Papers by Keyword: Single-Phase

Abstract: The harmonic current detection is an essential part for an active power filter (APF). A random harmonic current detection method for single-phase active power filter without the phase locked loop (PLL) is proposed. The detection errors caused by low pass filters are analyzed, and an improved method has been proposed which can increase the detection accuracy and response speed. This method can detect the single order harmonic current and decompose it. Theoretical analysis and simulation results show the validity of the proposed method.

Abstract: This paper designs a single-phase inverter.Battery as a 12V DC input, and output for the 24V,50 HZ standard AC wave. The load is resistive.The power supply adopts the Boost booster and two full-bridge inverter transform. For the control circuit, the preceding Boost converter using tl494 chip control closed-loop feedback and for the inverter part, adopting the 6N137 to finish the optical coupling isolation.Then,through the DSP (TMS320F2812) to complete the output of SPWM modulation.And the modulated SPWM signal can drive chip IR211 conducting the full bridge inverter. Finally, through a low-pass filter output the standard sine AC inverter power.

Abstract: The objective of this work is to study the increase of the convective heat transfer coefficient in the presence of ultrasound waves and, in particular, to find a relationship between the ultrasonic power and the effective pressure of water. The tests have focused on the heat exchange by natural convection, in single-phase conditions, at atmospheric pressure, between a cylinder, heated by means of the Joule effect, and distilled water, with and without the action of ultrasonic waves. The variables involved in the heat exchange have been varied within the range allowed by the experimental apparatus and the convective heat transfer coefficient has been maximized. The specific thermal flow has been chosen in a range compatible with applications in the field of electronics. For the first time the pressure of water at various ultrasonic power levels has been measured, in the vicinity of the cylindrical surface, thanks to the collaboration with the Naval Experimentation and Support Center (CSSN) of the Italian Navy in La Spezia, Italy.

Abstract: The characteristics and the utilization situation of fruit and vegetable wastes (FVW) were analyzed, and a detailed research conducted on FVW treatment process techniques of single-phase and two-phase anaerobic digestion were summarized. Then the advantages and disadvantages between these two processing techniques are reviewed, respectively. Furthermore, future trends in research and development of FVW treatment process technology have also been briefly discussed, which would provide some new ideas for processing FVW.

Abstract: China's current traction net unilateral power supply mode and the existing traction substation connection and phase change connection determine the existence of stationary phase of traction network. Therefore, the application of modern power electronics and microprocessor control technology and the development of cophase power supply technology with independent intellectual property rights are the way to realize the innovation of traction power supply technology, which will achieve a win-win situation for cophase power and electric power development, it has the vital significance.

Abstract: This paper elaborates a method to realize the single phase full bridge inverter digital controller based on DSP TMS320F28027 and gives the design scheme of both its hardware and its software. In accordance with SPWM duty ratio parameter calculated with DSP algorithm, utilizing the EPWM module on DSP, it finally attains the inverting control from direct current signal to sine wave signal. Compared with traditional method, this new method improves the output waveform effectively and shows stable performance.

Abstract: A single-phase oscillating PM alternator is proposed for Free-Piston Stirling Engines. According to its sinusoidal kinetic characteristic, the design principle of this machine is proposed and on this basis, the finite-Element model is built. In the generator mode, the flux linkage, back EMF, voltage harmonics distortion ratio and thrust ripple are deeply analyzed. Due to the significance of the no-load back EMF, some structural parameters, like the permanent magnet thickness, the mover yoke thickness and the width of the tooth, are further optimized. After obtaining the optimal scheme, the electromagnetic performance of this single-phase oscillating PM alternator is investigated.

Abstract: Single-phase BiFeO₃ (BFO) nano-crystallites were successfully synthesized in the temperature range of 500  750 oC by a simple diluted HNO3 sol method. During the crystallization process no intermediate phases were observed. As an example, we studied the electronic structure and thermodynamic stability of the BFO nano-crystallites calcined at 750 oC by X-ray photoelectron spectroscopy (XPS) and differential scanning calorimetry (DSC). The XPS showed that the oxidation state of Fe is Fe3+. The DSC indicated a novel exothermic peak at about 769 oC during cooling, which might be due to Bi2Fe4O9 or some other phases produced in the decomposition of BFO at high temperature.

Abstract: This paper presents a building detection approach based on HSV color space. The method is based on the gray level histogram features, which can separate the housing construction units from complex background. A building damage detection algorithm based on regional statistical information is also proposed in this paper, and a set of performance parameters of feature vector is studied to identify the extent of the housing collapse. The experiments on Haiti post-earthquake images from Google Earth and Yushu post-earthquake images from Internet are discussed in the paper. The experimental results show that proposed approach is effective and feasible.

Abstract: The structural, and dielectric and piezoelectric properties of (1-x)BaTiO3 – x Bi_1/2K_1/2(X_1/3Nb_2/3)O₃ (X=Cu, X=Mg or X=Zn) ceramic were studied. The single perovskite phase was observed when x≤0.5 for X=Cu and Mg and x≤0.2 for X=Zn. As x increased, the dielectric constant peak temperature and piezoelectric properties continuously decreased for X=Mg and Zn. On the other hand, those of X=Cu possessed a local maxima at x=0.7 and the peak temperature was 200°C and the large field piezoelectric constant, d₃₃*, was 94 pC/N.