The corresponding mathematical models have become indispensable tools in the design, analysis and control of complex technical systems. The new mathematical tools are requested continuously for obtaining better agreement regarding the behaviour of models and actual devices. The main reason for the continuous development of existing models is the fact that model-based analytical or numerical analysis can equivalently replace the number of laboratory prototypes and tests, leading to faster prototyping and transfer to production. The corresponding methods for the determination of models' parameters were also developed for new models. Applying some of the new non-linear control approaches for controlling high performance servo drives and complex electromechanical systems considerably increased dynamic performances. The new approach for the analysis of power system dynamics has been introduced by using the theory of end dimensional vector spaces. This approach is indeed revolutionary, because it introduces some doubts about the suitability of existing definitions in electrical power engineering, being appropriate only in the steady state with harmonic excitation. The research work was done in cooperation with foreign research institutions which is confirmed by some common publications. The citation for the results by the International Research Society already confirms the effectiveness of the obtained results.