• Proceedings of the KIPE Conference
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• 2015.11a
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• pp.147-148
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• 2015

This paper presents an odd harmonic repetitive controller for single-phase UPS inverters. The proposed repetitive controller achieves the low output voltage THD and reduces the steady-state error by eliminating odd harmonic distortions caused by nonlinear and unbalanced loads. The proposed control scheme is verified through experiment using a 5kW single-phase T-type inverter.

• Honam Mathematical Journal
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• v.35 no.2
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• pp.137-146
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• 2013

Motivated essentially by their potential for applications in a wide range of mathematical and physical problems, the log-sine and log-cosine integrals have been evaluated, in the existing literature on the subject, in many different ways. The main object of this paper is to present explicit evaluations of some families of log-sine and log-cosine integrals by making use of the familiar Beta function.

• Journal of Power Electronics
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• v.12 no.4
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• pp.654-663
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• 2012

In this paper, a digital control strategy based on equivalent fundamental and odd harmonic resonators is proposed for single-phase DVRs. By using a delay block, which can be equivalent to a bank of resonators, it rejects the fundamental and odd harmonic disturbances effectively. The structure of the single closed-loop control system consists of a delay block, a proportional gain and a set of zero phase notch filters. The principle of the controller design is discussed in detail to ensure the stability of the system. Both the supply voltage and the load current feedforwards are used to improve the response speed and the ability to eliminate disturbances. The proposed controller is simple in terms of its structure and implementation. It has good performances in harmonic compensation and dynamic response. Experimental results from a 2kW DVR prototype confirm the validity of the design procedure and the effectiveness of the control strategy.

• Journal of applied mathematics & informatics
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• v.18 no.1_2
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• pp.377-381
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• 2005

We present a convenient recursive formula for the sums of alternating harmonic series of odd order. The recursion is obtained by expanding in Fourier series certain elementary functions.

• Journal of the Chungcheong Mathematical Society
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• v.26 no.4
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• pp.769-780
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• 2013

Motivated essentially by their potential for applications in a wide range of mathematical and physical problems, the log-sine and log-cosine integrals have been evaluated, in the existing literature on the subject, in many different ways. Very recently, Choi [6] presented explicit evaluations of some families of log-sine and log-cosine integrals by making use of the familiar Beta function. In the present sequel to the investigation [6], we evaluate the log-sine and log-cosine integrals involved in more complicated integrands than those in [6], by also using the Beta function.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1100-1103
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• 2004

The paper presents the results of using the fundamental and the low frequency harmonic components of leakage current to study aging of EPDM insulator for contaminated condition by kaolin. The largeer the leakage current during 200ms, the higher harmonic component at 60hz. The harmonic component at 60hz and the odd order harmonics is increase relation without Kaolin Conent. Arcing on the surface was always associated with distortion in the leakage current; hence the low frequency components of the leakage currnent can be used as a means to evaluate the surface degration. Both the fundamental and 3rd & 5th harmonics increase dry-band activity.

• Journal of IKEEE
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• v.27 no.3
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• pp.319-326
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• 2023

In this paper, simulation and experimental results are presented, including the implementation of a digital controller for robust output voltage control of a single-phase voltage source inverters (VSIs) and total harmonic distortion (T.H.D.v) analysis. Typically, the VSIs uses a proportional integral (PI) controller for the current controller on the inner loop and a proportional resonant (PR) controller for the voltage controller on the outer loop to control the output voltage. However, non-linear loads still produce high-order odd harmonic distortion. Therefore, in this paper, a proportional multiple resonance (PMR) controller with a resonance controller for odd harmonic frequencies is proposed to suppress harmonic distortion. Analyze the frequency response of controllers for VSI plants and design PMR controllers. Through simulation, the total harmonic distortion characteristics of the output voltage are compared and verified when PI and PMR are used as voltage controllers. Both linear and non-linear loading conditions were considered. Finally, the effectiveness of the PMR controller was demonstrated by applying it to a 3kW VSIs prototype.

• Progress in Superconductivity and Cryogenics
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• v.15 no.1
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• pp.51-54
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• 2013

This paper deals with harmonic components of the voltage on high temperature superconducting wire carrying an alternating current. HTS wire is used to manufacture superconducting power applications carrying an alternating current. Typically, international standard, IEC 61788-3 is used for critical current measurement. Thus, it is not ideal that critical current criteria in dc are adapted to superconducting power devices to decide the operating current of the devices. In this paper, we confirmed odd harmonic voltage on HTS wires carrying an AC. The ratio between harmonic components and fundamental component can be significant clues to decide the critical current criteria for HTS wire and its power applications in AC circumstance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.4
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• pp.379-385
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• 2002

In this paper, frequency trifler fur 8 GHz local oscillator was designed and fabricated using MESFET. The third order harmonic was generated by biasing the transistor on A class. The fundamental frequency and the second harmonic were suppressed by using λ$\_$g//2 stub and band pass filter. As results, conversion gain of 2.67 ㏈ at 8.31 GHz, the harmonic suppression of -41.17 ㏈c, the bandwidth of 510 ㎒ were measured.red.

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.4
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• pp.492-498
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• 2017

In this paper, we integrate a divide-by-3 injection-locked frequency divider (ILFD) in CMOS technology with a $0.18-{\mu}m$ BiCMOS process. We propose a self-injection technique that utilizes harmonic conversion to improve the locking range, phase-noise, and input sensitivity simultaneously. The proposed self-injection technique consists of an odd-to-even harmonic converter and a feedback amplifier. This technique offers the advantage of increasing the injection efficiency at even harmonics and thus realizes the low-power implementation of an odd-order division ILFD. The measurement results using the proposed self-injection technique show that the locking range is increased by 47.8% and the phase noise is reduced by 14.7 dBc/Hz at 1-MHz offset frequency with the injection power of -12 dBm. The designed divide-by-3 ILFD occupies $0.048mm^2$ with a power consumption of 18.2-mW from a 1.8-V power supply.