Optimization of Solar Photovoltaic Water Pumping System during Monsoon Conditions

This paper addresses the problem of solar photovoltaic water pumping during monsoon weather conditions for domestic and small scale agricultural purposes. Since solar radiation varies rapidly during monsoon conditions, a variable speed water pumping system could be a possible solution for this problem. For fixed head applications, the speed variation should be done in such a way that the maximum power should be extracted from solar panel without affecting the head of the water pumped. This paper proposes a variable speed water pumping system, using a Brushless DC (BLDC) motor which gives better efficiency compared to that of induction motor and also reduced maintenance requirements over brushed DC motors. Moreover, BLDC motors offer excellent speed-torque characteristics; high torque to size ratio, high starting torque, lower acoustic noise and electromagnetic interference, long operating life and simpler constructional feature which make them well suited for low power solar water pumping applications.