Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 116 for “"Harmonic Distortion"”.
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Controlling harmonic distortion in power electronics using active power filters
… power conversion and control, but can generate harmonic distortion in the current that is being drawn. Harmonic distortion can have deleterious effects on the power system, degrading power quality, system performance, and efficiency. Active harmonic filters have gained attention due to the …
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Analysis of harmonic distortion in an Integrated Power System for naval applications
This research quantifies the voltage distortion over the broad range of operating conditions experienced by a Naval warship. A steady state model of an Integrated Power System (IPS) was developed in a commercially available power system simulation tool. The system chosen for this study was a …
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Control of Harmonics in 6-Pulse Rectifiers
<p>Harmonics are always present in electrical power systems. Harmonic distortion is harmless as long as its level is within the limit. However, with the recent rapid advancement of power electronics, i.e. non linear loads, the use of the variable speed drives are increasing day by day. Harmonics …
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Analysis and Comparison of Space Vector Modulation Schemes for Three-Leg and Four-Leg Voltage Source Inverters
… with respect to a) switching losses, b) total harmonic distortion, c) peak-to-peak ripple in the line current and d) the ease of digital implementation. The analysis is performed over the entire range of modulation index and for varying load power factors (leading and lagging) under both …
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Power Quality Analysis of a Three-Phase Cycloconverter Under Variable Operating Conditions
… interest are power factor, input current total harmonic distortion (THD), output voltage THD, and efficiency. The scope of the project includes analytical calculations, PSpice simulations, as well as a hardware implementation. The results show that output frequency has minimal effect on power …
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A Novel Arc Welding Power Supply with Improved Power Factor Correction
… power factor to near unity and reducing total harmonic distortion. State space analysis of the proposed circuit showed that the circuit followed a boost-buck input output relationship. Simulation of the circuit was first implemented in LTspice to verify the functionality of the new topology. …
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The application of communication principles to pulse-width modulated inverters
… prior-art techniques of reducing harmonic distortion in pulse-width-modulated inverters is investigated, and it is shown that such techniques are mainly applicable -to constant voltage/constant frequency inverters.<br/><br/>It is shown that the sampling process inherent in existing …
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High performance on-line control of three-phase PWM current-source converters
… limiting, higher reliability, and low ac-voltage harmonic distortion, voltage-source topologies are more widely used. This is in part due to the fact that current-source topologies present the following difficulties: (a) a lack of on-line modulating techniques that satisfy all the constraints of …
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Reactive power support capability of flyback microinverter with pseudo-dc link
… developed to explain underlying issues such as harmonic distortion, and power losses, which can limit the reactive power support capability. A novel current decoupling circuit is proposed to effectively mitigate zero crossing distortion. Simulations and experimental results are provided to …
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Single-switch three-phase zero-current-transition rectifier with power factor correction
… experimental ZCT rectifier with an IGBT; total harmonic distortion below 9% and efficiency above 95% were obtained.
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A methodology for evaluating energy efficient lighting technologies for their performance, power quality and environmental impacts
… of commercial buildings, a small increase in harmonic distortion level in commercial buildings may jeopardize other loads in the building or the loads connected to the same utility bus. As these devices were tested to quantify their energy saving potential, it was found that they can create …
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Control Strategies for High Power Four-Leg Voltage Source Inverters
… stability issues, unbalanced phase voltage, and harmonic distortion. Each of the loading conditions is presented in detail with a proposed control strategy in order to ensure superior inverter performance. Simulation results are presented for a 90 kVA, 400 Hz VSI under challenging loading …
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Computer simulation of finite amplitude standing waves in rigid-walled ducts.
… the amplitudes and phases of the first 255 harmonics. Curves of harmonic distortion as a function of the strength parameter were found to be in excellent agreement with available experimental data, to agree with the Coppens-Sanders perturbation analysis, and to extend the theoretically …
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Design of a novel test bench for induction heating load characterization
… 1-100 kHz frequency range with up to 2 kW power. Harmonic distortion of the inverter is minimized with a novel multilevel topology and modulation scheme, thus allowing near-sinusoidal excitations to be obtained at varying field strengths and frequencies. To demonstration the capabilities of the …
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An improved electronic ballast for the fluorescent lamps
… devices at light load conditions, the high total harmonic distortion (THO) of the line current, and the poor crest factor ( CF) of the lamp current in this circuit make it difficult to manufacture this circuit into a cost-effective ballast product. This thesis analyzes the problems associated with …
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Analysis and Evaluation of Soft-switching Inverter Techniques in Electric Vehicle Applications
… interference (EMI) noise, the total harmonic distortion (THD) and the control complexity. An analysis of the harmonic distortion caused by short pulses is presented and a space vector modulation scheme is proposed to alleviate the effect. To effectively analyze the soft-switching …
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Microcontroller Design of a Bidirectional Three-Level Pulse Width Modulation AC/DC Converter for Vehicle-to-Grid Application
… simulations show the design provides lower total harmonic distortion (THD) and reduced stress to the charger’s components making it a viable charger design for the electric vehicle industry.</p>
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Power system harmonic field measurements PC simulations and standards
… three main objectives: Application of PC based harmonic penetration packages and a comparison of their simulation results. Investigation and comparison of the IEEE, IEC and ESKOM power system harmonic standards. Measurement of harmonics in two industrial networks and the application of the …
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Low-power amplifier chopper stabilization for a digital-to-analog converter
… of this architecture is maintaining amplifier harmonic performance and transient performance. In simulations, chopper stabilization improved signal-to-noise ratio by 11dB while maintaining system level harmonic distortion performance.
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