MPPT control of photovoltaic system using the two-mode IC method

This paper proposes the two-mode incremental conductance(IC) method for the maximum power point tracking(MPPT) control of a photovoltaic system. The conventional perturbation & observation(PO) and IC MPPT control algorithm generally uses fixed step size. A small fixed step size will cause the tracking speed to decrease and tracking accuracy of the MPP will decrease due to large fixed step size. Therefore, this paper proposes the two-mode IC method that has a variable step size control region and maximum step size control region according to operating conditions. To improve tracking speed and accuracy, when operating point is far from maximum power point(MPP), step size uses maximum value and when operating point is near from MPP, step size uses variable step size that adjust according to slope of curve. The validity of MPPT algorithm proposed in this paper proves through compare with conventional IC MPPT algorithm.