A double-linear approximation algorithm to achieve maximum-power-point tracking for PV arrays

In this paper, a double-linear approximation algorithm (DLAA) to achieve maximum-power-point tracking (MPPT) for PV arrays is proposed. The DLAA is based on that the trajectories of maximum power point varying with irradiation and temperature are approximately linear. With the DLAA, a maximum power point can be determined instantaneously. Moreover, complicated calculation and perturbation about an optimal point can be avoided. In the paper a corresponding circuit to complete DLAA is proposed as well, of which configuration is simple. As a result, the proposed circuit is cost-effective and can be embedded into PV arrays easily. An implementation example of PV power system with the proposed MPPT is designed and the DLAA is compared with the perturb-and-observe method. From simulated and experimental results, the proposed MPPT algorithm has been verified and the feasibility of the proposed circuit is also demonstrated.