Three-Wire Air Conditioner Relay Control for Low Standby Power

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Solution Overview

Problem

Existing air conditioners consume power continuously in standby mode due to constant communication between indoor and outdoor units, leading to increased energy consumption and requiring additional cores in connecting cables, which complicates control without increasing cable count.

Innovation Solution

An air conditioner design utilizing a three-core cable with a power line, common line, and signal line, where an outdoor activation relay disconnects the power line and signal line in standby mode, reducing power consumption by cutting off utility power between the signal line and common line.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If constant communication is maintained between indoor and outdoor units in standby mode, then communication readiness is improved, but standby power consumption increases

Engineering Contradiction:
Improvecommunication readinessVSAvoidstandby power consumption
Core Design Contradiction:
ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The patent implements periodic action by switching the communication circuit between energized and non-energized states. In standby mode, the power relay opens to non-energize the communication circuit, eliminating continuous power consumption. When operation is required, the relay closes to energize the circuit for communication. This periodic activation resolves the contradiction between maintaining communication readiness and reducing standby power consumption.

Inventive Principle:
Principle #19Periodic action

2Use of energy by stationary object

If power relay is used to non-energize communication circuit in standby mode, then standby power consumption is reduced, but control capability is lost

Engineering Contradiction:
Improvestandby power consumptionVSAvoidcontrol capability
Core Design Contradiction:
Use of energy by stationary objectVSEase of operation

Solution Approach 1:

The patent applies preliminary action by pre-positioning the power relay in an open state during standby mode. This preliminary configuration allows the system to immediately energize the communication circuit when operation is required, without delay. The relay's pre-set state enables rapid transition from power-saving mode to full operational mode, maintaining control capability while reducing standby consumption.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If three core cable is used for connection, then cable simplicity is maintained, but control flexibility is limited

Engineering Contradiction:
Improvecable structureVSAvoidcontrol flexibility
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements universality by enabling the three-core cable to serve multiple functions: power transmission and communication signal transmission. The power relay controls the utilization of these cores dynamically - energizing communication cores when needed while keeping them dormant during standby. This multi-functional use of the same cable structure provides both cable simplicity and operational flexibility without requiring additional cables or complex wiring.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 configuration reduces standby power consumption and allows control without increasing the number of connecting cable cores, enabling efficient operation and communication between indoor and outdoor units.

Implementation Method 1

an outdoor activation relay configured to open and close a connection between the power line and the signal line

Methodology Applied
Scientific EffectRelay: Relay

Data Source

PatentEP2241831B1Air conditioner with reduced standby power consuption of the outdoor unit on the basis of a three wire cable connection between indoor and outdoor unit
Publication Date: 2018.04.25 MITSUBISHI ELECTRIC CORP
  • EP2241831B1 patent drawingFigure 1
  • EP2241831B1 patent drawingFigure 2
  • EP2241831B1 patent drawingFigure 3

AI summary

To obtain an air conditioner which is capable of reducing standby condition power consumption. An indoor unit (2) includes an outdoor activation relay (22) configured to open and close a connection between a power line (8) and a signal line (16), and an indoor control unit (5) configured to operate the outdoor activation relay (22) and supply the utility power (7) between the signal line (16) and a power signal common line (9), and the indoor control unit (5) opens a connection between the power line (8) and the power signal common line (9) in a standby condition.