This thesisis concerned with controlling active power in distributed generation units in a microgrids using adaptive droop characteristics. Nowadays the level of global warming is increasing and therefore the use of renewable energy resources has become very attractive due to their green and non-polluting nature. Consequently, renewable energy-based distributed generators based on solar and wind energy are playing a dominant role in electricity production and will gain considerable importance in the near future. A microgrid consists of clusters of distributed genrators and loads that operate as a single controllable system. The power generated by some of distributed generators depends on electrical conditions and can be controlled by the system operator. The power generated by these distributed generators can be changed on the basis of electric conditions or load demand. These kind of distributed generators are called dispatchable units. On the other hand, the power generated by other distributed generators, such as solar cells and wind turbins, depends on non electrical conditions like weather conditions. For example the power output from photovoltaic cells may vary during the day on weather conditions. The power generated by this group of distributed generators is variable and can not be controlled by system operator. These type of energy sources are called non dispatchable distributed generators. In this thesis, the concept of microgrid and distributed generation is illustrated. Distributed generators will be divided into dispatchable and non dispatchable units and the properties of each gorup are briefly described. A microgrid can operate in two different modes: islanded (or standalone or autonomous) mode and grid connected mode. In islanded mode, the controller of energy resources not only controlls the voltage and ferequency of the system but also properly shares the microgrid load among energy resources. One common way to share active and reactive power between energy resources in microgrid is using droop charachteristics. In grid connected mode, energy resources are usaully controlled to generate given amounts of active and reactive power. In other words, energy resources in grid connected microgrids are usually preferred to operate in PQ mode. Keywords: Distributed generators, dispatchable distributed generators, non dispatchable distributed generators, Microgrid, load sharing, conventional droop characteristic, adaptive droop characteristic.