华南理工大学 机械与汽车工程学院/广东省汽车工程重点实验室，广东 广州 510640

关键词: 车载光伏系统, 气动性能优化, 净功率

Abstract:

The present study examines the state of research on vehicle-mounted photovoltaic systems, with a particular focus on the optimization of photovoltaic panel installation area. The research explores the potential for enhancing power generation by optimizing the folding mechanism of the panels. However, the study's scope does not extend to the synergistic optimization of power generation and the additional drag energy consumption of the system. The objective of this paper is to enhance the net power of vehicle-mounted photovoltaic systems. The proposed methodology involves optimizing the aerodynamic performance of these systems. This approach is expected to reduce the drag energy consumption of the system relative to the vehicle, thereby enhancing the net power of the system. In the initial phase of the project, the vehicle-mounted photovoltaic (PV) system, in its folded state, was designated as the object. The aerodynamic high transmittance fairing and the tail wing of the PV system were then designed. Subsequently, three design variables were selected for optimization: the front tilt angle of the fairing, the back angle, and the height of the system. These variables were hypothesized to influence the aerodynamic drag through the construction of an orthogonal experimental table and the use of the analysis of the polar deviation. The system drag, front tilt angle, and back angle are all found to have a monotonic influence on the system aerodynamic drag, as evidenced by the analysis of the main effect plot. In the primary effect plot analysis, the three parameters exhibit monotonic effects on the aerodynamic drag of the system. The structural parameters of the fairing shape are as follows: the forward inclination angle α is 70°, the back angle β is 0°, and the height of the system h is 100 mm. Subsequently, the tail angle of attack of the vehicle-mounted photovoltaic system is optimized, and a three times spline interpolation approximation model is constructed on the experimental data to obtain the optimal tail angle of attack of the lift-to-drag ratio of 33.96°. In comparison with the vehicle equipped with the onboard photovoltaic system that is the subject of this study, the Cd value is reduced from 0.619 to 0.343, representing a 44.59% decrease. Furthermore, the aerodynamic drag is reduced from 484.26 N to 375.56 N, indicating a 22.44% decrease. Additionally, the Cl value is reduced from 0.The range of values from 065 to -0.082 indicates a 226.15% decrease, and the direction of the lift undergoes a transformation from upward to downward. This adjustment serves to mitigate the adverse impact of upward aerodynamic lift on the handling and safety performance of the entire vehicle. A comparison of the original vehicle model with the modified version reveals a significant reduction in Cd value from 0.415 to 0.343, marking a 17.35% decrease. Concurrently, aerodynamic resistance undergoes an increase from 372.42 N to 375.56 N, representing a modest 3.14 N rise. This adjustment effectively mitigates the adverse effects of the onboard PV system on the vehicle's aerodynamic performance. Finally, a comparison and analysis of the net power of the on-board PV system before and after optimization is conducted, revealing a net power difference of 7723.62 W at a vehicle speed of 40 m/s.

Key words: on-board photovoltaic system, aerodynamic performance optimization, net power