A novel active bouncer system for klystron modulators with constant AC power consumption

A new linear accelerator under study at CERN (CLIC-Compact Linear Collider) [1] requires the design of a new klystron modulator capable of producing 150 KV and 160 A square shaped pulses with a repetition rate of 50 Hz and a flat-top length of 140 μs. The whole complex will include more than 1600 modulators of 24MW each, synchronously operated. With this operating mode, a total pulsed peak power of 37 GW must be produced, equivalent to 300 MW of average power consumption. The utility grid can tolerate a few percent of power fluctuation, and the klystron modulators system must be designed such that a constant power (300 MW) only is withdrawn from the AC network. This power fluctuation can be reduced either by passive or active solutions. Typical capacitor discharge based klystron modulators are already attenuating this effect by a considerable amount (typically ~90% of power fluctuation attenuation). However, because of design constraints, the capacitor bank cannot ensure a perfect attenuation of the power consumption fluctuation from the AC network. Therefore, additional active or passive solutions must be foreseen in order to resolve the power fluctuation issue.