Stability analysis of grid-connected photovoltaic systems using a linear zero dynamic controller

This paper proposed a new linear zero dynamic controller (LZDC) for three-phase grid-connected photovoltaic (PV) systems. To implement the controller, the PV is modeled in dq frame which is obtained from park transformation. In order to analyse the stability, the PV system is linearised about an operating point by using Taylor series expansion method. Here the relative degree is investigated through the concept of Lie derivatives to execute the LZDC. To implement the control theory, the stability of the system is also analysed. Finally the linear control law is obtained and implemented on a three-phase grid-connected PV system to control the current injected into the grid through the inverter of the system. The system has been simulated to demonstrate the effectiveness of the proposed scheme.