DE102014209112A1 - Valve device for a household appliance, household appliance and corresponding method - Google Patents

Abstract

The invention relates to a valve device (6) for a domestic appliance (1), comprising a shut-off element (27) for controlling a flow of a fluid in a line (5) of the domestic appliance (1), a drive element (20) for moving the shut-off element (27 ) from an open position, in which the line (5) is opened, in a closed position, in which the line (5) is shut off by the shut-off element (27), depending on a current flow (I) through the drive element (20) the drive element (20) is electrically coupled to a DC voltage source (12), at least one electrically coupled to the drive element (20) switching element (22) for controlling the current flow (I) by the drive element (20), and a control device (25) for Control of the at least one switching element (22), wherein the control device (25) is designed to control the current flow (I) by the drive element (20) a series of drive pulses (30) to the a switching element (22), wherein the valve device (6) has means for detecting a current voltage value (V) of a DC voltage (VZK) provided by the DC voltage source (12) and the control device (25) is designed to have a pulse length (w ) to adjust the drive pulses (30) in response to the current voltage value (V), and wherein the control means (25) is adapted to provide a predetermined pull-in current (IA) for moving the shut-off element (27) from the closed position to the open position and the pulse length (W) the drive pulses (30) for providing the pull-in current (IA) depending on the current voltage value (V) to set.

Description

The invention relates to a valve device for a household appliance, with a shut-off for controlling a flow of a fluid in a line of the household appliance, a drive element for moving the shut-off of an open position in which the line is open, in a closed position, in which the line through the shut-off is shut off, depending on a current flow through the drive element, wherein the drive element is electrically coupled to a DC voltage source, an electrically coupled to the drive element switching element for controlling the flow of current through the drive element, and a control device for driving the switching element, wherein the control means is designed to emit a sequence of drive pulses to the switching element for controlling the current flow through the drive element, wherein the valve means comprises means for detecting a current voltage value of a DC voltage source e provided DC voltage and the control device is adapted to set a pulse length of the drive pulses depending on the current voltage value. The invention also relates to a domestic appliance with such a valve device and a method for controlling a flow of a fluid in a line of a household appliance.

The interest is directed in the present case, in particular, to a valve device which serves to shut off or control a flow of a fluid in a line of a domestic appliance. Such a valve device can be used for example for a washing machine or a dishwasher. Such valve devices for household appliances are already known from the prior art in a variety of configurations. These valve devices may be formed, for example, as a solenoid valve. Such a solenoid valve comprises a shut-off element in the form of a valve piston and a drive element in the form of an electromagnet. With the drive element, the shut-off element can be moved from a closed position in which the line is shut off by the shut-off element and the fluid can not flow through the line into an open position in which the line is open and the fluid can flow through the line.

The electromagnet or its coil is usually coupled in the prior art directly to a mains connection of the household appliance and thus operated with the mains voltage. The solenoid valves are operated in this case with an AC voltage. As a switching element for controlling the current flow through the coil, a triac is used, which is controlled by means of a corresponding microcontroller. A disadvantage of using a triac is the fact that the control terminal (gate) of the triac must be at the reference potential of the supply network or at the neutral potential (N). This in turn means that the microcontroller is also at this reference potential. In modern home appliances then a galvanic isolation between the microcontroller and other control devices must be ensured, which have a different electrical reference potential. For example, a motor control device for driving a three-phase brushless DC motor or a synchronous machine must preferably be at a reference potential, which is different from the said neutral potential of the supply network. In order to allow mutual communication between the various control devices, therefore, for example, optocouplers are used, which provide the required galvanic isolation.

A remedy here creates the use of a DC voltage source for driving the solenoid valve. Usually used solenoid valves, which are designed for operation with an AC voltage can also be operated with a DC voltage, as long as it is within a certain range. In principle, it is known to control solenoid valves by means of a pulse width modulated voltage. This is for example in the US 2010/0175001 A1 mentioned.

If a DC voltage source is used to supply a valve device, however, the problem arises that the DC voltage provided by the DC voltage source can break down when the energy is delivered to electrical consumers. This is the case in particular when a capacitor is used as the DC voltage source and the energy for the coil or other load is taken from the capacitor. This removal of electrical energy then causes a voltage drop across the capacitor, which then needs to be recharged. The charging of the capacitor is in turn dependent on the current phase position of the mains voltage. This problem is exacerbated even if additional consumers are supplied with the electrical energy from the DC voltage source. If the transistor is now driven with drive pulses of predetermined and constant pulse length, then it may happen that the electrical energy or power delivered to the coil is altogether insufficient to hold the shut-off element in the open position. Optionally, a reliable operation of the household appliance is then not possible.

In this context, the describes US 4,838,037 A a solenoid valve for a refrigerant circuit. In this case, the flow of the refrigerant in the refrigerant circuit with the solenoid valve in response to the signal of a temperature sensor can be adjusted. The solenoid valve is controlled in this case by means of pulse width modulation to adjust the flow of refrigerant through the valve. In addition, it is provided to monitor the electrical voltage provided by a voltage source for supplying the solenoid valve. In response to the detected voltage of the voltage source, the duty cycle of the pulse width modulation is adjusted to allow reliable operation of the solenoid valve.

It is an object of the invention to provide a solution, as in a valve device of the type mentioned a reliable and efficient operation can be made possible.

This object is achieved by a valve device, by a household appliance and by a method with the features according to the respective independent claims. Advantageous embodiments of the invention are the subject of the dependent claims, the description and the figures.

A valve device according to the invention for a household appliance comprises a shut-off element for controlling a flow of a fluid in a line of the household appliance, a drive element for moving the shut-off element from an open position, in which the line is open, into a closed position, in which the line is shut off by the shut-off element is dependent on a current flow through the drive element, wherein the drive element is electrically coupled to a DC voltage source, at least one electrically coupled to the drive element switching element for controlling the flow of current through the drive element, and a control device for driving the at least one switching element, wherein the control means is designed to deliver a sequence of drive pulses to the at least one switching element for controlling the current flow through the drive element, wherein the valve device means for detecting a current voltage value it has DC voltage provided by the DC voltage source and the control device is designed to set a pulse length of the drive pulses as a function of the current voltage value. In addition, the control device is designed to provide a predetermined attraction current for moving the shutoff element from the closed position into the open position and to set the pulse length of the drive pulses for providing the starting current as a function of the current voltage value.

The drive element is preferably designed as an electromagnet. This electromagnet may comprise a coil through which the electric current flows. By determining the pulse length of the current drive pulses and thus the pull-in current as a function of the current voltage level of the DC voltage is achieved that the pulse length of the drive pulses is always adjusted to the current voltage value. Thus, the drive element can be operated independently of the voltage provided with the DC voltage source with a constant starting current. Thus, the pulse length of the drive pulses at a lower voltage value can be set greater than at a higher voltage value in order to always be able to ensure that a sufficient power is delivered to the drive element. Due to the constant starting current, the shut-off element can be safely and reliably moved from the closed position into the open position. This can be guaranteed that the valve device can be opened independently of the voltage value of the DC voltage source and thus the flow of the fluid can be made possible. Overall, thus a reliable and reliable operation of the valve device is made possible.

In the present case, a domestic appliance is understood to mean, in particular, a water-conducting appliance which is used for household management. In particular, the household appliance is a device for the care of laundry items, such as a washing machine, a washer-dryer or a tumble dryer. The household appliance can also be a dishwasher. In particular, a liquid flow in at least one line of the household appliance can be shut off or controlled with the valve device. For example, the valve device can be used in a water inlet of the household appliance.

As a switching element, in particular a semiconductor switch can be used, whose control terminal is coupled to the control device. As a semiconductor switch, for example, a PNP bipolar transistor and / or an NPN bipolar transistor and / or an N-MOSFET and / or a P-MOSFET and / or an IGBT can be used.

In an embodiment, it may be provided that the control device actuates the switching element using a pulse width modulation. Then, the controller may set a current duty ratio of the drive pulses depending on the current voltage value. The drive pulses can therefore be a act periodic sequence of pulses, in which the ratio of the pulse duration to the period is set in dependence on the current voltage value. This has the advantage on the one hand that the sequence of drive pulses can thus be synchronized with the mains voltage without much effort; On the other hand, such a pulse width modulation can be implemented with a periodic sequence of pulses without much effort, since the frequency of the drive pulses remains basically constant and only the current duty cycle needs to be adjusted depending on the current voltage value.

It proves to be particularly advantageous if the control device is designed to provide a predetermined holding current for holding the shut-off element in the open position and to set the pulse length of the drive pulses for providing the holding current as a function of the current voltage value. To open the valve device, the drive element can first be supplied with the starting current for a predetermined period of time. When the shut-off element is in the open position, the drive element can be operated with the holding current. The holding current can be kept constant by adjusting the pulse length of the drive pulses. The holding current may have a lower amplitude or a lower effective value compared to the starting current. Thus, a reliable and energy-saving operation of the valve device can be made possible.

It proves to be particularly advantageous if the DC voltage source is an intermediate circuit capacitor, which is coupled to an output of a rectifier, in particular a full-bridge rectifier, which is designed to rectify a mains voltage. The rectifier is in particular coupled, on the one hand, to mains connections of the household appliance and, on the other hand, to the intermediate circuit capacitor, so that the rectified rectifier voltage is delivered to the intermediate circuit capacitor and then smoothed with the intermediate circuit capacitor. At the DC link capacitor is thus a rectified and smoothed mains voltage (RMS value), which can be used for the control of the valve device. This embodiment has the advantage that an already present in today's household appliances already existing electrical DC link can be used to move the shut-off in the open position or to hold in this open position. It is therefore unnecessary to use separate DC sources with the associated disadvantages.

In addition, an inverter, which is designed to provide a supply voltage for an electric drive motor of the domestic appliance from the DC voltage, is additionally coupled to the same DC voltage source, in particular to the named DC link capacitor. So it is specifically used the DC voltage source, which otherwise serves to supply the drive motor. In this context, it may in particular be provided that the drive motor is a multiphase-in particular three-phase brushless DC motor (BLDC) or a synchronous machine, so that the inverter generates a plurality of alternating voltages from the DC voltage for the operation of the drive motor. Preferably, this drive motor is used to drive a laundry drum of the household appliance.

It is preferably the relationship that the smaller the DC voltage at the DC voltage source, the greater the pulse length of the drive pulses is set. In other words, at a lower voltage value of the DC voltage, the control device can set a larger pulse length of the drive pulses than at a higher voltage value, so that the pulse length is inversely proportional to the DC voltage at the DC voltage source. By such an approach can always be ensured that a sufficient electric current flows through the drive element on average, which ensures safe operation of the valve device.

In order to keep constant the mean value of the electric current through the drive element and thus the power delivered to the drive element, the control means may adjust the pulse length of the drive pulses inversely proportional to the square of the voltage value of the DC voltage. An unwanted adjustment of the shutoff in the operation of the household appliance can thus be reliably prevented.

In the control device, for example, a lookup table can be stored, which indicates the dependence of the pulse length of the DC voltage of the DC voltage source. The controller may then adjust the current pulse length using the lookup table. The setting of the pulse length depending on the current voltage value can thus be realized without much computing power.

In addition to said switching element (hereinafter referred to as the first switching element), the valve device may also comprise at least one further switching element (hereinafter referred to as second and third switching element) which is coupled to the drive element and in particular electrically connected in series with the first switching element and the drive element. The control device can be designed so that at least during the drive pulses of the first switching element, the second switching element is opened, so that this second switching element is driven with drive pulses, which have at least the same pulse length as the drive pulses of the first switching element. The drive pulses of the second switching element thus overlap with the drive pulses of the first switching element. The use of the second switching element has advantages in terms of reliability: In case of failure of one of the switching elements can be prevented with the other switching element, that the drive element - in particular a coil - is acted upon by a DC voltage. If a defect or an error of one of the switching elements is detected by the control device, a corresponding warning signal can be output.

It can also be provided that a current phase position of the mains voltage is detected by the control device and the sequence of the drive pulses is generated as a function of the phase of the mains voltage. In this way, the sequence of drive pulses can be synchronized with the mains voltage and, for example, it is possible to generate the drive pulses when the DC voltage source is fully charged. Excessive discharge of the DC voltage source can thus be reliably prevented.

An inventive household appliance, in particular for the care of laundry items, comprises a line and a valve device according to the invention for controlling a flow of a fluid in the line.

An inventive method is used to control a flow of a fluid in a line of a household appliance by means of a shut-off, which is dependent on a current flow through a drive element from an open position in which the line is opened, moved to a closed position in which the line through the Shut-off is shut off, wherein the drive element is acted upon by a DC voltage of a DC voltage source and the current flow is controlled by the drive element by means of at least one switching element which is driven by a control device with a series of drive pulses. In addition, a current voltage value of the DC voltage is detected and a pulse length of the drive pulses is set by the control device as a function of the current voltage value. In addition, a predetermined attraction current for moving the shutoff element from the closed position to the open position is provided with the control device, and the pulse length of the drive pulses for providing a starting current is set as a function of the current voltage value.

The preferred embodiments presented with reference to the valve device according to the invention and their advantages apply correspondingly to the domestic appliance according to the invention and to the method according to the invention.

Further features of the invention will become apparent from the claims, the figures and the description of the figures. All the features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively indicated combination but also in other combinations or alone.

The invention will now be described with reference to a preferred embodiment and with reference to the accompanying drawings.

Show it:

1 a schematic representation of a household appliance according to an embodiment of the invention;

2 a schematic representation of a circuit arrangement with a valve device according to an embodiment of the invention; and

3 a time course of a current flow in a drive element of the valve device.

An in 1 illustrated household appliance 1 is for example a washing machine. The household appliance 1 includes a laundry drum 2 for receiving items of laundry, which in a housing 3 of the household appliance 1 - And in a non-illustrated tub - around a horizontal axis of rotation 4 is rotatably mounted. The laundry items can pass through an opening in the laundry drum 2 are introduced, which can be closed by means of a door. To drive the laundry drum 2 includes the household appliance 1 an electric drive motor 7 , The user can use an operating device 8th the desired operating program of the household appliance 1 select and activate the operating process.

The household appliance 1 also includes one or more lines 5 for guiding a fluid, in particular water. In the present example is only one line 5 shown.

To the flow of fluid in the pipe 5 to be able to control includes the household appliance 1 a valve device 6 , The valve device 6 can be designed in particular as a solenoid valve. The valve device 6 has a shut-off element 27 . which by means of a drive element 20 can be moved on. The drive element 20 is designed in particular as a coil or as an electromagnet, which can be traversed by an electric current. With the drive element 20 can the shut-off 27 be moved from an open position to a closed position. The shut-off element 27 may be formed of a soft magnetic material. In addition, the shut-off 27 be designed as a valve piston or as a membrane which is held by a spring in the closed position. The valve device 6 Optionally has another shut-off element 27 ' , which by means of a drive element 20 ' can be moved on.

A circuit arrangement, as in 2 is shown, is part of the household appliance 1 and includes the valve device 6 , The household appliance 1 has power connections 9 . 10 which are at electrical potentials L, N of the supply network. Between the power connections 9 . 10 a mains voltage U _{N is} provided, which is an AC voltage. The AC voltage U _N is by means of a rectifier 11 rectified, which is formed in the embodiment as a full-bridge rectifier with four diodes. The output side is the rectifier 11 with a DC link capacitor 12 coupled, which smoothes the rectified voltage. An intermediate circuit _{DC voltage} V _ZK is located between a _DC link node 13 on the one hand and a reference potential 14 on the other hand. The reference potential 14 is an electric potential different from the neutral potential N. The DC link capacitor 12 represents a DC voltage source in the context of the present invention.

In the embodiment, the drive motor 7 a three-phase synchronous machine or a brushless DC motor (BLDC) with permanent magnets. Alternating voltages for the stator winding are by means of an inverter 15 provided comprising a multi-transistor inverter and the DC link node 13 is coupled. The AC voltages for the drive motor 7 So are provided from the intermediate circuit DC voltage V _ZK or the inverter 15 is with electrical energy from the DC link capacitor 12 provided. The inverter 15 is doing by an engine control unit 16 driven. This engine control unit 16 lies at the reference potential 14 and is supplied with a supply voltage, which by means of a DC-DC converter 17 , For example, a switching power supply, is provided from the intermediate circuit DC voltage V _ZK . This supply voltage can be 3.3 V or 5 V, for example.

The valve device 6 in this case comprises a first solenoid valve 28 and a second solenoid valve 28 ' , wherein the second solenoid valve 28 ' is optionally provided. Thus, the flow of fluid in a first conduit with the first solenoid valve 28 and the flow of the fluid in a second conduit to the second solenoid valve 28 ' to be controlled. Alternatively, the fluid flow in the conduit 5 at two different locations with the first and second solenoid valves 28 . 28 ' to be controlled. The drive element 20 the respective solenoid valves 28 . 28 ' is with a node 19 connected, on which the same electrical potential as on the DC link 13 is applied. The drive element 20 of the first solenoid valve 28 on the other hand, is via a node 21 and via a series connection of a first and a second switching element 22 . 23 with the reference potential 14 coupled. So it is a series circuit of the drive element 20 and the switching elements 22 . 23 in front. A freewheeling diode 24 connects the node 21 with the node 19 and thus allows a current flow through the drive element 20 when the switching elements 22 . 23 lock. The second solenoid valve 28 ' is electrically connected to a third switching element 32 connected.

In the embodiment, the switching elements 22 . 23 . 32 designed as NPN bipolar transistors. The collector of the first switching element 22 is with the node 21 connected; the emitter of the switching element 22 is connected to the collector of the second switching element 23 over the node 18 connected. The emitter of the second switching element 23 is with the reference potential 14 connected and thus lies on the reference potential 14 , The emitter of the third switching element 32 is with the node 18 connected and the collector of the third switching element 32 is with the node 33 connected. The knot 33 on the one hand with the drive element 20 of the second solenoid valve 28 ' and on the other hand with another freewheeling diodes 24 electrically connected.

For controlling the switching elements 22 . 23 . 32 is a control device 25 provided in the form of a microcontroller, which with the base terminals of the switching elements 22 . 23 . 32 is connected and also on the reference potential 14 lies. A supply voltage (for example 3.3V or 5V) for the controller 25 is by means of a DC-DC converter 26 , For example, a switching power supply generated. Optionally, the control device 25 also integral with the engine control unit 16 be formed, so that the control device 25 and the engine control unit 16 are formed by a single control device, in particular a microcontroller.

A current flow I through the drive element 20 causes the shut-off 27 is moved from the closed position to the open position. To the current position of the shut-off element 27 can check in the solenoid valves 28 . 28 ' a detection device may be provided which is connected to the control device 25 is coupled. There is also a knot 29 between the emitter of the first switching element 22 and the collector of the second switching element 23 with the control device 25 coupled, so that also a current flow through the switching elements 22 . 23 . 32 and thus the proper functioning of the switching elements 22 . 23 . 32 can be checked. Between the controller 25 and the switching elements 22 . 23 . 32 in each case a coupling capacitor C1, C2, C3 is connected. By the coupling capacitors C1, C2, C3 can be prevented that the switching elements 22 . 23 . 32 be activated continuously in case of malfunction.

The switching element 22 is through the control device 25 with a sequence of drive pulses 30 controlled using a pulse width modulation. The second switching element 23 serves as a safety switching element and can be independent of the switching element 22 be controlled. To control the drive element 20 can release the safety switch element 23 synchronous to the first switching element 22 be driven with a same sequence of drive pulses or alternatively with longer pulses, so that the second switching element 23 at least during the entire duration of the drive pulses 30 of the first switching element 22 is open. Alternatively, the second switching element 23 also be switched through constantly. In the latter case, the coupling capacitor C2 can be omitted. To control the drive element 20 to prevent and thus the switching of the solenoid valve 28 can prevent the safety switching element 23 be locked.

The activation of the safety switching element preferably takes place independently of the switching element 22 by one in the control device 25 implemented safety circuit or a software function. This can be independent of the function commands for the shut-off 27 a safety function can be realized.

The optional third switching element 32 can be synchronous with the first switching element 22 with the same sequence of drive pulses 30 be controlled. Alternatively, the third switching element 32 with longer or shorter pulses independent of the first switching element 22 be controlled to the shut-off 28 ' to operate separately. In the illustrated circuit, the second switching element is subject 32 but also the release by the same safety switch element 23 ,

The valve device 6 also includes means for detecting the current voltage value of the intermediate circuit _DC voltage V _ZK . The current voltage value is thereby by the control device 25 detected, which for this purpose, for example, a separate measuring input (not shown) may have, which - for example, via a voltage divider or another DC-DC converter - with the DC link 13 connected is. Additionally or alternatively, the detection of the voltage value of the DC link voltage V _ZK via a supply input 31 take place, over which the control device 25 the above supply voltage is supplied.

It is provided that the duty cycle of the drive pulses 30 and thus the temporal pulse length of the drive pulses 30 is set as a function of the current voltage value of the intermediate circuit _DC voltage V _ZK . For this purpose, the control device detects 25 continuously or continuously the respective instantaneous voltage value of the intermediate circuit DC voltage V _ZK and continuously controls the pulse length of the drive pulses 30 , which continuously to the first switching element 22 are discharged to the shut-off 27 during operation of the household appliance 1 keep continuously in the open position. It is the to the drive element 20 output electric power kept constant over time by the pulse length of the drive pulses 30 is adjusted depending on the current voltage value of the intermediate circuit _DC voltage V _ZK or adapted to the current voltage value. This adaptation looks such that the pulse length of the drive pulses 30 is inversely proportional to the square of the DC link _voltage V _ZK .

In 3 is the course of the current flow I, by the drive element 20 flows, as a function of the time t shown. At a time T1, the current flow I is increased until it reaches the starting current I _A at a time T2. The attraction current I _A is used to move the shut-off element 27 from the closed position to the open position. The starting current I _A is up to a time T3 on the drive element 20 created. After opening the pipe 5 the current flow I through the drive element 20 reduces until it reaches a holding current I _H at a time T4. In that the drive element 20 initially operated with the starting current I _A , it can be ensured that the solenoid valve 28 . 28 ' Reliably opens. When the valve is opened, the electric current I can be reduced to the holding current I _H. This can be prevented that the drive element 20 is overheated during operation. Instead of the current flow I can also be an electrical voltage applied to the drive element 20 is adjusted accordingly.

The values for the starting current I _A and the holding current I _H and the times T1, T2, T3 and T4 are for the respective embodiment of the solenoid valve 28 . 28 ' predetermined. In this case, the starting current I _A and the holding current I _H are kept constant in the predetermined time ranges by the pulse length of the drive pulses 30 is set depending on the current voltage value of the intermediate circuit _DC voltage V _ZK . Alternatively to the illustration according to 3 It can also be provided that the attraction current I _A at predetermined times several times in succession in the drive element 20 is impressed. In addition, the time at which the attraction current I _A in the drive element 20 is changed, be changed.

In that the drive element 20 is operated only for a predetermined period of time with the attraction current I _A , a solenoid valve 28 . 28 ' used that compared to commonly used solenoid valves 28 . 28 ' designed for lower electrical power. In this way, material and costs can be saved. In addition, a reliable and energy-efficient operation of the valve device 6 be guaranteed. Furthermore, solenoid valves 28 . 28 ' used, which are designed for operation with an AC voltage.

LIST OF REFERENCE NUMBERS

1

 household appliance

2

 washing drum

3

 casing

4

 axis of rotation

5

 management

6

 valve means

7

 electric drive motor

8th

 operating device

9, 10

 mains connection

11

 rectifier

12

 Link capacitor

13

 Intermediate circuit node

14

 reference potential

15

 inverter

16

 Engine control unit

17

 DC converter

18

 node

19

 node

20, 20 '

 driving element

21

 node

22, 23

 switching element

24

 Freewheeling diode

25

 control device

26

 DC converter

27, 27 '

 shut-off

28, 28 '

 magnetic valve

29

 node

30

 drive pulses

31

 supply input

32

 switching element

33

 node

C1, C2, C3

 capacitor

I

 current flow

I _A

 Starting current

I _H

 holding current

L

 electrical potential

N

 electrical potential

T1, T2, T3, T4

 time

t

 Time

U _N

 mains voltage

V _ZK

 Intermediate circuit voltage

w

 pulse length

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 2010/0175001 A1 [0004]
• US 4838037 A [0006]

Claims (11)

Valve device ( 6 ) for a household appliance ( 1 ), with: - a shut-off element ( 27 ) for controlling a flow of a fluid in a conduit ( 5 ) of the household appliance ( 1 ), - a drive element ( 20 ) for moving the shut-off element ( 27 ) from an open position in which the line ( 5 ) is opened, in a closed position, in which the line ( 5 ) through the shut-off element ( 27 ) is shut off, depending on a current flow (I) through the drive element ( 20 ), wherein the drive element ( 20 ) with a DC voltage source ( 12 ) is electrically coupled, - at least one with the drive element ( 20 ) electrically coupled switching element ( 22 ) for controlling the current flow (I) by the drive element ( 20 ), and - a control device ( 25 ) for controlling the at least one switching element ( 22 . 23 ), wherein the control device ( 25 ) is designed to control the current flow (I) by the drive element ( 20 ) a sequence of drive pulses ( 30 ) to the at least one switching element ( 22 ), wherein - the valve device ( 6 ) Means for detecting a current voltage value (V) by the DC voltage source ( 12 ) provided DC voltage (V _ZK ) and the control device ( 25 ) is adapted to a pulse length (w) of the drive pulses ( 30 ) depending on the current voltage value (V), characterized in that the control device ( 25 ) is adapted to a predetermined attraction current (I _A ) for moving the shut-off element ( 27 ) from the closed position to the open position and the pulse length (w) of the drive pulses ( 30 ) for providing the pull-in current (I _A ) depending on the current voltage value (V). Valve device ( 6 ) according to claim 1, characterized in that the control device ( 25 ) is adapted to a predetermined holding current (I _H ) for holding the shut-off ( 27 ) in the open position and the pulse length (w) of the drive pulses ( 30 ) for providing the holding current (I _H ) depending on the current voltage value (V). Valve device ( 6 ) according to claim 1 or 2, characterized in that the DC voltage source ( 12 ) is a link capacitor, which is connected to an output of a rectifier ( 11 ), in particular a full-bridge rectifier, which is designed to rectify a line voltage (U _N ). Valve device ( 6 ) according to one of the preceding claims, characterized in that with the same DC voltage source ( 12 ) an inverter ( 15 ), which is used to provide a supply voltage for an electric drive motor ( 7 ) of the household appliance ( 1 ) is formed from the DC voltage (V _ZK ). Valve device ( 6 ) according to one of the preceding claims, characterized in that the control device ( 25 ) is designed, at a lower voltage value (V) of the DC voltage (V _ZK ) a larger pulse length (w) of the drive pulses ( 30 ) than at a higher voltage value (V). Valve device ( 6 ) according to one of the preceding claims, characterized in that the control device ( 25 ) is adapted to adjust the pulse length (w) in inverse proportion to the square of the voltage value (V). Valve device ( 6 ) according to one of the preceding claims, characterized in that in the control device ( 25 ) a look-up table is stored, which indicates the dependence of the pulse length (w) on the DC voltage (V _ZK ), wherein the control device ( 25 ) is adapted to adjust the pulse length (w) using the lookup table. Valve device ( 6 ) according to one of the preceding claims, characterized in that in addition to the at least one switching element ( 22 ) at least one further switching element ( 23 ) with the drive element ( 20 ) and the control device ( 25 ) is designed, at least during the drive pulses ( 30 ) of the at least one switching element ( 22 ) the at least one further switching element ( 23 ) to open. Valve device ( 6 ) according to one of the preceding claims, characterized in that the control device ( 25 ) is adapted to detect a current phase position of a mains voltage (U _N ) and the sequence of the drive pulses ( 30 ) depending on the phase of the mains voltage (U _N ). Household appliance ( 1 ), in particular for the care of laundry, with a line ( 5 ) and with a valve device ( 6 ) according to any one of the preceding claims. Method for controlling a flow of a fluid in a conduit ( 5 ) of a household appliance ( 1 ) by means of a shut-off element ( 27 ), which depends on a current flow (I) by a drive element ( 20 ) from an open position in which the line ( 5 ) is moved, is moved to a closed position in which the line ( 5 ) through the shut-off element ( 27 ) is shut off, the Drive element ( 20 ) with a DC voltage (V _ZK ) of a DC voltage source ( 12 ) and the current flow (I) through the drive element ( 20 ) by means of at least one switching element ( 22 ) which is controlled by means of a control device ( 25 ) with a sequence of drive pulses ( 30 ) is controlled, wherein a current voltage value (V) of the DC voltage (V _ZK ) is detected and a pulse length (w) of the drive pulses ( 30 ) by the control device ( 25 ) depending on the current voltage value (V) is characterized in that the control device ( 25 ) a predetermined attraction current (I _A ) for moving the shut-off element ( 27 ) is provided from the closed position to the open position and the pulse length (w) of the drive pulses ( 30 ) is set to provide the starting current (I _A ) depending on the current voltage value (V).

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