Simultaneous feedback control of the toroidal field and plasma current on MST using advanced programmable power supplies*

Programmable control of the inductive electric field enables advanced operations of reversed field pinch (RFP) plasmas in the MST device. MST’s poloidal and toroidal magnetic fields (Bp and Bt) can be sourced by IGBT-based programmable power supplies (PPSs). In order to provide real-time simultaneous control of both Bp and Bt circuits, a time-dependent integrated model is developed. The actuators considered for the control are the Bp and Bt primary currents sourced by the PPSs. The control system goal will be tracking two particular demand quantities, in this case, the plasma current Ip, directly related to Bp, and the RFP reversal parameter F, closely related to both Bp and Bt. To understand the responses of Ip and F to the actuators and to enable systematic design of control algorithms, dedicated experiments are run in which the actuators are modulated, and a linearized dynamic data driven model is generated using the system identification method. We perform a series of real time experiments to test the designed controller and validate the derived model predictions.