Enhancement of Photovoltaic Systems with Cascaded Modular Multilevel Converters Using Fuzzy Controller

Abstract

The penetration of photovoltaic (PV) solar power generation in distributed generation (DG) systems is growing rapidly. This condition imposes new requirements to the operation and management of the distribution grid, especially when high penetration levels are achieved. Under this scenario, the power electronics technology plays a vital role in ensuring an effective grid integration of the PV system, since it is subject to requirements related not only to the variable source itself but also to its effects on the stability and operation of the electric grid. This paper proposes an enhanced interface for the grid connection of PV solar systems. The relationship between output voltage components of each module and power generation is analyzed with the help of a newly derived vector diagram which illustrates the proposed power distribution principle. On top of this, an effective control system including active and reactive components extraction, voltage distribution and synthesization, is developed to achieve independent active and reactive power distribution and mitigate the aforementioned issue. Finally, a 3-MW, 12-kV PV system with the proposed control strategy is modeled and simulated in MATLAB. Simulation and experimental results are provided to demonstrate the effectiveness of the proposed control strategy for large-scale grid- connected cascaded PA full detailed model is described and its control scheme is designed. The dynamic performance of the designed architecture is verified by computer simulations and Further Extension can be done using Fuzzy Logic Controller.