• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.160-167
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• 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.

• Proceedings of the KIPE Conference
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• 2018.11a
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• pp.175-176
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• 2018

This paper presents a method to estimate the parameter of permanent magnet synchronous motor using a least squares method. The approximate solution of the linear simultaneous equations is obtained by the pseudoinverse least squares method of the input current and output voltage data of the current controller. It is possible to obtain the current response of the same bandwidth to the general control target by using the Pole-zero Cancellation technique. This paper verifies the performance of the proposed method by comparing the results of estimation of parameters of different motors by simulation.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1832-1837
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• 2011

This paper presents the optimal permanent magnet shape on the rotor of an interior permanent magnet motor to reduce the core losses and improve the performance. As permanent magnet has conductivity inherently, it causes huge amount of eddy current losses by the slot harmonics with concentrated winding. This loss is roughly 100 times larger than that of distributed winding in high speed operation and it cannot be ignored, especially on traction motors. Each eddy current loss on permanent magnet has been investigated in detail by using FEM(Finite Element Method) instead of EMCNM(Equivalent Magnetic Circuit Network Method) in order to consider saturation and non-linear magnetic property. Simulation-based DOE(Design Of Experiment) is also applied to avoid large number of analyses according to each design parameter and consider expected interactions among parameters. Consequently, the optimal design to reduce the core loss on the permanent magnet while maintaining or improving motor performance is proposed by an optimization algorithm using regression equation derived and lastly, the core loss reduction on the proposed shape of the permanent magnet is verified by FEM.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.8
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• pp.373-380
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• 2003

This paper consists of a study in post-assembly magnetization of LSPM (Line Start Permanent Magnet Motor). Recently, LSPM is noted as an alternative to the induction motor because it offers a very high efficiency and unity power factor, And it is necessary for permanent magnets to be magnetized by means of post-assembly magnetization in LSPMS because of the manufacturing cost involved. The manufacturing process is also simpler in post-assembly magnetization than in pre-assembly magnetization. Generally, permanent magnet motors are magnetized by their own stator coil or by magnetizing fixtures. However, the permanent magnet in a LSPM is scarcely magnetized by using them because of the eddy current of the rotor bar. Hence, it is necessary to design a magnetizing fixture that overcomes this problem. In this paper, the author analyses the post-assembly magnetization of a LSPM and proposes a method for designing the magnetizing fixture. The method that the author proposes is to make the number of coil turns greater in order to reduce the effect of the eddy current of the rotor bars.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.3
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• pp.215-223
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• 2005

An electrical machine for a high-speed flywheel for energy storage in large hybrid electric vehicles is described. Design choices for the machine are motivated: it is a radial-flux external-rotor permanent-magnet synchronous machine without slots in the stator iron and with a shielding cylinder. An analytical model of the machine is briefly introduced whereafter optimization of the machine is discussed. Three optimization criteria were chosen: (1) torque; (2) total stator losses and (3) induced eddy current loss on the rotor. The influence of the following optimization variables on these criteria is investigated: (1) permanent-magnet array; (2) winding distribution and (3) machine geometry. The paper shows that an analytical model of the machine is very useful in optimization.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.700-702
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• 2002

High-speed brushless permanent magnet machines are good for compressor and aerospace applications, etc. since they are conductive to high efficiency, high power density, small size and low weight. This paper presents 3-phase permanent magnet brushless AC Motor designed for the high-speed drives. Especially, we predicted the inverter high frequency pulse width modulation (PWM) switching caused eddy current losses in a permanent magnet brushless dc motor.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.11
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• pp.109-115
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• 2012

Recently, permanent magnet synchronous motor are applied to various applications. Because of the importance of high reliable operation in these areas, many research related to the fault detection and diagnosis of inverter system are conducted. So, a faults model for an inverter-driven permanent magnet synchronous motor is studied by using the fault current of motor according to switch open, which can be effectively used for performance evaluation of the diagnostic algorithm. And fault of the permanent magnet synchronous motor inverter drive system is divided into four types. The feasibility of the proposed method are improved by simulation and experiment.

• Proceedings of the KIEE Conference
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• 2000.11b
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• pp.277-279
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• 2000

This paper proposes two kinds of the eddy current brake which uses permanent magnet. The one, like multipolar excitation consists of hexahedron shape of a segmented permanent magnetic and iron situated in the air-gap. The other, like multipolar excitation consists of only a segmented permanent magnetic. We use a finite element method to compute the flux distribution in the model. Also, we use the Galerkin-FEM with linear interpolation function may oscillate between the adjacent nodes to calculate the braking and attraction force. The advantages of the Halbach array are discussed.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.256-261
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• 2017

This paper deals with the experimental evaluation on power loss of a double-side permanent magnet synchronous motor/generator (DPMSM/G) applied to a flywheel energy storage system (FESS). Power loss is one of the most important problems in the FESS, which supplies the electrical energy from the mechanical rotation energy, because the power loss decreases the efficiency of energy storage and conversion of capability FESS. In this paper, the power losses of coreless DPMSM/G are separated by the mechanical and rotor eddy current losses in each operating mode. Moreover, the rotor eddy current loss is calculated by the 3-D finite element analysis (FEA) method. The analysis result is validated by separating the power loss as electromagnetic loss and mechanical loss by a spin up/down test.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2217-2220
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• 1997

To achieve the high performance speed control of synchronous permanent magnet motor, the influence of iron loss can not be negleced as the increase of driving frequency with high speed operation. This paper proposes a maximum efficiency control algorithm for permanent magnet synchonous motors by controlling the d-axis component of the armature current at any speed and torque. The objective of the optimum efficiency controller is to seek a combination of d-q axis current components which provide minimum input power (minimum losses) at a certain operating point by adding a small amout of perturbation to the d-axis current reference.