Fan Control System Modulating Speed to Prevent Resonance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional fan control systems using pulse width modulation (PWM) fans often cause resonance due to overlap between fan vibration frequencies and natural frequencies of computer casings or hard disks, leading to noise, reduced hard disk performance, and increased manufacturing costs.
Innovation Solution
A fan control system with a detecting unit generating a PWM signal based on temperature data, which includes a rotational speed modulating unit that adjusts the fan's speed outside specific resonance ranges to prevent resonance, using a BIOS to store and generate the necessary PWM signals and duty cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the fan rotational speed is linearly modulated according to temperature detecting signals, then the heat dissipation efficiency is improved, but resonance occurs due to overlap between fan vibration frequency and natural frequency of computer casing or hard disk
Solution Approach 1:
The patent applies dynamics by making the fan speed control non-linear and adaptive. Instead of a fixed linear relationship between temperature and rotational speed, the system dynamically adjusts the rotational speed based on detected resonance conditions. The control mechanism modifies the speed curve to avoid specific frequency ranges that cause resonance, while maintaining effective heat dissipation at other speeds.
Solution Approach 2:
The patent changes the parameter relationship between temperature and rotational speed from a fixed linear function to a variable function that accounts for resonance avoidance. By introducing resonance frequency detection and adjustment, the system modifies the rotational speed parameter based on both temperature requirements and vibration characteristics, creating a multi-parameter control system that prevents resonance while maintaining heat dissipation efficiency.
2Productivity
If the fan rotational speed is increased to improve heat dissipation, then the cooling performance is improved, but resonance and noise increase
Solution Approach 1:
The system dynamically adjusts fan rotational speed based on real-time detection of resonance conditions. When resonance is detected at higher speeds, the control mechanism automatically modifies the speed profile to avoid resonant frequencies, thereby maintaining cooling performance while reducing noise and vibration. This dynamic adaptation allows the fan to operate efficiently without consistently generating harmful noise levels.
3Reliability
If the fan rotational speed is modulated to prevent resonance, then the operational stability is improved, but the control system complexity increases
Solution Approach 1:
The patent implements feedback by detecting resonance conditions during fan operation and using this information to adjust the rotational speed in real-time. The system monitors vibration characteristics and feeds this information back to the control mechanism, which then modifies the speed profile to avoid resonant frequencies. This closed-loop feedback approach maintains operational stability without requiring complete redesign of the control system architecture.
Solution Approach 2:
The system performs preliminary action by pre-establishing resonance avoidance criteria and control algorithms before actual fan operation. The control mechanism is pre-programmed with knowledge of resonant frequency ranges and the methods to avoid them, allowing the system to prevent resonance issues before they occur rather than reacting to them after they manifest. This reduces the complexity of real-time decision-making during operation.
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 prevents resonance by modulating the fan's rotational speed outside critical ranges, enhancing operational stability and reducing noise and manufacturing costs.
Implementation Method 1
a fan driving unit for driving the fan
Implementation Method 2
By modulating the duty cycle of the PWM signal, an analog signal is encoded, and the current is added on an analog loading with repeating pulse sequence of on and off
Implementation Method 3
A temperature detecting unit is for detecting temperature of a CPU or a key component so as to generate a temperature detecting signal
Data Source
AI summary
A fan control system includes a host device including a detecting unit for detecting a component so as to generate a detecting signal. The host device further includes BIOS for storing relationship information between the detecting signal and a rotational speed of a fan and for generating a rotational signal according to the detecting signal and the relationship information. The fan control system further includes a fan device including a fan and a fan driving unit for driving the fan. The fan device further includes a rotational speed modulating unit for controlling the fan driving unit to drive the fan to rotate at a second rotational speed outside a first range when a first rotational speed corresponding to the rotational signal according to the relationship information is within the first range.