Control of a large scale single-stage grid-connected PV system utilizing MPPT and reactive power capability

A grid connected, three-phase, single-stage photovoltaic (PV) system has higher efficiency and simple power electronic converter topology compared to two-stage PV system. The control objectives such as maximum power point tracking (MPPT), synchronization with grid, current control, and harmonic reduction in output current are realized in only one-stage. This paper presents a high power, three-phase, single-stage, grid connected PV system with MPPT and reactive power injection capability into the utility grid. For current control, Park´s d-q transformation technique is used by using filtered three-phase grid voltage. A modified voltage controller using feedback linearization scheme with feed forward PV current signal is proposed to regulate the DC-link voltage. Reactive power feeding into the grid is also realized. To perform several simulations, PSCAD/EMTDC software environment is used.