• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.12
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• pp.2150-2156
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• 2007

According as level of industry develops day after day, electricity load system of industry requires high level control, effectiveness and high efficiency. Among supply and control unit of suitable power supply in these load characteristic, inverter systems of constant current regulate is used widely control of lighting and electric heating system. But, problems that power factor deterioration and fast response of control, efficiency, harmonics and etc are still remain. Therefore, in this paper proposed an inverter systems with constant current regulation and power factor correction (PFC) circuit for lighting and beaconing of aerodromes. The effectiveness of the proposed system confirmed through experimental results of 10[kW] power supply system.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.5
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• pp.98-104
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• 2009

In this paper, improved VCO(voltage controlled oscillator) with push-push structure and high impedance-inverter is designed and implemented. Two harmonic oscillators are combined into push-push structure. As a result, the fundamental suppression and the output power have been progressed. For the improved coupling characteristics between hair-pin resonator and two parallel microstrip line using high impedance inverter, the phase noise has been suppressed.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.918-925
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• 2012

This paper proposes a control method for grid-connected inverter systems under unbalanced and distorted grid voltage. The proposed method can reduce the power ripple caused by the unbalanced condition and compensate for the low-order harmonics of the output currents caused by the distortion of grid voltage. To reduce the power ripple, our method replaces the two conventional PI controllers with one PR controllers in the stationary frame. PR controllers can implement selective harmonic compensation without excessive computational requirements; the use of these controllers simplifies the method. Both the simulated and experimental results agree well with the theoretical analysis.

• The Transactions of the Korean Institute of Power Electronics
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• v.2 no.1
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• pp.1-11
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• 1997

In this paper, a novel multivariable state feedback control with feedforward control is proposed to improve control performance of power conversion systems. The targets of the application are three-phase voltage-source PWM converter and inverter system, and current-source PWM converter and inverter system, of which equivalent circuits and models are derived and analyzed. Various simulation results are presented to verify the validity of the proposed scheme.

• Journal of Power Electronics
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• v.16 no.1
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• pp.142-152
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• 2016

Common mode voltage (CMV) generation is a major problem in switching power converter fed induction motor drive systems. CMV is the zero sequence voltage generated due to the switching action of power converters. Even a small magnitude of CMV with a high rate of change may circulate large bearing currents which may damage a machine's bearings and shorten its life. There are several methods of controlling CMV. This paper presents 3-level sinusoidal pulse width modulation based techniques to control the magnitude and rate of change of CMV in multilevel AC-DC-AC drive systems. Simulation and experimental investigations have been presented to validate the performance of proposed technique to control CMV in 3-level neutral point clamped inverter based AC-DC-AC system.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.3 no.2
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• pp.5-10
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• 2004

In this paper, the hybrid-type current controller for inverter TIG systems was implemented and it was shown that the low-current pulse wave forms with high dynamic performance could be obtained. It is not sri easy to obtain the optimum gain tuning of PID controllers in digital PWM control methods. Hybrid control methods which uses automatic tuning techniques after adding fuzzy control methods to traditional PID controllers are chosen to improve the dynamic performance of PID controller's. To demonstrate the practical significance and dynamic performance improvement of the results, some simulation and experimental results are presented.

• Journal of Power Electronics
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• v.18 no.1
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• pp.103-115
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• 2018

Parametric uncertainties and inverter nonlinearity exist in the permanent magnet synchronous motor (PMSM) drive system of electrical vehicles, which may lead to performance degradation or failure, and eventually threaten reliable operation. Therefore, a model-free deadbeat predictive current controller (MFDPCC) for PMSM drive systems is proposed in this study. The data-driven ultra-local model of a surface-mounted PMSM (SMPMSM) drive system that consists of parametric uncertainties and inverter nonlinearity is first established through the input and output data of a SMPMSM drive system. Subsequently, MFDPCC is designed. The performance comparisons and analyses of the proposed MFDPCC, the conventional proportional-integral controller, and the model-based deadbeat predictive current controller for SMPMSM drive systems are implemented via system simulation and experimental tests. Results show the effectiveness and technical advantages of the proposed MFDPCC.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.5
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• pp.627-634
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• 2006

We have proposed the methods how to control the slope of CMOS inverter's characteristic and how to shift it in y axis. We control the MOS transistor threshold voltage for these methods. By observing that two transistors are in saturation region at the center of the CMOS inverter's characteristic, we have presented how to make the characteristic for one pole neuron. The circuit level simulation is used for verifying the proposed method. PSpice(OrCAD Co.) is used for circuit level simulation.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1035-1037
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• 1992

Generally, fuel cell has characteristics of low voltage, large current and voltage variation under load change. Therefore, DC output voltage of fuel cell is too low to convert into AC with high efficiency and good performance. For this reason, fuel cell generating system is composed of DC-DC converter and inverter in cascade. This paper used 2-phase boost DC-DC converter to obtain low distortion waveform and reduce input-output current ripple, and discussed inverter which can be operated in independent drive mode and utility line interface drive mode. Then, the change of modes can be achived smoothly.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.2
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• pp.103-110
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• 2003

With significant development of power electronics technology, the proliferation of nonlinear loads such as static power converters has deteriorated power quality in power transmission and distribution systems. Notably, voltage harmonics resulting from current harmonics produced by the nonlinear loads have become a serious problem in many countries. Many photovoltaic power generation systems installed in building systems have harmonics that are the worst object for distribution systems as a utility interactive system, and it tends to spread out continuously. Proposed and implemented in this paper is a multi-function inverter control strategy that allows a shunt active filter function to the power inverter of the photovoltaic power generation system established on a building system. The effectiveness of the proposed system is demonstrated through the simulation of a hypothetical power system using PSCAD/EMTDC.