MULTIFUNCTIONAL CAPABILITIES OF GRID CONNECTED DISTRIBUTED GENERATION SYSTEM WITH NON-LINEAR LOADS

This paper deals with the integration of distribution energy resource (DER) connected to a three-phase grid connected system feeding a variety of loads. The DER is controlled to provide power quality improvement capabilities viz. power factor correction, harmonic reduction, voltage regulation, and load balancing, and it is realized as a voltage source converter (VSC). The developed controller is based on Synchronous Reference Frame (SRF) Theory and an energy based controller that also includes additional features viz. filtration of fundamental voltage extracted from the polluted utility grid voltages. This new controller, realized as an energy controller, is implemented over the square of the DC link voltage of the DER. The control algorithm has been tested for several power quality improvement features and works well for power factor correction, voltage regulation, harmonic reduction, and operation under unbalanced load conditions. Extensive simulation and hardware results are demonstrated on a prototype developed in the laboratory.