• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.42-47
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• 2014

The use of BLDC motor in Vehicle and industrial field, it is operated by continuous and intermittent driving. When the intermittent driving is occurred by the rise and fall of temperature repeatedly, it was represented by different characteristics in case of continuous driving. So, it is very important that heat source estimation according to the duty ratio. In this paper, temperature characteristics according to the operating method of BLDCM was calculated by using the thermal equivalent circuit, and the validity of the study was demonstrated as compared to the calculated and experimental results.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.11
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• pp.951-956
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• 2014

Steady-state thermal analysis was performed on a thermal equivalent circuit to determine the heat generation during operation of an interior permanent magnet synchronous motor (IPMSM). New machines must be compact and light and produce high torque density under extreme environmental conditions. Thermal analysis of an IPMSM is particularly important because excessive heat generated from the core and magnet reduces the IPMSM's output and has adverse effects on the durability. Therefore, steady-state thermal analysis of an IPMSM was performed for changes in the design variables using a thermal equivalent circuit. The changed variables were the axis length and thickness of the housing. The results of this method were compared with those of the finite element method to verify the accuracy and reliability.

• Progress in Superconductivity and Cryogenics
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• v.12 no.1
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• pp.61-65
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• 2010

To develop the thermal analysis method for the thermal behavior of HTS power cable system, cooled with sub-cooled liquid nitrogen, new thermo dynamic model for HTS cable system is introduced. The introduced thermal model is mainly modified from the thermal circuit following to IEC60287 for underground power cable systems such as XLPE or paper wrapped insulation cables. The thermal circuits for HTS cables are similar to the forced cooled underground cable system but the major thermal parameters and the configuration is apparently different to the normal cable systems so there has been no proposals in this field of analysing method. In this paper, 154kV HTS cable system has been introduced as an aspects of thermal models and a thermal circuit is proposed for the fundamentals on the dynamic rating systems for the HTS cable system. By using the thermal circuit developed in this paper, the optimal controls on the sub-cooling system's capacity become possible and it is expected to make the efficiency of HTS cable higher than conventional static controls.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.1063-1066
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• 2002

An equivalent circuit for the superconductor flux flow transistor(SFFT) was combined with high temperature cooling device, based on the analogy between thermal and electrical variables using the high-temperature superconductor(HTS), is proposed. The device is composed of parallel weak links with a nearby magnetic control line. A model has been developed that is based on solving the equation of motion of Abrikosov vortices subject to Lorentz viscous and pinning forces as well as magnetic surface barriers. The use of thermal models the global performance of thermal cooling circuit and signal system to be checked by using electrical circuit analysis programs such as SPICE.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.320-323
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• 2005

This paper discusses heat problem of IC, which composes the electronic instruments, to guarantee reliability of electronic instruments. And also proposes the unified equivalent model for various electronic instrument products to guarantee reliability and life of its parts. Because electronic instruments are down sizing and operated with high frequency, the internal temperature of electronic instruments is rising steadily. The internal temperature of the electronic instruments gives a big effect to electronic instrument's reliability and life. The semiconductor parts are the representative heat generation parts because of its complicated function, high frequency and high density. Consequently, guaranteeing reliability and life of electronic semiconductor is the important start point in securing the reliability and life of the electronic instrument product. Unfortunately, there are many factors, which affect heat dissipation efficiency. The heat dissipation efficiency follows the environment where the electronic instrument products are used. Therefore it is very difficult to define reliability and life of the electronic manufactures. Electronic instrument products are composed of printed circuit board (PCB), integrated circuit (IC), resistance, and capacitor and so on. And there are superposed thermal resistances, because the parts are arrayed on the printed circuit board (PCB), Therefore the total thermal resistance is variable. Consequently it cannot have same thermal model for each electronic instrument products. In the next part, we propose the unified equivalent model for various electronic instruments. And using the proposed equivalent model proofs the method for analysis reliability of electronic parts.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.1225-1226
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• 2012

• JSTS:Journal of Semiconductor Technology and Science
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• v.10 no.4
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• pp.300-308
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• 2010

This paper describes the development of a low-power electrocardiogram (ECG) touch sensor intended for the use with two dry metal electrodes. An equivalent ECG extraction circuit model encountered in a ground-free two-electrode configuration is investigated for an optimal sensor read-out circuit design criteria. From the equivalent circuit model, (1) maximum sensor resolution is derived based on the electrode's background thermal noise, which originates from high electrode-skin contact impedance, together with the input referred noise of instrumentation amplifier (IA), (2) 60 Hz electrostatic coupling from mains and motion artifact are also considered to determine minimum requirement of common mode rejection ratio (CMRR) and input impedance of IA. A dedicated ECG read-out front end incorporating chopping scheme is introduced to provide an input referred circuit noise of 1.3 ${\mu}V_{rms}$ over 0.5 Hz ~ 200 Hz, CMRR of IA > 100 dB, sensor resolution of 7 bits, and dissipating only 36 ${\mu}W$. Together with 8 bits synchronous successive approximation register (SAR) ADC, the sensor IC chip is implemented in 0.18 ${\mu}m$ CMOS technology and integrated on a 5 cm $\times$ 8 cm PCB with two copper patterned electrodes. With the help of proposed touch sensor, ECG signal containing QRS complex and P, T waves are successfully extracted by simply touching the electrodes with two thumbs.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.11
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• pp.1558-1563
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• 2015

In this paper, temperature characteristic analysis was performed by using a thermal equivalent circuit. To suppress the temperature rising, the cooling fan was installed in rotor. The temperature of permanent magnet was reduced from 66[$^{\circ}C$] to 55[$^{\circ}C$] by installing the fan. The temperature of the permanent magnets is difficult to measure. Therefore the temperature of end winding was measured directly by the thermo couple. The validity of this study was demonstrated as compared the calculated results with experimental ones.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.82-84
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• 1993

A method for simulating general characteristics and temperature characteristics of magnetizing fixture coil of the capacitor discharge impulse magnetizer-magnetizing fixture system using SPICE is presented. This method has been developed which can aid the design, understanding and inexpensive, time-saving of magnetizing circuit. As the detailed characteristics of magnetizing circuit can be obtained, the efficient design of the magnetizing circuit which produce desired magnet will be possible using our SPICE modeling. Especially, The knowledge of the temperature of the magnetizing fixture is very important to forecast the characteristics of the magnetizing circuits tinder different conditions. The capacitor voltage was not raised above 810[V] to protect the magnetizing fixture from excessive heating. The temperature estimation method uses multi-lumped model with equivalent thermal resistance and thermal capacitance.

• Journal of the Korean Society for Railway
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• v.16 no.2
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• pp.99-103
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• 2013

In this paper, research on the thermal analysis method is reported for the characterization of heat generation while operating an Interior Permanent Magnet Synchronous Motor (IPMSM) for railway vehicles. Efficient cooling of the heat generated in the IPMSM is important because the excessive heat generated from the winding, core and permanent magnets increases the difficulty of continuously operating an IPMSM over long time periods. Therefore, in this study, in order to analyze the heat generation characteristics of the IPMSM for advanced research in the application of IPMSMs to cooling devices, the heat transfer coefficients for each component of the IPMSM were derived and the thermal equivalent circuit was configured to perform thermal analyses. Finally, the validation of the suggested thermal analysis method was performed through comparison with the heat experimental data of an IPMSM prototype.