Abstracts Brochure - CERN

WEPLS134
WEPLS135
WEPLS136
28-Jun-06 16:00 - 18:00 WEPLS — Poster Session
sequence have to be properly managed, otherwise, small current disturbance can occurs, which may disgrade the
stability of the performance of Superconducting Magnet.
Design and Modeling of the Step Down Piezo Transformer
The energy conversion and the step down
C.-Y. Liu, Y.-C. Chien, K.-B. Liu (NSRRC)
voltage waveform of the piezo transformer
are required to achieve optimal working condition
of the resonate frequency. To meet this requirement, a reliable and precise instrument is needed to scan the
resonated point of the piezo transformer such that the piezo transformer’s output performance can meet required
specification. In this paper, design and modeling of a new step down piezo transformer deployed in NSRRC is
described. This step down piezo transformer is capable of delivering energy conversion with high efficiency performance,
which is better than traditional transformer, and the voltage transfer ratio is correct. The simulation circuit
model used to develop driver circuit of the piezo transformer is also included in the design of this new step down
transformer. It has been tested and proven to be working well in power conversion with excellent efficiency and
reliability.
Piezoelectric Transformer Based Continuous-conduction-mode Voltage Source Chargepump
Power Factor Correction Electronic Ballast
This paper presents the piezoelectric trans-
R.L. Lin, H.-M. Shih (NCKU) C.-Y. Liu, K.-B. Liu (NSRRC)
former (PT) based continuous-conductionmode
(CCM) voltage source (VS) chargepump
(CP) power factor correction (PFC) electronic ballast. By replacing L-C resonant tank and transformer in
the conventional CCM VS CP PFC electronic ballast with PT, the cost and volume can be reduced. The main drawback
of conventional electronic ballast is that the input current has a narrow conduction angle, which causes rich harmonic
that pollute the power system. However, the conventional CCM VS CP PFC electronic ballast is able to solve this
problem but still require larger volume. Since the equivalent circuit of PT is identical to the conventional L-C resonant
tank used in CCM VS CP PFC electronic ballast, the L-C resonant tank can be replaced by the PT to reduce the cost
and volume. In addition, the inherent input capacitance of the PT works as a turn-off snubber for the power switches
to decrease the turn-off voltage spikes and thus reduces the turn-off losses of the switches. The results show that the
electronic ballast using PT achieved high power factor and the switches can be operated under ZVS condition.
Pulsed Magnet Power Supplies for Improved Beam Trajectory Stability at the APS
New power circuit and control electronics
B. Deriy, L. Emery, A.L. Hillman, G.S. Sprau, J. Wang (ANL) have been implemented in the septum power
supplies at the Advanced Photon Source
(APS). The goal was to meet a low pulse-to-pulse relative amplitude jitter of about ± 5·10 -4 for trajectory stability
in the booster-to-storage ring transport line. The original power supply design produced a jitter of ± 15e-4, which
made injection tuning difficult. The jitter for the two new booster pulsed magnet supplies is now 1.1e-4, as inferred
by a beam-based statistical analysis. A common design was made for all of the septum magnet power supplies at
the APS. The system, regulation algorithms, the results achieved, and the current regulation stability issues will be
discussed.
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