Multi-functional power converter building block to facilitate the connection of micro-grid

This paper presents a structure of modified DC bus interconnected single-phase micro-grid, as well as a topology of power converter building block (PCBB) based on the DC bus to perform various functions in a distributed energy network. The main functions of the PCBB are: compensating the current harmonics produced by nonlinear load in the micro-grid, mitigating the voltage sag or swell of the electrical power system (EPS) at the point of common coupling (PCC) and facilitating the islanding and re-closure of micro-grid when a severe fault happens to the EPS. To enable the PCBB to work efficiently and effectively, a synchronous rotating frame (SRF) based 6n^th order high bandwidth controller is applied to control the current harmonics compensation; a cascaded PI controller is used to regulate the voltage sag/swell compensation. A complete set of simulation results will be given to validate the viability and efficacy of the PCBB in inter-connecting the modified DC bus interconnected micro-grid.