Drain Pump Frequency Control for Washer Current Optimization
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Solution Overview
Problem
Existing washing household appliances face reliability and efficiency issues with drainage pump units due to fixed frequency operation, leading to premature faults and increased manufacturing costs, as they do not optimize drainage processes based on varying water levels or flow requirements.
Innovation Solution
A drainage pump unit with a BLDC motor supplied by a variable-frequency alternating voltage, controlled by means that monitor and adjust the motor current to maintain optimal consumption, ensuring a full-flow drainage process with minimal strain and efficient operation within predefined limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drainage pump unit operates at fixed frequency for preset time, then the drainage process can be completed, but the pump unit experiences premature faults due to excessive activation time and strain
Solution Approach 1:
The patent applies dynamics by transitioning from fixed-frequency operation to variable-frequency operation. The control means adjust the motor frequency dynamically during the drainage process based on monitored current levels, allowing the pump to operate more efficiently and reduce overall activation time while maintaining reliability.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the motor current and using this information to adjust the supply frequency. The control means compare the monitored current with stored reference values and modify the frequency accordingly, creating a closed-loop system that optimizes pump operation and reduces strain.
2Productivity
If the drainage pump unit operates at fixed frequency, then the control system is simple, but the drainage process efficiency is not optimized based on varying water levels or flow requirements
Solution Approach 1:
The patent applies parameter changes by modifying the supply frequency to the motor during operation. The control means adjust the frequency parameter based on monitored current and stored reference values, optimizing drainage efficiency without requiring complex mechanical modifications to the pump unit.
3Duration of action of moving object
If the pump unit dimensions are increased to decrease activation time, then the drainage capacity is improved, but the manufacturing costs increase and the appliance scalability is adversely affected
Solution Approach 1:
The patent changes the operational parameters (frequency and current) of the existing pump unit to achieve faster drainage times without modifying the physical dimensions of the pump. This approach avoids increased manufacturing costs and maintains appliance scalability.
4Productivity
If the pump unit operates at higher current to complete drainage faster, then the productivity is improved, but the strain on the pump unit increases leading to premature faults
Solution Approach 1:
The patent uses feedback control to monitor motor current continuously and adjust frequency accordingly. By comparing monitored current with stored reference values, the system optimizes the balance between drainage speed and pump strain, preventing premature faults while maintaining productivity.
Solution Approach 2:
The system dynamically adjusts operating conditions during drainage, transitioning from static high-current operation to dynamic current-frequency coordination. This reduces peak strain on the pump while maintaining effective drainage throughput.
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
The solution provides improved reliability and efficiency by optimizing the drainage process, reducing strain on the pump unit and ensuring correct operation with minimal current consumption, thus extending the unit's lifespan and reducing manufacturing costs.
Implementation Method 1
a drainage pump unit with an impeller and a BLDC type motor to allow the rotation of the impeller
Implementation Method 2
The consumption current of the motor is determined, and the current is linked to a water level
Implementation Method 3
The frequency of the motor supply voltage is changed to vary the flow of drainage water in accordance with the associated water level
Data Source
AI summary
An appliance having a drain pump with a motor adapted to be supplied with an alternating supply voltage. A controller is adapted to monitor a current value supplied to the motor and to control the frequency of the supply voltage among a plurality of predetermined frequencies when the drain pump is operated in a full drainage mode. A storage medium associated with the controller stores for each predetermined frequency a maximum current value, a minimum current value and an optimal current value. The controller may stores computer implemented instructions for (a) determining if the monitored current value is between the maximum current value and the minimum current value, (b) comparing the monitored current value with the optimal current value, and (c) adjusting the frequency of the alternating supply voltage among the plurality of predetermined frequencies to cause the monitored current to more closely match the optimal current value.