Laundry Drum Load Monitoring via Motor Current and Drying Energy
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Solution Overview
Problem
Current tumble dryers lack precise monitoring capabilities for the load on the laundry drum and the degree of dryness of laundry items, making it difficult to predict the remaining drying time accurately.
Innovation Solution
A method and circuit arrangement that utilize an electric motor with a stator winding, where the motor current is measured to infer the load and degree of dryness, allowing for precise monitoring and control of the drying process by regulating the motor speed and power consumption based on current values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current monitoring methods are used in tumble dryers, then the device complexity is reduced, but the measurement precision of load and degree of dryness is insufficient
Solution Approach 1:
The system uses the motor's own current consumption as the measurement parameter for monitoring load and degree of dryness. The control device measures the current already flowing through the motor windings during normal operation, eliminating the need for separate measurement systems. This self-service approach provides precise measurements while maintaining simple device architecture.
Solution Approach 2:
The motor current serves multiple functions: it drives the laundry drum and simultaneously provides information about load and drying progress. By utilizing the existing motor current for monitoring purposes, the system achieves multi-functionality without adding separate monitoring hardware, thus improving measurement precision while keeping device complexity low.
2Productivity
If the laundry drum is rotated at high speed throughout the entire drying process, then the drying efficiency is improved, but the power consumption increases
Solution Approach 1:
The motor speed is dynamically adjusted during the drying process based on real-time current measurements. The control device modifies the rotation speed according to the detected load and drying progress, allowing the system to operate at high speed when needed and reduce speed when load decreases, thereby optimizing both drying efficiency and power consumption.
Solution Approach 2:
The system performs periodic measurements of motor current during the drying process and adjusts speed accordingly. This periodic monitoring and adjustment enables the system to maintain optimal drying efficiency while reducing power consumption by adapting speed to changing load conditions throughout the drying cycle.
3Measurement precision
If the motor speed is continuously adjusted to optimize drying, then the measurement precision of drying progress is improved, but the device complexity increases
Solution Approach 1:
The control device continuously measures the motor current and uses this feedback information to determine drying progress and adjust motor speed. This feedback mechanism provides precise monitoring of drying progress while using a simple control approach that analyzes existing current data, avoiding the need for complex additional sensing and control systems.
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
Enables accurate prediction and regulation of the remaining drying time, detects changes in load and dryness, and minimizes power consumption, with the ability to signal overloading and determine when laundry is dry.
Implementation Method 1
The laundry drum is driven by an electric motor, which has a stator with at least one electrical winding
Data Source
Figure 1~2
Figure 3
AI summary
The method involves controlling an electric motor i.e. permanent magnet excited synchronous motor, using a control device by applying electric voltage at a winding of a stator of the motor. Electric current flowing across the winding is measured by the control device. Energy (delta E) supplied to the electric motor is estimated based on the measured current. Drying level of laundry and/or loading of a drum is inferred based on distribution of energy over time. The drum is driven by the electric motor. An independent claim is also included for a circuit arrangement for monitoring loading of a drum and/or drying level of laundry in the drum.