As photovoltaic (PV) power generation being a core energy source in new power systems, it is crucial to improve its the efficiency. The solar tracking technology is an effective means. However, existing solar tracking control strategies of both the open-loop and closed-loop have significant limitations, of which the open-loop is prone to cumulative error while closed-loop control is costly and requires complex maintenance. In this paper, a novel sensor-free closed-loop solar tracking control strategy is proposed to overcome the dependency on external sensors in conventional closed-loop systems. An analytical relationship between the PV panel’s altitude and azimuth angles and the maximum power output of the internal Maximum Power Point Tracking (MPPT) controller is firstly derived. By continuously adjusting the altitude and azimuth angles based on the output power from the MPPT controller, the system achieves precise closed-loop solar tracking. Additionally, a step-size attenuation factor is introduced to accelerate convergence and reduce local oscillations. Experimental results demonstrate that the improved sensor-free closed-loop control strategy achieves faster tracking with a tracking error of less than 0.05°, while also being cost-effective and durable. The proposed strategy offers a promising solution for enhancing the practical efficiency and stability of solar tracking systems.
