2.4 Neural network MPPT controller architecture
The structure of multilayer feedforward networks are mostly
determined by experience, and according to previous studies
there is no valid formula that is appropriate for different
situations [13]. There are two methods of selecting the
architecture of the ANN techniques as in [13, 14]. The first
method begins with a small network and then proceeds by
gradually adding connections or nodes as needed. In the
second method, a big network is selected, and then proceeds
by gradually eliminating the unnecessary connections or
nodes. The first method was used in this study to map the
relationship between the duty ratio and the PV power and the
motor speed. Finally, after selecting an appropriate neural
network size, a satisfactory result was obtained with a three
layer feed-forward backpropagation neural network,
comprising (input, hidden and output layers) as shown in
Figure 3.