Electrical device
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Solution Overview
Problem
Air conditioners with inverter devices experience switching noise leakage into power supplies, degrading communication signal quality and causing malfunctions, especially when separate boards communicate and transmit power between them.
Innovation Solution
A capacitor is connected between the DC power output conductor and the metal part of the housing, specifically on the negative or positive potential side, to reduce switching noise in the power supply without affecting communication signal quality between separated boards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a capacitor is connected between the communication line and the metal bottom plate to reduce switching noise leaking into the power supply, then the switching noise reduction is improved, but the communication signal quality deteriorates
Solution Approach 1:
The patent divides the noise filtering function into two separate capacitors: one capacitor connects between the communication line and the metal bottom plate to filter switching noise, while another capacitor connects between the power supply line and the metal bottom plate to maintain power supply stability. This segmentation allows each capacitor to perform its specific function without interfering with the other, thus reducing switching noise while maintaining communication signal quality.
Solution Approach 2:
The metal bottom plate serves as an intermediary ground reference that both capacitors connect to. By using the metal bottom plate as a common reference point, the patent creates separate noise filtering paths for the communication line and power supply line, allowing switching noise to be shunted to ground without affecting the communication signal integrity.
2Adaptability or versatility
If separate boards are used for power conversion and communication functions, then the functional separation is improved, but the switching noise mixing into communication lines increases
Solution Approach 1:
The patent extracts the noise filtering function from the communication board and implements it on the power conversion board by connecting a capacitor between the communication line and the metal bottom plate. This extraction allows the communication board to focus on communication functions while the power conversion board handles both power conversion and noise filtering, preventing switching noise from mixing into communication lines despite functional separation.
Solution Approach 2:
The metal bottom plate acts as an intermediary ground that provides a common reference potential between the power conversion board and communication board. By connecting the capacitor between the communication line and the metal bottom plate, the patent creates a noise filtering path that prevents switching noise generated on the power conversion board from coupling into the communication line, maintaining signal integrity despite physical separation of functions.
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 effectively reduces switching noise in the power supply, preventing signal degradation and board malfunctions while maintaining communication integrity between boards.
Implementation Method 1
a capacitor that is connected between a conductor to which DC power output to the first communication module from the first isolated conversion circuit is supplied and the metal part of the housing
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
An electrical device (90) that is supplied with power from a power supply (4) and performs communication via a communication line (16) between a first board (28) and second board (29) that are separated. The first board (28) is housed in a housing (22) including metal part (3). The electrical device (90) includes a power converter circuit (45), a communication module (10), an isolated conversion circuit (12) that supplies DC power to the communication module (10), which are mounted on the first board (28), and includes a communication module (11) that is mounted on the second board (29) in the housing (22) or in another housing (23) and communicates with the communication module (10). The electrical device (90) includes a capacitor (17) connected between the metal part (3) of the housing (22) and a conductor to which DC power output from the isolated converter circuit (12) to the communication module (10) is supplied, the conductor being a conductor on the negative potential side serving as a voltage reference or a conductor on the positive potential side which is at a higher potential than the negative potential side.