Direct digital control of superconducting magnet

The SM (superconducting magnet) current feedback control of I-C unit (inductor-converter unit) has to be designed to maintain stability, considering that the time constant of transfer function from SM current to SM terminal voltage is very large. For accurate control, it is also very important to take into account the current and magnetic field distributions inside the SM, ac loss and stray capacitances between coils. In this paper, direct digital control systems such as PID system, first-order time lag system with dead time element, finite time setting control system (FTSC) and model reference adaptive control system (MRAS) are proposed. Control characteristics of these control systems are analyzed by experiment and simulation.