Blower Motor Phase Switching for Quiet, Energy-Saving Air Conditioning

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Solution Overview

Problem

Conventional air conditioners switch between two-phase and three-phase systems based on fixed threshold values, not adapting to the operating environment, leading to suboptimal energy efficiency and noise/vibration levels.

Innovation Solution

An air conditioner with a controller that adjusts the blower motor's operation between two-phase and three-phase systems based on specific rotational speed thresholds calculated using correction values dependent on power saving, sleeping, and non-power saving modes, allowing adaptive switching according to the operating environment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed threshold value is used for switching between two-phase and three-phase systems, then the switching operation is simple to implement, but it does not adapt to different operating environments leading to suboptimal energy efficiency

Engineering Contradiction:
Improveadaptability to operating environmentVSAvoidcomplexity of switching control
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the switching threshold adaptive rather than fixed. The controller dynamically adjusts the rotational speed threshold for switching between two-phase and three-phase systems based on the current operating mode (power saving mode, sleeping mode, or normal mode). This allows the system to adapt to different operating environments while maintaining manageable complexity through mode-based classification.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of the switching threshold from a fixed value to a variable value that depends on the operating mode. By storing different threshold values in memory for different modes (power saving mode threshold, sleeping mode threshold, normal mode threshold), the system achieves adaptability to different operating conditions without excessive complexity.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the two-phase system is used, then power loss at switching and due to overshoot is reduced, but noise and vibration generated by motor rotation increase

Engineering Contradiction:
Improvepower lossVSAvoidnoise and vibration
Core Design Contradiction:
Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by adjusting the switching threshold based on the operating mode to balance energy efficiency and noise/vibration reduction. In power saving mode, a lower threshold is used to favor two-phase operation for reduced power loss. In sleeping mode, a higher threshold is used to favor three-phase operation for reduced noise and vibration, demonstrating adaptive parameter adjustment to resolve the contradiction.

Inventive Principle:
Principle #35Parameter changes

3Object-generated harmful factors

If the three-phase system is used, then noise and vibration are reduced, but power loss at switching and due to overshoot increases

Engineering Contradiction:
Improvenoise and vibrationVSAvoidpower loss
Core Design Contradiction:
Object-generated harmful factorsVSLoss of energy

Solution Approach 1:

The patent uses dynamics by implementing mode-dependent threshold adjustment. During sleeping mode when noise and vibration are critical, the system dynamically raises the switching threshold to favor three-phase operation. During power saving mode when energy efficiency is prioritized, the threshold is lowered to favor two-phase operation, thus dynamically resolving the contradiction based on current operational requirements.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3450867B1Air conditioner
Publication Date: 2021.09.15 MITSUBISHI ELECTRIC CORP
  • EP3450867B1 patent drawingFigure 1
  • EP3450867B1 patent drawingFigure 2
  • EP3450867B1 patent drawingFigure 3

AI summary

An air conditioner (1A) includes a controller (14A) that controls an inverter (12) on the basis of an instruction received by a receiver (13). The controller (14A) includes: a rotational speed acquisition unit (34) that acquires a specific rotational speed corresponding to a combination of an air volume and an air speed; a correction value acquisition unit (35) that acquires a specific correction value by determining an operation mode, presence or absence of a power saving mode, and presence or absence of a sleeping mode; and a selection unit (39) that selects three-phase operation when the specific rotational speed is lower than a threshold calculated by adding the specific correction value to a fixed value, or selects two-phase operation when the specific rotational speed is higher than or equal to the threshold.