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A hybrid analytical and lumped-parameter thermal model is proposed in this paper to estimate the transient and steady-state two- and three-dimensional (2/3-D) spatial magnet temperature distributions for an interior permanent magnet synchronous machine (IPMSM). On the basis of a lumped-parameter thermal model (LPTM), the magnet analytical thermal models (ATMs) are synergized to establish the hybrid thermal model. By utilizing the transient or steady-state boundary conditions calculated by the LPTM, the ATMs are obtained by solving the heat conduction equations to estimate the spatial magnet temperature distributions in the 2-D horizontal-vertical and axial-vertical planes, which can also be extended to the 3-D temperature distribution by utilizing the multi-slice method. Meanwhile, the non-uniform magnet eddy current loss is also considered. Finally, both electromagnetic-thermal coupled finite element analysis method and experiments are used for verification based on a totally enclosed IPMSM. [ABSTRACT FROM AUTHOR]

In this article, a simplified three-dimensional (3-D) hybrid analytical thermal model for surface-mounted permanent magnet (PM) synchronous machines is proposed and applied to investigate the influence of PM segmenting strategies on the spatial PM temperature distributions and hotspots. The developed 3-D hybrid thermal model synergies the lumped-parameter thermal model and analytical method and is able to estimate 3-D spatial temperature distributions and hotspots for both unsegmented and segmented surface-mounted PMs accounting for the uneven PM eddy current loss distributions. Meanwhile, by utilizing the proposed matrix-based post-processing methods, the developed hybrid analytical thermal model has a simple mathematical expression but persists in high estimation accuracy. Finally, the proposed hybrid analytical modelling method is validated by 3-D electromagnetic-thermal coupled FEA and experiments. [ABSTRACT FROM AUTHOR]

The lumped-parameter thermal network (LPTN) has been widely used in the thermal analysis for electrical machines. Nevertheless, since the thermal resistances are defined based on the one-dimensional (1-D) heat transfer equation, it will cause the misestimation of the average temperatures when the thermal model extends to two dimensions or three dimensions. In this article, a hybrid thermal model utilizing the synergies of LPTN and 2-D analytical thermal models is developed to address this issue and to predict accurate critical temperatures, especially the average and maximum temperatures of the active and end windings. The 2-D analytical thermal models are obtained by solving the Poisson's equations with the Dirichlet boundary conditions extracted from the LPTN. The derived analytical solutions are expressed as the Fourier series, which can be further simplified by utilizing the first term only to represent average and maximum temperatures with sufficient accuracy and short computation time. The hybrid thermal model is applied to a totally enclosed forced convection permanent magnet synchronous machine and validated by numerical techniques and experiments. [ABSTRACT FROM AUTHOR]

In this paper, the iron loss models for electrical machines are first reviewed. One of the most accurate iron loss models, when the temperature is constant, is identified. An improved temperature-dependent iron loss model is also introduced. By applying the improved iron loss model to the electrical machine thermal analysis, the thermal and loss analyses can be fully coupled. Based on this, an improved thermal-loss coupling analysis method for electrical machine is developed in this paper. The electrical machine iron loss tests are carried out. The analysis and measurement results are then compared in order to validate the improved thermal-loss coupling analysis method. The comparison results indicate that the temperature prediction accuracy can be significantly improved by using the improved thermal-loss coupling analysis method. [ABSTRACT FROM AUTHOR]

In this paper, the different temperature dependencies of hysteresis and eddy current losses of non-oriented Si-steel laminations are investigated. The measured iron loss results show that both the hysteresis and eddy current losses vary linearly with temperature between 40 °C to 100 °C, a typical temperature range of electrical machines. Varying rates of hysteresis and eddy current losses with the temperature are different and fluctuate with flux density and frequency. Based on this, an improved iron loss model which can consider temperature dependencies of hysteresis and eddy current losses separately is developed. Based on the improved iron loss model, the temperature influence on the iron loss can be fully considered by measuring iron losses at only two different temperatures. The investigation is experimentally validated by both the tests based on a ring specimen and an electrical machine. [ABSTRACT FROM PUBLISHER]

In this paper, the temperature dependencies of iron loss under different flux densities, frequencies, and dc bias flux densities are systematically investigated. The temperature dependence of the hysteresis loss varies significantly with the dc bias flux density while that of the eddy current loss is independent of the dc bias flux density. Based on these different characteristics of the hysteresis and the eddy current iron losses, an improved iron loss model is developed. The temperature dependence of iron loss under dc bias condition can be considered by utilizing the improved iron loss model. The developed iron loss model is validated by both tests on laminations and an electrical machine. [ABSTRACT FROM AUTHOR]

In this paper, the investigation is focused on the iron loss prediction for electrical machines fed by low switching frequency inverter. An improved iron loss model is developed after reviewing various existing iron loss models considering pulse-width modulation (PWM) influence. In order to validate the improved iron loss model, iron loss tests are carried out on an electrical machine. The predicted iron loss results match well with the measured results, which shows that the improved iron loss model is able to predict iron loss in electrical machine fed by an inverter. The comparison between the predicted iron losses with and without considering the PWM influence shows that the iron loss can be significantly increased due to the influence of PWM, especially when the switching frequency is low. [ABSTRACT FROM AUTHOR]

In this study, the temperature influence on iron loss of non‐oriented steel laminations is investigated. The iron loss variation under different flux densities, frequencies and temperatures is systematically measured and analysed by testing two typical non‐oriented steel laminations, V300‐35 A and V470‐50 A. The iron loss variation with temperature is almost linear in the typical operating temperature range of electrical machines. Furthermore, the varying rate of iron loss with temperature varies with flux density and frequency. A coefficient which can fully consider the temperature influence is introduced to the existing iron loss model to improve the iron loss prediction accuracy. The predicted and measured results show that the temperature influence on the iron loss can be effectively considered by utilising the improved model, i.e. the prediction accuracy of the improved iron loss model remains constant, even when the temperature varies significantly. A potential simplification of this improved model is also discussed in this study. [ABSTRACT FROM AUTHOR]