KR100301471B1 - Method of detecting the weight of laundary in washing machine - Google Patents

Abstract

PURPOSE: A clothing amount sensing method for a washing machine is provided to set a water level proper for a clothing amount by determining the clothing amount by detailed segmentation, thereby reducing the washing time and preventing the damage of clothing. CONSTITUTION: A clothing amount sensing method for a washing machine includes the steps of outputting a predetermined PWM(Pulse Width Modulation) duty according to a motor control logic while varying the PWM duty, determining whether a current rpm of a motor becomes equal to a target rpm after driving the motor according to the output PWM duty, repeating the first and second steps until the current rpm reaches the target rpm after adding a current PWM duty to a previous PWM duty, and determining a clothing amount according to a size of a total of the PWM duties used for raising the current rpm to the target rpm.

Description

Washing machine quantity detection method {METHOD OF DETECTING THE WEIGHT OF LAUNDARY IN WASHING MACHINE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a washing machine dose detection method. In particular, in a washing machine detection method using a brushless direct current (hereinafter referred to as "BLDC") motor, a BLDC motor is selected for initial detection. Pulse Width Modulation (hereinafter referred to as "PWM") used to raise the RPM (hereinafter referred to as "RPM") or Torque, using the sum of the control input values (with load and proportional characteristics) It relates to a washing machine quantity detection method for detecting the quantity.

1 is a longitudinal cross-sectional view schematically showing a configuration of a conventional washing machine, as shown in the BLDC motor 2 is fixed to the lower side of the washing machine case 1, the lower portion of the central axis of the case (1) the BLDC The clutch 3 connected through the motor 2 and the belt 11 is mounted, and a washing tank (outer tank, 4) and a dehydration tank (inner tank, 5) are provided in two layers on the central axis of the clutch 3, and the dewatering A pulsator 6 is coupled to the inner bottom of the tub 5 on the central axis, and a damper 7 supporting the wash tub 4 from all sides is symmetrical on the outer circumferential surface of the lower end of the tub 4. Each damper 7 has a structure in which a snubber bar 8 that absorbs vibration by friction is coupled thereto. Here, reference numeral 9 denotes a water supply valve, and 10 denotes a water level sensor.

Referring to the operation of the conventional device configured as described above are as follows.

In the washing machine, the detection of the quantity can be done in various ways.However, in the washing machine adopting the induction motor, a method based on the counter electromotive force of the motor is widely used in the degree of detection and the price. Same as

When the laundry is put into the washing tank 4, and the power source 14 is supplied through the triac 13 to drive the motor 2 as shown in FIG. 2, the rotational force of the motor 2 passes through the belt 11, and then the clutch 11. It is transmitted to the pulsator 6 through 3 and rotates. When the power applied to the motor 2 is turned off, the pulsator 6 is rotated by the rotational inertia. This rotation causes the motor 2 to be connected to the clutch 3 and the belt 11. Rotate () backwards. At this time, due to the current flowing in the power supply 14 to the motor 2, a certain amount of current remains in the rotor even after the power is turned off, and gradually decreases. Due to this current and rotation of the force of the motor 2, the voltage is induced in the windings of the stator in the attenuation waveforms as shown in Fig. 3A at the nodes 1 and 2. This induced voltage appears in the form of a pulse through the photo coupler 12 as shown in FIG. 3B. The number of pulses appearing at this time has a correlation with the amount of laundry in the washing tub 4. In other words, if the amount of the laundry is large, the weight and volume is large, and stops immediately by the friction with the washing tank 4, if the laundry is small, the friction surface with the washing tank 4 is smaller, the rotation is relatively much.

In particular, in a washing machine using a BLDC motor having a Hall-sensor (not shown), as shown in FIG. 4, a method of detecting a quantity of dose using a time taken to raise the quantity of detection to a predetermined amount of detection RPM is provided. Used.

As described above, in the prior art, by determining the quantity of storage according to the rising time of the BLDC motor, it is affected by voltage fluctuations and the like, and the quantity detection error becomes large, and according to the detection error of the quantity of water supplied There was a problem that the water level is set incorrectly resulting in damage to the laundry.

Accordingly, the present invention has been made to solve the above-mentioned conventional problems, and is a pulse width modulation (PWM) duty used to raise the BLDC motor to a predetermined RPM or torque for initial capacity detection. It is an object of the present invention to provide a method for detecting a quantity of fire by using a sum of control input values (having a load and a proportional characteristic).

1 is a longitudinal sectional view schematically showing a configuration of a conventional washing machine.

Figure 2 is a schematic diagram showing a brief configuration of the counter electromotive force detection of the conventional washing machine.

3 is an output waveform diagram of nodes 1 and 2 according to counter electromotive force in FIG. 2.

Figure 4 is a graph showing the relationship between the conventional dose detection ALPM and the arrival time.

5 is a control flowchart of the present invention.

6 is a graph showing the relationship between the total sum of the dose amount and the pulse width modulation value applied to the present invention.

*** Description of the symbols for the main parts of the drawings ***

1: washing machine case 2: motor

3: clutch 4: washing tank (outer tank)

5: dehydration tank (inner tank) 6: pulsator

7: damper 8: snubber bar

11: belt 12: photocoupler

13: triac 14: power

Washing machine quantity detection method of the present invention for achieving the above object comprises the first step of outputting while changing the predetermined pulse width modulation value (PWM duty) according to the motor control logic when the laundry is newly input; A second step of driving the motor according to the pulse width modulation value output in the first step and then determining whether the current RPM has reached the target RPM; A third step of repeating the first and second steps until the target RPM is reached after adding the current pulse width modulation value to the previous pulse width modulation value if the determination result of the second step is not reached; When the determination result of the second step is reached, it comprises a fourth step of determining the dose according to the magnitude of the total sum of the pulse width modulation value used to raise to the target ALPM.

Hereinafter, an embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 5 is a control flow chart of the present invention. As shown in FIG. 5, when a consumer puts laundry into the washing tank 4 of FIG. 1 and operates, a predetermined pulse width modulation value (PWM duty) is determined according to the motor control logic. Outputs while varying at each sampling time, and as the pulse width modulation value increases, RPM, which is the rotational speed of the motor 2, increases in proportion thereto. Thereafter, it is determined whether the current RPM has reached the target RPMr at the predetermined sampling time (RPMr ≦ RPM). If the determination result is not reached, the current pulse width modulation value PWM and the previous pulse width modulation value are not reached. After summing (PWMt), the operation is repeated until the target RPMr is reached, and when the determination result reaches the target RPMr, the total pulse width modulation value used to raise the target RPMr to the target RPMr is calculated. The quantity is determined according to the magnitude of the sum RPMT. In this case, as the amount of load increases, the load on the motor 2 increases in proportion to the amount of load, so that the total sum value RPMT of the pulse width modulation value also increases, so that the quantity can be determined from the total sum value RPMT. Will be. That is, as shown in FIG. 6, the total sum value (RPMT) of the pulse width modulation value and the load amount have a proportional relationship, and as the total sum value (RPMT) of the pulse width modulation value is larger, it is determined that the load amount is large. Determine.

When the amount is determined as described above, the driving of the motor 2 is stopped, the amount of detergent is displayed, and when the amount of detergent is completed, the washing operation is started according to the determined amount.

As described above, the washing machine quantity detection method of the present invention can further subdivide the amount of laundry, so that an appropriate level can be set according to the subdivided quantity, thereby saving the amount of water and electricity, and Judgment has the effect of saving the washing time and reducing the environmental pollution by the use of a suitable detergent.

Claims (1)

A first step of outputting the laundry while the new laundry is added while varying a predetermined pulse width modulation value (PWM duty) according to the motor control logic; A second step of driving the motor according to the pulse width modulation value output in the first step and then determining whether the current RMP has reached the target RPM; A third step of repeating the first and second steps until the target RPM is reached after adding the current pulse width modulation value to the previous pulse width modulation value if the determination result of the second step is not reached; And a fourth step of determining, based on the magnitude of the total sum of the pulse width modulation values used to raise the target ALPM when the determination result of the second step is reached.