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.