The perturb and observe (P&O) algorithm is an easy and effective method used for tracking maximum power point. However, this technique suffers from deviation when irradiation changes suddenly. Moreover, the impact of this deviation is high when the insolation variation is rapid. This error is due to the incorrect decision taken by the conventional P&O method throughout the first step-change in the duty cycle during the increase in irradiation. The proposed P&O is a modified conventional P&O that focuses on using additional dI parameter with variable step size ΔDn. In this manner, the conventional P&O algorithm is allowed to identify the source of deviation caused by rapid irradiance changes. The efficiency of the proposed P&O is assessed using simulation in MATLAB/Simulink. Results show that the proposed P&O effectively tracks maximum power and prevents deviations in rapidly changing climate conditions within a short time, which is lesser than the conventional P&O method. In addition, the proposed P&O has a rapid dynamic response. A DC–DC boost converter is utilized in this work to validate the proposed P&O algorithm.