1,720,994 research outputs found
Comparison Among Line-Frequency Commutated Rectifiers Complying with IEC 1000-3-2 Standards
No full textComparison among High-Frequency and Line-Frequency Commutated Rectifiers Complying with IEC 61000-3-2 Standards
No full textRetificadores de Alta Qualidade com Comutaçao em alta ou em Baixa Frequencia - Um Estudo Comparativo
No full textRevista da Sociedade BrasThis paper presents an analysis of a threephase
rectifier with high power factor using a SEPIC DCDC
converter operating in continuous conduction mode
(CCM). The structure is particularly simple and robust.
Its main features are: one power processing stage, which
can operate as step-down or step-up converter, lower
harmonic distortion in the line current and natural
isolation. The converter works with constant frequency
and PWM modulation. A study for steady state
conditions, a design procedure, and experimental results
obtained from a laboratory prototype are presented
Interaction between EMI Filter and Power Factor Preregulators with Average Current Control: Analysis and design considerations
No full textThe effects of a nonnegligible source impedance, due to the presence of an input EMI filter, on the stability of power factor preregulators (PFP’s) with average current control are analyzed by using a state-space averaged model. Differently from previous approaches, it allows us to derive a simple expression for the loop gain in terms of the converter current loop gain. The overall system stability was studied for boost, Cuk, and SEPIC PFP topologies. Based on this model, a simple modification of the standard current control loop is proposed which increases the converter robustness against instabilities. Comparison between model forecasts and experimental measurements was carried out using two prototypes, one based on the boost topology and the other based on the SEPIC topology, both rated at 600 W.
Finally, the model accuracy was investigated with measurements
at different current loop bandwidths
A Double-Line-Frequency Commutated Rectifier Complying with IEC 1000-3-2 Standards
No full textThis paper presents a high power factor rectifier, based on a modified conventional rectifier with passive L-C filter, which utilizes a line-frequency-commutated switch and a small auxiliary circuit in order to improve both harmonic content of the input current and power factor, thus allowing compliance with IEC 1000-3-2 standards. With the switch turned on and off only twice per line period, the associated losses are very small. Moreover the limited di/dt and dv/dt considerably reduce the high-frequency noise emission, thus avoiding heavy EMI filters. The switch operation results in a boost action, which compensates for the filter inductor voltage drop, thus providing output voltage stabilization against load variations. Compared with other similar approaches, the presented topology can achieve higher power levels with a reasonable overall magnetic component size
Modeling and Control Design of the Six-Phase Interleaved Double Dual Boost Converter
No full textThis paper presents the small-signal modeling and the control design of the six-phase Interleaved Double Dual Boost, which is a non-insulated, step-up DC-DC converter that can be operated with high voltage gain and can be scaled to high-power applications. The applications of this converter include electrical vehicles and renewable energy conversion. Experimental results obtained with a prototype operating with input voltage of 60V and output voltage of 360V and with nominal output power of 2.2kW are presented
Comparison of non-insulated, high-gain, high-power, step-up DC-DC converters
No full textThis paper compares some topologies of non-insulated, step-up DC-DC converters that are capable of high voltage gain and bidirectional power flow and are suitable to high power applications. This comparison has the objective of selecting the best topology for the proposed scenario, which was based on specifications that are typical in renewable energy conversion and small electric vehicles systems. Experimental results obtained with the selected topology are presented
Modeling and Control Design of the Interleaved Double Dual Boost Converter
No full textThe Interleaved Double Dual Boost is a noninsulated, step-up DC-DC converter capable of high voltage gain and suitable to high-power applications. In this paper, the modeling and control design of this converter, valid for an arbitrary number of phases, is presented. The developed approach is then applied to a six-phase Interleaved Double Dual Boost and experimental results are obtained with a prototype operating with input voltage of 60V, output voltage of 360V and with nominal output power of 2.2kW. The applications of this converter include electrical vehicles and renewable energy conversion
A Single-Phase Low-Frequency Commutation Inverter for Renewables
No full textCo-generation systems integrating distributed low power sources with the utility generally ask for an electronic power converter for conditioning the locally generated power and inject current into the grid. If the source provides a DC voltage, the converter should be able to produce a lowdistortion, high-power factor AC current. For low-power applications, like photovoltaic panels and fuel cells, a singlephase inverter (DC-AC converter) can be used for connecting the source with the grid. The paper describes a single-phase DC-AC topology for interfacing DC sources with the utility. The commutation of the power switches is at the line frequency. The main advantages of the proposed converter are: (1) negligible switching losses – high efficiency; (2) negligible EMI; (3) the current injected into the grid presents low harmonic distortion and high power factor; (4) higher reliability compared to PWM inverters (due to the simpler control circuitry). The power flux can be controlled either by varying the DC voltage or
controlling the switches command
Three-Phase Low-Frequency Commutation Inverter for Renewable Energy Systems
No full textThe connection of distributed power sources with the utility grid generally needs an electronic power converter for processing the locally generated power and injecting current into the system. If the source provides a dc voltage, the converter must be able to produce a low-distortion high-power-factor ac current. The same aspects related with the voltage and current distortion produced by nonlinear loads can be considered for the injection of power into the grid. In the absence of a specific standard, this paper takes as a reference the limits for current harmonics given by international standards. The justification for this approach is that, from the resulting line voltage degradation, there is no difference between injected and absorbed currents. This paper presents a three-phase inverter using low-frequency commutation. An auxiliary circuit is added to the inverter topology
to reduce the output voltage distortion, thus improving the current waveform. The main advantages of this approach are the minimization of the switching losses and the elimination of the
electromagnetic interference, which avoids high-frequency filters
necessary in high-frequency commutation inverters
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