Induction-Heated Laundry Drum Control to Prevent Lifter Overheating

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Solution Overview

Problem

Laundry treatment apparatuses using induction heating face inefficiencies and safety concerns due to overheating, particularly in the drum's lifter area, where heat is not effectively transferred to laundry, leading to energy waste and potential damage.

Innovation Solution

A laundry treatment apparatus with an induction heating system that includes a temperature sensor on the tub's inner peripheral surface to indirectly measure the drum's temperature, an induction module positioned on the tub's quadrants to evenly heat the drum, and a controller that adjusts heat output based on the lifter's position and drum rotation speed to prevent overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If induction heating is applied to the drum, then heating efficiency is improved, but overheating of the lifter may occur causing safety issues

Engineering Contradiction:
Improveheating efficiencyVSAvoidsafety
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The controller preemptively reduces or stops induction heating when it detects that the lifter is positioned in the heating zone, preventing overheating before it occurs. This is achieved by monitoring drum rotation and coordinating heating cycles with lifter position to anticipate potential overheating conditions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors drum rotation and lifter position, using this feedback to dynamically adjust the induction heating operation. The controller modulates heating power based on real-time positional information, creating a closed-loop control system that prevents lifter overheating while maintaining efficient heating when the lifter is not in the heating zone.

Inventive Principle:
Principle #23Feedback

2Use of energy by moving object

If the drum rotates slowly, then heat transfer to laundry is improved, but heating efficiency decreases due to longer heating time

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidheating time
Core Design Contradiction:
Use of energy by moving objectVSLoss of time

Solution Approach 1:

The system dynamically adjusts the induction heating power based on the drum's rotation speed. When the drum rotates slowly, the controller increases heating power to compensate for reduced heat transfer, maintaining overall heating efficiency without requiring extended heating periods.

Inventive Principle:
Principle #15Dynamics

3Loss of time

If the drum rotates quickly, then heating time is reduced, but heat transfer to laundry becomes insufficient

Engineering Contradiction:
Improveheating timeVSAvoidheat transfer efficiency
Core Design Contradiction:
Loss of timeVSUse of energy by moving object

Solution Approach 1:

The controller dynamically modulates induction heating power in response to drum rotation speed variations. When rotation speed increases, the system adjusts heating parameters to maintain effective heat transfer, ensuring that faster rotation does not compromise heating performance.

Inventive Principle:
Principle #15Dynamics

4Productivity

If induction heating is continuously applied, then heating performance is maximized, but energy waste occurs in the lifter area

Engineering Contradiction:
Improveheating performanceVSAvoidenergy waste
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The system implements periodic heating cycles synchronized with drum rotation, applying induction heating only during periods when the heating zone is clear of the lifter. This periodic operation maintains effective heating performance while eliminating energy waste that would occur from continuously heating the lifter area.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The controller preemptively interrupts or reduces heating before the lifter enters the heating zone, preventing unnecessary energy consumption in the lifter area while maintaining overall heating effectiveness through timely resumption of heating when the lifter moves away.

Inventive Principle:
Principle #10Preliminary action

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 enhances safety by preventing lifter overheating, improves energy efficiency by optimizing heat distribution, and ensures reliable temperature control, maintaining the drum's stability and performance.

Implementation Method 1

an induction module (70) provided to generate an electromagnetic field so as to heat the drum (30)

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 2

a temperature sensor (60) mounted on an inner peripheral surface of the tub (20) to sense a temperature of air between the inner peripheral surface of the tub (20) and an outer peripheral surface of the drum (30)

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3447181B1Laundry treatment apparatus and method of controlling the same
Publication Date: 2021.09.29 LG ELECTRONICS INC
  • EP3447181B1 patent drawingFigure 1
  • EP3447181B1 patent drawingFigure 2
  • EP3447181B1 patent drawingFigure 3

AI summary

Disclosed is a laundry treatment apparatus, which directly heats a drum accommodating laundry and is enhanced in efficiency and safety. The laundry treatment apparatus includes a tub, a drum formed of a metal material and rotatably provided inside the tub to accommodate laundry, an induction module spaced apart from a circumferential surface of the drum to heat the circumferential surface of the drum via a magnetic field that is generated when current is applied to a coil, a lifter provided in the drum to move the laundry inside the drum when the drum rotates, a temperature sensor provided to sense a temperature of the drum, and a module controller configured to control an output of the induction module so as to control an amount of heat generated from the circumferential surface of the drum. The module controller controls the amount of heat based on the temperature sensed by the sensor.