An Efficient Modeling Technique to Simulate and Control Submodule-Integrated PV System for Single-Phase Grid Connection

The photovoltaic (PV) system that is based on submodule-integrated converters (subMICs) is capable of maximizing solar energy harvest by eradicating power losses due to intrapanel mismatch. Modeling and simulation of subMIC-based systems are important to study the effect of PV partial shading, prove new control strategies, analyze distributed system dynamics, optimize system configurations, and determine system parameters, etc. However, the simulation of such systems can be very challenging due to the large number of switching-mode power units, nonlinear nature of PV generators, and complication of the coordinating control. This paper provides an effective solution to simulate and control single-phase grid-tied PV systems that are based on a practical subMICs configuration. The approach includes the simplified PV cell model and averaged model for power converters, which consider all dynamic interactions among the maximum power point tracking (MPPT), PV submodule voltage regulation, dc-link voltage control, and double frequency ripple. The effectiveness of the proposed simulation and the sub-MIC system is validated by the comparison with a practical system based on centralized PV inverter under the real-world solar irradiance and various PV mismatch conditions, e.g., partial shading and uneven temperature distribution etc.