Outdoor AC Power Path Switching for Noise-Resistant Air Conditioning

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Solution Overview

Problem

Conventional air conditioning apparatuses face issues with external noise from the commercial AC power supply causing malfunctions and failures in the outdoor-device control unit during standby periods, leading to inefficiencies and reliability concerns.

Innovation Solution

The air conditioning apparatus incorporates a configuration with noise reduction units, relays, and surge-current suppression components to isolate the outdoor device from external noise, ensuring power efficiency and reliability by controlling power supply paths and using noise reduction units with inductive and capacitive reactance to manage inrush and surge currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If power is supplied to the outdoor device during standby period, then the outdoor-device control unit can operate and respond quickly, but external noise from the commercial AC power supply causes malfunctions and failures

Engineering Contradiction:
Improveresistance to external noiseVSAvoidexternal noise from commercial AC power supply
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A noise filter is introduced as an intermediary component between the commercial AC power supply and the outdoor-device control unit. The noise filter blocks external noise from reaching the control unit while allowing power to pass through, thus protecting the control unit from malfunctions and failures during standby operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful external noise is extracted and separated from the power supply path by using a noise filter. This allows the power supply to continue functioning while the noise component is removed, preventing it from causing malfunctions in the control unit.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If power is supplied to the outdoor device during standby period, then the control unit can operate, but reactive power consumption increases

Engineering Contradiction:
Improveoperation readinessVSAvoidreactive power consumption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The power supply to the outdoor-device control unit is made dynamic rather than static. During standby, power is supplied only when necessary (when indoor devices are operating), and the supply is interrupted when not needed. This dynamic control reduces reactive power consumption while maintaining operation readiness when required.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Power supply to the control unit is implemented in a periodic manner rather than continuously. The power is supplied during periods when indoor devices are operating and interrupted during periods when they are not, reducing overall reactive power consumption while ensuring the control unit is available when needed.

Inventive Principle:
Principle #19Periodic action

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 results in a power-efficient and highly resistant air conditioning system that minimizes standby power and reactive power consumption while preventing failures from external noise, ensuring reliable operation and reduced part failure rates.

Implementation Method 1

an air conditioning apparatus according to claim 1 is provided

Methodology Applied
Scientific EffectNoise filtering: Filter (electronic)

Implementation Method 2

using noise reduction units with inductive and capacitive reactance to manage inrush and surge currents

Methodology Applied
Scientific EffectInductive reactance: Inductor

Implementation Method 3

using noise reduction units with inductive and capacitive reactance to manage inrush and surge currents

Methodology Applied
Scientific EffectCapacitive reactance: Capacitance

Data Source

PatentEP3133354B1Air-conditioning apparatus
Publication Date: 2018.08.01 MITSUBISHI ELECTRIC CORP
  • EP3133354B1 patent drawingFigure 1
  • EP3133354B1 patent drawingFigure 2
  • EP3133354B1 patent drawingFigure 3

AI summary

In order to provide an air conditioning apparatus that is power efficient, and is highly resistant to external noise, the air conditioning apparatus includes an outdoor device (2) that is connected to an AC power supply (1), and indoor devices (3A) and (3B) that are connected to the AC power supply (1) through the outdoor device(2), wherein the outdoor device (2) includes a first current path, through which AC power is supplied from the AC power supply (1) to a control-power-supply generation unit (33) through any one of the indoor devices (3A) and (3B), a first outdoor power-feed switching relay (13B), and a second inrush-current suppression resistor (13A), and a second current path, through which AC power is supplied from the AC power supply 1 to the control-power-supply generation unit (33) through a first noise reduction unit (11), a second outdoor power-feed switching relay (13D), and a surge-current suppression resistor (13E), and when there is a possibility for an inrush current to the control-power-supply generation unit (33) to be generated, the outdoor device (2) supplies AC power of the AC power supply (1) to the control-power-supply generation unit (33) through the first current path, and when there is not a possibility for an inrush current to the control-power-supply generation unit (33) to be generated, the outdoor device (2) supplies AC power of the AC power supply (1) to the control-power-supply generation unit (33) through the second current path.