• Journal of the Korean Institute of Telematics and Electronics
• /
• v.27 no.9
• /
• pp.1427-1435
• /
• 1990

This paper proposes the Selected Harmonic Elimination Pluse Width Modulation (SHE PW) scheme toreduce the ahrmonic components of source line current. To eliminate the low order harmonics which affects the source dominatly, we apply the Fourier series analysis to line current waveforms and then find out the switching patterns using the SHE PWM scheme. In addition to the analysis of harmonic effects, the three phase filter circuit is used to reduce high order harmonics. For the experimental realization, the converter circuit with power Transistor(PTR) is designed and the Pulse Time Control(PTC) is applied. The line current and the load voltage are measured under the condition of three phase application, highly inductive load.

• Journal of Power Electronics
• /
• v.12 no.5
• /
• pp.689-698
• /
• 2012

This paper investigates the effects of applying different input current waveshapes on the performance of a continuous-conduction-mode (CCM) power-factor-correction (PFC) boost pre-regulator. It is found that the output voltage ripple of the pre-regulator can be reduced if the input current is modified to include controlled amount of higher order harmonics. This finding allows us to balance the performance of output regulation and the harmonic current emission when coming to the design of the pre-regulator. An experimental PFC boost pre-regulator prototype is constructed to verify the analysis and show the benefit of the pre-regulator operating with input current containing higher order harmonics.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.07b
• /
• pp.1154-1157
• /
• 2004

During normal machine operation, partial discharge(PD) measurements were performed with turbine generator analyzer(TGA) in imitation stator winding of high voltage motors. The motor was energized to 4.47kV, 6.67, respectively. Applied voltage to Imitation winding was used two voltage level, 4.47[KV]and 6.67[KV]. Motors having imitation stator winding were installed with 80pF capacitive couplers at the terminal box Case of PD Pattern regarding applied voltage phase angel, the PD patterns were displayed two dimensional and three dimensional. TGA summarizes each plot with two quantities such as the normalized quantity number(NQN) and the peak PD magnitude(Qm). As the result, we could discrimidate using TGA the difference of internal and surface discharge for imitation stator winding. We have used the other technique, in order to feature extraction of faulty signals on stator winding, Daubechies Discrete wavelet transform and Harmonics analysis(FFT) about faulty signals.

• Proceedings of the KIPE Conference
• /
• 2004.11a
• /
• pp.124-126
• /
• 2004

This paper describes a boost converter cascaded high frequency link direct do-ac converter suitable for fuel cell power sources. A new multi-loop control for a boost converter to reduce the low frequency input current harmonics drawn from fuel cell is proposed. A new PWM technique for the cycloconverter at the secondary to reject the low order harmonics in the output voltages is presented in detail.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2005.11a
• /
• pp.245-249
• /
• 2005

This paper describes a boost converter cascaded high frequency link direct dc-ac converter suitable for fuel cell power sources. A new multi-loop control for a boost converter to reduce the low frequency input current harmonics drawn from fuel cell is proposed. A new PWM technique for the cycloconverter at the secondary to reject the low order harmonics in the output voltages is presented in detail.

• Proceedings of the KIEE Conference
• /
• 1998.11a
• /
• pp.137-140
• /
• 1998

A new SPWM inverter using three-phase boost converter by auxiliary partial resonant with high power factor and high efficiency is proposed. The proposed boost converter is constructed by using a resonant network in parallel with the switch of the conventional boost converter. The devices are switched at zero voltage or zero current eliminating the switching loss. A new Partial resonant boost converter achieves zero-voltage switching (ZVS) or zero-current switching (ZCS) for all switch devices without increasing their voltage and current stresses. This paper introduces elimination of low-order harmonics compared with conventional SPWM inverter and SPWM inverter using three-phase boost converter by auxiliary Partial resonant.

• Proceedings of the Optical Society of Korea Conference
• /
• 2004.07a
• /
• pp.120-121
• /
• 2004

• Proceedings of the Optical Society of Korea Conference
• /
• 2007.02a
• /
• pp.279-280
• /
• 2007

• Proceedings of the Optical Society of Korea Conference
• /
• 2008.02a
• /
• pp.431-432
• /
• 2008

• Journal of the Korean Society for Railway
• /
• v.12 no.6
• /
• pp.989-995
• /
• 2009

Short-time Fourier transforms (STFT) are useful for analyzing signals with harmonics that vary with time. If the variation of the harmonics with time is smooth, such as in kinematic vibrations in vehicles, then it is possible to improve the STFT using order spectra and correlation analysis. In this paper, it is shown how correlation analysis can be performed when the speed signal is noisy or unknown and then it is shown how order spectra become simple to compute after this analysis. The results are illustrated by an analysis of axle and car body vibrations in the prototype high-speed train, HSR-350x.