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osu1116338965.pdf (1.1 MB)
ETD Abstract Container
Abstract Header
Flux and speed estimation techniques for sensorless control of induction motors
Author Info
Comanescu, Mihai
Permalink:
http://rave.ohiolink.edu/etdc/view?acc_num=osu1116338965
Abstract Details
Year and Degree
2005, Doctor of Philosophy, Ohio State University, Electrical Engineering.
Abstract
The focus of this research is the development of novel techniques for estimation and control of sensorless induction motor drives. In a sensorless drive, the speed must be estimated from the system measurements. Depending on the objective of the control (speed or torque control), the speed estimate must be used in one or more areas of the control scheme. This idea and the main techniques for speed estimation are explored. The dissertation investigates the issues related to low-speed flux estimation when a Voltage Model observer is used. Pure integration cannot be implemented due to offsets in the measured signals and integrators must be replaced by low pass filters. At low speed, the flux estimates are incorrect in both magnitude and angle; consequently, the rotor position obtained by the DFO method is incorrect. An improved Voltage Model observer that corrects the errors is developed based on a Programmable Low Pass Filter and a vector rotator. The method requires estimation of the stator frequency and this is done by a Phase Locked Loop synchronized with the voltage vector. The traditional rotor flux MRAS method can be used for speed estimation, however, under non-ideal integration the dynamics of the speed estimate exhibits right-hand side plane zeros. Additionally, system tuning is difficult and may yield under damped responses. Two novel Sliding Mode MRAS observers are designed and implemented and their features are used for speed estimation. The d-q rotational frame currents of an induction machine are not decoupled. Decoupling can be achieved by canceling the cross-coupled terms in the equations of the synchronous frame currents. This approach is both inconvenient and inaccurate. A novel approach for decoupling is presented: an Integral Sliding Mode controller complements a traditional controller that acts on a simulated plant. The use of the Integral SM controller guarantees that the currents in the real plant will track those of the simulated model. The additional controller compensates for the cross-terms and for variations of the machine parameters. The method is also valuable for allowing fast and efficient tuning of the current controllers.
Committee
Longya Xu (Advisor)
Pages
124 p.
Keywords
induction motor
;
sensorless control
;
flux estimators
;
speed estimators
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Citations
Comanescu, M. (2005).
Flux and speed estimation techniques for sensorless control of induction motors
[Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1116338965
APA Style (7th edition)
Comanescu, Mihai.
Flux and speed estimation techniques for sensorless control of induction motors.
2005. Ohio State University, Doctoral dissertation.
OhioLINK Electronic Theses and Dissertations Center
, http://rave.ohiolink.edu/etdc/view?acc_num=osu1116338965.
MLA Style (8th edition)
Comanescu, Mihai. "Flux and speed estimation techniques for sensorless control of induction motors." Doctoral dissertation, Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1116338965
Chicago Manual of Style (17th edition)
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Document number:
osu1116338965
Download Count:
4,528
Copyright Info
© 2005, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.