Power Shelf Redundancy for Server Rack AC Outages
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Solution Overview
Problem
Data centers face significant challenges in maintaining high power availability and reducing environmental impact due to high energy consumption and reliance on costly backup systems, with existing solutions often failing to provide seamless power continuity during AC outages and inefficiently managing battery backup units.
Innovation Solution
A power shelf system within server racks that utilizes a (2+1) redundant configuration of power supply units (PSUs) and backup battery units (BBUs), allowing seamless switching between AC and DC power sources, with each PSU receiving one phase of three-phase AC input and sharing output currents to maintain balanced input AC phases, and incorporating a DC-DC converter for efficient power distribution and periodic BBU testing without service interruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If centralized UPS systems are used to ensure power continuity, then power availability is improved, but system complexity and cost increase
Solution Approach 1:
The patent divides the centralized UPS system into distributed power shelf units, each serving a specific rack. Each power shelf contains integrated PSUs and BBUs that work independently, eliminating the need for a single complex centralized UPS system while maintaining power availability through localized backup capabilities.
Solution Approach 2:
The patent embeds backup battery units (BBUs) directly within the power supply units (PSUs) of each power shelf, creating a nested structure where the BBU is contained within the PSU assembly. This integration reduces system complexity by combining multiple functions into a single modular unit while ensuring continuous power supply.
2Reliability
If frequent BBU testing is performed to ensure backup reliability, then power reliability is improved, but service interruptions increase
Solution Approach 1:
The patent implements dynamic load sharing among multiple PSUs in each power shelf, allowing the system to adaptively adjust which PSUs are actively testing their BBUs and which are providing power to the load. This dynamic allocation ensures that backup testing occurs without causing service interruptions, as other PSUs can compensate for the testing PSU.
Solution Approach 2:
The patent changes the operational parameters of PSUs during BBU testing by adjusting load distribution and power allocation in real-time. When one PSU tests its BBU, other PSUs increase their power output to maintain stable system operation, thereby allowing frequent testing without service interruptions.
3Device complexity
If multiple PSUs draw power from the same AC circuit, then device complexity is reduced, but power availability decreases due to circuit breaker tripping
Solution Approach 1:
The patent employs asymmetric load distribution strategies where PSUs are deliberately assigned to different AC circuits in a non-uniform pattern. This asymmetric allocation prevents simultaneous high-draw operations on the same circuit, avoiding breaker tripping while maintaining simple power distribution architecture. The system monitors and balances loads across circuits to ensure availability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system ensures continuous power supply during AC outages, reduces the need for centralized UPS systems, and minimizes environmental impact by optimizing power usage and reducing the frequency of BBU testing overlaps, thereby enhancing reliability and efficiency while decreasing resource depletion and greenhouse gas emissions.
Implementation Method 1
A power shelf for serving a power zone within a server rack includes a power supply circuit that converts AC power to DC power
Implementation Method 2
A power supply circuit includes: an AC-to-DC circuit configured to convert an alternating current (AC) phase from multi-phase AC inputs to a direct current (DC)
Implementation Method 3
a bulk capacitor electrically coupled between the shared voltage node and an electric ground to hold power for at least one cycle of the AC phase
Implementation Method 4
a step-up converter electrically coupled, in series, between the DC interface and the asymmetric conductance component
Data Source
AI summary
At least one embodiment of this disclosure includes a power shelf for serving a power zone within an IT equipment rack. The power shelf includes: a DC bus configured to provide DC power to rack-mounted equipment within the power zone; multiple pairs of backup battery units (BBUs) and power supply units (PSUs), wherein the multiple pairs include at least a redundant pair, such that voltage and power is supplied through the DC bus sufficient to power the rack-mounted equipment even when one of the multiple pairs is inoperative; and a power circuit, in each PSU of each of the multiple pairs, configured to rectify an AC phase from an external multi-phase AC power source, wherein the power circuit is configured to draw power from one of the BBUs paired to the PSU when the PSU fails to provide power sufficient to power the rack-mounted equipment.