Browsing by Author "Yeh, ST"

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DSP-based rotor time constant identification and slip gain auto-tuning for indirect vector-controlled induction drives
(1996)
Tzou, YY
;
Yeh, ST
;
Wu, H
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交大名義發表
;
電控工程研究所
This paper proposes a systematic rotor time constant identification and auto-tuning scheme for vector-controlled induction drives with unknown rotor time constant. The theoretical aspects and practical implementation issues of the proposed scheme have been described. The proposed scheme has been realized using dual-DSP based software control techniques. Experimental studies have been carried out to illustrate the decoupling control effect of the proposed rotor time constant auto-tuning scheme.
Highly automatic measurement system for three orthogonal magnetic moments of a permanent magnet block
(1996-05-01)
Hwang, CS
;
Yeh, ST
;
Teng, PK
;
Uen, TM
;
電子物理學系
A highly automatic system with a three-angle rotation mechanism has been designed and constructed to measure several thousand permanent magnet blocks. The system's main features include its high speed, highly automatic measurement, and the ease with which the different size magnet blocks can be installed and removed. This system provides precise and accurate measurements of the three orthogonal magnetic moment components to accurately characterize each block, as deemed necessary to assess the field quality of undulators and wigglers. A three-angle in rotation mechanism, together with a simple mathematical algorithm is used to measure and analyze the magnetic moments of the magnet block. The system includes the Helmholtz coil pair, block holder, the three-degree rotation mechanism, and the control and data acquisition system. A power train system consists of one motor coupled with a nonmagnetic stainless steel for 360 degrees rotation and two motors individually coupled with two groups of nonmagnetic time belts for rotation angles of 0 degrees, 180 degrees, 0 degrees, and 90 degrees. The control system uses a microcomputer together with a stepping motor control card and a digital fluxmeter connected by the general purpose interface bus. The measurement speed of this system is 40 blocks per h. One reference magnet was measured, with those results verifying the long term precision of the order of 0.04% for the easy component and 0.02 degrees for two minor components. The coil-pair geometry factor is calibrated via the voltage-field reciprocity principle, indicating that the system absolute accuracy is around 0.43%. (C) 1996 American Institute of Physics.
Performances and characteristics of a prototype symmetric hybrid adjustable phase undulator
(1997-11-11)
Hwang, CS
;
Chang, CH
;
Fan, TC
;
Lin, FY
;
Wang, C
In this work, we construct and measure a prototype symmetric Hybrid Adjustable Phase Undulator (HAPU) with nine poles to compare phase change and gap change in terms of their features and performances. HAPU can also provide the different characteristics between the pure and hybrid adjustable phase undulator. The HAPU has been installed in the Synchrotron Radiation Research Center (SRRC) storage ring to test the performance of the beam dynamics and photon flux behavior. A three-orthogonal Hall probe and a long-loop-coil measurement system are also implemented to take the field measurements. The multipole field and electron trajectory correction are made by shimming, the magic finger, and the active end pole coil corrector. After the field measurements, the vertical integral strength of HAPU is markedly smaller than that of the Hybrid Adjustable Gap Undulator (HAGU) and confirm that no obvious distinction arises between HAPU and HAGU in terms of the spectrum flux. The electron beam dynamic performance in the storage ring indicates that the vertical tune shift of HAPU is three times smaller than that of HAGU. Meanwhile, the energy dynamic tuning with the digital global feedback turned on, the photon position and flux in the bending chamber beam line is invariant. In addition, the injection efficiency remains unaffected at any phase position and the electron beam lifetime does not change when HAPU is in the dynamic tuning.
Synthetic studies towards laurobtusol.
(1998-08-23)
Ho, TL
;
Yeh, ST
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應用化學系
;
Department of Applied Chemistry
The construction of a 9-pole prototype for SRRC U-10 undulator
(1996-07-01)
Chang, CH
;
Chang, LH
;
Chen, HH
;
Fan, TC
;
Hwang, CS
A 9-pole undulator prototype with a magnetic period length of 10 cm was designed and constructed to examine the mechanical and magnetic field performance. The hybrid permanent magnet structure was optimized by using 2D ''PANDIRA'' and 3D ''TOSCA'' magnetostatic codes. A half period magnet model was also fabricated to verify the magnetic Period length field strength on-axis and the transverse field roll-off within 0.1 % in the good field region of +/- 10 mm at a minimum gap of 22 mm. The end pole configurations, as equipped with either two tunable permanent magnetic rotators or steering coil correctors were designed for minimizing the deviation of the magnetic field strength integrals. The magnet structures were mounted bn a 2 meter long C-frame support structure in which the gap could be moved in parallel and phase motion. The field characteristics, and measurement results between the adjustable gap undulator (AGO) and the hybrid adjustable phase undulator (APU) were also presented.