Fan Motor Speed Correction via Lookup Table and Sample-Hold Circuit
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Solution Overview
Problem
Existing fan motor control systems, particularly those using PID controllers, face challenges in quickly adjusting rotational speeds when changing environments, leading to inrush waveforms and inefficiencies in cooling heat-generating components.
Innovation Solution
A system comprising a lookup table module, driver circuit, sample and hold circuit, and arithmetic circuit that stores and updates reference working periods for different rotational speeds across environments, allowing for automatic correction of motor speed by analyzing linearly changing data and generating corrected driving signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a PID controller system is used to control the motor of the fan to rotate at a constant rotational speed, then the rotational speed stability is improved, but the response time increases and inrush waveform is generated when the rotational speed command changes
Solution Approach 1:
The system pre-calculates and stores correction values for different rotational speed commands in a lookup table before actual operation. When the rotational speed command changes, the controller directly retrieves the pre-computed correction value from the lookup table, eliminating the need for real-time PID calculation and avoiding inrush waveforms while maintaining fast response.
Solution Approach 2:
The patent replaces the traditional PID control mechanism with a lookup table-based correction system. Instead of using continuous mathematical calculations and feedback loops, the system uses a discrete lookup table that maps rotational speed commands to correction values, substituting the mechanical PID control process with a simpler data retrieval and application process.
2Adaptability or versatility
If the fan is moved to a different environment, then the adaptability to new conditions is improved, but the rotational speed control accuracy deteriorates due to environmental changes
Solution Approach 1:
The system incorporates an environmental detection mechanism that monitors changes in operating conditions. When environmental changes are detected, the system automatically updates the lookup table with new correction values specific to the new environment, ensuring that rotational speed control accuracy is maintained across different operating conditions through adaptive feedback.
Solution Approach 2:
The lookup table is designed to be dynamic and updatable rather than static. The system can adapt its correction values based on environmental changes, allowing the control parameters to evolve dynamically with operating conditions while maintaining precise rotational speed control.
Data Source
AI summary
A system and a method for automatically correcting a rotational speed of a motor of a fan are provided. After the fan is moved from an open space to a closed space, a sample and hold circuit samples and holds working periods of a driving signal by which the motor is driven to rotate at a first rotational speed as a first sampled working period, and a working period of a driving signal by which the motor is driven to rotate at a second rotational speed. An arithmetic circuit calculates a difference between the first sampled working period and a first reference working period, and a difference between the second sampled working period and a second reference working period. The arithmetic circuit calculates other working periods of driving signals by which the motor is driven to rotate at other rotational speeds based on the differences.