Digital PI current control for grid connected PV inverter

This paper describes a digital proportional-integral (PI) control method for single-phase grid-connected photovoltaic (PV) system. The control algorithm is implemented in digital signal processor (DSP) TMS320F2812. A detail analysis of system control and mathematic formation of digital PI control is presented to show that this control method provides robust current regulation and operates at near to unity power factor. The PI current control method is implemented in a single-phase grid-connected PV inverter to convert DC power from the solar modules into AC power to be transferred to the grid. Simulation and experimental results are provided to demonstrate the effectiveness of the design.