• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.293-296
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• 2007

본 논문에서는 UPS 기능을 갖는 단상 태양광 발전 시스템을 제안하였다. 제안하는 시스템은 태양광 어레이 (photovoltaic array)에서 최대전력을 얻기 위해 MPPT (maximum power point tracking)를 수행하는 컨버터, 계통전원 상태나 태양광 발전량에 상관없이 부하에 정현파 전압을 공급하는 인버터, 태양광 어레이에서 발전된 잉여전력을 계통으로 전달하거나 부하에 필요한 전력을 dc bus로 공급하는 인버터, 정전시 dc bus에 전력을 공급하는 양방향 컨버터 (bidirectional converter)로 구성된다. 제안하는 시스템은 발전된 전력을 계통으로 전달할 뿐만 아니라, UPS (uninterruptible power supply)기능도 수행하는 시스템으로 계통전압이 불안정하거나 정전시에도 부하에 안정적이고 깨끗한 전압을 항상 공급할 수 있다. 각각의 인버터, 컨버터, 및 양방향 컨버터는 dc bus를 공유하며, dc bus의 전압에 따라 동작상태가 결정이 된다. dc bus중심의 제어는 dc bus전압을 안정적으로 유지시키며, 부하에 걸리는 전압의 변동을 최소로 하고 시스템의 디자인 및 제어를 단순화한다. 모든 알고리즘과 제어기를 하나의 마이크로 컨트롤러로 구현하였고 제안된 시스템의 우수성을 실험을 통해 검증하였다.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.476-481
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• 1998

In this paper, a commutation torque minimization method using parameter observer for a brushless DC motor fed by a voltage source inverter is described. In order to investigate the nature of the commutation torque ripple in trapezoidal brushless DC motor, a new model of the motor is proposed. The optimal drive voltage to minimize the ripple torque is represented as a function of the motor parameters. Therefore, the important parameter is estimated by least-square algorithm.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.552-554
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• 2006

BIPV(Building Integrated PV) system can expect dual effects that reduce expenses for establishment of PV system by adding new function as outer covering material of building expect producing the electricity. But, there are many generation differences according to the exterior environmental facts(solar cell array, design and installation condition of interactive inverter system) Therefore, it is difficult to optimum design. Consequently in advance design system, we experiment 3kW BIPV(Building Integrated PV) generation. We concrete PV system efficient application of variable. BIPV system that is proposed in this paper, was established in Solar Energy research center of Chosun University, composed with system. This research is a basic study for application of building integrated photovoltaic system for building

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.6
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• pp.544-551
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• 2000

In this paper, 3-phase hybrid series active power filter for compensate current harmonics, voltage drop and unbalanced voltage in the network presented. The proposed system is implemented with a space vector modulation voltage source inverter and a high pass filter connected in parallel to the power system. Here the load is six-pulses thyristor rectifier. The phase angle detected in order to generation reference voltage at load terminal is synchronized with the positive sequence component of the unbalanced source by using symmetrical component transformation. The proposed system has an function harmonic isolation between source and load, voltage regulation, and unbalance compensation. Therefore, what the power system is improved quality, the source current is maintained as a nearly sinusoidal waveform and the load voltage is regulated with a rated voltage regardless of the source variation condition. To verify the validity of the proposed compensating system, the computer simulation and experiment are carried out.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.965-968
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• 2003

This paper describes the PWM-VSI controller of three-phase UPS system using stationary reference frame. This controller meets the specification the UPS inverter output voltage even under the unbalanced or nonlinear load. This controller is also constructed with duble control loop of the outer voltage control loop and the inner current control loop. For the fast response of the output voltage control, yhr inner current control loop of the capacitor current os used. To get the good property against overshoot, the If controller us used. The outer voltage controller is designed with P controller and the high gain transfer function is used for the zero steady state error. All control gains of both controller is designed base on the CDM method.

• Proceedings of the KIPE Conference
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• 2003.11a
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• pp.36-40
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• 2003

On analyzing the power circuit of a DVR system, control limitations and control targets are presented for the voltage compensation in DVRs. The control delay in digital controllers increases the dimension of the system transfer function one degree higher which makes the control system more complicate and more unstable. Based on the power stage analysis, a novel controller for the compensation voltages in DVRs is proposed by a feedforward control scheme. Proposed controller works well with the time delay in the digital control system. This paper also proposes a guide line to design the control gain, appropriate output filter parameters and inverter switching frequency for DVRs in digital controllers. Proposed theory is verified by an experimental DVR system with a typical digital controller.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.780-784
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• 1998

A novel active input unbalance voltage compensator with harmonic current compensating capability is proposed and the operating principle of the proposed system is presented in the 3-phase power system. The proposed system performs both the voltage regulation of the load and the compensation of the harmonic currents generated due to nonlinear load such as diode rectifier. The system to compensate unbalanced voltage and hramonic currents is composed of a 3-phase voltage source inverter, LC filter, series transformer and passive devices at the load side of the line. The compensating voltage to regulate the load voltage and to remove the harmonic current components is transmitted to the line by the series transformer. The validity of the line by the series transformer. The validity of the proposed system is proved by the results of computer simulation.

• Journal of Power Electronics
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• v.13 no.4
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• pp.719-728
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• 2013

A novel hybrid active power filter (NHAPF) that can be adopted in high-voltage systems is proposed in this paper. The topological structure and filtering principle of the compensating system is provided and analyzed, respectively. Different controlling strategies are also presented to select the suitable strategy for the compensation system. Based on the selected strategy, the harmonic suppression function is used to analyze the influence of system parameters on the compensating system with MATLAB. Moreover, parameters in the injection branch are designed and analyzed. The performance of the proposed NHAPF in harmonic suppression and reactive power compensation is simulated with PSim. Thereafter, the overall control method is proposed. Simulation analysis and real experiments show that the proposed NHAPF exhibits good harmonic suppression and reactive power compensation. The proposed compensated system is based on the three-phase four-switch inverter, which is inexpensive, and the control method is verified for validity and effectiveness.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.7
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• pp.323-331
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• 2000

Recently Advanced Static Var Compensators(ASVC) or STATic Synchronous COMpesator(STATCOM) has been considered as a next generation reactive power controller. The STATCOM is a voltage source inverter(VSI) based on the static VAr compensator with only small capacitors on the dc side. The main function of the STATCOM is to keep the bus voltage magnitude at the desired value. This paper compared the PAM STATCOM with the PWM STATCOM. The characteristics and the control method of each model is analyzed. And the simulation of STATCOMs based on the above two methods is presented.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.343-346
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• 1987

This paper proposes a novel high-frequency resonant DC/DC converter having PWM(Pulse Width Modulation) inverter control function. The operating characteristics of this converter circuit are discussed from a thereotical point of view and compared with experimental results. The results of operating characteristic analysis are given leading to complete designing data.