Patents by Inventor Mahesh M. Swamy

Mahesh M. Swamy 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: 20240178689
    Abstract: A power supply includes a first inverter and a second inverter. The second inverter is connected in series with the first inverter in an open delta configuration. The first inverter is configured to be powered by a first battery and to output a first power signal having a first phase angle. The second inverter is in electrical communication with the first inverter and configured to be powered by a second battery and to output a second power signal having a second phase angle. The power supply also includes a controller configured to control a phase difference between the first phase angle and the second phase angle to control a magnitude of a combined output voltage of the first inverter and the second inverter.
    Type: Application
    Filed: November 30, 2023
    Publication date: May 30, 2024
    Inventor: Mahesh M. Swamy
  • Publication number: 20240178763
    Abstract: A portable power supply may include an internal power source and a active front-end converter connected to the internal power source. The active front-end converter includes a positive DC connector lead, a negative DC connector lead, a positive source side lead, a negative source side lead, and a plurality of switches. The active front-end converter is configured to operate as a DC-DC converter for DC input signals and an AC-DC inverter for AC input signals. The portable power supply also includes an AC source input, and a DC source input.
    Type: Application
    Filed: November 30, 2023
    Publication date: May 30, 2024
    Inventor: Mahesh M. Swamy
  • Publication number: 20230395880
    Abstract: A power supply that includes a rectifier, a converter connected to the rectifier, a plurality of battery management system controllers, and a plurality of inverters. The plurality of battery management system controllers are connected to the converter and configured to connect to a plurality of battery packs. Each battery pack is configured to be connected to a dedicated battery management system controller. The plurality of inverters are configured to connect to the plurality of battery packs. Each inverter is configured to connect to one of the plurality of battery packs. A first inverter and a last inverter provide terminals configured to connect to a load. The cascade converter employs a charger that has a high frequency (“hf”) isolation transformer with multiple secondary windings with identical number of turns to cater to the charging requirements of multiple battery packs.
    Type: Application
    Filed: May 31, 2023
    Publication date: December 7, 2023
    Inventor: Mahesh M. Swamy
  • Patent number: 11404991
    Abstract: A voltage source inverter comprises a rectifier circuit having an input for connection to a multi-phase AC power source and converting the AC power to DC power and an inverter circuit for receiving DC power and converting the DC power to AC power. A DC bus circuit is connected between the rectifier circuit and the inverter circuit to provide a relatively fixed DC voltage for the inverter circuit, the DC bus circuit comprising a DC bus including a first bus rail comprising an inductor and a second bus rail, and a soft charge circuit connected in series with a DC bus capacitor network between the first and second rails, the DC bus capacitor network comprising a first capacitor branch including a pair of capacitors with a fuse connected in series between the capacitors, a balancing resistor across each capacitor and a snubbing capacitor connected across the fuse.
    Type: Grant
    Filed: January 7, 2021
    Date of Patent: August 2, 2022
    Assignee: Yaskawa America, Inc.
    Inventors: Mahesh M. Swamy, Nathan T. Seipel
  • Publication number: 20220200303
    Abstract: A portable power supply including an internal power source, an AC output, a DC output, and an input unit configured to receive power from a first external source. The portable power supply further includes a first power conversion unit configured to convert the power received from the first external source to a first DC power used for charging the internal power source, an AC power conversion unit configured to convert power output by the internal power source to an AC power used for powering a first peripheral device connected to the AC output, and a DC power conversion unit configured to convert power output by the internal power source to a second DC power used for powering a second peripheral device connected to the DC output.
    Type: Application
    Filed: December 17, 2021
    Publication date: June 23, 2022
    Inventors: Mahesh M. Swamy, Omid H. Shirazi, Matthew R. Polakowski, Nathan J. Gustafson, Chien-Chih Chao, Samantha L. Billetdeaux, Michael R. Halverson, Benjamin C. Tesch, Chun Jian Tang, Michael A. Matthews, James Dykstra, Brian M. Hockers, Catherine Kelli Semon, Andrew S. Lentz
  • Publication number: 20210218359
    Abstract: A voltage source inverter comprises a rectifier circuit having an input for connection to a multi-phase AC power source and converting the AC power to DC power and an inverter circuit for receiving DC power and converting the DC power to AC power. A DC bus circuit is connected between the rectifier circuit and the inverter circuit to provide a relatively fixed DC voltage for the inverter circuit, the DC bus circuit comprising a DC bus including a first bus rail comprising an inductor and a second bus rail, and a soft charge circuit connected in series with a DC bus capacitor network between the first and second rails, the DC bus capacitor network comprising a first capacitor branch including a pair of capacitors with a fuse connected in series between the capacitors, a balancing resistor across each capacitor and a snubbing capacitor connected across the fuse.
    Type: Application
    Filed: January 7, 2021
    Publication date: July 15, 2021
    Inventors: Mahesh M. Swamy, Nathan T. Seipel
  • Publication number: 20190190383
    Abstract: An inductorless DC to DC converter comprises an input for connection to a DC supply and an output for connection to a DC load. A first capacitor is connected across one of the input and the output. A plurality of second capacitors are connected in series across the other of the input and the output. The first capacitor and the second capacitors are of equal capacitance. A plurality of switch circuits are provided, one for each second capacitor. Each switch circuit is connected across the first capacitor and one of the second capacitors. A control circuit controls operation of the plurality of switch circuits to momentarily place each second capacitor alternately across the first capacitor to transfer voltage therebetween to selectively step-down or step-up voltage of the DC supply to the DC load.
    Type: Application
    Filed: February 22, 2019
    Publication date: June 20, 2019
    Applicant: Yaskawa America, Inc.
    Inventor: Mahesh M. Swamy
  • Publication number: 20190190382
    Abstract: An inductorless DC to DC converter comprises an input for connection to a DC supply and an output for connection to a DC load. A first capacitor is connected across one of the input and the output. A plurality of second capacitors are connected in series across the other of the input and the output. The first capacitor and the second capacitors are of equal capacitance. A plurality of switch circuits are provided, one for each second capacitor. Each switch circuit is connected across the first capacitor and one of the second capacitors. A control circuit controls operation of the plurality of switch circuits to momentarily place each second capacitor alternately across the first capacitor to transfer voltage therebetween to selectively step-down or step-up voltage of the DC supply to the DC load.
    Type: Application
    Filed: February 22, 2019
    Publication date: June 20, 2019
    Applicant: Yaskawa America, Inc.
    Inventor: Mahesh M. SWAMY
  • Publication number: 20190181755
    Abstract: An inductorless DC to DC converter comprises an input for connection to a DC supply and an output for connection to a DC load. A first capacitor is connected across one of the input and the output. A plurality of second capacitors are connected in series across the other of the input and the output. The first capacitor and the second capacitors are of equal capacitance. A plurality of switch circuits are provided, one for each second capacitor. Each switch circuit is connected across the first capacitor and one of the second capacitors. A control circuit controls operation of the plurality of switch circuits to momentarily place each second capacitor alternately across the first capacitor to transfer energy therebetween to selectively step-down or step-up voltage of the DC supply to the DC load.
    Type: Application
    Filed: August 1, 2018
    Publication date: June 13, 2019
    Inventor: Mahesh M. Swamy
  • Patent number: 10088517
    Abstract: A motor drive system output filter includes fault detection. A variable frequency drive (VFD) drives a three phase AC induction motor. A filter circuit is connected between the VFD and the AC induction motor. The filter circuit comprises a filter for each phase. Each filter comprises an inductor and a damping resistor connected in series with a blocking capacitor across the inductor. A plurality of detection circuits are provided, one for each phase. Each detection circuit is connected to the capacitor of the associated phase for detecting capacitor voltage to indicate a resistor fault condition.
    Type: Grant
    Filed: October 7, 2016
    Date of Patent: October 2, 2018
    Assignee: Yaskawa America, Inc.
    Inventors: Mahesh M. Swamy, Mark Baumgardner, Steven Hartig, Daniel Nitzsche
  • Patent number: 10063179
    Abstract: As described herein, a drive circuit for a three phase AC motor comprises an AC/AC converter. The converter has an input for receiving multiphase AC power from an AC source and converting the AC power to variable voltage and variable frequency from the AC source for driving the AC motor. A filter circuit is connected to the AC/AC converter and comprises at least one inductor per phase and at least one capacitor per phase. The capacitors are connected in a broken wye configuration with one side connected to one of the inductors and an opposite side connected via a three phase diode bridge rectifier to a switch. The switch is controlled by a converter control to selectively open or short a neutral point of the broken wye capacitor configuration.
    Type: Grant
    Filed: November 30, 2015
    Date of Patent: August 28, 2018
    Assignee: Yaskawa America, Inc.
    Inventor: Mahesh M. Swamy
  • Publication number: 20180100889
    Abstract: A motor drive system output filter includes fault detection. A variable frequency drive (VFD) drives a three phase AC induction motor. A filter circuit is connected between the VFD and the AC induction motor. The filter circuit comprises a filter for each phase. Each filter comprises an inductor and a damping resistor connected in series with a blocking capacitor across the inductor. A plurality of detection circuits are provided, one for each phase. Each detection circuit is connected to the capacitor of the associated phase for detecting capacitor voltage to indicate a resistor fault condition.
    Type: Application
    Filed: October 7, 2016
    Publication date: April 12, 2018
    Inventors: Mahesh M. Swamy, Mark Baumgardner, Steven Hartig, Daniel Nitzsche
  • Patent number: 9853587
    Abstract: A variable frequency motor drive comprises a converter including a rectifier having an input for connection to an AC power source and converting the AC power to DC power. A DC bus is connected to the rectifier circuit. At least one bus capacitor is across the DC bus. An inverter receives DC power from the DC bus and converts the DC power to AC power to drive a motor. A controller is operatively connected to the converter. The controller comprises a speed control controlling the inverter responsive to a speed command to maintain a desired motor speed. A speed foldback control measures DC bus ripple voltage and regulates the speed command responsive to the measured DC bus ripple voltage.
    Type: Grant
    Filed: April 23, 2014
    Date of Patent: December 26, 2017
    Assignee: Yaskawa America, Inc.
    Inventors: Mahesh M. Swamy, Anupama Balakrishnan, Joshua David Collins
  • Patent number: 9318992
    Abstract: As described herein, a drive circuit for a three phase AC motor comprises an AC/AC converter. The converter has an input for receiving multiphase AC power from an AC source and converting the AC power to variable voltage and variable frequency from the AC source for driving the AC motor. A filter circuit is connected to the AC/AC converter and comprises at least one inductor per phase and at least one capacitor per phase. The capacitors are connected in a broken wye configuration with one side connected to one of the inductors and an opposite side connected via a three phase diode bridge rectifier to a switch. The switch is controlled by a converter control to selectively open or short a neutral point of the broken wye capacitor configuration.
    Type: Grant
    Filed: August 22, 2013
    Date of Patent: April 19, 2016
    Assignee: Yaskawa America, Inc.
    Inventor: Mahesh M. Swamy
  • Publication number: 20160079905
    Abstract: As described herein, a drive circuit for a three phase AC motor comprises an AC/AC converter. The converter has an input for receiving multiphase AC power from an AC source and converting the AC power to variable voltage and variable frequency from the AC source for driving the AC motor. A filter circuit is connected to the AC/AC converter and comprises at least one inductor per phase and at least one capacitor per phase. The capacitors are connected in a broken wye configuration with one side connected to one of the inductors and an opposite side connected via a three phase diode bridge rectifier to a switch. The switch is controlled by a converter control to selectively open or short a neutral point of the broken wye capacitor configuration.
    Type: Application
    Filed: November 30, 2015
    Publication date: March 17, 2016
    Inventor: Mahesh M. SWAMY
  • Publication number: 20150311853
    Abstract: A variable frequency motor drive comprises a converter including a rectifier having an input for connection to an AC power source and converting the AC power to DC power. A DC bus is connected to the rectifier circuit. At least one bus capacitor is across the DC bus. An inverter receives DC power from the DC bus and converts the DC power to AC power to drive a motor. A controller is operatively connected to the converter. The controller comprises a speed control controlling the inverter responsive to a speed command to maintain a desired motor speed. A speed foldback control measures DC bus ripple voltage and regulates the speed command responsive to the measured DC bus ripple voltage.
    Type: Application
    Filed: April 23, 2014
    Publication date: October 29, 2015
    Applicant: Yaskawa America, Inc.
    Inventors: Mahesh M. Swamy, Anupama Balakrishnan, Joshua David Collins
  • Patent number: 9154048
    Abstract: An AC/DC converter system comprises an input circuit for connection to a three-phase AC source. An isolation transformer comprises a symmetrical core with a set of primary windings and first and second sets of secondary windings wound on the symmetrical core providing balanced flux in all three phases and magnetically coupling to the set of primary windings. The first and second sets of secondary windings are phase shifted by select amounts from the set of primary windings. The set of primary windings is connected to the input circuit. An AC/DC converter comprises first, second and third three-phase rectifiers, the first three-phase rectifier is powered by the first set of secondary windings, the second three-phase rectifier is powered by the second set of secondary windings, and the third three-phase rectifier is powered by the input circuit. An output circuit is connected between the AC/DC converter and a DC load.
    Type: Grant
    Filed: April 23, 2013
    Date of Patent: October 6, 2015
    Assignee: Yaskawa America, Inc.
    Inventor: Mahesh M. Swamy
  • Publication number: 20150222199
    Abstract: A voltage source inverter comprises a rectifier having an input for receiving single-phase AC power from an AC source and converting the AC power to DC power on a DC bus. The DC bus has first and second rails to provide a relatively fixed DC voltage. A DC bus capacitor is across the first and second rails to smooth voltage ripple. An inverter receives DC power from the DC bus and converts the DC power to AC power. An active front end circuit comprises a pair of filter capacitors in series across the first and second rails to create a midpoint. A bidirectional switch is connected between the rectifier input and the midpoint. The bidirectional switch is controlled to inject current into the midpoint of the DC bus.
    Type: Application
    Filed: March 30, 2015
    Publication date: August 6, 2015
    Inventor: Mahesh M. Swamy
  • Patent number: 9099935
    Abstract: A voltage source inverter comprises a rectifier having an input for receiving single-phase AC power from an AC source and converting the AC power to DC power on a DC bus. The DC bus has first and second rails to provide a relatively fixed DC voltage. A DC bus capacitor is across the first and second rails to smooth voltage ripple. An inverter receives DC power from the DC bus and converts the DC power to AC power. An active front end circuit comprises a pair of filter capacitors in series across the first and second rails to create a midpoint. A bidirectional switch is connected between the rectifier input and the midpoint. The bidirectional switch is controlled to inject current into the midpoint of the DC bus.
    Type: Grant
    Filed: January 14, 2013
    Date of Patent: August 4, 2015
    Assignee: Yaskawa America, Inc.
    Inventor: Mahesh M. Swamy
  • Patent number: 9099934
    Abstract: A voltage source inverter comprises a rectifier converting AC power to DC power at an output. An inverter receives DC power and converts the DC power to AC power. A link circuit is connected between the rectifier circuit and the inverter circuit and comprises a DC bus. A DC bus capacitor across the DC bus smoothes voltage ripple. An active filter circuit comprises a pair of filter capacitors in series across the first and second rails to create a midpoint. Bidirectional switches are connected between the rectifier input and the midpoint. A current sensor is connected between the bidirectional switches and the midpoint. An active switch controller controls a conduction angle of the bidirectional switches to maintain DC bus voltage at a desired reference level under a wide load range.
    Type: Grant
    Filed: January 10, 2012
    Date of Patent: August 4, 2015
    Assignee: Yaskawa America, Inc.
    Inventor: Mahesh M. Swamy