Server Fan Speed Control for Temperature Fluctuation Stability

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Solution Overview

Problem

Controlling the angular speed of a fan in server systems with multi-core CPUs is challenging due to slight temperature fluctuations, leading to fan tremors, noise, and increased power consumption, as existing methods like PID feedback control struggle to maintain stability.

Innovation Solution

A method that adjusts the fan's angular speed based on an error value and a pulse width modulation value, using an adjustment constant to stabilize the fan speed and reduce unnecessary changes, thereby minimizing noise and power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the fan speed is adjusted in response to slight temperature changes, then the temperature control precision is improved, but the fan stability deteriorates causing tremors and noise

Engineering Contradiction:

Improvetemperature control precisionVSAvoidfan stability

Core Design Contradiction:

Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent implements a feedback control mechanism that monitors temperature changes and adjusts fan speed accordingly. When the temperature difference between consecutive readings exceeds a threshold, the fan speed is adjusted; otherwise, it remains constant. This feedback approach allows precise temperature control while maintaining fan stability by only responding to significant temperature changes.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes the control parameter from continuous fan speed adjustment to discrete adjustment based on temperature threshold. By introducing a threshold parameter (temperature difference threshold), the system transforms continuous temperature variations into discrete control actions, thereby stabilizing the fan while maintaining temperature control precision.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If the fan speed is frequently adjusted to maintain temperature, then the temperature stability is improved, but the power consumption increases

Engineering Contradiction:

Improvetemperature stabilityVSAvoidpower consumption

Core Design Contradiction:

Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The patent employs periodic temperature monitoring and conditional fan speed adjustment. Instead of continuous adjustment, the system periodically checks temperature differences and only adjusts fan speed when necessary (when temperature change exceeds threshold). This periodic action maintains temperature stability while reducing unnecessary power consumption from frequent fan adjustments.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent applies partial action by adjusting the fan speed only when temperature changes exceed a certain threshold, rather than continuously adjusting for every temperature fluctuation. This partial adjustment approach maintains adequate temperature stability while significantly reducing power consumption compared to continuous adjustment.

Inventive Principle:

Principle #16Partial or excessive action

3Speed

If the fan speed is adjusted based on PID feedback control, then the temperature response speed is improved, but the system complexity increases leading to control instability

Engineering Contradiction:

Improvetemperature response speedVSAvoidcontrol system complexity

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The patent extracts the essential control function from complex PID feedback control, retaining only the necessary temperature monitoring and conditional adjustment logic. By removing unnecessary complexity while keeping the core temperature-response functionality, the system achieves adequate temperature response speed with simplified control logic.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using complex PID control to achieve temperature stability, the patent inverts the approach by using simple threshold-based control. The system inverts the conventional wisdom that complex control is needed for stability, demonstrating that simple conditional logic can achieve both temperature response and stability with reduced complexity.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS11333156B2Method for controlling angular speed of a fan by adjusting an integral value based on minimum or maximum output

Publication Date: 2022.05.17 INVENTEC PUDONG TECH CORPOARTION

AI summary

A method for controlling an angular speed of a fan of a computer system includes obtaining an error value; obtaining an adjusted error value by adjusting the error value using an adjustment constant when an absolute value of the error value is not larger than a predetermined value; obtaining a total output value according to at least the adjusted error value; and controlling the angular speed of the fan according to the total output value. The total output value is positively related to a pulse width modulation value, and the angular speed of the fan increases when the pulse width modulation value increases.