Energy management for linear and nonlinear loads in distributed power system consisting of inverters

ABSTRACTPh.D. ThesisENERGY MANAGEMENT FOR LINEAR AND NONLINEAR LOADS INDISTRIBUTED POWER SYSTEM CONSISTING OF INVERTERSKoray Şener PARLAKFirat UniversityGraduate School of Natural and Applied SciencesDepartment of Electrical and Electronics Engineering2006, Pages: 117Power sharing in microgrid systems consisting of two inverter units has been investigated inthis dissertation. The control algorithm which uses the load-frequency droop concept ensures that theinverters with different ratings share the total load in proportion with their ratings. As the controlalgorithm utilizes only the output variables of each inverter, no data transfer between the units isnecessary. This enables distributed operation of the system.Power sharing of the system has been simulated and experimentally verified for active andreactive power, both at the same time and separately. The results are in good agreement.A control algorithm that is based on expressing the nonlinear load related harmonics onsynchronous reference frame and then eliminating them has also been developed in this dissertation.By using this control algorithm along with the load-frequency droop technique load sharing has beenachieved in the microgrid. Thus, continuous power flow, distributed operation and power quality havebeen obtained through parallel operation, load sharing, optimal operation of inverters and harmonicelimination.Keywords: microgrid, distributed operation, power quality, load-frequency droop, load sharing,parallel operation of inverters.