A Control Strategy with Series-Parallel Inverter for Micro-Grid Operation

Abstract

For the different operation mode of micro-grid, an improved droop control method and a parallel inverter was proposed depending on the study of micro-grid inverter. Grid-connected interface contains a series inverter and a parallel inverter, and can be switched to select different work mode. The parallel inverter can eliminate harmonic, compensate three-phase imbalanced current to improve the quality of the power delivered to the utility grid. In islanding operation mode, the improved droop control strategy was applied, where an integral controller was introduced. So it can reduce the inverter output voltage amplitude. Thereby it can restrain circulation and realize the power of self-distribution. The effectiveness and feasibility are verified by the simulation result.