Comprehensive Modelling and Small Signal Stability Analysis of RES-based Microgrid

Implementation of power electronic devices has introduced novel challenges in microgrid (MG) operation and control; and hence the condition of power electronic devices should be monitored for stable operation of the entire grid. This paper presents detailed small signal model of the MG based upon Renewable Energy Resources (RESs), focusing on the dynamic behavior of power electronic devices and associated controllers. Variations on inverter modulation indices and boost converter duty cycles were applied to observe small signal stability performance of the MG. Eigenvalues and participation factor analysis were presented to identify weak modes and stability margin. Analysis of eigenvalue loci shows motion of low frequency loci toward the right-half complex plane as the parameters of power electronic devices varied. More severe oscillatory behavior was experienced when fluctuation occurred at the grid-side inverter, which indicates fast degradation of damping and stability margin. The presented work contributes to help utilities in designing a stable MG for seamless integration of renewable energy into power systems.