Current THD Analysis of Model Predictive Control based Grid-Connected PV Inverter

Abstract

Designing a controller for a grid-connected inverter is a difficult task due to intermittent photovoltaic (PV) source which is connected to the input of the inverter. Inappropriate operation of the inverter produces high total harmonic distortion (THD) in the output current. This causes a significant amount of power loss and thus less power penetration to the grid. Hence, a predictive current control (PCC) based grid-connected inverter for penetrating more PV power to the ac grid is presented in this paper. The PCC selects an optimized switching signal based on a predefined cost function and thus provides a lower current THD. The existing controllers such as proportional-resonant and selective harmonic elimination are also simulated for the same parameters and compared to the proposed controller. To verify the effectiveness of the controller, the reference current of the controller is also varied in a wide range and tested for current THD. Simulation results show that the proposed PCC yields lower current THD than the existing controllers.