Fan Impeller Electronic Control System for Tunnel Ventilation
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Solution Overview
Problem
Current tunnel fan systems face efficiency reductions due to long cable distances between control systems and motors, leading to energy loss from reflected waves and harmonics, which is critical in emergency situations like fires where high air evacuation is needed.
Innovation Solution
The electronic control system for fan impellers is integrated into the fan's supporting structure, using a variable frequency drive with a bypass module and harmonic compensation, allowing direct network connection at high temperatures, and featuring a thermally insulated metal box to reduce harmonic interference and enhance power factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the electronic control system is located in the electrical room at a distance from the fan, then the control system can be centrally managed, but the cable length increases causing reflected waves and harmonics that reduce energy delivery to the motor
Solution Approach 1:
The patent divides the control system into distributed electronic modules that can be placed near each fan unit, segmenting the previously centralized control architecture. This allows local control while maintaining centralized monitoring capabilities, reducing cable length to less than 1 meter and eliminating reflected waves and harmonics while preserving management flexibility
Solution Approach 2:
The patent transitions from a single centralized control location to a multi-dimensional distributed architecture where electronic modules can be positioned at multiple locations near different fan units. This spatial redistribution eliminates the trade-off between centralized management and energy efficiency by enabling both through hierarchical control structure
2Loss of energy
If the cable length is reduced to minimize energy loss, then energy delivery to the motor is maximized, but the control system becomes more distributed and complex
Solution Approach 1:
The patent combines the electronic control module with the fan motor assembly into an integrated unit, merging previously separate components. This integration simplifies the distributed architecture by consolidating control and actuation functions, reducing the number of separate components while maintaining short cable connections and eliminating the need for complex distributed wiring
3Ease of manufacture
If standard cables are used for power transmission over long distances, then installation is simpler, but electromagnetic screens are required to handle harmonic interference
Solution Approach 1:
The patent extracts the source of harmonic interference by placing the electronic control module directly adjacent to the motor, removing the long cable transmission path that generates and transmits harmonics. This extraction eliminates the need for electromagnetic screens while maintaining installation simplicity, as standard short cables can be used without special shielding requirements
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 solution reduces energy losses, minimizes cable requirements, extends motor life, and ensures efficient air evacuation during emergencies by maximizing power delivery to the motor while reducing harmonic interference and electromagnetic stress.
Implementation Method 1
electronic variable speed drive
Implementation Method 2
thermally insulated metal box
Implementation Method 3
bypass module comprising means for the selection of a connection of the fan to the electric network
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a system and method for electronic control of the rotation speed of a fan impeller, the fan being of the type that is installed on the roofs of highway tunnels. The control system comprises an electronic control system which includes an electronic variable speed drive and a bypass module which includes a means for thermal protection, the electronic control system being mounted on the supporting structure of the fan.