فهرست مطالب seyed ehsan abdollahi

Self- and mutual inductance are key parameters of the WPT system, and to optimize such systems or estimate its performance parameters such as received power, efficiency, and gain, the designer must calculate them correctly. Analytical calculation of self- and mutual inductance compared to the finite element simulation method speeds up the design process and reduces costs. The polarized DD pads are selected in this paper due to the simplicity of structure, high efficiency, and low sensitivity to misalignment conditions. DD pads are very popular in electric vehicle charging applications (dynamic and static). In this paper, analytical calculations of self and mutual inductance using Biot-Savart law for DD pads are presented. In some cases, the use of ferrite cores to improve the inductance and coupling coefficient of these pads is necessary. Therefore, the effect of ferrite cores and optimization in terms of number, length, and distance between cores in finite element simulation has been investigated. In some cases, it is necessary to use ferrite cores, so the effect of ferrite cores and optimization in this pad has been investigated. The results of analytical calculations of mutual inductance in different distances between pads have been investigated and the results of calculations verified with experimental and FEM simulation. The values calculated by the practical method and simulation with good accuracy verify the analytical model.

Doubly Fed Induction Generator (DFIG) is one of the important generators that is used in the wind turbine structures. In the past few years, DFIG-based wind turbine systems that have been installed in the onshore and offshore wind farms are greater in number, than any other generator. Since the number of references that present the DFIG designing field are limited and equations and the design process are incompletely reviewed, in this paper the complete design process of a 250kW DFIG is presented. First, the optimal design equations of DFIGs are reviewed and then a model for the study of generator operation is presented. The detailed design of the DFIG is done next, and finally the Finite Element Analysis (FEA) is used to verify the design. The results show the effectiveness of the presented design process for the DFIG.

Flux switching (FS) machines have recently received much attention because of their high torque density and their simple rotor structure. In these machines, the armature coil and excitation system are both mounted on the stator structure, and there is no coil, magnet or cage on the rotor. One of the drawbacks of the FS machines is the employment of large amounts of expensive rare earth magnets in their stator structure. Although ferrite permanent magnets can be used instead of rare earth magnets with about one tenth of the price, but the machine torque density is reduced. To solve this problem double stator structures are suggested. In machines with this structure, as in the conventional FS machines, the number of rotor teeth has a significant effect on machine’s performance. Therefore, in this paper, the effect of rotor topology on the performance of a double stator ferrite magnet FS machine is investigated using finite element modeling and simulation under nominal operating conditions. Finally, to evaluate the accuracy of simulation results, a prototype of the best structure with maximum torque is manufactured and tested. The test results confirm the correctness of the simulation results with considerable accuracy.

The rotor structure of a synchronous reluctance machine (SynRM) engages some design complexities. These complexities have made it impossible to employ a generalized design method valid for all machine topologies with various number of rotor and stator slots till now. However, using trial and error and optimization algorithms such as genetic algorithms, etc., an optimal design is obtained which is both time consuming and complicated. Indeed, high amount of ripple in the developed torque is a serious problem of SynRMs, which could be reduced by employing an effective design method. This paper presents a new SynRM rotor analytical design method with the aim of reducing torque ripple while maintaining average torque. To this end, the proposed method is applied to a SynRM with 24 stator slots and 2, 3, and 4 rotor flux barriers. In order to evaluate the proposed method’s effectiveness, three designed SynRMs’ electromagnetic performances are simulated using finite elements method (FEM). It has been shown that the design parameters resulted by the proposed analytical method is close to the optimal state obtained by preceding time-consuming complicated methods.

Linear induction motors (LIMs) are widely employed in rail transportation systems due to their robust, simple and low cost structure. Several methods have evaluated various topologies'' performances in the literature. These methods are more and less effective in the intended structures. In this paper, a new two-dimensional analytical method is presented in order to predict developed thrust force of a single-sided linear induction motor with a solid iron secondary. The skin and saturation effects of the induced eddy currents in the solid iron of the secondary are considered in the proposed method. The analytical results are then compared with the 2D finite element simulation and the experimental ones of the research work of Gieras et al. .Results confirm the accuracy of the proposed analytical and finite element methods for the analysis and design of linear induction motors with solid iron secondary.