Failover Switch Controller for Uninterruptible Power Supply

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Solution Overview

Problem

Modern data centers face challenges in providing uninterrupted power to protected load devices, as existing power supply failover systems lack efficient monitoring and switching mechanisms to seamlessly transition between AC and DC power sources, leading to potential power outages and system failures.

Innovation Solution

The implementation of a power supply failover system that utilizes a failover switch controller to monitor AC and DC power sources, enabling digitally controlled switching between AC and DC power supplies, incorporating bypass phase switches, AC phase switches, DC switches, and battery isolation switches to ensure uninterrupted power through failover and failback transitions, while managing overcurrent protection to prevent system failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a power supply failover system is implemented to ensure uninterrupted power to protected load devices, then reliability is improved, but device complexity increases due to multiple switching mechanisms and monitoring systems

Engineering Contradiction:
Improveuninterrupted power supplyVSAvoidswitching mechanisms
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The power supply system is segmented into multiple independent power sources (AC power source and DC battery power source) with separate monitoring and switching circuits for each. This segmentation allows the system to maintain reliability through redundancy while managing complexity by organizing functions into distinct modules that can be independently controlled and monitored.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary actions by pre-charging battery banks before failure occurs and pre-configuring switching circuits in both AC and DC paths. The monitoring circuits continuously assess power quality in advance, allowing the system to transition between power sources seamlessly without waiting for complete failure, thus maintaining reliability while reducing the complexity of emergency response mechanisms.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If multiple switching mechanisms (bypass phase switches, AC phase switches, DC switches) are implemented to provide redundant switching paths, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improveredundant switching pathsVSAvoidswitching mechanisms
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The switching functionality is segmented into distinct circuits for AC power (with bypass and phase switches) and DC power (with battery isolation and DC switches). Each switching mechanism is dedicated to a specific power source and protection function, which maintains reliability through redundancy while managing complexity by avoiding the need for a single complex universal switch that would need to handle all scenarios.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The failover switch controller acts as an intermediary that coordinates all switching mechanisms. It monitors both AC and DC power sources and intelligently controls the bypass phase switch, AC phase switch, DC switch, and battery isolation switch based on real-time conditions. This intermediary approach maintains reliability through coordinated redundancy while reducing the effective complexity by centralizing control logic rather than requiring independent complex control for each switch.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If overcurrent protection is implemented during failover transitions, then reliability is improved, but device complexity increases due to additional monitoring and control circuits

Engineering Contradiction:
Improveovercurrent protectionVSAvoidmonitoring and control circuits
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The overcurrent protection function is merged with the existing failover control logic in the failover switch controller. The controller simultaneously monitors for power failures and overcurrent conditions, and coordinates switching actions with overcurrent protection in a unified control process. This merging maintains reliability by ensuring both protection functions are active while avoiding the complexity of separate independent overcurrent protection systems that would duplicate monitoring and control infrastructure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system performs preliminary overcurrent assessment before executing failover transitions. The failover switch controller monitors current levels in advance and only initiates switching when overcurrent conditions are resolved, preventing damage during transitions. This preliminary check maintains reliability by preventing protective device damage while managing complexity by integrating the check into the existing transition logic rather than adding separate protective infrastructure.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS9965365B2Power supply failover system and method
Publication Date: 2018.05.08 LITE ON INC

AI summary

A power supply failover system/method providing uninterruptable power to protected load devices (PLD) is disclosed. The system includes a failover switch controller (FSC) with inputs from an AC I/V monitor (AIV), AC cycle counter (ACC), failover switch timer (FST), and overcurrent protection timer (OPT). The FSC utilizes these inputs to control failsafe switching of a bypass phase switch (BPS) and AC phase switch (ACS) to the PLD when power from the APS is determined to be good by the AIV. When power from the APS is determined to be compromised by the AIV, the FPS disables the ACS/BPS and enables a DC switch (DCS) and battery isolation switch (BIS) to connect a DC source to the PLD after a time period determined by the FST. APS/DCS overcurrent protection is limited by OPT intervals allowing a smooth transition between the APS to DCS during power failover/failback.