Yong-Min You

Rotor Shape Optimization of Interior Permanent Magnet BLDC Motor According to Magnetization Direction

This paper proposes the optimization of an anisotropic ferrite magnet shape and magnetization direction to maximize back-EMF of IPM BLDC motor. Firstly, four different models of general magnet shapes are selected, and then FEM analysis is carried out with four different magnetization directions for each of four models. The best magnet shape and magnetization direction from each model are selected as an initial model for optimization. Secondly, based on the initial model, optimization design for maximum back-EMF and minimum cogging torque and THD is performed. Finally, validity and superiority of the optimization design are confirmed by manufacturing the prototype motor and performing the experiment.

Optimal Design of a Grid-Connected-to-Rotor Type Doubly Fed Induction Generator for Wind Turbine Systems

This paper performs a shape optimization of a grid-connected-to-the-rotor type doubly fed induction generator (DFIG) in which the rotor winding is connected to the grid instead of the stator winding. To analyze the characteristics of a DFIG accurately, a time step 2D-FEA is carried out, which is coupled with Simplorer. To maximize the torque per weight as well as to maintain the efficiency, the Kriging model based on latin hypercube sampling and genetic algorithm are utilized. As an optimal design result, the torque per weight on the optimal model has been increased. Finally, the analysis and the optimal design results are confirmed by the experimental results.

Optimal Design of a Distributed Winding Type Axial Flux Permanent Magnet Synchronous Generator

This paper presents a distributed winding type axial flux permanent magnet synchronous generator (AFPMSG) with reduced the total harmonic distortion (THD), suitable for wind turbine generation systems. Although the THD of the proposed distributed winding type is more reduced than the concentrated winding type, the unbalance of the phase back EMF occurs. To improve the unbalance of the phase back EMF and the output power of the distributed winding type AFPMSG, the Kriging based on the latin hypercube sampling (LHS) is utilized. Finally, these optimization results are confirmed by experimental results. As a result, the unbalance of the phase back EMF and the output power of the distributed winding type AFPMSG were improved while maintaining the total harmonic distortion (THD) and the average phase back EMF.

Design and Analysis of a Novel Grid-Connected to Rotor Type Doubly Fed Induction Machine

This paper proposes a novel grid-connected to rotor type doubly fed induction machine (DFIM) in which the rotor winding is connected to the grid instead of the stator winding. The size and weight of the stator can be reduced on the proposed grid-connected to rotor type DFIM, because the proposed type can use the rotor core more efficiently compared to a conventional grid-connected to stator type DFIM. In order to verify the size and weight reduction of the proposed type, the loading distribution method (LDM) is utilized. As a design result, the outer diameter and weight of the stator on the proposed type have been decreased. Equivalent circuit analysis and finite element analysis (FEA) were performed to verify the design results and to analyze the characteristics of the novel DFIM. Finally, these analysis results are confirmed by experimental results.

Optimal Design to Increase Thrust Force in Electro-Magnetic Linear Actuator for Fatigue and Durability Test Machine

This paper introduces the Halbach array and an optimal design process to effectively increase thrust force and decrease the yoke volume in electro-magnetic linear actuator for fatigue and durability test machine. The finite element method is used for dynamic response analysis of the thrust, velocity and displacement. In the optimal design process, sampling points are chosen by Latin hypercube sampling and from the results, an approximation modeling is made by Radial basis function and then the optimization results are obtained by a Genetic algorithm. The simulation results are verified by experimental results. Using the optimal design process enables the optimized electro-magnetic linear actuator to effectively increase the thrust force considering the weight of linear actuator.

Optimal design of distributed winding axial flux permanent magnet synchronous generator for wind turbine systems

In order to reduce harmonic distortion, this paper presents a distributed winding type axial flux permanent magnet synchronous generator (AFPMSG), suitable for wind turbine generation systems. The characteristic analysis is performed with the aid of a 3D finite element method (FEM) and these analysis results are confirmed by the experimental results. To improve the output power and unbalance of the phase back EMF, the optimal design process by using Kriging combined with latin hypercube sampling (LHS) and genetic algorithm (GA) was utilized. As a result, the output power and unbalance of the phase back EMF of the distributed winding type AFPMSG were improved efficiently while maintaining the total harmonic distortion (THD) and the average of the phase back EMF.

A rotor design of a BLDC motor used for reciprocating compressor considering demagnetization

This paper presents the design of a reliable rotor shape of a BLDC motor used for reciprocating compressor considering demagnetization. Three types of rotor shape are proposed for BLDC motor and a proper rotor shape is selected by characteristic analysis using the 2D finite element method ( FEM). To verify the accuracy of the analysis results, a prototype was built and tested. In order to design a reliable rotor shape ag ainst the demagnetization of the ferrite magnet, the demagnetization analysis is performed according to variation of design variables of the ferrite magnet using the 2D FEM. As a result, the BLDC motor with the developed rotor shape showed good performance to resist partial demagnetization.

Digital Implementation of PWM Techniques for Two-phase Eight-switch Inverter fed Brushless DC Motor Drives

This paper reports an investigation of pulse width modulation (PWM) techniques for two-phase brushless DC (BLDC) motors fed by a two-phase eight-switch inverter in a fan application. The three-phase BLDC motor is widely applied in industry; however, a lower-cost two-phase BLDC motor and drive circuit has been greatly in demand in recent years. In this paper, we introduce a mathematical model of the two-phase BLDC motor with sinusoidal back electromotive forces (EMFs) based on traditional three-phase BLDC motors. To simplify the drive algorithm and speed up its application, we analyze the principle of block commutation for a two-phase BLDC motor drive in the 180-electrical-degree conduction mode, and we further propose five PWM schemes to improve the commutation performance of the two-phase BLDC drive. The effectiveness of the proposed PWM methods is verified through experiments.

Design and comparative analysis of single and multi-stack axial flux permanent magnet synchronous generator

This paper attempts to design a direct driven axial flux permanent magnet synchronous generator (AFPMSG) with better accuracy considering magnetic flux leakages and fringing effect, using D 2 L method. Design results of conventional and improved design processes are analyzed and compared using 3D finite element method (FEM). Single and multi-stack AFPMSG topologies are designed by using an improved design process. FEM structural analysis is utilized to improve power to weight ratio of three-stack AFPMSG. Finally characteristics of both single and three-stack AFPMSG topologies are analyzed and compared using 3D FEM analysis.

A novel grid-connected to rotor type doubly fed induction generator for wind turbine systems

This paper proposes a grid-connected to rotor type doubly fed induction generator (DFIG) in which the rotor winding is connected to the grid instead of the stator winding. The stator size and weight of the proposed grid-connected to rotor type DFIG can be reduced because the proposed type can use rotor core more efficiently compared to the stator type DFIG. In order to verify the size and weight reduction of the proposed type, the loading distribution method (LDM) is utilized. As a design result, the stator outer diameter and weight of the proposed type were decreased. The equivalent circuit analysis and FEM analysis also performed to verify the design results and to analyze characteristics of the novel DFIG.