Motor Preheating Current Control for Compressor Power Reduction

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Solution Overview

Problem

Existing motor driving apparatuses for compressors in home appliances consume excessive power during preheating due to constant current application regardless of compressor temperature, leading to inefficiencies and increased energy costs.

Innovation Solution

A motor driving apparatus with a temperature sensing unit and inverter controller that adjusts the duration and level of preheating current based on sensed refrigerant discharge temperature, reducing power consumption by increasing current application time or level as temperature decreases and decreasing it as temperature increases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If constant current is applied to the motor during preheating regardless of compressor temperature, then the compressor is adequately preheated, but power consumption increases excessively

Engineering Contradiction:
Improvecompressor temperatureVSAvoidpower consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamics by making the preheating current variable rather than constant. The controller dynamically adjusts the magnitude of preheating current based on real-time compressor temperature feedback, increasing current when temperature is low and decreasing it when temperature rises, thereby optimizing energy consumption while ensuring adequate preheating

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback control by using a temperature sensor to continuously monitor compressor temperature and feed this information back to the controller. The controller then adjusts the preheating current magnitude based on this feedback, creating a closed-loop control system that prevents excessive power consumption while maintaining effective preheating

Inventive Principle:
Principle #23Feedback

2Device complexity

If preheating is performed without temperature sensing, then the system structure is simpler, but power consumption cannot be optimized

Engineering Contradiction:
Improvesystem structureVSAvoidpower consumption
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The patent applies self-service by enabling the motor's own coil to serve dual purposes: both as the actuator for motor operation and as the heating element for compressor preheating. The controller intelligently controls the current through the coil to provide preheating functionality without requiring separate heating components, thus avoiding increased device complexity while enabling power consumption optimization through temperature-based control

Inventive Principle:
Principle #25Self-service

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 reduces power consumption during compressor preheating by optimizing current usage according to temperature conditions, enhancing energy efficiency without the need for additional heating components.

Implementation Method 1

a temperature sensing unit to sense a temperature around a compressor

Methodology Applied
Scientific EffectTemperature sensing:

Implementation Method 2

apply motor preheating current for preheating of the motor during a first period before startup of the motor

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3136591B1Motor driving apparatus and home appliance including the same
Publication Date: 2020.08.26 LG ELECTRONICS INC
  • EP3136591B1 patent drawingFigure 1~2A
  • EP3136591B1 patent drawingFigure 2B
  • EP3136591B1 patent drawingFigure 3

AI summary

Disclosed are a motor driving apparatus (220) and a home appliance (100) including the same. The motor driving apparatus (220) includes a temperature sensing unit (107) to sense a temperature around a compressor (102), an inverter (420) including a plurality of switching elements (Sa, Sb, Sc; S'a, S'b, S'c) and to convert a direct current (DC) voltage into an alternating current (AC) voltage by switching operation of the switching elements (Sa, Sb, Sc; S'a, S'b, S'c) and to supply the AC voltage to a motor (230) used to drive the compressor (102), and a controller (430) to control the inverter (420), and the controller (430) performs control to apply motor preheating current for preheating of the motor (230) during a first period before startup of the motor (230), and varies a time during which the motor preheating current is applied or a current application level depending on the sensed temperature. Thereby, a reduction in power consumption during the preheating of the compressor (102) is achieved.