Control of a Multi-Input Converter Using Dynamic Input Allocation

This paper deals with current sharing problem for interconnected power converters in DC microgrids. Specifically, it considers as a case study a multi-input converter (MIC), including two voltage sources connected to a common DC bus with a bulk capacitor through two parallel synchronous boost converters and an aggregated load modelled as an ideal current source connected to the DC bus. The dynamics related to current distribution can be controlled without impacting the voltage regulation. This decoupling is performed without resorting to a time-scale separation, which would lower the achievable performance. Instead, unilateral coupling can still be achieved by using a new control structure where the voltage regulation is independent of the current splitting. The proposed strategy, based on dynamic allocation theory, achieves a fast voltage response with an optimal current distribution among the converters, considering the current limits, the dynamic response, and the efficiency of the individual converters. The proposed solution is tested by numerical simulations in a Matlab/Simulink environment.