Zero-oscillation adaptive-step solar maximum power point tracking for rapid irradiance tracking and steady-state losses minimization

This paper develops the theory for an adaptive Maximum Power Point Tracking (MPPT) strategy to reduce extraction losses and other issues typically introduced by Perturb and Observe (P&O) algorithms. Three techniques to improve steady-state behavior and transient operation are discussed in detail: 1) idle operation on the Maximum Power Point (MPP), 2) irradiance direction change identification and 3) multi-level adaptive tracking step. As a result, these strategies are combined to achieve superior overall performance while maintaining a simplicity of implementation. Two key elements which form the foundation of the techniques are discussed: the suppression of perturb oscillations at the MPP and the indirect identification of irradiance change through a current-monitoring algorithm. The Zero-oscillation, Adaptive-step Perturb and Observe (ZA-P&O) strategy is studied with simulation and validated with experimental results. The mechanism for power extraction gains is evident, making the combined techniques an excellent solution to enhance MPPT performance.