An Improved Variable Step Size P&O MPPT Algorithm Based on Constant Voltage and K Division Technology

Abstract In the literature, various techniques have been proposed to achieve the maximum output power of photovoltaic cells, but the fixed step size perturbation and observation and incremental conductance algorithm can’t enhance effectively the peculiarity of the PV system, due to their slow tracking speed, big power loss and limited accuracy. An improved variable step size perturbation and observation MPPT algorithm based on the K division method is proposed. The symbol of dp/du before and after the disturbance is judged, if the two adjacent samples have the same symbol, the disturbance step size remains unchanged. On the contrary, the disturbance step size will be divided by K and become the new disturbance step size until achieving the maximum output power. The simulation establish on MATLAB/Simulink reveals that the method has fast response speed, high accuracy, low power loss, and can locate the new maximum power point quickly when environmental conditions change.