A NEW PR-D (PROPORTIONAL RESONANT AND DERIVATIVE) CONTROLLER FOR RESONANCE DAMPING IN A GRID CONNECTED REVERSE VOLTAGE TOPOLOGY MULTI-LEVEL INVERTER

Renewable energy resources are connected to power grid through voltage source inverters. In these systems, the electric current entering into the grid is supposed to fulfill the IEEE criteria, so that high quality of power with less distortion is transported. Due to this, low pass filters like L, LC or LCL are applied by means of the inverter to minimize the harmonics getting into the grid. LCL filters are generally employed because of their functioning in filtering capability but they bring in resonance and unstableness. Therefore damping is carried out by applying controllers in the circuit to decrease the resonance in the system. In this paper, to suppress resonance, Proportional Resonant -Derivative (PR-D) controller is designed to check self-reliant action of proportional, resonant and derivative controllers. PR-D controller is compared with existing two degree of freedom controller (2DOF) and the system functioning is validated in a MATLAB platform. The simulation results exhibit that PR-D controller admits meliorate resonance damping & constancy when compared with the two degree of freedom damping. The performance of grid interfaced reverse voltage topology multi-level inverter with and without controllers is analyzed.