Power Ramp-Rate Control via Power Regulation for Storageless Grid-Connected Photovoltaic Systems

TL;DR

This paper introduces a novel storageless, sensorless photovoltaic power ramp-rate control method that effectively manages power fluctuations without additional sensors or storage, validated through simulation and real-time experiments.

Contribution

It proposes a new PV PRRC approach controlling power directly, using a real-time curve-fitting algorithm, eliminating the need for irradiance or temperature sensors.

Findings

Effective power ramp-rate tracking demonstrated in simulations.

Comparable or improved performance over existing methods.

Validated through real-time hardware-in-the-loop experiments.

Abstract

Photovoltaic Power Ramp-Rate Control (PRRC) constitutes a key ancillary service for future power systems. Although its implementation through the installation of storage systems or irradiance sensors has been widely investigated, fewer studies have explored the power curtailment approach. The latter lacks efficiency, as it voluntarily produces power discharges, yet it is a cost-effective solution in terms of capital expenditures. This paper proposes a novel storageless and sensorless photovoltaic PRRC for grid-connected applications in which the photovoltaic power, rather than the voltage, is the controlled magnitude. The aforementioned contribution makes the effective tracking of the power ramp-rate limit possible compared to the existing methods in the literature. The method is assisted by a real-time curve-fitting algorithm that estimates the Maximum Power Point while operating suboptimally. Thus, no direct temperature or irradiance measurement systems are needed. The validation of the proposed PRRC strategy has been tested by simulation and compared to another approach available in the literature, considering real-field highly variable irradiance data. Experimental validation of the proposed strategy has been performed in real time via Controller Hardware-in-the-Loop.