• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.126-131
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• 2001

This paper deals with implementation of inverter systems for DC power regeneration, which can regenerate the excessive DC power from DC bus line to AC supply in substations for traction systems. From the viewpoint of both power capacity and switching losses, a three-phase square-wave inverter system is adopted. To control the regenerated power, the magnitude and phase of fundamental output voltages should be appropriately controlled in spite of the variation of input DC voltage. Inverters are operated with modified a-conduction mode to fix the potential of each arm. The overall system consists of the line-to-line voltage and line current sensors, an actual power calculator using d-q transformation method, a complex power controller with PI control scheme, a gating signal generator for modified $\alpha-conduction\;mode\;with\;\delta\;and\;\alpha$, a DPLL for frequency followup, and power circuit.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.151-154
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• 2004

To use the SLIM for servo system, the exact account of thrust about the initial speed is needed, but analyzing by equivalent circuit analyzing methode such as rotary induction motor, the error occurs because of the end effect. So, we applied the equivalent circuit considering the end effect of SLIM in this paper. The current control system is advanced the space vector pulse width modulation by using high arithmetic performance microprocessor such as DSP. In this paper, we use the dynamic characteristic analyzing methode that can calculate efficiently the end effect by using equivalent circuit methode in the operating SLIM system modeling and examine the output characteristics of SVPWM with PI controller.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.250-252
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• 2008

An inductor-capacitor-inductor (LCL) filter are widely adapted in grid-connected inverter applications. In this paper, the harmonic attenuations of the LCL filter are quantitatively analyzed, and then the design optimization of two inductance values, which are related on a cost and a size, is illustrated. Based on the design optimization, the LCL filter employing a Symmetric Geometry is proposed. Through the equivalent circuit analysis of the proposed LCL filter, the operating characteristics and validity are presented in detail. In addition, simple proportional-integral (PI) current controller suitable for the LCL Filter is designed to mitigate the resonance problem. From simulation results, it is seen that the proposed LCL filter and control method have a sufficient attenuation and stability for the high frequency distortions and load variations.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.107-108
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• 2012

This paper presents design and implementation of the LDC(1.8 kW DC-DC Converter for Electric Vehicles). For Implementation of the LDC, the adapted topology is ZVS(Zero Voltage Switching) PSFB(Phase Shift Full Bridge) with Digital Control is adopted. Also, for the purpose of stable operation of the LDC in vehicle with variable electrical load condition, Continuous Voltage and Current Limit Control scheme based on PI controller are developed. According to real-car test mode, the prototype of proposed the LDC is verified with performance and stability. Thus, optimizing design and implement of the LDC are discussed, and experimental results are presented.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1282-1286
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• 1999

This paper presents the DQ transfomation and space vector modulation method to develop a control algorithm of distribution STATCON(STATic CONdenser) for line voltage regulation, dc link voltage regulation and harmonics compensation. The Performance analysis of a PI with ramp comparision and synchronous reference frame current controller is carried out. Based on these analysis, the control performances are desirable to compensate the harmonics and to regulate de link and line voltage of Distribution line.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.12
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• pp.113-121
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• 1996

This paper presents a 37.5kVA (125kVp, 300mA) high frequency inverter type power supply for diagonostic X-ray generator with two HFHV (high-frequency high-voltage) isolating transformers. The output regulations, X-ray tuve voltage and tube current, are obtained by two high frequency inverters with the each other feedback PI controller and operating time switch for selecting shooting time and synchronizing two inverters. The operating modes and design consideration of the proposed power supply are given. Issues in the design of two HFHV isolating transformersfors high volage genrating and filament heating are discussed. Experimental results are presented to verify the performance of the designed power supply for varying load conditions. The proposed apparatus has several advnatages, e.g., the fast rising time of tube voltae, accuracy and reduced component size etc.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.196-203
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• 2010

2DOF is applied to induction moor in order to supply these weak points of PI torque control method in this paper. and The proposed method utilize the combination of the voltage model based on stator equivalent model and the current model based on rotor equivalent model, which enables stable estimation of rotor flux. To prove the propriety of this paper, the various simulations carried out adequacy and stability using Matlab, and at the same time real system is made, so it is proved. As the results of embodying the system, the robust system is realized.

• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.194-196
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• 2008

이 논문에서는 연료전지용 3상 전류형 능동 클램프 DC/DC 컨버터의 기동 방법을 제안하고, 정상상태에서 컨버터의 출력 전압 및 입력 전류 제어기를 설계하였다. 3상 전류형 능동 클램프 DC/DC 컨버터는 가동시 클램프 전압과 출력 전압의 차로 인해 스위치 및 변압기 전선에 큰 단락 전류가 흐르는 단점이 있다. 그러므로 가동시 입력 인덕터에 2차 권선을 감아 플라이백방식을 이용하여 출력 전압을 확립시키는 방법을 제안하였다. 정상 상태에서 출력 전압 및 입력 전류 제어를 위해 두 개의 종속 연결 PI 제어기를 설계하였다. 전압 제어 이득의 시정수가 전류 제어 이득의 시정수보다 크게 함으로써 제어기의 안정도를 향상시켰다. 시뮬레이션을 통해 기동 방법을 확인하였다. 500w급 컨버터를 제작하였고, 실험을 통해 설계한 제어기의 성능을 확인하였다.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.196-199
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• 2002

본 논문에서는 유도전동기 벡터제어를 위한 전류 및 속도제어기의 간단한 설계 방법을 제 한다. 일반적으로 유도전동기 전류 및 속도제어에 PI형태의 제어기를 사용할 경우 제어기이득 결정과정에는 많은 시행착오가 따른다. 본 논문에서는 전동기 상수 및 원하는 대역폭으로부터 제어기이득을 직접 구하여 설계과정을 단순화함으로써 시행착오를 줄이거나 제거할 수 있게 하였다. 제안한 방법의 유용성 및 성능을 모의실험을 통해서 확인한다

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.336-339
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• 2005

This paper presents a PM type BLDC(Brushless DC) Motor servo drive system using high performance DSP TMS320F2812. The DSP controller with 150MIPS enables an enhanced real time implementation and increased efficiency and high performance for motor drive. The suggested drive system consists of PI action for the constant speed control and PID action for the current control with only 3 Halls, no encoders. The developed servo drive control system shows a good response speed characteristics at high speed up to 10000 [rpm].