• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1321-1327
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• 2006

This paper presents the calculation of unbalanced magnetic pull (UMP) that causes rotor misalignment in induction motor. The excessive noise and vibration will be occurred by means of rotor misalignment. Angular misalignment of rotor will produce air-gap permeance wave which is function of axial and circumferential coordinate. In this paper, the UMP is calculated using permeance and magneto motive force (MMF) in the case of static and dynamic misalignment. Based on the percentage of misalignment, the result shows that the UMP and magnetic pressure are increased according to the increasing of misalignment. The UMP is occurred not only in It frequency component but also the others.

• Journal of Magnetics
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• v.21 no.3
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• pp.399-404
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• 2016

This paper presents a new permanent magnet (PM) assisted topology for a recently introduced brushless wound rotor synchronous machine (BL-WRSM) [1]. The BL-WRSM had a dual-inverter configuration for generating a composite magneto motive force (MMF) with a fundamental component and a subharmonic component. The subharmonic component of the MMF is used for brushless excitation of the rotor. In this paper, additional PMs were introduced on the rotor of the BL-WRSM, making it a hybrid BL-WRSM. We also discussed the flux weakening operation for the hybrid BL-WRSM. The hybrid BL-WRSM offered advantages for starting the machine and provided better performance under full-load conditions. The finite element method (FEM) was used to analyze the performance of the hybrid BL-WRSM, and we compared its performance with BL-WRSM. Finally, prototypes were built with and without the PM-assistance, and experiments were conducted to demonstrate their performance.

• Journal of Magnetics
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• v.21 no.3
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• pp.405-412
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• 2016

In general, surface mounted PM synchronous motors (SPMSMs) are mainly adopted as a driving motor for high-speed applications, because they have high efficiency and high power density. However, the SPMSMs have some weak points such as the increase of magnetic reluctance and additional losses as a consequence of using a non-magnetic sleeve. Especially, the magneto-motive force (MMF) in the air-gap of the SPMSMs is weakened due to the magnetically increased resistance. For that reason, a large amount of PM is consumed to meet the required MMF. Nevertheless, it cannot help using the sleeve in order to maintain the mechanical integrity of a rotor assembly in high-speed rotation. Thus, in this paper, a multi-layer interior PM synchronous motor (IPMSM) not using the sleeve is presented and designed as an alternative of a SPMSM. Both motors are evaluated by test results based on a variety of characteristics required for an air blower system of a fuel cell electric vehicle.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.601-607
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• 1998

This paper presents the efficient 2-D linear brake analysis model which can compensate the lateral leakage flux by changingng the airgap length and magneto-motive force(MMF). The linkage flux of the 2-D analysis is larger than that of 3-D analysis. This is caused by the assumption in 2-D analysis that geometric and physical values are constant along the perpendicular direction(z) to the analysis region. The equivalent MMF have been calculated from the linkage flux difference between the 2-D and 3-D analyses which are performed at zero velocity. The performances of the linear brake have been analyzed effectively by using the compensated 2-D models without using 3-D FEM.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.907-909
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• 2001

This paper proposes the analysis method for the pole change motor that is a capacitor-run single-phase induction motor. As the Magneto motive force(MMF) at 2-role becomes severe distortion, it is necessary to consider the harmonics for the characteristic analysis of the motor. Therefore, the performance of motor is analyzed by equivalent circuit considering the harmonic components. The validity of the proposed analysis method for the pole change motor is verified through simulations and experimental results.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.910-912
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• 2001

The winding design of a capacitor-run single-phase induction motor for changing two poles(2-/4-pole) is proposed for reducing the harmonics of Magneto Motive Force(MMF) in the airgap at 2-role. To improve motor performance, it is important to analyze exactly the harmonics and design the winding pattern for its harmonics reduction. The winding design method to reduce the harmonics is suggested in this paper and its characteristics are analyzed by using equivalent circuit considering harmonic components. The various performances of the pole change motor with the proposed winding pattern are compared with the experimental results.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.3
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• pp.122-127
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• 2003

This paper presents a new time-stepping 3-D analysis method coupled with an external circuit with motion equation for dynamic transient analysis of induction machines. In this method, the magneto-motive force (MMF) generated by induced current is modeled as a passive source in the magnetic equivalent network. So, by using only scalar potential at each node, the method is able to analyze induction machines with faster computation time and less memory requirement than conventional numerical methods. Also, this method is capable of modeling the movement of the mover without the need for re-meshing and analyzing the time harmonics for dynamic characteristics. From comparisons between the results of the analysis and the experiments, it is verified that the proposed method is capable of estimating the torque, harmonic field, etc. as a function of time with superior accuracy.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.505-506
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• 2015

In this paper, two types of switched reluctance motors (SRMs) with segmental rotors are presented in detail. One is 6/5 segmental rotor type; the other is 12/8 segmental rotor type. Both motors have the same stator, rotor and winding configurations. The stator is constructed with special stator poles in which the exciting and auxiliary poles are designed exclusively. The rotor is constructed from a series of discrete segments, each of which is embedded in the magnetic isolator. The windings are only wound on the exciting poles, and no windings are wound on the auxiliary poles. These structures result in short flux path and high flux-linkage utilization in the proposed motors, which may reduce the magneto motive force (MMF) requirement and increase the electrical utilization of the machine. To verify the proposed two structures, the characteristics of the proposed two types are analyzed and compared with that of conventional 12/8 SRM.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.65-67
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• 2001

In general, the results of finite element method(FEM) on the analysis of the electrical machines has known as high accuracy but required very long time to calculate the field distribution. Magnetic equivalent circuit(MEC) method can be computing times less than the finite element method and also it provides steady state and transient state simulation. In this paper, describes matrix representation of the winding magneto motive force(MMF) and carry out the distributed the airgap magnetic density takes into account the influence on the stator slots.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.990-1001
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• 2015

This paper presents analysis of Switched Reluctance Machine (SRM) using Geometry Based Analytical Model (GBAM), Finite Element Analysis (FEA) and Fourier Series Model (FSM) with curve fitting technique. Further a Transient Analysis (TA) technique is proposed to corroborate the analysis. The main aim of this paper is to give in depth procedure in developing a Geometry Based Analytical Model of Switched Reluctance Machine which is very accurate and simple. The GBAM is developed for the specifications obtained from the manufacturer and magnetizing characteristic of the material used for the construction. Precise values of the parameters like Magneto Motive Force (MMF), flux linkage, inductance and torque are obtained for various rotor positions taking into account the Fringing Effect (FE). The FEA model is developed using MagNet7.1.1 for the same machine geometry used in GBAM and the results are compared with GBAM. Further another analytical model called Fourier Series Model is developed to justify the accuracy of the results obtained by the methods GBAM and FEA model. A prototype of microcontroller based SRM drive system is constructed for validating the analysis and the results are reported.