Power converters for the magnets of the Linac Warm Units of ESS

ESS, the European Spallation Source, will be a major user facility at which researchers from academia and industry will investigate scientific questions using neutron beams. ESS will deliver its protons to a solid, rotating tungsten target, which will in turn generate neutrons. A linear accelerator (Linac) creates protons at the ion source, accelerates them to an appropriate energy and steers them onto the target to create neutrons via the spallation process. Among the cryogenic accelerating sections, there are “warm” magnets for correcting the proton beam “optics”. This paper reports the chosen strategies for the power converters in these LWUs (Linac Warm Units). Amongst the power converters, we will highlight the 4-quadrant corrector magnets ones, based on a high precision and high bandwidth MOSFET H-bridge chopper, and a proposed novel topology for pulsed quadrupole magnets, instead of traditional DC ones. We will also demonstrate the interest of using pulsed magnets in place of DC ones in low duty-cycle Linacs, reducing the magnet losses and therefore the power consumption up-to 90%.