• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.4
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• pp.595-600
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• 2023

In this paper, a modified equations of the T-equivalent circuit of the transmission line with the arbitrary electrical length is suggested. The suggested equations can be calculated without limitation of the equal branch-line. So, a modified T-equivalent circuit can be made with the arbitrary position of the open-stub. Also, the modified T-equivalent circuit can be applied in the arbitrary electrical length and impedance of the transmission line. For example, the λ/4 impedance transformer is converted with 4 divided T-equivalent circuit. The converted λ/4 impedance transformer has the size reduction ratio of 39.4%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.6
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• pp.1180-1185
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• 2009

In this paper, the Low Pass Filter (LPF) using the equivalent circuit of T-junction microstrip line is proposed. And we derived the formulas for lumped-elements of the equivalent circuit of T-junction microstrip line to solve the frequency shift characteristic. T-junction microstrip line is de-embedded by Electromagnetic simulation tool and exact lumped element value of T-junction microstrip line is calculated by the equation of Z-parameter. We can get excellent agreement between lumped-element LPF frequency response and transmission line LPF frequency response.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.80-82
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• 1988

This paper proposed a new equivalent circuit and parameter estimation for I.M, which is different from T type and L type equivalent circuits. By using this circuit, we can analyze the torque of I.M, such as seperately exited D.C Motor, further more, we think that this equivalent circuit is effective to the vector control system for I.M.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.805-807
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• 2002

In this paper, a method for an accurate and fast transient analysis, which employs a single slot model for the rotor, is presented. The equivalent circuit parameters are extracted from a combined method of F. E. M and equivalent circuit on 1 slot rotor boundary condition. Two kinds of circuit parameters for each slip are applied to equivalent circuit controlled by variable-voltage variable- frequency. One is the constant parameters at rated speed, and the other is the parameters varying in accordance with slip-frequency. The computer characteristics of the suggested method for four-pole 1.5KW induction motor are compared with those of Equivalent circuit for the transient analysis.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.47-49
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• 1996

The equivalent circuit of LIM is generally composed as the same that of rotary induction motor. However it is very difficult to move the LIM at synchronous velocity for open-secondary circuit test. The resistance representing the core losses in the primary core can not be ignored because the air-gap of LIM is larger than that of rotary induction motor. In this paper, the T-type equivalent circuit of a LIM with the core loss resistance is chosen using static zero slip test and theoritical analysis.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.6
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• pp.90-95
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• 1997

In designing a resonant circuit of the inverter which puts induction heating with high frequency to the load, an inductance L of the circuit, the coupling coefficient of a transformer transfering the output power to load, and the coupling coefficient of load circuit heating with coil affect to the output power of a resonant circuit, the circuit Q and the frequency. Those characteristics of the circuit are analyzed through Thevenan's equivalent circuit of the coupling coefficient type which is derived from the T-type equivalent circuit of a transformer. On this equivalent circuit, the impedance of a transformer referred to its primary side is not only proportional the square of turn ratio, nZ, but also the square of coupling coefficient, K2 This paper proposed a more accurate fundamental method to design a resonant circuit of the inverter by using the Thevenan's equivalent circuit.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.388-393
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• 1988

New circuit D-Q transformation concept is introduced to analyze AC converters such as inverters, rectifiers and cyclo-converters with ease. The equivalent linear time invariant circuit is obtained by substituting switches with equivalent turn-ratio variable transformers and changing balanced AC reactors into equivalent DC reactors combined by gyrators. This circuit enables us to utilize the powerful linear system analysis techniques such as Laplace transform otherwise which could not be applied to the time varying switching systems. Direct substitution of switches of DC converters with transformers is shown as a preliminary. Then the modeling procedure is shown for a controlled rectifier-inverter circuit. Finally an analysis example is proposed for a buck-boost inverter and the result is compared with the conventional approach. This approach is applicable to all AC converter families to determine the AC transfer functions and the DC operating points. It is identified that the switching systems are equivalent to the RLC filter circuits with transformers and gyrators.

• 전기의세계
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• v.22 no.1
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• pp.42-51
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• 1973

The contriving equivalent circuit of single phase induction motor which does not separate the primary leakage reactance and the secondary leakage reactance by the revolving field theory, and the graphically calculating method of the characteristics with T-type circle diagram of three phase induction motor which does not suppose the primary leakage reactance can be drawn up only by the no load test, the lock test, and measuring the resistance of stator winding are suggested in this paper. The method which can calculate the parameters of the equivalent circuit and the characteristics with no load test, lock test and measuring resistance of stator windings is suggested in this paper. Considered the exciting current in lock test, we could calculate very accurate characteristics of the single phase induction motor.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.4
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• pp.401-406
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• 2002

A microstrip circuit with multilayer structure is applied variously in the MMIC. For effective transmission between microstrip lines with different dielectric height, it is need to analyze and to induce accurately the equivalent circuit in 3 dimensional stepped discontinuous microstrip line. In this paper, by using the S parameters obtained by FDTD numerical method and measurement, T equivalent circuit and its element values were induced. And the analyzed and measured results showed good agreement in 1 ∼5 ㎓ range.

• Journal of Advanced Marine Engineering and Technology
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• v.9 no.1
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• pp.61-73
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• 1985

The induction motor is widely used in the power equipments of the ship and the various industrial drive applications because it is robust and relatively simple and cheap to manufacture, but it has a disadvantage that the speed of induction motor is not controlled in wide range such as d.c motor. In this paper, the characteristics relating to the Kramer system that the speed of three phase wound type induction motor is controlled by changing the exciting e.m.f. of the secondary circuit is described. In order to analyze the characteristics, a new simplified and approximated T-type equivalent circuit from the Kramer circuit with three phase graetz connection and d.c machine is proposed. The stator current, motor torque and mechanical output power are computed by the current, torque and power equations derived by its equivalent circuit. Through the experiments, the $I_f-N$, torque-slip and current-slip characteristic curves of the tested motor are obtained and the various needed constants are determined. The numerical values obtained from the above method are compared with experimental values under the same conditions. As a result of the above investigation, it is found that the induction motor speed by the Kramer system is controlled by 28 per cent under the rated speed by changing the field current of d.c motor and the values computed by the current and torque equations derived by the simplified and approximated T-type equivalent circuit generally come to approach the experimental values.