Three-Phase Inverter Parallel Droop Control

In this paper, the inductive output impedance of inverters parallelized in an islanded microgrid is investigated. A wireless load equalization control method for inverter islanded parallel connection in AC distributed systems is implemented. The control loop is designed and analyzed for the characteristics of low voltage microgrids in which the distance between inverters is long and it is difficult to realize control interoperability. The controller employs droop control to obtain a more optimal control strategy compared to the conventional droop control method. The controller is implemented through the use of a digital signal processor board that uses only local three-phase AC unit signal measurements, thereby increasing the modularity, reliability and flexibility of the distributed system. The characteristics of the proposed wireless control method are verified through parallel experiments with two 4 kVA inverters.