PCB Power Supply Eliminates Optocouplers for Compressor Control

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Solution Overview

Problem

The use of optocouplers in automotive applications for controlling electrically driven compressors is unreliable, adds bulk and weight, and is expensive, with a limited lifespan, making it inefficient for saving electrical energy when the compressor is stopped.

Innovation Solution

A printed circuit board design that eliminates the need for an isolation component by using a transformer-based switching power supply circuit with detection means to cut off power when a predetermined drop in electrical consumption is detected, allowing the microprocessor to control the power supply directly between voltage sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an optocoupler is used to send control signals across the potential barrier, then isolation between voltage sources is achieved, but the device becomes more complex, bulkier, heavier, and less reliable

Engineering Contradiction:
ImprovereliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the optocoupler component from the system entirely. The control signal transmission function is extracted and integrated directly into the transformer-based power supply circuit, eliminating the need for separate isolation components while maintaining galvanic isolation through the transformer's inherent design

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent combines the power supply function and the control signal transmission function into a single integrated circuit. The transformer serves dual purposes: providing power conversion and enabling control signal transmission across the potential barrier, thereby reducing overall device complexity and component count

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If an optocoupler is used for isolation, then signal transmission across potential barrier is enabled, but additional bulk and weight are added

Engineering Contradiction:
Improveisolation reliabilityVSAvoidweight
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The transformer is designed to perform both power conversion and control signal transmission functions simultaneously. By merging these functions into a single component, the patent eliminates the need for separate optocoupler isolation devices, thereby reducing overall weight while maintaining reliable galvanic isolation

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If an optocoupler is used to maintain isolation, then potential barrier integrity is preserved, but cost increases and lifespan is limited

Engineering Contradiction:
Improveisolation integrityVSAvoidlifespan
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent removes the optocoupler component that has limited lifespan and reliability issues. The isolation function is extracted and implemented through the transformer's inherent galvanic isolation capability, which provides unlimited lifespan and automotive-grade reliability without the degradation issues associated with optocoupler aging

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the expensive, limited-lifespan optocoupler with a more durable, cost-effective transformer-based solution. The transformer provides long-term, reliable isolation without the replacement needs associated with aging optocoupler components

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Use of energy by moving object

If the switching power supply circuit is cut off to save energy, then electrical energy consumption is reduced, but control signal transmission becomes impossible

Engineering Contradiction:
Improveenergy consumptionVSAvoidcontrol capability
Core Design Contradiction:
Use of energy by moving objectVSEase of operation

Solution Approach 1:

The patent implements periodic monitoring of the control signal line to detect when the compressor controller is in standby mode. This allows the system to periodically maintain power supply for control signaling while minimizing overall energy consumption, rather than completely cutting off power which would eliminate control capability

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent uses feedback from the control signal line to detect the operational state of the compressor controller. This feedback mechanism allows the power supply circuit to maintain operation only when control signals are actively being transmitted, automatically reducing power consumption when the controller is in standby while preserving control capability when needed

Inventive Principle:
Principle #23Feedback

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 provides reliable and efficient power management by eliminating the need for optocouplers, reducing bulk, weight, and cost, while ensuring the compressor can be placed on standby without additional components, thereby saving energy.

Implementation Method 1

a switching power supply circuit connecting the first and the second portions, the switching power supply circuit comprising a transformer having a primary and at least one secondary, the primary being connected to the first portion and the secondary being connected to the second portion

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2538514B1Printed circuit board for compressor housing
Publication Date: 2018.08.29 VALEO JAPAN CO LTD
  • EP2538514B1 patent drawingFigure 1~2
  • EP2538514B1 patent drawingFigure 3~4
  • EP2538514B1 patent drawingFigure 5~6

AI summary

The printed circuit board (PCB) (12) has first and second portions (20, 24) including two electronic components (22, 26) whose reference masses are on two voltage sources (14, 16). A third portion (28) is inserted between the first and second portions, and forms a potential barrier. A switching mode power supply (32) i.e. Flyback converter, connects the first and second portions together. A detecting unit (34) detects low power consumption of a microprocessor (30) of the second portion. A cutting unit cuts the switching mode power supply when predetermined low power consumption is detected. An independent claim is also included for a method for controlling a PCB.