Harnessing maximum power from solar PV panel for water pumping application: A simple approach

Abstract

Among alternate sources of electricity, solar photovoltaic (PV) energy is gaining prominence due to its plentiful availability. Water pumping is an important application of solar PV power. However people are not opting for it in large numbers as "cost per watt" for solar pumping systems is high and the reliability is poor due to complex technology. The cost can be reduced by harnessing more power per unit installed capacity of the solar panel. One of the methods of realizing this is by Maximum Power Point Tracking (MPPT) wherein a power electronic converter is used to match pump with the PV panel. Currently "panel power" is the widely employed control parameter for MPPT. This approach can be referred to as MPPTPP. Present paper proposes load voltage as control parameter for MPPT. Varying the duty cycle of the MPPT converter such that load voltage is always maximum leads to harnessing maximum power output. This approach can be referred to as MPPTLV. Here only one parameter i.e. load voltage needs to be monitored. MPPTLV is simpler than MPPTPP as in the latter case it"s necessary to measure both panel voltage and current and then find their product. The proposed method is substantiated by theoretical explanation followed by simulation as well as experimentation results. The system considered is a standalone PV source connected to Permanent Magnet (PM) brushed DC motor driving centrifugal pump.