Patents by Inventor John Dhyanchand
John Dhyanchand 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: 6462429Abstract: A generator/starter system for starting an engine and for tapping power from the engine in order to generate electricity includes a squirrel cage rotor, a main stator winding, an auxiliary stator winding, and an excitation source. The main stator winding is magnetically coupled to the squirrel cage rotor so as to provide an AC output in response to rotation of the squirrel cage rotor and so as to rotate the squirrel cage rotor in response to an AC input. The auxiliary stator winding is magnetically coupled to the squirrel cage rotor so as to provide excitation current when the main stator winding is providing the AC output. The source of excitation current is coupled to the auxiliary stator winding.Type: GrantFiled: February 24, 2000Date of Patent: October 8, 2002Assignee: Hamilton Sundstrand CorporationInventors: John Dhyanchand, Donald G. Fair, Chai-Nam Ng
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Publication number: 20020047455Abstract: A generator/starter system for starting an engine and for tapping power from the engine in order to generate electricity includes a squirrel cage rotor, a main stator winding, an auxiliary stator winding, and an excitation source. The main stator winding is magnetically coupled to the squirrel cage rotor so as to provide an AC output in response to rotation of the squirrel cage rotor and so as to rotate the squirrel cage rotor in response to an AC input. The auxiliary stator winding is magnetically coupled to the squirrel cage rotor so as to provide excitation current when the main stator winding is providing the AC output. The source of excitation current is coupled to the auxiliary stator winding.Type: ApplicationFiled: May 15, 2001Publication date: April 25, 2002Applicant: Hamilton Sundstrand CorporationInventors: John Dhyanchand, Donald G. Fair, Chai-Nam Ng
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Patent number: 5666278Abstract: An inverter includes first and second subinverters each having inputs connected in series with the input of the other subinverter across a DC voltage and each further having a switch coupled to an output. A summing circuit includes a first input coupled to the output of the first subinverter, a second input coupled to the output of second inverter and an output. A control circuit is coupled to the subinverters and operates the switches such that a summed AC waveform is produced at the output of the summing circuit. Each switch is subjected to only a portion of the DC voltage.Type: GrantFiled: September 1, 1994Date of Patent: September 9, 1997Assignee: Sundstrand CorporationInventors: Chai-Nam Ng, P. John Dhyanchand, Vietson M. Nguyen
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Patent number: 5657214Abstract: An inverter for converting DC power into AC power includes first and second subinverters having a plurality of controllable switches and three-phase outputs coupled to a summing transformer having wye and delta connected sets of primary windings and a set of secondary windings. The switches in the subinverters are controlled so that the subinverters produce first and second sets of pulse-width modulated subinverter waveforms which are summed by the summing transformer to produce the AC power in the secondary winding.Type: GrantFiled: June 3, 1991Date of Patent: August 12, 1997Assignee: Sundstrand CorporationInventors: Vietson Nguyen, P. John Dhyanchand
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Patent number: 5600548Abstract: A control for an inverter having a switch which is operated in accordance with a PWM waveform having spaced rising and falling edges includes circuitry which detects the magnitude and polarity of a DC component in the AC output power produced by the inverter and an adder/subtractor which adjusts at least one of a rising and falling edge of the waveform to reduce the magnitude of the DC component.Type: GrantFiled: August 11, 1994Date of Patent: February 4, 1997Assignee: Sundstrand CorporationInventors: Vietson Nguyen, P. John Dhyanchand
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Patent number: 5559686Abstract: A stepped waveform inverter and control therefor utilizes the inverter itself as a divide-by-N counter in a phase-locked loop to assure precise control over the output phase and frequency of the inverter.Type: GrantFiled: July 8, 1994Date of Patent: September 24, 1996Assignee: Sundstrand CorporationInventors: Sunil Patel, Chai-Nam Ng, P. John Dhyanchand, Vietson M. Nguyen, Michael Teagardin
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Patent number: 5495403Abstract: A summing transformer includes first and second sets of primary windings and first and second sets of secondary windings. The primary windings of the first set are connected in a wye configuration whereas the windings of the second set are connected in a delta configuration and the sets of primary windings are connected to form a wye-delta configuration having terminals coupled to the outputs of an inverter bridge. Each winding of the first set of secondary windings is interconnected with a winding of the second set of secondary windings. Circuitry is provided for operating the inverter bridge such that a stepped phase output waveform is produced at each of a plurality of phase outputs.Type: GrantFiled: December 24, 1994Date of Patent: February 27, 1996Assignee: Sundstrand CorporationInventors: John Dhyanchand, Chai-Nam Ng, Vietson Nguyen, Richard Arbanella
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Patent number: 5355296Abstract: A switching converter includes first and second controllable switches, a power source coupled to the switches and a closed flux path. First and second primary windings are mutually inductively coupled through the closed flux path and are coupled to the first and second controllable switches, respectively. The first and second switches are operated together in synchronism and a secondary winding is inductively coupled with but electrically isolated from the first and second primary windings through the closed flux path. Each switch conducts only a portion of the power produced in the secondary winding and the problems of current sharing are avoided. Also, DC content that may be produced by the switches is blocked from the output.Type: GrantFiled: December 10, 1992Date of Patent: October 11, 1994Assignee: Sundstrand CorporationInventors: Ming Kuo, P. John Dhyanchand
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Patent number: 5317299Abstract: A summing transformer having a core structure, first primary and secondary windings wound on the core structure for establishing a rotating electromagnetic field when the first primary winding is energized, and second primary and secondary windings wound on the core structure for establishing a rotating electromagnetic field when the second primary winding is energized, and wherein the second first and second secondary windings are connected together so that voltages induced therein are added.Type: GrantFiled: July 3, 1991Date of Patent: May 31, 1994Assignee: Sundstrand CorporationInventors: P. John Dhyanchand, Jayant Vaidya, Rajhunath Mokadam, Richard Arbanella
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Patent number: 5301098Abstract: An inverter system for inverting variable input DC and providing therefrom controlled output AC including a feedforward sensor for sensing a variable parameter of the input DC, a feedback AC sensor for sensing the controlled output AC and an inverter controller responsive to the variable parameter of the input DC and to the controlled output AC for regulating the magnitude of the controlled output AC.Type: GrantFiled: July 9, 1992Date of Patent: April 5, 1994Assignee: Sundstrand CorporationInventors: P. John Dhyanchand, Vietson M. Nguyen, Sunil Patel, Chai-Nam Ng
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Patent number: 5281905Abstract: This invention relates to a hybrid AC/DC power source for aircraft power generation and aircraft engine starting. The power source employs an induction motor/generator and a converter for converting high frequency AC power into separate DC and low frequency AC power for use by aircraft electrical systems. The subject invention contemplates the provision of a driver for the motor/generator comprising a circuit for providing excitation to the motor/generator when it is operating as a generator, the circuit also converting AC power produced by the generator into the high frequency AC power for use by the converter. The converter comprises a first rectifier which produces the DC power and a second rectifier and an inverter which together produce the low frequency AC power. The generator produces uncontrolled frequency AC power. Bidirectional switches operate within the circuit to invert DC excitation power to produce power for the AC excitation and to rectify output of the generator into DC.Type: GrantFiled: December 14, 1989Date of Patent: January 25, 1994Assignee: Sundstrand CorporationInventors: P. John Dhyanchand, Vietson Nguyen
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Patent number: 5282125Abstract: Control pulses having a first frequency are supplied to the switches of an inverter by a controller. During initial operation of the inverter, however, a softstart circuit supplied pulses to the inverter switches of the inverter wherein the soft-start pulses have a second frequency. The second frequency is constant and higher than the first frequency.Type: GrantFiled: May 13, 1992Date of Patent: January 25, 1994Assignee: Sundstrand CorporationInventors: P. John Dhyanchand, Chai-Nam Ng, Sunil Patel, Vietson M. Nguyen
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Patent number: 5239454Abstract: An inverter for converting DC power into AC power includes first and second controllable switches which are alternately operated to produce first and second AC waveforms which are combined to form a composite AC waveform that assumes at least three different levels during a cycle of the AC power.Type: GrantFiled: November 27, 1991Date of Patent: August 24, 1993Assignee: Sundstrand CorporationInventor: P. John Dhyanchand
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Patent number: 5225973Abstract: A regulator circuit for an inverter having first and second inverter sections that develop first and second AC waveforms which are phase displaced by a variable angle .alpha. wherein the first and second AC waveforms are combined to produce AC output power includes a reference signal generator that develops a reference signal having a transition between two states at a first time, a memory storing a plurality of words each representing a value of .alpha. add a circuit for accessing the memory with a deviation signal such that the memory provides a word at an output thereof. A counter is provided and a timing circuit causes the counter to load the word at a time prior to the first time. At the first time a gating circuit provides a plurality of clock pulses to a clock input of the counter whereby the counter decrements the loaded word as the clock pulses are received by the counter.Type: GrantFiled: September 13, 1990Date of Patent: July 6, 1993Inventors: Sunil Patel, Chai-Nam Ng, Vietson Nguyen, P. John Dhyanchand
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Patent number: 5182535Abstract: A summing transformer for a star-delta inverter having a separate secondary winding for each primary winding for use in inverting variable frequency AC power into constant frequency AC power, the transformer comprising a plurality of core sections having principal legs on which primary windings are wound and secondary legs extending between adjacent said principal legs establishing shared flux paths.Type: GrantFiled: December 19, 1989Date of Patent: January 26, 1993Inventor: P. John Dhyanchand
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Patent number: 5177460Abstract: A summing transformer for a star-delta inverter having a single secondary winding for each group of primary windings for use in inverting variable frequency AC power into constant frequency AC power, the transformer comprising a plurality of core elements having principal legs on which primary windings are wound and secondary legs extending from said principal legs establishing flux paths, the legs of each core element defining apertures through which a single winding is magnetically linked to a group of primary windings.Type: GrantFiled: January 4, 1990Date of Patent: January 5, 1993Inventors: P. John Dhyanchand, Richard A. Arbanella, Raghunath G. Mokadam
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Patent number: 5097241Abstract: A cooling apparatus for windings provides the ability to cool transformer windings having many turns during high frequency use with most any coolant. The cooling apparatus comprises a thermally conductive, coolant-isolating conduit having a channel therethrough for the passage of coolant disposed between the turns of the winding in heat transfer relationship therewith.Type: GrantFiled: December 29, 1989Date of Patent: March 17, 1992Assignee: Sundstrand CorporationInventors: Edward Smith, P. John Dhyanchand
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Patent number: 5057808Abstract: A summing transformer includes first and second sets of primary windings, first and second sets of secondary windings inductively linked with the first and second sets of primary windings and a set of tertiary windings inductively linked with one of the first and second sets of secondary windings wherein the tertiary windigs are connected together and permit zero sequence currents to flow during a period of unbalanced load currents in the sets of secondary windings whereby the output voltages produced thereby are maintained in a substantially balanced condition during such period.Type: GrantFiled: December 27, 1989Date of Patent: October 15, 1991Assignee: Sundstrand CorporationInventor: P. John Dhyanchand
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Patent number: 5055700Abstract: A brushless generator which is operable in a generating mode to convert motive power into electrical power, and in a starting mode to convert electrical power into motive power includes a set of electrically conductive bars disposed on a rotor of the generator and which are interconnected to form a squirrel cage winding whereby AC power may be provided to a main generator portion armature winding which induces currents in the bars and causes the generator to operate as an induction motor. Circuitry is provided for periodically shorting a main field winding of the generator during operation of the generator in the starting mode to prevent damage thereto.Type: GrantFiled: October 16, 1989Date of Patent: October 8, 1991Inventor: P. John Dhyanchand
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Patent number: 5045991Abstract: A control for an AC/DC power converter having first and second switches and which converts an AC voltage supplied by an AC source into a DC voltage on a DC output conductor includes circuitry for developing an error signal representing the deviation of the DC voltage from a desired level and a multiplier coupled to the developing circuitry and responsive to the AC voltage for deriving a reference signal representing a desired current magnitude from the AC source. A current sensor develops a current magnitude signal representing the magnitude of the current from the AC source and a circuitry having a hysteresis characteristic compares the current magnitude signal with the reference signal to obtain a comparison signal.Type: GrantFiled: December 28, 1989Date of Patent: September 3, 1991Assignee: Sundstrand CorporationInventors: P. John Dhyanchand, Vietson Nbuyen