• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2003년도 추계학술대회 논문집
• /
• pp.1-5
• /
• 2003

The random pulse width modulation(RPWM) on the noise and vibration abatement in inverter-fed induction motor drive is presented. This paper describes a RPWM technique based on space vector PWM strategy for shaping the switching noise spectrum in such a way it can merge with the natural system noise. To verify the validity of the proposed RPWM scheme, the experiment based on the TMS320 C3l microprocessor was executed. Finally, the simulation and experimental results will be given to demonstrate the effectiveness of the proposed RPWM technique.

• 한국조명전기설비학회지:조명전기설비
• /
• 제9권3호
• /
• pp.88-96
• /
• 1995

고속 엘리베이터는 높은 안정성과 제어성이 필요하므로 기동, 정지시에 영 속도를 포함한 정밀 구동이 필요하다. 유도전동기의 정밀 구동을 위하여 사용되어온 벡터 제어 기법은 슬립 주파수 제어에 의한 간접 벡터 제어와 계자편향에 의한 직접벡터 제어의 두가지 종류로 분류할 수 있으며, 직접벡터제어의 경우 전동기 제어 변수의 변화에 강건한 반면에 직접 벡터 제어의 경우 비교적 넓은 속도구간에서 제어가 가능하다는 장점을 가지고 있다. 본 논문에서 토크는 직접 벡터기반으로 제어하고, 지속은 간접 벡터 기반으로 제어함으로써 유도전동기의 과도상태 동작과 시동시 영 속도 부근 및 저속 영역에서의 동작이 보다 강건하도록 개선된 직접토크-간접자속(DTIF, Direct Torque Indirect Flux)제어기를 제시하였다. 3상 유도전동기의 구동을 위하여 제안된 시스템의 수행결과는 시뮬레이션과 실험을 통하여 입증하였으며, 영 속도부근과 저속에서 고속으로의 변환과정은 속도응답에 대한 상전압, 상전류 그리고 DC링크 전류를 비교 측정하여 안정하고 강건한 속도변화가 이루어짐을 확인 할 수 있었다.

• 비파괴검사학회지
• /
• 제24권5호
• /
• pp.532-537
• /
• 2004

전자기장을 유도하는 원리를 기초로 한 새로운 비파괴탐상법인 FEF법을 개발하였다. 이 탐상법은 전자기장을 유도하는 유도선과 이를 감지하는 감지부로 구성되어 있고, 비접촉 방식으로 탐상을 실시한다. 본 연구는 알루미늄합금, 스테인레스강과 인코넬 합금강의 재료에 방전 가공한 결함에 대하여 결함 검출 및 결함 깊이에 대한 평가를 실시하였다. 결함이 없는 영역에서의 측정전압은 lift-off에 의존한다. 결함영역에서 탐촉자가 결함에 가까이 접근할수록 전압은 증가하고, 결함위치에서 최고전압으로 측정되며, 이 최고치는 결함의 깊이에 따라 변화한다. 각 재료에 대한 전압분포 같은 경향으로 측정된다.

• Journal of Electrical Engineering and Technology
• /
• 제12권2호
• /
• pp.761-768
• /
• 2017

This paper deals with the performance analysis of three phase induction motor considering its stator side faults and operating thermal limits. The speed control of induction motor using three phase boost converter operated by a MOSFET switch and a PI controller is demonstrated and presented in this article. IGBTs switches are used for inverter drive mechanism. The experimental result of speed control of induction motor using voltage control technique clearly shows better accuracy than conventional methods of speed control. A three phase 1HP 415V 0.78 kW 4 Pole induction motor is designed using motor solver software. Based on the parameters used in the software thermal analysis of induction motor is done and torque variation with conductor area, efficiency, output curve, losses in different parts of motor has been obtained. Also different types of faults namely under voltage, over voltage, stator imbalanced voltage, turn to turn, locked rotor bar, wrong alignment of rotor bar with respect to stator are studied and fault analysis is performed. Hence comparison is made based upon the results obtained before and after faults.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
• /
• pp.462-465
• /
• 2001

The wound induction motor can provide high starting torque and reduced starting current simultaneously by inserting large scale resistor. And this technique is one of the well known methods among the induction motor starting methods and generally used for heavy load starting such as Crain and Cement factories. The conventional PI controller has been widely used in industrial application due to the simple control algorithm and in general, PI controller is used for control of current, torque, position, and speed for the wound induction motor drive system. However, the system may result in poor performance since sensors have to be used, which in turn is limited by the environmental condition. Recently, to overcome these problems, many sensorless vector control methods for the wound induction motor have been studied. This paper presents MRAS method with on-line stator resistance tuning for sensorless vector control of the wound induction motor drive. In conventional MRAS method, in low frequency, stator resistance variation can result in poor performance. Therefore, to overcome several shortages of the conventional MRAS caused by parameter variation and enhance robustness of the sensor less vector control, this paper investigates a MRAS method with on-line stator resistance tuning for sensorless vector control of the wound induction motor. The validity and effectiveness of the proposed method is verified through digital simulation.

• Journal of Electrical Engineering and Technology
• /
• 제4권2호
• /
• pp.219-228
• /
• 2009

The growing application and the numerous qualities of induction motors (1M) in industrial processes that require high security and reliability levels has led to the development of multiple methods for early fault detection. However, various faults can occur, such as stator short-circuits and rotor failures. Traditionally the diagnosis machine is done through a sinusoidal power supply, in the present paper we study experimentally the effects of the rotor failures, such as broken rotor bars in function of the ac supplying, the load and show the impact of the converter from diagnosis of the machine. The technique diagnosis used is based on the spectral analysis of stator currents or stator voltages respectively according to the types of induction motor ac supplying. So, four different ac supplying are considered: ${\odot}$ the IM is directly by the balanced three-phase network voltage source, ${\odot}$ the IM is fed by a sinusoidal current source given the controlled by hysteresis, ${\odot}$ the IM is fed (in open loop) by a scalar control imposing through ratio V/f=constant, ${\odot}$ the IM is controlled through a vector control using space vector pulse width modulation (SVPWM) technique inverter with an outer speed loop.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2005년도 ICCAS
• /
• pp.1439-1444
• /
• 2005

Induction motors are the most commonly used electrical drives because they are rugged, mechanically simple, adaptable to widely different operating conditions, and simple to control. The most common faults in squirrel-cage induction motors are bearing, stator and rotor faults. Surveys conducted by the IEEE and EPRI show that the most common fault in induction motor is bearing failure (${\sim}$40% of failure). Thence, this paper addresses experimental results for diagnosing faults with different rolling element bearing damage via motor current spectral analysis. Rolling element bearings generally consist of two rings, an inner and outer, between which a set of balls or rollers rotate in raceways. We set the experimental test bed to detect the rolling-element bearing misalignment of 3 type induction motors with normal condition bearing system, shaft deflection system by external force and a hole drilled through the outer race of the shaft end bearing of the four pole test motor. This paper takes the initial step of investigating the efficacy of current monitoring for bearing fault detection by incipient bearing failure. The failure modes are reviewed and the characteristics of bearing frequency associated with the physical construction of the bearings are defined. The effects on the stator current spectrum are described and related frequencies are also determined. This is an important result in the formulation of a fault detection scheme that monitors the stator currents. We utilized the FFT, Wavelet analysis and averaging signal pattern by inner product tool to analyze stator current components. The test results clearly illustrate that the stator signature can be used to identify the presence of a bearing fault.

• Journal of Power Electronics
• /
• 제13권2호
• /
• pp.322-328
• /
• 2013

This paper presents a modified Current Source Parallel Resonant Push-pull Inverter (CSPRPI) for single phase induction heating applications. One of the most important problems associated with current source parallel resonant inverters is achieving ZVS in transient intervals. This paper shows that a CSPRPI with the integral cycle control method has dynamic ZVS. According to this method, it is the Phase Locked Loop (PLL) circuit that tracks the switching frequency. The advantages of this technique are a higher efficiency, a smaller package size and a low EMI in comparison with similar topologies. Additionally, the proposed modification results in a low THD of the ac-line current. It has been measured as less than %2. To show the validity of the proposed method, a laboratory prototype is implemented with an operating frequency of 80 kHz and an output power of 400 W. The experimental results confirm the validity of the proposed single phase induction heating system.

• Journal of Electrical Engineering and Technology
• /
• 제6권2호
• /
• pp.226-232
• /
• 2011

The $H_{\infty}$ approach, adopted in this paper, is based on loop shaping using a normalized coprime factor combined with a field-oriented control to control induction motor. We develop two loops. The first one, the inner loop, controls the stator current by $H{\infty}$ controller in order to obtain good performance. The second loop, the outer one, guarantees stability and tracking performance of speed and rotor flux using a proportional integral controller. When the rotor flux cannot be measured, we introduce a flux observer to estimate the rotor flux. Simulation and experimental results are presented to validate the effectiveness and the good performance of this control technique.

• Journal of Power Electronics
• /
• 제16권4호
• /
• pp.1346-1354
• /
• 2016

This paper proposes a design guideline for the feedback gain of the adaptive full-order observer in the speed sensorless control of induction machines. The performance of the adaptive full-order observer is dependent on its feedback gain. This paper presents a pole placement method for the observer feedback gain design to improve the estimation performance of the speed adaptive observer. In the proposed method, the observer poles can be chosen independently of the induction motor poles. Instead, they can be positioned according to the operating speed. An analysis and experimental results obtained with the proposed method reveals better performances under general operating conditions.