DC THYRISTOR SWITCHING ELEMENTS FOR FUSION EXPERIMENTS

General criteria for the analysis of thyristor valves used as switching elements in the energy transfer units of fusion experiments are examined in the paper. At first the parameters of the commutation network are singled out as a function of the current derivative at current extinction and of the counter polarization time of the thyristors. Afterwards the effect of the use of saturable reactors is analyzed, and an application to the RFX energy transfer units is drawn. Finally, considerations about the convenient junction working temperature of the thyristors from an economic point of view are given.