CONTROL OF A VARIABLE SPEED WIND TURBINE - INDUCTION GENERATOR SYSTEM

The problem of smooth control of electrical power from a large wind turbine generator to an electrical utility system grid is discussed. A speed control system is proposed which is applicable to either induction or synchronous machines asynchronously coupled to the grid through a controllable DC current link. A power limiting strategy is developed which spills power at high wind velocities without recourse to blade pitch control servomechanisms. The control strategy is simulated using modelled random wind-velocity sources as inputs.; The application of a variable speed induction machine to this wind power generation system is studied. A two axis induction machine model for controlled stator currents, including mutual inductance saturation effects, is developed. Induction machine capacitive self excitation phenomena are investigated. Excitation and torque control strategies are developed and simulated using both natural and forced commutated electronic power convertors.