Switch Mode Power Converter Section (SMPCS)

High Stability (±10 ppm) Magnet Power Converter

Future accelerators such as Low Emittance Storage Ring (LESR) would demand power converter with output current stability of the order of ±10 ppm. While power converters with output current stability of ±50 ppm have been successfully developed and are being regularly used in Indus-2, the development of a magnet power converter with ±10 ppm stability needs special attention broadly in two areas - (1) power converter along with the control electronics and (2) precision sensing, and measurement of magnet current for performance qualification. The power part for 300 A, 90 V power converter has been designed, simulated at RRCAT and manufactured at ECIL, Hyderabad in close collaboration. Work on the control part was initiated on two fronts: refinement of existing analog controller and development of new digital controller. An improved version of analog control card, has been developed with refined circuit design, improved integrated circuits and better components. Further, an FPGA based digital control card has been developed, which retrofits the analog control card. This card is programmed with high resolution (21-bit) feedback control scheme with digital pulse-width-modulation. The power converter has been tested with both the cards to demonstrate the output current stability within +/- 10 ppm.

Photograph of high stability magnet power converter