Power quality improvement through grid integration of renewable energy sources

Renewable energy sources (RES) are rapidly gaining popularity for sustainable power generation, they being less polluting and using readily available resources. This paper presents the modelling, control, and design analysis of a single-stage, three-phase RES-based distributed generation system where the grid-interfacing inverter is controlled to perform multi-functions by simultaneously incorporating active power filter (APF) functionality. The RES is connected to the DC-side of the voltage source inverter for interfacing with the grid. The inverter is utilized as power converter to inject the power generated from the RES to the PCC and shunt APF to compensate load current harmonics, load reactive power demand, and load current imbalance under distorted supply voltage conditions. Both these functions may be accomplished either individually or simultaneously. Thus, the designed controller either regulates the power flow between the RES and the grid or works as an APF or performs both the functions simultaneously. Simulation in MATAB and experimentation using DSP is carried out to verify the operation and the control principle.