Framework of Digital Twin Based on State Space Model for Stability Assessment of 2-Stage 3-Phase Grid Connected PV System

Abstract

The growing incorporation of power electronic converter-based renewable energy sources, such as solar Photovoltaic (PV) systems, has introduced a new challenge to grid stability due to the complex control dynamics and intermittent nature of sources. In this article, an innovative stability monitoring approach based on Digital Twin (DT) technology is presented for a two stage three phase grid connected photovoltaic system. A DT using concept of state space model is developed for a two stage three phase grid connected photovoltaic system based on mathematical model using Tustin transformation. A newly developed Discrete Damping ratio Adaptation Second Order Generalized Integrator-Frequency Locked Loop (DDASOGI-FLL) based Sliding Mode-Model Predictive Control (SM-MPC) and Adaptive Golden ratio based Electromagnetic Field Optimization (AG-EFO) algorithm are used for optimal performance of the entire system. Furthermore, the stability of the system and control are monitored periodically based on developed DT using the direct Lyapunov stability method. The stability assessments are conducted under various dynamic conditions such as unbalance & disturbance in grid voltage and irradiation change. To validate the accuracy of the developed DT and control strategies, a laboratory-based experimental prototype is developed.