Modeling and Optimization of Brushless Electrical Machines for Challenging Performance Requirements

It is not possible to imagine our daily life without electrical drives even though one is often oblivious of their presence. For instance, they are used as generators for producing electrical energy, as work machines in industry, in households and automobiles. Due to the ever increasing number of operated electrical drives worldwide and the associated dramatical increase of electrical energy consumption efficiency improvements for electrical machines are superimportant. Thus, improving the efficiency factor of electrical machines takes top priority and constitutes the chief subject of this thesis. A Fourier series based modeling of the key parameters of electrical drives is developed which rests upon fundamental reflections of the electromechanical energy conversion. The obtained model is improved by the comprehensive generalized analysis of frequency components of the torque and the linked fluxes and thus provides clearer understanding of the frequency-dependent characteristics of electrical machines. Furthermore, it allows for the design of new methods to significantly enhance the performance of electrical drives. In the course of this thesis a novel technique for the design of electrical machines was developed that allows for the simultaneous improvement of the power density and the efficiency on the one hand and the true running accuracy on the other hand.