This paper presents a modified maximum power point tracker (MPPT) for a standalone PV system. In this research a Particle Swarm Optimization (PSO)-based method is re-initialised by a variable step size (VSS) incremental conductance (IncCond) MPPT. The main motivation in this research is to eliminate the output ripple, and also to shorten the tracking time in rapidly changing insolation condition (RCIC). Used in this study, PSO-based method, precisely designed based on the dynamic behaviors of introduced system. The functionality of proposed method is evaluated by MATLAB/SIMULINK. Compared to IncCond method, the advantage of proposed one is that the PV outputs are more accurate and much less ripple-plotted. In comparison with standard PSO-based MPPT method, the tracking time in this method is much shorter, notably under RCIC.