Announcement of Approved Transactions Papers
Transactions Abstracts This section of IEEE Power Engineering Review serves to announce the approval of technical papers for publication in future issues of one of the three PES Transactions. The abstracts afford access to the essence and main contributions of each published paper. The abstracts are listed by Technical Committees, which appear in alphabetic order. To Order Technical Paper Preprints, Contact IEEE Customer Service, +1 800 678 4333 or +1 732 981 0060, fax +1 732 981 9667, e-mail
[email protected]. The IEEE member price for each paper Preprint is $3.50 plus delivery charges (nonmember price is $6.50 plus delivery charges). When you contact IEEE Customer Service, make sure that you identify the item you are ordering as a Preprint (not as a paper, reprint, article, etc.), and be sure to provide the Preprint order number. Discussion Deadlines for the papers are included with each technical paper abstract.
Approved Transactions Papers Call for Discussions Deadline: 31 October 2002 The IEEE Power Engineering Society publishes discussions and closures and makes them available for all accepted papers. Discussions form a most valuable adjunct to a technical paper and are strongly encouraged. Discussions must provide contributions through questions and/or additional information on the subject of the papers. Congratulatory discussions are discouraged and are subject to elimination. Combined discussions of two or more papers are not acceptable unless they refer to companion papers. Discussions are limited to 1,500 words (or an equivalent length if illustrations are used). Discussions are considered as final drafts that, upon acceptance by the Technical Committee, are ready to be printed without further changes. Referto the PES Publication Guide for submission specifications. The guide is available on the Web, http://www.ieee.org/power/authkit.htm, or through the PES Executive Office, fax +1 732 562 3881, e-mail
[email protected]. Submit discussions to the PES Executive Office no later than 31 October 2002 for papers abstracted in the August 2002 issue of IEEEPowerEngineering Review. Discussions received after that date will be returned to the discusser and will not be processed.
IF'LE
Power Lngineering Review,
Auigutst 200261
Electric Machinery
Measured Efficiency Improvements of Induction Motors with Thyristor/Triac Controllers Fuchs, E.F.; Hanna, W.J. Author Affiliation: University of Colorado. Abstract: The deployment of inexpensive thyristor/triac controllers improve the efficiency and do not increase the power factor of induction motors (as measured at the input of pole transformer) operating under variable torque and constant speed constraints. Computer-aided testing yields detailed input/output powers for the drive. The improvement of the power factor does not increase the real-power capability (RPC) of a transformer supplying power to such drives due to current harmonics. Although the total harmonic current distortion (THDi ) may exceed IEEE 519 and IEC 555 recommendations, recent publications show that the impact on the apparent power derating of a 25 kVA pole transformer is small if the THDi is less than 50%. Keywords: Thyristor/triac controller, energy savings, efficiency improvement, total harmonic distortion, apparent power derating and real-power capability of transformer. Preprint Order Number: PE-608EC (05-2002) Discussion Deadline: October 2002
Sensorless Scalar Controlled Induction
Motor Drives with Modified Flux Observer Wang, C.C.; Fang, C.H. Author Affiliation: Ching Yung Institute of Technology; National Chiao Tung University. Abstract: This paper presents a simple sensorless scalar control algorithm to control the speed of an induction motor. First, a modified flux observer was employed to estimate the stator flux with the voltage command and the feedback current. Then, based on the mathematical model of the induction motor, the slip-frequency was calculated and the frequency of the voltage command was compensated. An auto-boost controller was designed to overcome the decrease in voltages of the stator resistance and to maintain constant stator flux amplitude. To improve the pure integration problem, a high-pass filter was installed in the stator flux observer. In this filter, the cut-off frequency is proportional to the voltage frequency; therefore, the phase shift and amplitude degradation of the estimated flux can be corrected easily. Finally, to demonstrate the proposed control algorithm, a PC-based experimental system was constructed in a 1 hp induction motor. Experimental results are presented to validate the effectiveness of our design. Keywords: Induction motor, sensorless control, scalar control, flux observer, slip estimator. Preprint Order Number: PE-742EC (05-2002) Discussion Deadline: October 2002 61
