Performance Analysis of Model Predictive Controller for Grid-Connected Quasi Z-Source and Split-Source PV Inverters

Abstract

This paper studies the performance of a model predictive controller (MPC) on quasi Z-source and Split-Source single-phase on-grid inverters. Quasi Z-source inverter (qZSI) and Split-Source inverter (SSI) are transformer-less single-stage inverters which are proposed to replace traditional two-stage inverters. Both topologies suffer from large low-frequency ripples on passive elements in the open-loop control condition. By deriving precise discrete mathematical equations, MPC is designed and proposed, to control qZSI and SSI with the aim of decreasing THD of grid current and input current ripple as well as suppressing low-frequency ripples. The performances of designed systems are studied in MATLAB/Simulink and the results are presented. By integrating the PV array to the system, maximum power point tracking (MPPT) is investigated in the current-based method. Also, by proposing a new approach, voltage of PV array in the MPC controller is predicted and consequently, a high-efficiency MPPT is achieved utilizing the voltage-based method.