Real-time digital control of DFIG-based wind generators for grid support

Abstract

In this thesis, a set of new converter /control techniques are developed for the Grid Side and Rotor Side converter applications in DFIG wind power generation. A real time digital simulation technique is also presented which is capable of studying in real time the performance of the DFIG wind power generator connected to grid. A number of practical control strategies for DFIGs are implemented and their performances are compared. Results show that a new improved direct power controller is able to provide very quick transient response for both the active power and the reactive power output from the DFIG wind energy conversion system. Extensive simulations and practical implementation of the algorithms on a digital controller embedded inside a digital signal processor are implemented. The hardware and software of the developed prototype DFIG control mechanism is described in detail in this dissertation. In addition, to study the effect of voltage sag and other types of transient disturbances and faults, a prototype of a fault generator using the same digital signal processor has been implemented. Effect of such disturbances on a transformer is investigated which is the nearest most probable location of a grid fault or disturbance.