Heat Pump Dryer Inverter Compressor Control for Quick Initial Heating

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Solution Overview

Problem

Conventional dryers face inefficiencies in supplying heated air during the initial driving period, particularly in 'Quick driving courses', where the heat pump's compression efficiency is compromised due to fixed velocity compressors, leading to prolonged drying times and reduced efficiency.

Innovation Solution

A control method for dryers that adjusts the electric power and driving velocity of an inverter compressor based on determined driving conditions, such as the quantity of drying objects and peripheral temperature, to enhance the supply of heated air during the initial period.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a fixed velocity compressor is used in the heat pump, then the structure is simple, but the compression efficiency is compromised during the initial driving period

Engineering Contradiction:
Improvecompressor structureVSAvoidcompression efficiency
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies an inverter compressor that can dynamically adjust its rotation speed based on operating conditions. The control unit varies the compressor's rotation number according to the heat pump's operating state, enabling optimal compression efficiency during the initial driving period while maintaining simple overall system structure.

Inventive Principle:
Principle #15Dynamics

2Speed

If the compressor operates at maximum frequency from the start, then heated air is supplied quickly, but energy consumption increases

Engineering Contradiction:
Improveheated air supply speedVSAvoidcompressor energy consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The patent implements a multi-stage compressor operation strategy. During the initial driving period, the compressor operates at a first rotation number to quickly supply heated air. After this initial period, it transitions to a second rotation number for normal operation, and can adjust to a third rotation number based on drum temperature conditions, optimizing energy consumption throughout the drying cycle.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The control unit dynamically changes the compressor's rotation number parameter based on operating conditions, drum temperature, and time elapsed. This parameter adjustment strategy allows the system to achieve quick heated air supply when needed while reducing energy consumption during steady-state operation.

Inventive Principle:
Principle #35Parameter changes

3Use of energy by moving object

If the compressor rotation number is reduced below target maximum frequency, then energy consumption decreases, but heated air supply is delayed

Engineering Contradiction:
Improvecompressor energy consumptionVSAvoidheated air supply time
Core Design Contradiction:
Use of energy by moving objectVSLoss of time

Solution Approach 1:

The patent applies preliminary high-speed operation of the compressor during the initial driving period to quickly establish the heated air supply. This preliminary action ensures that the drying process starts efficiently, after which the compressor rotation number is adjusted to optimize energy consumption for the remainder of the cycle.

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 approach allows for quicker and more efficient heating in the initial driving period, reducing drying time and improving overall drying efficiency by optimizing the operation of the inverter compressor.

Implementation Method 1

a heat pump having an inverter compressor

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

heat pump generating heated air

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP2565322B1Control method of dryer
Publication Date: 2020.01.22 LG ELECTRONICS INC
  • EP2565322B1 patent drawingFigure 1
  • EP2565322B1 patent drawingFigure 2
  • EP2565322B1 patent drawingFigure 3

AI summary

The present invention relates to a control method of a dryer, and particularly, to a control method of a dryer having a heat pump equipped with a variable compressor, wherein the method comprises the steps of: checking the operating conditions of the dryer; and controlling at least one of electrical power supplied to the variable compressor and the operating speed of the compressor, according to the operating conditions.