Control method for air conditioner

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Solution Overview

Problem

Air conditioners often experience indoor unit freezing due to low ambient temperatures, leading to poor cooling effects, water leakage, and pipe cracks, which existing control methods fail to adequately address.

Innovation Solution

A control method that adjusts the compressor frequency based on the coil temperature of the indoor unit by setting specific temperature presets to prevent freezing, involving decreased, unchanged, or increased frequency operations, and temporarily stopping the compressor when the coil temperature falls below a certain threshold.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the compressor operates continuously at high frequency to maintain cooling capacity, then cooling efficiency is improved, but the indoor unit coil temperature drops too low causing freezing

Engineering Contradiction:
Improvecooling capacityVSAvoidindoor unit freezing
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The control method continuously monitors the indoor unit coil temperature and uses this feedback to dynamically adjust the compressor frequency. When the coil temperature approaches the freezing point, the system automatically reduces compressor frequency to prevent freezing, and increases frequency when the temperature rises to maintain cooling capacity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The compressor frequency is changed from a static high-frequency operation to a dynamic operation that continuously adapts to the actual coil temperature conditions. The system transitions between different frequency levels (high, medium, low) based on real-time temperature feedback, optimizing both cooling performance and freezing prevention.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the compressor frequency is reduced to prevent freezing, then indoor unit freezing is avoided, but cooling capacity decreases

Engineering Contradiction:
Improveindoor unit freezing preventionVSAvoidcooling capacity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system uses coil temperature feedback to determine when to reduce compressor frequency. Only when the temperature approaches the freezing threshold does the system lower the frequency, and immediately restores high frequency when the temperature recovers, ensuring cooling capacity is maintained whenever possible while preventing freezing only when necessary.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The compressor operates in periodic cycles of high and low frequency based on temperature conditions. The system alternates between high-frequency cooling operation and low-frequency anti-freezing operation, creating a rhythmic pattern that maintains overall cooling capacity while periodically preventing freezing when temperature conditions require it.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3734178B1Control method for air conditioner
Publication Date: 2024.04.10 QINGDAO HAIER AIR CONDITIONING ELECTRONICS CO LTD
  • EP3734178B1 patent drawingFigure 1~2
  • EP3734178B1 patent drawingFigure 3

AI summary

The air conditioner comprises a compressor and an indoor unit. The method comprises: obtaining a coil temperature of the indoor unit; and selectively adjusting the frequency of the compressor according to the coil temperature of the indoor unit. According to the method, the operating frequency of the compressor is adjusted by determining a temperature interval in which the coil temperature of the indoor unit is, so as to avoid the icing of the indoor unit of the air conditioner, thereby effectively solving the icing problem of the indoor unit of the air conditioner, and also improving the operation stability and reliability of the air conditioner.