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EP0523371B1 - Machine à laver avec détection de balourd - Google Patents

Machine à laver avec détection de balourd Download PDF

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Publication number
EP0523371B1
EP0523371B1 EP92109786A EP92109786A EP0523371B1 EP 0523371 B1 EP0523371 B1 EP 0523371B1 EP 92109786 A EP92109786 A EP 92109786A EP 92109786 A EP92109786 A EP 92109786A EP 0523371 B1 EP0523371 B1 EP 0523371B1
Authority
EP
European Patent Office
Prior art keywords
signal
tachogenerator
control circuit
strobe
transistor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP92109786A
Other languages
German (de)
English (en)
Other versions
EP0523371A1 (fr
Inventor
Francoise L'hermite
Stephan Ollitrault
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Freescale Semiconducteurs France SAS
Original Assignee
Motorola Semiconducteurs SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Motorola Semiconducteurs SA filed Critical Motorola Semiconducteurs SA
Publication of EP0523371A1 publication Critical patent/EP0523371A1/fr
Application granted granted Critical
Publication of EP0523371B1 publication Critical patent/EP0523371B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F34/00—Details of control systems for washing machines, washer-dryers or laundry dryers
    • D06F34/08—Control circuits or arrangements thereof
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F34/00—Details of control systems for washing machines, washer-dryers or laundry dryers
    • D06F34/14—Arrangements for detecting or measuring specific parameters
    • D06F34/16—Imbalance
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F2103/00—Parameters monitored or detected for the control of domestic laundry washing machines, washer-dryers or laundry dryers
    • D06F2103/26—Imbalance; Noise level
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F2103/00—Parameters monitored or detected for the control of domestic laundry washing machines, washer-dryers or laundry dryers
    • D06F2103/44—Current or voltage
    • D06F2103/46—Current or voltage of the motor driving the drum
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F33/00—Control of operations performed in washing machines or washer-dryers 
    • D06F33/30—Control of washing machines characterised by the purpose or target of the control 
    • D06F33/48—Preventing or reducing imbalance or noise

Definitions

  • This invention relates to the detection of load unbalance in a rotable drum of a washing machine, dryer or like device (herein referred to collectively as "a machine for treating clothes”).
  • EP-A-0 071 308 discloses a control circuit for a machine for treating clothes, the circuit including: control means for providing a desired speed signal for the machine drum; comparing means for comparing the desired speed signal with an actual speed signal to provide an error signal for controlling a switch which is arranged to supply electrical power to an electric motor for driving the machine drum; a tachogenerator for producing a tachogenerator signal representing the speed of the motor at an output thereof; and detection means for detecting the tachogenerator signal representing the speed of the motor and providing said actual speed signal.
  • Fig. 1 shows a known universal motor speed regulation loop for a washing machine with a ramp generator 2 for defining a speed characteristic connected to a first error amplifier 4 input, controlling a pulse generator 6 which switches a triac 8.
  • This triac 8 supplies a universal motor 10 having a tacho generator 12 whose output frequency is proportional to the motor speed and is fed to a pulse integrating frequency to voltage converter 14, whose output, actual speed voltage, is filtered in RC filter 16 and is looped to a second input of error amplifier 4.
  • Load unbalance phenomenon of the load in a washing machine drum appears if such a circuit as an oscillation of actual speed around the desired speed as set by the ramp voltage provided by generator 2.
  • a comparator 18 of an unbalance detector 20 In order to detect such unbalance it is necessary to compare actual with desired speed as set by the ramp voltage in a comparator 18 of an unbalance detector 20, the result of the comparison (E) being compared with a threshold voltage level (V L ) in a comparator 22 in order to reset the ramp voltage, if necessary.
  • the present invention provides a control circuit for a machine for treating clothes, the circuit including: control means for providing a desired speed signal for the machine drum; comparing means for comparing the desired speed signal with an actual speed signal to provide an error signal (E) for controlling a switch which switch is arranged to supply electrical power to an electric motor for driving the machine drum; a tachogenerator for producing a tachogenerator signal representing the speed of the motor at an output thereof; and detection means for detecting the tachogenerator signal representing the speed of the motor and providing said actual speed signal; wherein the detection means includes strobe means responsive to the output of the tachogenerator for generating a strobe signal at a frequency related to the tachogenerator signal frequency, the strobe means being responsive to zero crossing points of the tachogenerator signal in order to generate a strobe signal at or near to a zero crossing point; means for sampling the actual speed signal or the error signal at the frequency of the strobe signal to produce a sampled signal; and
  • the present invention stems from the realization that since the frequency of the load unbalance signal, being the same as the drum frequency, is many times slower (say between 10-100 times slower) than the frequency of the electric motor driving the drum, by sampling the speed signal at or near zero crossing point of the a.c. signal from the tachogenerator (which, having n pairs of poles, is in itself a multiple (n) of the motor frequency), undesirable ripple in the actual speed signal is eliminated and any remaining difference between the tachogenerator signal and desired speed signal will be due to load unbalance.
  • this shows the phenomenon of load unbalance in which a ramp signal which is provided to the motor control for regulating the speed of the motor is denoted V(ramp).
  • V(ramp) the actual speed of the motor
  • V(actual speed) the actual speed of the motor
  • Fig. 3a shows a tachogenerator voltage signal as would be generated by the tachogenerator 12 of Fig. 1. It may be seen that the wave form is sinusoid, with positive going zero crossing points B and negative going zero crossing points C.
  • Fig. 3b shows the actual speed signal which is developed at the output of converter 14 and filter 16 as a ramp wave form again with similar zero crossing points B, C but a maximum error signal E. It may be noted that the characteristics of converter 14 are such that the actual speed signal has a step jump at points B and is quasi-linear between consecutive points B but that at points C the actual speed signal is close to, and slowly varying relative to, the reference signal V(ramp).
  • strobe signals are generated at points C as shown in Fig. 3c in order that the absolute magnitude of the motor speed may be measured at points at which the ripple voltage is not causing any error. It will be appreciated, referring back to Fig. 2 that in the case of load unbalance, the ripple of Fig. 3b will be superimposed on the signal V(actual speed) of Fig. 2. By effecting a comparison at point C, this ripple can be eliminated when comparing the actual speed with the ramp voltage.
  • a frequency to voltage converter 24 is shown. It will be understood that this converter 24 is to be incorporated into the circuit of Fig. 1 and to replace converter 14 of Fig. 1, other parts of the circuit remaining the same.
  • An input port 40 receives an input signal from tachogenerator 12 and this is amplified in an amplifier 42 and applied to the bases of PNP transistors 44, 46.
  • the collector of transistor 44 is coupled to a further PNP transistor 48 which has a resistor R2 in its collector path.
  • the base of transistor 48 and the collector of transistor 46 are coupled to a nodal point 50 to which capacitor C(pump) is coupled.
  • a switch indicated schematically at 52 is coupled via a resistor R1 to nodal point 50.
  • Switch 52 is also coupled to a NPN transistor 54 which is coupled in current mirror configuration to a further NPN transistor 56 which is arranged to supply an output port 60 to which filter 16 is coupled.
  • transistors 44, 46 are switched off and, switch 52 being in the closed position, capacitor C(pump) is charged to voltage V CC .
  • the current pulse thus provided is mirrored through transistor 56 to output port 60 to provide the "actual speed signal", as a series of current pulses which are integrated to a voltage value in RC network 16.
  • switch 52 is switched off whereas transistors 44 and 46 are switched on. Switching on transistor 46 creates a current I1 which discharges C(pump).
  • Transistor 48 is switched on enabling a current I2 to flow through resistor R2 for as long as the voltage at node 50 V(pump) is below V cc . When V(pump) reaches ground, current I2 is terminated by reason of transistor 48 being switched off.
  • the signal voltage developed across resistor R2 is employed as an enabling strobe. It has a short duration (40 microseconds).
  • the enabling strobe is directed along line 70 as shown in Fig. 4 to control a threshold detector 72 which receives as input signals a voltage V L which indicates the minimum acceptable load unbalance voltage, and the output E from error amplifier 18.
  • threshold detector 72 When signal E exceeds threshold V L , comparator 72 when enabled by the strobe signal generates a signal U which is employed to switch or re-start the washing machine drum motor.
  • the biggest problem in washing machines is drum unbalance which creates heavy mechanical stresses.
  • the tendency is to electronically control the unbalance level to save weight and consequently cost, and to increase the overall reliability.
  • the invention described provides a big improvement in this feature while insuring a total integration without any extra outside components. The impact will be a better competitiveness on this market.

Landscapes

  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Control Of Washing Machine And Dryer (AREA)

Claims (8)

  1. Circuit de commande pour machine à traiter le linge, le circuit comportant :
       un moyen de commande (2) servant à fournir un signal de vitesse voulue pour le tambour de la machine ;
       un moyen de comparaison (14) servant à comparer le signal de vitesse voulue avec un signal de vitesse réelle de façon à produire un signal d'erreur (E) destiné à commander un interrupteur (8), lequel interrupteur est conçu pour fournir une puissance électrique à un moteur électrique (10) d'entraînement du tambour de la machine ;
       une génératrice tachymétrique (12) servant à produire, sur une sortie, un signal de génératrice tachymétrique qui représente la vitesse du moteur (10) ; et
       un moyen de détection (14, 24) servant à détecter le signal de la génératrice tachymétrique qui représente la vitesse du moteur et à produire ledit signal de vitesse réelle ;
    caractérisé en ce que le moyen de détection comporte un moyen d'activation par impulsions (44-48) qui répond au signal de sortie de la génératrice tachymétrique en produisant un signal d'impulsions d'activation à une fréquence qui est liée à la fréquence du signal de la génératrice tachymétrique, le moyen d'activation par impulsions répondant à des points de passage par zéro du signal de la génératrice tachymétrique en produisant un signal d'impulsions d'activation en un point de passage par zéro ou en son voisinage ;
       un moyen (72) servant à échantillonner le signal de vitesse réelle ou le signal d'erreur à la fréquence du signal d'impulsions d'activation de façon à produire un signal échantillonné ; et
       un moyen (72) servant à comparer le signal échantillonné avec une valeur de référence (VL) de façon à constater l'existence d'un déséquilibre de charge dans le tambour de la machine.
  2. Circuit de commande selon la revendication 1, où ledit moyen de commande (2) est conçu pour produire une forme d'onde en rampe.
  3. Circuit de commande selon la revendication 1 ou 2, où le moyen de détection (24) comporte un moyen (50-60) servant à charger et, ultérieurement, décharger un condensateur (Cpump) à chaque cycle du signal de la génératrice tachymétrique afin de fournir une série d'impulsions de courant à un moyen de filtrage R-C (16) de façon à constituer le signal de vitesse réelle.
  4. Circuit de commande selon la revendication 3, où le moyen de charge comporte un moyen de commutation (52) qui répond au signal de la génératrice tachymétrique en fournissant un trajet de charge entre une tension d'alimentation électrique et la terre.
  5. Circuit de commande selon la revendication 4, comportant un moyen miroir de courant (54, 56) destiné à faire passer un courant, de même sens et de même intensité que le courant de charge, dans le trajet de charge jusqu'à un accès de sortie (60).
  6. Circuit de commande selon la revendication 4 ou 5, comportant un moyen de commutation à transistor (46) qui est conçu pour être commuté dans l'état conducteur afin de fournir un trajet de courant de décharge pour le condensateur (Cpump).
  7. Circuit de commande selon la revendication 6, où le moyen d'activation par impulsions (44, 48, R2) répond au passage dans l'état conducteur du moyen de commutation à transistor (46) en produisant une impulsion de courant aussi longtemps que la tension présente sur le condensateur (Cpump) reste au-dessus d'un niveau prédéterminé (GND).
  8. Circuit de commande selon la revendication 7, où le moyen d'activation par impulsions comprend un premier transistor (44) qui possède une base commune avec le moyen de commutation à transistor (46), et un deuxième transistor (48) qui possède un trajet de courant principal commun avec le premier transistor et dont la base est couplée au condensateur (Cpump).
EP92109786A 1991-07-11 1992-06-11 Machine à laver avec détection de balourd Expired - Lifetime EP0523371B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9108761A FR2679080B1 (fr) 1991-07-11 1991-07-11 Circuit de commande pour machine a laver permettant la detection d'un desequilibre de charge.
FR9108761 1991-07-11

Publications (2)

Publication Number Publication Date
EP0523371A1 EP0523371A1 (fr) 1993-01-20
EP0523371B1 true EP0523371B1 (fr) 1995-12-20

Family

ID=9415003

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92109786A Expired - Lifetime EP0523371B1 (fr) 1991-07-11 1992-06-11 Machine à laver avec détection de balourd

Country Status (3)

Country Link
EP (1) EP0523371B1 (fr)
DE (1) DE69206905T2 (fr)
FR (1) FR2679080B1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20000007275A (ko) * 1998-07-02 2000-02-07 윤종용 드럼세탁기의 언밸런스 검출방법
US6381791B1 (en) 1998-11-20 2002-05-07 Emerson Electric Co. Washing machine tub speed control method and apparatus
US6282965B1 (en) 1998-11-20 2001-09-04 Emerson Electric Co. Method and apparatus for detecting washing machine tub imbalance
KR20070048918A (ko) * 2005-11-07 2007-05-10 삼성전자주식회사 세탁기 및 그 언밸런스 검출방법

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1038355B (it) * 1975-05-22 1979-11-20 Ire Spa Procedimento e macchina automatica per lavare e centrifugare la biancheria
FR2489384A1 (fr) * 1980-09-02 1982-03-05 Esswein Sa Dispositif de suppression de balourd dans une centrifugeuse et machine, lave-linge notamment, comportant un tel dispositif
GB2102985A (en) * 1981-07-31 1983-02-09 Philips Electronic Associated Drum speed control system for a washing machine
US5070565A (en) * 1989-04-17 1991-12-10 Emerson Electric Co. Unbalanced load detection system and method for a household appliance

Also Published As

Publication number Publication date
DE69206905D1 (de) 1996-02-01
FR2679080B1 (fr) 1994-03-11
DE69206905T2 (de) 1996-07-11
HK1000805A1 (en) 1998-05-01
FR2679080A1 (fr) 1993-01-15
EP0523371A1 (fr) 1993-01-20

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