KR100539743B1 - Eccentricity load detecting method for washing machine - Google Patents

Abstract

The present invention relates to a method for detecting an eccentric load of a washing machine. In a system with a small amount of change in speed, an eccentric amount can be accurately measured by using a torque shaft current which varies according to the amount of eccentric load. To this end, the present invention provides a washing machine employing a BCD motor driven by an inverter, when the washing machine enters the dehydration mode, detecting the estimated speed and current of the low-pass filtered rotor; Comparing the estimated speed of the rotor with a reference speed and comparing whether the rotation angle is greater than the reference angle when the estimated speed of the rotor is larger than the reference speed; If the rotation angle is greater than the reference angle, initializing the rotation angle, calculating and storing an amplitude of the detected current; After converting the amplitude of the detection current to the amount of eccentricity, a process of outputting the amount of eccentricity after a predetermined time passes.

Description

Eccentric load detection method of washing machine {ECCENTRICITY LOAD DETECTING METHOD FOR WASHING MACHINE}

1 is a view showing a change in the vibration width according to the amount of eccentricity of the washing machine.

Figure 2 is a circuit diagram showing a configuration for one embodiment of a device to which the eccentric load detection of the conventional washing machine is applied.

Figure 3 is a circuit diagram showing the configuration of an embodiment of the apparatus to which the eccentric load detection method of the present invention is applied.

Figure 4 is an operation flow chart for the eccentric load detection method of the present invention washing machine.

The present invention relates to a method for detecting an eccentric load of a washing machine, and more particularly, to an eccentric load detection method of a washing machine capable of accurately measuring the amount of eccentricity by using a torque shaft current that varies according to the load eccentricity in a system with a small speed change. It is about.

Eccentricity of washing machine dehydration not only leads to an increase in the overall washing stroke time due to increased dehydration noise and increased dewatering entry time, but also causes a lot of trouble in performing stable dehydration, and in severe cases, damage to the system. Will bring.

In the washing machine, the amount of eccentricity of the load is measured by using the magnitude of the speed ripple from the speed sensor algorithmically by using the phenomenon that the system vibration shows the speed variation, and then using the magnitude of the speed ripple. When the tube vibrates and the speed fluctuation occurs, the amount of eccentricity increases, and as the amount of the eccentricity increases, the speed fluctuation phenomenon appears as the amplitude of the amplitude increases at the same frequency.

That is, as shown in Figure 1, it can be seen that the vibration period is constant and only the width of the vibration changes according to the amount of eccentricity, if the speed is formulated using this principle, as shown in Equation 1 below.

In addition, the dehydration operation of the washing machine, it is difficult to detect the amplitude of the speed fluctuation during the dehydration operation, because the dehydration operation to reach the normal speed by repeating the constant speed, acceleration, it is difficult to detect the magnitude of the amplitude because there is no acceleration component during the constant speed Although easy to do, the dehydration operation is difficult to detect the magnitude of the amplitude because most of the acceleration component is included.

Therefore, in order to detect the vibration amount irrelevant to the acceleration component, the derivative of Equation 1 is as follows.

Here, assuming that the maximum value when t = t1, and the minimum value when t = t2, the difference between the two values is the maximum amplitude difference with respect to the derivative of the speed. Therefore, the basic equation of the eccentricity detection algorithm is shown in Equation 3 below.

That is, the conventional eccentric load detection method of the washing machine, by using the 720 degree detection method so that the microcomputer can be implemented using the equation (3), the maximum value and the minimum value on the basis of 12 sensor signals in one revolution of the washing tank By determining the difference between the operation of the laundry cloth in the washing tank according to the conditions.

2 is a circuit diagram showing the configuration of a device to which the eccentric load detection of a conventional washing machine is applied.

As shown in FIG. 2, the rectifying and smoothing unit 11 rectifies and smoothes the AC power source AC; An inverter unit (12) for controlling the speed of the rotor by applying the rectified and smoothed voltage and current to a BC motor (13) with a variable frequency and a voltage having a variable amplitude; A microcomputer (14) for detecting a current applied to the BCD motor (13) to detect the position of the rotor and to control the rotation speed; And a pulse width modulator 15 that modulates the output pulse width of the control signal of the microcomputer 14 to turn on / off the inverter unit 12.

The rectifying unit 1 rectifies and smoothes the input AC power supply AC to the inverter unit 12, and the inverter unit 12 is turned on by a gate signal which is a drive signal of the pulse width modulating unit 15 to be converted. Applied three-phase voltage is applied to the BC motor (13).

Accordingly, the BCD motor 13 rotates, and the position detection unit 14a including a hall sensor or an encoder detects the position of the BCD motor 13 and outputs a voltage value accordingly. Outputs a control signal that allows the BCD motor 13 to rotate at a desired speed by calculating the speed of the BCD motor 13 with the voltage value and comparing it with a preset reference speed, and modulating the pulse width. The unit 15 converts the level of the output control signal of the microcomputer 14 and supplies it to the inverter unit 12.

The microcomputer 14 detects 720 degrees based on the Hall sensor measurement signal of the BCD motor 13 to determine the difference between the maximum value and the minimum value based on 12 sensor signals in one rotation of the washing tank. To detect the eccentric load

In the voltage control system as shown in FIG. 2, since the change in speed is large, the eccentric amount can be measured by using the change in speed. However, in the current and speed control system as shown in FIG. There is a problem in that the amount of change information does not accurately measure the amount of eccentricity.

Accordingly, the present invention was devised to solve the above problems, and in an system with a small amount of change in speed, an eccentric load of a washing machine capable of accurately measuring the amount of eccentricity using a torque shaft current which varies according to the amount of eccentricity of the load. The purpose is to provide a detection method.

The present invention for achieving the above object, in a washing machine employing a BCD motor driven by an inverter, when the washing machine enters the dehydration mode, the process of detecting the estimated speed and current of the low-pass filtered rotor and; Comparing the estimated speed of the rotor with a reference speed and comparing whether the rotation angle is greater than the reference angle when the estimated speed of the rotor is larger than the reference speed; If the rotation angle is greater than the reference angle, initializing the rotation angle, calculating and storing an amplitude of the detected current; After converting the amplitude of the detection current to the amount of eccentricity, it is characterized in that the process of outputting the amount of eccentricity after a predetermined time.

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

Apparatus to which the eccentric load detection method of the washing machine of the present invention is applied are the same as in FIG.

) 및 토오크분 전압(

)으로 출력하는 동기/정지 좌표 변환부(37)와; 동기 릴럭턴스 모터(SynRM)의 회전시 검출되는 3상 전류를 2상 전류로 변환시켜 출력하는 2상 전류 발생부(40)와; 상기 2상 전류를 회전 좌표계로 변환시켜 상기 실제 토오크분 전류(

) 및 자속분 전류(

)로 출력하는 정지/동기 좌표 변환부(41)와; 상기 동기/정지 좌표 변환부(41)의 출력과 2상 전류 및 기준 속도(

)를 입력받아 회전자의 위치 및 속도를 추정하는 속도/위치 추정 연산부(42)로 구성된 것으로, 이와 같이 구성된 본 발명의 동작 및 작용을 설명하면 다음과 같다.As shown in FIG. 3, the apparatus to which the eccentric load detection method of the washing machine of the present invention is applied includes a first subtractor 31 which outputs an error by comparing the reference speed w _m ^* with the estimated speed w _m . ; A second subtractor 34 for comparing the reference torque current and the actual torque current to compensate for the error and outputting an error; A third subtractor 33 which outputs an error by comparing the reference flux current and the actual flux current; The reference flux current and the torque current of the fixed coordinate system as reference magnetic flux currents (or torque currents) for compensating for errors by receiving the outputs of the second and third subtractors 34 and 33.

) And torque voltage (

A synchronization / stop coordinate converter 37 for outputting to); A two-phase current generator 40 for converting the three-phase current detected when the synchronous reluctance motor SynRM is rotated into two-phase current and outputting the two-phase current; The two-phase current is converted into a rotational coordinate system so that the actual torque current (

) And flux current (

A stop / synchronous coordinate conversion unit 41 outputting the same; The output of the synchronous / stop coordinate converter 41 and the two-phase current and reference velocity (

) Is composed of a speed / position estimation calculation unit 42 for estimating the position and speed of the rotor, the operation and operation of the present invention configured as described above are as follows.

)는 그 제1 감산부(31)의 비반전 단자로 입력된다.First, the rotor estimation speed w _m of the synchronous reluctance motor SynRM output from the speed / position estimation calculator 42 is input to the inverting terminal of the first subtraction unit 31, and the reference speed (

) Is input to the non-inverting terminal of the first subtraction section 31.

)가 비교된 오차값을 입력받아 그 오차값을 보상하여 기준 토오크분 전류(

)를 출력한다.As a result, the first PI control unit 32 determines the estimated speed w _m and the reference speed in the first subtracting unit 31.

) Receives the compared error value and compensates the error value to obtain the reference torque current (

)

)는 정지/동기 좌표 변환부(41)의 출력 전류중 실제 토오크분 전류(

)와 함께 제3 감산부(33)에 입력되어 비교된후 출력된다. The reference torque current (

) Represents the actual torque current of the output current of the stop / synchronous coordinate converter 41.

) Is input to the third subtraction unit 33 and compared, and then output.

)을 동기/정지 좌표 변환부(37)로 출력한다.At this time, the third subtractor 33 outputs the compared error to the third PI controller 36, and the third PI controller 36 compensates for the compared error. Reference torque voltage for minute current (

) Is output to the synchronization / stop coordinate conversion unit 37.

)와 상기 정지/동기 좌표 변환부(41)의 출력인 실제 자속분 전류(

)를 비교하여 그에 따른 오차를 제2 피아이(PI)제어부(35)로 출력한다.In addition, the second subtracting section 34 has a reference flux current (

) And the actual magnetic flux current that is the output of the stop / synchronous coordinate converter 41

) Is compared and the error is output to the second PI control unit 35.

)을 출력하고, 상기 제1 피아이제어부(32)의 출력인 기준 토오크분 전류(

)는 상기 정지/동기 좌표 변환부(41)의 출력인 실제 토오크분 전류(

)와 비교된다.Accordingly, the second eye controller 35 may use the reference magnetic flux voltage of the reference magnetic flux current to compensate for the error compared by the second subtractor 34.

) Is outputted, and the current for the reference torque that is the output of the first eye controller 32 (

Is the actual torque current (the output of the stop / synchronous coordinate conversion unit 41)

).

)을 동기/정지 좌표 변환부(37)로 출력한다.As a result, the third eye controller 16 uses the reference torque voltage of the reference torque current to compensate for the compared error (

) Is output to the synchronization / stop coordinate conversion unit 37.

) 및 속도/위치 추정 연산부(42)의 출력 또한 상기 동기/정지 좌표 변환부(37)에 입력된다.At this time, the reference flux voltage (the output of the second eye controller 35)

) And the output of the speed / position estimation calculator 42 are also input to the sync / stop coordinate converter 37.

) 및 기준 토오크분 전압(

)이 고정좌표계의 3상 전압(Vas, Vbs, Vcs)으로 변환되고, 그 3상 전압을 입력받는 인버터부(39)에 의해 회전하는 동기 릴럭턴스 모터(SynRM)의 검출된 3상 전류는 2상 전류 발생부(40)로 입력되어 고정좌표계의 자속분 전류(

) 및 토오크분 전류(

)를 출력한다.Reference flux voltages of the alpha (α) and beta (β) axes of the fixed coordinate system that are outputs of the synchronization / stop coordinate conversion unit 37 (

) And reference torque voltage (

) Is converted into three-phase voltages Vas, Vbs, and Vcs of the fixed coordinate system, and the detected three-phase current of the synchronous reluctance motor SynRM rotating by the inverter unit 39 receiving the three-phase voltage is 2 The magnetic flux component current of the fixed coordinate system input to the phase current generator 40

) And torque current (

)

)와 기준 자속분, 토오크분 전압(

) 및 기준 속도(w_m ^*)는 상기 속도/위치 추정 연산부(42)로 입력되어 자속각(θ)에 대한 사인, 코사인값(sinθ, cosθ) 및 회전자의 추정 속도(

)로 출력된다.Thereby, the magnetic flux component and torque component current of the fixed coordinate system (

), Reference flux and torque

) And the reference velocity (w _m ^* ) are input to the velocity / position estimation calculator 42 to estimate the sine, cosine value (sinθ, cosθ) for the magnetic flux angle θ, and the estimated velocity of the rotor (

Will be displayed.

Here, the present invention measures the eccentric load by the variation of the current detected by filtering the estimated speed of the rotor through a low pass filter, which will be described in detail.

4 is a flowchart illustrating an eccentric load detection method of the washing machine of the present invention.

As shown in FIG. 4, when the washing machine enters the dehydration mode, a first process of detecting an estimated speed and a current of the low-pass filtered rotor; Comparing the estimated speed of the rotor with a reference speed, and if the estimated speed of the rotor is smaller than the reference speed, resetting the rotation speed by initializing the rotation angle and current without measuring an eccentric amount; A third step of comparing the estimated speed of the rotor with a reference speed and comparing the rotation angle with the reference speed if the estimated speed of the rotor is larger than the reference speed; A fourth step of initializing the rotation angle if the rotation angle is greater than the reference angle, and then calculating and storing the amplitude of the detected current; A fifth process of converting the amplitude of the detected current into an eccentric amount and outputting the eccentric amount after a predetermined time; If the rotation angle is smaller than the reference angle, a sixth process of comparing the difference between the instantaneous current maximum value and the minimum value with the previously calculated difference between the instantaneous current maximum value and the minimum value and storing the large difference value as the detection current The operation of the present invention will be described.

First, when the washing machine enters the dehydration mode, it detects the estimated speed of the rotor and the low pass filtered current using the speed control device as shown in FIG. 3, and the current is converted into a low pass filter having a high cut off frequency. Detection is made through a low pass filter with a low cut off frequency.

Then, by comparing the estimated speed of the rotor with the reference speed, if the estimated speed of the rotor is less than the reference speed, after initializing the rotation angle and current without measuring the amount of eccentricity, the estimated speed of the rotor is measured again. .

Here, the reference speed is the speed most suitable for the measurement of the amount of eccentricity, and is preset by experiment.

On the other hand, by comparing the estimated speed of the rotor with the reference speed, if the estimated speed of the rotor is greater than the reference speed, and if the rotation angle is greater than the reference angle, if the rotation angle is greater than the reference angle based on the comparison result After initializing the rotation angle, the amplitude of the detection current is calculated and stored. The amplitude of the current is output by passing one current through a low pass filter having a high cut off frequency and a low pass filter having a low cut off frequency. Measure the difference between the two currents.

If the rotation angle is smaller than the reference angle, the difference value between the instantaneous current maximum value and the minimum value is compared with the previously calculated difference between the instantaneous current maximum value and the minimum value, and the large difference value is stored as the detection current.

Then, after converting the amplitude of the detected current into an eccentric amount, the eccentric amount is output after a predetermined time, and if the predetermined time has not passed, the difference between the instantaneous current maximum value and the minimum value is calculated as the previously calculated instantaneous current maximum value. Compared with the difference between and the minimum value, the large difference value is stored as the detection current, and the above-described operation is repeated.

In other words, when the washing machine is in the dehydration mode in which the washing machine rotates at a constant speed, the amount of eccentricity of the load is detected as the amount of change in the current, thereby measuring the correct amount of eccentricity.

As described in detail above, the present invention has an effect of accurately measuring the amount of eccentricity using a torque shaft current which varies according to the amount of eccentricity of a load in a system having a small amount of change in speed.

Claims (5)

In the washing machine employing a BCD motor driven by an inverter, Detecting the estimated speed and current of the low pass filtered rotor when the washing machine enters the dehydration mode; Comparing the estimated speed of the rotor with a reference speed and comparing the rotation angle with the reference speed if the estimated speed of the rotor is greater than the reference speed; When the rotation angle is greater than the reference angle, initializing the rotation angle, and then calculating and storing the amplitude of the detected current; And converting the amplitude of the detection current into an eccentric amount, and then outputting the eccentric amount after a predetermined time. According to claim 1, If the rotation speed is less than the reference speed, the eccentric load detection method of the washing machine comprising the step of measuring the rotation speed again by initializing the rotation angle and current without measuring the amount of eccentricity. The detection current according to claim 1, wherein when the rotation angle is smaller than the reference angle, a difference value between the instantaneous current maximum value and the minimum value is compared with a previously calculated difference between the instantaneous current maximum value and the current minimum value, and a large difference value is detected. Eccentric load detection method of a washing machine comprising the step of storing as. The method of claim 1, wherein after a predetermined time has passed after converting the amplitude of the detected current into an eccentric amount, a difference between the instantaneous current maximum value and the minimum value is compared with a previously calculated difference between the instantaneous current maximum value and the minimum value. And storing the large difference value as the detection current. The method of claim 1, wherein the calculating and storing the amplitude of the detection current comprises: Eccentric load of the washing machine, characterized by measuring the amplitude of the current by using a difference between the two currents output by passing one current through the low pass filter having a high cut off frequency and the low pass filter having a low cut off frequency Detection method.

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