• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.2
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• pp.111-117
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• 2005

Several of the conventional hydraulic systems in an automobile are now being replaced by more reliable and energy efficient electromechanical systems. Developments in the brushless permanent magnet machine and in the power and control electronics are the key factors responsible for this transformation. These applications brought out some performance challenges associated with the brushless machines. This paper will focus on these challenges to be able to use these machines in such applications. In terms of replacing hydraulic systems with electromechanical systems, steering system is leading the way in automobiles. Currently, steering systems using Electro-hydraulically assisted systems and Electrically assisted (Electromechanical) systems are in the market. Though the Electrically assisted power steering has several advantages over other systems, certain performance and cost challenges delayed the penetration of such systems in to the market.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2329-2334
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• 2018

This paper discusses the thermal effect of the number of permanent-magnet (PM) layers in an outer rotor machine. Depending on the number of axial-layer of PM, the operating temperature is compared analytically and experimentally. The electromagnetic analysis is performed using 3-dimensional time varying finite element method to get the heat sources depending on axial-layered PM models. Then thermal analysis is conducted using the lumped-parameter-thermal-network method for each case. Two outer rotor machines, which have the different number of axial-layer of PM, are manufactured and tested to validate the analysis results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.5
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• pp.765-771
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• 2017

This paper presents concurrent design methods of surface permanent magnet synchronous machines for saliency-tracking self-sensing position estimation. Magnetic saliency for the self-sensing is created by stator pole saturation due to the rotor zigzag leakage flux. The power conversion properties such as saliency ratio, torque ripple, and efficiency vary according to motor design. The property change due to design modification is analysed by using finite element analysis, and with the appropriate design modification, proper saliency is created while preserving their power conversion capabilities.

• Journal of Magnetics
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• v.17 no.2
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• pp.100-108
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• 2012

Flux concentrated permanent magnet transverse flux machines, FCPM-TFMs, with segmented stators require multi-turn concentric saddle coils to replace the ring coils, which are normally utilized in conventional layeredphase TFM constructions. In this paper, we investigate the influence of the shape of saddle phase windings and their parameter variations on the output torque productivity. Non-meshed coils evaluated via a finite element method (FEM) to examine the effect of the coil's location within one phase on machine performance. By using meshed coils, the analysis can be extended to inspect the distributions of magnetic field strength as well as current density in the coils. Throughout the study, the influence of design parameters on the output torque for two stator structures, i.e., a laminated and soft magnetic composite (SMC), are evaluated.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.792-793
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• 2015

This paper present a general computation taking into account the slotting effect on the magnetic field due to permanent magnet in surface mounted permanent magnet machine. The analytical method is based on the solution of Laplace's and Poisson's equations (by the separation of variables technique) for each subdomain, i.e., magnets, air gap, and slots. The general solution is obtained using boundary and continuity conditions. The analytical results are in very good agreement with those obtained by the FEA, considering both amplitude and waveform.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.1
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• pp.40-47
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• 2014

Sinusoidal back-EMF waveform of vernier Permanent Magnet (PM) machines is analyzed in this paper. An analytical expression of Electromotive Force (EMF) of electric machines including vernier machines is developed to analyze EMF harmonics, and the effect of vernier PM machine pole ratio, the ratio of number of rotor poles to stator poles, on the EMF waveform. Moreover, this paper represents several Finite Element Analysis (FEA) models to verify the analysis based on the proposed expression, and the effect of tooth width ratio, which is the ratio of tooth width to tooth pitch, on back-EMF of vernier PM machines, and optimal tooth width ratio is obtained and verified by FEA. Finally, this paper makes comparisons between EMF waveform of vernier PM machines and that of traditional PM machines from the point of view of analytical EMF expression.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.763-765
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• 2000

Detent force is produced in a permanent magnet linear machine. It is generally an undesired effect that contributes to the output ripple of machine, vibration and noise. This paper analyzes detent force in a Permanent Magnet Linear Synchronous Motor (PMLSM) by using various detent force minimization techniques. A two-dimensional Finite Element Method(FEM) is used to predict detent forces due to structural factors and non-linearity. And moving node technique for the drawing models is used to reduce modeling time and efforts.

• Journal of Magnetics
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• v.22 no.1
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• pp.78-84
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• 2017

This paper investigates the influence of mechanical energy storage on the interior permanent magnet synchronous machine (IPMSM) when it is operated in the generating mode. An IPMSM with six-poles and nine-slots employing concentrated coil winding type is considered as the analysis model, and a surface-mounted permanent magnet synchronous motor directly connected to a heavy wheel is applied as the mechanical energy storage system by using the moment of inertia. Based on the constructed experimental set-up with manufactured machines and power converters, the generated electrical energy is converted into the mechanical energy, and the electromagnetic filed characteristics of IPMSM are subsequently investigated by applying the measured phase current of IPMSM based on finite element method. Compared to the characteristics in a no-load condition, it is confirmed that the magnetic behavior, radial force, and power loss characteristics are highly influenced by the harmonics of the phase current due to the mechanical energy storage system.

• 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 KIEE Conference
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• summer
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• pp.866-868
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• 2004

The flux-reversal machine(FRM) is a new brushless doubly-salient permanent-magnet machine combining the advantages of the switched-reluctance machine(SRM) and the permanent-magnet machine(PMM) into one machine. FRM has a naturally low inductance, therefore, a low electrical time constant. This feature, combined with its simple construction and low rotor inertia appear to make the FRM attractive as a low-cost high-speed machine. For high-speed applications, two alternative commutation strategies are studied, one using the phase commutation advancing technique and another using the conducting pulse-width control. This paper describes the techniques and reports the corresponding simulated and experimented performance