A state of the art review of control techniques for power electronics converter based distributed generation systems in different modes of operation

This paper presents an overview of the state of the art techniques in inverter-based distribution generation systems. Different control techniques and classification of inverter modules operated in grid and islanded modes are investigated. The merits and drawbacks of each technique are presented. The operation of the inverter is classified into, single and parallel operation. Parallel operation is used to increase the reliability but some techniques require communications links between the inverter modules. The problem of circulation current between different parallel inverters is investigated.