Small signal stability analysis of photovoltaic array based on averaged switch modeling technique

Grid-connected photovoltaic (PV) generation is becoming more attractive and finding increased use due to the many advantages of using renewable energy sources in the future grid. As the penetration of the PV array in today’s grid increases, the impact of this new clean source on the stability of power system needs to be well-understood. This work presents a general configuration of grid-connected PV array including boost converter and voltage source inverter. For the sake of power system study, averaged switching models of power electronic devices are replaced by exact model. Then, the behaviors of both models are compared under the same control strategy against the changes in ambient conditions. Furthermore, a set of non-linear state space equations based on average switching technique are derived and implemented as matlab scripts. Assuming small variation in input signals, the nonlinear model is linearized around the equilibrium point and the linearized state matrix is presented. Then, the modal analysis is conducted which revealed the participation of controllers’ parameters in system modes. Ultimately, based on some valid assumptions, the simplified model is introduced and its behavior was compared with non-linear and linearized model.