 213; 313, 315, 317; 413, 415, 417; 513, 515, 517) of an elevator shaft (111) and a linear propulsion system configured to impart force to the elevator car. The linear propulsion system includes a first portion (216), mounted in the lane and a second portion (218) mounted to the elevator car configured to coact with the first portion (216) to impart movement to the elevator car.Type: GrantFiled: January 19, 2016Date of Patent: August 18, 2020Assignee: OTIS ELEVATOR COMPANYInventors: Shashank Krishnamurthy, Daryl J. Marvin, Luis Arnedo
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Publication number: 20200259430Abstract: A system includes a converter operatively connected to an alternating current (AC) power source and a direct current (DC) bus, an inverter operatively connected to a motor and the DC bus, and a controller. The converter includes a first plurality of switching devices in selective communication with each phase of the AC power source and the DC bus. The inverter includes a second plurality of switching devices in selective communication with each phase of a plurality of phases of the motor and the DC bus. The controller is operable to command dropping of a brake through a passive delay circuit responsive to detection of an emergency stop condition for a load driven by the motor and reduce a voltage on the DC bus by dropping at least one phase of the AC power source and/or using a dynamic braking resistor prior to the brake physically dropping.Type: ApplicationFiled: April 30, 2020Publication date: August 13, 2020Inventors: Prasanna Nagarajan, Shashank Krishnamurthy, Konda Reddy Chevva
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Patent number: 10689226Abstract: An elevator car travels in a lane (113, 115, 117) of an elevator shaft (111). A linear propulsion system imparts force to the car (214). The system includes a first part (116) mounted in the lane of the shaft and a second part (118) mounted to the elevator car configured to co-act with the first part to impart movement to the car. Car state sensors (360a-c) are disposed in the lane and determine a state space vector of the car within the lane. A sensed element (364) on the car is sensed by the plurality of car state sensors when the car is in proximity to the respective car state sensor. A control system (225) applies an electrical current to at least one of the first part and the second part and the plurality of car state sensors communicate with the control system and the linear propulsion system to provide state space vector data.Type: GrantFiled: February 3, 2016Date of Patent: June 23, 2020Assignee: OTIS ELEVATOR COMPANYInventors: Peter DePaola, Jr., Richard N. Fargo, David Ginsberg, Dang V. Nguyen, Shashank Krishnamurthy
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Patent number: 10680538Abstract: A system includes a converter operatively connected to an alternating current (AC) power source and a direct current (DC) bus, an inverter operatively connected to a motor and the DC bus, and a controller. The converter includes a first plurality of switching devices in selective communication with each phase of the AC power source and the DC bus. The inverter includes a second plurality of switching devices in selective communication with each phase of the motor and the DC bus. The controller is operable to command dropping of a brake through a passive delay circuit responsive to an emergency stop condition for a load driven by the motor and reduce a voltage on the DC bus by dropping at least one phase of the AC power source and/or using a dynamic braking resistor prior to the brake physically dropping.Type: GrantFiled: September 28, 2017Date of Patent: June 9, 2020Assignee: OTIS ELEVATOR COMPANYInventors: Prasanna Nagarajan, Shashank Krishnamurthy, Konda Reddy Chevva
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Patent number: 10647543Abstract: An elevator system with an elevator car 14, a linear propulsion system to impart force to the elevator car in a hoistway 11, a hoistway communication network 106, 206, a local communication network 110, 210, 310 and motion controls. One of the motion controls proximate to the elevator car is designated as a primary control 61 operable to command at least one drive 42A-42F via the local communication network. The at least one drive is coupled to one or more motor segments 22 of the linear propulsion system. The elevator system further includes a controller 46 operable to command the primary control via the hoistway communication network to reposition the elevator car within the hoistway. The designation of the primary control transitions between the motion controls as the elevator car moves in the hoistway.Type: GrantFiled: February 4, 2016Date of Patent: May 12, 2020Assignee: OTIS ELEVATOR COMPANYInventors: David Ginsberg, Dang V. Nguyen, Shashank Krishnamurthy
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Publication number: 20200055693Abstract: An elevator system control system is provided and includes a sensor system configured to sense elevator car conditions, a safety system signaling element to generate a safety signal indicative of an incident and a control system configured to react to the safety system signal. When the control system receives the safety signal indicating that an incident has occurred that requires engagement of at least one of primary and secondary brakes, the control system controls a deceleration rate during the incident by operating the primary brake, determining whether the deceleration rate is within a target range and adjusting the deceleration rate based on signals from the sensor system.Type: ApplicationFiled: August 20, 2018Publication date: February 20, 2020Inventors: Prasanna Nagarajan, David Ginsberg, Shashank Krishnamurthy, Daryl J. Marvin, Ronnie E. Thebeau
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Patent number: 10513413Abstract: A method (70) for controlling a multilevel regenerative drive (30) having a converter (32) and an inverter (34) is disclosed. The method (70) may include applying at least one of unipolar modulation and bipolar modulation to the converter (32), and applying at least one of unipolar modulation and bipolar modulation to the inverter (34). A control system (52) for a mechanical system (20) having a motor (28) is also disclosed. The control system (52) may comprise a converter (32) operatively connected to a power source (29), and an inverter (34) operatively connected to the motor (28) of the mechanical system (20). At least one controller may be in communication with the converter (32) and inverter (34), and may be configured to apply at least one of unipolar modulation and bipolar modulation to each of the converter (32) and the inverter (34).Type: GrantFiled: December 18, 2013Date of Patent: December 24, 2019Assignee: OTIS ELEVATOR COMPANYInventors: Ismail Agirman, Shashank Krishnamurthy, Prasanna Nagarajan, Hanjong Kim, Yang Wang
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Patent number: 10513414Abstract: A system including a drive portion, and an external computing device in communication with the drive portion, wherein the external computing device is configured to receive operational data from the drive portion, determine operational parameters based at least in part on the operational data, determine whether the operational parameters are valid, and automatically transmit commands to the drive portion if the operational parameters are valid.Type: GrantFiled: December 17, 2015Date of Patent: December 24, 2019Assignee: OTIS ELEVATOR COMPANYInventors: Yang Wang, HanJong Kim, Christopher S. Czerwinski, Edward Piedra, Shashank Krishnamurthy, Draguna Vrabie, Rui Huang
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Patent number: 10427908Abstract: An elevator system and/or method executed by an elevator controller for detecting a fault within the elevator system. The elevator controller utilizes the fault to disable a drive control portion of the elevator controller and activate a drive u-stop control portion of the elevator controller. The drive u-stop control portion of the elevator controller generates a signal based on at least one of a speed estimation, a velocity profile, and feedforward information. The elevator controller applies the signal to an inverter connected to the elevator controller to execute the urgent stop of an elevator car of the elevator system.Type: GrantFiled: April 15, 2016Date of Patent: October 1, 2019Assignee: OTIS ELEVATOR COMPANYInventors: Shashank Krishnamurthy, Daryl J. Marvin
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Publication number: 20190276278Abstract: A transport system in a structure includes a car and a plurality of motor modules. The car is constructed and arranged to move along a lane generally defined at least in-part by the structure. The plurality of motor modules are distributed along the lane and are constructed and arranged to propel the car. Each one of the pluralities of motor modules include an embedded power module.Type: ApplicationFiled: May 28, 2019Publication date: September 12, 2019Inventor: Shashank Krishnamurthy
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Patent number: 10407273Abstract: An elevator control system is configured to control an elevator car constructed and arranged to move along a hoistway defined by a stationary structure. The elevator system may include a communication pathway and a hoistway control system supported by the stationary structure and configured to send a continuous brake command signal over the pathway. A car control system is carried by the elevator car and is configured to receive the continuous brake command signal and initiate a brake Ustop mode upon a loss of the brake command signal, and independent of the hoistway control system.Type: GrantFiled: September 15, 2016Date of Patent: September 10, 2019Assignee: OTIS ELEVATOR COMPANYInventors: David Ginsberg, Xiaodong Luo, Shashank Krishnamurthy, Dang V. Nguyen, Richard Fargo
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Patent number: 10381952Abstract: A method of configuring a power conversion cell for a distributed power system according to an example of the present disclosure includes: importing one or more software modules onto a controller of a conversion device configured to control power conversion with one or more of the modules selected based on one or more of a load or source device, and the results of a software simulation.Type: GrantFiled: October 2, 2015Date of Patent: August 13, 2019Assignee: United Technologies CorporationInventors: Luis Arnedo, Shashank Krishnamurthy, Vladimir Blasko
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Patent number: 10366935Abstract: A drive unit for a motor includes a printed circuit board (PCB); a first gallium nitride switch having a gate, the first gallium nitride switch mounted to the PCB; a second gallium nitride switch having a gate, the second gallium nitride switch mounted to the PCB; a gate driver generating a turn-off drive signal to turn off the first gallium nitride switch and turn off the second gallium nitride switch; a first turn-off trace on the PCB, the first turn-off trace directing the turn-off drive signal to the gate of the first gallium nitride switch; and a second turn-off trace on the PCB, the second turn-off trace directing the turn-off drive signal to the gate of the second gallium nitride switch; wherein an impedance of the first turn-off trace is substantially equal to an impedance of the second turn-off trace.Type: GrantFiled: April 9, 2013Date of Patent: July 30, 2019Assignee: OTIS ELEVATOR COMPANYInventors: Shashank Krishnamurthy, Xin Wu, William A. Veronesi, Kyle W. Rogers, Daryl J. Marvin