Control method for a washing household appliance, and washing household appliance
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Solution Overview
Problem
Current washing household appliances' drainage pump units operate inefficiently and are prone to premature failure due to fixed frequency operation, leading to increased maintenance costs and reduced reliability, as they do not adapt to optimize drainage processes based on varying water levels or system conditions.
Innovation Solution
A control method that adjusts the frequency of the motor supply voltage for the drainage pump unit based on stator voltage characteristics, using field-oriented control to maintain optimal current consumption and operation within predetermined limits, ensuring efficient and reliable drainage processes across different motor constructions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the drainage pump unit operates at a fixed determined frequency for a determined period of time, then the drainage process is simple to control, but the reliability of the drainage pump unit deteriorates due to premature faults
Solution Approach 1:
The patent applies dynamics by transitioning from fixed frequency operation to variable frequency operation. The control means adjust the supply frequency of the synchronous motor dynamically based on detected water levels, allowing the drainage pump unit to adapt its operating parameters to actual drainage needs, thereby reducing unnecessary operation time and improving reliability
Solution Approach 2:
The patent implements feedback control by using level sensors to detect water levels and feeding this information back to the control means. The control means then adjust the motor supply frequency accordingly, creating a closed-loop system that optimizes pump operation based on real-time conditions, reducing operation time while maintaining drainage effectiveness
2Reliability
If the drainage pump unit is made bigger to overcome premature faults, then the reliability improves, but the cost increases excessively
Solution Approach 1:
The patent changes the operating parameters of the drainage pump unit by varying the supply frequency to the synchronous motor. Instead of increasing the physical size of the pump unit, the system adjusts electrical parameters (frequency and duration of operation) to optimize performance and reliability, avoiding the need for more expensive larger components
3Ease of operation
If the drainage pump unit operates for a determined period of time regardless of water level, then the control process is simple, but the efficiency deteriorates due to unnecessary operation
Solution Approach 1:
The control system uses level sensors to provide feedback on water levels during the drainage process. Based on this feedback, the control means dynamically adjust the operation duration and frequency of the drainage pump unit, stopping or reducing operation when water levels indicate drainage is complete or nearing completion, thereby eliminating unnecessary operation and improving efficiency
Solution Approach 2:
The patent implements periodic monitoring of water levels during the drainage process. The control means periodically adjust the pump operation based on detected water levels, creating an optimized periodic operation pattern that maintains efficiency without requiring complex continuous control
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 method enhances the reliability and efficiency of the drainage pump unit by optimizing current consumption and operating conditions, reducing the risk of premature failure and maintaining efficient drainage processes, while accommodating variations in motor construction characteristics.
Implementation Method 1
a permanent-magnet synchronous motor for rotating the impeller at a determined speed of rotation, by means of which drainage is caused... The synchronous motors are connected to the mains supply, which comprises a determined mains frequency, the speed of rotation of the impeller depending on said mains frequency
Implementation Method 2
a drainage pump unit with a variable frequency is used, which comprises an impeller and a BLDC-type motor for rotating said impeller... the frequency of the motor supply voltage is modified in order to vary the drainage water flow
Data Source
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AI summary
Control method for a washing household appliance comprising a drainage pump unit (1) with an impeller and a motor supplied with an alternating supply voltage of a determined frequency (F) from among a plurality of possible preset frequencies (F), the method comprising an adjustment stage (Ea) in which the frequency (F) of the motor supply voltage is regulated between the preset frequencies (F). The method also comprises an application stage (Em) in which a stator voltage (Vs) is applied to the motor, the frequency (F) of the motor supply voltage being regulated between the preset frequencies (F) in accordance with the stator voltage (Vs) applied.