Robust Design of Perturb & Observe Maximum Power Point Tracking for Photovoltaic Systems

The perturb & observe (P&O) maximum power point tracking (MPPT) is widely used in photovoltaic (PV) systems due to its simplicity and reliability. To optimize the performance, a tradeoff between static and dynamic efficiencies should be made. Yet, present design methods are not efficient enough for practical use. As for the prior-art calculation-based methods, they only focus on the problem of direction confusion under dynamic conditions, while the static efficiency will be low. Although the experience-based methods consider both static and dynamic efficiencies, they cannot give a clear result, and the parameters still need to be set in a trial-and-error process. As such, in this paper, an analytical model is established based on the operation principles to provide clear characteristics of key indices (i.e., static and dynamic efficiencies, and the requirement of the DC voltage range), and the impact of parameters on the efficiency is revealed. Subsequently, a robust design is proposed for the optimum design, which can set the key parameters, achieving relatively high tracking accuracy. Finally, simulations and experimental tests are performed, verifying the theoretical analysis and the effectiveness of the proposed design.