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Title: Cogging Torque Minimization in Transverse Flux Machines

Abstract

This paper presents the design considerations in cogging torque minimization in two types of transverse flux machines. The machines have a double stator-single rotor configuration with flux concentrating ferrite magnets. One of the machines has pole windings across each leg of an E-Core stator. Another machine has quasi-U-shaped stator cores and a ring winding. The flux in the stator back iron is transverse in both machines. Different methods of cogging torque minimization are investigated. Key methods of cogging torque minimization are identified and used as design variables for optimization using a design of experiments (DOE) based on the Taguchi method. A three-level DOE is performed to reach an optimum solution with minimum simulations. Finite element analysis is used to study the different effects. Two prototypes are being fabricated for experimental verification.

Authors:
; ; ; ;
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Wind and Water Technologies Office (EE-4W)
OSTI Identifier:
1351844
Report Number(s):
NREL/CP-5D00-66390
DOE Contract Number:
AC36-08GO28308
Resource Type:
Conference
Resource Relation:
Conference: Presented at the 2016 IEEE Energy Conversion Congress and Exposition (ECCE), 18-22 September 2016, Milwaukee, Wisconsin
Country of Publication:
United States
Language:
English
Subject:
24 POWER TRANSMISSION AND DISTRIBUTION; transverse flux machine; permanent magnet machine; cogging torque reduction; design of experiment; optimization

Citation Formats

Husain, Tausif, Hasan, Iftekhar, Sozer, Yilmaz, Husain, Iqbal, and Muljadi, Eduard. Cogging Torque Minimization in Transverse Flux Machines. United States: N. p., 2017. Web. doi:10.1109/ECCE.2016.7854923.
Husain, Tausif, Hasan, Iftekhar, Sozer, Yilmaz, Husain, Iqbal, & Muljadi, Eduard. Cogging Torque Minimization in Transverse Flux Machines. United States. doi:10.1109/ECCE.2016.7854923.
Husain, Tausif, Hasan, Iftekhar, Sozer, Yilmaz, Husain, Iqbal, and Muljadi, Eduard. Thu . "Cogging Torque Minimization in Transverse Flux Machines". United States. doi:10.1109/ECCE.2016.7854923.
@article{osti_1351844,
title = {Cogging Torque Minimization in Transverse Flux Machines},
author = {Husain, Tausif and Hasan, Iftekhar and Sozer, Yilmaz and Husain, Iqbal and Muljadi, Eduard},
abstractNote = {This paper presents the design considerations in cogging torque minimization in two types of transverse flux machines. The machines have a double stator-single rotor configuration with flux concentrating ferrite magnets. One of the machines has pole windings across each leg of an E-Core stator. Another machine has quasi-U-shaped stator cores and a ring winding. The flux in the stator back iron is transverse in both machines. Different methods of cogging torque minimization are investigated. Key methods of cogging torque minimization are identified and used as design variables for optimization using a design of experiments (DOE) based on the Taguchi method. A three-level DOE is performed to reach an optimum solution with minimum simulations. Finite element analysis is used to study the different effects. Two prototypes are being fabricated for experimental verification.},
doi = {10.1109/ECCE.2016.7854923},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Feb 16 00:00:00 EST 2017},
month = {Thu Feb 16 00:00:00 EST 2017}
}

Conference:
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  • This paper presents the design considerations in cogging torque minimization in two types of transverse flux machines. The machines have a double stator-single rotor configuration with flux concentrating ferrite magnets. One of the machines has pole windings across each leg of an E-Core stator. Another machine has quasi-U-shaped stator cores and a ring winding. The flux in the stator back iron is transverse in both machines. Different methods of cogging torque minimization are investigated. Key methods of cogging torque minimization are identified and used as design variables for optimization using a design of experiments (DOE) based on the Taguchi method.more » A three-level DOE is performed to reach an optimum solution with minimum simulations. Finite element analysis is used to study the different effects. Two prototypes are being fabricated for experimental verification.« less
  • In this paper, we investigate three design options to minimize cogging torque: uniformity of air gap, pole width, and skewing. Although the design improvement is intended for small wind turbines, it is also applicable to larger wind turbines.
  • This research examines the vibration and thermal characteristics of double-sided flux concentrating Transverse Flux Machines (TFM), designed for direct drive application. Two TFM prototypes with different stator cores, one with Quasi U-Core and the other with E-Core, has been used for the study. 3D Finite Element Analysis (FEA) has been carried out to determine the no-load and with load performance of the TFMs along with their fluctuating axial electromagnetic force densities acting on the stator teeth. The deformation response of the stator cores was observed in the static structural analysis. Thermal analysis for the TFM was performed through FEA basedmore » on copper and iron losses in the machine to examine the temperature rise in different parts of the machine structure. Acceleration and noise measurements were experimentally obtained to characterize the vibrational performance of the prototypes.« less
  • The use of direct drive machines in renewable and industrial applications are increasing at a rapid rate. Transverse flux machines (TFM) are ideally suited for direct drive applications due to their high torque density. In this paper, a comprehensive review of the permanent magnet (PM) TFMs for direct drive applications is presented. The paper introduces TFMs and their operating principle and then reviews the different type of TFMs proposed in the literature. The TFMs are categorized according to the number of stator sides, types of stator cores and magnet arrangement in the rotor. The review covers different design topologies, materialsmore » used for manufacturing, structural and thermal analysis, modeling and design optimization and cogging torque minimization in TFMs. The paper also reviews various applications and comparisons for TFMs that have been presented in the literature.« less
  • The lack of the filtering effect due to gear reduction in a direct-drive system necessitates the consideration of the full dynamics of the system for high performance control. This makes torque ripple a significant problem and its elimination is required for improved performance. In the study, adaptive linearizing control is applied for the solution of the problem in a single-link manipulator driven by a permanent magnet synchronous motor. Two parameterization methods, which were analyzed in terms of stability and robustness in a previous study, are implemented for the linearization of the direct-drive system. Speed and position control experiments are performedmore » for both parameterizing approaches, also taking load torque variations into account and an improved performance is obtained in terms of torque ripple reduction and tracking error. Especially with the guaranteed persistency of excitation of the new parameterization approach, a significant reduction of torque ripple amplitude is achieved in addition to parameter and error convergence under load variations for both speed and position control. The experiments are performed through a DSP32 driven motion controller.« less