Gyu-Won Cho

The Estimation Method Comparison of Iron Loss Coefficients through the Iron Loss Calculation

A new calculation method for iron loss coefficients is proposed by using the Steinmetz equation from Epstein data. The hysteresis loss must have linear characteristic according to the frequency. However, the existing iron loss coefficients are defined by formula of frequency. In this case, the hysteresis loss has non-linear characteristics by frequency. So, in this paper, the iron loss coefficients were defined by a function of the magnetic flux density, and the iron loss calculation is applied for Interior Permanent Magnet Synchronous Motor(IPMSM) of 600(W) and 200(W). The iron loss calculation results and the experimental results are compared according to the various materials.

The Improved Design of Double Sided Coreless PMLSM with Consideration of Rising Winding Temperature

This work deals with the optimal design of a coreless PMLSM (Permanent Magnet Linear Synchronous Motor) with consideration of rising winding temperature. The temperature distribution caused by copper loss in the coreless PMLSM was analyzed using a FEM (Finite Element Method). The thrust and current density where the winding temperature reaches the allowable temperature were calculated. The optimal model provides maximum thrust per unit weight.

The Design of Flux Barrier for Improvement of Demagnetization Endurance in BLDC Motor

Generally, the motor inside vehicle is exposed to highly ambient temperature and large vibration according to repeatedly starting and stopping during very short time. So, in this paper, the rotor shape design was performed to improve demagnetization endurance by considering the starting current of the Brushless DC (BLDC) Motor through the Finite Element Method(FEM). As a result, the end of Permanent Magnets (PMs) in the basic model was occurring a partial irreversible demagnetization by starting current. To solve this problem, the installing flux barriers were limited to flux line on the core. Accordingly, demagnetization endurance and operating characteristics were improved.

Optimization of rotor shape for constant torque improvement and radial magnetic force minimization

The design of notch and barrier was optimized in order to improve the characteristics of constant torque while minimizing the cogging torque that occurs as a result of teeth and slot structure. The barrier was installed in order to minimize the cogging torque and torque ripple by finite element method (FEM) with a reduced barrier width toward the center of magnetic pole. The position and width of notch, which can offset cogging torque, can be calculated with energy distribution of air-gap using Fourier series. The optimized model demonstrates a 60% decrease in the cogging torque, a 75.3% decrease in the torque ripple and a 3% increase in the operating torque when compared with the basic model.

The Design of Radial Magnetic Force Equilibrium for Reduction of Vibration and Noise in IPM Type BLDC Motor

In this paper, the Radial Magnetic Force(RMF) and cogging torque which cause vibration and noise in IPM type BLDC motor were analyzed. The cogging torque and RMF cause electromagnetic vibration. So, a notch was installed for the equilibrium of RMF and cogging torque reduction. The notch was analyzed by using a Fourier Series for the energy distribution of the air-gap. The equilibrium of RMF and the reduction of cogging torque were performed by a Design Of Experiment(DOE) with the notch. Also, operating characteristics and efficiency were analyzed and compared.

The Iron loss Estimation of IPMSM According to Current Phase Angle

Variable iron loss as function of current phase angle of Interior Permanent Magnet Synchronous Motor(IPMSM) was calculated through Curve Fitting Method(CFM). Also, a magnetic flux density distribution of iron core according to current phase angle was analyzed, and an iron loss calculation was performed including harmonic distortion. The experiment was performed by production of non-magnetizing model for the separation of mechanical loss, and the iron loss was calculated by the measurement of input using power analyzer and output power using dynamometer. Some error was generated between experimental results and calculation value, but an iron loss diminution according to current phase angle followed a same pattern. So, errors were generated by measurement, vibration, noise, harmonic distortion loss, etc.

The Maximum Efficiency Driving in IPMSM by Precise Estimation of Current Phase Angle

In this paper, the equivalent circuit for the efficiency calculation by precise estimation of the linkage flux, inductance and iron loss resistance was calculated accurately. In addition, the driving characteristics according to the current phase angle are analyzed and the maximum efficiency point is calculated. And then, analyzed and experimental values of the efficiency were compared. So, causes of error were expected to be vibration and noise by harmonic distortion of the voltage and current, and mechanical loss of dynamometer. In addition, the driving characteristics according to the current phase angle are analyzed and the maximum efficiency point is calculated.

The stabilization of cogging torque variation by manufacturing tolerances

The theoretical cogging torque by the electromagnetic analysis is constant due to the ideal shape rotor and stator. In addition, this phenomenon is a very big clue in the cogging torque reduction. In this paper, the cogging torque according to a mass-production tolerance was considered by experimental review. Therefore, we propose an improvement of the tolerances in the housing for a stabilization of the cogging torque variation.

The design of flux barrier for improvement of demagnetization endurance in BLDC Motor

Generally, the motor inside vehicle is exposed to highly ambient temperature and large vibration according to repeatedly starting and stopping during very short time. So, in this paper, the rotor shape design was performed to improve demagnetization endurance by considering the starting current of the Brushless DC (BLDC) Motor through the Finite Element Method(FEM). As a result, the end of Permanent Magnets (PMs) in the basic model was occurring a partial irreversible demagnetization by starting current. To solve this problem, the installing flux barriers were limited to flux line on the core. Accordingly, demagnetization endurance and operating characteristics were improved.

The Optimal Design of Single Sided PMLSM for Considering Winding Temperature Rising according to Thickness of Teeth

This research deals with design of the maximum thrust density with considering winding temperature rise of single-sided PMLSM. The temperature rise of winding which caused to machine characteristics such as copper loss, iron loss and efficiency was analyzed by FEM. The maximum allowable current density was calculated within the allowable temperature. The effects of loss and efficiency according to temperature characteristic were confirmed.