A flexible active and reactive power control strategy for a variable speed constant frequency generating system

Variable speed constant frequency generating systems are used in wind power, hydro power, aerospace, and naval power generation to enhance efficiency and reduce friction. In these applications, an attractive candidate is the slip power recovery system comprising a doubly excited induction machine or a doubly excited brushless reluctance machine and PWM inverters with a DC link. A flexible active and reactive power control strategy is developed, such that the optimal torque-speed profile of the turbine can be followed and overall reactive power can be controlled, while the machine copper loss has been minimized. At the same time, harmonics injected into the power network has also been minimized. In this manner, the system can function as both a highly efficient power generator and a flexible reactive power compensator