Drain Motor Speed Control for Quieter Laundry Dewatering
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Solution Overview
Problem
Existing laundry treatment machines face challenges in efficiently driving drain motors during dewatering, leading to extended drainage times, increased pressure in the vortex chamber, noise, and vibration, and instability in converter operation.
Innovation Solution
A laundry treatment machine equipped with an inverter to convert DC voltage to AC voltage and a controller that manages the drain motor to operate at multiple speeds based on the washing tub motor's acceleration, including stopping or repeatedly turning on/off, to synchronize drainage with the washing tub's operation, thereby reducing pressure and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drain motor operates at high speed continuously during dewatering, then drainage efficiency is improved, but pressure in the vortex chamber increases causing noise and vibration
Solution Approach 1:
The drain motor is controlled to operate in intermittent cycles during dewatering: running at high speed for a predetermined time to achieve efficient drainage, then stopping to reduce pressure in the vortex chamber and eliminate noise/vibration. This periodic operation pattern resolves the contradiction between maintaining high drainage efficiency and preventing harmful noise and vibration.
Solution Approach 2:
The drain motor speed is dynamically adjusted based on operational requirements rather than maintaining a constant high speed. The controller switches between high-speed operation for drainage efficiency and zero-speed operation to reduce vortex chamber pressure, creating a dynamic control system that adapts to prevent noise and vibration while maintaining productivity.
2Stress or pressure
If the drain motor operates at variable speeds with repeated on/off cycles, then pressure in vortex chamber is reduced, but control complexity increases
Solution Approach 1:
The control system automatically manages the drain motor's on/off cycles and speed variations based on predetermined control logic. The controller monitors operational conditions and self-regulates the motor operation without requiring complex external intervention, reducing perceived control complexity while achieving pressure reduction through intelligent automated control.
Solution Approach 2:
The control system incorporates feedback mechanisms to monitor the drain motor operation and vortex chamber conditions. Based on this feedback, the controller adjusts the motor speed and on/off timing to maintain optimal pressure levels, managing the complexity through intelligent closed-loop control rather than simple open-loop switching.
3Adaptability or versatility
If the drain motor is controlled to match washing tub motor acceleration, then drainage is synchronized with washing cycles, but converter stability challenges arise
Solution Approach 1:
The drain motor operation is preliminarily coordinated with the washing tub motor acceleration phases. The controller anticipates the washing cycle requirements and pre-synchronizes drain motor startup and speed changes with the main motor's acceleration profile, ensuring smooth integration while managing converter load transitions to maintain stability.
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 solution enables efficient drainage, reduces noise and vibration, stabilizes the converter, and shortens the drainage completion period by synchronizing the drain motor's operation with the washing tub motor's acceleration and water level changes.
Implementation Method 1
an inverter to convert the DC voltage from the converter into an alternating current (AC) voltage based on a switching operation
Implementation Method 2
a controller to control the drain motor to operate at any one of a first speed, a second speed less than the first speed, and a stop when the washing tub motor is accelerated
Data Source
AI summary
The present disclosure relates to a laundry treatment machine. A laundry treatment machine according to an embodiment of the present disclosure including an inverter to convert the DC voltage from the converter into an alternating current (AC) voltage based on a switching operation and to output the converted AC voltage to the drain motor; and a controller to control the drain motor to operate at any one of a first speed, a second speed less than the first speed, and a stop when the washing tub motor is accelerated. Accordingly, according to the operation of the washing tub motor, it is possible to efficiently drive the drain motor.