• Title, Summary, Keyword: temperature of permanent magnet

Search Result 110, Processing Time 0.04 seconds

A Torque Compensation Method Considering Temperature Variation of SPMSM

  • Jung, Tae-Uk;Park, Chang-Seok
    • Journal of Electrical Engineering and Technology
    • /
    • v.13 no.1
    • /
    • pp.160-167
    • /
    • 2018
  • This paper analyzed the effect of temperature on the permanent magnet flux and output torque. The major parameter which will impact the torque control accuracy of a surface mounted permanent magnet motor is the variation of the permanent magnet temperature. In addition, the temperature variation of the permanent magnet will also influence the maximum torque per ampere of the motor. To analyze the effect of temperature on the permanent magnet, the rotor of the motor was directly heated to measure the temperature and the permanent magnet flux was measured. As a result, the output torque of the motor decreases as the temperature of the rotor permanent magnet increases. Therefore, this paper proposes a technique to compensate the phase current of the motor by estimating permanent magnet flux, and it is proved through theoretical basis and several experiments.

The Practical Method and Experimental Verification of Temperature Estimation in the Permanent Magnet of Electric Machine

  • Kang, Kyongho;Yu, Sukjin;Lee, Geunho;Lee, Byeong-Hwa
    • Journal of Magnetics
    • /
    • v.20 no.4
    • /
    • pp.421-426
    • /
    • 2015
  • This paper presents a practical method for estimation of average temperature in the permanent magnet (PM) of electric machine by using finite element analysis (FEA) and dynamo load experiment. First of all, the temperature effect of PM to the torque has been employed by FEA in order to evaluate the Temperature-Torque characteristic curve. The 1st order polynomial equation which is torque attenuation coefficient is derived by the FEA result of the Temperature-Torque curve. Next, torque saturation test with constant current condition is performed by dynamo load experiment. Then, the temperature trend can be estimated by adding the initial starting temperature using the torque attenuation coefficient and torque saturation curve. Lastly, estimated temperature is validated by infrared thermometer which measures temperature of PM surface. The comparison between the estimated result and experimental result gives a good agreement within a deviation of maximum $8^{\circ}C$.

Experimental investigation on the room temperature active magnetic regenerator with permanent magnet array (영구자석 배열을 이용한 능동형 자기재생 냉동기에 대한 실험적 연구)

  • Kim, Young-Kwon;Jeong, Sang-Kwon
    • Proceedings of the SAREK Conference
    • /
    • /
    • pp.186-191
    • /
    • 2008
  • In this study, a room temperature AMRR (Active magnetic regenerative refrigerator) was fabricated, and experimentally investigated. Gadolinium (Gd) was selected as a magnetic refrigerant with Curie temperature of 293 K. Permanent magnet was utilized to magnetize and demagnetize the AMR. To produce large magnetic field above 1 T in the magnetic refrigeration space, a special arrangement of permanent magnets, so called Halbach array, is employed. Sixteen segments of the permanent magnets magnetized different direction, constitute a hollow cylindrical shaped permanent magnet. The AMR is reciprocated along the bore of the magnet array and produces cooling power. Helium is selected as the working fluid and a helium compressor is utilized to supply helium flow to the regenerator. The fabricated AMRR has different structure and compared to a convectional AMRR since it has an additional volume after the regenerator. Therefore, the cooling ability is generated not only by magnetocaloric effect of magnetic refrigerant but also by the pulse tube effect. It is verified that the cooling ability of AMR is increased due to the magnetocalric effect by the fact that the temperature span becomes $16^{\circ}C$ while the temperature span is only $8^{\circ}C$ when the magnetic field is not applied to the regenerator.

  • PDF

Research on the Influence of Inter-turn Short Circuit Fault on the Temperature Field of Permanent Magnet Synchronous Motor

  • Qiu, Hongbo;Yu, Wenfei;Tang, Bingxia;Yang, Cunxiang;Zhao, Haiyang
    • Journal of Electrical Engineering and Technology
    • /
    • v.12 no.4
    • /
    • pp.1566-1574
    • /
    • 2017
  • When the inter-turn short circuit (ITSC) fault occurs, the distortion of the magnetic field is serious. The motor loss variations of each part are obvious, and the motor temperature field is also affected. In order to obtain the influence of the ITSC fault on the motor temperature distribution, firstly, the normal and the fault finite element models of the permanent magnet synchronous motor (PMSM) were established. The magnetic density distribution and the eddy current density distribution were analyzed, and the mechanism of loss change was revealed. The effects of different forms and degrees of the fault on the loss were obtained. Based on the loss analysis, the motor temperature field calculation model was established, and the motor temperature change considering the loop current was analyzed. The influence of the fault on the motor temperature distribution was revealed. The sensitivity factors that limit the motor continuous operation were obtained. Finally, the correctness of the simulation was verified by experiments. The conclusions obtained are of great significance for the fault and high temperature demagnetization of the permanent magnet analysis.

Temperature rise calculation of a disc type motor with heat source method (열회로 방식에 의한 Disc type motor의 온도상승 계산)

  • Park, Chang-Soon;Chang, Ki-Chan
    • Proceedings of the KIEE Conference
    • /
    • /
    • pp.43-46
    • /
    • 1991
  • Nd-Fe-B Permanent Magnet, which is recently more used, has some advantages in comparison with other permanent magnet. However, for the Nd-Fe-B has higher RTC(reversible temperature coefficient), property of the Nd-Fe-B magnet is changed by temperature rise. In this paper temperature rise of a disc type motor is calculated using a heat source network method.

  • PDF

Change of Operating Characteristics of Latching Relay with Temperature (래칭 릴레이의 온도에 따른 동작 특성 변화)

  • Ryu, Jae-Man;Jin, In-Young;Huh, Chang-Su
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.30 no.8
    • /
    • pp.520-524
    • /
    • 2017
  • Electrical relay in an essential part of smart grids, electrical vehicles, and LED lightning systems. Therefore, studying relay reliability is important. Relays using permanent magnet actuators (PMAs), which are energy efficient, are also in the spotlight. However, most of the permanent magnets used in PMAs have a characteristic wherein the magnetic flux decreases as the temperature increases. When the magnetic flux is reduced, the force acting on the actuator is reduced. Therefore, in this study, we measured the decrease in the relay operating speed with permanent magnet reduction due to temperature rise. In addition, changes in the bouncing phenomena due to magnetic flux reduction were analyzed. As a result, the operating speed of the relay has decreased and the bouncing phenomenon has not significantly changed.

Eddy Current Loss Analysis in Radial Flux Type Synchronous Permanent Magnet Coupling using Space Harmonic Methods (공간고조파법을 이용한 반경방향 영구자석을 갖는 자기커플링의 와전류 손실 해석)

  • Min, Kyoung-Chul;Kang, Han-Bit;Park, Min-Gyu;Cho, Han-Wook;Choi, Jang-Young
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.63 no.10
    • /
    • pp.1377-1383
    • /
    • 2014
  • This paper deals with eddy current loss of magnetic coupling with radial permanent magnet (PM) using analytical method such as a space harmonic method. Superposition of two kinds analysis model is used to analyze eddy current loss induced in inner PM and outer PM of magnetic coupling. When the eddy current is induced, the environmental temperature increases, and the permanent magnet(PM) characteristics are degraded because the performance of PM is greatly influenced by temperature rise. Hence, the calculation of eddy current loss becomes an important factor in the magnetic coupling. In order to analyze eddy current loss, first, on the basis of the magnetic vector potential and two-dimensional(2-D) polar-coordinate system, the magnetic field solutions of the radial magnetized PM are obtained. And we obtain the analytical solutions for the eddy current density produced by permanent magnet. Lastly, analytical solutions for eddy current loss are derived by using equivalent, electrical resistance calculated from magnet volume and analytical solution for eddy current density. This analytical results are validated by comparing with the 2-D finite element analysis (FEA).

Overhauser dynamic nuclear polarization for benchtop NMR system using a permanent magnet of 1.56 T

  • Lee, Yeon-seong;Lim, Duk-Young;Shim, Jeong Hyun
    • Journal of the Korean Magnetic Resonance Society
    • /
    • v.23 no.3
    • /
    • pp.81-86
    • /
    • 2019
  • Overhauser dynamic nuclear polarization (O-DNP) has been an efficient method to boost the thermal nuclear polarization in liquids at room temperature. However, O-DNP for a benchtop NMR using a permanent magnet has remained unexplored yet. In this work, we report the development of an O-DNP system adopting a permanent magnet of 1.6 T. Q-band (~43 GHz) high-power amplifier produced 6 W microwave for saturation. Instead of resonator, we used an open-type antenna for the microwave irradiation. For several representative small molecules, we measured the concentration and frequency dependences of the enhancement factor. This work paves the way for the development of a benchtop DNP-NMR system overcoming its disadvantage of low quality signal when using a permanent magnet.

Analysis of Permanent Magnet Eddy Current Loss by Permanent Magnet Attaching Method of Magnetic Gears (마그네틱 기어의 영구자석 부착방법에 따른 영구자석 와전류손실 분석)

  • Park, Eui-Jong;Kim, Sung-Jin;Jung, Sang-Yong;Kim, Yong-Jae
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.66 no.6
    • /
    • pp.911-915
    • /
    • 2017
  • Recently, there has been an increasing interest in the non-contact power transmission method of magnetic gears. Since there is no mechanical contact, noise caused by friction can be reduced, and even if a sudden large force is applied, the impact of the gear is close to zero. Further, since the power is transmitted by the magnetic flux, it has high reliability. However, there is a problem that a loss due to a magnetic field due to use of a magnetic flux. The loss caused by the magnetic field of the magnetic gear is a joule loss called eddy current loss. In addition, the eddy current loss in the magnetic gear largely occurs in the permanent magnet, but it is a fatal loss to the permanent magnet which is vulnerable to heat. Particularly, magnetic gears requiring high torque density use NdFeB series permanent magnets, and this permanent magnets have a characteristic in which the magnetic force decreases as temperature increases. Therefore, in this paper, the eddy current loss of the permanent magnet according to the permanent magnet attaching method is analyzed in order to reduce the eddy current loss of the permanent magnet. We have proposed a structure that can reduce the eddy current loss through the analysis and show the effect of reducing the loss of the proposed structure.

A Study On Maximum Torque Of Interior Permanent Magnet Synchronous Motors Considering Temperature Variation (영구자석 동기전동기의 온도변화를 고려한 최대토오크에 관한 연구)

  • Hyun, Dong-Suk;Sim, Joon-Suk;Baek, Kwang-Sun;Kim, Nam-Joon
    • Proceedings of the KIEE Conference
    • /
    • /
    • pp.600-603
    • /
    • 1989
  • In this paper, maximum torque per current ratio of the interior permanent magnet synchronous machines including compensation of Ne-Fe-B magnets in negative temperature sensitivity is described. This compensation can be achieved by measuring of motor temperature only.

  • PDF