Fan Motor Control Device Abnormality Detection via Periodic Power Cycling
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Solution Overview
Problem
Existing fan motor control devices can only determine motor abnormalities at the time of activation, limiting the frequency and accuracy of abnormality judgments.
Innovation Solution
A fan motor control device that includes a rotational speed detecting unit and an abnormality decision control unit, which repeatedly switches the power supply to the fan motor between on and off during operation to increase the frequency of abnormality judgments based on rotational speed thresholds and times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If abnormality judgment is performed only at activation time, then the control system remains simple, but the abnormality detection frequency and accuracy are limited
Solution Approach 1:
The patent implements periodic abnormality judgment by repeatedly switching the fan motor between on and off states during operation. The control unit performs multiple abnormality judgments at different time points (activation, during operation, and shutdown), transforming a single-point check into a periodic multi-point assessment system. This increases detection frequency and accuracy without requiring fundamentally new hardware.
Solution Approach 2:
The system uses rotational speed detection feedback to determine abnormality. The detection unit continuously monitors rotational speed, and the control unit compares actual speed against expected values at different operational stages. This feedback mechanism enables accurate abnormality detection while maintaining relatively simple control logic based on predefined judgment criteria.
2Reliability
If the fan motor operates continuously for cooling, then cooling effectiveness is maintained, but abnormality detection opportunities are limited
Solution Approach 1:
The patent introduces periodic on-off cycling of the fan motor during operation to create multiple abnormality judgment opportunities. By switching the motor between on and off states multiple times, the system performs abnormality checks at each transition point, transforming a single detection opportunity into multiple opportunities without compromising overall cooling function.
Solution Approach 2:
The system performs preliminary abnormality judgments at activation and shutdown phases before full operational stress occurs. These preliminary checks identify potential issues early, allowing for preventive measures before the abnormality affects cooling performance during continuous operation.
3Measurement precision
If rotational speed detection is performed continuously, then abnormality detection accuracy improves, but energy consumption increases
Solution Approach 1:
The patent implements periodic rotational speed detection synchronized with the fan motor's on-off cycling. Rather than continuous monitoring, the system detects rotational speed at specific intervals corresponding to abnormality judgment points. This periodic approach maintains adequate detection accuracy while significantly reducing energy consumption compared to continuous monitoring.
Solution Approach 2:
The system performs rotational speed detection at sufficient frequency to capture abnormality conditions without excessive redundancy. By targeting detection at critical moments (activation, operational transitions, shutdown), the system achieves necessary measurement precision without the energy waste of constant high-frequency monitoring.
Data Source
AI summary
A fan motor control device configured to control driving of a fan motor for cooling a CPU includes: a rotational speed sensor configured to detect a rotational speed of the fan motor; and an abnormality decision control unit configured to execute an abnormality decision mode of repeatedly switching between on and off of power supply to the fan motor during an operation of the CPU, and determine abnormality of the fan motor based on the rotational speed of the fan motor during the execution of the abnormality decision mode.