Fast Transient Recovery of Common DC Bus Architecture with Large Signal Based Tuning Approach

The generic architecture of a common DC bus configuration is designed using multiple interconnected power converters connected in cascaded/parallel fashion. A rigidly controlled power consuming converter (PCC) behaves as constant power type load (CPL) across common bus. Moreover, a load transient across PCC results as power transient for power delivering converters (PDCs). Due to interconnected system configuration, coupling effect emerges during small signal based (SSB) controller tuning process. In order to fulfill margin requirements, the controller may need to be tuned repeatedly. Moreover, tuned parameters may not result in fast transient performance considering wider operating range. To achieve faster transient recovery, the large signal based (LSB) tuning approach with peak current mode control followed by output current feed-forward logic is adopted in this work for the droop controlled PDCs. The effect of droop term is considered during the derivation of proportional gain magnitude for load step up transients in PCCs. Implementation procedure along with simulation case studies is presented considering different load step up transient cases for the overall interconnected convert system. This control approach helps to acquire fast transient response without disturbing operation of other PCC in the system.