Laundry Dryer Fan Speed Control Based on Drum Motor Load Detection
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Solution Overview
Problem
Conventional laundry dryers often operate at maximum load settings, even when the actual load is lower, leading to inefficient drying cycles and reduced performance.
Innovation Solution
A method for controlling a laundry dryer with a variable speed fan motor and drum motor, where the speed of the fan motor is adjusted based on the power or current absorbed by the drum motor, increasing speed for partial loads to enhance air flow and reduce drying time, particularly in heat pump dryers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the fan motor operates at maximum speed for all loads, then the drying air flow rate is sufficient for maximum load, but the drying time is extended unnecessarily for partial loads
Solution Approach 1:
The fan motor speed is made dynamic and adjustable based on the detected load amount. The control unit modifies the fan motor operating points according to the actual laundry load, allowing the system to adapt its air flow rate to match the drying requirements of the current load size, thereby reducing unnecessary drying time for partial loads.
Solution Approach 2:
The operating parameters of the fan motor are changed based on load detection. By detecting the load amount and相应地 adjusting the fan motor speed and air flow rate, the system optimizes the drying process for different load sizes, improving productivity while minimizing cycle duration.
2Productivity
If the fan motor speed is increased for partial loads, then the drying efficiency is improved, but the energy consumption increases
Solution Approach 1:
The fan motor operating parameters are dynamically adjusted based on the detected load amount. For partial loads, the system optimizes the balance between drying efficiency and energy consumption by modifying the fan motor speed and air flow rate to match the actual drying requirements, avoiding unnecessary energy expenditure while maintaining effective drying performance.
3Reliability
If the drying air stream fan operates at fixed maximum capacity, then the air flow rate is sufficient for maximum load, but the heat exchange efficiency is reduced for partial loads
Solution Approach 1:
The drying air stream fan operates dynamically with adjustable speed and air flow rate based on load detection. The control unit modifies the fan motor operating points according to the actual laundry load, allowing the system to maintain optimal heat exchange efficiency for different load sizes while ensuring sufficient drying performance.
Data Source
AI summary
A method is provided for controlling a laundry dryer including a fan motor (26) for driving a drying air stream fan (18) with a variable speed (vf) and a drum motor (28) for driving a laundry drum (12). The method comprises the steps of setting a predetermined course for the speed (vd) of the drum motor (28), maintaining the speed (vd) of the drum motor (28) according to the predetermined course for the speed (vd) of said drum motor (28), detecting a power (Pd) or a current absorbed by the drum motor (28), and controlling the speed (vf) of the fan motor (26) on the basis of the absorbed power (Pd) or current of the drum motor (28). The speed (vf) of the fan motor (26) increases with a decreasing absorbed power (Pd) or current of the drum motor (28) and/or the speed (vf) of the fan motor (26) decreases with an increasing absorbed power (Pd) or current of the drum motor (28).