Optimized DC motor output in a photovoltaic system

Dc motor drives normally operate from independent sources. Speed-control strategies are based on the premise of a constant-voltage source. A photovoltaic array provides a nonconstant voltage, especially if maximum power point tracking is employed to optimize the return of a high capital-cost investment. This situation requires different control strategies to adjust the motor´s characteristics, both to allow maximum power transfer from the source and to operate the motor at maximum efficiency. This problem is addressed and resolved in this paper for separately-excited dc motors. A further advantage with optimal control is a significant reduction of motor stresses.