• Proceedings of the KIPE Conference
• /
• 2016.07a
• /
• pp.109-110
• /
• 2016

본 논문에서는 현재 운행되고 있는 선형 유도전동기의 슬립주파수 고정 방식이 아닌 선형 유도전동기를 이용한 자기부상열차의 슬립주파수와 수직력 및 추진력과의 관계를 이용, 열차의 가감속시 운행패턴에 따라 운행 중 슬립주파수가 가변할 수 있는 슬립주파수 가변패턴을 형성, 선형유도전동기 자기부상시스템에서의 에너지 효율향상 가능성을 검증하였다. 슬립주파수와 수직력, 추진력과의 관계를 이용 슬립주파수 일정 실효치전류제어 알고리즘과 슬립주파수 일정 벡터제어 알고리즘을 사용하여 운전조건과 슬립주파수를 변경하며 운전조건에 따른 가장 효율적인 슬립주파수의 패턴을 형성하였다. 이 후 모의시험과 실차를 이용한 실험을 통해 알고리즘에 대한 정당성과 실제 효율의 증가를 통해 타당성을 검증하였다. 앞선 두 가지 알고리즘을 통해 열차부상에 영향을 미치지 않는 범위의 수직력을 가지는 범위내에서 슬립주파수를 가변 운전 조건에 따른 최적의 슬립주파수에 대한 정보를 기반으로 운행 중 가변하는 슬립주파수를 자동열차운전(ATO)시스템에 적용 모의실험을 통해 그 적용가능성과 효율을 검증하였다.

• Proceedings of the KIEE Conference
• /
• 1996.07a
• /
• pp.591-593
• /
• 1996

In order to implement the direct vector control type sensorless vector control, the rotor flux and the angular speed of the rotor can only be estimated through the measurement of the stationary voltage and current states. To estimate the rotor flux, the use of the rotor flux observer(RFO) has been proposed. It is known that the RFO is relatively insensitive to parameter variations. Using the rotor flux value obtained from the RFO, the rotor flux vector can be estimated. The angular speed of the rotor is estimated by the difference between the synchronous angular speed and the slip angular speed, both of which are derived from the rotor flux vector. However unwanted high order frequency waves become incorporated into the synchronous angular speed during calculations. Thus we propose the use of digital filters that will eliminate these high frequency waves. We have demonstrated through computer simulations that the use of filters results in stable system activity over a wide speed range and good response to load variations.

• Proceedings of the KIEE Conference
• /
• 2003.10b
• /
• pp.216-219
• /
• 2003

The resonant inverter is widely used for induction heating, electronic ballast and supersonic motor driving circuit. In the meantime, control techniques of PWM, PFM etc.. are mainly applied to control the output power of the resonant inverter. But, in the case of using the half bridge resonant inverter, it is difficult to control the output power by PWM, because its main circuit does not provide the load free-wheeling mode. Therefore, PAM or PFM was usually applied to control output power of half bridge resonant inverter. However, PAM needs a variable DC voltage source, which makes the system structure more complex. On the other hand, in case of PFM, efficiency is declined by operation with poor power factor. This paper Proposed the novel half bridge resonant inverter which can provide the load free-wheeling mode. Also its analysis results for PWM operation with unity fundamental power factor are Presented and compared with other resonant inverters using PWM and PFM.

• Proceedings of the KIPE Conference
• /
• 2001.10a
• /
• pp.160-168
• /
• 2001

The RPWM (Random· Pulse Width Modulation) is a switching technique to spread the voltage and current harmonics over a wide frequency area. By using randomly changing switching frequency of the inverter, the power spectrum of the electromagnetic acoustic noise can be spread to the wide-band area. The wide­band noise is much more comfortable and less annoying than the narrow-band one. So, the RPWM has been attracting interest as an excellent method for the reduction of acoustic noise on the inverter drive system. In this paper a new RPPWM (Random Position Space Vector PWM) is proposed and implemented. Each of three phase pulses is located randomly in each switching interval. Along with the randomization of PWM pulses, the space vector modulation is also executed in the C167 micro-controller. The experimental results show that the voltage and current harmonics are spread to a wide band area and that the audible switching noise is reduced by the proposed RPPWM method.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2005.11a
• /
• pp.106-109
• /
• 2005

산업화와 더불어 자동화의 요구에 따라 여러 분야에서 유도전동기의 응용 사례가 늘어나고 있다. 본 연구는 인버터단의 전류센서에서 실시간 얻어진 전류신호로 부터 대표적인 전기, 기계적인 4가지 고장(Bearing Fault, Broken Rotor bar, Misalignment, Unbalance)을 검출하여 예기치 못한 고장에 대비할 수 있는 실시간 진단 알고리듬을 제시한다. 실시간 진단의 핵심요소인 동기화 방법으로서 Hilbert Transform을 응용하였다. 총 40세트의 정상 모터 데이터를 임의로 선택하여 두 데이터의 차를 이용하여 0에 근사한 정상 모터 뎀플릿 값을 설정하였다. 이를 이용하여 진단 대상 전동기의 고장 유무를 미리 판단하게 된다. 만약 기준치 이상의 오차가 나타나게 되면, 이와 비교하기 위한 미리 수집된 각4가지 고장 전동기의 미소신호 템플릿 데이터와의 유사성을 비교하여 고장의 종류를 표시하며, 고장의 종류가 진단되지 않은 대상은 고장 유무만 표시된다.

• Journal of the Korean Society for Precision Engineering
• /
• v.23 no.3 s.180
• /
• pp.76-85
• /
• 2006

In the manufacture of liquid crystal display devices, there is a strong demand for contactless glass panel handling devices that can manipulate a glass panel without contaminating or damaging it. To fulfill this requirement, an electrostatic transportation device for glass panels is proposed. This device can directly drive a glass panel and simultaneously provide contactless suspension by electrostatic forces. To accomplish these two functions, a feedback control strategy and the operational principle of an electrostatic induction motor are utilized. The stator possesses electrodes which exert electrostatic farces on the glass panel and are divided into a part responsible for suspension and one for transportation. To accomplish dynamic stability and a relatively fast suspension initiation time, the structure of the electrode for suspension possesses many boundaries over which potential differences are formed. In this paper, an electrode pattern suitable for the suspension of glass panels is described, followed by the structure of the transportation device and its operational principle. Experimental results show that the glass panel has been transported with a speed of approximately 25.6 mm/s while being suspended stably at a gap length of 0.3 mm.

• Proceedings of the KIEE Conference
• /
• 2006.10d
• /
• pp.101-103
• /
• 2006

외전형 유도전동기 모터는 내전형에 비해 소형화 및 경량화 시킬 수 있는 장점이 있다. 하지만 회전자와 고정자간의 공극사이에 이심률이 있을 때, 불균형 모멘트로 인한 토크 리플이 내 전형보다 더 크게 일어나는 단점이 있다. 이러한 토크리플은 모터의 정속적인 운전을 방해시킬 뿐만 아니라 불규칙한 출력토크로 인한 작동상의 오류를 초래한다. 본 논문에서는 의전형 모터에서 이심률에 따른 불균형력이 최소화 될 수 있는 슬롯 형태에 대해서 연구하기 위해, 전폐형, 반폐형, 개구형태의 3가지 슬롯 형태에 대한 특성을 비교 하였다. 개구형의 경우 슬롯 누설 리액턴스가 낮아져 토크 형성율이 매우 높아 높은 토크를 발생시킬 것을 예상 하였지만, 토크 리플에 따른 출력 감소로 오히려 출력토크가 감소할 뿐만 아니라 이심률 증가에 따른 불균형력 또한 매우 컸다. 이에 비해 전폐형태의 슬롯은 누설리엑턴스의 영향으로 토크 형성 자체는 10% 정도 저감 되었으나, 이심률 증가에 따른 분균형력이 가장 적어 의전형 모터에 가장 적함한 형태임을 알 수 있었다.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.13 no.2
• /
• pp.135-144
• /
• 2008

A bootstrap circuit is widely used for the floating gate power supply of Intelligent power module (IPM). A bootstrap circuit is simple and inexpensive. However, the duty cycle and on-time are limited by the requirement to refresh the charge in the bootstrap capacitor. And the value of the bootstrap capacitor should be increased as the switching frequency decreases. A charge pump circuit can be used to overcome the problems. This paper deals with an analysis and design of a charge pump circuit for the floating gate power supply of an IPM. The simulation and experiment are carried out for an induction motor drive system. The results well verifies the validity of the proposed circuit and design method.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.6 no.6
• /
• pp.525-537
• /
• 2001

In this paper a new space vector RPPWM(Random Position PWM) is proposed. In the propsed RPPWM each of three phase pulses is located randomly in each switching interval. Based on the Space vector modulation technique the duty ratio of the pulses is calculated Along with the randomization of the PWM pulses. we can obtain the effects of spread spectra of votlage, current as in the case of randomly changed switching frequency, To verify the validity of the proposed RPPWM simulation study was tried using Matlab/Simulink The main model described in Simulink block diagrams includes the space vector modulation block pulse position randomization block inverter block 3 phase induction motor block and so on By the simulation study, the harmonics of the output voltage and the current of inverter are predicted in different PWM methods- SVPWM, LLPWM proposed RPPWM.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.12
• /
• pp.3581-3586
• /
• 2009

This paper designed a robust control of an induction motor using a disturbance cancellation observer of a feedforward control. The speed response of conventional PI controller characteristic is affected by variations of load torque disturbance. In the proposed system, the speed control characteristic used a feedforward control which does not undergo the influence of the load torque disturbance. High speed calculation and processing for vector control is carried out by TMS320C31 digital signal processor. Validity of the proposed control method is verified through simulation and experimental result.