The Control Strategy Of Three-Phase PV Grid-Connected System

In recent years, there has been an increase in the use of renewable energy due to the growing concern for the pollution caused by fossil-fuel-based energy. Therefore, the use of renewable energy has become the new focus of the study of mankind. The solar energy and renewable energy an important and utilization, with inexhaustible and will not pollute the environment and damage the ecological balance and so on.In this paper, we discuss the three-phase photovoltaic grid-connected system control strategy. First of all, according to the solar cell output characteristics, and established a mathematical model and introduced the more classic variety of the current maximum power point tracking (MPPT) method which carried out by MATLAB simulation. Secondly, analyse the three-phase photovoltaic grid-connected inverter topology and control principle. This paper discusses the work of three-phase full-bridge inverter based on the principles of established law based on space vector pulse-width modulation (SVPWM) algorithm. By analyzing the d-q coordinate system the L-filter three-phase grid-connected system mathematical model of the d-q coordinate system, described its decoupling methods, and for the PI controller in stationary coordinate system to track sinusoidal command can not be completely achieve zero steady-state error problem proposed outer ring voltage-current inner ring of the double-loop control strategy. Through MATLAB and related experimental verified the correctness of this method. Finally, a brief analysis the space vector (SVPWM) method of the theory and hardware implementation, through a comparison of several other inverter strategy, highlighting the advantages of this inverter strategy.To sum up, this paper by analyzing the two-phase grid-connected photovoltaic power generation and single-stage grid advantages and disadvantages, summarized the two kinds of different control strategies, with emphasis on control strategies carried out the simulation study, through the relevant experiment to prove the correctness of this method.