Indoor AC Controller for Outdoor Unit Power Failure Detection

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Solution Overview

Problem

Conventional air-conditioning systems require a separate hardware component to detect power interruptions from commercial power supplies, which is not feasible without additional hardware.

Innovation Solution

An air-conditioning system with an indoor unit that includes a controller capable of analyzing communication errors to determine power failures in the outdoor unit, using an energization-time error determination unit and connection establishment error determination unit to drive the fan using emergency power supply without additional hardware.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate hardware component is used to detect power interruptions, then the detection reliability is improved, but the device complexity and cost increase

Engineering Contradiction:

Improvepower failure detection reliabilityVSAvoidhardware component quantity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The communication controller performs dual functions: it manages normal communication between indoor and outdoor units, and simultaneously detects power failures by monitoring communication states. This eliminates the need for separate detection hardware while maintaining reliable power failure detection capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses its own communication infrastructure to detect power failures. The communication controller monitors whether communication signals can be transmitted and received, and uses this self-monitoring capability to detect outdoor unit power failures without external assistance.

Inventive Principle:

Principle #25Self-service

2Device complexity

If communication error analysis is used to detect power failures, then the device complexity is reduced, but the measurement precision may be affected

Engineering Contradiction:

Improvehardware component quantityVSAvoidpower failure detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The detection process is segmented into distinct phases: connection establishment phase and normal communication phase. By analyzing communication errors specific to each phase, the system accurately distinguishes between power failures and other communication issues, maintaining high detection precision.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system performs preliminary communication attempts during the connection establishment phase before normal operation begins. By analyzing whether communication errors occur during this preliminary phase specifically, the system can accurately detect power failures before they affect normal operation.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10619875B2Air-conditioning system

Publication Date: 2020.04.14 MITSUBISHI ELECTRIC CORP

AI summary

A controller of an indoor unit included in an air-conditioning system determines whether or not a communication error with the outdoor unit is an energization error that only occurs during an energization time in which electric power is fed from a commercial power supply to the outdoor unit. The controller can also determine whether or not the communication error is a connection establishment error that occurs at a time of establishing a connection with the outdoor unit. Based on determining the cause of the communication error with the outdoor unit, the controller can drive a fan by electric power fed from an emergency power supply.