Active damping filter for high bandwidth - Low ripple pulsed converters

This paper presents a topological improvement for high performance pulsed converters, consisting of an IGBT or MOSFET based non-linear active damping of the output filter of a switch-mode power converter. The new generation of pulsed power converters needs to achieve higher levels of bandwidth, lower ripple and higher efficiency. Passive damping filters used to prevent the peak at the resonant frequency are common in power designs where the switching frequency and the bandwidth of the system are close. A dynamic control of the damping factor allows pushing further the bandwidth in presence of large transients and reducing it during steady state in order to minimize the influence of the switching frequency harmonics. Numerical simulation results, the adaptive control strategy to manage the non-linear filter behaviour, as well as an experimental validation consisting in the measurement of the proposed filter transfer function are presented. Results show that the proposed strategy easily allows an important ripple reduction combined with an increase in bandwidth of more than 50%.