Isolated I/O Output Module for Low-Dissipation DC Signal Control

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Solution Overview

Problem

Industrial control systems face challenges in efficiently managing power dissipation and isolation for DC signal control, particularly in I/O modules, where large voltage dropping resistors are needed to handle power dissipation and prevent faults, leading to heat management issues and potential damage from external contaminants.

Innovation Solution

The use of a magnetic coupling-based isolated source of field-side power, employing field effect transistors and transformer-coupled isolators to provide rapid and controlled power transfer, allowing for low impedance driving and efficient turn-off times, thereby reducing power dissipation and enhancing reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If voltage dropping resistors are used to convert high voltages to lower voltage for field-side circuitry, then power dissipation is handled, but the resistors become physically large and generate heat requiring spacing for heat dissipation

Engineering Contradiction:
Improvepower dissipationVSAvoidresistor size
Core Design Contradiction:
Loss of energyVSArea of stationary object

Solution Approach 1:

The patent replaces the conventional voltage dropping resistor with a magnetic isolator that uses magnetic coupling to transfer power. This substitution eliminates the need for large physical resistors by using electromagnetic fields instead of resistive heating, thereby solving the contradiction between handling power dissipation and maintaining compact size.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the operating parameters by using magnetic coupling efficiency to achieve high power transfer with minimal losses, rather than relying on resistive voltage dropping. This parameter change allows for compact power conversion without the heat dissipation issues of traditional resistors.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If voltage dropping resistors are used to handle power dissipation, then the necessary power dissipation is achieved, but the resistors must be spaced apart to aid in dissipating incident heat

Engineering Contradiction:
Improvepower dissipationVSAvoidspacing requirements
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The magnetic isolator replaces the mechanical spacing requirement with an electromagnetic solution. The magnetic coupling mechanism allows for efficient power transfer without the need for physical spacing, thereby reducing device complexity while maintaining effective power dissipation management.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Loss of energy

If magnetic coupling is used for isolated power transfer, then power dissipation is reduced and reliability is improved, but rapid turn-off capability must be achieved

Engineering Contradiction:
Improvepower dissipationVSAvoidturn-off time
Core Design Contradiction:
Loss of energyVSSpeed

Solution Approach 1:

The patent optimizes the magnetic isolator parameters to achieve both low power dissipation and rapid turn-off capability. By carefully selecting magnetic material properties and circuit parameters, the system achieves efficient power transfer with minimal losses while maintaining fast switching response times.

Inventive Principle:
Principle #35Parameter changes

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 enables substantial isolated power transfer with rapid turn-off capabilities, improving the reliability and efficiency of I/O modules in industrial control systems by minimizing heat dissipation and preventing damage from faults, while allowing for flexible control of AC and DC signals.

Implementation Method 1

at least one transformer-coupled isolator receiving input electrical power referenced to a second signal isolated with respect to the second signal to provide output electrical power referenced to the first signal of floating with respect to the second signal

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

at least one field effect transistor having a source and drain in series between the terminals to control current flow through the terminals according to a first signal received by a gate of the field effect transistor

Methodology Applied
Scientific EffectElectric field control: Electric Field

Data Source

PatentEP3618279B1Output module and corresponding method for industrial control
Publication Date: 2022.11.30 ROCKWELL AUTOMATION TECH INC
  • EP3618279B1 patent drawingFigure 1~2
  • EP3618279B1 patent drawingFigure 3
  • EP3618279B1 patent drawingFigure 4

AI summary

An I/O circuit for use with an industrial controller provides a transformer coupled isolator (104) communicating between a controller and a field-side of the I/O circuit (102) for driving a field effect transistor (142). The circuit is arranged to output power at the field side of the isolator (104) derived from an input power at the controller side of the isolator (104).