AC-DC converter power modules of a solid state modular high voltage DC power supply

A novel solid state modular -100 kV, 25 A DC power supply having pulse capability is employed to bias 1 MW, 352.2 MHz klystron amplifier in high power radio frequency (RF) test stand developed at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore. This power supply consists of 176 numbers of IGBT based switch power modules connected in series to provide -100 kV DC output voltage. All these power modules are operated at 1 kHz and suitably staggered to minimize output ripple as well as output stored energy. The designs of power module and output filter network are challenging tasks to meet the requirements of both continuous wave (CW) and pulse mode operations of this klystron bias power supply and their crucial aspects are presented in this paper. PSpice simulation of power module and output filter are carried out and also presented in this paper. The power supply was operated at typical operating points in both CW as well as pulse modes and experimental results are presented in this paper. Output peak to peak ripple less than 0.5 % and output stored energy less than 10 J are achieved in CW mode of operation. In pulse mode with 2 ms pulse length at 40 Hz repetition rate, typical rise time of 93 μs and fall time of 109 μs with droop of 0.1 % are achieved.