• Proceedings of the KIEE Conference
• /
• 1996.07a
• /
• pp.104-106
• /
• 1996

In this paper, the dynamic motion driven by electromagnetic force of transformer windings is modeled and its characteristics are numerically analyzed. The electromagnetic field is obtained using the 2D finite element method taking account of anisotropic property of iron core, and the electromagnetic force on the transformer winding is calculated from Lorenz's force formula using the field distribution result. The system motion equation driven by electromagnetic force and gravitational force is numerically analyzed using the 4-order Runge-Kutta algorithm. Above analyses procedure is applied to a single-phase core-type transformer to validate its algorithm.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.34 no.7
• /
• pp.267-275
• /
• 1985

The finite element method for calculating single phase transformer inductance is presented in this paper. There are three basic definitions of saturated transormer inductance. The set of nonlinear finite element equations is solved by the Newton-Raphson method which assures nearly quadratic convergence of the iteration process. The effect of perturbation of currents of this transformer is used to calculate the saturated winding inductance. This approach is used to calculate the apparent, effective and incremental inductance of single phase transformer. The apparent inductance is in good agreement with resting result. The approach enabled one to study the variation of winding inductance according to the saturation levels in the core at any operating point.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.63 no.3
• /
• pp.125-130
• /
• 2014

This paper is research result for a development of solar cell silicon ingot glowing(SCSIG) PWM converter system for 120[kW] 3[kA]. The system include 3-phase AC-DC rectifier diode converter of input voltage AC 460[V] and 60[Hz], DC-AC single phase full bridge PWM inverter of high frequency, AC-DC single-phase full wave rectifier using center-tapped of transformer for low voltage 50[V] and large current 3,000[A], carbon resistor load 0.2 [$m{\Omega}$]. PWM switching frequency for IGBT inverter control set 15KHz. The suggested researching contents are designed data sheets of power converter system, PSIM simulation, operating characteristics and analysis results of developed SCSIG system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.28 no.11
• /
• pp.33-41
• /
• 2014

This paper is research result for a development of sapphire silicon ingot glowing(SSIG) PWM converter system for 80kW 10kA. The system include 3-phase AC-DC diode rectifier of input voltage AC 380V and 60Hz, DC-AC single phase full bridge PWM inverter of high frequency, AC-DC single-phase full wave rectifier using center-tapped of transformer for low voltage 8.0V and large current 10,000A of output specification, tungsten resistor load 0.1[$m{\Omega}$]. PWM switching frequency for IGBT inverter control set 30kHz. The suggested researching contents are designed data sheets of power converter system, PSIM simulation, operating characteristics and analysis results of developed SSIG system. This paper propose

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
• /
• v.5B no.3
• /
• pp.243-247
• /
• 2005

The Different-volume- V-connection transformer is known as an electric power source that can supply 3-phase electric power and single-phase electric power at the same time. Usually, we use two single-phase transformers that have different volumes. In this paper, we propose the use of a 3-phase 5-leg transformer with the different-volume- V-connection. And, we examine the magnetic properties of the 5-leg core model with the different-volume- V-connection. The magnetic properties of cores with the different-volume- V-connection are compared with those with the delta-connection. In order to express the magnetic anisotropy of the core materials and to calculate the iron loss directly, the two-dimensional vector magnetic property is considered with the E&SS modeling in the simulation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.20 no.6
• /
• pp.87-95
• /
• 2006

In this study, in order to obtain high qualify of electric power, single phase active filter which is composed of Zig-Zag transformer and three phase bridge rectifier and capacitor at the secondary of its transformer to be able to reduce the components of the zero phase current and the third harmonic current in neutral line and power line respectively. By connecting this filter to the Zig-Zag transformer and nonlinear load, their third harmonic components due to the nonlinear loads were reduced.

• Progress in Superconductivity and Cryogenics
• /
• v.5 no.3
• /
• pp.34-37
• /
• 2003

A 1 MVA single-phase high temperature superconducting (HTS) transformer with BSCCO-2223 wire was designed in this paper. The rated voltages of each sides of the transformer are 22.9 kV and 6.6 kV respectively. Double pancake HTS windings arranged reciprocally will be used for the transformer windings, because of the advantages of insulation and distribution of surge voltage in case of a large power and high voltage transformer. Single HTS wire was used for the primary windings and four parallel wires were used for the secondary windings of the transformer with transposition. A core of the transformer was designed as a shell type core separated with the windings by a cryostat made of GFRP with a room temperature bore. The operating temperature of the HTS windings will be about 65K with sub-cooled liquid nitrogen. A cryogenic cooling system using a GM-cryocooler for this HTS transformer by natural convection of liquid nitrogen was designed. This type of cooling system can be a good option for compactness, efficiency, and reliability of the HTS transformer.

• Proceedings of the KIPE Conference
• /
• 2001.07a
• /
• pp.356-359
• /
• 2001

In this paper, the new control algorithm is proposed that compensates instantaneously the active and reactive components of the input currents by the synchronous d,q axis conversion of a single-phase current in controlling the single-phase AC/DC parallel converters for a high speed train. The leakage inductance of a transformer was used as a boost inductance and the ripple of a transformer's primary current was reduced considerably by the parallel operation of the two converters with a proper switching phase-shift. The stable and fast control response characteristic is certificated by a simulation.

• Progress in Superconductivity and Cryogenics
• /
• v.9 no.1
• /
• pp.67-71
• /
• 2007

HTS transformers which have been developed until now had only fundamental structures. Among the auxiliary functions of conventional transformers, voltage regulating is the most important one. For the voltage regulation, conventional transformers are equipped with on load tap changers (OLTCS). In this paper, we describe the possibility of the HTS transformer with OLTC. For the case study, we designed a single phase 33 MVA HTS transformer with OLTC. It is one of three individual HTS transformers which composes a 3 phase, 100 MVA transformer. It is expected to substitute for a 3 phase, 60 MVA conventional transformer in Korea. The parameters of an HTS transformer are varied due to the gap length between primary and secondary windings. The length was decided for the transformer to have the impedance of 12 %. Its size was limited to the one of the conventional transformer. The characteristics of the HTS transformer were analyzed in both case of having OLTC and not.

• Proceedings of the KIPE Conference
• /
• 2000.07a
• /
• pp.355-359
• /
• 2000

This paper deal with the harmonic reduction technique in three-phase square-wave inverter system formed by single-phase inverter. To reduce the harmonics six single-phase inverters are used for forming multi-phase inverter and zig-zag connected output transformer for eliminating the harmonic 6(2k-1)$\pm$1 orders. And an ac filter is furnished at output side. Computer simulations show that the THD of the output voltage can be reduced immensely.