Two-Wire Power and Communication for Air Conditioner Indoor Units
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Solution Overview
Problem
Conventional air conditioners with wired controllers require a large number of lines for installation, leading to increased costs and the likelihood of incorrect line connections, which can cause communication malfunctions, especially in multi-type systems where crosstalk and installation difficulties are significant.
Innovation Solution
The air conditioner employs a communication method where high-frequency signals, modulated into sinusoidal, sawtooth, or triangular waveforms, are transmitted through two lines, allowing for power supply and communication between indoor units and a wired controller, with components like capacitors and inductors separating power and communication signals, and power detectors ensuring correct power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If four lines (two power lines and two communication lines) are used to connect indoor unit and outdoor unit, then power supply and communication can be performed, but the number of lines increases leading to increased installation costs and likelihood of incorrect connections
Solution Approach 1:
The patent combines power transmission and communication functions into a single two-wire system. The same two lines that carry power between the indoor and outdoor units also carry communication signals, eliminating the need for separate communication lines. This merging reduces the total number of lines from four to two while maintaining both power supply and communication capabilities.
Solution Approach 2:
The two lines connecting the indoor and outdoor units serve multiple functions simultaneously: they provide power transmission, power detection, and bidirectional communication. This multi-functionality allows the system to perform several operations through a single connection interface, reducing installation complexity and the number of components required.
2Adaptability or versatility
If a large number of lines are used in multi-type air conditioners, then power and communication can be extended to multiple units, but crosstalk between lines increases making communication unstable
Solution Approach 1:
By merging power and communication into the same two-wire system, the patent eliminates separate communication lines that would be susceptible to crosstalk. The communication signals are superimposed on the power lines, and the differential signaling method used is inherently resistant to electromagnetic interference and crosstalk from other lines in the system.
Solution Approach 2:
The patent uses differential signaling as an intermediary method to transmit communication signals through the power lines. This differential mode transmission acts as a mediator that converts single-ended signals into balanced differential signals, which are naturally immune to common-mode noise and crosstalk, thereby enabling stable communication even in multi-unit configurations.
3Reliability
If service technician individually connects four lines between indoor unit and outdoor unit, then complete connections can be established, but installation time and likelihood of incorrect connections increase
Solution Approach 1:
The patent merges the connection requirements from four separate lines to just two lines. Service technicians only need to connect two wires between the indoor and outdoor units, reducing the number of connection points from four to two. This simplification directly reduces installation time and minimizes the opportunities for incorrect connections while maintaining full 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 solution reduces the number of lines needed, minimizes electromagnetic interference, and ensures stable communication and power supply even with incorrect line polarities, simplifying installation and reducing repair costs by separating power and communication signals effectively.
Implementation Method 1
a communication signal is transmitted after being modulated into a high-frequency communication signal when communication is performed between one or a plurality of indoor units and a wired controller
Implementation Method 2
separate a received signal into a high-frequency communication signal and a power signal, and pass only the separated high-frequency communication signal
Implementation Method 3
a power transmitter to output power to the two lines to supply the power to the wired controller
Data Source
Figure 1A~1B
Figure 2
Figure 3(a)~3(d)
AI summary
An air conditioner includes at least one indoor unit and a wired controller connected to the indoor unit through two lines to receive power from the indoor unit and to perform data communication with the indoor unit. Each of the indoor unit and the wired controller includes a communication unit that modulates a low-frequency communication signal into a high-frequency communication signal and transmits the high-frequency signal and demodulates a received high-frequency signal into a low-frequency signal. When a plurality of indoor units and a wired controller perform communication, a communication signal is transmitted after being modulated into a high-frequency signal and linking the high-frequency signal with DC power. This reduces the inductance of an inductor required to separate the linked high-frequency signal into DC power and a communication signal and the capacitance of a capacitor required to link the signal with DC power, reducing PCB size and inductor and capacitor costs.