Fan Control System Back-EMF Phase Adjustment for Vibration Reduction
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Solution Overview
Problem
Conventional fan control systems experience significant vibrations due to hard-switching methods, which are not effectively reduced by existing soft-switching techniques or mechanism designs, leading to increased costs and inefficiencies.
Innovation Solution
A control method and system that detects rotational speed and rotor position to generate a control signal, adjusts the phase of the Back-EMF waveform, and outputs a switch control signal, utilizing a detection module, control module, and Back-EMF module to reduce vibrations while maintaining the current driving circuit and architecture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If hard-switching method is used to drive the fan, then the control system is simple, but the vibration level increases significantly (larger than 1.5G)
Solution Approach 1:
The patent changes the timing parameter of the switch control signal by adjusting the turn-off timing of the switching element. Specifically, it controls the switching element to turn off before the back-EMF waveform reaches its peak value, thereby changing the operating parameters to reduce vibration while maintaining control system simplicity
Solution Approach 2:
The patent employs feedback by detecting the back-EMF waveform of the motor and using this information to control the timing of the switching element. The control system monitors the back-EMF signal and adjusts the switch turn-off timing based on the detected waveform characteristics, creating a closed-loop control mechanism that reduces vibration
2Object-generated harmful factors
If soft-switching method is used to reduce vibrations, then the vibration is partially reduced, but the vibration level remains larger than 1.5G and is not effectively decreased
Solution Approach 1:
The patent applies preliminary action by controlling the switching element to turn off in advance before the back-EMF waveform reaches its peak. This proactive timing adjustment prevents the conditions that generate high vibration from occurring in the first place, rather than attempting to mitigate vibration after it is generated
Solution Approach 2:
The patent introduces dynamic control by continuously monitoring the back-EMF waveform and adjusting the switch turn-off timing in real-time based on the detected waveform characteristics. This dynamic adjustment allows the system to adapt to changing operating conditions and maintain optimal vibration reduction performance
3Object-generated harmful factors
If mechanism design such as anti-vibration pads is used, then the cost increases, but the vibration problem cannot be effectively solved and the frequency multiplication effect caused by the motor remains
Solution Approach 1:
The patent replaces the mechanical vibration reduction approach (anti-vibration pads) with an electrical control solution. By using electronic control of the switching timing based on back-EMF detection, the system achieves vibration reduction without adding mechanical components, thereby avoiding increased cost and structural complexity
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 solution significantly decreases fan vibrations, enhances efficiency, reduces electric pressure, and extends the product lifecycle by minimizing RMS current and average current, thereby reducing material and production costs.
Implementation Method 1
obtaining a Back-EMF waveform according to the control signal, the rotational speed, the rotor position and a waveform
Data Source
AI summary
A control method of a fan comprises steps of: detecting a rotational speed of a blade and a rotor position of the blade; generating a control signal according to the rotational speed and a predetermined rotational speed; obtaining a Back-EMF waveform according to the control signal, the rotational speed, the rotor position and a waveform; adjusting the phase of the Back-EMF waveform; and outputting a switch control signal.