• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.6
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• pp.551-557
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• 2006

The electrical frequency synchronized periodic torque ripple exits in the AC motor. There are various sources of torque ripple in AC motor such as current measurement error, dead time, etc. This paper proposes a compensation algorithm which suppresses undesired side effect known as the periodic torque ripple of AC motor. The torque ripple compensation classified as the speed ripple detector and torque ripple compensator. This paper proves a speed ripple minimization at steady state by analysis of torque ripple compensator. A new speed ripple detector improves the performance of torque ripple compensation algorithm. The simulation and experimental results show that the compensation algorithm is effective and the torque ripple compensation method improves the performance of speed ripple detector by eliminating torque ripples effectively.

• Journal of Electrical Engineering and Technology
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• v.7 no.3
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• pp.349-357
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• 2012

This paper presents a hybrid motor prototype convenient to modify the magnet and reluctance torques. The rotor of the prototype consists of magnet and reluctance parts, so the generated torque includes both magnet and reluctance torques. A considerable feature of the motor is that the ratio of the magnet and reluctance parts can be modified on the rotor and the rotor hybridization ratio can be varied. Another important point is the mechanical angle between the parts changed by means of the suitable construction of the parts on the rotor shaft. Finite element (FE) analysis was carried out for the proposed motor and static torque measurements were realized. The FE results were compared with the experimental results. Average torque and maximum torque values were obtained and three dimensional 3-D graphs were formed by using the experimental data. It is possible to make different combinations by changing the parts and the angle between the parts due to the proposed motor. So the magnet and reluctance torques are modified and different combinations give different torque behavior.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.3
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• pp.123-127
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• 2004

Mode conversion type ultrasonic rotary motor using bolt tightened Langevin type vibrator was studied. Driving frequency of the motor, displacements and elliptical trajectories at tip of the coupler were simulated by finite element analysis program (ANSYS). Speed and torque of the fabricated motor were measured as functions of input voltage and load. As results, from FEA the driving frequency of 40.8[kHz] and useful elliptical trajectories were found. Fabricated motor rotated clockwise at frequency of 38.2[kHz]. Speed and torque of the motor were increased when the input voltage was increased. Maximum speed, torque and efficiency were 75[rpm], 0.14[Nm] and 6.28[％], respectively.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.1
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• pp.61-65
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• 2012

Some works about the current sensorless control of a synchronous reluctance motor have been presented. However, there is no analysis about the performance and the detuning effect of the current sensorless control. This paper presents the problems and the detuning effect of the current sensorless control of a synchronous reluctance motor by simulation results. In addition, torque limiter is proposed to limit the torque current within the torque limit.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.4
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• pp.188-194
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• 2013

Hydrostatic pumps and motors occupy an important position in hydraulic system. There are a lot of researches on characteristics of hydraulic pumps, but not hydraulic motors. So in order to know the characteristics of hydraulic motors we had this research. The purpose of this study is to derive and analyze the theoretical calculation of hydraulic axial piston motor torque and torque ripples. Then, analyzed the differences between torque ripples with dead place and without dead place on the valve plate, and modeling a hydraulic motor with AMESim software. Finally, theoretical calculation of hydraulic motor torque ripples was verified from the viewpoint of simulation.

• Journal of Mechanical Science and Technology
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• v.15 no.7
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• pp.831-838
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• 2001

Torque ripple control of brushless DC motor has long been the main issue of the servo drive systems in which the speed fluctuation, vibration and acoustic noise need to be minimized. The vast majority of the methods for suppressing the torque ripple require the Fourier series analysis and either the iterative or least mean square minimization. In this paper, a novel approach based on the d-q-0 reference frame that achieves ripple-free torque control with maximum efficiency is presented. The proposed method optimizes the reference phase current waveforms including even the case of 3-phase unbalanced condition, and the motor winding currents are controlled to track the optimized current waveforms by the delta modulation technique. As a results, the proposed approach provides a simple and yet effectine means for obtaining the optimal motor excitation currents. The validity and applicability of the proposed control scheme are verified through simulations and experimental investigations.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.397-399
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• 1999

This paper deals with the torque characteristics of a AFPM motor excited by permanent magnets. According to relative angle difference of two rotor, torque characteristics are studied. According to varied angle of two rotor, torque ripple and, total torque of AFPM motor is different. For minimum torque ripple, angle of two rotor of AFPM motor are investigated. For this study, we used to Maxwell EM 3D program. A prototype AFPM motor have been assembled and driving power supply are made. Characteristics of magnetical and electrical characteristic are investigated.

• Journal of Magnetics
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• v.21 no.4
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• pp.570-576
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• 2016

The shape optimization of the stator and the rotor is important for electrical motor design. Among many motor design parameters, the stator tooth and yoke width are a few of the determinants of noload back-EMF and load torque. In this study, we proposed an equivalent magnetic circuit of motor stator for efficient stator tooth and yoke width shape optimization. Using the proposed equivalent magnetic circuit, we found the optimal tooth and yoke width for minimal magnetic resistance. To verify if load torque is truly maximized for the optimal tooth and yoke width indicated by the proposed method, we performed finite element analysis (FEA) to calculate load torque for different tooth and yoke widths. From the study, we confirmed reliability and usability of the proposed equivalent magnetic circuit.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.9
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• pp.437-442
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• 2006

Cogging torque, the primary ripple component in the torque generated by permanent magnet (PM) motors, is due to the slotting on the stator or rotor. This article shows the reduction of cogging torque in a novel axial flux permanent magnet (AFPM) motor through the various design schemes. 3D finite element method is used for the exact magnetic field analysis. The effects of slot shapes and skewing of slot on the cogging torque and the average torque have been investigated in detail.

• Proceedings of the KIEE Conference
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• summer
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• pp.1022-1024
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• 2004

This paper presents a design and characteristics analysis of an SRM drive for EPS application. A rack mounted EPS system is considered in this paper. In the unrestricted design conditions, motor parameters are determined for sufficient torque and speed with some restrictions. For the smooth torque generation and simple circuit of power system, 12/8 motor drive is considered. With FEM and magnetic circuit analysis, redesigned motor is simulated to meet the requirement of specifications. Effectiveness of the suggested SRM drive for EPS application is verified by redesigned motor drive tests.