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 asses. 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.••Modal analysis of the solar tracking photovoltaic support system was conducted using field measurement and finite element simulation, and compared.••Field measurement torsional found deformation mode and dense frequency distribution in the low frequency range, with the second mode having a single nodal line and the third mode having two.••Modal analysis found torsional mode shapes and frequencies that matched measured shapes, with higher frequencies causing more torsional nodal lines and structural damage.••Field measurement and finite element simulation had 4% max error and stron. Tracking photovoltaic support systemTorsional vibrationModal analysisField measurementTracking photovoltaic support systems utilize mechanised tracking support to adjust the orientation of photovoltaic modules. The angle between direct sunlight and the modules is minimized which improves energy yield efficiency and produce greater economic benefits. As a result, solar tracking support technology has been extensively employed in the domain of solar photovoltaic power generation. When the tilt angle of the tracking photovoltaic support system changes, the mass and stiffness distribution of the whole structure change correspondingly. Since the photovoltaic panels of the tracking photovoltaic support system have different tilt angles, changes of its natural frequencies and mode shapes under different tilt angles should be considered during modal analysis.Tracking photovoltaic support systems (Fig. 1) are usually built in the form of large photovoltaic arrays. To maximize energy yield, most solar farms are located on flat open terrains with direct sunlight. However, under such conditions, the panels are vulnerable to strong winds. The longitudinal length of the tracking photovoltaic support system is large. Powered by motors, the photovoltaic panels rotate about the longitudinal axis bar. To reduce friction, bearings are used at the support. Structurally, the tracking photovoltaic support system can be regarded as a single-degree-of-freedom (single axis rotation) s. 2.1. Brief introduction of module prototype of tracking photovoltaic support systemThe tracking photovoltaic support system (Fig. 1) is mainly composed of an axis bar, PV support purlins, pillars (including one driving pillar in the middle and nine other non-driving pillars), sliding bearings and a driving device. The axis bar is composed of 11 shaft rods. Photovoltaic panels are installed on the photovoltaic support purlins. The reciprocating rotation (tilt angle) of the axis bar allows the panel to receive direct sun. The structure is symmetrical with respect to the axis bar, and the axis bar provides a fixed axis for torsional deformation. The axis bar is supported by pillars, which can prevent the horizontal and vertical movement of the structure. The driving device is installed on the driving pillar, utilizing a single point independent drive rotation mode. Mechanical transmission is then achieved through sliding bearings on the upper parts of other pillars. The total length of each module of the tracking photovoltaic support system in the present study is 60.49 m, and each module is composed of 52 photovoltaic panels. Each photovoltaic panel measured 2256x1133x35mm, as shown in Fig. 2.2.3. Modal measurement arrangement and working condition.
