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Abstract This paper proposes a new single‐phase direct step‐up ac–ac converter by modifying the p‐type impedance source. It provides a high boost factor as well as high efficiency, while only six parts are required to design i...
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Abstract This paper proposes a new single‐phase direct step‐up ac–ac converter by modifying the p‐type impedance source. It provides a high boost factor as well as high efficiency, while only six parts are required to design it, involving just two bidirectional power switches. A safe commutation method has been applied to power switches to make the converter snubber‐free and high efficient. Input and output harmonic filters are no longer required since input and output currents variate continuously with small ripple and low total harmonic distortion (THD). The proposed topology only modulates the output voltage amplitude, not the phase and frequency, so the output frequency is identical to the input frequency and constant. Thus, it can be utilized in step‐up conversion applications, like inductive power transmission from low ac voltage sources. Input and output have the same ground, which is a good protective feature. In this paper, the operating principle of the converter is demonstrated. Experimental results have been represented to evaluate the performance of the converter. For this purpose, an experimental prototype has been fabricated. Results are investigated and compared with other previous step‐up ac–ac converters. Results confirm the theory, operating principle, and performance of the converter.
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The aim of this article is to present the results of the implementation of a simple generic load simulator using pulse-width modulation inverters. The implementation of this load simulator took place at Universidade Federal de Ita...
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The aim of this article is to present the results of the implementation of a simple generic load simulator using pulse-width modulation inverters. The implementation of this load simulator took place at Universidade Federal de Itajuba's electrical drives laboratory. Different types of load can be simulated to evaluate the performance of electric motors in electrical drives. The implemented system shows satisfactory results, even at low speeds. The system arrangement utilizes two pulse-width modulation inverters (one for the motor and the other for the generator), a PC microcomputer, and a data acquisition board installed in a free slot of the microcomputer. A tachogenerator is also used to provide an analog speed signal as well as LabVIEW data acquisition (Hungary) for filtering speed and torque signals for better visualization and interpretation of the results. The torque signal is originated from the motor pulse-width modulation inverter torque transducer.
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This paper describes the performance and loss analysis of a three-port AC/DC/AC three-phase power converter based on the Japanese 10-15 mode vehicle driving pattern. The structure of the proposed circuit consists primarily of an i...
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This paper describes the performance and loss analysis of a three-port AC/DC/AC three-phase power converter based on the Japanese 10-15 mode vehicle driving pattern. The structure of the proposed circuit consists primarily of an indirect matrix converter (IMC) and a boost converter connected to the neutral point of the induction motor. The first part of this paper discusses a method for the optimization of the boost converter during single pulse modulation. The authors propose the implementation of feedforward compensation in the boost converter to suppress the battery ripple. Results show that the battery ripple is reduced by approximately 72% during single pulse modulation. The second part of this paper illustrates the behavior of the proposed converter when simulated under the Japanese 10-15 mode driving pattern. Converter losses under different conditions and circumstances are studied, and on the basis of the results, the optimal point of the power control for the converter is discussed.
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The Active Constellation Extension (ACE) based on clipping technique is a lossless, simple and attractive Peak-to-Average Power Ratio (PAPR) reduction technique. But, when the target clipping level is set below an unknown initial ...
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The Active Constellation Extension (ACE) based on clipping technique is a lossless, simple and attractive Peak-to-Average Power Ratio (PAPR) reduction technique. But, when the target clipping level is set below an unknown initial optimum value, we observe it cannot achieve the minimum PAPR reduction. To overcome the shortcoming of low clipping ratio problem, a novel ACE algorithm with adaptive clipping control is proposed in this paper. First, an adaptive strategy is used to control the size of clipping level 'A'. Secondly, a novel step factor μ considering the possible overlap is adopted, to complete iterative computations in order to increase the convergence speed. Simulation results verify that the modified algorithm has reduced the PAPR and improved the convergence speed significantly without side information and without any extra processing at the receiver end.
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The state of art in alternating current (AC)-induced corrosion in pipelines is reviewed. Growing pipeline networks and their co-location with high-voltage (HV) transmission networks have brought into focus the issue of induced AC ...
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The state of art in alternating current (AC)-induced corrosion in pipelines is reviewed. Growing pipeline networks and their co-location with high-voltage (HV) transmission networks have brought into focus the issue of induced AC corrosion on the pipeline networks. Induced AC corrosion may quickly and severely affect the integrity of pipeline networks, especially considering that a number of such pipelines are transporting huge quantities of hazardous fluids. Any breach in pipeline integrity due to AC corrosion may result in disastrous consequences. In the last 30 years, it has been established that the induced AC corrosion can affect the buried pipeline integrity severely. During operations, the resistive as well as inductive coupling with transmission lines pose a significant risk of pipeline corrosion. The literature is reviewed to put together various issues and factors responsible for AC-induced corrosion in pipelines. The various publications on induced AC corrosion are reviewed to identify characteristics of AC-induced corrosion and major factors that determine the severity and impact of AC-induced corrosion. The areas have been identified wherein scope exists for additional studies on AC corrosion.
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This paper presents a new and simple method for sensorless control of matrix converter drives using a power flowing to the motor. The proposed control algorithm is based on controlling the instantaneous real and imaginary powers i...
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This paper presents a new and simple method for sensorless control of matrix converter drives using a power flowing to the motor. The proposed control algorithm is based on controlling the instantaneous real and imaginary powers into the induction motor. To improve low-speed sensorless performance, the nonlinearities of a matrix converter drive such as commutation delays, turn-on and turn- off times of switching devices, and on -state switching device voltage drop are modeled using a PQ power transformation and compensated using a reference power control scheme. The proposed sensorless control method is applied for the induction motor drive using a 3 kW matrix converter system. Experimental results are shown to illustrate the feasibility of the proposed strategy.
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Activated carbon (AC) is widely used for adsorbent and supporter of catalyst owing to its efficient adsorption capacity and large specific surface area. The objective of this study is to investigate chlorine adsorption properties ...
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Activated carbon (AC) is widely used for adsorbent and supporter of catalyst owing to its efficient adsorption capacity and large specific surface area. The objective of this study is to investigate chlorine adsorption properties of Cu/AC, Ag/AC and Pd/AC, which were prepared by impregnation method. The samples were characterized by X-ray diffraction and Fourier transform infrared spectroscopy techniques. The experimental data showed the loading of copper, silver and palladium could significantly improve the adsorption capacity of activated carbon for chlorine. The maximal adsorption of Cu/AC with 5 wt. % copper content could reach 32.73 % at 30 °C under 0.22 MPa. While the adsorption capacity of 9 wt. % Ag/AC and 9 wt. % Pd/AC are larger, of which the values were 33.46 and 34 %, respectively. Moreover, the structural framework of Cu/AC, Ag/AC and Pd/AC still existed and its adsorption ability remained stable after absorbing continuously for several times.
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Renin-angiotensin system is mainly known as a regulator of cardiovascular homeostasis. The aim of the present study was to determine the immunohistochemical expression of angiotensin-converting enzyme and angiotensin-converting en...
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Renin-angiotensin system is mainly known as a regulator of cardiovascular homeostasis. The aim of the present study was to determine the immunohistochemical expression of angiotensin-converting enzyme and angiotensin-converting enzyme 2 in non-tumorous breast tissue and in G1, G2 and G3 invasive ductal carcinomas, using immunoperoxidase method on formalin fixed paraffin embedded tissue sections from 10 samples of non-tumorous breast tissue and 30 cases of invasive ductal carcinoma. It was found that ACE was located only in ductal epithelium, while in invasive carcinomas, stromal cells were also positive for ACE. Intensity of staining increased with tumour grade. None of the examined invasive carcinomas showed positive staining for ACE2 in tumour epithelial cells, but weak staining was observed in stromal cells adjacent to tumour epithelial cells. In higher grade tumours, less stromal cells were positive for ACE2. These observations suggest that ACE and ACE2 may be involved in the pathogenesis of breast cancer.
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