KR100296284B1 - Method of detecting the weight of saundary in washing machine - Google Patents

Abstract

PURPOSE: A clothing amount sensing method for a washing machine is provided to precisely sense a clothing amount with reserved energy after rotating at a constant speed. CONSTITUTION: A clothing amount sensing method for a washing machine includes the steps of controlling a PWM(Pulse Width Modulation) duty until a current rotation velocity of a motor becomes equal to a reference rotation velocity after driving the motor, controlling the PWM duty for maintaining the current rotation velocity of the motor constantly for a predetermined time period, measuring first and second time periods taken to reach a first and second deceleration rotation velocities by the surplus power of the motor after turning off the motor, and determining a clothing amount by computing a deceleration inclination from the first and second time periods.

Description

METHODS OF DETECTING THE WEIGHT OF SAUNDARY IN WASHING MACHINE

The present invention relates to a method for detecting a quantity of washing machine, and in particular, in detecting a quantity of laundry during washing of a direct drive type washing machine in which a motor and a washing machine are directly connected to each other, by rotating the washing machine at the same speed and stabilizing, It relates to a quantity detection method of the washing machine for detecting the quantity using the rotation.

For the convenience of the user, the washing process is performed by detecting the exact amount of washing in the automatic washing machine in which the whole process of washing is performed only with an operation button, thereby determining the washing level, washing time, detergent amount, rinsing and washing water flow.

Representative methods of the capacity detection method of the fully automatic washing machine include a method using a signal generated by the back electromotive force by using the power characteristics of the motor, and a method of detecting the quantity by measuring the motor rotation speed using a Hall sensor.

In general, in the conventional direct drive type washing machine, as illustrated in FIG. 1, the outer tub 11 in which the washing water is contained in the main body 10 is installed in a suspended state by a suspension device (not shown). 11, a washing tank 12 into which laundry is directly injected into the laundry is installed, and a pulsator 13 is integrally formed with the washing tank 12 in the center of the lower end of the washing tank 12, and the washing tank ( 12) a fluid balancer (not shown) is installed on the inner circumferential surface of the upper end to reduce vibration generated during dehydration.

In addition, the lower end side of the outer tub 11 is equipped with a brushless direct current (hereinafter referred to as "BLDC") motor 14 for generating power during washing and dehydration, the BLDC motor 14 The motor shaft 15 is installed in a state directly connected to the lower end of the washing tank 12 is configured.

Referring to Figure 2 attached to the operation of the conventional device configured as described above are as follows.

As a method for detecting a dose, as illustrated in FIG. 2, a dose is detected by mixing a characteristic of starting and a characteristic of starting of the BLDC motor 14, and FIG. 2A illustrates a reference pulse width modulation (PWM) duty value. After setting the value, the BLDC motor 14 is driven while changing the pulse width modulation duty value, and when the reference pulse width modulation value is reached, the motor speed at that time is measured, and a predetermined time after the BLDC motor 14 is turned off It measures the value of the rotational speed (RPM) at the next time.When the reference pulse width modulation duty value is reached according to the weight of the gun, the difference between the rotational speed (RPM) and the change in the rotational speed (RPM) change at 2B is a method of using the rotational speed (RPM) value at the time when the washing tank 12 takes a fixed time rotation after the motor starting time and when the reference pulse width modulation value is reached (at the normal section). There is this.

FIG. 3 is a block diagram illustrating a control device of the BLDC motor in FIG. 1, wherein a three-phase AC power supply 20 is shown; A rectifier 21 for rectifying the three-phase AC power source 20; A capacitor 22 for smoothing the output voltage of the rectifier 21; An inverter 23 for converting the DC voltage of the capacitor 22 into an AC voltage through pulse width modulation (PWM) duty control; An inverter controller (24) for controlling the pulse width modulation duty of the inverter (23); A BLDC motor 25 driven by an AC voltage output from the inverter 23; It is composed of a position sensor 26 for calculating the position and speed of the BLDC motor 25, Figure 4 is an equivalent circuit diagram of the inverter 23 and the BLDC motor 25 in Figure 3, the power switching as shown The characteristics of elements PS1 to PS6, DC link voltage, free wheeling diodes D1 to D6, and characteristics of the BLDC motor 25 can cause scattering and error in the quantity detection. have. In other words, if the acceleration section is used as a dose sensing element, it is difficult to detect a desired dose because it is sensitive to voltage fluctuations, device-specific dispersion, and temperature causes. If only the margin time is used to compensate for this, it is not easily affected by the disturbance (voltage fluctuation, etc.), but in the washing machine in which the washing tank rotates, the capacity characteristics of the washing tank may not be well represented.

As described above, in the conventional technology, a difference in the number of pulses occurs according to changes in ambient temperature, voltage fluctuations, position state of the cloth during washing, and the like. The variation of each set becomes large, and when the capacity is used, the capacity characteristics (weight characteristics of the clothes) are not easily displayed due to the inertia force of the washing tub, and the water level setting is incorrect due to the detection error of the quantity of the laundry. As a result, there was a problem of causing damage to laundry and deterioration of cleaning power.

Therefore, the present invention was devised to solve the conventional problems as described above, and after stabilizing by rotating the laundry at a constant speed at the same speed, the amount of sensing the damping slope of the rotational speed according to the rotation of the force when the motor off to detect the quantity The purpose is to provide a way to.

1 is a longitudinal sectional view schematically showing the configuration of a conventional direct drive type washing machine.

FIG. 2 is a graph showing a method for detecting a quantity used in FIG. 1. FIG.

3 is a block diagram showing a configuration of a control device of the BLDC motor in FIG.

4 is an equivalent circuit diagram of an inverter and a BLDC motor in FIG.

5 is a flow chart according to the quantity detection method of the present invention.

6 is a graph showing a method for detecting a quantity used in the present invention.

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

10: body 11: outer tank

12: washing tank 13: pulsator

14, 25: BLDC motor 15: motor shaft

20: 3-phase AC power supply 21: rectifier

22: capacitor 23: inverter

24: inverter control unit 26: position sensor

PS1 to PS6: Power switching element D1 to D6: Freewheeling diode

The quantity detection method of the washing machine of the present invention for achieving the above object comprises a first step of driving a motor when the laundry is put, and determining whether the current rotational speed of the motor is the same as the reference rotational speed; A second step of controlling a pulse width modulation duty (PWM Duty) and then repeatedly performing the first step if the determination result of the first step is not the same; A third step of determining whether to maintain a constant speed for a predetermined time when the determination result of the first step is the same; As a result of the determination in the third step, if the constant speed is not maintained, the flow returns to the second step; if the constant speed is maintained, the driving of the motor is turned off, and the arrival time at which the predetermined deceleration rotation speed is reached when the motor is free Performing a fourth step; After the execution of the fourth step is characterized in that it comprises a fifth step of determining the amount of the dose by calculating the attenuation slope from the arrival time and ends.

In the fourth step, in order to minimize data dispersion, measuring the first reaching time and the second reaching time respectively reaching the first deceleration rotation speed and the lower deceleration rotation speed, which are preset values when the motor is free, It further comprises.

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

FIG. 5 is an operation flowchart of the present invention, and when laundry is input as shown in FIG. 5, the BLDC motor 25 of FIG. 3 is driven, and the position sensor (6) is used to detect the rotation speed (RPM) of the BLDC motor 25. After calculating the speed using the signal of 26), the reference rotational speed (RPMd) and the current rotational speed (RPMc) are compared with each other (RPMd == RPMc), and based on the comparison result, the reference rotational speed (RPMd) If the current rotation speed (RPMc) is the same, the constant speed time (Ts) (hereinafter referred to as "constant speed") is calculated from the time when the reference rotation speed (RPMd) is entered, so that the constant acceleration time is the same for all the guns. After speed control, the drive of the BLDC motor 25 is turned off and then rotated by the power of the motor.

Thereafter, as shown in FIG. 6A, the time from the drive-off time of the BLDC motor 25 to the stoppage of the washing tank 12 of FIG. 1 is used in order to use an optimal slope section at the time of rotating the power. A method of using the sampled data using a timer, and turning off the drive of the BLDC motor 25 at the reference rotational speed (rpm) to minimize the data scatter as shown in FIG. 6B, and then the BLDC motor. In order to eliminate the error factor caused by the shaking of the washing tank 12 when the predetermined first deceleration rotation speed (rpm1) is stopped at the time due to the power of (25), that is, using the data sampled to the lower limit value (rpm2). After the arrival time T1 at which the first deceleration speed rpm was reached was measured, and the arrival time T2 at which the second deceleration rotation speed rpm was reached at the lower limit was measured, the arrival times T1 and T2 were measured. Calculate the damping slope from Decide

As described above, the quantity detection method of the washing machine according to the present invention stabilizes by rotating the washing tub at a constant speed at the same speed, and then determines the amount of laundry by determining the attenuation slope of the rotational speed according to the turning force of the motor when the motor is turned off. By setting the appropriate water level according to this subdivided quantity, it is possible to save energy such as water and electricity, and also to prevent damage and entanglement of the laundry, and to use detergent according to the appropriate washing quantity, It is effective in preventing environmental pollution.

Claims (1)

A first step of driving a motor when laundry is put in and controlling a pulse width modulation duty until a current rotation speed of the motor becomes equal to a reference rotation speed; A second step of controlling the pulse width modulation duty such that the current rotational speed of the motor maintains a constant speed for a predetermined time; A third step of turning off the driving of the motor and measuring first and second arrival times respectively reaching the first deceleration rotation speed and the second deceleration rotation speed of the lower limit, respectively, by the power of the motor; And a fourth step of determining a quantity by calculating an attenuation slope from the first and second arrival times measured in the third step.