A novel control architecture for an active clamp flyback converter with a -5 kV output, to be used to power the cathode of a travelling wave tube within a microwave amplifier, has been developed and prototyped. The cathode presents a resistive load to the converter, which is pulsed across a wide range of frequencies and duty cycles. The converter must be operated in closed loop to minimize output voltage deviation (ideally within ±10 V). The controller is a standard PI, augmented with a non-standard feed-forward component: this architecture allows for a drastic reduction in the voltage deviation as the load is pulsed. In particular, simulation results indicate an order of magnitude reduction in voltage deviation when utilizing this controller instead of a standard PI. This performance improvement has been confirmed on the experimental prototype.
