Jin Hur

A Novel Cogging Torque Reduction Method for Interior Type Permanent Magnet Motor

This paper presents a novel design method to reduce cogging torque of interior type permanent magnet (IPM) motor. In the design method, the optimal notches are put on the rotor pole face, which have an effect on variation of permanent magnet (PM) shape or residual flux density of PM. Through the space harmonics field analysis, the positions of notches are found and the optimal shapes of notches are determined by using finite element method (FEM). The validity of the proposed method is confirmed by experiments.

Vibration Reduction of IPM-Type BLDC Motor Using Negative Third Harmonic Elimination Method of Air-Gap Flux Density

This paper proposes a harmonic elimination method for vibration and noise minimization of an interior-type permanent-magnet motor, achieved by alternating the distribution of the radial flux density. The minimization of vibration and noise is realized by forming optimal notches corresponding to the shape of the magnetic field on the rotor pole face. The variations in vibration are computed by a nonlinear finite element method, and the validity of the analysis and rotor shape design is confirmed by performing vibration and performance experiments.

Finite Element Computation of Magnetic Vibration Sources in 100 kW Two Fractional-Slot Interior Permanent Magnet Machines for Ship

The design of an interior permanent magnet (IPM) machine, in particular, its pole and slot combination, determines the nature of its magnetic forces, which influences not only the torque but also acoustic noise and vibration characteristics. Vibrations can shorten bearing life and are an especially important parameter in marine applications, which have strict regulations such as on electromagnetic compatibility. In this study, two-dimensional(2D) finite element analysis (FEA) was used to model magnetic vibration sources in two 100-kW marine fractional-slot IPM machines with different pole and slot combinations (8 pole-12 slot and 10 pole-12 slot). The magnetic forces were calculated according to rotor position, current phase angle, and load. The results are validated by experiments.

Stator and Rotor Shape Designs of Interior Permanent Magnet Type Brushless DC Motor for Reducing Torque Fluctuation

This paper presents the stator and rotor shape designs in interior permanent magnet (IPM) type brushless dc (BLDC) motor for reducing torque fluctuation. The partly enlarged air-gap made by rotor unequal out diameter and stator core structure with pole shoe modification is introduced. The torque ripple reduction is achieved by upgrading torque value at minimum torque position and their detail characteristics are compared. The final stator and rotor shape of IPM type BLDC motor is decided by design of experiments (DOE) process. The magnetic field and torque characteristics are analyzed by 2 dimensional (2D) finite element analysis (FEA) and their performances are validated by experimental results.

Analysis of radial forces in 100kW IPM machines for ship considering stator and rotor eccentricity

The purpose of this paper is to provide the radial force and vibration mode comparison between two large interior permanent magnet machines (IPM) with different pole-slot combination considering stator and rotor eccentricity. Due to the punching tolerance, the mixed eccentricity of air-gap is inevitable. It will generate the asymmetric magnetic flux density in air-gap, which makes the unbalanced magnetic pull and vibration. The study is focused on the unbalanced magnetic force and their harmonics according to eccentricity condition such as static, dynamic and mixed. When the high vibration is produced especially resonance, the obtained results provide a clue what eccentricity condition occurs in the machine.

Design and optimization of high torque, low ripple switched reluctance motor with flux barrier for direct drive

While switched reluctance motors (SRM) have good performances, such as high torque, high speed, and high reliability, SRM has serious disadvantage of large torque ripple. In order to reduce the torque ripple and improve the average torque of the motor, this paper proposes a new type of SRM with inserted flux barriers into the rotor. The proposed type SRM is simulated for various configurations of the flux barriers and a shape optimization of the barrier has been carried out additionally. The performances of proposed type of SRM were confirmed by finite element analysis and experimentation and advantages and limitations of using flux barriers in SRM design for high torque are discussed. From the analysis results, it must be noted that the proposed type has great advantage over the conventional type toward trend of higher torque per a volume. Calculated and experimental results are presented, to validate the inserting the flux barriers and the resulting improvements.

The shape design of interior type permanent magnet BLDC motor for minimization of mechanical vibration

This paper presents a rotor shape optimization of interior type permanent magnet (IPM) motor for vibration minimization. The vibration of permanent magnet motor is generated by cogging torque, radial force and commutation torque ripple which are electromagnetic source of vibration. In order to minimize the vibration, the optimal notches are put on the rotor pole face and the arc type pole face is applied. The variations of cogging torque and radial force of each model vibration frequency are computation by finite element method (FEM) and the validity of the analysis and rotor shape design is confirmed by vibration experiments.

Characteristic analysis of IPM type BLDC motor considering the demagnetization of PM by stator turn fault

A stator turn fault in a symmetrical three-phase machine cause a large circulating current to flow and subsequently generated excessive heat in shorted turns, generate irregular control current of the three phase leads to demagnetization. The demagnetization of PM occurred distortion of air-gap magnetic flux distribution caused deterioration of their torque, mechanical vibration etc. In this paper, for minimization of mechanical vibration, the optimal PM shape is designed and the effect of the circulating current in shorted turns on the demagnetization of PM and motor performance is analyzed. For this analysis, this paper developed a FE-based simulation model with a stator turn fault modeling. The demagnetization phenomenon in IPM type BLDC is analyzed under continuously controlled 3-phase input current considering the circulating current in shorted turn using the developed transient analysis method.

Analysis and Design of Slotted Tubular Linear Actuator for the Eco-Pedal System of a Vehicle

This paper presents the design and analysis of a linear actuator for vehicle Eco-Pedal system. To prevent the excessive gas consumption for fuel-efficient vehicle the electric actuator produces a counter force to the vehicles pedal to be pressed stiffly. Major performances of the actuator are required such as a high force density and a low detent force. In this paper, the analysis and design technique of the actuator thrust is based on an analytical method, and the advisability of the design result is verified with both the result of the experiment and the result of the finite element method.

Design guideline of DC distribution systems for home appliances: Issues and solution

In this paper, 5kW DC distribution system test-bed is designed to prove feasibility of DC distribution system and find problems and solutions when DC distribution is introduced. And availability of spark reduction method using initial charging circuit and arc reduction method using freewheeling diode is verified. In conclusion, we conduct empirical research applying simultaneous and actual load to DC distribution test-bed.