Dual Control Board Power Sharing to Reduce AC-DC Converter Duplication

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Solution Overview

Problem

The provision of multiple control boards in air conditioners necessitates a power source circuit with increased components, including noise filters and AC-DC converters, which complicates the system.

Innovation Solution

A control device design that eliminates the need for noise filters and AC-DC converters on secondary control boards, using a common case to house both control boards and employing a communication circuit with a bypass circuit and current signal for communication, allowing independent operation and power-saving modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple control boards are provided in a single air conditioner apparatus, then additional functions can be achieved, but the number of power source circuit components increases

Engineering Contradiction:
Improveadditional functionsVSAvoidnumber of power source circuit components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The first control board is designed to serve multiple functions: it acts as both a control board and a power source board. The power source circuit on the first control board supplies power not only to itself but also to the second control board, eliminating the need for duplicate power source components on the second board.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

Instead of providing a complete copy of the power source circuit on each control board, the patent uses a simplified communication circuit on the second board that copies only the essential control functionality while relying on the first board's power source circuit.

Inventive Principle:
Principle #26Copying

2Reliability

If each control board has its own power source circuit, then each board can operate independently, but the total number of components increases

Engineering Contradiction:
Improveindependent operationVSAvoidtotal number of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The power source functionality is merged into the first control board, which then serves as a shared power source for the entire system. This consolidation maintains system reliability while reducing the total component count by eliminating redundant power source circuits.

Inventive Principle:
Principle #5Merging (Combining)

3Volume of moving object

If control boards are placed close together in a common case, then space is saved, but noise interference may increase

Engineering Contradiction:
Improvespace utilizationVSAvoidnoise interference
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

A shield plate is introduced as an intermediary element between the first and second control boards. This shield plate acts as a barrier to electromagnetic noise while allowing the boards to remain in close proximity for efficient space utilization.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4421398B1Control device and air conditioning device
Publication Date: 2025.08.13 DAIKIN INDUSTRIES LTD
  • EP4421398B1 patent drawingFigure 1
  • EP4421398B1 patent drawingFigure 2
  • EP4421398B1 patent drawingFigure 3

AI summary

A control device includes a first control board connected with an AC power source and equipped with a first control unit, and a second control board provided separately and different from the first control board and equipped with a second control unit. The first control board includes a noise filter, an AC-DC converter configured to generate DC voltage from AC voltage, and DC output wiring configured to allow the DC voltage to be used in the board and also supply the DC voltage to outside the board. The second control board is supplied with DC voltage from the DC output wiring.