AC-Type Digital-Power-Communication Concept for Multiconverters Information Interaction in AC Microgrids

Abstract

By multiplexing the inner auxiliary power supply of each converter as a communication carrier, an ac-type digital power communication (ac-DPC) concept based on the “power talk” is proposed to realize the multiconverters information interaction in ac microgrids. From the perspective of power and information controllability, the communication mechanism of ac-DPC is analyzed, and two different topologies based on single-stage boost-flyback circuits are deduced. Moreover, it is found that the signal strength of ac-DPC is limited at the ac-voltage zero crossing point (ZCP). The essential reason is revealed that the communication current amplitude cannot be regulated at the ZCP due to its unidirectional structure and the coupling relationship of communication current to ac voltage. Therefore, by introducing a communication compensation module, the ac-DPC topology II is further proposed to eliminate the adverse effect of the ac voltage. In addition, an ac-DPC energy and information integrated control method is proposed to realize the dual functions of auxiliary power supply and “power talk” and ensure the signal strength at the ZCP. Finally, the experimental platform based on ac-DPC is developed, and the experimental results verify the feasibility of ac-DPC and the effectiveness of the proposed control method.