Fractional Order Modelling and Analysis of Utility Grid Connected and Autonomous Modes for Distributed Power Generation

The fractional order modelling of a power electronic converter using a two-level voltage source inverter (VSI) in utility grid connected and autonomous modes are analysed in this paper. Fractional order modelling is expressed in the synchronous rotation coordinate system by using transformation theory. The effectiveness of fractional order models is confirmed by mathematical modelling and simulation results, which show that Fractional order models can more accurately describe the operating characteristics of two level VSI. As compared with traditional integer order, Fractional order inductor and capacitor can provide better static and dynamic performance, such as time domain and frequency domain analysis for utility grid connected mode and autonomous mode of operation. The FOMCOM toolbox in MATLAB/Simulink is used to build UGCM and AM simulation models and analyse their performance. The presented work implies performance and stability improvement of system in all operating modes using fractional order modelling in time and frequency domains respectively. Further this work will promotes design of controllers for closed loop operation of converters in AC microgrid.