1
Kenneth R Carr, Gregory I Rozman, Albert L Markunas, Michael J Hanson, Leland E Weber, James A Shippling, Malcolm J McArthur, Vijay K Maddali, Paul E Nuechterlein, Alexander Cook, Vietson Nguyen, Mario R Rinaldi: Engine starting system utilizing multiple controlled acceleration rates. Sundstrand Corporation, Jeffery J Makeever, July 4, 1995: US05430362 (77 worldwide citation)

A control for operating an electromagnetic machine in a starting mode of operation wherein the main armature winding of the machine receives electrical power from a controllable power source during the starting mode of operation, comprises a circuit for detecting a magnitude of a parameter of power ...


2
Gregory I Rozman, Vijay K Maddali, Albert L Markunas: Rotor position detector with back EMF voltage estimation. Sundstrand Corporation, Marshall O Toole Gerstein Murray & Borun, January 24, 1995: US05384527 (77 worldwide citation)

A detector for detecting rotor position of a brushless generator having a motive power shaft and a main generator portion having a set of armature phase windings capable of receiving AC power and developing a back EMF voltage during operation in a starting mode, includes a circuit coupled to the set ...


3
Vijay K Maddali, Albert L Markunas: Harmonic feedback control for an inverter. Sundstrand Corporation, Marshall O Toole Gerstein Murray & Borun, July 5, 1994: US05327335 (25 worldwide citation)

Harmonics in the AC output power of an inverter are sensed and are compared to corresponding references to produce a plurality of errors. These errors are used to produce a harmonic waveform which is in turn used in a triangular waveform PWM pulse generator to generate PWM pulses. The PWM pulses con ...


4
Gregory I Rozman, Vijay K Maddali: VSCF start system motor current estimator. Sundstrand Corporation, Wood Phillips Mason Recktenwald & VanSanten, September 10, 1991: US05047699 (20 worldwide citation)

The problem of excess size and weight resulting from the use of current sensors in a VSCF start system (10) is solved by a motor control (22) which utilizes a current estimator (68) to develop a current feedback value. The current estimator (68) is coupled to a rotor position detector (72) and an in ...


5
Gregory I Rozman, Vijay K Maddali: VSCF system with DC link harmonics control. Sundstrand Corporation, Wood Phillips Mason Recktenwald & Vansanten, May 14, 1991: US05016157 (19 worldwide citation)

The problem of reducing harmonic content of AC bus voltage in a power system (10) is minimized using a controller (30) for a PWM inverter (38). The controller (30) develops a duty cycle command on a line (40) for controlling operation of the PWM inverter (38). The controller (30) develops the duty c ...


6
Albert L Markunas, Vijay K Maddali, William J Peterson, Charles Romenesko: Carrier injection sensorless control of aircraft variable frequency wound field synchronous starter/generators. Hamilton Sundstrand Corporation, Stephen G Mican, April 25, 2006: US07034497 (17 worldwide citation)

A carrier injection sensorless (CIS) starting control system that is capable of determining the angular position and velocity of a rotor for a wound field synchronous machine at or near rest and comprises north-south pole determination and a variable or dual frequency carrier signal for improved per ...


7
Bryan W Dishner, Vijay K Maddali, P John Dhyanchand: Speed-limited electrically compensated constant speed drive. Sundstrand Corporation, Wood Dalton Phillips Mason & Rowe, June 20, 1989: US04841202 (16 worldwide citation)

An electrically compensated constant speed drive which is speed limited so that power flow through the speed compensation link is unidirectional includes a permanent magnet generator which is interconnected with a permanent magnet motor by a power converter. The permanent magnet generator and the pe ...


8
Gregory I Rozman, Vijay K Maddali, Kevin Dooley: Generating system with a regulated permanent magnet machine and an active rectifier. Hamilton Sundstrand Corporation, Stephen G Mican, July 15, 2008: US07400117 (11 worldwide citation)

An electromechanical power transfer system that transfers power between a prime mover and a direct current (DC) electrical system, comprises: a permanent magnet machine (PMM) that has a permanent magnet (PM) rotor coupled to the prime mover, a stator with a multiphase alternating current (AC) windin ...


9
Albert L Markunas, Vijay K Maddali: Active damping for synchronous generator torsional oscillations. Hamilton Sundstrand Corporation, Kinney & Lange P A, October 5, 2010: US07808215 (9 worldwide citation)

A generator control unit (GCU) provides active damping of a synchronous generator by monitoring the speed of the synchronous generator and detecting oscillations in the monitored speed. The oscillations are indicative of torsional oscillations within the mechanical drivetrain including the synchrono ...


10
Christopher E Hopkins, Albert L Markunas, Vijay K Maddali, Richard A Arbanella: Harmonic control for an inverter by use of an objective function. Sundstrand Corporation, Jeffery J Makeever, January 17, 1995: US05383107 (9 worldwide citation)

A control unit for an inverter determines an objective function based upon harmonic content in a minimum number of the phase-to-phase AC voltages produced by the inverter and controls the switches of the inverter so as to minimize the objective function to thus control the harmonic content in the in ...