Supercapacitors Based Power Supply Design for Toroidal Field Coil of Upgrade Damavand Tokamak

In this study, the current discharge and the power supply system of toroidal field (TF) coils of Damavand tokamak have been designed and simulated to increase the magnetic field time and consequently the plasma duration. Currently, the TF coil current used to form and confine plasma has a sinusoidal half-cycle waveform with a duration of 100ms and a current peak of 12kA which produces a 1.1T magnetic field at the center of the chamber and its flat-top area is about 20ms. With the aim of upgrading Damavand tokamak, in order to increase the plasma duration to 200ms, it is necessary to upgrade the energy supply system and control system of toroidal and poloidal field coil currents. For this purpose, in this paper, the main power supply system has been designed based on super-capacitors with a capacitance of 21F, voltage of 900V, and topology of series-parallel (7*8). Also, to supply and stabilization of TF current, the chopper converter with seven parallel modules with the closed-loop control system with hysteresis controller has been designed and simulated. The general system is capable of supplying and stabilizing the magnetic field from the range of 0.7 to 1.2 Tesla with a ripple of less than 0.2% and a duration of 200ms for the flat area. Also, the charging system of super-capacitors has been designed and simulated using the 12-pulse rectifier converter and the buck converter with the constant current method, which has achieved desirable results.