Interleaved switching topology for three-phase power-factor correction

Single-switch boost stages, connected between three-phase rectifiers and DC link capacitors, allow good power factor correction when operated in the discontinuous conduction mode. This paper is presented to aid design at all operating levels of this power converter type. For high output power, it is shown that reduced component stress and higher power factor results from the use of interleaved switching topologies. Some experimental results from a laboratory model are presente

Parallel connection of single-switch three-phase power-factor correction converters for interleaved switching

A circuit for the parallel connection of multiple high-frequency three-phase power-factor-correction converters is proposed which enables their input and output current ripple to be interleaved. Such interleaved operation substantially improves the composite power factor, line-current ripple and output-voltage ripple. The improvement is investigated by developing solutions to circuit state equations which allow the high-frequency content of the line current, as well as the low-order line-frequency harmonics, to be computed. Conclusions drawn from the computed results are verified experimentally using a 1 kW, two-stage, interleaved converte

Interleaved switching topology for three-phase power-factor correction

Single-switch boost stages, connected between three-phase rectifiers and DC link capacitors, allow good power factor correction when operated in the discontinuous conduction mode. This paper is presented to aid design at all operating levels of this power converter type. For high output power, it is shown that reduced component stress and higher power factor results from the use of interleaved switching topologies. Some experimental results from a laboratory model are presente

Parallel connection of single-switch three-phase power-factor correction converters for interleaved switching

A circuit for the parallel connection of multiple high-frequency three-phase power-factor-correction converters is proposed which enables their input and output current ripple to be interleaved. Such interleaved operation substantially improves the composite power factor, line-current ripple and output-voltage ripple. The improvement is investigated by developing solutions to circuit state equations which allow the high-frequency content of the line current, as well as the low-order line-frequency harmonics, to be computed. Conclusions drawn from the computed results are verified experimentally using a 1 kW, two-stage, interleaved converte

Voltage Ripple Reduction in Voltage Loop of Voltage Source Converter

In order to achieve a good dynamical response of a full-bridge AC-DC voltage source converters (VSC). The bandwidth of PI controller must be relatively wide. This leads to the voltage ripple produced in the control signal, as known that its ripple frequency has twice of the line frequency and cause the 3rd harmonic of an input current. A Ripple Voltage Estimator (RVE) algorithm and Feed-Forward Compensation (FFC) algorithm are proposed and added to the conventional control. The RVE algorithm estimated the ripple signal to subtract it occurring in the voltage loop. As a result, the 3rd harmonic of the input current can be reduced, and hence the Total Harmonic Distortion of input current (THDi) are improved.  In addition, the FFC algorithm will offer a better dynamical response of output voltage. The performance evaluation was conducted through the simulation and experiment at 110Vrms/50Hz of the input voltage, with a 600 W load and 250 Vdc output voltage. The overall system performances are obtained as follows: the power factor at the full load is higher 0.98, the harmonic distortion at AC input power source of the converter is under control in IEC61000-3-2 class A limit, and the overall efficiency is greater than 85%

Performance Comparison of Ferrite and Nanocrystalline Cores for Medium-Frequency Transformer of Dual Active Bridge DC-DC Converter

This article reports an investigation into ferrite and nanocrystalline materials for the medium-frequency transformer of a dual active bridge DC-DC converter, which plays a key role in the converter’s efficiency and power density. E65 MnZn ferrite cores and toroidal and cut nanocrystalline cores are selected for the construction of 20-kHz transformers. Transformer performance is evaluated with a 1.1-kW (42–54 V)/400 V dual active bridge DC-DC converter with single-phase shift and extended phase shift modulations. The experimental results indicate that the toroidal nanocrystalline transformer had the best performance with an efficiency range of 98.5–99.2% and power density of 12 W/cm3, whereas the cut-core nanocrystalline transformer had an efficiency range of 98.4–99.1% with a power density of 9 W/cm3, and the ferrite transformer had an efficiency range of 97.6–98.8% with a power density of 6 W/cm3. A small mismatch in the circuit parameters is found to cause saturation in the nanocrystalline toroidal core, due to its high permeability. The analytical and experimental results suggest that cut nanocrystalline cores are suitable for the dual active bridge DC-DC converter transformers with switching frequencies up to 100 kHz

Nonlinear single-loop control of the parallel converters for a fuel cell power source used in DC grid applications

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