PID Controller Reset Windup Prevention in Data Center Cooling

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Solution Overview

Problem

Existing temperature management systems for data centers face issues with control performance deterioration due to reset windup when transitioning from idle to operational states, leading to inefficient cooling and increased power consumption.

Innovation Solution

A temperature management system that includes temperature detection units, a cooling device, and a control unit with an idle state determination unit, accumulation value correction, and PID or PI control, which corrects the accumulation value of the integrator in the idle state to prevent reset windup and ensure stable cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If proportional control alone is used for cooling control, then the control response is fast, but control precision deteriorates due to reset windup when the cooling device operates at maximum capacity

Engineering Contradiction:
Improvecontrol response speedVSAvoidtemperature control precision
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent merges proportional control and integral control into a single control mechanism. The proportional control provides fast response by reacting to current temperature deviations, while the integral control accumulates past temperature errors to eliminate steady-state offset. This combination resolves the contradiction by maintaining both rapid response and precise temperature control, preventing reset windup through proper integration of the two control approaches.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements feedback control by continuously monitoring the temperature of electronic devices and adjusting the cooling device operation based on the difference between actual and target temperatures. The integral component accumulates feedback information over time, allowing the system to correct persistent temperature deviations and maintain precise control even when the cooling device operates at maximum capacity for extended periods.

Inventive Principle:
Principle #23Feedback

2Speed

If the cooling device operates at maximum capacity continuously, then the temperature is reduced quickly, but energy consumption increases and the device cannot respond to subsequent temperature rises

Engineering Contradiction:
Improvetemperature reduction speedVSAvoidcooling device energy consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamic control by continuously adjusting the cooling device operation based on real-time temperature conditions. Rather than operating at maximum capacity continuously, the system dynamically modulates the cooling output to match the actual cooling demand. This allows rapid temperature reduction when needed while consuming less energy during periods when less cooling is required, and prepares the system to respond quickly to subsequent temperature rises.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The integral control component ensures continuous adjustment of the cooling device operation to maintain optimal cooling performance. By continuously accumulating temperature error information and adjusting the control output accordingly, the system maintains effective cooling action without unnecessary maximum-capacity operation, thereby reducing energy consumption while preserving the ability to respond to temperature changes.

Inventive Principle:
Principle #20Continuity of useful action

3Measurement precision

If multiple cooling devices are controlled independently, then each device can be optimized individually, but the overall temperature distribution control becomes complex and less efficient

Engineering Contradiction:
Improveindividual device temperature controlVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies a universal control algorithm that can manage multiple cooling devices with a single integrated control system. Rather than implementing separate control loops for each cooling device, the system uses a unified proportional-integral controller that processes temperature data from multiple sensors and coordinates multiple cooling devices. This reduces control system complexity while maintaining the ability to optimize individual device operation through the shared control logic.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 effectively suppresses control performance deterioration and ensures stable, efficient cooling of electronic devices by preventing excessive accumulation of deviations in the integrator, thereby reducing power consumption and maintaining target temperatures effectively.

Implementation Method 1

temperature detection units (32) which individually detect temperatures of a plurality of electronic devices

Methodology Applied
Scientific EffectThermal energy detection: Thermal Radiation

Implementation Method 2

a cooling device (12) which cools the electronic devices

Methodology Applied
Scientific EffectHeat transfer: Convection

Data Source

PatentEP2894524B1Temperature administration system
Publication Date: 2020.01.15 FUJITSU LTD
  • EP2894524B1 patent drawingFigure 1~2
  • EP2894524B1 patent drawingFigure 3
  • EP2894524B1 patent drawingFigure 4

AI summary

[Problem] There is provided a temperature management system capable of suppressing deterioration in control performance attributed to reset windup, and efficiently cooling an electronic device such as a computer. [Solution] A temperature management system includes: temperature detection units (32) which individually detect temperatures of a plurality of electronic devices each changing an amount of heat generation depending on its operational state; a cooling device (12) which cools the electronic devices; and a control unit (30) which controls the cooling device (12) depending on outputs from the temperature detection units (32). The control unit (30) includes: an idle state determination unit (44) which determines whether or not the electronic devices are in an idle state; a manipulated variable calculation unit (40) which has an integrator (50) and calculates a manipulated variable by using a difference between a target value and a controlled variable; and an accumulation value correction unit (45) which corrects an accumulation value of the integrator (50) with a predetermined value when the idle state determination unit (44) determines that the electronic devices are in the idle state.