• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.55-59
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• 1991

This paper deals with the control stratege for the constant voltage, constant frequency(CVCF) generation of doubly-fed induction generator. As an induction machine is a nonlinear and multivariable machine, so, the control system is needed a very sophiticated control processes to meet a CVCF condition. In this paper, control system is constructed and tested using the suggested exitation equation. The test results show that the suggested equation and control system are very useful strategy for the CVCF control of induction generator.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.45-48
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• 1990

This paper deals with the control strategy for constant voltage, constant frequency (CVCF) generation of doubly-fed Induction generator. As induction machine is a nonlinear and multivariable machine, so, the influential factors for CVCF generation of induction generator are the magnitude of output voltage, load current and its power factor, slip of the machine, etc. To get appropriate control scheme and to research the effect of its parameters, the control equation of induction machine is derived and tested. The derived condition is very useful for the CVCF control of the machine and for determing the characteristics of the system. The simulation results show that magnetizing reactance and rotor resistance is a very important parameter in this control system.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.7
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• pp.656-663
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• 1991

This paper deals with the control strategy for the constant voltage, constant frequency (CVCF) generation of doubly -fed induction generator. Since induction machine is a nonlinear and multivariable one, the influential factors for CVCF generation of induction generator are the magnitude of output voltage, load current and its power factor, slip of the machine, etc. To get appropriate control scheme and study the effect of its parameters, the control equation of induction machine is derived and tested. The simulation and test results show that suggested equation and control system are very useful strategy for the CVCF control of induction generator.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.194-195
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• 2017

본 논문은 독립형 마이크로그리드에서 BESS-디젤발전기 연계운전 시, 동기 인덕턴스와 LCL 필터의 상호간섭을 고려한 CVCF 제어기를 설계하고 해석하였다. CVCF 제어의 외부루프는 비례-공진(PR)을 이용한 기본파 전압제어이고, 내부루프는 제어 안정도 향상을 위한 커패시터 전류제어로 구성된 이중 루프 구조이다. 인버터 $1.5T_s$ 시지연을 고려하여 모델링을 설계하고, 이산시간 영역에서의 근궤적 기법을 통해 CVCF 제어의 안정도를 해석하였다. 50kW BESS-디젤발전기로 구성된 시뮬레이션을 통해 안정도 해석과 동일한 결과를 도출함으로써 설계된 CVCF 제어기를 검증하였다.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.287-290
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• 1999

This paper describes an optimal design method of VSI output filter for CVCF system. The cost function is used for design, and all parameters are described in p.u(per unit) so that can be adapted to the change of CVCF rating. The capacitor current feedback scheme is proposed to control the damping ratio of the filter plant to meet the system more stable. This means that the LC resonance can be suppressed well in transient condition and can use the same control gains under the change of system capacity. The validity of the proposed method is well verified with the theoretical analysis and simulation results.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.2
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• pp.86-93
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• 2018

In this work, control methods and operating modes are proposed to manage standalone microgrid. A standalone microgrid generally consists of two sources, namely, battery energy storage system (BESS) and diesel generator (DG). BESS is the main source that supplies active and reactive power regardless of load conditions, whereas DG functions as an auxiliary power source. BESS operates in a constant voltage constant frequency (CVCF) control, which includes proportional-integral + resonant controller in a parallel structure. In CVCF control, the concept of fundamental positive and negative transformation is utilized to generate a three-phase sinusoidal voltage under imbalanced load condition. Operation modes of a standalone microgrid are divided into three modes, namely, normal, charge, and manual modes. To verify the standalone microgrid along with the proposed control methods, a demonstration site is constructed, which contains 115 kWh lead-acid battery bank, 50 kVA three-phase DC - AC inverter, and 50 kVA DG and controllable loads. In the CVCF control, the total harmonic distortion of output voltage is improved to 1.1% under imbalanced load. This work verifies that the standalone microgrid provides high-quality voltage, and three operation modes are performed from the experimental results.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.379-382
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• 2003

In this paper, a novel nonlinear control method of the CVCF(constant voltage and constant frequency output voltage for the three-phase PWM inverter is proposed, which gives high dynamic responses at load variation as well as zero steady-state error. The experimental results are shown th verify the validity of the proposed scheme.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.548-553
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• 2003

Battery supplies Each Electric device in Railway vehicles with Control Power. When Battery is overchargedjustly, the battery voltage is not satisfied with the minimum operating voltage, CVCF Inverter(SIV) is supplied with external Power supply or the other railway vehicles and start up CVCF Inverter. In this paper to improve this problem, Dead battery Starter system is proposed. When the battery voltage is not satisfied with the minimum value.turn on the Dead Battery Starter switch, and the Dead Battery Starter supplies the control power to the SIV controller from the line voltage. With this Dead Battery Starter system, the train can be operated when the battery is not proper status. Dead Battery Starter is designed by ROTEM and will be delivered to Attiko Metro Series 2.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.5
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• pp.493-500
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• 2000

The battery charger for high speed trail car is very important power source for the purpose of safety and system stability It provides control power of VVVF, CVCF, DC/DC converter and inverter for traction motor. This paper included power circuit of the ZVZCS type battery charger for high speed trail car and battery charging algorithm. Also the optimum parallel operation of 50kW battery charger for high speed trail car, and charring control method of Ni-Cd battery illustrates validity and effectiveness through the experiments.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.267-272
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• 1999

The auxiliary power supply system fur passenger service of railway car has been developed from MA(Motor-Alternator) to CVCF Inverter (Static Inverter). Generally, a customer wants to apply tile new control method and device for auxiliary power supply of railcar However, if the auxiliary power supply is supplied to extended existing line, the maintenance cost of the old system is less expensive than new developed system, so, the customer specifies that the auxiliary power supply has compatibility with existing one completely. At that time, the hardware is nearly same as existing system except small changes of accessories for better performance. This paper describes the flicker control using feed-forward method of auxiliary power supply system for new 50 electric railcars, which are delivered to Korean National Railroad (KNR) Kwa-chon Line. The existing power supply system has damping resistor box to stabilize the DC input (1.5 ㎸). At this time, for better system efficiency the new system has not include resistor box but new control method including feed-forward control is applied. This control algorithm realizes the better stabilization of input power compared to the result of the existing system, which includes resistor box