Design and test of a mitigation system against voltage ringing in MITICA Acceleration Grid Power Supply

Abstract The Acceleration Grid Power Supply of MITICA is a high power, high voltage power supply devoted to feed the acceleration grids of the full scale prototype of the ITER NBI injector. It is divided in two subsystems: the AGPS – Conversion System (CS) and the AGPS – DC Generator (DCG), procured by different domestic agencies. Numerical simulations have pointed out a voltage ringing at the interface of the two systems, which would generate repeated high overvoltage at the input of the AGPS-DCG, not in compliance with the interface requirements. The phenomenon has been investigated and a solution for the mitigation has been identified based on a suitable low pass RC filter, as a trade-off between simplicity and effectiveness. The filters have been successfully tested directly with the AGPS-CS to demonstrate the reduction of the voltage peaks in the operation condition foreseen for the AGPS.