WO2007080054A1

WO2007080054A1 - A washer/dryer

Info

Publication number: WO2007080054A1
Application number: PCT/EP2006/070138
Authority: WO
Inventors: Kerem Erenay; Latif Tezduyar; Fehmi Sonmezoz; Orhan Diril
Original assignee: Arcelik Anonim Sirketi
Priority date: 2006-01-09
Filing date: 2006-12-22
Publication date: 2007-07-19

Abstract

The present invention relates to a washer/dryer (1) comprising a brushless direct current motor (4), wherein the spinning speed that is formed with respect to unbalanced load during spinning is limited by the field weakening method.

Description

Description A WASHER/DRYER

[0001] The present invention relates to a washer/dryer comprising a brushless direct current motor, wherein the spinning speed is controlled during spinning with respect to unbalanced load.

[0002] In washer/dryers, preferably in washing machines, the laundry defined as load, is washed with water and washing agents in a drum moving rotalably about a shaft axis and they are dried by removing the water contained thereof in the spinning process. During the spinning process, the rotational axis and the center of gravity of the laundry that adhere to the inner wall of the drum do not coincide if the distribution of the laundry is unbalanced. The forces created in this case will result in overstraining of the washing machine resistance and lead to harmful vibrations.

[0003] In conventional applications, in order to prevent the washer/dryers and their vicinity from being damaged, the unbalanced load amount is identified and the problem is tried to be eliminated by applying distribution and spinning phases suitable for the identified unbalanced load. When the unbalanced load is not estimated or identified accurately, then vibration and yield stress can be formed. In some other applications, active dampening methods, for example spinning is carried out by applying active balancing with fluids like water or oil and the formation of problems like vibration and yield is tried to be prevented.

[0004] In state of the art European Patent document no. EP0565157, description is given for a method wherein the torque of the motor first is kept constant, the highest and lowest speeds and the amount and position of the unbalanced load are detected and a component is used for the compensation of an unbalance for the average torque needed for acceleration.

[0005] The object of the present invention is to design a washer/dryer wherein the unbalanced load formed by the unbalanced distribution of the laundry in the spinning phase is controlled by limiting the spinning speeds, thereby enabling a safe operation without causing damage thereto. The washer/dryer designed to fulfill the object of the present invention is explicated in the first claim, whereby its other features are explicated in the respective claims.

[0006] In the present invention, the brushless direct current motor activating the drum is enabled to be driven by a different field weakening angle (aa) thereby creating a different torque value from the brushless direct current motor by making it to detect the motor constant (k) as if it is incrementally decreasing with respect to speed intervals. [0007] The washer/dryer designed to fulfill the object of the present invention is illustrated in the attached figures, where:

[0008] Rgure 1 - is the sideways schematic view of a washer/dryer. [0009] Rgure 2 - is the rear schematic view of a washer/dryer. [0010] Rgure 3 - is the detection graph with respect to time of the three sensors positioned with 60 degree intervals to each other forming two magnets on the shaft with "S" and

"N" poles. [0011] Rgure 4 - is the force variation graph of electromotive force (E) formed on the motor coils according to angular positions. [0012] Rgure 5 - is the force variation graph of electromotive force (E), with applied field weakening thereto, formed on the motor coils according to their angular positions. [0013] The elements illustrated in the figures are numbered as follows:

1. Washer/dryer

2. Drum

3. Control card

4. Motor

5. Tub

6. Body

7. Sensor

8. Shaft

9. Magnet

[0014] The washer/dryers (1), preferably front-loaded washing machines, comprise a body (6), a drum (2) wherein the laundry defined as load (L) is emplaced, providing washing and spinning by rotating around and axis, a tub (5) wherein the drum (2) is emplaced and moves rotatably, a brushless direct current motor (4), a shaft (8) situated on the rear surface center of the drum (2), providing to transfer the drive received from the motor (4) to the drum (2) for activation thereof, one or more magnets (9) situated on the shaft (8), sensors (J) situated just above the magnets (9), the positions thereof as determined by the producer in the figure with phase numbers fixed to the tub (5) consecutively for determining the position of the drum (2), a control card (3) providing to determine the angular velocity of the drum (2) at the angular position ((q) of the sensor (7) with the data gathered from the sensor (7), choosing from among the angular weakening angles (aa), that will be employed in balanced load, unbalanced load and angular velocities, predetermined by the producer and recorded in its memory, the one that corresponds to the balanced load, unbalanced load amount determined by the momentary angular velocity, providing to derive different torque values from the brushless direct current motor (4) by making it to detect as if the motor (4) constant (k) is decreasing incrementally with respect to the velocity intervals, by enabling the phase to be driven with this weakening angle (aa) and enabling the brushless direct current motor (4) to drive the drum (2) at high speeds with the load (L) contained therein without generating noise and yield stress.

[0015] In this embodiment, the drum (2) speeds can be regulated by applying the field weakening method to the brushless direct current motor (4). Consequently, higher velocities can be easily attained.

[0016] Different velocity and torque values can be attained from the motor (4) by driving the motor (4) with field weakening angles (aa) that are different from the phase angle that has to be applied for providing the motor (4) speed determined with the motor (4) constant (k). The degree known as the field weakening angle or current field weakening angle (aa) is the field weakening done with that number of degrees before the passage point that the sensor (7) monitors the magnet (9). The greater the applied current field weakening angle (aa) in the section before, the motor (4) constant (k) behaves as if decreased by that much and the unloaded end velocity of the brushless direct current motor (4) increases by that much.

[0017] In washer/dryers (1), the phases applied are the washing steps wherein the laundry is washed by the washing agents, the rinsing steps wherein rinsing is carried out by water and the spinning step wherein the laundry is dried. These phases are employed by rotating the drum (2) with the laundry contained therein, in different directions, with different velocities. During the operation of the washer/dryers (1), while there is the need for a higher moment during washing, lower moments are sufficient during spinning. This can be observed from voltage and moment equations (equation 1, equation 2) of the motor (4).

[0018] k: motor constant

[0019] w : angular velocity

[0020] R: the motor coil resistance

[0021] I: The current at the motor

[0022] T: moment received from the motor

[0023] Va: the voltage applied to the motor

[0024] Va= kw +RI (equation 1) [0025] T=kl (equation 2)

[0026] During washing, although there is the need for a high moment, the moment requirement during spinning is decreased and the motor (4) constant (k) has to be determined such that it can adapt to all the operating conditions. But the acceleration of the brushless direct current motor (4) velocity is limited by the decrease of its torque. Therefore the field weakening method used provides the motor (4) constant (k) to be detected as if it is incrementally decreasing, depending on the velocity intervals and to simultaneously achieve different current and torque values.

[0027] In the embodiment of the present invention, the field weakening angle (aa) is employed at over the maximum speed that can be attained. Consequently, the field weakening angles (aa) are determined with the desired speed (hi) of the selected washing program and the maximum speed (hm) that can be reached with the existing balanced load and the unbalanced load. The producer determines the field weakening angles (aa) required for balanced loads by experimental dala and determines the field weakening angles (aa) for different speeds of the washer/dryer (1) according to maximum unbalanced load and minimum unbalanced load values. These field weakening angles (aa) are the minimum field weakening angles (aa) that can be used when large unbalanced loads do not exist. The required moments are compensated during the passage of the drum (2) from washing speeds to spinning speeds providing the motor (4) to reach the desired velocity with these field weakening angles (aa). If imbalance increases in a condition wherein the balanced load is assumed to be constant, then the required ascending and holding moments increase and these moments are achieved by large field weakening angles (aa).

[0028] The determination of field weakening angles (aa) is done according to theoretical and empirical dangerous situations. For example, which maximum speed can be attained with a 0 kg. balanced load, x gr unbalanced load is determined by experiments. This maximum load and how much has to be added to the field weakening angle (aa) that enables to reach the desired speed with the unbalanced load that is considered maximum for this load is determined. Consequently the field weakening angle values for the said speed and for lesser speeds are determined. Accordingly, when encountered with a load of 0 kg xl gr (xl>x), speed limitation can be achieved in the washer/dryer (1) even if the imbalance measuring systems used are mistaken and reaching a spinning speed that can cause damage is prevented. Consequently with which field weakening angles (aa) maximum speeds can be reached is determined for balanced and all unbalanced load amounts that can possibly cause problems. [0029] In the embodiment of the present invention, a control card (3) is utilized that provides the field weakening angles (aa) predetermined by the producer enabling maximum speeds that can be reached for balanced and all unbalanced load amounts that can possibly cause problems are used as the field weakening angles (aa) 0° when the desired speed (hi) is smaller than maximum speed (hm) , and when the desired speed (hi) is greater than the maximum speed (hm) to use different field weakening angles (aa) as determined by the producer for these speeds according to the speed acceleration interval (ha) by experimental data.

[0030] When the desired speed (hi) is smaller than the maximum speed (hm) 0 ° is used as the field weakening value (aa), if the desired speed (hi) is greater than the maximum speed (hm) different field weakening angles (aa) are used that are determined by the producer for these speeds according to the speed acceleration interval (ha) by experimental data. That is:

[0031] If (hi<hm), then the field weakening angle = 0 °

[0032] If (hm < hi< (hm+ha)), then the field weakening angle = aa (1)

[0033] If ((hm+ha) < hi< (hm+2ha)), then the field weakening angle = aa (2)

[0034] If ((hm+2ha) < hi< (hm+3ha)), then the field weakening angle = aa (3)

[0035]

[0036] As the field weakening angles (aa) for balanced and unbalanced load combinations are determined, if overlapping field weakening angles (aa) come up, the control card (3) provides application of prioritization and enables the priority to be given to full balanced load and the maximum unbalanced load to be employed in the full balanced load. Consequently, these are the values that increase the unbalanced maximum load and the maximum unbalanced load allowed for this load to the final spinning speed. The control card (3) limits priorly the one with the more dangerous spinning dynamic when there is an overlapping of more than one balanced and unbalanced load combinations.

[0037] In an embodiment of the present invention, the field weakening angle (aa) and the unbalanced load spinning speed limitation are used together with the other unbalanced load algorithms used in the washer/dryers (1). Consequently, when there is an error in one, the other can compensate the error.

[0038] In this embodiment, the producer determines the angular speed (aa) values that enable passing of certain drum (2) angular speed intervals without problems according to the minimum and maximum load amounts the drum (2) can contain with possible unbalanced loads and is provided to operate without generating noise and yield stress in different drum (2) speeds.

[0039] In an embodiment of the present invention, a three phase brushless direct current motor (4) and three sensors (7) (preferably Hall sensors) that are situated on the 360° shaft (8) circumference, with 60° in between, are utilized. Each sensor (7) controls the electrical field between itself and the points that are 60 degrees away in clockwise and counterclockwise directions. Consequently, in each 60 degrees electrical passage from the sensors (7) a value variation is attained. Thus the drum (2) speeds of the washer/ dryer (1) in the spinning steps are determined by the data gathered with the sensors (7). Consequently when the drum (2) speeds are desired to be changed, field weakening is employed and the motor (4) constant (k) is shown differently.

[0040] In another embodiment of the present invention, if there are overlapping field weakening angles (aa) when the field weakening angles (aa) are determined for balanced and unbalanced load combinations, a control card (3) is utilized that applies prioritization and enables the priority to be in the full balanced load and the maximum unbalanced load to be employed in the full balanced load.

[0041] In another embodiment of the present invention, when there is an overlapping of more than one balanced and unbalanced load combinations, a control card (3) is utilized to limit priorly the one with the more dangerous spinning dynamic.

[0042] By way of the embodiment of the present invention, the limitation of the balanced and unbalanced load combinations by the desired spinning speeds that have to be surpassed is provided with the field weakening, current field weakening angle (aa) determination method.

[0043] By way of the embodiment of the present invention, vibration and hence the noise generated during spinning is minimized. Furthermore the possible yield stress is prevented and product malfunction servicing rate can be decreased.

Claims

[0001] A washer/dryer (1) comprising a body (6), a drum (2) wherein the laundry defined as load (L) is emplaced, providing washing and spinning by rotating around and axis, a tub (5) wherein the drum (2) is emplaced to move by rotating a brushless direct current motor (4), a shaft (8) situated on the center of the rear surface of the drum (2), providing to transfer the drive received from the motor (4) to the drum (2) for activation thereof, one or more magnets (9) situated on the shaft (8), sensors (7) situated just above the magnets (9), the positions thereof as determined by the producer in the figure with phase numbers fixed to the tub (5) consecutively for determining the position of the drum (2), and characterized by a control card (3) that provides to determine the angular velocity of the drum (2) at the angular position (q) of the sensor (7) with the data gathered from the sensor (7), choosing from among the angular weakening angles (aa), that will be employed in balanced load, unbalanced load and angular velocities, predetermined by the producer and recorded in its memory, the one that corresponds to the balanced load, unbalanced load amount determined by the momentary angular velocity, providing to derive different torque values from the brushless direct current motor (4) by making it to detect as if the motor (4) constant (k) is decreasing incrementally with respect to the velocity intervals, by enabling the phase to be driven with this weakening angle (aa) and enabling the brushless direct current motor (4) to drive the drum (2) at high speeds with the load (L) contained therein without generating noise and yield stress.

[0002] A washer/dryer (1) as in Claim 1, characterized by a control card (3) that provides the field weakening angles (aa) predetermined by the producer enabling maximum speeds that can be reached for balanced and all unbalanced load amounts that can possibly cause problems, to be used as the field weakening angles (aa) 0° when the desired speed (hi) is smaller than maximum speed (hm) , and when the desired speed (hi) is greater than the maximum speed (hm) to use different field weakening angles (aa) as determined by the producer for these speeds according to the speed acceleration interval (ha) by experimental data.

[0003] A washer/dryer (1) as in Claim 1 to 2, characterized by a control card (3) that provides application of prioritization and enables the priority to be given to full balanced load and the maximum unbalanced load to be employed in the full balanced load , if there are overlapping field weakening angles (aa) while de- termining the field weakening angles (aa) for balanced and unbalanced load combinations. A washer/dryer (1) as in Claim 1 to 2, characterized by a control card (3) that limits with priority the one with the more dangerous spinning dynamic when there is an overlapping of more than one balanced and unbalanced load combinations.