Hyuk Nam

Analysis of irreversible magnet demagnetization in line-start motors based on the finite-element method

This paper deals with the analysis for the irreversible demagnetization characteristics of a ferrite-type permanent magnet in the line-start motor using the two-dimensional finite-element method (2-D FEM). The demagnetizing currents are calculated from the transient analysis in the combination voltage equation with mechanical dynamic equation, and peak currents are applied to the irreversible demagnetization analysis computed by 2-D FEM. The nonlinear characteristic of the magnetic core is considered as well as that of a permanent magnet on the B-H curve in the analysis of irreversible demagnetization.

Loss distribution of three-phase induction motor fed by pulsewidth-modulated inverter

This paper deals with the loss distribution in a three-phase induction motor fed by a pulsewidth-modulated (PWM) inverter. The copper losses in the stator winding and rotor conductor bar, and iron loss except for mechanical and stray load losses, are computed by the variable time-stepping finite-element method (FEM) considering the switching action of the PWM inverter. The iron loss is evaluated by the frequency analysis of the magnetic flux density distribution using discrete Fourier transforms (DFT) and iron loss curves, which are provided by the manufacturer. Simulation results by the presented method are verified by the experiment results. Finally, the loss distribution of the PWM inverter type three-phase induction motor is compared with that of the conventional three-phase induction motor that is directly fed by the sinusoidal three-phase voltage source without any control devices.

A study on iron loss analysis method considering the harmonics of the flux density waveform using iron loss curves tested on Epstein samples

This paper deals with a study on an iron loss analysis method in the single-phase line-start permanent magnet synchronous motor. The iron loss is affected by the time rate of the change of magnetic flux density at the motor cores. The distribution and changes in magnetic flux densities of the motor are computed by using a two-dimensional finite element method. Discrete Fourier Transform (DFT) is used to analyze the magnetic flux density waveforms in each element of the analysis model. Iron losses in each element are evaluated using iron loss curves tested by an Epstein test apparatus. The total iron loss can be obtained by the summation of the iron losses in all the elements.

Optimal design of slotless-type PMLSM considering multiple responses by response surface methodology

This paper shows the usefulness of response surface methodology (RSM) for optimal design considering multiple responses. Moreover, full factorial design, one of the experimental design methods, is proposed to establish more reasonable and objective design area for applying RSM. The slotless-type permanent-magnet linear synchronous motor is optimized to develop larger average thrust and lower thrust ripple than the prototype, and the optimally designed one is manufactured. In the end, all analysis results are obtained by space harmonic method for fast and efficient design, and the validity of the results is verified by comparison with finite-element analysis and test

Analysis of single-phase line-start permanent-magnet motor considering iron loss and parameter variation with load angle

This paper presents analysis and design methodology of single-phase line-start permanent-magnet synchronous (LSPM) motors. The d-q-axes inductances of LSPM motors have a nonlinear variation according to the current and the load angle. The variation of d-q-axes inductances due to load angle is calculated by finite-element method in steady state. Iron loss is analyzed considering the harmonics of the flux density waveforms using iron loss curves. The validity of the presented analysis method considering the variation of the d-q-axes inductances is verified by comparison with experimental results.

Design to improve starting performance of line-start synchronous reluctance motor for household appliances

A single-phase line-start synchronous reluctance motor (LSynRM) has merits of low cost, high efficiency, and reliability. The LSynRM has the unbalanced magnetic circuit caused by flux barriers and various shapes of conductor bars. Thus, the motor can cause the unbalanced starting torque with the initial starting position of the rotor This paper presents the design to improve starting performance of the LSynRM for household appliances. Design variables are the number and the shape of the conductor bars. The motor is analyzed by finite element (FE) analysis. A SPIM (single-phase induction motor) for mass production, a prototype, and a designed model of LSynRM are manufactured and tested.

Rotor Design to Improve Starting Performance of the Line-start Synchronous Reluctance Motor

A single-phase line-start synchronous reluctance motor (LSSynRM) has merits of low cost, high efficiency and reliability. LSSynRM has an unbalanced magnetic circuit caused by flux barriers and various shapes of conductor bars when starting. Thus the motor may generate unstable starting torque in accordance with the initial starting position of the rotor. This paper presents the rotor design to improve starting performance of the LSSynRM. Design variables are the number and the shape of the conductor bars. This design result is compared with the initial prototype and single-phase induction motor.

Analysis and design methodology for single-phase line-start permanent magnet motor considering parameters variation on d-q axis vector diagram

This paper presents analysis and design methodology of single-phase line-start permanent magnet synchronous (LSPM) motors. The d-q axis inductances of LSPM motors have a nonlinear variation according to the current and the load angle. The variation of d-q axis inductances due to load angle is calculated by finite element method (FEM) in steady state. Iron loss is analyzed considering the harmonics of the flux density waveforms using iron loss curves. The validity of the presented analysis method considering the variation of the d-q axis inductances is verified by comparing with experimental results.

Design of pole-change single-phase induction motor for household appliances

This paper deals with the design of a pole change single-phase induction motor to reduce the harmonic components of the magnetic flux density in the air gap. The harmonics in the magnetic flux density distribution can have a significant detrimental effect on the characteristics of the machine such as crawling. In this paper, the magnetic flux density distribution is analyzed by analytical method and finite element method. Discrete Fourier transform is used to analyze the harmonics and the characteristics are calculated from the equivalent circuit considering the harmonic components. The winding arrangement for the harmonic reduction is designed from the optimization method and the harmonic reduction of the improved models is verified through the experimental results.

Design of pole change single-phase induction motor for household appliances

This paper deals with the design of a pole change single-phase induction motor to reduce the harmonic components of the magnetic flux density in the air gap. The harmonics in the magnetic flux density distribution can have a significant detrimental effect on the characteristics of the machine such as crawling. In this paper, the magnetic flux density distribution is analyzed by analytical method and finite element method. Discrete Fourier transform is used to analyze the harmonics and the characteristics are calculated from the equivalent circuit considering the harmonic components. The winding arrangement for the harmonic reduction is designed from the optimization method and the harmonic reduction of the improved models is verified through the experimental results.