IGBT Power Controller for Metallic Workpiece Heating

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Solution Overview

Problem

The Joule effect is underutilized in industrial heating due to safety concerns and inefficiencies, particularly in heat treatment of metallic workpieces, as it often results in energy losses and potential damage from short circuits or improper contact, requiring precise conductor management and protection.

Innovation Solution

An electrical/electronic equipment that utilizes IGBT switching in a power controller to achieve precise control of electric current frequency and voltage for direct heating of metallic workpieces, allowing for real-time temperature monitoring and automatic adjustments, enabling efficient and rapid heating with minimal energy loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If Joule effect is applied for heating metallic workpieces, then heating efficiency is improved, but safety risks increase due to short circuits and bad contacts

Engineering Contradiction:
Improveheating efficiencyVSAvoidsafety
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent introduces an intermediate coupling system consisting of two separate coils (primary and secondary) connected through magnetic coupling rather than direct electrical contact. This intermediary magnetic field transfer mechanism eliminates the need for direct conductor contact with the workpiece, thereby preventing short circuits and bad contacts while maintaining efficient energy transfer for heating

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the traditional direct electrical contact system (mechanical/conductor-based) with an electromagnetic induction system. Instead of using conductors that physically touch the workpiece, the system uses time-varying magnetic fields to induce currents within the workpiece, eliminating mechanical contact risks while achieving the desired heating effect

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

2Reliability

If traditional heating methods are used, then safety is maintained, but heating speed decreases

Engineering Contradiction:
ImprovesafetyVSAvoidheating speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent employs periodic alternating current through the primary coil to generate time-varying magnetic fields. This periodic action induces corresponding periodic currents in the workpiece, creating continuous and efficient heating without the safety risks of direct contact, thereby achieving both high heating speed and safety

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent controls heating parameters (frequency, amplitude, duration) of the alternating current to optimize heating efficiency. By adjusting these parameters, the system achieves rapid heating rates while maintaining safe operating conditions through non-contact electromagnetic coupling

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If direct electrical contact heating is used, then equipment complexity is reduced, but energy losses increase

Engineering Contradiction:
Improveequipment complexityVSAvoidenergy losses
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent uses magnetic field coupling as an intermediary between the power source and the workpiece. This intermediate magnetic coupling mechanism enables efficient energy transfer without direct electrical contact, reducing energy losses from contact resistance and short circuits while managing system complexity through standardized electromagnetic components

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The equipment achieves rapid and homogeneous heating of metallic workpieces up to 400°C/sec, outperforming induction and radiation heating methods, with all energy being effectively converted into heat, ensuring safe and efficient processing.

Implementation Method 1

The electric current, when crossing a conductor, causes an increase in temperature that can be calculated by 'Joule's Law', also known as Joule effect or thermal effect

Methodology Applied
Scientific EffectJoule effect: Joule Heating

Data Source

PatentEP3376824B1Electrical/electronic control equipment for heating metallic workpieces
Publication Date: 2019.11.13 AETHRA SISTEMAS AUTOMOTIVOS
  • EP3376824B1 patent drawingFigure 1~2
  • EP3376824B1 patent drawingFigure 3

AI summary

The patent relates to an electrical/electronic control equipment (1) for heating workpieces (5) powered by the electrical power grid (R) and comprising the following parts: an adjustable power driver (2) formed by a rectifier circuit (21), a filter (22), a changeover circuit (23) and a microprocessor control unit (24); a heating and data acquisition controller (3), a power transformer (4). This adjustable power driver generates voltages and frequencies, which may be either three-phase and/or single-phase, adjustable through various set parameters, for the purpose of controlling the heating process. The heating and data acquisition controller is a microprocessor device containing: inputs in the form of sensors (32), a processing unit, outputs and an HMI ("Human-Machine Interface"). The power transformer (4) has specific characteristics, the secondary winding being different from the primary winding, and is cooled through extruded cavities in the secondary core, through which cooled water (43) flows.