Modal analysis of tracking photovoltaic support system

Abstract

The tracking photovoltaic support system is a distinctive structure that adjusts its inclination to maximize energy yield and exhibits significant aeroelastic behavior, akin to long-span bridges and aircraft wings. Given the unique mechanical properties and aerodynamic effects of this system, wind loads play a crucial role in its design, as does a deep understanding of wind-induced dynamic effects. In this study, field instrumentation was used to assess the vibrational characteristics of a selected tracking photovoltaic support system. Using ANSYS software, a modal analysis and finite element model of the structure were developed and validated by comparing measured data with model predictions. Key findings are as follows. Dynamic characteristics of tracking photovoltaic support systems obtained through field modal testing at various inclinations, revealing three torsional modes within the 2.9–5.0 Hz frequency range, accompanied by relatively small modal damping ratios ranging from 1.07 % to 2.99 %. Additionally, we propose a finite element analysis method for modal analysis of tracking photovoltaic support systems, which yielded four torsional modes within the 2.8–7.0 Hz frequency range. The first three modes of this analysis closely align with field modal test results. The accuracy and applicability of the model were confirmed through a comparison of its predictions with the results of field modal testing on the tracking photovoltaic support system.