Proportional Resonant Control of Power Electronic Interface for Integrating Renewable Energy Sources

Abstract

Power electronic converters are commonly used to interface renewable energy sources. There exist several topologies of these converters such as two level with LCL filter, multilevel, matrix and interleaved. This thesis focuses on two level LCL filter based topology which is commonly used in grid connected applications. To meet national international standards, there is requirement of suitable control strategy. It is an active area of research which has been investigated in this thesis. Proportional Resonant Controller has been identified as a good candidate for said application. Its performance has been tested under different conditions especially system bandwidth. Moreover comparison with classical controller has been presented as well. The classical PI controller is found to be robust and able to provide high stability margins under varying load impedance however at the same time it has high harmonic content in the output current. Proportional Resonant controller is found to be adequate as it is able to provide low total harmonic distortion in the output current as compared to PI controller. Simulation results shows that proposed controller can provide better stability margins to the system, ability to attenuate grid harmonics and good robustness by carefully selecting the capacitor and inductor values in LCL filter as compared to PI controller.