• 한국정밀공학회지
• /
• 제16권7호
• /
• pp.15-23
• /
• 1999

With a remarkable expansion of communication industry, a pager or a cellular phone becomes a necessary communication device in modern society. However, a paging signal by a buzzer is often acted as an unpleasant noise in some places, thus necessitating a paging signal by a vibration motor. In this paper, a simpler type of a vibration motor, a coreless permanent magnet(PM) DC motor, is considered to substitute for the conventional vibration motors. Using an analytical method, electromagnetic field and operating torque were calculated for the given inner and outer PM type motors, and the results were confirmed by FEM analysis. As design parameters, number of PM poles, PM radial thickness, coil arc angle and number of winding stacks were chosen for sensitivity analysis. It shows that coil arc angle is the most important design parameter to increase the motor performance, without giving an adverse effect on motor weight, size and manufacturing cost. Based on the analysis of the outer PM type motor, an outer square PM type motor is proposed as the final design. Compared to the outer PM type, outer square type provides more flexibility to attach to the small size cellular phones. With the optimum design of square outer PM DC motor, it can successfully substitute the conventional types with less expensive manufacturing cost. better performance and smaller necessary space.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
• /
• 제5B권2호
• /
• pp.137-141
• /
• 2005

A transverse flux, PM-exited linear motor (TFM-LM) with inner mover was designed and built. Its output power density is higher and its weight is lower than those of the conventional PM exited linear synchronous motors (PM LSM). To obtain the maximum thrust force under the given volume, the thrust force density with respect to the ratio of the slot width and the length of pole pitch is analyzed by the 3-dimension finite element method (FEM). Finally, calculated static thrust forces was compared with the experimental values. The calculated and measured performance of the transverse flux, PM-exited linear motor with inner mover revealed great potential for system improvements by reducing the mass of the linear motor. For examples, when this motor was applied to a ropeless elevator, it was possible to increase the power density by more than 400% over the conventional PM-LSM. The results of this study recommend this type of motor for the ropeless elevator or gearless direct linear driving system.

• 조명전기설비학회논문지
• /
• 제27권12호
• /
• pp.114-124
• /
• 2013

Recently, the real time simulator to develop the inverter drive board and motor control algorithm for high power induction motor and PM synchronous motor is required. In this paper, the real time simulator based on the voltage control for a PM synchronous motor is proposed. The resistor, inductor, and the induced voltage for the modeling of a PM synchronous motor is implemented by the power converter including the LCL filter and the PWM rectifier. The induced voltage of a PM synchronous motor is simulated by the capacitor voltage of the LCL filter, which is controlled by PI voltage controller and the deadbeat current controller. The operation and the simulated characteristics of the proposed real time simulator for a PM synchronous motor is verified by the simulation.

• Clinical and Experimental Pediatrics
• /
• 제49권4호
• /
• pp.375-380
• /
• 2006

목 적 : 엎어 재우기, 똑바로 누워 재우기, 옆으로 재우기 등 수면 자세에 따라서 조대운동발달과 미세운동발달이 차이가 나는지 살펴보기 위해서 연구를 시작하였다. 방 법 : 2003월 12월부터 2005년 9월까지 1년 9개월 동안, 전주예수병원 소아과를 방문하는 3개월부터 16개월 사이의 소아 800명을 대상으로 운동발달검사, 수면 자세, 몸무게를 조사하여 연구하였다. 결 과 : 똑바로 누워 재우기가 79.3%, 엎어 재우기가 10.0%, 옆으로 재우기가 10.7%로, 똑바로 누워 재우기가 가장 많았다. 남아와 여아의 조대운동발달 지수는 각각 $109.5{\pm}16.3$, $108.1{\pm}17.3$이었으며, 미세운동발달 지수는 각각 $102.3{\pm}17.1$, $100.7{\pm}16.9$로 성별에 따른 발달의 차이는 없었다. 똑바로 누워 재우기, 엎어 재우기, 옆으로 재우기에 따른 조대운동발달 지수는 5개월에 $98.2{\pm}16.8$, $126.2{\pm}10.9$, $117.2{\pm}6.6$, 6개월에 $101.2{\pm}13.0$, $115.2{\pm}18.0$, $95.7{\pm}20.2$로 각각 엎어 재우기에서 의의 있게 높았다. 7개월에서 16개월까지는 차이가 없었다. 똑바로 누워 재우기, 엎어 재우기, 옆으로 재우기에 따른 미세운동발달 지수는 차이가 없었다. 연령별 평균 미만의 몸무게 군과 연령별 평균 이상의 몸무게 군에서, 조대운동발달 지수는 각각 $106.3{\pm}16.3$, $109.9{\pm}16.8$이고, 미세운동발달 지수는 각각 $99.4{\pm}16.2$, $102.5{\pm}17.2$로 연령별 평균 이상의 몸무게 군에서 조대운동발달 지수와 운동발달 지수가 의의 있게 높았다. 결 론 : 엎어 재웠을 경우 5개월과 6개월에서 조대운동발달 지수가 높았으나, 7개월부터는 차이가 없었다. 따라서 운동발달을 빠르게 하기 위해서 엎어 재우는 것은 의미가 없는 것으로 판단된다.

• 조명전기설비학회논문지
• /
• 제27권12호
• /
• pp.125-132
• /
• 2013

This paper has done a three-dimensional FEM analysis of the PM claw pole stepping motor. As magnetization happens in the z-axis, which does not have a constant value, three-dimensional FEM analysis is necessary for characteristic analysis of PM claw pole stepping motors. Because it is a type of permanent magnet motor, the PM claw pole stepping motor naturally has a detent torque. This torque is known to show negative effects on motor performance. To improve motor performance, reducing the detent torque is very important during the motor design. This paper applied DOE for optimization of stator pole design of the motor. Also, we compared motor performance by applying a different type of rotor shape, dividing the permanent magnet. To verify the simulation results, an experiment was done.

• 전기학회논문지
• /
• 제62권4호
• /
• pp.495-501
• /
• 2013

In the present study, a BLDC motor for a pump in which a neodymium PM is replaced with a Ferrite PM has been developed in preparation for the cost increase and to ensure the stability of the resource supply. One of the currently used motors for pumps is a BLDC motor having an interior PM wherein a rare-earth PM is adopted. However, a BLDC motor for a pump is designed to have large airgap because of the use of a waterproof insulator according to its structural characteristics, and therefore, a SPM structure is suitable. Hence, an SPM BLDC motor in which a Ferrite PM is used is designed. Nevertheless, the use of Ferrite instead of rare-earth materials causes a deterioration in the performance of the electric motor, such as a decrease in the BEMF and the maximum power of the motor and the irreversible demagnetization of the PM. In order to mitigate such disadvantages, an optimized design of the BLDC motor is developed by changing each design parameter and by improving the electromagnetism structure.

• 전기학회논문지
• /
• 제57권12호
• /
• pp.2208-2212
• /
• 2008

This paper deals with the cost reduction design of a single-phase line-start permanent magnet(LSPM) motor. Due to high cost of the permanent magnet(PM), cost reduction can be effectively achieved by reducing PM volume. Therefore, motor characteristics according to the PM volume are calculated by using d-q axis equivalent circuit analysis, and the characteristic map is made. In the characteristic map, maximum torque and efficiency are shown according to motor parameters such as back electromotive force(back emf) and inductances; back emf represents the PM volume. Minimum back emf and inductances satisfying output performance are determined in the characteristic map. Then, motor geometry based on the prototype motor is optimized to get the determined parameters using response surface methodology(RSM) and finite element method(FEM). Through the presented cost reduction design, total PM volume is reduced to 32% of prototype model.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2009년도 제40회 하계학술대회
• /
• pp.857_858
• /
• 2009

On account of small size and light weight, a high-speed machine is regarded as a key technology for many future applications of drive systems. In high-speed applications, permanent magnet (PM) synchronous motors have a number of merits such as high efficiency and high power density. Accordingly, they are suitable for driving the air-blower of a fuel cell electric vehicle (FCEV) where space and energy savings are critical. Particularly, a surface-mounted PM motor of them is mainly used as a high-speed machine. However, the motor has a fatal flaw owing to a retaining can to maintain the mechanical integrity of a rotor assembly. The can results in the increase of magnetic air-gap length in the surface-mounted PM motor. Thus, in this paper, an interior PM motor is designed in order to drive the air-blower of FCEV instead of the surface-mounted PM motor, and the experimental results of two models are compared to verify the capability of the interior PM motor for a high-speed machine.

• Journal of Magnetics
• /
• 제15권2호
• /
• pp.78-84
• /
• 2010

A 3-D.O.F. spherical PM motor has 3 degrees of freedom in its motion by tilting and rotating of a shaft, which can be applied in a range of fields. The back-EMF is proportional to the field flux and angular velocity. The back-EMF constant in conventional rotating machine has a uniform value. However, in a spherical PM motor, the back-EMF constant of the coils varies according to the tilting conditions regardless of whether the angular speed is constant. Consideration of the back-EMF constant is useful for designing 3-D.O.F. spherical PM motors. In this study, the back-EMF constant of the spherical PM motor was considered carefully.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
• /
• pp.470-475
• /
• 1998

A robust control technique is presented for a high performance control of a permanent-magnet(PM) synchronous motor. In order to deal with the internal and external disturbances of a PM synchronous motor drive system, a new feedback control structure is proposed. Since the dynamic behavior of the PM synchronous motor drive system is mainly concerned with the difference between the electro-magnetically developed torque and the load torque which generally referred to as an accelerating torque, the estimation and control techniques of this torque are introduced. The simulations and experiments are carried out for the DSP-based PM synchronous motor drive system and the results well demonstrate the effectiveness of the proposed control technique.