Current ripple in the coils of the TJ-II Spanish stellarator

High precision coil current control, stability and ripple content are very important aspects for a stellarator design. The TJ-II coils will be supplied by network commutated current convertors and therefore the coil currents will contain harmonics which have to kept to a very low level. An analytical investigation as well as numerous simulations with EMTP, SABER(R) and other softwares, have been done in order to predict the harmonic currents and to verify the completion with the specified maximum levels. The calculations and the results are presented.