ABSTRACT

Data centers, the backbone of today's information era, are expected to consume ~73 billion kWh in 2020, which amounts to ~$7.3 billion in electricity cost in the U.S. alone. This is one of the fastest growing loads on the electric grid in the U.S. as well as worldwide, because of customers' soaring demands for online data and cloud computing. This rapid-increasing consumption significantly contributes to global carbon emissions. Therefore, updating the power delivery for data centers with improved efficiency is an important societal need. The goal of this project is to address this power consumption bottleneck by using a new power distribution and conversion architecture that is compact, scalable, ultra-efficient, low-heat, low-cost, and reliable. If successful, a wide application of the proposed system could result in more than 8.1 billion kWh or ~$810 million annual savings in electricity consumption for data centers in the U.S. alone. These savings would, in turn, reduce harmful greenhouse gas emission of ~1.3 million passenger cars from U.S. roads. The impact can be further amplified by adoptions of the proposed system and its sub-systems in other information technology applications, such as communication systems, automotive, high-performance portable devices, etc. The research will be conducted by graduate students and undergraduate students who will be equipped with the knowledge and skills in integrated power electronics and energy efficiency for future opportunities in both professional and educational development. The research will also involve educational efforts including official curriculum offerings and outreach activities to K-12 students.

To achieve the research goal, the team will explore a radically different power distribution and management architecture for future green data centers and other information technology systems. Employing new converter topologies that can efficiently support large conversion ratios, the architecture reduces the number of power conversion stages from the grid to core voltages from four or more to only two. The first stage, converting grid AC voltage to a DC bus voltage, electrically stack server boards in close proximity in a server rack to allow each of them to handle only a fraction of the input grid AC voltage, leading to ultra-high power conversion efficiency, low cost and high reliability. This first conversion stage also exploits a novel, experimentally validated smart-cable method that can significantly reduce on-board heat, leading to substantial thermal management cost reductions. For the second stage converting the DC bus to core voltages, the research team will explore a new direct-conversion hybrid DC-DC converter topology family to enable superior efficiency and power density at extremely large conversion ratios. The research plan includes design, fabrication, and verification of multiple new hybrid converter topologies, integrating different types of AC-DC and DC-DC hybrid converters, smart-cable solution design and implementation, system failure protection circuit implementation and test, system scaling for different specifications and applications, and benchmarking against existing solutions.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

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