• International Journal of Control, Automation, and Systems
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• v.6 no.5
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• pp.670-676
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• 2008

While the matrix converter has many advantages that include bi-directional power flow, a size reduction, a long lifetime, and sinusoidal input currents, it is vulnerable to the input voltage disturbances, because it directly exchanges the input voltage to the output voltage. So, in this paper, a critical evaluation of the effect of various abnormal voltage conditions like unbalanced power supply, balanced non-sinusoidal power supply, input voltage sags and short time blackout of power supply on matrix converter fed induction motor drives is presented. The operation under various abnormal conditions has been analyzed. For this, a 230V, 250VA three phase to three phase matrix converter (MC) fed induction motor drive prototype is implemented using DSP based controller and tests have been carried out to evaluate and improve the stability of system under typical abnormal conditions. Digital storage oscilloscope & power quality analyzer are used for experimental observations.

• Proceedings of the KIEE Conference
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• summer
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• pp.1205-1207
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• 2004

AC plasma power supply is used to control a ozone generator and a air pollution gas. AC plasma power supply is composed of power semiconductor switch devices and control board adapted SHE(Selected Harmonic Elimination) PWM method. AC plasma power supply with sinusoidal VVVF(variable voltage and variable frequency) is realized. Its output voltage range is from 0 [V] to 20[kV] and output frequency range is from 8[kHz] to 20[kHz]. Using proposed system, AC high voltage and high frequency discharge is tested in the DBD(dieletric barrier discharge) reactor, and the space distribution of a its non-thermal plasma is observed. In spite of the increasement of voltage and frequency, the proposed system have a stable operation characteristics. It is verified by the experimental results.

• Journal of Power Electronics
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• v.5 no.4
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• pp.264-271
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• 2005

A new modified trapezoidal modulating signal for a pulse width modulation (PWM) inverter suitable for a permanent magnet synchronous motor (PMSM) drive is proposed in this paper. A new modulating signal for the PMSM drive is determined by the characteristic torque ripple of the motor with various electro-motive force (EMF). The proposed modulating signal is able to decrease the torque ripple even if the motor has sinusoidal EMF or non-sinusoidal EMF. By using the proposed modulating signal, the system reduced the torque ripple as well as achieved the effective utilization of the DC supply voltage for the inverter. Many improvements are accomplished by the PWM strategy adapting the modified trapezoidal modulating signal without a change in hardware.

• Journal of Power Electronics
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• v.17 no.3
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• pp.777-787
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• 2017

A new single phase half-bridge cascaded multilevel inverter based series active power filter (SAPF) is proposed. The main parts of the inverter are presented in detail. With the proposed inverter topology, any compensation voltage reference can be easily obtained. Therefore, the inverter acts as a harmonic source when the reference is a non-sinusoidal signal. A 31-level inverter based SAPF with the proposed topology, is manufactured and the voltage harmonics of the load connected to the point of common coupling (PCC) are compensated. There is no need for a parallel passive filter (PPF) since the main purpose of the paper is to represent the compensation capability of the SAPF without a PPF. It is aimed to compensate the voltage harmonics of the load fed by a non-sinusoidal supply using the proposed inverter. The validity of the proposed inverter based SAPF is verified by simulation as well as experimental study. The system efficiency is also measured in this study. Both simulation and experimental results show that the proposed multilevel inverter is suitable for SAPF applications.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.7
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• pp.430-436
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• 2004

This paper presents an advanced control technique for power density maximization of the Brushless DC (BLDC) generator by using the linear tracking method. In a generator of given rating, the weight and size of the system affect the fuel consumption directly. Therefore, power density is one of the most important issues in a stand-alone generator. BLDC generator has high power density in the machine point of view and additional increases of power density by control means can be expected. Conventional rectification methods cannot achieve the maximum power possible because of hon-optimal current waveforms. The optimal current waveform to maximize power density and minimize machine size and weight in a nonsinusoidal power supply system has been derived, incorporated in a control system, and verified by simulation and experimental work. A new simple algebraic method has been proposed to accomplish the proposed control without an FFT which is time consuming and complicated.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.207-207
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• 2016

plasma group velocities of neon with oxygen admixture (ug) are obtained by intensified charge coupled device (ICCD) camera images at fixed gate width time of 5 ns. The propagation velocities outside interelectrode region are in the order of 104 m/s.The plasma ambipolar diffusion velocities are calculated to be in the order of 102 m/s. Plasma jet is generated by all fixed sinusoidal power supply, total gas flow and repetition frequency at 3 kV, 800 sccm and 40 kHz, respectively. The amount of oxygen admixture is varied from 0 to 2.75 %. By employing one dimensional convective wave packet model, the electron temperatures in non-thermal atmospheric-pressure plasma jet are estimated to be in a range from 1.65 to 1.95 eV.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.156.1-156.1
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• 2015

Neon and argon plasma group velocities (ug) are obtained by intensified charge coupled device (ICCD) camera images at fixed gate width time of 5 ns. The propagation velocities in upstream and downstream region are in the order of 104-105 m/s. The plasma ambipolar diffusion velocities are calculated to be in the order of 101-102 m/s. Plasma jet is generated by sinusoidal power supply in varying voltages from 1 to 4 kV at repetition frequency of 40 kHz. By employing one dimensional convective wave packet model, the neon and argon electron temperatures in non-thermal atmospheric-pressure plasma jet are estimated to be 1.95 and 1.18 eV, respectively.

• Journal of Power Electronics
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• v.11 no.5
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• pp.677-687
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• 2011

In this paper a cycloconverter-type high frequency transformer link inverter with a reduced switch count is analyzed and designed. The proposed topology consists of an H-bridge inverter at the transformer's primary side and a cycloconverter with three bidirectional switches at the secondary. All of the switches of the cycloconverter operate in non-resonant zero voltage and zero current switching modes. To overcome a high voltage surge problem resulting from the transformer leakage inductance, phase angle control based on natural commutation is employed. The effectiveness of the proposed inverter is verified by constructing s 750W prototype. Experimentally, the inverter is able to supply a near sinusoidal output voltage with a total harmonic distortion of less than 1%. For comparison, a PSpice simulation of the inverter is also carried out. It was found that the experimental results are in very close agreement with the simulation.

• Advances in Computational Design
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• v.2 no.4
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• pp.283-291
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• 2017

High frequency full bridge series resonant inverters have become increasingly popular among power supply designers. One of the most important parameter for a High Frequency Full Bridge Series Resonant Inverter is optimal coil design. The optimal coil designing procedure is not a easy task. This paper deals with the New Approach to Optimal Design Procedure for a Real-time High Frequency Full Bridge Series Resonant Inverter in Induction Heating Equipment devices. A new design to experimental modelling of the physical properties and a practical power input simulation process for the non-sinusoidal input waveform is accepted. The design sensitivity analysis with Levenberg-Marquardt technique is used for the optimal design process. The proposed technique is applied to an Induction Heating Equipment devices model and the result is verified by real-time experiment. The main advantages of this design technique is to achieve more accurate temperature control with a huge amount of power saving.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.361-365
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• 2002

Advancements in silicon phase control (SCR) technologies provide an arc welding power supply that has the capability to allow the alteration of the Alternating Current (AC) welding output. These technologies provide a square wave output involving sixteen frequency selections and multiple balance selections. While an AC out put is known to minimize magnetic disturbances associate with Direct Current (DC), the potentials of a non-sinusoidal waveform have not been explored. The focus of the paper is to determine the effects that the frequency and balance of an AC wave form output will have upon a high speed Submerge Arc (SAW) application. The test matrix of the project includes welding .250" steel plate. Joint type is square groove with a travel speed of 65 IPM. Each of the weld parameters was held constant, only the frequency and/or balance were altered between welds. Each frequency/balance combination involved three-gap spacing. Upon completion of the welds the bead profiles were measured and recorded. A relationships/trends were observed with various frequency and balance values. Optimum frequency and balance values were found for the .250" square groove application which permit consistent weld sizing, ease of slag removal, and minimal plate distortion.