A Multiphase Series-Capacitor Buck Converter with Reduced Flying Capacitor Volume and Auxiliary Start-Up Circuit

Roberts, G.W.; McRae, Timothy; Prodić, Aleksandar

doi:10.23919/epe.2019.8915225

Cited by 6 publications

(5 citation statements)

References 19 publications

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“…To maintain ZVS for the entire load range, the turn-off current Ioff1 should equal -Ioff2, and the angle 𝜑 should be 180 o . The switching frequency 𝑓 𝑠𝑤 equals 1 1+2𝑓 𝑟 𝑇 𝑍𝑉𝑆 𝑓 𝑟 ≈ 𝑓 𝑟 according to (7) and (12). For certain highcurrent applications, a non-ZVS operation with a lower RMS current maybe more preferred than the ZVS operation, and the switching frequency is then higher than fr, corresponding to angle 𝜑 < 180 o .…”

Section: State-plane Analysis Of a 2-to-1 Rescmentioning

confidence: 99%

“…Thanks to the soft-charging and soft-switching features as well as the capacitor's intrinsic advantage of high energy density, the hybrid SC converters have potential to achieve high efficiency and power density simultaneously, and are attracting a lot of interest in recent years. They have demonstrated high performance in fully integrated solutions [5]- [8], as well as in large step-down applications such as 48 V to Point-of-Load (PoL) applications [9]- [12], and wide input range converters [13]- [15].…”

Section: Introductionmentioning

confidence: 99%

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Geometrical State-Plane Analysis of Resonant Switched-Capacitor Converters: Demonstration on the Cascaded Multiresonant Converter

Pilawa-Podgurski

2023

IEEE Trans. Power Electron.

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To realize high efficiency and high power density for resonant switched capacitor (ReSC) converters, it is critical to have a thorough understanding of the soft-switching mechanism and design the converter appropriately. However, this can be challenging as the soft-switching operation depends on multiple variables and its design difficulty increases quickly with respect to the topology complexity. This paper demonstrates a framework of using geometrical state-plane analysis to facilitate ReSC converter design. The methodology is first applied to a basic 2-to-1 ReSC converter, and then extended to a new 4-to-1 ReSC converter topology we proposed, herein named cascaded multi-resonant converter. This topology has reduced component count thanks to a new "switching bus" architecture. However, it comes at a cost as the converter has multiple resonances within each switching cycle, complicating the soft-switching design. Despite the high circuit complexity, the state-plane analysis neatly provides analytical equations of all state parameters, which are verified by simulations and experiments. Our hardware prototype achieves 6000 W/in 3 power density at 48-to-12 V conversion and 80 A continuous output. Its peak efficiency reaches 99.02%, and full-load efficiency reaches 97.67%, including gate drive loss. Both the power density and efficiency are superior to the state-of-the-art 48-to-12 V solutions.

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Section: State-plane Analysis Of a 2-to-1 Rescmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Geometrical State-Plane Analysis of Resonant Switched-Capacitor Converters: Demonstration on the Cascaded Multiresonant Converter

Pilawa-Podgurski

2023

IEEE Trans. Power Electron.

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“…Also, since the switch voltage stress is equivalent to the input voltage, transistors and diodes with high breakdown voltage are selected, leading to extended conduction losses due to the high on‐resistance ( R DSon ) of MOSFETs and high forward voltage of diodes, respectively. To achieve high step‐down voltage conversion ratios combined with high efficiency and high output current capabilities, several topologies and PWM techniques have been proposed [8, 14, 16–48].…”

Section: Introductionmentioning

confidence: 99%

“…A hybrid of the quadratic and series capacitor concept, proposed in [30], offers a wide duty cycle range and improved efficiency due to lower voltage stress on the devices but at the cost of a significantly high number of components. However, the most renown hybrid case is the switched/series capacitor concept [31][32][33][34][35][36][37]. Based on this, an expandable four-phase interleaved voltage step-down converter with quadruple conversion ratio (D/4) and low switch voltage stress was presented in [31].…”

Section: Introductionmentioning

confidence: 99%

“…Based on the [32] topology, the converter in [33] has a lower number of components and operates in two or three phase mode but the conversion ratio is only D /3. A four‐phase converter with quadruple conversion ratio and low capacitor count is reported in [34]. Contrary to the low number of capacitors is the high number of semiconductor switches needed for the converter implementation.…”

Section: Introductionmentioning

confidence: 99%

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A non‐isolated DC‐DC converter with low voltage stress and high step‐down voltage conversion ratio

Syrigos

Christidis

Mouselinos

et al. 2021

IET Power Electronics

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This work focuses on a new non-isolated interleaved DC-DC converter with very high step-down voltage conversion ratio. By employing the switched/series capacitor concept, along with the proper component interconnection, the converter features a high step-down voltage conversion ratio where, in the private case of equal duty ratios, it is six times higher than the conventional buck converter. This high step-down voltage conversion ratio is achieved with the lowest number of components compared to other similar topologies of the same conversion ratio. Also, due to the blocking/series capacitors, the voltage stress on the switches is reduced, improving the converter efficiency. One of the key features of the proposed converter is the inherent automatic current sharing between the interleaved phases, which in the case of equal duty ratios, is uniformly distributed. To add on, due to the use of only two interleaved phases, the converter has a wide output voltage range, since the duty cycle can be extended to 0.5. To validate the proposed converter operation, a 250 W wide-input/wide-output experimental prototype was built, achieving a peak efficiency of 94%. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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Multilevel Series-Capacitor Buck Converter

Roberts,

Prodić

2024

2024 IEEE Applied Power Electronics Conference and Exposition (APEC)

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A Multiphase Series-Capacitor Buck Converter with Reduced Flying Capacitor Volume and Auxiliary Start-Up Circuit

Cited by 6 publications

References 19 publications

Geometrical State-Plane Analysis of Resonant Switched-Capacitor Converters: Demonstration on the Cascaded Multiresonant Converter

Geometrical State-Plane Analysis of Resonant Switched-Capacitor Converters: Demonstration on the Cascaded Multiresonant Converter

A non‐isolated DC‐DC converter with low voltage stress and high step‐down voltage conversion ratio

Multilevel Series-Capacitor Buck Converter

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