Washing machine and method of controlling the same
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Solution Overview
Problem
Conventional washing machines face challenges in precisely determining the amount of laundry, especially with sensorless motors, leading to inefficiencies in spin-drying operations, increased washing time, and energy consumption.
Innovation Solution
A washing machine with a controller that measures the amount of laundry by analyzing current values during motor operation, utilizing inertial and gravitational forces, and adjusting rotational speed to accurately determine laundry quantity, even with sensorless motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the amount of laundry is determined at the time of starting the motor, then the measurement process is simple, but the measurement precision deteriorates due to initial position variations and laundry movement
Solution Approach 1:
The patent applies preliminary action by rotating the motor at a low speed before measurement to position the laundry uniformly around the drum perimeter. This preliminary rotation ensures that the laundry is evenly distributed and stable before the actual measurement begins, eliminating the effects of initial position variations and preventing laundry movement during measurement, thereby improving measurement precision without significantly increasing system complexity
2Productivity
If the motor is rotated at high speed for spin-drying with large amount of laundry, then the spin-drying capability is improved, but the reliability deteriorates due to unbalance and potential damage
Solution Approach 1:
The patent applies dynamics by implementing variable speed control of the motor based on the measured laundry amount. When a large amount of laundry is detected, the motor operates at a reduced speed during spin-drying to prevent unbalance and potential damage. When a small amount of laundry is detected, the motor operates at normal high speed to maintain spin-drying capability. This dynamic speed adjustment resolves the contradiction between productivity and reliability by adapting the operating conditions to the actual load
3Device complexity
If the washing machine includes a sensorless motor, then the device complexity is reduced, but the measurement precision deteriorates due to difficulty in positional alignment
Solution Approach 1:
The patent applies preliminary action by implementing a preliminary rotation phase before measurement when using a sensorless motor. During this phase, the motor rotates at a low speed to allow the laundry to distribute uniformly around the drum perimeter. This preliminary action compensates for the lack of positional alignment capability in sensorless motors, ensuring that the laundry is properly positioned and stable before measurement begins, thereby achieving acceptable measurement precision without requiring complex sensorless motor 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
This method allows for precise measurement of laundry quantity, reducing washing time and energy consumption by optimizing spin-drying operations based on the determined amount.
Implementation Method 1
determines the amount of laundry based on a current value in a low-speed maintenance period, a current value in an acceleration period, and a current value in a deceleration period
Implementation Method 2
utilizing inertial and gravitational forces, and adjusting rotational speed to accurately determine laundry quantity
Data Source
Figure 1
Figure 2
Figure 3~4(d)
AI summary
A washing machine and a method of controlling the same, wherein the amount of laundry that is introduced into the washing machine is measured using gravity and inertia applied during the operation of a motor (141) and, whereby it is possible to precisely calculate the amount of laundry and to minimize the effects of the initial position of the laundry and the movement of the laundry; in addition, a current value of the motor (141) that is operated is used to measure the amount of laundry without a dedicated sensor.