• 한국전기전자재료학회논문지
• /
• 제18권9호
• /
• pp.863-869
• /
• 2005

We investigated quench characteristics of superconducting elements connected in series and parallel each other. The serial and parallel connections of superconducting elements causes a difficulty in simultaneous quench due to slight difference between their critical current densities. In other to induce simultaneous quench, we fabricated four type circuits; serially connected circuit before parallel connection, the circuit connected in parallel before serial connection, serially connected circuit before parallel connection with reactors, the circuit connected in Parallel before serial connection with reactors. We confirmed that the simultaneous quenches occurred in serial and parallel connections of superconducting elements using reactors. In addition, the power burden of superconducting elements was smaller than those of serial and parallel connections of superconducting elements without reactors.

• 전기학회논문지
• /
• 제56권12호
• /
• pp.2078-2083
• /
• 2007

We have analyzed operating characteristics of transformer-type superconducting fault current limiter (SFCL) according to the serial or parallel connections of secondary coils with $YBa_2Cu_3O_7$ (YBCO) thin films. The turn ratio between the primary and secondary coils was 63:21. Transformer-type SFCL using a transformer with secondary winding of serial or parallel coils could reduce the unbalanced quench caused by differences of the critical current density between YBCO thin films. We found that transformer-type SFCL having serial or parallel connections induced simultaneous quench between the superconducting units. The limiting current in the transformer-type SFCL with a parallel connection was lowered to 30 % compared to the SFCL with a serial connection. In the meantime, when the currents generated in the superconducting units were similar, the voltage value in the parallel connection was 60 % as low as that in the serial connection. However, the voltage generated in the primary winding was some higher. In conclusion, we found that transformer-type SFCL with parallel connection of secondary coils was more effective in fault current limiting characteristics and in the reduction of the consumption power for superconducting units compared to those of the transformer-type SFCL with serial connection of secondary coils.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.393-395
• /
• 2006

We investigated the operational characteristics of the hybrid-type superconducting fault current limiter (SFCL) according to the serial and parallel connections of secondary circuits. The hybrid-type SFCL consists of a transformer, which has a primary winding and several secondary windings with $YBa_2Cu_3O_7$ films connected in series and parallel. In order to increase the capacity of the SFCL, the serial connection between each current limiting unit is necessary. The hybrid-type SFCL with the serial connection in secondary circuits could show superior characteristics than those of the parallel connections in the current limiting and quench time. The resistances generated in the superconducting units were also lowered at the parallel connections. We confirmed that the parallel connection reduced the power burden of each superconducting unit under the same conditions because of the simultaneous quenching between superconducting units.

• 전기학회논문지P
• /
• 제57권3호
• /
• pp.323-327
• /
• 2008

We investigated the quench characteristics of a flux-lock type superconducting fault current limiter (SFCL) depending on the methods of the serial and parallel connections between the superconducting elements. The flux-lock type SFCL consists of two coils. The primary coil is wound in parallel to the secondary coil through an iron core, and the secondary coil is connected to the superconducting elements in series and parallel. In this paper, the analyses of voltage, current, and resistance of the superconducting elements connected in serial and parallel were performed to increase the power capacity of the flux-lock type SFCL. A part of the superconducting elements was not quenched in $2{\times}2$ serial connection between the elements and then the power burden of the quenched elements was increased. However the elements with $2{\times}2$ parallel connection was all quenched. This means that the power burden of each superconducting element can be reduced under the same conditions. We found that $2{\times}2$ parallel connection was more profitable for the current limiting effects and the increase of the power capacity.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 추계학술대회 논문집 전력기술부문
• /
• pp.87-88
• /
• 2007

We investigated the current limiting characteristics of flux-lock type superconducting fault current limiter using YBCO films University, Gwangju health college. The flux-lock type SFCL consisted of the transformer with a primary winding and a secondary winding connected in parallel, and the superconducting element was connected with secondary winding in series or parallel. Serial and parallel connections of superconducting elements are necessary for the increase of voltage and current capacities when we intend to apply the flux-lock type SFCL.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2002년도 추계학술대회 논문집
• /
• pp.213-217
• /
• 2002

Power devices for high power drivers that need high switching speed (IGCT, HVIGBT) have been continuously developed. However, serial and parallel connections using several much cheaper, lower power capacity of devices than an expensive high power device are very useful methods in the aspect of cost down and high power application. Even the current and voltage unbalance problem is occurred at each devices. This unbalance characteristics are mainly caused by the differences of physical characteristics of each devices and the line inductance (stray inductance) of bus bars that consist of current path. This paper deals simulation analysis of serial connection of IGCTs and parallel connection of IGCTs using physical model of devices. And also, introduces the method to reduce the voltage and current unbalance problem.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2008년도 추계학술대회 논문집
• /
• pp.85-87
• /
• 2008

This paper presents dynamic characteristics in Switched Reluctance Motor (SRM) with rotor eccentricity and proposes the reduction method of rotor eccentricity effects by the different winding connections. These characteristics investigations are computed by 2D transient magnetic FEM analysis coupled with external circuits. The radial and unbalance magnetic force in the stator, which is the main exciting force of the vibration, is calculated using Maxwell stress method and compared with the performance characteristics according to the serial and parallel connections of windings. The influence of winding method counteracting unbalance forces on the rotor vibration behavior is estimated by the current waveforms of the paralleled paths under rotor eccentricity.

• 전기학회논문지P
• /
• 제58권1호
• /
• pp.27-32
• /
• 2009

A technical system generally comprise a number of subsystems and components that are interconnected in such a way that the system is able to perform a set of required function. Because of the complex system structure with serial, parallel and bridged connections, some certain subsystems or components are more critical than the others. The main concern of a reliability engineer is to identify potential failures and to prevent these failures from occurring. In order to prevent fatal failures, proper inspections and maintenance actions for each component are required Considering above objectives of reliability engineers and characteristics of a practical system, several practical method for evaluating system and component reliabilities have developed namely Birnbaum's and Fussell & Vesely's measures. However there are several critical weaknesses in traditional calculation process as the target system gets larger. In this paper, a new technique for calculating component's structural importance is proposed and compared to Birnbaum's with representative system examples (serial, parallel. k out of n, and bridge type).

• 전력전자학회논문지
• /
• 제22권3호
• /
• pp.249-255
• /
• 2017

This paper presents air-gap control according to Y and Delta connections of a double-sided air-gap permanent magnet synchronous motor (DA-PMSM) with independent three-phase structure. In particular, the DA-PMSM used in this study can be applied to low-speed and high-torque applications, such as wind turbines, tidal power generations, and electric propulsion ships, because of its modular stators and a rotor with numerous permanent magnets. Unlike conventional three-phase machines, the DA-PMSM has a symmetrical configuration with double-sided air-gap. Therefore, Y/Delta winding connections and serial/parallel configurations between stator modules are possible. To identify the DA-PMSM operating characteristics, mathematical modeling is analyzed according to the Y/Delta connections. Moreover, air-gap control performances by applying the winding connection methods are verified through experimental results.

• 대한의용생체공학회:의공학회지
• /
• 제17권4호
• /
• pp.459-468
• /
• 1996

This paper considers the problem of realising a parallel EMG identifier used in FES (functional electrical stimulation) system on a fixed dimension transputer array. This involves using an identifiestion algorithm in the wavelet transform domain. This algorithm have suggested by the authors in a previous paper(6). The transputer serial links permit higtlly varied and economic network-type connections and the structure enables rapid topological reconfiguration. Analysing the results Showed that the Speed-UPS ranged from 1.82 to 3.44 With 2-4 transputers for corresponding model order, and from 1.82 to 3.97 with increasing the model orders when two and four transputers are used respectively.