• Proceedings of the KIEE Conference
• /
• 2001.04a
• /
• pp.33-36
• /
• 2001

Torque ripple control of brush less DC motor has been the main issue of the servo drive systems in which the speed fluctuation, vibration and acoustic noise should be minimized. Most methods for suppressing the torque ripples require Fourier series analysis and either the iterative or least mean square minimization. In this paper, the novel approach to achieve the ripple-tree torque control with maximum efficiency based on the d-q-0 reference frame is presented. The proposed method optimize the reference phase current waveforms including even the case of 3 phase unbalanced condition, and the motor winding currents are controlled to follow up the optimized current waveforms by delta modulation technique. As a result, the proposed approach provides a simple and clear way to obtain the optimal motor excitation currents. The validity and practical applications of the proposed control scheme are verified through the simulations and experimental results.

• Proceedings of the KIEE Conference
• /
• 2001.04a
• /
• pp.30-32
• /
• 2001

Switched reluctance motors have the advantage a high torque/weight ratio, as the large reluctance torque is made by salient poles of both start and rotor, and a high reliability. On the other hand, the switched reluctance motors have the disadvantage of a large ripple torque which is made by salient poles. So the application for the industrial fields have been limited to special cases. Geometric significant parameters are ${\beta}_r$ and ${\beta}_s$ respectively the rotor and stator pole arc while the significant electric parameters are the angles where the drive switches are turned on and off. It can be simulated that ${\beta}_r$ and ${\beta}_s$ must be chosen in a particular region of the plane (${\beta}_r,\;{\beta}_s$) called the feasible triangle. The aim of this paper is to simulate the minimum of the torque ripple by using finite element method and to determine the best choice of the rotor and stator pole arc.

• Proceedings of the KIEE Conference
• /
• 2006.07b
• /
• pp.803-804
• /
• 2006

우리는 이전 논문을 통해 Air blower용 모터에서 널리 사용되고 있는 단상 유도기를 기존의 분포 권선 방식에서 벗어나 집중 권선 방식을 사용하여 설계한 결과 생산 공정의 단계를 줄이고 많은 생산 비용을 줄일 수 있었다. 또한 집중 권선형에서 발생할 수 있는 고조파 문제를 로터의 skew와 overlap 권선 방식을 이용하여 해결 할 수 있음을 증명하였다. 그러나 이러한 이점에도 불구하고 시제품의 특성을 측정한 결과 집중 권선형 모터의 자계 불균형 때문에 기존 분포권 모터에 비해 소음과 진동 특성이 좋지 않은 결과를 보였다. 이에 본 논문에서는 소음과 진동 특성을 고려하여 기존의 기동 및 정격 토크 특성을 유지하면서 토크 리플을 저감할 수 있는 방법을 로터의 Skew 각도 영향, 권선 사양 및 스테이터 및 로터 형상 등을 고려하여 새롭게 설계하였고 그 결과를 제시하였다.

• Journal of the Korean Society for Railway
• /
• v.19 no.5
• /
• pp.600-608
• /
• 2016

This paper will describe the optimal design of an induction motor for the propulsion of an electric railway. First, the design requirements are satisfied through the basic model, which is designed in a design process using the equivalent circuit. Then, Rotor slot and Airgap are determined by analysis and comparison of torque, torque ripple, efficiency, and power factor. In addition, Rotor slot shape is optimized by using the response surface method. Finally, through the results of equivalent circuit and FEA, the final model is found to satisfy the design requirements; its efficiency was far higher than that of the basic model.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.20 no.5
• /
• pp.429-436
• /
• 2015

Torque ripples generate mechanical vibration at low speed and acoustic noise at high speed. The back emf harmonics of a PM synchronous motor is one of the main sources of torque ripples. To reduce torque ripples resulting from back emf harmonics, dq-axis harmonic currents that reduce the torque ripples are generally compensated to the current controller. Harmonic current compensation is effective at low speed, but it is not applicable at high speed because of the limited bandwidth of the current controller. In this study, dq-axis harmonic voltage compensation that can reduce torque ripples at high speed is proposed. The dq-axis harmonic voltages are calculated from the motor speed and the dq-axis harmonic currents. The effectiveness of the proposed method in reducing torque ripple is verified by a simulation and experiments.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.20 no.8
• /
• pp.54-62
• /
• 2006

Voltage unbalance will be generated by the load unbalance operation such as combination operation of single & three phase load and current unbalance will be more severe by the deteriorated voltage quality. Under the these unbalance conditions, all power electronic converters used in different types of electronic systems can increase harmonic disturbances by injecting harmonic currents directly into the feeder grid of three phase 4-wire. Harmonic current may cause torque to decrease. it may also overheat or become noisy and torque oscillation in the rotor can lead to mechanical resonance and vibration. This paper presents a scheme on the characteristics of induction motor under the combination of linear & non-linear loads at the three phase 4-wire power distribution system by the unbalance and harmonic components. It was able to confirm that the number of torque pulsation decreased and torque ripple values increased by the harmonics that reduction was difficult by five harmonics filters at additional driving time of single-phase non-linear load.

• Proceedings of the KIEE Conference
• /
• 2006.04b
• /
• pp.137-139
• /
• 2006

단 1차형 영구자석 선형 동기 전통기(PMLSM)는 디텐트력과 단부력에 의한 큰 토크 리플을 갖는 문제점이 있다. 본 논문에서는 영구자석 선형 통기 전동기의 디텐트력을 줄이기 위해 영구자석의 극수와 전기자의 슬롯수의 비를 변경한 새로운 구조의 단 1차형 영구자석 선형 동기 전동기를 제안하였으며, 단부력을 줄이기 위하며 고정자의 길이 조정 및 챔퍼링을 통하여 영구자석 선형 동기 전동기를 설계하였다.

• Proceedings of the KIEE Conference
• /
• 2006.04b
• /
• pp.91-94
• /
• 2006

Miniature BLDC is widely used in industrial applications and especially medical appliances because of there character that high driving efficiency and high torque characteristic. However torque ripple of a high speed miniature BLDC is serous in switching period cue to the very electrical time constant. This paper present instant voltage and current control for torque ripple reduction of a high speed miniature BLDC. Computer simulation and experiment test for 40,000 rpm miniature BLDC show the verification of the proposed control method.

• Proceedings of the KIEE Conference
• /
• 2004.11c
• /
• pp.373-375
• /
• 2004

The SRM is more robust and lower cost than other type motors. The inverter for SRM cannot have shoot through fault, since a phase winding of SRM is independent of other phase windings. The SRM has high starting torque and high power density. But it has torque ripples due to nonlinear magnetic characteristics. Therefore, SRM has highly non-linear torque producing characteristics. Because fuzzy logic is a flexible and general-purposed method for implementing non-linear dynamic functions, it is effective for the control of high current SRM. We design the fuzzy controller and demonstrate the fuzzy control system by MATLAB.

• Proceedings of the KIPE Conference
• /
• 2003.07a
• /
• pp.472-476
• /
• 2003

In this paper, a new current control algorithm is proposed for four-switch three-phase brushless DC(BLU) motor drives, which are suitable for low cost applications. A current reference generation scheme is developed and Implemented to obtain high performance characteristics in the four-switch system, such as small torque ripple and fast dynamic speed/torque response. Moreover, the proposed scheme can successful1y eliminate the torque ripple during commutations, so that it can be expected that the four-switch system can be much more practically applied for the industrial application areas.