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).
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Publication number: 20230395880Abstract: 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: ApplicationFiled: May 31, 2023Publication date: December 7, 2023Inventor: Mahesh M. Swamy
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Patent number: 11404991Abstract: 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: GrantFiled: January 7, 2021Date of Patent: August 2, 2022Assignee: Yaskawa America, Inc.Inventors: Mahesh M. Swamy, Nathan T. Seipel
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Publication number: 20220200303Abstract: 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: ApplicationFiled: December 17, 2021Publication date: June 23, 2022Inventors: 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
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Publication number: 20210218359Abstract: 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: ApplicationFiled: January 7, 2021Publication date: July 15, 2021Inventors: Mahesh M. Swamy, Nathan T. Seipel
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Publication number: 20190190383Abstract: 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: ApplicationFiled: February 22, 2019Publication date: June 20, 2019Applicant: Yaskawa America, Inc.Inventor: Mahesh M. Swamy
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Publication number: 20190190382Abstract: 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: ApplicationFiled: February 22, 2019Publication date: June 20, 2019Applicant: Yaskawa America, Inc.Inventor: Mahesh M. SWAMY
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Publication number: 20190181755Abstract: 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: ApplicationFiled: August 1, 2018Publication date: June 13, 2019Inventor: Mahesh M. Swamy
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Patent number: 10088517Abstract: 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: GrantFiled: October 7, 2016Date of Patent: October 2, 2018Assignee: Yaskawa America, Inc.Inventors: Mahesh M. Swamy, Mark Baumgardner, Steven Hartig, Daniel Nitzsche
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Patent number: 10063179Abstract: 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: GrantFiled: November 30, 2015Date of Patent: August 28, 2018Assignee: Yaskawa America, Inc.Inventor: Mahesh M. Swamy
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Publication number: 20180100889Abstract: 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: ApplicationFiled: October 7, 2016Publication date: April 12, 2018Inventors: Mahesh M. Swamy, Mark Baumgardner, Steven Hartig, Daniel Nitzsche
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Patent number: 9853587Abstract: 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: GrantFiled: April 23, 2014Date of Patent: December 26, 2017Assignee: Yaskawa America, Inc.Inventors: Mahesh M. Swamy, Anupama Balakrishnan, Joshua David Collins
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Patent number: 9318992Abstract: 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: GrantFiled: August 22, 2013Date of Patent: April 19, 2016Assignee: Yaskawa America, Inc.Inventor: Mahesh M. Swamy
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Publication number: 20160079905Abstract: 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: ApplicationFiled: November 30, 2015Publication date: March 17, 2016Inventor: Mahesh M. SWAMY
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Publication number: 20150311853Abstract: 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: ApplicationFiled: April 23, 2014Publication date: October 29, 2015Applicant: Yaskawa America, Inc.Inventors: Mahesh M. Swamy, Anupama Balakrishnan, Joshua David Collins
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Patent number: 9154048Abstract: 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: GrantFiled: April 23, 2013Date of Patent: October 6, 2015Assignee: Yaskawa America, Inc.Inventor: Mahesh M. Swamy
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Publication number: 20150222199Abstract: 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: ApplicationFiled: March 30, 2015Publication date: August 6, 2015Inventor: Mahesh M. Swamy
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Patent number: 9099935Abstract: 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: GrantFiled: January 14, 2013Date of Patent: August 4, 2015Assignee: Yaskawa America, Inc.Inventor: Mahesh M. Swamy
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Patent number: 9099934Abstract: 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: GrantFiled: January 10, 2012Date of Patent: August 4, 2015Assignee: Yaskawa America, Inc.Inventor: Mahesh M. Swamy
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Publication number: 20150054443Abstract: 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: ApplicationFiled: August 22, 2013Publication date: February 26, 2015Applicant: Yaskawa America, Inc.Inventor: Mahesh M. Swamy
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Publication number: 20140313800Abstract: 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: ApplicationFiled: April 23, 2013Publication date: October 23, 2014Applicant: Yaskawa America, Inc.Inventor: Mahesh M. Swamy