Development of an Active Control System for a Variable Electromotive-Force Generator With Applications to Wind Turbines, Ships, and Hybrid Vehicles

An active control system is developed to adjust the overlap between the rotor and the stator of a modified generator, called a variable electromotive-force generator (VEG), based on the desired output power at different input speeds. A novel test stand for a VEG prototype, including a 700 W electric motor as the prime mover, a 12 V DC synchronous generator with an adjustable overlap between the rotor and the stator, and a stepper motor as an actuator for the active control system, is designed and fabricated. The national instrument LabVIEW platforms are used to perform the feedback control algorithm. In this paper, the performance of the VEG with an active control system to adjust the overlap between the rotor and the stator is studied theoretically and experimentally. The control algorithm can be expressed in discrete and continuous models to cover a broad range of applications of a VEG in wind turbines, ships, hybrid vehicles, and so on. The two goals of observing the increase in the generator rotor speed by decreasing the overlap between the rotor and the stator, and adjusting the overlap between the rotor and the stator based on a desired and optimum output voltage, were investigated in designing and implementing the active control system for the VEG.