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Ha, K.M.

Paper Title Page
MPPP003 FALSE BPM READINGS AFFECTING ORBIT FEEDBACK 847
 
  • H.-S. Kang, J. Choi, M.-H. Chun, K.M. Ha, J.Y. Huang, Y.-C. Kim, E.-H. Lee, T.-Y. Lee, W.W. Lee, J.-H. Suh
    PAL, Pohang, Kyungbuk
 
  Funding: Ministry of Science and Technology, Korea.

A slow global orbit feedback (SOFB) is routinely operating in the usual user service operation at PLS. The orbit feedback uses 22 correctors in each plane which have 20-bit capability for the vertical plane and 16-bit capability for the horizontal plane, and the feedback speed is 4 seconds. The orbit stability in RMS was maintained below 1 mm in both planes for one hour and 3 mm for a 12-hour operation. The BPM chamber movement due to the change of synchrotron radiation heat load mainly limits the SOFB performance. The intensity dependence of BPM electronics is well compensated by a look-up table of BPM.

 
WPAE061 LC Filter for High Accuracy and Stability Digital MPS at PLS 3550
 
  • S.-C. Kim, J. Choi, K.M. Ha, J.Y. Huang
    PAL, Pohang, Kyungbuk
 
  Funding: Work supported by the Ministry of Science and Technology, Korea.

High accuracy and stability digital power supply for magnet is developed at PLS. This power supply has three sections. The first section is digital controller including DSP&FPGA and precision ADC, the second consists of IGBT driver and four quad IGBT switch, and the third is LC output section. AC input voltage of power supply is 3-phase 21V, output current is 0 ~ 150 A dc. Switching frequency of IGBT is 25 kHz. The output current of power supply has very high accuracy of 100 mA step resolution at full range and the stability of ± 1.5 ppm for short term and ± 5 ppm for long term. This paper describes characteristics of filter and output current performance improvement after LC output filter at four quad digital power supplies.