University of Tennessee Research Foundation

Gm Global Technolgoy Operations, Inc.

The United States of America As Represented by the Administrator of the

Bimal K Bose

Kaushik Rajashekara

Jih-Sheng Lai

Nitinkumar R Patel

Ronald A Martin

Ronald J Spiegel

David Ross Crecelius

Marcelo Godoy Simoes

Malakondaiah Naidu

An induction motor drive uses direct vector control for zero speed start up. According to the invention, a speed sensorless induction motor is controlled at all speeds, including zero or substantially zero speed, using direct vector control. In order to utilize direct vector control at all speeds, it is necessary to derive accurate stator flux vectors at all speeds. This is accomplished in the present invention by calculating two sets of stator flux vectors in diverse manners. A first set of flux vectors is derived from measured stator terminal voltage quantities, and a second set of flux vectors is derived from measured stator current quantities. The first set of flux vectors is valid at non-zero speed and the second set of flux vectors is valid at substantially zero speed. The direct vector control utilizes one of the two sets of flux vectors in accordance with predetermined criteria indicative of zero and non-zero speed conditions.

Zero speed start-up for a speed sensorless induction motor drive

A speed sensorless hybrid vector control starts from zero speed by using indirect vector control with stator frequency equal to slip frequency. As soon as the rotor begins to rotate, the drive is converted to direct vector control for normal operation. The direct vector control uses several low pass filters. The first is a harmonic reducing filter for the sensed motor phase current and voltage signals. The others comprise integration apparatus used in the calculation of motor flux quantities from the motor phase current and voltage signals. One of these other filters has a phase lag which is variable in response to stator frequency to compensate for phase lag introduced by the harmonic reducing filter; and the apparatus is thus able to produce a phase compensated set of unit vectors for vector rotation of the commanded stator voltage components from the synchronous to the stationary reference frame as well as a set of non-phase compensated unit vectors for inverse vector rotation of the estimated stator current components from the stationary to the synchronous reference frame. This allows the motor to operate at any point in the torque speed range, down to zero speed if a braking load torque is applied against a smaller input commanded torque, with the resulting torque current flow allowing the drive to remain in direct vector control.

Speed sensorless hybrid vector controlled induction motor with zero

A control system utilizing fuzzy logic adaptive control to control the operation of a wind turbine driven electric power generator to control power generator speed and hence power frequency while maximizing the power output of the power generator. Wind turbulence effects are eliminated and airgap magnetic flux of the power generator is controlled.

Fuzzy logic integrated electrical control to improve variable speed wind

The invention comprises an apparatus and a method for controlling permanent magnet AC machines. Stator voltages and stator currents are sensed to produce signals which are utilized by a digital circuit to calculate control signals for the machine.

Rotor position estimation of a permanent magnet synchronous-machine for

A circuit for converting a DC voltage to a pulsating DC voltage useful as a power source for operating an AC machine. The circuit includes means for controlling the amplitude of the pulsating DC voltage as the load changes and means for controlling the duration of the pulses comprising the pulsating DC voltage.

High frequency quasi-resonant DC voltage notching scheme of a PWM

The invention comprises a DC link resonant converter for controlling the speed of AC machines. Switch and power supply means is provided to establish a bi-directional initial current in the resonant circuit. By selecting the plurality and magnitude of the initial current, the peak voltage of the resonant link is controlled, and reliable zero crossing of the resonant voltage is assured. Current technology permits resonant frequencies in the range of 50-100 kilohertz to be utilized.

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Knoxville, TN, United States of America

Bimal K Bose