Air Conditioner Motor Control for Compressor Overload Prevention

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Solution Overview

Problem

Air conditioners face the challenge of motor overload due to mismatched operational conditions between the compressor and fan motors, leading to potential circuit protection issues and unnoticed abnormal operations.

Innovation Solution

A motor controlling method and apparatus that temporarily stops the compressor motor if its operation frequency exceeds a certain threshold and the fan motor's velocity is lower than a specified value for a defined period, with optional error warnings or complete shutdown if the compressor is stopped excessively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the compressor motor operates at high frequency continuously, then cooling efficiency is improved, but motor overload and circuit protection issues occur when fan motor velocity is insufficient

Engineering Contradiction:
Improvecooling efficiencyVSAvoidmotor overload protection
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The control device continuously monitors the operational status of both the compressor motor and fan motor, using feedback signals to detect abnormal conditions. When the fan motor velocity is insufficient while the compressor motor operates at high frequency, the system receives feedback indicating this mismatch and automatically adjusts the compressor motor operation to prevent overload, thereby maintaining both cooling efficiency and system reliability.

Inventive Principle:
Principle #23Feedback

2Reliability

If the compressor motor is temporarily stopped under abnormal conditions, then circuit elements are protected, but continuous operation is required for optimal cooling performance

Engineering Contradiction:
Improvecircuit protectionVSAvoidcooling performance
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The control device implements preliminary protective action by detecting abnormal operational conditions (insufficient fan motor velocity combined with high compressor motor frequency) before they cause motor overload or circuit damage. By preemptively stopping or adjusting the compressor motor operation under these detected abnormal conditions, the system prevents harmful effects while minimizing disruption to cooling performance, as the stoppage is temporary and condition-specific rather than continuous.

Inventive Principle:
Principle #9Preliminary anti-action

3Productivity

If abnormal operations are not detected, then continuous operation is maintained, but overload damage occurs unnoticed

Engineering Contradiction:
Improvecontinuous operationVSAvoidunnoticed overload damage
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The control device employs continuous feedback monitoring of both compressor motor and fan motor operational parameters. This feedback mechanism enables the system to detect abnormal conditions (such as insufficient fan velocity during high-frequency compressor operation) in real-time, allowing for immediate corrective action before overload damage occurs. The feedback system ensures that continuous operation is maintained only under normal conditions, while automatically intervening when abnormality is detected.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2056033B1Method for controlling motor of air conditioner and motor controller of the same
Publication Date: 2015.02.25 LG ELECTRONICS INC
  • EP2056033B1 patent drawingFigure 1
  • EP2056033B1 patent drawingFigure 2
  • EP2056033B1 patent drawingFigure 3(a)~3(b)

AI summary

A motor controlling method and apparatus of an air conditioner are disclosed. It is checked whether or not an operation frequency of a compressor motor is the same as or greater than a certain frequency and it is also checked whether or not a detected velocity of a fan motor is the same as or lower than a certain velocity during a certain time period. If the operation frequency is the same as or grater than the certain frequency and the detected velocity is the same as or lower than the certain velocity during a certain time period, the compressor motor is temporarily stopped. Because the compressor motor operates according to operational conditions of the fan motor, an overload can be prevented.