The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In the last decade there has been a tremendous growth in the number of data centers due to the increasing demand for Internet services. At the same time, the cost for energy and materials have increased because of reducing resources and increased demand. That has caused a change in the driving forces for new power supply development, with more consideration on power density and efficiency. The commonly...
A new interleaved active-clamp forward converter with parallel input and series-parallel output is proposed in this paper. With the proposed topology the secondary windings of the transformers work in series when the input voltage is low but in parallel when the input voltage is high. Therefore, the duty cycle is not limited within 0.5 and the steady state conversion gain of the converter can be improved...
The ZVS-SVM controlled three-phase boost rectifier can realize ZVS operation for all switching devices. In this paper, the operation principal and design guideline are described in detail. The soft switching restriction is analyzed in particular. The experimental results of a 40 kW hardware prototype are presented to show the superiority of the topology and the reduction on loss.
Two techniques are presented to balance the filter capacitor voltages of a multi-pulse rectifier with active injection operating on a variable frequency supply. The active injector consists of a low-rated, bidirectional switch that modifies the behaviour of a 12-pulse rectifier at either low or high-frequency, resulting in 24-pulse or multi-level PWM operation respectively. The operation of the rectifier...
The main goal of this paper is to propose three new three-phase to three-phase ac-dc-ac converters, in which the input side is implemented with three-phase three-level PFC rectifier. This rectifier presents some advantages when compared to the two-level rectifier, i.e.: a) operation with high power level; b) reduced voltage harmonics while operating at lower frequency; and c) better quality in the...
This paper addresses control techniques aimed at improving light-load efficiency and reducing harmonic distortion in digitally controlled single-phase boost power factor correction (PFC) rectifiers. Based on a discontinuous conduction mode (DCM) detection circuit, it is shown how an extension to the predictive current control law leads to improved current regulation over wide load range in both continuous...
Accurate input power measurements for off-line power supplies are required for both time-of-use billing and system power management purposes. When a digitally controlled PFC is utilized at the front end of the power supply much if not all the information necessary to calculate the input power has already been sensed as digital control data. This paper investigates input power measurement techniques...
A novel ZVZCS L2C-Type parallel resonant converter is presented in this paper. This converter, compared with the Type-4 LLC converter, narrows the switching frequency deviation under wide input voltage range applications, while maintaining all soft-switching advantages as ZVS for primary switches and ZCS for output rectifiers, both of which eases design for input EMI filter. In addition, the proposed...
It is well known that there exist second-order harmonic current and corresponding ripple voltage on dc bus for single phase PWM rectifiers. The low frequency harmonic current is normally filtered using a bulk capacitor in the bus which results in low power density. This paper studies the energy storage capacitor reduction methods for single phase rectifiers. The minimum ripple energy storage requirement...
This paper illustrates the rectifier stress issue of the active clamped dual switch forward converters operating on discontinuous current mode (DCM), and analyzes the additional reverse voltage on the rectifier diode of active clamped dual switch forward converter at DCM operation, which does not appear in continuous current mode (CCM). The additional reverse voltage stress, plus its spikes, definitely...
A new interleaved forward converter, adopting series-input structure with a common transformer reset circuit, is proposed in this paper. Series-input structure distributes the switch voltage stress, which makes it suitable for high input voltage applications. Moreover, since two forward converters share one active-clamp circuit for the transformer reset, its primary structure is simplified. In addition,...
The paper presents an innovative off-line low profile converter design that delivers 750 W of power at 95%-96% efficiency for nominal input range, using variable frequency topology with high frequency zero voltage switching (ZVS) and zero current switching (ZCS) for primary switchers. Theoretical considerations and practical results are presented for high frequency and high voltage soft-switching...
This paper proposes a push-pull forward (PPF) three-level (TL) converter, which is suitable for low and wide-range input voltage applications, such as fuel cell power system. Half of the switches sustain half of the input voltage, and the others sustain one and one-half input voltage. Input ripple current and output filter inductor ripple current can be reduced with the TL waveform of the secondary...
Average model of three-phase PWM converters is important in both theory and practical engineering. To remedy defects possessed by the existing average models of three-phase boost rectifiers and voltage source inverters (VSI), this paper proposes and derives another new-formed models that are easy-to-use and more suitable for computer simulation. During establishing switching models, the number of...
In this paper, a new bidirectional three-phase dc-dc converter and three-phase PWM strategies have been proposed for battery application. The proposed converter acts as an three-phase isolated buck converter when battery is charged from dc link (buck mode) and an three-phase isolated boost converter when battery discharges energy (boost mode). In the buck mode, three-phase hybridge rectifier is employed...
The MVAC-SVM controlled three-phase boost rectifier can realize ZVS operation for all switching devices. SVM can be realized with switch device operating at the fixed switching frequency. And the switching voltage stress of all the power switch devices is equal to the DC link voltage. In this paper, a minimum voltage active clamping zero voltage switching SVM controlled three phase boost rectifier...
This paper identifies a new fault type of non-regenerative three-level boost rectifiers (Vienna-type rectifiers), namely the dc-link voltage-doubling fault. Under this failure mode, the voltage across the dc-link capacitors is doubled when any of the ac switches in the neutral path of the converter is shorted, a unique behavior of three-level neutral-point clamped topologies. Addressing this, two...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.