Induction-Heated Laundry Drum Control for Low-RPM Heat-Spinning

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Solution Overview

Problem

Conventional laundry machines with washing and drying functions lack flexibility in drying options, efficiency in spinning performance, especially at low RPM, and stability, leading to suboptimal performance and user dissatisfaction due to limited heater output and noise issues during midnight operations.

Innovation Solution

A laundry machine equipped with an induction heater for convection heating, allowing users to select between heat-spinning and normal spinning modes, with a control method that varies heater output based on RPM and includes a user interface for diverse drying course selection, enabling efficient spinning and drying even at low RPM and low noise levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the maximum momentary power is limited to protect the laundry machine, then power stability is secured, but the heater output is restricted and heat-spinning efficiency deteriorates

Engineering Contradiction:
Improvepower stabilityVSAvoidheat-spinning efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements dynamic power allocation by continuously monitoring the actual power consumption of the motor during spinning and adjusting the heater output accordingly. The control unit calculates the difference between the maximum momentary power and the actual power consumption, then dynamically adjusts the heater output to utilize the remaining power capacity. This resolves the contradiction by making the power allocation flexible rather than fixed, allowing both motor and heater to operate at optimal levels without exceeding the maximum power limit.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of heater output from a fixed preset value to a variable value that adapts to actual operating conditions. By continuously adjusting the heater output based on real-time power consumption data, the system optimizes the heat-spinning efficiency while maintaining power stability. This parameter change allows the system to achieve better heat-spinning performance without compromising the maximum power limit.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the uppermost limit of heating temperature is preset based on maximum RPM, then system stability is maintained, but additional heating capability is lost at low RPM

Engineering Contradiction:
Improvesystem stabilityVSAvoidheating temperature adaptability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic temperature adjustment by linking the maximum heating temperature to the actual spinning RPM rather than using a fixed preset value. The control unit continuously monitors the spinning RPM and adjusts the heater output to achieve the appropriate heating temperature for that specific RPM level. This allows the system to maintain stability at high RPM while enabling additional heating capability at low RPM, resolving the contradiction between system stability and heating adaptability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of maximum heating temperature from a fixed preset value to a variable parameter that changes based on the spinning RPM. By establishing a dynamic relationship between RPM and maximum heating temperature, the system adapts the heating capability to the actual operating conditions. This allows optimal heat-spinning performance across different RPM levels while maintaining system stability.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the drum is heated at high RPM, then heat-spinning efficiency is improved, but noise and vibration increase

Engineering Contradiction:
Improveheat-spinning efficiencyVSAvoidnoise and vibration
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the operating parameters of heat-spinning by adjusting both the spinning RPM and heating temperature based on the selected mode. In silent mode, the system uses lower RPM combined with optimized heating temperature to achieve effective water content reduction with minimal noise and vibration. In high-speed mode, the system uses higher RPM for faster water removal. This parameter adaptation resolves the contradiction by providing different optimized parameter sets for different operational requirements.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamic parameter adjustment that allows the system to switch between different heat-spinning strategies based on user selection. The control unit dynamically adjusts the RPM and heating temperature parameters to match the selected mode, enabling the system to optimize between heat-spinning efficiency and noise/vibration levels depending on the operational context.

Inventive Principle:
Principle #15Dynamics

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 solution enhances spinning and drying performance by effectively reducing water content, improving efficiency, and reducing noise and vibration, allowing for flexible operation modes, including silent and night modes, while optimizing heater output for better user satisfaction.

Implementation Method 1

an induction heater that is provided in the tub and configured to heat an outer circumferential surface of the drum located in opposite

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a laundry machine which may heat a drum by means of an induction heater

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 3

a motor that is configured to drive so as to rotate the drum

Methodology Applied
Scientific EffectElectromagnetic interaction: Electromagnetic Induction

Implementation Method 4

the spinning means that the water contained in the laundry by using a centrifugal force of the drum rotating at a high rotation speed

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentUS11739470B2Laundry machine having induction heater and control method of the same
Publication Date: 2023.08.29 LG ELECTRONICS INC
  • US11739470B2 patent drawing
  • US11739470B2 patent drawing
  • US11739470B2 patent drawing

AI summary

A laundry machine includes a tub, a drum that is rotatably mounted in the tub, and an induction heater that is provided in the tub and configured to heat an outer circumferential surface of the drum. The laundry machine also includes a motor that is configured to rotate the drum, a user interface comprising a course selection unit that is configured to allow a user to select a course, and an option selection unit that is configured to allow the user to select option information that is related with the course selected. The laundry machine further includes a processor that is configured to control the drum rotation speed and the induction heater. The course selection unit comprises a wash-drying course that performs heat-spinning by default, the heat-spinning being configured to heat the drum by driving the induction heater when the drum rotates.