Characterizing and developing circuit models for improved control of inductive helicity injectors on HIT-SIU

The new HIT-SIU experiment at the University of Washington continues the study of Steady Inductive Helicity Injection (SIHI) for the formation and sustainment of spheromaks. SIHI utilizes one or more injectors, which are each inductively driven by independent “voltage” and “flux” circuits. To better understand and control the behavior of these circuits on the HIT-SIU experiment, state estimation techniques were implemented so that the system may be observed in real time by the GPU controller [1]. In order to verify the accuracy of these methods, a full model of the circuits was first constructed and tested, with the goal of replicating the vacuum state of the circuits. Kalman filtering was used in a closed feedback control model of these circuits which yielded an effective algorithm for optimizing the circuit dynamics and behavior. Future plans on design and implementation of a fully predictive control model of the voltage and flux circuits will also be presented. Work supported by ARPA-E award DE-AR0001266 and CTFusion, Inc. under ARPA-E award DE-AR0001098.