An enhanced MPPT strategy for a grid-connected PV station under rapidly varying environmental conditions

Perturb & Observe (P&O) maximum power point tracking (MPPT) strategies need to sense and effect changes in PV voltage faster to keep up with changing power due to rapidly varying environmental conditions, and thus track the MPP accurately. However, the effectiveness of such P&O methods is limited in a grid-connected PV station scenario by the switching frequency of power electronic components. This paper proposes a novel, easy-to-implement MPPT strategy that improves performance even at low operating frequencies and under fast changing environmental conditions by exercising a greater control over the transient PV voltage. The proposed MPPT strategy has also been made adaptive to reduce the oscillations around the MPP. In addition a special provision has been made to circumvent the problems encountered by the traditional adaptive P&O algorithms for scenarios with constantly decreasing output power due to changing atmospheric conditions. The proposed MPPT strategy was tested in simulations and was observed to perform far better than standard adaptive P&O strategy.