Performance of the pls high precision magnet power supplies

In the PLS (Pohang Light Source), more than 200 units of uni-polar and bi-polar high precision magnet power supplies (MPS’s) have been operated since 1994. The unipolar MPS’s are 12-step SCR rectifier type, and the bipolar MPS’s are H-bridge type choppers that adopt IGBT’s. Also, 144 units of transistor linear-type shunt controllers for the BBA (Beam-Based Alignment) application were added in 1997. The storage ring operation of the PLS starts with injection of 2-GeV beam from the PLS linac, and the beam energy is ramped to 2.5 GeV for normal operation by increasing operation currents of MPS and output powers of RF stations. In this paper, we discuss technical details and performance-test results of the PLS high precision MPS’s, and introduce our upgrade plan of the MPS’s Transistor-type linear shunt controllers are connected in parallel with quadrupole power supplies for the orbit correction of stored beam. Total 144 BBAPS (Beam Based Alignment Power Supply) are installed in 1997. BBAPS can control 10% of quadrupole magnet current. Fig. 3 and 4 show the wire connection of BBAPS and quadrupole MPS.