Abstract
Single-stage grid-connected PV systems provide many advantages such as simple topology, high efficiency, high power density, and lower cost. However, achieving MPPT, while conditioning the output power and synchronizing with the power grid, is a big challenge in such systems. In this paper two MPPT schemes are investigated for single-stage three-phase grid-connected photovoltaic voltage-source inverters. MPP is tracked using either the load angle or the inverter modulation index.
A theoretical framework of the schemes is provided. Furthermore, a simulation model is developed in MATLAB Simulink and the simulation results are presented in this paper. Then the schemes are implemented using a fixed-point digital signal processor (DSP) TMS320F2812. Moreover, a breadboard circuit is built-up for investigating the effect of the proposed schemes on MPPT in a single-stage three-phase grid-connected photovoltaic voltage-source inverter. Furthermore, a comprehensive discussion is carried-out to evaluate the performance of each scheme.
The experimental results show that both schemes can track the maximum available power of the PV. Furthermore, a hybrid scheme that employs both schemes may be a good compromise to attain efficient dynamic and steady state performances.