Fan Motor Current Feedback for Constant Air Volume Control

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Solution Overview

Problem

Conventional air conditioners struggle to maintain constant air volume control due to variations in supply voltage, which can affect the static pressure and fan motor RPM, leading to inconsistent air volume delivery.

Innovation Solution

An air conditioner system that includes a power supply, a driving mechanism to adjust motor driving voltage based on a duty value, a current detector, a storage for static pressure and air volume data, and a motor controller that calculates and adjusts the fan motor RPM to maintain constant air volume regardless of supply voltage changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the fan motor RPM is controlled based on static pressure measurement, then air volume can be adjusted, but constant air volume cannot be maintained when supply voltage varies

Engineering Contradiction:
Improveair volumeVSAvoidair volume consistency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system uses current detection as feedback to dynamically adjust fan motor RPM. The controller detects the current value input to the fan motor and uses this feedback signal to calculate and adjust the RPM, ensuring constant air volume delivery even when supply voltage fluctuates. This closed-loop feedback mechanism resolves the contradiction by making air volume delivery reliable despite voltage variations.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes the control parameter from static pressure-based RPM control to current-based RPM control. By detecting current values and using them to calculate target RPM, the system adapts to supply voltage variations and maintains consistent air volume. This parameter change enables the system to achieve both air volume adjustment and constant air volume delivery under varying conditions.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the fan motor RPM is varied according to static pressure, then air volume can be controlled, but the control is affected by supply voltage changes

Engineering Contradiction:
Improveair volume controlVSAvoidvoltage variation adaptation
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The system changes the control parameter from static pressure to current detection. The controller detects current values input to the fan motor and uses this parameter to calculate target RPM, making the control system adaptable to different supply voltages while maintaining ease of air volume control.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system applies local quality by using current detection specifically at the fan motor input to obtain voltage-adaptive control information. This localized measurement provides the adaptability needed to handle voltage variations while maintaining simple air volume control operation.

Inventive Principle:
Principle #3Local quality

3Device complexity

If conventional current information based on constant supply voltage is used, then control is simple, but setting air volume cannot be provided when supply voltage changes

Engineering Contradiction:
Improvecontrol systemVSAvoidsupply voltage adaptation
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The system uses current value as the control parameter instead of relying on assumptions of constant supply voltage. This simple parameter change enables the control system to adapt to voltage variations without increasing complexity, as the current detection and基于current的RPM calculation maintain operational simplicity while providing voltage adaptability.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3881010B1Air conditioner of fan motor and operating method thereof
Publication Date: 2025.04.30 LG ELECTRONICS INC
  • EP3881010B1 patent drawingFigure 1a~1b
  • EP3881010B1 patent drawingFigure 2~3
  • EP3881010B1 patent drawingFigure 4

AI summary

The present disclosure is to provide an air conditioner, capable of performing constant air volume control regardless of the variation in a supply voltage and a method for operating the same.