Washer Drain Pump Control Using Current and Speed Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Laundry treatment machines face issues with pump overload and inefficient water drainage due to clogged drains and abnormal water flow, leading to continuous operation without complete drainage and potential damage.
Innovation Solution
A washing machine system that includes a pump, motor, motor driver, motor controller, current sensor, speed sensor, and water level sensor, which determines the load state of water and controls the motor's operation based on measured current and rotation speed to prevent overload and ensure complete drainage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pump continues operating after water is completely drained, then the pump may be damaged due to overload, but stopping the pump too early may leave water undrained
Solution Approach 1:
The system uses current sensors and speed sensors to continuously monitor the motor's operating parameters and provides feedback to the controller. When the current drops below a threshold or speed increases beyond a set value, the controller determines water is drained and stops the motor, preventing overload while ensuring complete drainage.
Solution Approach 2:
The pump system monitors its own operating state through current and speed sensors, automatically determining when water drainage is complete and stopping itself without external intervention. This self-service mechanism prevents both overload damage and incomplete drainage.
2Reliability
If the drain is clogged with foreign substances, then water drainage is blocked, but the pump continues operating causing overload and potential damage
Solution Approach 1:
The current sensor detects abnormal current increase when the drain is clogged, and the speed sensor detects reduced rotation speed. This feedback signals the controller to stop the motor, preventing overload damage while identifying the clogging condition.
Solution Approach 2:
The system monitors current and speed parameters before overload damage occurs. By detecting abnormal changes in advance, the controller can stop the motor preemptively, cushioning against potential damage from prolonged operation under clogged conditions.
3Measurement precision
If multiple sensors and control systems are added to monitor water drainage status, then accurate detection of drainage completion is achieved, but device complexity increases
Solution Approach 1:
The motor's own current and speed parameters are used as indicators of water drainage status. By leveraging the motor's inherent operational characteristics, the system achieves accurate water level detection without requiring separate water level sensors, thus maintaining measurement precision while reducing device complexity.
Solution Approach 2:
The current sensor and speed sensor serve dual purposes: monitoring motor performance and detecting water drainage status. This multi-functionality eliminates the need for dedicated water level sensors, achieving accurate measurement while simplifying the overall system.
Data Source
AI summary
A washing machine is disclosed. The washing machine includes a pump that is configured to drain or circulate water and that comprises a motor that is configured to operate the pump. The washing machine further includes a motor driver that is configured to supply operation power to the motor. The washing machine further includes a motor controller that is configured to set a rotation speed of the motor and that is configured to supply, to the motor driver, a signal that controls the motor. The washing machine further includes a current sensor that is configured to measure a current supplied from the motor driver to the motor. The washing machine further includes a speed sensor. The washing machine further includes a water level sensor. The washing machine further includes a main controller that is configured to start or stop operation of the motor by supplying a control command.