Abstract
This paper presents an Adaptive Neural Network Controller (ANNC) to control the speed of a photovoltaic (PV) supplied, separately excited dc motor driving a centrifugal pump load. The ANNC is also used to track the maximum power point (MPP) of the PV generator by controlling the converter duty ratio D. Since the controller has two tasks, then two objective functions must be existed. But to make the design of the controller easy and simple, the objective function related to the MPP is converted as a constrained to the other objective function by approximating some parts in the system. An Adaptive Neural Network Identifier (ANNI) is used to compute the system Jacobian, which is used to update the weights and biases of the ANNC. Both of the ANNC and the ANNI are trained on line using the BP algorithm with adaptive learning rate. Simulation results of the motor speed, current and voltage at steady sate operation are obtained for a step change in the insolation and reference speed (ωref) by two different cases depending on the calculation of the system Jacobian.
