• Proceedings of the KIEE Conference
• /
• 2001.04a
• /
• pp.277-280
• /
• 2001

This paper presents a speed sensorless implementation of digital speed control system of Surface Permanent-Magnet Synchronous Motor(SPMSM) drives with a direct torque control(DTC). The system presented are stator flux and torque observer of stator flux feedback control model that inputs are current and voltage sensing of motor terminal with estimated rotor angle for a low speed operating area, two hysteresis band controllers, an optimal switching look-up table, rotor speed estimator, and IGBT voltage source inverter by using fully integrated control software. The developed speed sensorless control system are shown a good motion control response characteristic results and high performance features using 1.0Kw purposed servo drive SPMSM.

• Proceedings of the KIEE Conference
• /
• 2001.04a
• /
• pp.345-348
• /
• 2001

In this paper, the development of input power factor and harmonic distortion of line current were showed in the proposed single-stage SRM inverter. It is verified from the experiments that the proposed encoder and logic controller can be a powerful candidate for the practical low cost SRM drive.

• Proceedings of the KIEE Conference
• /
• 2006.07b
• /
• pp.1031-1033
• /
• 2006

In this study, in order to solve these problems, a new type of electronic ballast, which is composed of rectifier, active power factor corrector, series resonant half bridge inverter and piezoelectric transformer, was proposed for driving T5 fluorescent lamp. Driving of piezoelectric transformer was carried out with input region for the ring electrode and output region for the dot electrode. A 35W (T5) fluorescent lamp was successfully driven by the fabricated ballast with piezoelectric transformer.

• Proceedings of the KIEE Conference
• /
• 1997.07a
• /
• pp.74-76
• /
• 1997

This paper describes the implementation for electrical quanties and mechanical quanties monitoring system of the LIM driven by a inverter. The monitoring system can be display the characteristics of it's quanties, such as voltage, current, power, power factor, frequency, apparent power, thrust, speed, position, normal force, on the real time.

• The KSFM Journal of Fluid Machinery
• /
• v.18 no.6
• /
• pp.76-80
• /
• 2015

The purpose of this study is to understand the cavitation phenomena in centrifugal pumps through computational fluid dynamics method. NPSH characteristic curve is measured from different flow operating conditions. Steady state, liquid-vapor homogeneous method with two equations transport turbulence model is employed to estimate the NPSH curve in centrifugal pumps. The Rayleigh-Plesset cavitation model is adapted as source term for inter-phase mass transfer in order to understand cavitation phenomena in centrifugal pumps. The cavitation incipient curve is clearly estimated at different flows operating conditions. A relationship is made between cavitation incipient and NPSH curve. Also the effects on water vapor volume fraction and pressure load distributions on the impeller blade are also described.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.12 no.2
• /
• pp.157-157
• /
• 1998

이 논문은 브리시리스 직류전동기의 구동 인버터의 실시간 데이터를 이용한 고장진단에 관한 것이다. 구동 인버터의 고장유형을 파악하여 주요 고장증세별로 분류하고, 고장결과를 예측하여 ASCL로 시뮬레이션함으로써 지식 베이스로 구성하였다. 구동 인버터에 대해 실시간으로 감시된 데이터는 전문가 시스템의 추론기관에서 시뮬레이션된 지식베이스와 비교하게 된다. 고장이 발생하면, 운전을 중지시킨 후, 전문가 추론을 함으로써 고장원인을 진단한다. 이로써 구동 인버터에 대해 전문적인 지식을 갖고 있지 않는 사용자에게, 고장원인 제거 및 수리대책에 관한 전문가의 지식을 신속히 제공하는 것이다.

• Proceedings of the KIPE Conference
• /
• 2005.07a
• /
• pp.587-590
• /
• 2005

In this paper, the PWM inverter-motor drive system including sensor is controlled through the network. The algorithm to compensate for the time delay of ac current and ac voltage sensors due to the network is proposed. The delay time of sensors is kept nearly constant, using the synchronous signal and timers. The error between the real and estimated ac signals can be reduced by using two slopes for estimating the value of at signals. The proposed algorithms are verified with the simulation studies and experiments.

• Proceedings of the KIPE Conference
• /
• 2005.07a
• /
• pp.36-38
• /
• 2005

In home appliances, electric energy is optimally controlled by using power electronics technology, creating a comfortable environment in terms of energy saving, low sound generation, and reduced time consumption. Usually simplicity and robustness make the three phase induction motor attractive for use in domestic appliance, including washing machines. Two main types of domestic washing machine have evolved. We focus on the front loading machine favored in Europe, which has a horizontal drum axis. The efficiency improvement in home appliances is very important for customers. Induction motor efficiency can be improved by means of loss reduction, which can be realized by motor selection and design, improvement of the waveforms supplied by power Inverter, utilizing a suitable control method. So this paper describes the architecture and feature of washing machine fed induction motor drive under minimizing losses vector control.

• Proceedings of the KIPE Conference
• /
• 2005.07a
• /
• pp.39-41
• /
• 2005

In this paper, a study on the controller for high speed PMSM (Permanent Magnet Synchro-nous Motor) is described. PMSM can be driven over 50,000 rpm because it has no brush and commutator structure. It also has less EMI noise and easy cooling structure compare to the other motors. The controller was designed to have a capability to drive 20kw, 42,000rpm high speed motor system. A senseless vector control method was studied based on d-q conversion theory to have a high driving efficiency. The control board was designed using TMS320C33 and the performance was verified by experimental results on driving the inverter and motor system.

• Proceedings of the KIPE Conference
• /
• 2013.07a
• /
• pp.112-113
• /
• 2013

본 논문에서는 부트스트랩 게이트 드라이브 회로가 적용된 3-레벨 NPC 인버터의 전동기 저속 운전에 적용하기 위한 PWM 스위칭 전략을 제안한다. 3-레벨 NPC 인버터를 이용하여 전동기를 제어할 경우, 일반적으로 구현의 편리성 때문에 CBPWM이 주로 사용된다. CBPWM 중 Unipolar 방법이 주로 사용되지만 부트스트랩 회로를 적용한 3-레벨 NPC 인버터의 전동기 저속 운전 시 부트스트랩 캐패시터 방전에 의한 전압 감소 크기가 증가한다. 캐패시터 전압이 정상적인 인버터 동작을 위한 한계 전압 이하로 감소하면 정상적인 제어는 불가능하다. 따라서 본 논문에서는 부트스트랩 회로가 적용된 3-레벨 NPC 인버터의 전동기 저속 운전에 적용하기 위한 PWM 스위칭 전략에 대해 제안 하였으며 시뮬레이션을 통하여 그 타당성을 증명하였다.