Proposed control policy for high power transfer capability DFIG

This paper aims to extract maximum power from wind turbine at all permissible wind speed range while minimizing the total copper loss of the doubly fed induction generator (DFIG) simultaneously. A proposed steady state model is presented whereby unity rotor power factor (URPF) of the DFIG and wind-turbine MPPT variables are the state variables. The URPF proposed variable is the load angle (α) by which the generator performance characteristics can be controlled over the whole operating speed range. Comparison of URPF with conventional operation is given. This comparison illustrate and evaluate the generator performance characteristics at URPF operation up two twice synchronous speed. An analytical approach has been implemented to predict the optimal load angle and the speed dependent rotor voltage magnitude that insure MPPT at URPF. This speed dependent rotor voltage magnitude may be burnt into the EPROM of the digital reference generator provided by a rotor side converter in DSP system. Experimental results are given to strongly validate the proposed technique. Results have shown the DFIG as high power transfer capability (HPTC) transducer.