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자동차 부품용 고속, 고부하 BLDC 모터내의 전자기적 토크 맥동 저감
황상문(S. M. Hwang) 한국자동차공학회 1998 한국 자동차공학회논문집 Vol.6 No.4
For permanent magnet brushiess DC motors used for high speed fuel pumps, torque ripple is an important origin of vibration, acoustic noise and speed fluctuation. In this paper, the output torque profile of a PM motor with one phase energized is decomposed into the commutation torque, the reluctance torque and the armature reaction torque according to their source origins. It verifies that the output torque profile is qualitatively equivalent to the BEMF profile for low reluctance motors. This paper discusses the effect of magnet pole shaping and magnet arc length on the output torque and torque ripple. A magnet edge shaping is proposed to design a trapezoidal BEMF motor without torque ripple, with minimal sacrifice of the maximum output torque.
전기 조향 장치용 직류 전동기에서의 코깅 토크 저감을 위한 설계 기술 개발
황상문(Sangmoon Hwang) 한국자동차공학회 1996 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1996 No.11_2
Cogging torque is often a principal source of vibration and control difficulty in permanent magnet motors, especially at low speeds and loads. For example, reduction of cogging torque is a important specification for DC motors used for electric power steering. This paper examines two motor design techniques, stator tooth notching and rotor pole skewing with magnet pole shaping, for reduction of cogging torque, and the effect of each method on the output torque. Prediction of results was performed by finite element analysis of the airgap flux, and the use of the Maxwell stress method and Fourier decomposition to calculate the periodic cogging torque. The analyses show that the cogging torque can be nearly elimimated by the suggested designs, with minimal sacrifice of output torque.
자동차 부품용 BLDC 모터 내의 코깅 토크 저감을 위한 설계 변수의 민감도 해석
황상문(S. M. Hwang) 한국자동차공학회 1998 한국 자동차공학회논문집 Vol.6 No.2
For motor operation at low speeds and loads, torque pulsation by the cogging torque is often a source of vibration and control difficulty. In this paper, the magnetic field of a motor is calculated by finite element method. The periodic cogging torque is determined using Maxwell stress method and time stepping method, and then decomposed using Fourier series expansion. The purpose of this paper is to characterize design parameters on the cogging torque and to design a permanent magnet motor with a cogging torque less vulnerable to vibration, without sacrificing the motor performance. The design parameters include stator slot width, permanent magnet slot width, airgap length and magnetization direction. A new design with a less populated frequency spectrum of the cogging torque is proposed after characterizing individual effect of design parameters. Magnet pole edge shaping, by gradually increasing the thickness of the permanent magnet at edges, yields a smooth shape for the cogging torque with reduced higher harmonics.
이동통신 단말기용 통합 영구 자석 형태의 마이크로스피커 개발
황상문(Hwang, Sang-Moon),이홍주(Lee, Hong-Joo),권중학(Kwon, Joong-Hak),황건용(Hwang, Gun-Yong),양용창(Yang, Yong-Chang) 한국소음진동공학회 2006 한국소음진동공학회 논문집 Vol.16 No.2
In mobile phones of multimedia era, microspeakers of high qualify sound are essential parts to generate human voice in speaker phone and MP3 song player. In this paper, two types of microspeakers, outer permanent magnet (PM) and combined PM type, are analyzed using electromagnetic, mechanical and their coupling analysis. For performance comparison, voice coil diameter is chosen as a design parameter to change excitation position and magnet volume for both types. For combined PM type, sound pressure level (SPL) is improved due to increased PM volume compared to outer PM type. Also, with the decreased voice coil diameter for combined PM type, the 1st resonant mode of the diaphragm is more efficiently excited due to concentrative excitation, resulting in lower and broader frequency range. Therefore, it can be said that the combined PM type microspeakers are more advantageous for high performance microspeaker which are essential for multimedia era.
Development of hybrid system with fuel cell and lithium secondary battery
황상문(Hwang, Sangmoon),정은미(Jung, Eunmi),손동언(Son, Dongun),심태희(Shim, Taehee),송하영(Song, Hayoung) 한국신재생에너지학회 2010 한국신재생에너지학회 학술대회논문집 Vol.2010 No.06
Therefore, with this development assignment we'd like to develop the hybrid system combining 800W DMFC (Direct Methanol Fuel Cell) and 1.6kW of Lithium secondary battery pack which can be applied to the most common small cart. a scooter, to secure the development capability of hundreds of Watts DMFC, the high-capacity Lithium secondary battery pack, the technology of BMS (Battery Management System) and the development technology of hybrid system. DMFC, in fact, has lower energy efficiency than PEMFC (Polymer Electrolyte Membrane Fuel Cell); however, it has several advantages in terms of fuel storage and use. It is pretty easy to be stored and used without any additional colling and heating devices because of its insensitive liquid methanol to temperature. In conclusion, DMFC system is the most suitable device for small mobile vehicles.