The research paper presents the results of the dynamic analysis of an existing bar dome subjected to wind loads. The calculation model of the structure was constructed using the finite element method. The dome was subjected to the standard wind pressure, assuming that it is operates in a harmonic manner. The numerical analyses were performed with the application of Autodesk Robot and MES3D. The analysis focused on the impact of selected factors such as the frequency of forcing, wind gustiness coefficient and structural damping on the behaviour of structures.

The discrete Fourier transform (DFT) is the main method of electrical harmonic analysis since it’s easily realized in an embedded system. But there were some difficulties in performing synchronized sampling. The spectral leakage caused by asynchronous sampling affects the accuracy of harmonics analysis. Using window functions and interpolation algorithms can improve the accuracy of harmonics analysis. An approach for electrical harmonic analysis based on the interpolation DFT was proposed. A window function reduces DFT leakage and the interpolation algorithm modifies the calculation results of frequency, amplitude and the initial phase angle. The simulation results indicate that, by using the interpolation DFT electrical harmonic analysis method based on the Hanning window or the Blackman window, the error of calculating amplitudes and frequencies is not greater than 0.5%.

The quality of the supplied power by electricity utilities is regulated and of concern to the end user. Power quality disturbances include interruptions, sags, swells, transients and harmonic distortion. The instruments used to measure these disturbances have to satisfy minimum requirements set by international standards. In this paper, an analysis of multi-harmonic least-squares fitting algorithms applied to total harmonic distortion (THD) estimation is presented. The results from the different least-squares algorithms are compared with the results from the discrete Fourier transform (DFT) algorithm. The algorithms are assessed in the different testing states required by the standards.

This paper presents a new modification of the least-squares Prony’s method with reduced sampling, which allows for a significant reduction in the number of the analysed signal samples collected per unit time. The specific combination of non-uniform sampling with Prony’s method enables sampling of the analysed signals at virtually any average frequency, regardless of the Nyquist frequency, maintaining high accuracy in parameter estimation of sinusoidal signal components. This property allows using the method in measuring devices, such as for electric power quality testing equipped with low power signal processors, which in turn contributes to reducing complexity of these devices. This paper presents research on a method for selecting a sampling frequency and an analysis window length for the presented method, which provide maximum estimation accuracy for Prony’s model component parameters. This paper presents simulation tests performed in terms of the proposed method application for analysis of harmonics and interharmonics in electric power signals. Furthermore, the paper provides sensitivity analysis of the method, in terms of common interferences occurring in the actual measurement systems.

Fractional-slot concentrated-winding permanent magnet synchronous machines (FSCW-PMSMs) have a good prospect of application in the drive system of electric and hybrid electric vehicles. However, the armature magnetomotive force (MMF) of FSCWPMSM contains a large number of space harmonics, which induce large magnet eddycurrent loss (ECL). To solve this problem, a dual three-phase 10-pole and 24-slot winding layout is proposed.MMFharmonic analysis shows that the 1st, 7th and 17th space-harmonic winding factors of the proposed winding can be reduced by 100%, 87% and 87% respectively, compared with a dual three-phase 10-pole and 12-slot winding. Electromagnetic performances of the proposed machine under rated sinusoidal current supply and space vector pulse-width-modulated (SVPWM) voltage supply are investigated based on 2D finite-element analysis. It is shown that the proposed machine can meet the requirement of torque and efficiency in the full speed range. Especially, magnet ECL can be reduced greatly due to the reduction of the 7th and 17th space harmonics.