Establishing the Relative Merits of Interior and Spoke-Type Permanent-Magnet Machines With Ferrite or <roman>NdFeB</roman> Through Systematic Design Optimization

Abstract

In this paper, a multiobjective design optimization method combining design-of-experiments techniques and differential-evolution algorithms is presented. The method was implemented and utilized in order to provide practical engineering insights for the optimal design of interior and spoketype permanent-magnet machines. Two combinations with 12 slots and 8 poles and 12 slots and 10 poles, respectively, have been studied in conjunction with rare-earth neodymium-iron-boron (NdFeB) and ferrites. As part of the optimization process, a computationally efficient finite-element electromagnetic analysis was employed for estimating the performance of thousands of candidate designs. Three optimization objectives were concurrently considered for minimum total material cost, power losses, and torque ripple, respectively. Independent variables were considered for both the stator and rotor geometries. A discussion based on a systematic comparison is included, showing, among other things and despite common misconception, that comparable cost versus loss Paretos can be achieved with any of the rotor topologies studied. VERSION; this is the author's final, peer-reviewed manuscript. The published version may be accessed by following the link in the citation at the bottom of the page. NOT THE PUBLISHED

Computationally Efficient Strand Eddy Current Loss Calculation in Electric Machines

“…The CE-FEA method was developed and compared with the detailed time-stepping transient FEA (TS-FEA) in [30]. Subsequently, it was used in large-scale design optimizations of PM machines in [23] and [26]- [28], and also was utilized in calculation of eddy current PM losses in concentrated winding PM machines in [31].…”

“…However, the presented method accounts for the effects of motion, saturation, and interaction between stator and rotor magnetomotive forces, and provides a reasonable compromise between computational time and accuracy, which makes it suitable for application in the large-scale design optimization of PM machines in the initial stages of the design. Examples of such large-scale design optimization algorithms in which thousands of design candidates with several control parameters are evaluated are reported in [23]- [24][25] [26][27] [28].…”

Large-Scale Design Optimization of PM Machines Over a Target Operating Cycle

“…The CE-FEA concept has also been utilized to calculate the rotor magnet losses of concentrated-winding PM synchronous machines [4]. The design optimization method based on CE-FEA and DE has since been used to identify the existing trade-offs in multiobjective design of PM machines [5], or to establish the relative merits of counterpart PM motor topologies [6].…”

“…Depending on the particular application, the CE-FEA based design optimization techniques aim at realizing a set of objectives under certain performance constraints described/embedded in the optimization fitness function [2][3][4][5][6][7]. In line with the common practice, the CE-FEA based methods evaluate the associated fitness function at the rated load point, i.e.…”

Optimal Design of IPM Motors With Different Cooling Systems and Winding Configurations

“…Accordingly, design recommendations for mitigation of torque ripples, minimization of power losses, and reducing dependency on rare-earth PMs, have been often reported in the literature for naturally cooled (NC) machines. 9,10,11,16,17 Nevertheless, increasing the stator winding current density or the machine's ampere loading elevates the flux level and, hence, the saturation level throughout the machine's magnetic circuit. This not only affects the machine performance, but also alters the correlation between them and the geometric design parameters associated with the machine cross-section.…”