Induction Heating Control Device for Individual Temperature Regulation

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Solution Overview

Problem

Existing control devices for induction heating units cannot individually control the temperature rise on both sides of a material being heated, as they apply the same voltage to both units, leading to an inability to prevent abnormal mutual induction phenomena.

Innovation Solution

A control device that synchronizes the operation frequency and phase of the output currents between a master and slave inverter, allowing for individual control of temperature rise on each side by using reverse magnetic flux directions in C-shaped heating units and forming specific loop circuits to prevent ground currents and arcs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the same voltage is applied to both induction heating units, then the control device is simple, but individual control of temperature rise on each side is impossible

Engineering Contradiction:
Improvecontrol device complexityVSAvoidindividual temperature control capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent divides the control system into two independent inversioners (first inverter and second inverter), each capable of independently controlling its respective induction heating unit. This segmentation allows individual temperature control on each side of the material while maintaining relatively simple overall device architecture through modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic control by allowing each inverter to independently adjust its output voltage and phase angle in real-time. The control unit can dynamically modify operating parameters of each inverter based on temperature feedback from temperature detection units, enabling precise individual temperature control.

Inventive Principle:
Principle #15Dynamics

2Area of stationary object

If induction heating units are arranged in the vicinity of both side portions, then heating coverage is improved, but abnormal mutual induction phenomenon occurs

Engineering Contradiction:
Improveheating coverage areaVSAvoidabnormal mutual induction
Core Design Contradiction:
Area of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by introducing a phase angle control mechanism that proactively prevents abnormal mutual induction. The control unit adjusts the phase angle between the two inversioners to ensure that magnetic flux from one inverter does not induce harmful currents in the other inverter, thereby eliminating the harmful effect before it can occur.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The patent uses the phase angle difference as an intermediary parameter to mediate between the two induction heating units. By controlling the phase angle relationship between the inversioners, the system enables both units to operate simultaneously without causing harmful mutual induction, effectively using phase control as a mediating mechanism.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If phases of current are synchronized, then abnormal mutual induction is prevented, but individual control of power supplied to each unit is impossible

Engineering Contradiction:
Improveprevention of abnormal mutual inductionVSAvoidindividual power control capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic phase angle control where the control unit can independently adjust the phase angle of each inverter relative to the other. This dynamic adjustment allows the system to prevent abnormal mutual induction by optimizing phase relationships while simultaneously enabling individual power control through independent voltage and phase modulation of each inverter.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes multiple parameters simultaneously - both voltage magnitude and phase angle - for each inverter independently. This multi-parameter control allows the system to maintain reliable operation by preventing mutual induction through phase angle optimization while achieving individual power control through independent voltage adjustment of each inverter.

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

Enables individual control of temperature rise on both sides of the material while preventing abnormal mutual induction, ensuring efficient heating without arc formation or power inefficiencies.

Implementation Method 1

a first C-shaped heating unit (5) and a second C-shaped heating unit (6) which are arranged in the vicinity of both side portions of the material (1) to be heated, respectively

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 2

phases of current of the two induction heating units are synchronized. For this reason, an abnormal mutual induction phenomenon does not occur between the two induction heating units

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2890217B1Control device for induction heating units
Publication Date: 2020.01.08 TOSHIBA MITSUBISHI ELECTRIC IND SYST CORP
  • EP2890217B1 patent drawingFigure 1
  • EP2890217B1 patent drawingFigure 2
  • EP2890217B1 patent drawingFigure 3

AI summary

Provided is a control device for induction heating units which is capable of individually controlling amounts of temperature rise in one side portion and the other side portion of a material to be heated while preventing the occurrence of an abnormal mutual induction phenomenon between two induction heating units. To this end, the control device includes: a master frequency control part that sets an operation frequency of a master inverter, which drives a master C-shaped induction heating unit provided on one side of a material to be heated, so that a phase of an output voltage and a phase of an output current from the master inverter are synchronized; a slave frequency control part that synchronizes an operation frequency of a slave inverter, which drives a slave C-shaped induction heating unit provided on the other side of the material to be heated, with the operation frequency of the master inverter; a slave current phase control part that synchronizes a phase of an output current from the slave inverter with the phase of the output current from the master inverter; a master voltage control part which sets a pulse width of the output voltage from the master inverter; and a slave voltage control part which sets a pulse width of an output voltage from the slave inverter.