AC Communication Circuit With Transformer Noise Band Exclusion

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Solution Overview

Problem

Existing air conditioning systems face challenges in increasing communication speed while minimizing noise interference in the communication line, which affects the controllability of outdoor and indoor units.

Innovation Solution

The system employs a noise-cut transformer and coupling capacitor to adjust the frequency components of the communication signal, excluding a predetermined frequency band to reduce noise influence, enabling high-speed communication by adjusting the signal level and frequency characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the communication speed in the air conditioning communication line is increased to improve controllability, then the communication efficiency is improved, but the influence of noise from the inverter circuit becomes larger

Engineering Contradiction:
Improvecommunication speedVSAvoidnoise influence
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The communication signal is divided into multiple frequency components, and specific frequency bands corresponding to inverter noise are excluded or attenuated. This segmentation allows the system to transmit high-speed communication signals while avoiding the harmful frequency ranges where inverter noise occurs, thereby resolving the contradiction between communication speed and noise interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different signal processing treatments to different frequency components of the communication signal. By adjusting the characteristics of specific frequency bands (particularly those affected by inverter noise) while maintaining other frequency bands, the system achieves high-speed communication in clean frequency ranges while suppressing noise-affected ranges.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If the communication line is extended to connect multiple indoor and outdoor units, then the system coverage is improved, but the noise influence on communication signal increases

Engineering Contradiction:
Improvesystem coverageVSAvoidnoise influence
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

By segmenting the communication signal into multiple frequency components and excluding noise-affected frequency bands, the system can extend the communication line to connect multiple units without the noise accumulating and degrading the signal quality, thus enabling broader system coverage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces frequency selection and signal processing mechanisms as intermediaries between the communication signal and the noisy communication line. These intermediaries filter out noise frequencies and preserve the integrity of the communication signal over extended line lengths.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3760940B1Air conditioning system
Publication Date: 2023.06.07 DAIKIN INDUSTRIES LTD
  • EP3760940B1 patent drawingFigure 1
  • EP3760940B1 patent drawingFigure 2
  • EP3760940B1 patent drawingFigure 3

AI summary

An air conditioning system (1) includes an outdoor unit (2) and an indoor unit (3) connected to the outdoor unit (2) through an air conditioning communication line (6). The outdoor unit (2) includes: a control unit (11); a compressor (12); a fan (14); a compressor inverter (13); a fan inverter (15); a heat exchanger; and valves of various types. The control unit (11) of the outdoor unit (2) has a coupling capacitor (22) and a noise-cutting transformer (23) which are between a communication circuit (21) and the air conditioning communication line (6).