An Algorithm for Fast Flexible Power Point Tracking in Photovoltaic Power Plants

Abstract

Flexible power point tracking (FPPT) is control of active power generated by grid-connected photovoltaic power plants (GCPVPPs) to provide various grid-support functionalities, such as frequency response and voltage support. Fast transient response is required during grid voltage and frequency variations. An algorithm, based on dynamic voltage reference design and model predictive control for the dc-dc converter in GCPVPPs is introduced in this paper. The main novelty of the proposed algorithm is fast dynamic response based on the maximum capacity of the system. This feature enables fast FPPT operation in GCPVPPs. The proposed control algorithm results in several features for the FPPT operation, including: higher bandwidth, low power oscillations during steady-state, flexibility for adding constraints based on the operation conditions, and ease of implementation without requiring any complex control parameters tuning and design procedure. The transient performance of the proposed algorithm is evaluated under conditions of voltage sag and frequency deviation. Experimental results are also provided to demonstrate the effectiveness of the proposed algorithm when subjected to rapid changes in PV reference power.