A Series-Stacked Power Delivery Architecture With Isolated Differential Power Conversion for Data Centers

In this paper, an alternative method to achieve more efficient dc power distribution and voltage regulation for future data centers is presented. This paper describes a series-stacked power delivery architecture, where servers are connected electrically in series, thereby, providing inherent step down of voltage. Server voltage regulation is performed by differential power converters, which only process the mismatch power between servers. The bulk power flows with no power processing, yielding greatly increased system efficiency compared to conventional architectures. We demonstrate the series-connected architecture with an experimental proof of concept and compare the proposed architecture with a conventional dc power delivery architecture employing a best-in-class power supply unit for servers. The proposed power delivery architecture is validated with a series-stacked server rack consisting of four 12 V servers, powered from a 48 V dc bus, performing two different real-world operations: web traffic management and computation. Through experimental measurements, we demonstrate up to a 40x reduction in power conversion losses compared to state-of-the-art hardware, and an overall best-case system conversion efficiency of 99.89%.

[1]  Dzmitry Kliazovich,et al.  DENS: Data Center Energy-Efficient Network-Aware Scheduling , 2010, GreenCom/CPSCom.

[2]  R. Pilawa-Podgurski,et al.  Re-thinking data center power delivery: Regulating series-connected voltage domains in software , 2013, 2013 IEEE Power and Energy Conference at Illinois (PECI).

[3]  Dragan Maksimovic,et al.  Nonlinear control design for the photovoltaic isolated-port architecture with submodule integrated converters , 2013, 2013 IEEE Energy Conversion Congress and Exposition.

[4]  Henry Shu-Hung Chung,et al.  Dynamic hysteresis band control of the buck converter with fast transient response , 2005, IEEE Transactions on Circuits and Systems II: Express Briefs.

[5]  P. T. Krein,et al.  Differential Power Processing for Increased Energy Production and Reliability of Photovoltaic Systems , 2013, IEEE Transactions on Power Electronics.

[6]  D. Maksimovic,et al.  Architectures and Control of Submodule Integrated DC–DC Converters for Photovoltaic Applications , 2013, IEEE Transactions on Power Electronics.

[7]  D.M. Divan,et al.  Performance characterization of a high power dual active bridge DC/DC converter , 1990, Conference Record of the 1990 IEEE Industry Applications Society Annual Meeting.

[8]  R. C. N. Pilawa-Podgurski,et al.  Sub-module differential power processing for photovoltaic applications , 2013, 2013 Twenty-Eighth Annual IEEE Applied Power Electronics Conference and Exposition (APEC).

[9]  Torsten Lehmann,et al.  Dual-Stacked Current Recycling Linear Regulators With 48% Power Saving for Biomedical Implants , 2013, IEEE Transactions on Circuits and Systems I: Regular Papers.

[10]  C. Schaef,et al.  A multi-level ladder converter supporting vertically-stacked digital voltage domains , 2013, 2013 Twenty-Eighth Annual IEEE Applied Power Electronics Conference and Exposition (APEC).

[11]  Philip T. Krein.  A discussion of data center power challenges across the system , 2010, 2010 International Conference on Energy Aware Computing.

[12]  Philip T. Krein,et al.  Power delivery for series connected voltage domains in digital circuits , 2011, 2011 International Conference on Energy Aware Computing.

[13]  Y. C. Cheng,et al.  A 580 kHz switching regulator using on-off control , 1987 .

[14]  J. Koomey.  Worldwide electricity used in data centers , 2008 .

[15]  Philip T. Krein,et al.  Differential Power Processing for DC Systems , 2013, IEEE Transactions on Power Electronics.

[16]  Johann W. Kolar,et al.  Accurate Power Loss Model Derivation of a High-Current Dual Active Bridge Converter for an Automotive Application , 2010, IEEE Transactions on Industrial Electronics.

[17]  Bruce Nordman,et al.  ERNEST ORLANDO LAWRENCE BERKELEY NATIONAL LABORATORY , 2011 .

[18]  D.J. Perreault,et al.  Very-High-Frequency Resonant Boost Converters , 2007, IEEE Transactions on Power Electronics.

[19]  Robert C. N. Pilawa-Podgurski,et al.  A series-stacked architecture for high-efficiency data center power delivery , 2014, 2014 IEEE Energy Conversion Congress and Exposition (ECCE).

[20]  Dzmitry Kliazovich,et al.  e-STAB: Energy-Efficient Scheduling for Cloud Computing Applications with Traffic Load Balancing , 2013, 2013 IEEE International Conference on Green Computing and Communications and IEEE Internet of Things and IEEE Cyber, Physical and Social Computing.

[21]  Torsten Lehmann,et al.  Current recycling in linear regulators for biomedical implants , 2010, 2010 53rd IEEE International Midwest Symposium on Circuits and Systems.

[22]  Zheng Xu,et al.  Energy-efficient low-voltage operation of digital CMOS circuits through charge-recycling , 2004, 2004 Symposium on VLSI Circuits. Digest of Technical Papers (IEEE Cat. No.04CH37525).

[23]  Ali Heydari,et al.  High-efficiency server design , 2011, 2011 International Conference for High Performance Computing, Networking, Storage and Analysis (SC).

[24]  Enver Candan.  A series-stacked power delivery architecture with isolated converters for energy efficient data centers , 2014 .

[25]  S. Rajapandian,et al.  High-voltage power delivery through charge recycling , 2006, IEEE Journal of Solid-State Circuits.