The authors propose using the inductor generator with electromagnetic excitation in a wind-hydrogen independent power system for generation of the base load. They show that the remanent magnetic flux in such a generator is unable to create the electromotive force sufficient for its excitation from the cold start. This force and, therefore, power generation could be raised by introducing NdFeB permanent magnets in the slots of generator. Comparison of the conventional contactless generator and the generator with permanent magnets shows that the latter outperforms the former by such parameters as rotational speed range, efficiency and output, having at the same time smaller weight. The results of practical studies evidence that the inductor generator with a combined excitation system (electromagnetic excitation plus permanent magnets) can be a reliable power source in the independent wind-hydrogen systems.
An Optimized Tooth Zone for the Low-Speed Double-Fed Induction Generator
The authors present the results of tooth zone optimization for a double-fed induction generator able to operate at a low speed. The generator has a large number of pole pairs, all the windings are placed on the stator, with a winding-less toothed rotor. The optimization concerns the geometry of the tooth zone and is achieved by making the pole extension of trapezoidal shape instead of circular, which allows a 4% increase in the generated power.