Minimization of torque ripples in direct torque control of induction motor at low speeds

Direct Torque Control (DTC) of induction motor has attracted a considerable attention in the motor drives industry. The key merits of DTC include fast torque dynamic response, simple structure, insensitivity to motor’s parameters. Nevertheless, DTC inherently suffers from two major downsides namely:...

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Main Author:	Abdullah Ajlan, Abdullah Ali
Format:	Thesis
Language:	English
Published:	2016
Subjects:	TK Electrical engineering Electronics Nuclear engineering
Online Access:	http://eprints.utm.my/id/eprint/80842/1/AbdullahAliAbdullahMFKE2016.pdf
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id	my-utm-ep.80842
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spelling	my-utm-ep.808422019-07-24T00:07:53Z Minimization of torque ripples in direct torque control of induction motor at low speeds 2016-06 Abdullah Ajlan, Abdullah Ali TK Electrical engineering. Electronics Nuclear engineering Direct Torque Control (DTC) of induction motor has attracted a considerable attention in the motor drives industry. The key merits of DTC include fast torque dynamic response, simple structure, insensitivity to motor’s parameters. Nevertheless, DTC inherently suffers from two major downsides namely: high torque ripples and variable switching frequency. This thesis presents a new technique to minimize the torque ripples inherited in the digital-based DTC of induction motor. The typical discrete-based DTC imposes a delay time which frequently allows the torque to overshoot beyond hysteresis bands. This triggers the selection of reverse voltage vectors which, in turn, cause large torque decrements. The torque ripples become of great significance at low speeds where torque overshoot is most likely to occur due to steep positive torque slope. A multi-level DC link voltage is proposed to vary the DC voltage of Voltage Source Inverter (VSI) according to motor’s speed. By varying the DC link voltage, the torque slopes can be controlled and, hence, the torque overshoots are mostly avoided. Therefore, the torque ripples are significantly minimized. The viability of proposed technique has been validated using MATLAB/Simulink software. Results show the proposed technique may yield over 50% reduction in the RMS torque ripples while maintaining a low switching frequency. Also, the torque dynamic response is maintained as good as in the conventional DTC scheme 2016-06 Thesis http://eprints.utm.my/id/eprint/80842/ http://eprints.utm.my/id/eprint/80842/1/AbdullahAliAbdullahMFKE2016.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:120530 masters Universiti Teknologi Malaysia, Faculty of Electrical Engineering Faculty of Electrical Engineering
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	TK Electrical engineering Electronics Nuclear engineering
spellingShingle	TK Electrical engineering Electronics Nuclear engineering Abdullah Ajlan, Abdullah Ali Minimization of torque ripples in direct torque control of induction motor at low speeds
description	Direct Torque Control (DTC) of induction motor has attracted a considerable attention in the motor drives industry. The key merits of DTC include fast torque dynamic response, simple structure, insensitivity to motor’s parameters. Nevertheless, DTC inherently suffers from two major downsides namely: high torque ripples and variable switching frequency. This thesis presents a new technique to minimize the torque ripples inherited in the digital-based DTC of induction motor. The typical discrete-based DTC imposes a delay time which frequently allows the torque to overshoot beyond hysteresis bands. This triggers the selection of reverse voltage vectors which, in turn, cause large torque decrements. The torque ripples become of great significance at low speeds where torque overshoot is most likely to occur due to steep positive torque slope. A multi-level DC link voltage is proposed to vary the DC voltage of Voltage Source Inverter (VSI) according to motor’s speed. By varying the DC link voltage, the torque slopes can be controlled and, hence, the torque overshoots are mostly avoided. Therefore, the torque ripples are significantly minimized. The viability of proposed technique has been validated using MATLAB/Simulink software. Results show the proposed technique may yield over 50% reduction in the RMS torque ripples while maintaining a low switching frequency. Also, the torque dynamic response is maintained as good as in the conventional DTC scheme
format	Thesis
qualification_level	Master's degree
author	Abdullah Ajlan, Abdullah Ali
author_facet	Abdullah Ajlan, Abdullah Ali
author_sort	Abdullah Ajlan, Abdullah Ali
title	Minimization of torque ripples in direct torque control of induction motor at low speeds
title_short	Minimization of torque ripples in direct torque control of induction motor at low speeds
title_full	Minimization of torque ripples in direct torque control of induction motor at low speeds
title_fullStr	Minimization of torque ripples in direct torque control of induction motor at low speeds
title_full_unstemmed	Minimization of torque ripples in direct torque control of induction motor at low speeds
title_sort	minimization of torque ripples in direct torque control of induction motor at low speeds
granting_institution	Universiti Teknologi Malaysia, Faculty of Electrical Engineering
granting_department	Faculty of Electrical Engineering
publishDate	2016
url	http://eprints.utm.my/id/eprint/80842/1/AbdullahAliAbdullahMFKE2016.pdf
_version_	1747818269960568832

Minimization of torque ripples in direct torque control of induction motor at low speeds

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