AC Smart Fuse Circuit for Rapid Server Power Fault Isolation

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Solution Overview

Problem

Conventional fuses and relays used in large-scale server networks are slow to react to faults, leading to power losses and potential concurrent failures of multiple servers connected to a single power distribution unit, which complicates maintenance and increases cooling needs due to energy wastage.

Innovation Solution

A circuit, referred to as an AC smart fuse, is introduced that includes a relay responsive to disabling signals, a sensor for measuring power levels, a detector for emitting fault signals when excessive power is detected, and a controller that manages these signals to quickly disconnect power to a load in case of a fault, allowing for configurable power thresholds and minimizing power losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional fuses are used to protect against short-circuits, then protection is provided, but the response time is slow and replacement is required after each fault

Engineering Contradiction:
Improveprotection capabilityVSAvoidresponse time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the mechanical fuse system with an electronic protection circuit that uses a microcontroller, current sensor, and solid-state switching device. This substitution enables digital measurement and control of current, allowing for instantaneous fault detection and response without the need for physical fuse replacement.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a solid-state switching device as an intermediary between the power source and load, controlled by a microcontroller that monitors current through a sensor. This intermediary system enables rapid disconnection upon fault detection, eliminating the slow response inherent in conventional fuse systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If relays are used to protect servers from short-circuits, then protection is provided and relays can be rearmed, but the response time is very slow and power losses occur through relay contacts

Engineering Contradiction:
Improveprotection capabilityVSAvoidpower loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent replaces the mechanical relay system with a solid-state switching device controlled by a microcontroller. This eliminates the need for mechanical contacts that cause power losses and slow response times, while maintaining the ability to protect and rearm the circuit electronically.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operational parameters of the switching device from mechanical (relay contacts) to electronic (solid-state), thereby reducing power loss and improving response time. The solid-state device operates with minimal voltage drop compared to mechanical relay contacts.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a single power distribution unit serves multiple servers, then power delivery is simplified, but the loss of one PDU causes concurrent loss of multiple servers

Engineering Contradiction:
Improvepower distribution structureVSAvoidsystem availability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent divides the power distribution system into independent protected channels, each with its own current monitoring and switching device. This segmentation allows individual server protection while maintaining overall system simplicity, so that a fault in one channel does not affect other channels or servers.

Inventive Principle:
Principle #1Segmentation

4Reliability

If fuses and relays are used in series to protect against electrical faults, then protection is provided, but the response time remains slow and power losses occur

Engineering Contradiction:
Improveprotection capabilityVSAvoidresponse time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the series combination of mechanical fuse and relay with a single integrated electronic protection circuit using a microcontroller, current sensor, and solid-state switching device. This integration eliminates the sequential operation delays inherent in series mechanical components, enabling instantaneous fault response.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 AC smart fuse provides faster fault response times, reduces power losses, and allows for controlled power delivery, thereby enhancing the reliability and efficiency of power distribution in large-scale server networks while minimizing the impact of individual unit failures.

Implementation Method 1

a relay (22) connecting the output connector (20) to a source of AC power, the relay (22) being responsive to a disabling signal to disconnect the output connector (20) from the source of AC power

Methodology Applied
Scientific EffectElectromagnetic actuation: Electromagnet

Implementation Method 2

A sensor (38) senses a level of power delivered to the load via the output connector (20)

Methodology Applied
Scientific EffectElectrical measurement: Ohmmeter

Data Source

PatentEP3952045A1Circuit implementing an ac smart fuse for a power distribution unit
Publication Date: 2022.02.09 OVH
  • EP3952045A1 patent drawingFigure 1
  • EP3952045A1 patent drawingFigure 2
  • EP3952045A1 patent drawingFigure 3

AI summary

A circuit comprises an output connector connectable to a load. A relay selectively connects the output connector to an AC power source. The relay is responsive to a disabling signal to disconnect the output connector from the AC power source. A latch maintains a fault signal until it receives a rearm signal. A logic combiner generates the disabling signal when it receives the fault signal. A sensor senses a difference between a current being delivered to the load and a current returning from the load. A detector emits the fault signal when when the difference between the current being delivered to the load and the current returning from the load exceeds a maximum differential current set-point. A controller receives a user command to rearm the circuit, and in response to receiving the user command, emits the rearm signal and ceases the emission of the fault signal.