Fast Power Point Tracking of Two-Stage Photovoltaic System based on Polynomial Approximation

With a higher solar power penetration level, more advanced power control functionalities are integrated into grid codes for photovoltaic (PV) systems, such as frequency support. The fast power tracking point (FPPT) technique enables PV systems to respond to the power command in a desired time. In this paper, a new FPPT algorithm for two-stage PV systems based on polynomial approximation is proposed. By mathematic analysis on the right-side power-voltage (P-V) characteristic of PV panels, a suitable polynomial approximation is used to derive the preset value of PV panel voltage reference so as to improve the tracking speed. In final, case studies using EMTP-RV simulator are carried out, simulation results validate the proposed algorithm in terms of fast dynamic and high accuracy compared with existing methods.