Integration studies of RF solid-state generators in the electrical system of NBTF experiments and ITER HNB

SPIDER operation, started in 2018, pointed out performance-limiting issues caused by the technology employed RF generators, based on tetrode free-running oscillators. One of these limits, namely onset frequency instabilities, prevented operation at full rated power 200 kW. In addition, tetrodes require high voltage to operate, which translates risk flashovers and necessity perform conditioning procedures, limiting overall reliability. These disadvantages, combined with positive experience gained meanwhile smaller facilities solid state amplifiers, led proposal a complete re-design radiofrequency supplies. This paper describes modelling activities used define specifications design criteria solid-state amplifiers for MITICA, can be directly transposed ITER HNB units when their functionality is proven. We detail topology consisting class D amplifier modules achieve required kW, mainly driven deliver nominal ion source, mitigate obsolescence, improve reliability through modularity. Due non-standard application, we gave particular focus integration generators systems MITICA. Numerical analyses were performed verify impact harmonic distortion transmission line load components, address effect mutual coupling between circuits generator output modulation, assess magnitude common mode currents electric system. studies, as well from helped dedicated circuit provisions control strategies, are currently being implemented detailed construction phase new amplifiers.