MPC based supervisory control design for a Free Electron Laser

This paper develops a Model Predictive Control based approach for controlling multiple Radio Frequency (RF) stations in a Free Electron Laser (FEL). Each RF station includes a klystron which delivers high RF power, of the order of 50 megawatts, to feed the cavities in which the electron beam is accelerated. A local PID controller at each RF station controls the RF voltage measured at the local cavities. The proposed MPC scheme acts as a supervisory control to keep the beam energy constant by adjusting the set points of the local PID loops. The concept has been successfully tested at the SwissFEL injector test facility with three full-scale RF stations.