New Single Current Sensor Based Variable Step Size MPPT for Stand-alone Battery Storage PV Systems

摘要

To extract the maximum Power from the photovoltaic (PV) energy system, the real time maximumrnpower point (MPP) of the PV array must be tracked closely. Furthermore, to decrease the cost of thernPV energy system, a minimum sensing requirement algorithm is needed. From this base, this paperrnproposes two methods of variable step size maximum power point tracker (MPPT) using single currentrnsensor for battery storage PV systems. Both of them receive the PV module current as the input variable.rnIn the first method, the updating rule of the variable step size depends on the derivative of [(1-rnD)I_(PV)] with respect to D, where D, I_(PV) correspond to the converter duty cycle and the PV model current,rnrespectively. However, in the second method, the updating rule of the variable step size depends onrnthe absolute difference between two successive instants of [(1-D)I_(PV)]. A comparative study has beenrnheld between the two method in order to investigate their capabilties to improve both the transient andrnsteady state responses as well. The esperimental validation of the varibale step size MPPT has beenrnverified using field programmable gate arrayes FPGA.