Control Electronics Galvanic Isolation Switch Agricultural Vehicle

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Solution Overview

Problem

Existing control electronics for agricultural and forestry vehicles and machines face challenges in achieving cost-effective galvanic isolation between communication and power components, which is essential for preventing crosstalk and meeting international standards like ISO 11783, while maintaining potential freedom and isolating impedance requirements.

Innovation Solution

Incorporating a switch to connect the first and second supply networks, ensuring a minimum isolating impedance when the switch is off, and temporarily closing the switch to establish an electrically conductive connection between the communication network, logic circuit, and loads, utilizing a MOSFET for high isolating impedance, and optionally using a transformer or optocoupler for signal transmission without conductive connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If galvanic isolation is achieved using optocouplers or magnetic couplings, then potential freedom between supply networks is ensured, but device complexity and manufacturing costs increase significantly

Engineering Contradiction:
Improvepotential freedomVSAvoidnumber of signal paths
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the galvanic isolation requirement from the signal transmission path and applies it only to the power supply connections. By separating power supply isolation from signal transmission, the system achieves potential freedom without requiring complex optocouplers or magnetic couplings for each signal path.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The switch serves multiple functions: it enables temporary galvanic isolation during initialization, allows data transmission during operation, and maintains potential freedom between supply networks. This multi-functional approach replaces what would otherwise require separate isolation components for each function.

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

2Ease of manufacture

If a switch is used to connect supply networks temporarily, then manufacturing costs are reduced, but isolating impedance may be compromised during switching transitions

Engineering Contradiction:
Improvemanufacturing costVSAvoidisolating impedance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The switch operates in periodic cycles: closed during initialization to enable data transmission, then opened to restore galvanic isolation. This periodic switching ensures that the system achieves both low-cost implementation and maintained isolating impedance during critical operation phases.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The switch is closed temporarily during the initialization phase before normal operation begins. This preliminary action allows the system to establish communication and synchronize parameters while maintaining the option to restore isolation before critical operations commence.

Inventive Principle:
Principle #10Preliminary action

3Object-affected harmful factors

If ground lines of supply networks converge at a single point, then ground loops are avoided, but system complexity increases due to distributed grounding requirements

Engineering Contradiction:
Improveground loopsVSAvoidgrounding structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The grounding system is segmented into separate ground lines for each supply network that converge only at a single designated point (negative pole of battery). This segmentation prevents ground loops by eliminating alternative current paths while maintaining a structured, manageable grounding architecture.

Inventive Principle:
Principle #1Segmentation

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 approach reduces manufacturing costs and meets the isolating impedance requirements of ISO 11783 standards by providing temporary galvanic isolation during system operation, allowing for efficient data transmission and control while maintaining potential freedom between supply networks.

Implementation Method 1

the switch is set up to connect the first supply network to the second supply network, so that the two supply networks have at least one specified minimum isolating impedance when the at least one switch is in a switched-off state

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 2

optionally using a transformer or optocoupler for signal transmission without conductive connections

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Data Source

PatentEP3292656B1Control electronics for an agricultural or forestry vehicle
Publication Date: 2019.03.20 CONTINENTAL AUTOMOTIVE GMBH
  • EP3292656B1 patent drawingFigure 1
  • EP3292656B1 patent drawingFigure 2
  • EP3292656B1 patent drawingFigure 3

AI summary

The invention relates to control electronics for an agricultural or forestry vehicle or for an agricultural or forestry machine, having power connections at least for a first supply network (4, 46) and a second supply network (56, 57), and having at least one network connection (80), wherein the control electronics contain a communications circuit (70), which is configured for data transmission via the network connection (80) and is supplied via the first supply network (45, 46), and a logic circuit (69), which is coupled with the communications circuit (70) and has at least one control output for controlling an electrical load (84, 85) supplied via the second supply network (56, 57), having at least one switch (77) which is configured to connect the first supply network (45, 46) to the second supply network (56, 57), such that the two supply networks (45, 46, 56, 57) have at least a defined minimum isolation impedance when the at least one switch (77) is switched off. The invention further relates to methods for switching on such control electronics.