• Proceedings of the KIPE Conference
• /
• 1998.10a
• /
• pp.630-635
• /
• 1998

This paper establishes in a new unified manner new mathematical models with core(iron) loss factor for two kinds of AC motors, induction and synchronous motors which are supposed to generate torque precisely or/and efficiently under vector controls. Our new models consist of three basic equations consistent with the others such as differential equation describing electromagnetic dynamics, torque equation describing torque generating mechanism, energy transmission equation describing how injected energy is wasted, saved or transmitted where all vector signals are defined in general frame of arbitrary instant angular velocity. It is clearly shown in our models that equivalent core-loss resistance can express appropriately and separately both eddy-current and hysteresis losses rather than mere vague loss. Proposed model of induction motor is the most compact in sense of the number of employed interior states and parameters. This compact model can also represent eddy-current and hysteresis losses of rotor as well as stator. For synchronous motor, saliency is taken into consideration. As well known model for cylindrical motor can be obtained directly from salient one as its special case.

• Journal of ILASS-Korea
• /
• v.28 no.2
• /
• pp.62-67
• /
• 2023

Recently, the global automobile industry is aiming for a transition from internal combustion locomotives to zero-emission vehicles. Electric vehicles powered by battery energy can operate at peak performance and improve fuel economy by applying multiple motors or multi-speed transmissions. In order to design a two-speed transmission, it is necessary to evaluate and analyze the application system and performance of electric vehicles. In this study, control performance optimization of a twostage battery electric vehicle equipped with an AMT-based automatic transmission was performed and performance according to control pattern changes was analyzed. In order to improve the operating efficiency of the motor, the shift control that sets the optimal operating point according to the vehicle speed and required torque was derived from the motor efficiency map. The performance of battery energy consumption and transmission loss energy according to the hysteresis interval was analyzed and optimized. The hysteresis interval applied to the optimal shift map acted as a factor in reducing the frequency and loss of shifts. It has been shown that keeping the hysteresis interval at about 4 km/h can reduce energy consumption while reducing the number of shifts.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.267-270
• /
• 2002

The accuracy and the dynamic bandwidth are the two most important indices that an inductive position sensor is evaluated with. Eddy currents and magnetic hysteresis affect both of these performance indices. As the modulation frequency of the sensor increases to improve the dynamic bandwidth, the effects of eddy currents and hysteresis also increases, which results in the loss of accuracy. In this paper, a magnetic circuit model of the differential inductive sensor is developed. This model includes the effects of hysteresis and eddy currents. Experimental results confirm the validity of the model. The model predicts that the eddy current effects are not significant below the modulation frequency of 50kHz, as long as the lamination thickness is adequate.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2006.05a
• /
• pp.493-495
• /
• 2006

The hysteresis characteristics of flux-lock reactor, which is an essential component of flux-lock type superconducting fault current limiter (SFCL), was investigated. The hysteresis loss of iron core in flux-lock type SFCL does not happen due to its winding's structure especially in the normal state. From the equivalent circuit for the flux-lock type SFCL and the fault current limiting experiments, the hysteresis curves could be drawn. Through the hysteresis curves together with the fault current level due to the inductance ratio for the 1st and 2nd windings, the increase of the number of turns in the 2nd winding of the flux-lock type SFCL had a role to prevent the iron core from saturation.

• Resources Recycling
• /
• v.13 no.6
• /
• pp.37-42
• /
• 2004

The power loss analysis was carried out for Ni-Cu-Zn ferrite sample with different content of NiO and ZnO. The power loss, Pcv decreases monotonically with increasing temperature and attains to a certain value at around 100~120 degrees Celsius. The frequency dependence of Pcv can be explained by Pcv~f$^n$, and n is independent of the frequency, f up to 1 MHz. The Pcv decreases with an increase in ZnO/NiO. The Pcv was separated to hysteresis loss(Ph) and residual loss(Pcv-Ph). The temperature characteristics and compositional dependence of Pcv can be attributed to the Ph, while Pcv-Ph is not affected by both temperature and ZnO/NiO. By analyzing temperature and composition dependence of Ph and initial permeability, ${\mu}_i$ like following equations could be formularized. ${\mu}_i{\mu}_0=I_s^2/(K_I+b{\sigma}_0{\lambda}_s)$ Wh=13.5(I$_s^2/{\mu}_i{\mu}_0)$ Where ${\mu}_0$ is permeability of vacuum, I$_s$ is saturation magnetization, K$_I$ is anisotropy constant, $s_0$ is internal heterogeneous stress, ${\lambda}_s$ is magnetostriction constant, b is unknown constant, and Wh is hysteresis loss per one cycle of excitation (Ph=Wh${\times}$f). Steinmetz constant of Ni-Cu-Zn ferrite, m=1.64~2.2 is smaller than that of Mn-Zn ferrites, which suggests the difference of loss mechanisms between these materials.

• Proceedings of the Korean Institute of Resources Recycling Conference
• /
• 2004.12a
• /
• pp.3-11
• /
• 2004

The power loss analysis was carried out for Ni-Cu-Zn ferrite samples with different content of NiO and ZnO. The power loss, Pcv decreases monotonically wi increasing temperature and attains to a certain value at around $100\~120$ degrees Celsius. The frequency dependence of Pcv can be explained by $Pcv\~f^n$', and n is independent of the frequency, f up to 1MHz. The Pcv decreases with an increase in ZnO/NiO. The Pcv was separated to hysteresis loss, Ph and residual loss, (Pcv-Ph). The temperature characteristics and compositional dependence of Pcv can be attributed to the Ph, while (Pcv-Ph) is not affected by both temperature and ZnO/NiO. By analyzing temperature and composition dependence of Ph and initial permeability, ${\mu}^i$ following equations could be formularized. $${\mu}_i{\mu}o=I_x\;^2/(K_1+bs_ol_s)\;\;\;\;(1)$$ $Wh=13.5(I_s\;^2/{\mu}_i{\mu}_o)\;\;\;\;(2)$$ Were ${\mu}_o$ is permeability of vacuum, $I_s$ saturation magnetization, $K_1$ anisotropy constant, $S_o$ internal heterogeneous stress, $I_s$, magnetostriction constant, b unknown constant. Wh hysteresis loss per one cycle of excitation (Ph: Wh*f). Steinmetz constant of Ni-Cu-Zn ferrites, $m=1.64\~2.2$ is smaller than the one of Mn-Zn ferrites, which suggests the difference of loss mechanism between these materials.

• Textile Coloration and Finishing
• /
• v.10 no.4
• /
• pp.37-44
• /
• 1998

The purpose of this study was to elucidate the effect of weight loss of polyethylene terephthalate(PET) fabrics on the mechanical properties such as bending and shear. In order to compare the effect of treatment machine on the mechanical properies of treated PET fabrics, PET fabrics were hydrolyzed with NaOH aqueous solution using Tank machine and Liquor flow machine, respectively. The results were as follows ： 1. The bending rigidity and shear stiffness of hydrolyzed PET fabric decreased markedly up to about 10％ weight loss regardless of treatment machines. At the above 10％ weight loss, the variation of these properties is nearly unchanged. In addition, the bending hysteresis and shear hysteresis also showed similar trend. 2. Weft density change of PET fabrics treated with Liquor flow machine decreased by 1pick/inch. It is assumed that this is attributed to the tension during the treatment of Liquor flow machine. On the other hand, the weft density change of PET fabrics treated with Tank machine is scarcely influeneced by the weight loss. While warp density of PET fabrics treated with Liquor flow machine had no change with weight loss, warp density of PET fabrics treated with Tank machine decreased by 6pick/inch due to the tension. 3. The bending rigidity and shear stiffness of PET fabrics hydrolyzed with liquor flow machine slightly higher than with Tank m/c at the above 10％ weight loss. It is assumed that this is caused by the increasement of the crossing pressure of warp and weft yarn and contact points of filaments in the yarns. Also, the bending and shear hysteresis of PET fabrics treated with Tank machine were higher than that of liquor flow machine.

• Proceedings of the KIEE Conference
• /
• 1998.11c
• /
• pp.1050-1053
• /
• 1998

To be applied to electrical equipment HTSC tapes have to endure external stress and so on. The critical current density has been shown depending on the mechanical properties. strain and bending stress. AC loss reduction is primary concern in the development of such high-efficiency equipment. AC losses in Bi-2223 silver-sheathed tapes, both single and multi-filamentary, were investigated by means of AC magnetization techniques. The results were compared with the hysteresis loss equation based on Bean model and the eddy current loss equation. The AC loss of the mono-filamentary tape was the hysteresis. On the contrary, the AC loss of the multi-filamentary tape was substantially dominated by the eddy current loss in the Ag matrix.

• Proceedings of the KIEE Conference
• /
• 1998.07a
• /
• pp.125-127
• /
• 1998

Superconducting tape is being developed for electrical equipment such as superconducting transformers and generators. AC loss reduction is primary concern in the development of such high-efficiency equipment. AC losses in Bi-2223 silver-sheathed tapes, both single and multi-filamentary, were investigated by means of AC magnetization techniques. The results were compared with the hysteresis loss equation based on Bean model and the eddy current loss equation. The AC loss, of the mono-filamentary tape was the hysteresis. On the contrary, the AC loss of the multi-filamentary tape was substantially dominated by the eddy current loss in the Ag matrix.

• Proceedings of the KIEE Conference
• /
• 1998.11b
• /
• pp.702-705
• /
• 1998

To be applied to electrical equipment HTSC tapes have to endure external stress and so on. The critical current density has been shown depending on the mechanical properties, strain and bending stress. AC loss reduction is primary concern in the development of such high-efficiency equipment. AC losses in Bi-2223 silver-sheathed tapes, both single and multi-filamentary, were investigated by means of AC magnetization techniques. The results were compared with the hysteresis loss equation based on Bean model and the eddy current loss equation. The AC loss of the mono-filamentary tape was the hysteresis. On the contrary, the AC loss of the multi-filamentary tape was substantially dominated by the eddy current loss in the Ag matrix.