Systems and methods for fan typing and anomaly detection
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Solution Overview
Problem
Current information handling systems face challenges in accurately distinguishing between different types of fans and detecting anomalies such as fan failures or performance degradation, particularly due to the limitations of dedicated fan typing circuitry and wiring which can only grossly determine fan types and fail to detect specific issues like wobble or debris affecting fan performance.
Innovation Solution
The system employs a software-based approach using pulse width modulation (PWM) control signals and tachometer signals to determine fan types by comparing frequency outputs against expected curves, and detects anomalies by analyzing tachometer signal histograms for inconsistencies, allowing for precise fan typing and anomaly detection without dedicated circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dedicated circuitry and wiring are used for fan typing, then fan type determination can be performed, but the system can only grossly determine fan types (standard vs. high performance) without additional specificity
Solution Approach 1:
The patent replaces the mechanical/electrical dedicated circuitry and wiring system with a software-based measurement system. The system uses a processor to generate PWM control signals and measure tachometer signal frequencies to determine fan types, eliminating the need for specialized hardware circuitry while achieving precise fan type identification through software analysis of electrical signals.
Solution Approach 2:
The patent introduces PWM control signals and tachometer signals as intermediary elements to enable fan type determination. Instead of direct hardware comparison, the system uses these signal intermediaries to indirectly measure fan characteristics and identify fan types with high precision through frequency analysis.
2Reliability
If dedicated circuitry is used for fan typing, then fan type can be determined, but the system fails to detect specific issues like wobble or debris affecting fan performance
Solution Approach 1:
The patent implements feedback by continuously monitoring tachometer signal frequencies at different PWM duty cycles and comparing them against expected frequency curves. This feedback mechanism allows the system to detect deviations indicating fan anomalies such as wobble or debris, providing reliable anomaly detection through iterative measurement and comparison.
Solution Approach 2:
The patent applies partial action by testing fan performance at specific PWM duty cycles (including a threshold duty cycle) rather than continuous operation. This selective measurement approach enables detection of performance issues without requiring full system operation, achieving reliable anomaly detection through targeted measurements.
3Measurement precision
If software-based PWM and tachometer analysis is used, then accurate fan typing and anomaly detection are achieved, but system complexity increases
Solution Approach 1:
The patent applies universality by using the existing PWM control and tachometer signal infrastructure for multiple purposes: fan type determination, anomaly detection, and performance monitoring. This multi-functional approach achieves high measurement precision without adding dedicated hardware complexity, as the same signals serve multiple diagnostic functions.
Solution Approach 2:
The patent implements self-service by utilizing the fan's own tachometer signal output for self-diagnosis and type identification. The fan essentially provides its own measurement data through the tachometer signal, eliminating the need for external sensing hardware and reducing overall system complexity while maintaining high measurement accuracy.
4Difficulty of detecting and measuring
If existing fan typing methods are used, then basic fan type determination is possible, but subtle issues like fan wobble and performance degradation cannot be detected
Solution Approach 1:
The patent applies preliminary action by establishing expected tachometer frequency curves for different fan types before actual measurement. These pre-established reference curves enable the system to detect subtle deviations indicating wobble or performance degradation, allowing early detection of anomalies before they lead to failure.
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
This method enables accurate fan typing and anomaly detection, reducing system costs and increasing accuracy, while also detecting subtle issues like fan wobble and performance degradation, thereby improving fan management and thermal control in information handling systems.
Implementation Method 1
supply a pulse width modulation (PWM) control signal with a first PWM duty cycle to an input of a given fan
Implementation Method 2
receive a tachometer signal output by the given fan while the PWM control signal has the first PWM duty cycle, the tachometer signal including a pair of pulses for each rotation of the given fan such that the frequency of the tachometer signal expressed in terms of revolutions per minute (RPM) is proportional to the speed of the given fan
Data Source
AI summary
Systems and methods for fan typing and anomaly detection may provide a pulse width modulation (PWM) control signal with a predetermined threshold duty cycle to a fan, receive a tachometer signal from the fan while the PWM control signal has the threshold duty cycle, and compare the frequency of the tachometer signal (expressed in revolutions per minute) to an expected tachometer frequency for fans of a first fan type with the PWM control signal having the threshold duty cycle, according to an RPM vs. PWM curve specified for fans of the first fan type. The systems and methods may determine, based on the comparison, that the fan is of the first fan type and provide an indication that the fan is of the first fan type to a fan controller. Deviations from expected tachometer responses may indicate an anomaly, such as an actual fan failure or a predicted fan failure.