JP4961409B2 - Drum washing machine - Google Patents

Description

  The present invention relates to a drum type washing machine.

  In a conventional drum type washing machine, the amplitude of the motor current detected by the motor current detection circuit while the drum is driven to rotate at a rotational speed at which the centrifugal force acting on the laundry in the drum is greater than the gravity. A device for judging the degree of unbalance of laundry stuck to a drum from a variation value is provided (see Patent Document 1).

Japanese Patent No. 3332769

  However, even if it is possible to detect an unbalanced state by the laundry being biased to the drum and sticking to the drum, the tangled laundry does not stick to the drum and rolls. There is no mention of how to detect a condition.

  If the rotation speed of the drum is increased without detecting this state, when the centrifugal force acting on the laundry becomes large, the dumpling-like laundry may suddenly stick to the drum, which may cause a large vibration and noise. .

  Therefore, the present invention solves this problem by detecting an unbalanced state caused by the laundry being in a dumpling shape and preventing drums from generating large vibrations and noises in advance. The purpose is to provide.

  The drum type washing machine of the present invention comprises a drum rotatably installed in an outer tub, a motor for driving the drum, a magnetic pole position detecting means for detecting a magnetic pole position of the motor, and a rotational speed of the motor. Rotational speed detection means for detecting, motor control command generating means for outputting a current command for controlling the motor current from the rotational speed detected by the rotational speed detection means, and magnetic pole position detected by the magnetic pole position detection means Motor control means for controlling the motor based on the current command, an offset addition means for outputting a second current command by adding a variable offset value to the current command, and a lifter attached to the drum. And a predetermined frequency component determined from the rotational speed detected by the rotational speed detection means is extracted from the second current command, and then the frequency component is Frequency component extraction means for outputting the third current command amplified in, a corrected second current command in which the phase of the signal in the second current command is shifted by a predetermined amount, the corrected second current command, and the third current command Difference signal generating means for outputting a difference signal obtained by the difference between the first current command, a third current command fluctuation value obtained from a difference between a maximum value and a minimum value of the third current command, and a maximum value and a minimum value of the difference signal. And an unbalance detecting means for detecting an unbalanced state of the drum in accordance with a difference signal fluctuation value obtained from a difference between the drum and the drum.

  The drum type washing machine of the present invention is in a state where the dumped laundry rolls without sticking to the drum at a rotational speed at which the centrifugal force acting on the laundry in the drum is greater than the gravity. In this case, it is possible to detect this, and it is possible to prevent the generation of large vibrations and noises in advance, so that a drum-type washing machine with high safety can be realized.

  Examples according to the present invention will be described below.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 2 is a block diagram of the motor drive device of this embodiment, FIG. 3 is an external view of the drum type washing machine of this embodiment, and FIG. 4 is an external view of the drum of this embodiment.

  3 and 4 show the structure of the drum type washing machine and the structure of the drum according to the present embodiment. The drum 31 is a rotatable drum 31 that contains laundry, an outer tub 32 that includes the drum 31, and an outer drum 32. The drum 31 includes a casing 32 that encloses the tub 32, and the drum 31 has a structure in which three lifters 41 to 43 for lifting the laundry at the time of washing are attached at equal intervals every 120 degrees.

  With reference to FIG. 2, the motor driving apparatus of this embodiment will be described. A diode 21 that converts AC power into DC power, a smoothing capacitor 22 that removes ripples from DC power, a motor 25 that rotationally drives the drum 31, and a DC motor that converts DC power into AC power. , An inverter circuit 24 to be supplied to the microcomputer 26, a microcomputer 26 which gives the inverter circuit 24 a PWM control signal 28 for driving the motor 25, a DC power source 23 for driving the microcomputer 26, and a magnetic pole position of the motor 25 are detected. Magnetic pole position detecting means 27 is provided.

  The microcomputer 26 controls the motor 25 to the target rotational speed according to a predetermined program based on the output signal of the magnetic pole position detecting means 27.

  Next, processing contents of a program built in the microcomputer 26 according to the present invention will be described.

  FIG. 1 is a block diagram of a program built in the microcomputer 26.

  First, the procedure for controlling the rotational speed of the motor 25 to the target rotational speed will be described.

  The rotation speed detection means 11 detects the rotation speed of the motor 25 by using the magnetic pole position detected from the magnetic pole position detection means 27 as an input and calculating the amount of movement of the magnetic pole position per unit time.

  The motor control command generation means 12 is realized using a PI controller, and generates a current command from the difference between the rotation speed of the motor 25 detected from the rotation speed detection means 11 and the target rotation speed. In this embodiment, the current command corresponds to the torque current component Iq * of the motor current command.

  In this embodiment, the motor control command generation means 12 is configured using a PI controller. However, other than the PI controller, such as referring to a table storing the output value of Iq * with respect to the rotational speed of the motor 25. It is also possible to use this algorithm.

  The motor control means 13 controls the motor 25 to the target rotational speed by giving a PWM control signal 28 to the inverter circuit 24 based on the magnetic pole position and the current command.

  Next, the rotation speed fluctuation | variation when putting the laundry and driving the motor 25 is demonstrated using FIGS.

  FIG. 5 shows the state of the laundry 51 in the drum 31 in a state in which the centrifugal force acting on the laundry rotates at a rotational speed greater than the gravity and the laundry 51 is stuck to the drum 31 without unbalance. The rotation speed 52 of the motor 25 is shown. Under this condition, there is no fluctuation in the rotation speed, and it becomes a constant value.

  FIG. 6 shows the rotation speed when the laundry 51 is biased and rotating on the drum 31, and a frequency component corresponding to one rotation of the drum is generated as the rotation speed fluctuation 61.

  FIG. 7 shows a case where the laundry 51 rolls in the form of a dumpling, and the frequency component synchronized with the timing of being caught by the lifters 41 to 43 attached to the drum 31 is the rotational speed variation 71. It happens.

  When N lifters are attached to the drum at equal intervals, rotation speed fluctuations including frequency components corresponding to drum N rotation occur. In the drum 31 of this embodiment, three lifters 41 to 43 are attached at equal intervals every 120 degrees. For this reason, a rotational speed fluctuation 71 including a frequency component corresponding to three drum rotations occurs.

  These frequency components appear in the current command as well. Therefore, in this embodiment, these frequency components are extracted from the current command, and the unbalanced state is detected by comparing their amplitudes. Hereinafter, as shown in FIG. 8, the current command 84 will be described as including a constant value component 81, a frequency component 82 corresponding to one drum rotation, and a frequency component 83 corresponding to three drum rotations.

  Next, a procedure for extracting a constant value component, a frequency component corresponding to one drum rotation, and a frequency component corresponding to three drum rotations from the current command will be described.

  First, a method for removing the constant value component from the current command will be described.

  The offset adding means 14 calculates a current command average value within one drum rotation cycle time as preprocessing. Specifically, it is calculated by dividing the sum of the current commands in the drum one rotation cycle time by the drum one rotation cycle time. This current command average value appears as an offset value 91 as shown in FIG. Therefore, as post-processing, the second current command 92 from which the constant value component is removed is obtained by subtracting the offset value 91 from the current command 84.

  Next, a method for extracting a frequency component corresponding to one rotation of the drum 31 will be described.

  As shown in FIG. 10, the frequency component extraction means 15 uses the low-pass filter from the second current command 92 to attenuate the frequency component corresponding to three drum rotations and extract mainly including the frequency component corresponding to one drum rotation. The signal 101 is extracted. The time constant of the low-pass filter may be set to a period time corresponding to three drum rotations in order to attenuate a frequency component corresponding to three drum rotations. When r is the motor rotation speed when the motor rotates r in 1 second, the cycle time corresponding to 3 drum rotations, that is, the time constant of the low-pass filter is (1 ÷ r) ÷ 3 seconds.

  Here, since the frequency component corresponding to one rotation of the drum is also attenuated by the attenuation action of the low-pass filter, in order to correct this, the extraction signal 101 is multiplied by the amplitude gain. In this embodiment, the value of the amplitude gain is set so that the amplitude of the frequency component corresponding to one rotation of the drum matches between the second current command 92 and the extraction signal 101, and the third current obtained by correcting the attenuation by the low-pass filter. Command 102 is output.

  In the present embodiment, the frequency component extraction means 15 is configured using a low-pass filter, but it can also be realized using a calculation method such as moving average processing.

  Next, a method for extracting a frequency corresponding to three rotation cycles of the drum 31 will be described.

  The difference signal generation means 16 outputs a difference signal by taking the difference between the second current command 92 and the third current command 102. The second current command 92 includes a frequency component corresponding to three drum rotations and a frequency component corresponding to one drum rotation, and the third current command 102 includes a frequency component corresponding to one drum rotation. For this reason, the differential signal is a signal including only a frequency component corresponding to three rotations of the drum.

  Here, since the low-pass filter used in the frequency component extraction unit 15 has an action of delaying the phase of the signal, the phase of the signal in the third current command is delayed from the phase of the signal in the second current command. Therefore, the difference signal generation means 16 corrects the second current command by shifting the phase of the signal in the second current command so that the phases of both signals coincide. As shown in FIG. 11, the difference signal 112 including only the frequency component corresponding to the rotation of the drum 3 is output based on the difference between the corrected second current command 111 and the third current command 102.

  Due to the frequency characteristics of the low-pass filter of this embodiment, the phase of the signal in the third current command is delayed by approximately 60 degrees. Therefore, in this embodiment, the phases of both signals are matched by delaying the phase of the signal in the second current command by approximately 60 degrees.

  By the above procedure, the third current command 102 including the frequency component corresponding to one drum rotation and the difference signal 112 including the frequency component corresponding to three drum rotations can be extracted from the current command.

  Next, the unbalance detection means 17 for detecting the unbalance state of the drum using the third current command 102 and the difference signal 112 will be described.

  In the state where the laundry is rolling, the amplitude of the differential signal including the frequency component corresponding to the rotation of the drum 3 is increased by the catch of the lifter attached to the drum. Further, since the laundry does not stick to the drum, the amplitude of the third current command including a frequency component corresponding to one rotation of the drum is reduced.

  Using these conditions, the unbalance detection means 17 determines imbalance detection according to the flowchart shown in FIG.

  The unbalance detection means 17 starts processing at step 121, and at step 122, the difference between the maximum value and the minimum value of the third current command 102 within one drum rotation cycle time is determined as the third current command fluctuation value. Calculate as Similarly, in step 123, the difference between the maximum value and the minimum value of the difference signal 112 is calculated as the difference signal fluctuation value.

  In step 124, the difference signal fluctuation value calculated in step 123 is compared with a predetermined threshold value. If difference signal fluctuation value> predetermined threshold value, there is a possibility that the laundry is in a rolling state. In other cases, it is determined that the laundry is not rolling, and the process is terminated by moving to step 128.

  In step 125, the third current command fluctuation value calculated in step 122 is compared with a predetermined threshold value. If the third current command fluctuation value <predetermined threshold value, it is determined that the laundry is in a rolling state, and the process is shifted to step 126 to stop the motor. In other cases, it is determined that the laundry is not rolling, and the process is terminated by moving to step 128.

  After determining that the laundry is rolling and stopping the motor, the process proceeds to step 127 to perform the laundry loosening process, and the process ends by proceeding to step 128.

  From this, the unbalance detection means 17 detects the state where the laundry is rolling in the drum, regards this as an unbalanced state, stops the motor, and then performs the laundry loosening step.

  Through the above process, it is possible to realize a highly safe drum-type washing machine that prevents the occurrence of large vibrations and noises in advance by detecting the unbalanced state caused by the laundry being dumped. Become.

  As described above, according to the present embodiment, at the rotational speed at which the centrifugal force acting on the laundry in the drum is greater than the gravity, the dumped laundry is in a state of rolling without sticking to the drum. In this case, it is possible to detect this, and it is possible to prevent the generation of large vibrations and noises in advance, so that a drum-type washing machine with high safety can be realized.

  Further, according to the present embodiment, in the offset adding means, by setting a variable offset value so that the time average of the current command becomes zero, an unnecessary component is extracted from the current command when the fluctuation is extracted from the current command. In addition, it is possible to easily extract a predetermined frequency component from the current command by using a low-pass filter in the frequency component extraction means, so that detection with higher accuracy is possible. It becomes.

It is a block diagram of the program built in the microcomputer 26 in connection with this invention. It is a block diagram of the motor drive device of one Example in connection with this invention. 1 is an external view of a drum type washing machine according to an embodiment of the present invention. 1 is an external view of a drum according to an embodiment of the present invention. It is a wave form diagram in case a laundry is stuck to a drum without unbalance. It is a wave form diagram in case the laundry is biased to the drum. It is a wave form diagram in case the laundry is rolling in the drum. It is a waveform diagram of a current component and frequency components included in the current command. It is a wave form diagram of the 2nd current command outputted from an offset addition means. It is a wave form diagram of the 3rd current command outputted from a frequency component extraction means. It is a wave form diagram of a difference signal output from a difference signal generation means. It is a figure which shows the flow of a process of an unbalance detection means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Speed detection means 12 Motor control command generation means 13 Motor control means 14 Offset addition means 15 Frequency component extraction means 16 Difference signal generation means 17 Unbalance detection means 21 DC conversion inverter circuit 22 Smoothing capacitor 23 DC power supply 24 Motor drive inverter Circuit 25 Motor 26 Microcomputer 27 Magnetic pole position detection means 28 PWM control signal 31 Drum 32 Outer tank 33 Cases 41, 42, 43 Lifter

Claims (3)

  A drum rotatably installed in the outer tub, a motor for driving the drum, a magnetic pole position detecting means for detecting a magnetic pole position of the motor, a rotational speed detecting means for detecting the rotational speed of the motor; Motor control command generating means for outputting a current command for controlling the current of the motor based on the rotational speed detected by the rotational speed detecting means; and a motor based on the magnetic pole position detected by the magnetic pole position detecting means and the current command. Detected by the motor control means for controlling the current, the offset addition means for outputting the second current command by adding a variable offset value to the current command, the number of lifters attached to the drum and the rotation speed detection means A third current command obtained by amplifying the frequency component with a predetermined amplitude gain after extracting a predetermined frequency component determined from the determined rotation speed from the second current command. A frequency component extracting means for outputting, a corrected second current command in which the phase of the signal in the second current command is shifted by a predetermined amount, and a differential signal obtained by a difference between the corrected second current command and the third current command Difference signal generating means to output, third current command fluctuation value obtained from the difference between the maximum value and minimum value of the third current command, and difference signal fluctuation value obtained from the difference between the maximum value and minimum value of the difference signal And a drum-type washing machine comprising: an unbalance detecting means for detecting an unbalanced state of the drum.   The drum type washing machine according to claim 1, wherein the offset adding means sets the variable offset value so that a time average of the current command becomes zero.   The drum type washing machine according to claim 1, wherein the frequency component extraction unit is realized by using a low-pass filter.

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