Ju-Hee Cho

Electromagnetic Field and Thermal Linked Analysis of Interior Permanent-Magnet Synchronous Motor for Agricultural Electric Vehicle

This paper presents a 3D numerical analysis of the thermal transient behavior of the air-cooled interior permanent-magnet synchronous motor (IPMSM) for agricultural electric vehicle (AEV) using finite-element method (FEM). The air-cooled IPMSM is investigated the temperature variation for the insulation of winding coil and demagnetization of permanent-magnet during the rated operation. Therefore, the prediction of a motor temperature is necessary at the motor design stage. This paper shows a good agreement both the numerical calculation and experimental results. The proposed method, electromagnetic field and thermal linked analysis, is able to predict the temperature distribution of IPMSM with the rated 7.5 kW continuous power.

A Novel Cogging Torque Reduction Method for Single-Phase Brushless DC Motor

Single-phase, brushless DC (BLDC) motors have unequal air-gaps to eliminate the dead-point where the developed torque is zero. Unfortunately, these unequal air-gaps can deteriorate the motor characteristics in the cogging torque. This paper proposes a novel design for a single-phase BLDC motor with an asymmetric notch to solve this problem. In the design method, the asymmetric notches were placed on the stator pole face, which affects the change in permanent magnet shape or the residual flux density of the permanent magnet. Parametric analysis was performed to determine the optimal size and position of the asymmetric notch to reduce the cogging torque. Finite element analysis (FEA) was used to calculate the cogging torque. A more than 28% lower cogging torque compared to the initial model with no notch was achieved.

Thermal Analysis of Interior Permanent-Magnet Synchronous Motor by Electromagnetic Field-Thermal Linked Analysis

This paper reports an investigation of pulse width modulation (PWM) techniques for twophase 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-electricaldegree 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.

Cogging Torque Reduction of Single-Phase Brushless DC Motor With a Tapered Air-Gap Using Optimizing Notch Size and Position

This paper reports a stator shape optimization design for reducing the cogging torque of single-phase brushless dc (BLDC) motors by adopting an asymmetric air-gap to make them self-starting. A time step 2-D finite-element analysis (FEA) was carried out to analyze the characteristics of the single-phase BLDC motor. The Kriging model combined with Latin hypercube sampling and a genetic algorithm were used to reduce the cogging torque and maintain the efficiency and torque. As an optimal design result, the cogging torque of the optimal model was reduced. Finally, the analysis and optimal design results were confirmed by FEA as well as by experimental results.

Cogging torque reduction of single-phase brushless DC motor with a tapered air-gap using optimizing notch size and position

This paper reports a stator shape optimization design for reducing the cogging torque of single-phase brushless DC motor adopting an asymmetric air-gap to make them self-starting. Time step 2D-finite element analysis (FEA) was carried out to analyze the characteristics of a single-phase brushless DC motor. To reduce the cogging torque and maintain the efficiency and torque, the Kriging model based on Latin hypercube sampling (LHS) and a genetic algorithm (GA) were used. As an optimal design result, the cogging torque on the optimal model was reduced. Finally, the analysis and optimal design results were confirmed by FEA and the experimental results.

Optimal Design of Stator Shape for Cogging Torque Reduction of Single-phase BLDC Motor

This paper proposes the optimal design of stator shape for cogging torque reduction of single-phase brushless DC (BLDC) motor with asymmetric notch. This method applied size and position of asymmetric notches to tapered teeth of stator for single-phase BLDC motor. Which affects the variation of the residual flux density of the permanent magnet. The process of optimal design included the extraction of the sampling point by using Latin Hypercube Sampling(LHS), and involved the creation of an approximation model by using kriging method. Also, the optimum point of the design variables were discovered by using the Genetic Algorithm(GA). Finite element analysis was used to calculate the characteristics analysis and cogging torque. As a result of finite element analysis, cogging torque were reduced approximately 39.2% lower than initial model. Also experimental result were approximately 38.5% lower than initial model. The period and magnitude of the cogging torque were similar to the results of FEA.

A rotor shape design of interior PM motor for reducing cogging torque in electric air-conditioning system of HEV

This paper proposes a new design of rotor shape of the interior permanent magnet (IPM) motor used for the electric air-conditioning system of hybrid electric vehicles (HEV). The distribution of the residual magnetic flux density at the air gap was modified by the rotor surface shape and V-type magnet angle. The finite-element method (FEM) was applied to deterimne the optimal shape design of the rotor surface shape and V-type magnet angle because the IPM motor has extreme saturation in the rotor core. The validity of the proposed rotor shape optimization was confirmed by the manufactured IPM rotor core and the performance of the cogging torque was measured.

Study on reducing cogging torque of Interior PM Motor for electric vehicle

This paper proposes a new design of rotor shape of Interior Permanent Magnet Synchronous Motor (IPMSM) used for agricultural electric vehicle (AEV). The distribution of the residual magnetic flux density at the air gap is modified by rotor surface shape and V-type magnet angle. As a result, cogging torque and physical characteristic have been improved, and back electromotive force (back-EMF) of the suggested model has been improved to be closest to sine wave form compared to initial model. The validity of the proposed rotor shape optimization is confirmed by the manufactured IPM rotor core and measured the performance of the cogging torque.

Development of Single-phase Brushless DC Motor with Outer Rotor for Ventilation Fan

This paper is development of single-phase brushless DC motor with outer rotor for ventilation fan. Cogging torque causes the noise vibration to greatest impact on ventilation fan. Asymmetric notches are applied to tapered-teeth for cogging torque reduction of single-phase brushless DC motor. Initial model is notchless and proposed model is applied 2 asymmetric notches. The proposed method is proved motor characteristic through finite element analysis(FEA). Also, experimental results verify that the proposed model considerably reduces cogging torque and have the good sound quality in ventilation system.

Development of the 0.5kW motor & controller on air compressor for commercial hybrid or electric vehicles

This paper proposes a technical performance issue motors & controllers in the air compressors for electric or commercial vehicles. In the current existing air-compressor are using the belt-driven or DC motor-driven for commercial vehicles. Belt-driven type compressor has low efficiency characteristics. Depending on the speed and load changes is operating at low efficiency point. Using air compressor driven by DC motor demands for high energy efficiency. However, it is difficult to use them in practical application because the motor reliability issue arise abrasion of the brushes. In order to overcome this inconvenience, the driving modules using the Permanent magnet synchronous motor (PMSM) with high efficiency and reliability have recently drawn attention on the market with many applications in the public buses and commercial vehicles. The paper presents the designing in an all-in-one structure incorporating with the BLAC motor, controllers, and the mechanical part of the air compressor. Moreover, the analysis of these characteristics and performance tests are shown.