Predictive Control of Three-Level Boost and T-type Converters with Constant Switching Frequency for Photovoltaic Energy Systems

This paper introduces a novel two-stage power conversion architecture tailored for grid-connected three-phase photovoltaic (PV) systems. The proposed configuration employs a three-level (3L) boost converter in conjunction with a 3L T-type inverter, each assigned distinct control responsibilities to improve power quality delivered to the grid. The boost converter is tasked with regulating the DC-link capacitor voltage and executing maximum power point tracking, thereby simplifying the inverter's control demands. A deadbeat current control strategy governs the boost converter, while a modulated model predictive current control approach is applied to the inverter. These techniques are implemented within a dual-loop decoupled control structure that ensures fixed switching frequency, reduced steady-state errors, and enhanced dynamic responsiveness. The effectiveness of the proposed system is assessed through simulations of a 120 kW PV array under varying solar irradiance and temperature conditions. Results demonstrate the system's capability to maximize solar energy utilization and maintain grid compliance with high power quality through precise and independent control of each stage.