Browsing by Author "Zeinali, Reza"

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Citation - Scopus: 2
An Approach for Performance Prediction of Saturated Brushed Permanent Magnet\rdirect Current (dc) Motor From Physical Dimensions
(Tubitak Scientific & Technological Research Council Turkey, 2022) Asl, Rasul Tarvirdilu; Zeinali, Reza; Ertan, Hulusi Bulent; Electrical-Electronics Engineering; 06. School Of Engineering; 01. Atılım University
An analytical approach for performance prediction of saturated brushed permanent magnet direct current\r(DC) motors is proposed in this paper. In case of a heavy saturation in the stator back core of electrical machines, some\rflux completes its path through the surrounding air, and the conventional equivalent circuit cannot be used anymore.\rThis issue has not been addressed in the literature. The importance of considering the effect of the flux penetrating\rthe surrounding air is shown in this paper using finite element simulations and experimental results, and an analytical\rapproach is proposed to consider this effect on magnet operating point determination and performance prediction of\rsaturated brushed permanent magnet DC motors. An analytical method is also presented to determine the boundary\rradius of the surrounding air for obtaining accurate results in finite element (FE) solutions and analytical calculations.\rAn analytical approach based on Carter’s coefficient is also proposed to calculate the effective length of the magnet when\rthe length of the magnet and rotor length are not the same. The accuracy of the proposed analytical model is illustrated\rusing finite element simulations and experimental results. With this accuracy, this analytical model is very suitable to\rbe used for reliable and quick mathematical design optimization.
Citation - WoS: 2
Comparison of a Magnetically Geared Pm Wind Generator With Radial Flux Generator
(Ieee, 2018) Zeinali, Reza; Ertan, H. Bulent; Electrical-Electronics Engineering; 06. School Of Engineering; 01. Atılım University
Direct drive wind turbines promise to be more reliable and efficient than commonly used geared wind turbines. This paper presents part of a study aiming to identify whether "Dual Stator Spoke Array Vernier Permanent Magnet" (DSSAVPM) generators present an advantage, regarding size or cost, as compared to the conventional radial flux PM machine for direct drive applications. For this purpose, design of both machines is optimized for the same specifications and using the same design criteria. Optimization results are presented and discussed. It is found that a DSSVPM generator design, with almost the same performance as the RFPM generator, but with 45% of its mass is possible.
Citation - WoS: 1
Fem-Based Design Modifications and Efficiency Improvements of a Brushed Permanent Magnet Dc Motor
(Ieee, 2017) Tarvirdilu-Asl, Rasul; Zeinali, Reza; Ertan, H. Bulent; Electrical-Electronics Engineering; 06. School Of Engineering; 01. Atılım University
This paper describes design modifications of a brushed permanent magnet DC motor. Test motor is modeled using a Finite Element Method (FEM) based software. Model accuracy is investigated by comparing measurement and simulation results. Reducing material consumption in motor fabrication while the motor develops the desired torque at a higher efficiency is aimed in this paper. Modifications are done in three stages and simulations results are also presented. These results are also compared to simulation results of the test machine.
Citation - WoS: 2
Magnetically Geared Direct Drive Wind Generator Thermal Analysis
(Ieee, 2017) Zeinali, Reza; Ertan, H. Bulent; Yamali, Cemil; Tarvirdilu-Asl, Rasul; Electrical-Electronics Engineering; 06. School Of Engineering; 01. Atılım University
This paper considers Dual Stator Spoke Array Vernier Permanent Magnet (DSSA-VPM) generator for the direct drive wind-electric energy conversion. The structure of the generator is described. Although how this design is optimized is not discussed, dimensions of the designed generator are given. In electrical machine design thermal performance is naturally of utmost importance. In this paper thermal performance of the design and how its temperature can be kept within the temperature limit imposed by its insulation class and the permanent magnets used is investigated. It is found that when air flow within the generator is not permitted, at rated load condition the generator temperature reaches very high levels. To lower the operating temperature, ventilation holes are introduced to the end plates of the frame. Also some blades are placed on the rotor to help flow of air over the end windings. A model is introduced to calculate the air speed in the region where air flows. Using the calculated air speed a new heat transfer coefficient is determined for the region where air flows. It is found out that with the mentioned modifications to the structure of the generator the designed generator temperature rise can be kept within the value permitted for its insulation class. Therefore, the power density of the design can be safely compared with the power density of other types of designs for direct drive turbines. It is found that DSSA-VPM generator topology offers a clear advantage over other types of generators considered in the literature.