Development of a large-current high-precision pulse power supply

JAEA and KEK are jointly constructing a high‐intensity proton accelerator project J‐PARC. Its main accelerator is a 3‐GeV synchrotron. Its injection bump magnets, especially horizontal paint bump magnets, are excited by large pulse currents. Their rated currents are over 10 kA and pulse widths are about 1 ms. Tracking errors are required to be less than 1%. Multiple connected two‐quadrant IGBT choppers are adopted for their power supplies. Their output currents are controlled by feedback control with minor loop voltage control (m‐AVR). When output current of a chopper intermits at small current, its output voltage rises and current control becomes difficult. In this paper, response of m‐AVR and output voltage characteristics at current intermittent region are studied and an improved control scheme is proposed. The performance is confirmed by a test. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(3): 62– 72, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20783