• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.3
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• pp.137-142
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• 2021

In recent years, permanent magnets such as IPM (Interior Permanent Magnet) motors or SPM (Surface Permanent Magnet) motors that can obtain high efficiency and power density by inserting rare earth permanent magnets into the rotor are used. Research on the used electric motor is being actively conducted. Since it uses a permanent magnet, it has the advantage of high efficiency and high power density compared to reluctance motors and induction motors, but by inserting a permanent magnet into the rotor, it operates at high speeds and decreases reliability due to demagnetization of the permanent magnets, and increases the cost of rare earth metals. In this paper, in accordance with the development of future technology that can replace rare-earth permanent magnet motors and technological preoccupation of rare-earth reduction type motors and de-rare-earth motors, switched reluctance motors that do not require permanent magnets (Switched Reluvtance Motors) Motor, SRM) to drive driving control. Using the 3-phase SRM library provided by the PSIM simulation program, we will study the driving and control system modeling of SRM using the rotor position information sensor.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.3
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• pp.282-288
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• 2012

A special pulsed electromagnetic actuator is presented whose plunger consists of two parts made of carbon steel and permanent magnet, respectively. The actuator exhibits a high holding force and small consumption of energy. The movement of the plunger is controlled by short current pulses. The static characteristics and other operation properties of the device are modeled numerically.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.527-532
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• 2009

Recently, Interior Permanent Magnet Machine(IPM) is widely used for traction motor in the high speed train. Due to the high efficiency and high power density of the IPM, it has lots of heat sources such as iron loss and copper loss. These heat sources can cause the demagnetization of permanent magnet, losses in output power and even irreversible defect of the IPM. To prevent the power loss caused by heat sources, the accurate thermal analysis has to be carried out. For the thermal analysis of the IPM, the thermal network is designed for this traction motor. The thermal analysis has executed at rated speed operation. The result of thermal network analysis can be used for the IPM design process.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.165-170
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• 2010

Recently, Interior Permanent Magnet Machine(IPM) is widely used for traction motor in the high speed train. Higher efficiency and power density are the superb performance of IPM. Due to the high power density, however, it has lots of heat source which are originated from copper losses and core losses. These heat source can cause the permanent demagnetization in magnet and the loss of torque and power. To prevent the undesirable loss in the traction motor, the accurate loss calculation and the thermal analysis should be preceded. Especially, the end-winding area and permanent magnet area should be examined correctly. In this paper, the electromagnetic fields were examined by finite element method to analyze the electromagnetic properties of IPM and thermal analysis are carried out with pre-calculated losses. To validate the analysis result, the experiment set with forced air cooling system is manufactured.

• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1566-1574
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• 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.

• 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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• 2011.07a
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• pp.1007-1008
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• 2011

LSPM(Line Start Permanent Motor)은 기존의 가정용으로 널리 사용되고 있는 단상유도기에 영구 자석을 삽입함으로써 별도의 회로 없이 정상상태에서 동기기로 작용하는 고효율의 전동기이다. 하지만 기동시 높은 전류로 인한 전기자 반작용과 온도 상승으로 인하여 자석의 불가역 감자가 빈번하게 일어나는 문제점을 가지고 있다. 이에 본 논문은 모터 형상에 따른 영구자석의 퍼미언스 계산을 통해 동작점을 산정함으로서 불가역 감자가 발생하지 않는 영구자석의 최적의 사이즈를 선정하는데 목적을 두었다.

• Journal of the Korean Society for Railway
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• v.15 no.4
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• pp.370-375
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• 2012

In order to apply Interior Permanet Magnet Synchronous Motor(IPMSM) to the propulsion system of the railway transit, 110kW class IPMSMs with high-power density are designed as a concentrated winding model and a distributed winding model in this study. The concentrated winding model designed in this study is 6 poles/9 slots and the distributed winding model is 6 poles/36 slots. In general, the eddy current losses in the permanent magnets of IPMSM are caused by the slot harmonics. The thermal demagnetization of the magnet by the eddy current losses at high rotational speed often becomes one of the major problems in the IPMSM with a concentrated windings especially. A design to reduce eddy current losses in permanent magnet design is important in IPMSM for the railway vehicle propulsion system which requires high-speed operation. Therefore, a method to devide the permanent magnet is proposed to reduce the eddy current losses in permanent magnet in this study. Authors analyze the variation characteristics of the eddy current losses generated in permanent magnet of the concentrated winding model by changing the number of the division of the permanent magnets.

• Journal of Electrical Engineering and Technology
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• v.13 no.5
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• pp.1956-1964
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• 2018

Since the stator winding of High-Speed Permanent Magnet Generator (HSPMG) has few winding turns and low inductance value, it is more prone to be influenced by harmonic current. Moreover, the operation efficiency and the torque stability of HSPMG will be greatly influenced by harmonic current. Taking a 117 kW, 60 000 rpm HSPMG as an example, in order to analyze the effects of harmonic current on HSPMG in this paper, the 2-D finite element electromagnetic field model of the generator was established and the correctness of the model was verified by testing the generator prototype. Based on the model, the losses and torque of the generator under different frequency harmonic current were studied. The change rules of the losses and torque were found out. Based on the analysis of the influence of the harmonic phase angle on torque ripple, it is found that the torque ripple could be weakened through changing the harmonic phase angle. Through the analysis of eddy current density in rotor, the change mechanism of the rotor eddy current loss was revealed. These conclusions can contribute to reduce harmonic loss, prevent demagnetization fault and optimize torque ripple of HSPMG used in distributed power supply system.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.942-949
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• 2014

We studied about the rotor design change using a Ferrite ring magnet to reduce material cost in the condition of the same stator core design. However, this design direction has many weak points such as the decrease of BEMF, the low maximum output, the irreversible demagnetization characteristics of a permanent magnet and so on. In order to mitigate such disadvantages, an optimization design of the BLDC motor has been developed by changing each design parameter and by improving the electromagnetic structure. In the proposed water pump SPM BLDC motor using Ferrite magnet, the outer and inner diameter of stator is fixed to the value of the conventional IPM BLDC motor using Nd-Fe-B magnet. The design specification requirements should be satisfied with the same output power and efficiency characteristics in the same dimension. As a result of this study, the design comparison results considering driving performances and material cost are represented. Through the actual experiment with the prototype of the designed motor, the simulations results are verified.