Washing machine and method of controlling the same

Patent metadata

Field	Value
Publication number	US-10837134-B2
Application number	US-201715715517-A
Country	US
Kind code	B2
Filing date	Sep 26, 2017
Priority date	Sep 27, 2016
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

A washing machine and a method of controlling the same are disclosed. The amount of laundry that is introduced into the washing machine is measured using gravity and inertia applied during the operation of a motor, 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 that is operated is used to measure the amount of laundry without a sensor. Furthermore, precision in determining the amount of laundry is improved, and the amount of laundry is determined within a short time. Consequently, it is easy to commence the spin-drying operation, thereby reducing washing time and saving energy.

First claim

What is claimed is:

1. A washing machine comprising:
a motor to rotate a drum;
a power supply to provide operating power to the motor to selectively operate the motor and to control a rotational speed of the motor;
a current sensor to measure current of the motor during operation; and
a controller to transmit a control command for controlling the motor to the power supply, and to determine an amount of laundry contained in the drum based on current measured by the current sensor,
wherein:
the power supply provides the operating power to the motor such that the rotational speed of the motor is repeatedly maintained, increased, and decreased within a range between a first speed and a second speed in response to the control command,
the motor accelerates until the rotational speed changes to the first speed, maintains the rotational speed at the first speed for a particular amount of time, accelerates until the rotational speed of the motor changes from the first speed to the second speed, and decelerates from the second speed back to the first speed, and
the controller determines the amount of laundry contained in the drum based on respective currents measured by the current sensor during a maintenance period in which the rotational speed of the motor is maintained, an acceleration period in which the rotational speed of the motor increases, and a deceleration period in which the rotational speed of the motor decreases, and

wherein, when determining the amount of laundry in the drum, the controller is further configured to:
determine an initial estimate of the amount of laundry in the drum based on currents measured while the motor operates in a first rotational direction,
when the initial estimate of the amount of laundry is less than a threshold, determine that the amount of laundry corresponds to the initial estimate, and
when the initial estimate of the amount of laundry is not less than the threshold, direct the motor to operate in a second rotational direction, and determine the amount of laundry based on the initial estimate and further based on currents measured while the motor operates in the second rotational direction.

2. The washing machine according to claim 1 , wherein the power supply provides the operating power such that the motor is repeatedly accelerated and decelerated a particular number of times within the range between the first speed and the second speed.

3. The washing machine according to claim 1 , wherein the power supply provides the operating power such that after the motor is decelerated from the second speed to the first speed:
the motor maintains the rotational speed at the first speed for an amount of time, and
the motor accelerates until the rotational speed of the motor changes from the first speed to the second speed.

4. The washing machine according to claim 1 , wherein the controller sets a rotational speed of the motor in which the laundry tumbles in the drum as the first speed, and sets another rotational speed of the motor in which the laundry starts to cling to a wall of the drum by centrifugal force generated in the drum, a portion of the laundry rotates along with the drum when clinging to the wall of the drum, and another portion of the laundry is lifted up and dropped by the rotation of the drum as the second speed.

5. The washing machine according to claim 1 , wherein the controller determines the amount of laundry based on a gravitational force applied to the laundry in the maintenance period, inertia of the laundry in the acceleration period and the deceleration period, and counter-electromotive force applied in the deceleration period.

6. The washing machine according to claim 5 , wherein the controller excludes data in the maintenance period, in which the rotational speed of the motor is maintained, from data in the acceleration period and the deceleration period, in which the rotational speed of the motor is changed, to extract data on the inertia in the acceleration period and the deceleration period.

7. The washing machine according to claim 5 , wherein the controller subtracts current detected in the maintenance period from currents detected in the acceleration period and the deceleration period to form a first value, multiplies the first value by the counter-electromotive force to form a second value, and divides the second value by a variation of speed per unit time to extract data on the inertia of the laundry.

8. The washing machine according to claim 1 , wherein the controller multiplies currents detected in the maintenance period, the acceleration period, and the deceleration period by a counter-electromotive force calculated in the deceleration period to calculate laundry-amount sensing values for determining the amount of laundry.

9. The washing machine according to claim 8 , wherein the controller calculates the laundry-amount sensing values from averages of the currents detected in the maintenance period, the acceleration period, and the deceleration period.

10. The washing machine according to claim 8 , wherein
the controller determines the amount of laundry based on the laundry-amount sensing values in the acceleration period, the deceleration period, and the maintenance period using different data, and
the controller compares the laundry-amount sensing values in the acceleration period and the deceleration period with the laundry-amount sensing value in the maintenance period to determine the amount of laundry.

11. The washing machine according to claim 1 , wherein the rotational speed of the motor is varied in a repeated process in which the rotational speed is sequentially accelerated from the first speed to the second speed, and then decreased from the second speed to the first speed.

12. The washing machine according to claim 1 , wherein the repeated process includes sequentially repeating the acceleration from the first speed to the second and the deceleration from the second speed to the first speed a particular number of times.

13. The washing machine according to claim 12 , wherein the drum rotates in the first rotational direction during the repeated process, and another repeated process is performed in which in which the rotational speed is sequentially accelerated from the first speed to the second speed, and then decreased from the second speed to the first speed while the drum rotates in the second rotational direction that is opposite to the first rotational direction.

14. The washing machine according to claim 1 , wherein the drum receives laundry via an opening on a front surface of the washing machine.

15. The washing machine according to claim 1 , wherein the controller is further configured to manage a rotational speed of the drum during a spin-drying operation based on the amount of laundry contained in the drum.

16. The washing machine according to claim 15 , wherein the controller is further configured to determine a maximum rotational speed of the drum during the spin-drying operation based on the amount of laundry contained in the drum.

17. The washing machine according to claim 1 , wherein the controller is further configured to determine a limit value for unbalance during a spin-drying operation based on the amount of laundry contained in the drum.

18. The washing machine according to claim 1 , wherein the motor accelerates by a first rate during a first portion of the acceleration period and accelerates by a second rate during a second portion of the acceleration period, the first rate being smaller than the second rate.

Assignees

• Lg Electronics Inc

Inventors

• Lee Hoonbong
• Jang Minho
• Bae Jaegwang

Classifications

• D06F37/38

  in opposite directions · CPC title

• D06F2105/48

  Drum speed · CPC title

• D06F2103/46

  of the motor driving the drum · CPC title

• D06F2103/24

  Spin speed; Drum movements · CPC title

• D06F2103/04

  Quantity, e.g. weight or variation of weight · CPC title