Pan Seok Shin

An Optimal Design of Large Scale Permanent Magnet Pole Shape Using Adaptive Response Surface Method With Latin Hypercube Sampling Strategy

The latin hypercube sampling (LHS) strategy is applied to the optimization of a magnet pole shape of large scale BLDC motor to minimize the cogging torque with an adaptive response surface method. In the strategy, the qualities of sampling points are evaluated in the viewpoint of uniform space-filling by using Min-distance and Max-distance metrics, and optimum sampling points are obtained in Pareto-optimal sense. An adaptive sampling point insertion is also achieved utilizing design sensitivities computed by using finite element method to get a reasonable response surface with a relatively small number of sampling points. The LHS strategy is incorporated with (1+lambda) evolution strategy, and applied to the permanent magnet pole shape optimization of 6 MW BLDC motor, and the results are compared with those of other algorithms.

Shape Optimal Design of a 9-pole 10-slot PMLSM for Detent Force Reduction Using Adaptive Response Surface Method

The detent force of a permanent magnet linear synchronous motor (PMLSM) consists of cogging and drag forces, and should be minimized for high precision purpose application. This paper suggests a new 9-pole 10-slot structure of a short primary PMLSM to remove the cogging force. Through theoretical and finite element analysis, the proposed structure is proven to remove most of the cogging force. The detent force is minimized by optimizing the length of armature core and shape of the exterior teeth simultaneously by using (1+lambda) evolution strategy coupled with response surface method using multi-quadric radial basis function. Additionally, simulation results for the proposed structures are verified by experimental measurements.

An Application of Latin Hypercube Sampling Strategy for Cogging Torque Reduction of Large-Scale Permanent Magnet Motor

An adaptive response surface method with Latin hypercube sampling strategy is employed to optimize a magnet pole shape of large-scale brushless direct current (BLDC) motor to minimize the cogging torque. The proposed algorithm consists of the multi-objective Pareto optimization and (1+ lambda) evolution strategy to find the global optimal points with relatively fewer sampling data. In the adaptive response surface method (RSM), an adaptive sampling point insertion method is developed utilizing the design sensitivities computed by using finite-element method to get a reasonable response surface with a relatively small number of sampling points. The developed algorithm is applied to the shape optimization of PM poles for 6 MW BLDC motor, and the cogging torque is reduced to 19% of the initial one.

A New Anisotropic Bonded NdFeB Permanent Magnet and Its Application to a Small DC Motor

This paper reports the method of preparing 4-pole-oriented anisotropic bonded NdFeB magnet and presents an application to a small size dc motor. The influence on the magnet performance in terms of alignment magnetic field intensity, powder filling density, and the temperature of compression mold tools are investigated. The design and optimization of the magnet and motor were done with the aid of electromagnetic field analysis based on the finite element method. Experimental results with a designed dc motor adopting the developed anisotropic bonded NdFeB magnet show 50% reduction of weight and volume.

A back EMF optimization of double layered large scale BLDC MOTOR by using hybrid optimization method

This paper presents an optimization method of the back EMF for the double layered (double air gap) large-scale BLDC motor by using a Latin-hypercube sampling strategy. In order to drive the large-scale BLDC motors in parallel and multiphases, the back EMF of inner stator is equal to the back EMF of the outer. A new configuration of the double layered BLDC motor is also proposed for the compactness and high efficiency of the system. By the optimization, it is concluded that the skew angle and the thickness difference between the outer and inner magnets have important roles in synchronization and same magnitude of the back EMF, respectively.

Finite Element Implementation Of A Generalized Chua-Type Vector Hysteresis model and application to iron loss analysis of three-phase transformer

This paper presents a generalized Chua-type vector hysteresis model, and a precise magnetic field analysis method is developed by combining the proposed model with the finite element method. The proposed model takes account of all the significant harmonic components of the measured H-waveforms. The validity of the proposed model is investigated through an application to a three-phase transformer model and comparison to experimental measurement.

Application of Polar Anisotropic NdFeB Ring-Type Permanent Magnet to Brushless DC Motor

A four-pole polar anisotropic sintered NdFeB permanent magnet (PM) with high surface magnetic flux density is developed using a dry pressing process with pulse magnetizing fields. The effects of powder-filling density, magnetic field intensity, distribution in the cavity, and premagnetization of the powder on the magnet performance are investigated. Through an application of the developed PM to a brushless DC motor, it is shown that the premagnetization of the powder is very effective for increasing the surface magnetic flux density. Experimental results with a brushless DC motor adopting the developed PM shows that the surface magnetic flux density is increased up to 0.63 T, and the back emf at 1000 rpm measured 2.7 V, which is 41% higher than the conventional segment type PM

Accuracy Improved Dynamic E&S Vector Hysteresis Model and its Application to Analysis of Iron Loss Distribution in a Three-Phase Induction Motor

This paper presents an improved dynamic E&S vector hysteresis model to increase modeling accuracy under non-elliptic B-waveforms and describes its implementation to the finite element method (FEM). Since the dynamic E&S model is expressed via magnetic reluctivity and hysteresis coefficients modeling the vector hysteresis property of electrical steel sheet, its modeling accuracy strongly depends on the method of determination of the coefficients. The proposed model increases the modeling accuracy by improving the coefficient calculation algorithm especially under non-elliptic distorted magnetic flux density conditions. The proposed model is incorporated with FEM and applied to iron loss analysis of a three-phase induction motor.

A Free Vibration Analysis of Helical Windings of Power Transformer by Pseudospectral Method

This paper proposes a new use of the pseudospectral method to the eigenvalue analysis of the power transformer winding. The analysis method is based on the Chebyshev polynomials and collocated at the Gauss-Labatto collocation points. To verify the method, a helical-type winding of a power transformer is analyzed and numerical examples are provided for various boundary conditions. The computed results are in good agreement with finite-element method solutions. It shows that the method is straightforward and it has novel advantages in its conceptual simplicity

An optimum design of rotor slot shape of induction motor for electric vehicles using numerical techniques

A rotor slot shape of induction motor for electric vehicle is optimized by FEM with the numerical techniques. To optimize the rotor slot shape, two objective function and 3 variables are defined, and the optimization algorithm is developed. To verify the program, 4 poles 44 kW induction motor is modeled, simulated and analyzed by the program. The optimized rotor slot shape result makes reasonably good improvement to increase torque and efficiency of the motor performance.