Sensorless Active Power Reserve Control for PV System with Low-Complexity MPP Estimation

To meet the requirements of modern grid, functional ancillary service such as active power reserve (APR) control has been essentially introduced in gird code with increase of photovoltaic (PV) systems. However, several limitations in previous APR methods, such as extra hardware, implement complexity and slow estimation speed, are demonstrated by approaching the maximum available power (P). Originated from the single-diode equivalent model and expression of PV current, the P could be estimated with any separated sampled pair of voltage and current in proposed control instead of direct measurement or estimation via curve fitting. With proposed control, the operation point during power curtailment are allocated at the left-hand side of maximum power point, where showed higher stability with a rapid change of surroundings. Furthermore, proposed APR control demonstrates a fast speed in P estimation, high robustness, and good compatibility with existing PV system, which will not increase the implement cost. Meanwhile, simulations and experimental evaluations under various conditions are carried out to verified the proposed control in this paper.