Drain Pump Motor Speed Control for Quiet Washer Dewatering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Laundry treatment machines face challenges in reducing noise and vibration during dewatering due to varying lift levels, which affect the stability of the drain pump motor and drainage performance, and require sensor-based speed control to manage power output effectively.
Innovation Solution
A controller is implemented to adjust the motor speed based on output current and lift levels, allowing the motor to operate at different speeds and power levels, ensuring constant power supply and minimizing noise and vibration, while enabling sensorless operation and improved drainage efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor is driven at a constant speed using input AC power, then the motor operation is simple and stable, but noise and vibration occur due to residual water movement in the drain pipe when lift levels vary
Solution Approach 1:
The motor speed is changed from constant to variable based on lift level. The controller adjusts the motor speed dynamically: at low lift levels, the motor operates at a first speed, and at high lift levels, it operates at a second speed greater than the first speed. This dynamic speed adjustment prevents residual water movement and reduces noise and vibration while maintaining reliable motor operation.
2Object-generated harmful factors
If the motor speed is adjusted according to lift levels to reduce noise and vibration, then noise and vibration are reduced, but the converter stability is reduced due to wide range power level requirements
Solution Approach 1:
The motor speed is adjusted by changing operational parameters (speed levels) rather than requiring wide range power level adjustments. The controller is configured to operate the motor at specific discrete speed levels corresponding to different lift conditions, which maintains converter stability while still reducing noise and vibration through appropriate speed selection.
3Productivity
If the motor speed is increased to improve drainage performance, then drainage efficiency improves, but noise and vibration increase due to residual water movement
Solution Approach 1:
The motor operates at different speed parameters depending on lift level. At low lift levels where drainage performance may be insufficient, the motor runs at a higher first speed. At high lift levels where drainage performance is adequate, the motor runs at a lower second speed, reducing noise and vibration while maintaining acceptable drainage efficiency.
Data Source
AI summary
The present disclosure relates to a laundry treatment machine. According to an embodiment of the present disclosure, a laundry treatment machine includes a controller controlling a motor, during dewatering, to be driven at a first speed when a lift is at a first level and to drive the motor at a second speed greater than the first speed when the lift is at a second level greater than the first level, wherein the lift is a difference between a water level of a water introduction part through which water flows into a drain pump and a water level of a water discharge part through which the water is discharged out of the drain pump. Accordingly, noise or vibration can be reduced even if the lift is changed during the dewatering.