This paper presents the theory about generating the braking curve and the analysis of the influence of the braking controller parameters on the generation of the braking curve of the train. In this paper, computed examples of braking quality developed using generic quality factor are shown, and on the basis of the calculations, weight components of the factor and an additional criterion for assessing the quality of braking were proposed. It has been demonstrated that the developed algorithms can be used to verify the effectiveness of the braking controller and the adjustment of the terms, and the change of these algorithms affects the shape of the generated braking curve of the train. It has been shown that the analysis of a failure of the propulsion car revealed the existence of a safe braking area. The performed statistical analysis confirmed the normal distribution of the scatter of braking results, for which the regression model fitted.

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Summary. This paper presents the possibility of using a fuzzy controller to correct metrological properties of an electric traction energy meter. So far, no algorithms based on fuzzy logic to determine the desired conversion value of the current channel of the electricity meter have been applied. Currently, for the mentioned channel, conventional methods of gain determination are used, based on a sequential algorithm that controls operation of the programmable gain amplifier. The proposed corrector is designed for smart and continuous modification of the conversion factor of the low-voltage input part of the current channel in the electric energy meter. The authors have performed an accurate analysis of the current function in the main circuit of an electric locomotive by creating a model of a traction inverter subject to asynchronous motor load. An essential concept is this paper is to present the possibility of having a multi-input fuzzy controller split into two-input controllers connected in parallel and cascade. By performing a computer simulation of systems used for correcting metrological properties of electric traction energy meters, it has been proven that the applied fuzzy systems, based on an expert's knowledge of digitally controlled PGA (Programmable Gain Amplifier) type operational amplifiers, are advantageous.

PurposeThe calculation of the power loss in the core of the electrical machines is a special problem. In some areas of the electrical machine core the magnetic fields are neither unidirectional nor sinusoidal. This paper seeks to discuss the rotational power loss calculation methodology.Design/methodology/approachThe proposed methodology is based on the calculation of the field quantities Bx and By. In this methodology the rotational power losses are calculated employing the empirical approach directly from these quantities. Moreover, the computational model is the most important element of the proposed methodology because it utilises the FEM to the calculations of the hodographs of the flux density vector in each mesh element.FindingsThe paper formulates the dependence of the rotational power losses from the B vector hodograph shape.Research limitations/implicationsExperimental verification will still be needed as to the accuracy of the model and the applicability to the various magnetic materials.Practical implicationsThe paper provides an easy mathematical method to the iron loss calculation, under the rotational magnetisation, the excess loss included.Originality/valueThe analytical model, as presented here, is applicable to the iron loss calculation under the rotational magnetisation in devices that have complicated geometrical shapes.