A variable frequency PWM rectifier for wind driven induction generators

This thesis presents a strategy to minimize the front-end converter rating for wind-driven Self-Excited Induction Generators (SEIG). Conventionally front-end converters need to handle complex power while the converter used in this strategy is able to function with rated real power. This converter is a variable frequency Pulse Width Modulated (PWM) rectifier. This strategy is made possible by the discovery of a formula for selecting the optimal static capacitor value, which along with the rectifier, provides the SEIG excitation current. In addition, a practical control scheme was developed which, combined with the excitation capacitance formula, works for isolated wind energy conversion systems. The presented research includes the analysis, simulation, and experimental verification of this novel strategy.