Distributed Generation System with Hybrid Inverter Interfaces for Unbalanced Loads

Applications of 4-leg inverter are found not only in active and unbalanced load compensators but also as an interface for transferring power generated by renewable energy sources in distributed generation system and microgrids. However existing distributed generation systems commonly use 3-leg inverters. In this paper, the possibility of using a 4-leg inverter interface along with the existing units with 3-leg inverter is explored. This forms the distributed generation system with hybrid inverter interfaces and is studied in detail in presence of unbalanced loads. Analysis of a hybrid system is presented in respect of sequence component analysis of terminal voltages. It is shown that if the expected unbalanced loads are fed from the 4-leg inverter side, the performance of the system is improved in respect of negative and zero sequence components in terminal voltages.