• Journal of Power Electronics
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• v.19 no.6
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• pp.1515-1526
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• 2019

Ear-piercing high-frequency noise from electromagnetic vibrations in motors has become unacceptable in sensitive environments, due to the application of pulse width modulation (PWM) and in consideration of switching losses. This paper proposed a synchronous periodic frequency modulation (SPFM) method based on the interleaving technique for paralleled three-phase voltage source inverters (VSIs) to eliminate PWM vibration noise. The proposed SPFM technique is able to effectively remove unpleasant high-frequency vibration noise as well as acoustic noise more effectively than the conventional periodic carrier frequency modulation (PCFM) and interleaving technique. It completely eliminates the vibration noise near odd-order carrier frequencies and reduces the PWM vibration noise near even-order carrier frequencies depending on the switching frequency variation range. Furthermore, the SPFM method is simple to implement and does not employ additional circuits in the drive system. Finally, the effectiveness of the proposed method has been confirmed by detailed experimental results.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.1
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• pp.59-65
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• 2014

To obtain an elliptical trajectory at the cutting edge during elliptical vibration cutting, sinusoidal voltage excitations of two piezoelectric actuators have commonly been used. In this study, PWM excitation, which is relatively simple to generate, was employed and its characteristics were investigated. In experimental and analytical analyses, we found that for PWM excitation, the integer-multiple frequencies of the excitation voltage distorted the shape of the elliptical trajectory, whereas at a duty ratio(DR) of 50%, the distortion of the elliptical trajectory was minimized due to disappearance of the first overtone. When the magnitude of the maximum excitation voltage was maintained at the same level for both PWM and sinusoidal excitation, PWM (DR=50%) excitation produced a greater vibration amplitude than sinusoidal excitation but resulted in more rapid saturation of a high-frequency power amplifier.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.905-915
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• 2015

Two PWM techniques using space vector pulse-width modulation (SVPWM) are proposed for a two-phase permanent magnet synchronous motor (PMSM) driven by a two-phase eight-switch inverter. A two-phase motor with two symmetric stator windings is usually driven by a two-phase four-, six-, or eight-switch inverter. Compared with a four- and six-switch inverter, a two-phase eight-switch inverter can achieve larger power output. For two-phase motor drives, the SVPWM technique achieves more efficient DC bus voltage utilization and less harmonic distortion of the output voltage. For a two-phase PMSM fed by a two-phase eight-switch inverter under a normal SVPWM scheme, each of the eight PWM trigger signals for the inverter have to be changed twice in a cycle, causing a higher PWM frequency. Based on the normal SVPWM scheme, two effective SVPWM schemes are investigated in order to reduce the PWM frequency by rearranging four comparison values, while achieving the same function as the normal PWM scheme. A detailed explanation of the normal and two proposed SVPWM schemes is illustrated in the paper. The experimental results demonstrate that the proposed schemes achieve a better steady performance with lower switching losses compared with the normal scheme.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.10
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• pp.97-103
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• 2008

Recently, it is increased to apply sensorless drive for BLDC (Brushless DC) motor to household electrical appliances, especially in the refrigerators and air conditioners, to reduce the cost and the acoustic noise by the operation and to make their functions more comfortable for human beings. In this paper, low-cost sensorless drive for BLDE motor is implemented by random PWM (Pulse Width Modulation). The experimental results show that the electromagnetic noise was reduced and the sound quality was improved by BLDC motor sensorless random PWM Control.

• Journal of Power Electronics
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• v.7 no.3
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• pp.246-256
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• 2007

In this paper, a novel type auxiliary active edge resonant snubber assisted zero current soft switching pulse modulation Single-Ended Push Pull (SEPP) series load resonant inverter using IGBT power modules is proposed for cost effective consumer high-frequency induction heating (IH) appliances. Its operating principle in steady state is described by using each switching mode's equivalent operating circuits. The new multi resonant high-frequency inverter with series load resonance and edge resonance can regulate its high frequency output power under a condition of a constant frequency zero current soft switching (ZCS) commutation principle on the basis of the asymmetrical pulse width modulation (PWM) control scheme. Brand-new consumer IH products using the proposed ZCS-PWM series load resonant SEPP high-frequency inverter using IGBTs is evaluated and discussed as compared with conventional high-frequency inverters on the basis of experimental results. In order to extend ZCS operation ranges under a low power setting PWM as well as to improve efficiency, the high frequency pulse density modulation (PDM) strategy is demonstrated for high frequency multi-resonant inverters. Its practical effectiveness is substantially proved from an application point of view.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.10
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• pp.872-880
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• 2017

Usually, on/off control method is a way to control the thruster. Bang-Bang Control, PWM(Pulse Width Modulator) and PWPF(Pulse Width Pulse Frequency) are widely used as a typical way. When we are designing PWPF, the incorrectly designed parameters($K_m$, ${\tau}$, $U_{on}$, $U_{off}$, $U_m$) make trouble, such as the phase lag, the wasted fuel, the reduced system life. Therefore, the effect of parameters on the system performance should be analyzed before the proper parameters are selected. In this paper, we suggest the PWPF parameters design method by performing a static analysis, and analyze the interactive effects on design parameters by performing a dynamic analysis and simulation.

• Journal of IKEEE
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• v.19 no.1
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• pp.73-79
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• 2015

In this paper, maximum boost space vector pulse-width modulation(MBSVPWM) strategy of Z-Source Inverters(ZSIs) is proposed. Conventional space vector pulse-width modulation(SVPWM) method of Voltage Source Inverters(VSIs) is modified to produce unique PWM patterns that realize the maximum boost control of ZSIs. This proposed method minimizes the switching power losses of ZSIs by reducing the numbers of the shoot-through states. Moreover, some switches keep ON state and the switching transitions do not occur during the specific sectors. An experimental system has been built and tested to verify the effectiveness of the proposed strategy.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05c
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• pp.31-35
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• 2004

We propose driving method of Ultraviolet sensor for fire alarms using pulse width modulation that used to fire detector with sensor of private-use detectable light energy as ultraviolet in energy of electromagnetic-wave type radiate from flame, when combustible burn with contain carbon,. Ultraviolet sensor is UV Tron using gas multiplication effect to current discharge and photoelectric effect of metal. To have high sensibility and to gain proper output voltage, it has high responsive performance. This research designed driving circuit with UV sensors and proposed method of false alarm reduced to resemble fire. the result propers the prevention and extinction of fire technique degree, certificated operation of detector.

• Journal of Power Electronics
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• v.16 no.2
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• pp.473-479
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• 2016

In this paper, the PSC PWM method is chosen as the optimal modulation method for a 20MW VSC HVDC, with consideration of the harmonic distortion of the output voltage, the switching frequency, and the control implementation difficulty. In addition, a new PSC PWM method is proposed in order to achieve an easy application and to solve the redundant control problems encountered in the previous PSC PWM method. To verify the proposed PSC PWM method, PSCAD/EMTDC simulations for an 11-level MMC RTDS HILS test and an 11-level MMC prototype converter test were performed. As can be seen from the results of these tests, the proposed PSC PWM method shows good results in an 11-level MMC with redundant sub-modules.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.4
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• pp.502-509
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• 2013

It presents an efficient switching pattern, which expects a reduction of switching losses in a cascaded H-bridge PWM multilevel inverter. By the proposed switching scheme, the lower H-bridge module operates at low frequency of 60[Hz] because it assigns to transfer most load power. The upper H-bridge module operates at high frequency of PWM switching to improve THD of output voltage. The proposed switching pattern applies to cascaded H-bridge multilevel inverter with PD, APOD, bipolar, and unipolar switching methods. By computer-aided simulations, we verify the validity of the proposed switching scheme. Finally, we prove that the proposed PD and APOD switching patterns are better than those of the conventional one in efficiency.