Design of standalone closed-loop piezoelectric valve control system using microcontroller for gas-feed system in Aditya-upgrade Tokamak

Gas fueling in Tokamaks is a critical parameter, for maintaining and controlling the plasma density. Normally in ADITYA Upgrade Tokamak, plasma discharges are initiated with prefill gas pressure and later additional gas is introduce into the vessel through multiple gas puff pulses. The pre-fill gas feed is applied about 150 ms prior to the application of loop voltage. A programmable pulse generator is used for multiple gas puffs to control the fuel gas. In the absence of real time density feedback at present, these gas-feed pulses are prefixed prior to the initiation of the discharge. This paper describes the salient features of the design in detail