Online feedforward calculation for plasma shape control in tokamaks with superconducting coils

In this work, we describe a method for online calculation of the feedforward component of a combined feedforward/feedback simultaneous control of plasma current and boundary shape in tokamaks with superconducting control coils. Use of this online feedforward calculation method is intended to significantly reduce the feedback gains required for plasma shape and current control. It also supports graceful degradation of shape and plasma current control when one or more control coil currents or voltages approaches a limit. This method was implemented and experimentally tested on the KSTAR tokamak with initial results that included a near zeroing of previously required very high integral gains.