• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.3
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• pp.211-218
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• 2000

The performance and dynamic characteristics of three-phase active power filter with PCC voltage compensation is presented and analyzed in this paper. The characteristics of parallel active filter are discussed when they are applied to nonlinear loads with current source and voltage source type, the characteristics of voltage compensator and comparison of two functions are discussed. The proposed scheme in this paper employs a PWM voltage-source inverter and has two operation modes. First, it operates as a conventional active filter with reactive power compensation while PCC voltage is in a certain range. Second, is operates as a voltage compensator while PCC voltage is out of range. Finally, the validity of this scheme is investigated through analysis of simulation and experimental results for a prototype active power filter system rated at 10KVA.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.10
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• pp.99-105
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• 2010

This paper discussed the theoretical simulation results for developing the blumlein pulsed power source and showed the circuit configuration and the discharge characteristics of the realistic manufactured pulsed power system. In the simulation, the output voltage characteristics at a load resistor showed the general impulse shape when the impedance of a single coaxial cable is matched with the that of a load resistor. In addition, it is confirmed that output values of the pulsed power can be easily controlled by the duplication of coaxial cables and the pulsed waveform showed the general impulse characteristics. Specifically, the inception discharge voltage in the gap distance of 5[mm] between needle and plane electrodes is about 20[kV] and which is lower than about 29[kV] in 9[mm] due to the difference of the reaching time of the inception voltage. Therefore, this paper showed that the output voltage of the blumlein pulsed power source can be easily controlled.

• Journal of Power Electronics
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• v.17 no.6
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• pp.1637-1649
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• 2017

This paper describes an intensive analysis of a harmonic identification algorithm in non-ideal voltages source systems. The dq-axis Fourier with a positive sequence voltage detector (DQFP) is a novel harmonic identification algorithm for active power filters. A compensating current control system based on repetitive control is presented. A design and stability analysis of the proposed current control are also given. The aim of the paper is to achieve a robustness of the harmonic identification in a distorted and unbalanced voltage source. The proposed ideas are supported by a hardware in the loop technique based on a $eZdsp^{TM}$ F28335 and the Simulink program. The obtained results are presented to demonstrate the performance of the harmonic identification and the control strategy for the active power filter in non-ideal systems.

• ETRI Journal
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• v.44 no.5
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• pp.759-768
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• 2022

A novel energy harvesting technique that uses conducted electromagnetic interference as an energy source is presented. Conducted EMI generated from fluorescent light using a switched-mode power supply was measured and modeled as an equivalent voltage source. Two types of rectifier circuits-a bridge rectifier and a voltage doubler-were used as the harvesting devices for conducted EMI source. The matching networks were designed based on the equivalent model, and the harvested power was improved. The implemented energy harvester produces a regulated power over 68.9 mW and current over 15.1 mA while a regulated voltage can be selected between 3.3 V and 5 V. The proposed system shows the highest harvesting power indoor environment and can provide enough power for the Internet of Things devices.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.222-227
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• 1997

Unbalanced source voltages due to unbalanced loads in the 3-phase power system is decomposed into positive, negative and zero sequence components. Also, assuming there is no neutural path in the system, the zero sequence component is not shown. Therefore, it is possible to compensate unbalanced source voltage by canceling the negative sequency component of the voltages of the source. In this paper, an algorithm compensating unbalanced source voltages by canceling the negative sequence component is presented and analysis of instantaneous voltage compensator using 3-phase PWM inverter is carried out through computer simulation.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.684-687
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• 1999

In this paper, a method for controlling a single phase PWM AC/DC converter without any voltage sensors is proposed. In this method, the source voltage is estimated by sliding mode observer and input current is synchronized with the estimated source voltage. The source voltage is estimated by current error between the actul and the estimated current. The experimental results confirm the validity of the proposed control method.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.318-320
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• 2007

Single-phase cycloconverters are widely used for ac-ac power conversion especially for speed control of ac drives. In this paper, a new single-phase to single-phase Z-source cycloconverter topology is proposed. The proposed single-phase Z-source cycloconverter can boost to a desired voltage with various frequency. Thus, it is called a frequency step-down and amplitude voltage step-up converter. The operating principle of the proposed topology is presented. Analysis and simulation for this single-phase Z-source cycloconverter are also presented.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.1
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• pp.35-41
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• 2009

This paper proposes a stand alone type single-phase fuel cells micro-source with a voltage sag compensator for compensating the ac output voltage variations (sag or swell) of micro-source. The proposed micro-source is consist of a PEM(polymer electrolyte membrane) fuel cells simulator, a full bridge de converter, a 60Hz PWM(pulse width modulation) VSI(voltage source inverter), and a voltage sag compensator. Voltage sag compensator is similar to the configuration of hybrid series active power filter, and it is directly connected to micro-source through the injection transformer. Compensation algorithm of a voltage sag compensator adopts a single phase p-q theory. Effectiveness of the proposed the system is verified by the PSIM(power electronics simulation tool) simulation in the steady state and transient state which the proposed system is able to simultaneously compensate the harmonic current and source voltage sag or swell.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.357-358
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• 2015

This paper provides a comparison of power converter loss and thermal description for voltage source and current source type 5MW-class medium voltage topologies of wind turbines. Neutral-point clamped three-level converter is adopted for voltage source type topology while two-level converter is employed for current source type topology considering the popularity in the industry. In order to match the required voltage level of 4160V with the same switching device of IGCT as in voltage source converter, two active switches are connected in series for the case of current source converter. The loss analysis is confirmed through PLECS simulations. In addition, the loss factors due to di/dt and dv/dt snubber and ac input filter are presented. The comparison result shows that VSC-based wind turbine system has a higher efficiency than that of CSC under the rated operating conditions.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.196-199
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• 2001

This paper deals with current harmonics and unbalanced source voltages compensation using combined filter system. Filter system consists of a series active filter and parallel passive filters. Passive filters were a traditional method to compensate current harmonics, so those were installed in power system widely. The active filter can be a substitution to improve filtering characteristics and complement drawbacks of the passive filter. The combined system of the active power filter and passive filter can has a better compensation performances and economical goods. The series type active power filter injects compensation voltage into power system by transformers. It's compensation principle is able to applicate for voltage compensation. A new control algorithm for series active filter to compensate current harmonics and unbalanced source voltages is proposed. In the proposed algorithm, a compensation voltage for harmonic reduction is calculated directly by instantaneous reactive power theory, and a compensation voltage for unbalanced source voltage is calculated in based on a synchronous reference frame. By experiments, we show validity of proposed compensation method.