Search Results (3)

This paper presents a new power delivery architecture to bring AC distribution voltages to core levels for computing loads using only two conversion stages with new converter topologies to potentially replace the traditional four-stage structure in the development of new data centers. This paper also includes new converters as solutions to the proposed two stages. A new switched capacitor (SC)-based AC-DC converter is proposed for the first stage and demonstrated for an intermediate bus with 90 V–110 VAC to 48–60 VDC conversion and power factor correction. The second stage also includes an SC-based hybrid converter with multi-phase operation suitable for power delivery for core voltages of up to ~1 V with a high current density. This work also reports a new phase sequence for the second stage for an extended output voltage range. Individually, the first stage was measured at 96.1% peak efficiency for output currents ranging from 0 to 4.5 A, while the second stage achieved 90.7% peak efficiency with a load range of 0–220 A at 1V. The measured peak power densities were 73 W/in³ for the first stage and 2020 W/in³ for the second stage. In combination, the direct conversion from ~110 VAC to 1 VDC led to a peak efficiency of 84.1% at 50 A, and this setup has been tested with output currents of up to 160 A, where the efficiency was 73.5%. Full article

A novel unidirectional hybrid PFC rectifier topology based on SEPIC and boost converters is proposed, which is applicable to various industrial applications such as electric vehicle charging stations, variable speed AC drives, and energy storage systems. Compared to other rectifiers, the proposed SEPIC-boost-based rectifier exhibits continuous current on the AC side, lower voltage stress on the active switches, a wider range of DC output voltage, no auxiliary DC-DC converters, and a high step-up static voltage gain operating with low input voltage and a low step-up static gain for the high-input-voltage operation. These traits allow the SEPIC-boost-based rectifier to utilize smaller input-side harmonic filtering inductors and adopt active switches with lower voltage ratings, resulting in reduced conduction losses. Additionally, the proposed rectifier features power factor correction and high boost/buck voltage-gain capabilities, simplifying control for electric vehicle charging and expanding its range of applications. In this paper, the operating principle of the novel topology is presented first, and then the mathematical model of the proposed rectifier is built. Based on this, the comparison between the proposed topology and conventional boost and SEPIC converters is given. Furthermore, the control strategy, including the high-power-factor control and the balancing control to the DC capacitor voltages, is discussed. Finally, to validate the accuracy of the proposed rectifier’s theoretical research, a 500-W SEPIC-boost rectifier system has been constructed in the laboratory, generating a 200/120 V_dc output voltage from a 155 V_pk/50 Hz power source. Full article

This research work deals with a hybrid control system based integrated Cuk converter fed brushless DC motor (BLDCM) for power factor correction. In this work, moth-flame optimization (MFO) and a fuzzy logic controller (FLC) have been combined and a moth-flame fuzzy logic controller (MFOFLC) has been proposed. Firstly, the BLDC motor modeling is composed with the power factor correction (PFC) based integrated Cuk converter and BLDC speed is regulated using variable DC-Link inverter voltage which results in a low switching operation with fewer switched losses. Here, with the use of a switched inductor, the task and execution of the proposed converter is redesigned. The DBR (diode bridge rectifier) trailed by a proposed PFC based integrated Cuk converter operates in discontinuous inductor conduction mode (DICM) for achievement of better power factor. MFO is exhibited for gathering of a dataset from the input voltage signal. At that point, separated datasets are sent to the FLC to improve the updating function and minimization of torque ripple. However, our main objective is to assess adequacy of the proposed method, but the power factor broke down. The execution of the proposed control methodology is executed in the MATLAB/Simulink working platform and the display is assessed with the existing techniques. Full article