KR20040046049A - Method for controlling motor of washing machine - Google Patents

Abstract

PURPOSE: A motor control method of a washing machine is provided to prevent damage of a circuit and improve stability and reliability by restricting over current from overload with controlling the duty rate corresponding to the laundry amount and RPM(Revolution Per Minute) in suddenly braking the motor. CONSTITUTION: Sudden braking is performed by plugging in inputting the sudden braking command(S21,S22), and RPM of a motor is compared with the first predetermined RPM(S23). The duty rate is adjusted with detecting time reaching the first predetermined RPM from suddenly braking the motor(S24,S25,S26,S27,S28). Time reaching from the first predetermined RPM to the second predetermined RPM is detected if RPM of the motor reaches the second predetermined RPM(S29,S30). The duty rate is decreased corresponding to the detected time(S31,S32). The duty rate is increased at the initial stage, and decreased slowly in detecting the large amount of the laundry. The duty rate is decreased at the initial stage, and reduced fast in detecting the small amount of the laundry.

Description

Method for controlling motor of washing machine

The present invention relates to a washing machine, and more particularly, to a motor control method of a washing machine.

As shown in FIG. 1, the general washing machine includes a rectifying unit 11 for rectifying commercial AC power, a motor 12 for supplying rotational force to a washing tank or a pearl shader of a washing machine, and a plurality of IGBTs (Insulating Gate Bipolar Transistor). Inverter (Inverter) having a first mode for supplying three-phase (U / V / W) power to the motor 12 or the motor 12 is controlled in reverse phase, that is, the voltage generated by the rotation of the motor The driving unit 13 operating in the second mode to be reversed to the circuit side, the switching mode power supply (SMPS) 14 for transforming and outputting the output of the rectifying unit 11 to a predetermined level (5V), and the motor 12 The speed sensor 15 for detecting the rotational speed of the motor, and the braking resistor Rb and the braking resistor Rb to prevent circuit damage by consuming the generated voltage of the motor 12 reversed by the driver 13 as heat. Rectifier 11 via transistor T1 and braking resistor Rb A drive microcomputer 17 for controlling the driver 13 and the transistor T1 with reference to an output of the voltage detector 16, the speed sensor 15, and the voltage detector 16 for detecting an output voltage level; Is installed on the door side and includes a door switch (not shown), a touch panel or a key input unit for notifying the drive microcomputer 17 to detect the user opening the door, the user interface unit for the user to input various operation commands 18, driving the various loads including the motor 12 to correspond to a user operation command input through the LCD 19, the buzzer 20, and the user interface unit 18 for displaying the washing machine operation state and the like. In order to perform various data communication including the control signal with the drive micom 17 and to detect an abnormality in the power supply voltage through communication with the drive micom 17, a preset warning message Includes a main microcomputer (21) for driving said LCD (19) and buzzer (20) so that the buzzer sound is output.

Referring to the operation of the washing machine configured as described above is as follows.

First, when a user inputs a washing command through the user interface unit 18, the main microcomputer 21 recognizes this and transmits a predetermined control signal to the drive microcomputer 17 so that loads according to a preset washing algorithm are driven.

Therefore, the drive microcomputer 17 operates the drive unit 13 in the first mode to rotate the motor 12 according to the output of the speed sensor 15 to meet the preset washing algorithm, and to load the water supply valve and the drain valve. Drive to wash, rinse and dehydrate.

The main microcomputer 21 controls the LCD 19 according to the current operating state to display the operating state, and the buzzer 20 to generate a warning sound according to the operating state.

On the other hand, during the washing, rinsing, and dehydrating stroke, a case of sudden braking of the motor occurs.

For example, in the case of washing, since the motor uses a method of rotating left and right stirring, for example, to rotate to the left after the right rotation, the current motor must be braked first. Also, in case of operation stop during dewatering and door opening, the current motor must be braked rapidly.

Therefore, when the above-described sudden braking condition occurs, the drive microcomputer 17 first switches the driving unit 13 to the second mode to perform reverse phase braking and controls the transistor T1 to drive the braking resistor Rb. The power caused by the reversed phase braking is consumed by heat, thereby preventing the voltage value from rising to a degree that may cause damage to the internal circuit.

According to the related art, when a sudden braking condition occurs, as described above, the driving unit 13 is switched to the second mode to perform rapid braking by reverse braking, and the motor revolution speed (RPM) at the time of sudden braking is performed. ) To control the duty ratio differently.

That is, it sets the initial duty ratio according to the current RPM and decreases by a certain amount at regular time intervals to perform rapid braking. For example, the initial duty ratio is set to 100 and reduced by '1' every 3ms.

The washing machine according to the related art performs rapid braking by setting the duty ratio by RPM only at the time of sudden braking regardless of the amount of the braking and reducing it by a certain amount at a predetermined interval. Therefore, if the same duty control without considering the amount of capacity is carried out, the current value is excessively increased, and in severe cases, the rated current value is exceeded, which may cause damage to the internal circuit.

Accordingly, an object of the present invention is to provide a motor control method of a washing machine to prevent overcurrent by performing a duty ratio control according to a quantity and RPM during braking of a motor. .

1 is a block diagram showing the configuration of a typical washing machine

2 is a flowchart illustrating a motor control method of a washing machine according to the present invention.

The present invention includes the steps of performing a motor braking according to a sudden braking command, measuring a time required to decelerate to a predetermined rotational speed after a sudden braking, and adjusting the braking duty ratio and the duty ratio reduction interval to fit the measured time. Characterized in that it comprises a step.

Hereinafter, a preferred embodiment of a motor control method of a washing machine according to the present invention with reference to the accompanying drawings in detail as follows.

2 is a flowchart illustrating a motor control method of a washing machine according to the present invention.

As shown in FIG. 2, the present invention first determines whether a sudden braking command is input, that is, whether the main microcomputer 21 or the drive microcomputer 17 detects a door opening during dehydration or a user stop command. (S21).

As a result of the determination (S21), if a rapid braking command is input, rapid braking is performed by the above-described reverse braking (S22).

Subsequently, it is determined whether the current motor RPM reaches the first set RPM 600 (S23).

At this time, since the motor RPM is generally '700' or more during dehydration, the first set RPM may be set to a lower RPM than that.

When the determination result (S23), the current motor RPM has reached the first set RPM, it is determined whether the time (T1) to reach the first set RPM from within the motor sudden braking time is within 3 seconds (S24), within 3 seconds In this case, the duty ratio is set to '70' and is decreased by '1' every 2ms (S25).

On the other hand, if the determination result (S23), 'T1' is not less than 3 seconds, it is determined whether 'T1' is more than 3 seconds and less than 3.6 seconds (S26), if less than 3.6 seconds, the duty ratio to '80' and 4ms intervals Decrease by '1' (S27).

On the other hand, if the determination result (S26), 'T1' is 3.6 seconds or more, the duty ratio is set to '100' and decrease by '1' in 10ms intervals (S28).

'T1' depends on the washing capacity. In other words, as the amount of water increases, the centrifugal force of the washing cloth increases according to the rotation of the washing tub, and accordingly, the time required for deceleration becomes longer. On the contrary, the smaller the amount of water, the shorter the time required for deceleration.

Therefore, if 'T1' is less than 3 seconds, the amount is relatively smaller than that of 3.6 seconds or more, so the duty ratio is '70' and the duty ratio is reduced every 2ms, and 'T1' is more than 3 seconds. If it is within 3.6 seconds, the duty ratio is larger than that of the 3 seconds, that is, '80' and the duty cycle decrease interval is 4ms, and when the 'T1' exceeds 3.6 seconds, the duty ratio is '100'. The duty cycle reduction interval is also longer, with 10ms.

As a result, when the dose is large, the initial duty ratio is increased and decreased slowly. On the contrary, when the dose is small, the initial duty ratio is relatively decreased and the speed is decreased.

Subsequently, rapid braking is performed in any one of the steps S25, S27, and S28, and it is determined whether the current RPM reaches the second set RPM 350 (S29).

When the determination result (S29), the second set RPM is reached, it is determined whether the time (T2) required to reach the second set RPM from the first set RPM is within 4.6 seconds (S30).

As a result of the determination (S30), if the 'T2' is within 4.6 seconds, the duty ratio is set to '40' and reduced by '1' every 2ms (S31).

On the other hand, if the determination result (S300, 'T2' is more than 4.6 seconds, the duty ratio is set to '45' and reduced by '1' every 8ms (S32).

At this time, the steps S31 and S32 are similar to the above-described steps S25, S27, and S28 to increase and slowly decrease the initial duty ratio when the quantity is large. The principle of reducing and decreasing quickly is the same. The current RPM is considerably lower than the initial stage, so the duty ratio is reduced accordingly.

Subsequently, rapid braking is performed in any of the above-described steps S31 and S32, and is terminated when the rapid braking is completed.

The various speed and time-related numerical values described above are applied to one embodiment according to the present invention, which is beyond the technical scope of applying the duty ratio and the duty ratio reduction interval differently according to the core technology, that is, the quantity and the speed. It may be applied differently depending on the characteristics of the washing machine and the motor in the range.

The motor control method of the washing machine according to the present invention adjusts the duty ratio and the duty ratio reduction interval to suit the amount and speed, thereby preventing overcurrent due to overload and thereby preventing damage to circuit components, thereby improving product stability and reliability. It can be effective.

Claims (4)

In the washing machine, Performing motor sudden braking according to a sudden braking command; Measuring a time taken to decelerate to a predetermined rotation speed after the rapid braking; And adjusting the rapid braking duty ratio and the duty ratio reduction interval to correspond to the measured time. According to claim 1, The predetermined rotation speed is a motor control method of the washing machine, characterized in that at least one. According to claim 1, And adjusting the rapid braking duty ratio and the duty ratio reduction interval to correspond to the measured time, so as to increase the duty ratio as the measured time increases. According to claim 1, And adjusting the rapid braking duty ratio and the duty ratio reduction interval so as to correspond to the measured time lengthening the duty ratio reduction interval as the time measured is longer.