Washer Drain Pump Current Feedback for Low-Strain Drainage

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Solution Overview

Problem

Washing household appliances face premature faults in drainage pump units due to inefficient control methods that do not optimize drainage processes, leading to increased strain and difficulty in replacing components, often resulting in higher costs when addressing these issues.

Innovation Solution

A washing household appliance with a drainage pump unit using a BLDC motor supplied with alternating voltage at selected frequencies, where control means monitor and regulate the motor current to maintain optimal consumption, ensuring a full-flow drainage process with minimal strain by adjusting the frequency between preset limits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the drainage pump unit operates at a preset frequency for a preset time, then the drainage process can be completed, but the pump unit experiences increased strain and premature faults due to non-optimized operation

Engineering Contradiction:
Improvedrainage pump unit reliabilityVSAvoidpump unit operation time
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent applies dynamics by transitioning from fixed preset frequency operation to variable frequency operation. The control means adjust the motor frequency dynamically during the drainage process based on monitored parameters, allowing the pump to operate optimally at different stages rather than maintaining a constant speed throughout.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback by continuously monitoring the motor current and using this information to adjust the operating frequency. The control means compare the monitored current with stored reference values and modify the frequency accordingly, creating a closed-loop control system that optimizes pump operation in real-time.

Inventive Principle:
Principle #23Feedback

2Reliability

If the drainage pump unit is designed with more generous dimensions to handle variable loads, then reliability improves, but the cost and complexity of the appliance increases

Engineering Contradiction:
Improvedrainage pump unit reliabilityVSAvoidappliance complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by modifying the electrical parameters (frequency and current) of the motor operation rather than changing the physical dimensions of the pump components. The control means adjust frequency and monitor current to keep the pump operating within optimal parameters, extending reliability without requiring larger or more robust hardware.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the pump unit operates at higher frequencies to complete drainage faster, then productivity increases, but the motor current increases and reliability decreases

Engineering Contradiction:
Improvedrainage speedVSAvoidpump unit reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies periodic action by using different frequency levels at different stages of the drainage process. The control means monitor the water level and current, adjusting the frequency periodically rather than maintaining a constant high frequency, thus achieving effective drainage while preventing excessive strain on the motor.

Inventive Principle:
Principle #19Periodic 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 enhances the reliability and efficiency of the drainage pump unit by operating within optimal current consumption levels, reducing strain and extending the unit's lifespan while maintaining correct operation, achieved through simple and economical means.

Implementation Method 1

a drainage pump unit with an impeller and a motor supplied with an alternating supply voltage... a BLDC type motor to allow the rotation of said impeller

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2248935B1Washing household appliance and control method thereof
Publication Date: 2011.08.10 COPRECITEC
  • EP2248935B1 patent drawingFigure 1~2
  • EP2248935B1 patent drawingFigure 3~4
  • EP2248935B1 patent drawingFigure 5~6

AI summary

Washing household appliance (100) comprising a drainage pump unit (1) with an impeller and a motor supplied with an alternating supply voltage of a plurality of possible preset frequencies (F), and control means (3) to monitor a current of the motor and control said motor in accordance with said current, thereby regulating the frequency (F) of the motor supply voltage. The appliance also comprises storage means (4) that store, for each of the possible preset frequencies (F), an optimal current of the motor corresponding with a required current of the motor so that the pump unit operates under as little strain as possible. The control means compare the monitored current with the optimal current and regulate the frequency (F) so that the current is equal to or as close as possible to the optimal current, in accordance with the result of said comparison.