• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 하계학술대회 논문집 D
• /
• pp.2492-2494
• /
• 2004

A system, featuring the electromagnetic levitation actuator for control in the vertical direction, of active microvibration control was proposed. The main components of this system are a vibration isolation table with built-in acceleration sensors for detecting microvibration, electromagnetic levitation actuators with built-in permanent magnets and electromagnets, and a digital controller with high precision signal converters.

• Journal of Mechanical Science and Technology
• /
• 제17권1호
• /
• pp.40-47
• /
• 2003

In this paper, we constructed the analytic model of control valve as a function of electric and geometric parameters, and analyzed the influence of the design parameters on the dynamic characteristics. For improving the dynamic characteristics, optimal design is conducted by applying sequential quadratic programming method to the analytic model. This optimal design aims to minimize the response time and maximize force efficiency. By this procedure, control valve can be designed to have fast response in motion.

• 전기의세계
• /
• 제30권1호
• /
• pp.55-63
• /
• 1981

This paper deals with the drive contrl of common elevator systems which may be realized with .mu.p-controlled selective-collective elevator systems. Incorporation on non-contact point circuits instead of electromagnetic relays in such an elevator system results in miniaturization of complicated hardware controllers currently being used. The drive control method is implemented by software programming. The important features are not only technical advantages such as higher performance, high speed data processing and more improved reliability, but also lower cost as compared with the conventional elevator drive control units equipped with a number of sequential electromagnetic relays and even more recent static IC logic circuits.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 춘계학술대회논문집B
• /
• pp.65-69
• /
• 2001

In this study, the deformation of the free surface motion of a magnetic fluid for the change in electromagnetic force is discussed. In case, magnetic fluid in characteristics of fluid adjusted to the opposite direction of the gravity direction. Thus, the device of a magnetic fluid proposed the complete zero-leakage Sealing and the surface actuator. The device of surface deformation as well comparison between numerical simulation and experiments as will be presented.

• Journal of Electrical Engineering and Technology
• /
• 제11권5호
• /
• pp.1423-1432
• /
• 2016

• International Journal of Aeronautical and Space Sciences
• /
• 제4권2호
• /
• pp.69-78
• /
• 2003

In this paper, we develop the so-called functional test model for magnetic bearing wheels. The functional test model developed in this paper is a kind of electromagnetic suspension systems and has three degree of freedom, which consists of one axial suspension from gravity and the other two axes gimbaling capability to small angle, and does not include the motor. For the control of the functional test model, we derive the optimal electromagnetic forces based on the least squares method, and use the proportional-integral derivative controller. Then, we develop a hardware setup, which mainly consists of the digital signal processor and the 12-bit analog-to-digital and digital-to-analog converters, and show the experimental results.

• Journal of Electrical Engineering and Technology
• /
• 제9권2호
• /
• pp.523-531
• /
• 2014

Brushless Dual-Mechanical-Port Electrical Machine (BLDMPEM) is a new type of motor designed for Hybrid Electric Vehicle (HEV), which contains two mechanical ports and two electric ports. Compared with Dual-Mechanical-Port Electrical Machine (DMPEM), the brushless structure brings higher reliability and easier maintenance. In this paper, the model of BLDMPEM is discussed. In Chapter 2, the energy flow and mathematical model of BLDMPEM are analyzed. Then a novel three-phase half-bridge controlled rectifier topology and its control strategy for cruising mode of HEV based on BLDMPEM are proposed in Chapter 3. Compared with the Field Oriented Control (FOC) strategy of BLDMPEM, the proposed method does not require accurate motor parameters, and it is much simpler and easier to be implemented. At last, simulation and experiment results show the feasibility and validity of the proposed strategy.

• Journal of Power Electronics
• /
• 제15권5호
• /
• pp.1286-1294
• /
• 2015

Capacitor current feedback active damping is extensively used in grid-connected converters with an LCL filter. However, systems tends to become unstable when the digital control delay is taken into account, especially in low switching frequencies. This paper discusses this issue by deriving a discrete model with a digital control delay and by presenting the stable region of an active damping loop from high to low switching frequencies. In order to overcome the disadvantage of capacitor current feedback active damping, this paper proposes a modified approach using grid current and converter current for feedback. This can expand the stable region and provide sufficient active damping whether in high or low switching frequencies. By applying the modified approach, the active damping loop can be simplified from fourth-order into second-order, and the design of the grid current loop can be simplified. The modified approach can work well when the grid impedance varies. Both the active damping performance and the dynamic performance of the current loop are verified by simulations and experimental results.

• 한국어병학회지
• /
• 제30권1호
• /
• pp.51-61
• /
• 2017

The effect of electromagnetic field on aquatic organisms has received little attention. In the current study, the effect of 50Hz electromagnetic field on muscle histopathology of Caspian Sea Cyprinus carpio, a species of economic importance, was investigated. A total of 120 healthy fish were used in this study. They were classified randomly in one of two groups as follows: Control or unexposed EMF group and experimental group with 5 different magnetic field intensities (0.1, 1, 3, 5 and 7mT) at 2 different exposure times including 30 and 60 minutes. Fish in the experimental group were exposed only once. Two weeks after exposure, dorsal muscles sectioned transversely, stained and were examined using a light microscope. Histopathologic assessments showed significant difference between control and EMF exposed groups at both 30 min. (p<0.01) and 60 min. (p<0.001) exposure times. We report for the first time that electromagnetic field in interaction with muscular tissue of Cyprinus carpio exhibits a dual effect which depends on the field intensity, and exposure time. At short exposure time (30 min.), EMF stimulates muscle growth process. At longer exposure time (60 min.), EMF can damage muscle tissue and result in muscle necrosis. More research is required to elucidate precise mechanisms involved in muscle hypertrophy and pathologic changes.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2009년도 추계학술대회 논문집
• /
• pp.299-304
• /
• 2009

A hybrid electromagnetic actuator with an air spring is designed so as to achieve the desired isolation reduce the vibration efficiency on the floor vibration. The performance specification of the hybrid electromagnetic actuator is determined based on the vibration criterion for vibration-sensitive equipment. In basic design stage of the electromagnetic actuator, the simple reluctance method is adapted to analyze magnetic circuits. The result is verified by finite element analysis using ANSYS Emag. Finally, some design parameters are optimized under several constraint conditions. Through this study, the design procedure for a specific electromagnetic actuator is set up using a simple reluctance method.