KR20060029860A - Motor control method of a washer - Google Patents

Abstract

The present invention relates to a motor control method for a washing machine, and an object of the present invention is to provide a motor control method for a washing machine capable of determining whether a process for cooling a motor is required without using a temperature sensor.

In addition, another object of the present invention is to provide a motor control method of a washing machine that can prevent the performance degradation of the washing machine during the cooling process of the motor.

To this end, the present invention calculates a temperature estimation coefficient that is a reference for determining whether the motor is overheated by using the amplitude of the motor and the operation rate of the motor, and decreases the operation rate of the motor when the value of the temperature estimation coefficient is greater than or equal to the first reference value. It characterized by performing a motor cooling process to drive by.

Description

Motor control method of washing machine {Motor control method of a washer}

1 is a flowchart illustrating a motor cooling method of a washing machine according to the prior art.

2 is a cross-sectional view showing the configuration of a washing machine according to an embodiment of the present invention.

3 is a block diagram illustrating components of the washing machine shown in FIG. 2.

4 is a graph showing a motor driving state of the washing machine in FIG.

5A and 5B are flowcharts illustrating a motor cooling method of the washing machine shown in FIG. 2.

FIG. 6 is a graph showing values of the temperature estimation coefficient with time shown in FIGS. 5A and 5B.

Explanation of symbols on the main parts of the drawings

12: washing tub

16: pulsator

17: drive motor

18: power train

30: micom

33: motor drive unit

The present invention relates to a motor control method of a washing machine, and more particularly, to a motor control method of a washing machine that can prevent the motor from overheating.

In general, a washing machine performs washing strokes, rinsing strokes, and dehydrating strokes by rotating a rotating tub and a pearl shader by using a driving force of a motor, and putting laundry water and laundry together in a rotating tub and then agitating them. Washing and washing by using the friction of the rotating tub. The washing machine has a series of washing operations, washing, rinsing, and dehydration, all of which are performed by forward, reverse, and high speed rotation by the motor, and the motor is driven under heavy load during the series of washing operations.

When the motor is overloaded, there is a risk of overheating of the motor and damage or malfunction of the motor. Therefore, a method for preventing overheating of the motor is required. As a method for preventing overheating of a motor according to the related art, as shown in FIG. 1, when power is first supplied to a washing machine, the laundry is put in, and a washing administration signal is input, the microcomputer receives the washing water according to the input signal. Water is supplied to drive the motor to proceed with the washing. (S10)

During washing, the load is applied to the motor, and the load causes overheating of the motor. The temperature of the motor is sensed by using a temperature sensor attached to the heat sink to determine the degree of overheating of the motor. (S20)

In order to determine whether the temperature of the motor is overheated, it is determined whether the temperature is higher than the predetermined standard temperature (about 80 ~ 90 ℃). (S30) If the temperature of the motor is not higher than the standard temperature, the motor is being driven. The motor is driven while maintaining the existing operation rate. (S50)

 On the other hand, when the temperature of the motor is higher than the standard temperature, the operation rate of the motor is set to be low. (S40) If the operation rate of the motor is reset, the remaining operation is performed by driving the motor according to the set operation rate.

 As shown in FIG. 1, when the temperature of the motor is higher than the standard temperature, the operation rate of the motor is set low or the motor operation is stopped until the temperature of the motor reaches a stable temperature, thereby preventing overheating of the motor. It is described in detail in Korean Unexamined Patent Publication No. 1999-19044.

However, the conventional motor control method of the washing machine for preventing overheating of the motor is set by lowering the operation rate of the motor in order to lower the temperature of the motor. There was a problem that the washing time is unnecessarily increased when the operation of the motor is stopped until the temperature is lowered to a safe temperature.

In addition, since the temperature sensor is used to determine whether the motor is overheated, there is a problem in that component costs increase due to the use of the temperature sensor.

The present invention is to solve the above problems, an object of the present invention is to provide a motor control method of a washing machine that can determine whether the process of cooling the motor is required without using a temperature sensor.

In addition, another object of the present invention is to provide a motor control method of a washing machine that can prevent the performance degradation of the washing machine during the cooling process of the motor.

The present invention for achieving the above object is characterized by calculating a temperature estimation coefficient which is a criterion for determining whether the motor is overheated, and performing a cooling process of the motor in accordance with the temperature estimation coefficient.

In addition, the temperature estimation coefficient is obtained by adding the temperature estimate coefficient stored in the control unit to the motor amplitude * motor operation rate) / 128 to obtain an intermediate temperature estimation coefficient, and calculating the intermediate temperature estimation coefficient from the intermediate temperature estimation coefficient. Subtract 64 'and store the result as the temperature estimation coefficient.

In addition, the calculation of the temperature estimation coefficient is characterized in that it is performed repeatedly at a constant cycle.

The cooling process of the motor may determine whether the temperature estimation coefficient is greater than or equal to a first reference value preset when a predetermined time elapses after driving the motor, and predetermined cooling when the temperature estimation coefficient is greater than or equal to a first reference value. During the process time, the motor is driven to decrease the operation rate of the motor than during normal operation, and the cooling process of the motor is terminated when the cooling process time elapses or when the temperature estimation coefficient is less than the second preset value. It is done.

In addition, the cooling process time, characterized in that '(temperature estimation coefficient -880) / 2'.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

2 and 3, the washing machine according to the embodiment of the present invention is installed inside the main body case 10 so as to rotate in the water tank 11 and the water tank 11 for fresh water to be washed. The washing tank 12 is provided. The water tank 11 is supported by the suspended state of the outer surface through the suspension device 13. In addition, a water supply device 14 having a water supply pipe 14a and a water supply valve 14b provided at an upper portion of the water tank 11 to supply washing water into the water tank 11 of the washing machine, and the water tank 11 It includes a drain 15 having a drain pipe (15a) and a drain valve (15b) is installed in the lower portion of the water tank 11 to discharge the filled washing water to the outside.

In the washing tank 12, a pulsator 16 is installed to generate washing water while rotating forward and reverse. And the lower part of the water tank 11 is provided with a driving device for rotating the washing tank 12 and the pulsator 16. The driving device is a power transmission device for transmitting power to the drive motor 17 and the driving motor 17 to generate rotational force by applying power to the pulsator 16 and the washing tank 12 simultaneously or selectively ( 18 and a belt 19 connected between the drive motor 17 and the power transmission device 18 to mediate power transmission.

In another aspect, the present invention is to detect the water level of the water tank (11), and the function of detecting the vibration of the water tank (11) in order to maintain an appropriate level for the amount of laundry in the washing tank 12 in the process of performing the washing administration. It is provided with a composite sensing device 20 that can be performed together.

In addition to the key input unit 31 for inputting the washing operation signal for a series of washing administration, the microcomputer 30 for controlling the overall washing administration so that washing is performed according to the driving signal input from the key input unit 31, and a washing machine. It further includes a power supply unit 32 for supplying power, and a motor drive unit 33 for driving the drive motor 17 to forward or reverse rotation by the control signal of the microcomputer 30.

The driving motor 17 generates a rotational force by repeating the forward and reverse rotations under the control of the motor driving unit 33. The driving motor 17 is not continuously driven during the washing stroke, but has a constant period for a predetermined time within a period. It will only be driven and stopped for the rest of the time. In FIG. 4, the driving state of the driving motor 17 with respect to time is shown in relation to power. When the driving period T of the driving motor 17 is set to 32 seconds, the driving motor is within one period T. (17) is divided into ON TIME (OFF) when the drive is stopped (OFF TIME). In addition, since the driving motor 17 is not always driven at a constant rotation speed but is operated by increasing or decreasing the rotation speed according to the rotational force required for the washing stroke, the power of the driving motor 17 is also driven by the driving period T of the driving motor 17. Will be different.

A motor cooling process of the washing machine shown in FIG. 2 will be described with reference to FIGS. 5A and 5B.

First, power is supplied to the washing machine through the power supply unit 32 for washing. Then, the laundry to be washed is put into the washing tank 12, and then operation signals for a series of washing administrations to be washed through the key input unit 31 are washed. If input, the microcomputer 30 starts the water supply by controlling the water supply device 14 by a predetermined program. When it is determined that the water supply is completed according to the amount of washing water required, the microcomputer 30 controls the motor driving unit 33 to rotate the driving motor 17 forward and reverse and the rotational force of the driving motor 17. The washing stroke is transmitted to the pulsator 16 and the washing tank 12 so that the laundry in the washing tank 12 is washed by the water flow friction force. (S100)

The load is applied to the drive motor 17 while the washing stroke is in progress, and overheating occurs in the drive motor 17 by the load, and the load acting on the drive motor 17 during the washing or rinsing process. It is caused by washing the laundry having high absorption rate, such as a towel, or by washing the laundry 12 due to excessive water level or water flow friction, and it is necessary to determine whether the driving motor 17 is overheated.

In the present invention, a new parameter called a temperature estimation coefficient is calculated as a criterion for determining whether the driving motor 17 is overheated, and the washing cooling process is determined according to the value of the temperature estimation coefficient. First, when the washing operation is started by the above process, the temperature estimation coefficient is initialized to '0' and stored in the microcomputer 30 (S200). The temperature estimation coefficient is then driven for each driving cycle T of the driving motor 17. In this case, the driving period (T) is set to 32 seconds.

The calculation method of the temperature estimation coefficient is shown in FIG. 5B. First, the operation rate of the drive motor 17 is calculated. The driving ratio of the driving motor 17 is a ratio of the on time when the driving motor 17 is driven for one period T, that is, 32 seconds, in the graph shown in FIG. 4. On time time + off time time of the drive motor) * 100 '(S310).

In addition, the measurement duty DUTY of the driving motor 17 is sensed. The measurement duty of the driving motor 17 refers to the power of the driving motor 17, that is, the amplitude at the time of driving the motor 17 in FIG. 4 (S320).

When the operation rate and the measurement duty are obtained, the intermediate temperature estimation coefficient is obtained by adding the measurement temperature of the driving motor * operation rate of the driving motor) / 128 to the existing temperature estimation coefficient stored in the microcomputer 30. In the first cycle, the value initialized in step 200 will be substituted into the temperature estimation coefficient (S300).

When the intermediate temperature estimation coefficient has been calculated, the intermediate temperature estimation coefficient is subtracted from the 'intermediate temperature estimation coefficient / 64', and the value becomes a new temperature estimation coefficient and stored in the microcomputer 30 as a temperature estimation coefficient.

The flow returns to step 310 again to calculate the operation rate and measurement duty of the drive motor 17 in the next cycle (33 to 64 seconds), and the new temperature estimation coefficient becomes the temperature estimation coefficient calculated in the first cycle. Calculate the coefficients.

As described above, if the processes of steps 310 to 340 are repeated for each drive cycle T of the driving motor 17, the values of the temperature estimation coefficients calculated in the previous drive cycles are accumulated in the calculation of the next drive cycle. As time goes by, the value of the temperature estimation coefficient gradually increases, but after a certain time, the increase decreases. Since the change of the temperature estimation coefficient value with time shown in FIG. 6 is similar to the temperature change of the drive motor 17 with time, it is possible to determine whether the drive motor 17 is overheated by the value of the temperature estimation coefficient. .

When the driving of the driving motor 17 starts as the start of the washing stroke, it is determined whether 30 minutes have elapsed since the driving of the driving motor 17 while repeating the calculation of the temperature estimation coefficient in a 32 second cycle as described above. If the driving time of the driving motor 17 has not elapsed for 30 minutes, the driving motor 17 is less likely to overheat, and only the calculation of the temperature estimation coefficient is repeated while maintaining the current driving state of the driving motor 17. (S300)

If the driving time of the driving motor 17 has elapsed 30 minutes, it is determined whether the temperature estimation coefficient calculated so far is 1000 or more. (S500) The driving motor 17 depends on whether the temperature estimation coefficient is 1000 or more. ) If the temperature estimation coefficient is less than 1000, it is assumed that the driving motor 17 is not overheated and the remaining stroke is performed without any further action. (S1100, S1200)

If the temperature estimation coefficient is 1000 or more, it is determined that the driving motor 17 is in an overheated state and the cooling process of the driving motor 17 should be performed. First, a time for operating the cooling section is calculated. The cooling section operation time can be obtained as '(temperature estimation coefficient -880) / 2', and the cooling section operation time is limited from 1 minute to 5 minutes. If the cooling section operation time is less than 1 minute, if it is more than 5 minutes, the operation is limited to 5 minutes. (S600)

When the cooling section operation time is determined, the cooling process of the drive motor 17 is performed. During the cooling process, the drainage and the water supply are stopped, and the driving motor 17 is operated by turning on the motor for 17 seconds at 47 RPM and turning it off for 25 seconds. That is, the driving motor 17 is operated by reducing the operation rate by increasing the OFF time as compared with normal operation.

While the cooling process of the drive motor 17 is in progress, the temperature estimation coefficient is continuously calculated and stored in the microcomputer 30 (S800).

The microcomputer 30 determines whether the cooling section operation time of the driving motor 17 has elapsed or the temperature estimation coefficient has been reduced to 900 or less, and if it is not applicable, the cooling process continues. If the above condition is met, the cooling process is terminated and the driving motor 17 is controlled to be driven at a normal operation rate. (S1000, S1100)

 And the laundry is terminated by performing the remaining administration. (S1200)

As described in detail above, according to the motor control method of the washing machine according to the present invention, it is possible to determine whether the driving motor is overheated by the temperature estimation coefficient without using the temperature sensor.

In addition, it is possible to improve the driving efficiency by driving the motor for a predetermined time without stopping the driving motor in the cooling process, and returning the operating rate of the motor to the normal state when the cooling process is completed.

Claims (5)

Calculate the temperature estimation coefficient that is the standard for judging whether the motor is overheated, The motor control method of the washing machine for performing a cooling process of the motor corresponding to the temperature estimation coefficient. The method of claim 1, The temperature estimation coefficient is The intermediate temperature estimation coefficient is obtained by adding '(motor amplitude * motor operation rate) / 128' to the temperature estimation coefficient stored in the controller. Motor control method of a washing machine, characterized in that by subtracting the 'intermediate temperature estimation coefficient / 64' from the intermediate temperature estimation coefficient and storing the result as the temperature estimation coefficient. (Amplitude of the motor: the maximum drive power of the motor during the drive cycle of the motor, Motor operation rate: (motor drive time / motor drive cycle during motor drive cycle) * 100) The method of claim 2, The calculation of the temperature estimation coefficient, the motor control method of the washing machine characterized in that it is performed repeatedly at a constant cycle. The method of claim 1, The cooling process of the motor, When a predetermined time elapses after driving the motor, it is determined whether the temperature estimation coefficient is equal to or greater than the first reference value that is preset. When the temperature estimation coefficient is greater than or equal to the first reference value, the motor is driven to decrease the operation rate of the motor for a predetermined cooling process time than during normal operation. And the cooling process of the motor is terminated when the cooling process time elapses or when the temperature estimation coefficient is equal to or less than a second preset reference value. The method of claim 4, wherein The cooling process time, the motor control method of the washing machine, characterized in that ((temperature estimation coefficient -880) / 2).

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