A multi-loop control system for series DC active filter in a medium-voltage DC amplifier

In order to cope with increasing power demand onboard future combatant ships, US navy has embarked on medium-voltage dc as the next generation integrated power system. A viable dc power supply system solution for such ships is based on the mature technology of multi-pulse thyristor bridge front-end rectifiers. Due to the intrinsic ripple characteristic associated with thyristor commutations in such front-ends, a high bandwidth series dc active filter can be used to smooth out the dc-bus. In this paper, we propose a new multi-loop feedback and feed-forward control system for the series dc active filter in order to meet the stringent dc-bus ripple attenuation and disturbance rejection requirements. Analysis and simulations results show promise of multi-loop control scheme. Experimental results of the 12kVA/400Vdc laboratory test-bed with feed-forward control are provided.