Digital photovoltaic power conversion system with intelligent control approach

This paper presents the design and implementation of converters for grid-connected single-phase photovoltaic energy conversion system. In order to provide the functions of the energy management and the load distribution, the system is combined with the photovoltaic cells and utility network. Due to that the output voltage and current of the photovoltaic cells are easily changed by light and load fluctuations, it will cause the maximum power points drift. Therefore, the maximum power point tracking and power electronic technique are required to draw the available maximum power from the photovoltaic cells. The proposed system makes use of the perturbation-and-observation method to achieve maximum power point tracking. The output frequency, phase and amplitude of the single-phase inverter are the same with utility network by using the zero-crossing control method. A digital signal processor is applied for the system control. Finally, a 500 W generation system is constructed and tested to verify the system performance.