EP1947391A2 - Device for switching on and off a hotplate and method for determining incorrect operation of a hotplate - Google Patents

Abstract

A clocking relay (12) performs clocking operation of a heating device (10) in a cooking area. A measurement device (18) determines current through the relay coil of the clocking relay. A control and evaluation device (14) drives the clocking relay, and assesses faulty operation of the cook top based on the measured current through the relay coil. An independent claim is also included for a method of assessing faulty operation of cook top.

Description

The present invention relates to a device for switching a hob with at least one hotplate according to the preamble of claim 1 or 3 and a method for assessing a faulty operation of a hob with at least one hotplate according to the preamble of claim 6 and 7 respectively.

Usually, the electric heaters of cooking zones of a hob are each connected via a clock relay to operate the heaters with a desired heat output in the cycle mode. Further, it is common to use a phase separation relay for simultaneously disconnecting a plurality of heaters from the operating voltage.

In order to avoid an error in such Relaisansteuerungen by gluing the relay contacts or in the control, often a second relay contact is installed by an additional relay for safety. The problem with this method is that an error in the control of the relay or sticking of the relay contact can not be recognized in part, since they do not necessarily have to lead immediately to a noticeable malfunction. If then another error occurs, there is a malfunction that may not be able to be turned off.

The invention has for its object to provide a device for switching a hob with at least one cooking point that can reliably assess a faulty operation of the hob. It is a further object of the present invention to provide a method for safely assessing erroneous operation of a cooktop having at least one cooking location.

The above objects are achieved by a device having the features of claim 1 or 3 or by a method having the features of claim 6 or 7. Advantageous embodiments and modifications of the invention are the subject of the dependent claims.

According to a first aspect of the invention, the device for switching a hob with at least one hotplate on a clock relay for clocking the operation of a heater of a cooking place and a control device for driving the clock relay. The apparatus is further provided with relay coil current measuring means for measuring the current through a relay coil of the clock relay and evaluation means for judging erroneous operation of the hob on the basis of the current measured by the relay coil measuring means through the relay coil of the clock relay. With such a device, for judging erroneous operation of a cooktop having at least one hotplate, a current through a relay coil of the clock relay can be measured, and erroneous operation of the cooktop can be judged based on the measured current through the relay coil of the clock relay.

This method is a particularly simple and therefore cost-effective way to assess a faulty operation of a hob with at least one cooking point. As a possibility of erroneous operation of the hob is here in particular to call a faulty control of the clock relay.

The relay coil current measuring device is preferably provided in a drive branch of the clock relay.

A clock relay is understood to mean a mechanical relay, an electronic relay and an electronic circuit breaker.

According to a second aspect of the invention, the apparatus for switching a hob with at least one cooking point comprises a clock relay for clocking the operation of a heater of a cooking place, a phase separation relay for separating the heating of the cooking place from the power supply and a control means for driving the clock Relay and the phase separation relay on. The device is further characterized by a load current measuring device for measuring the current through the heating means of the cooking station and an evaluation device for judging erroneous operation of the hob on the basis of the current measured by the load current measuring device by the heater. With such a device, to judge erroneous operation of the cooktop, a current through the cooktop heater can be measured, and erroneous operation of the cooktop can be judged based on the measured current through the heater.

As an alternative to measuring the current, the voltage applied to the load can be measured.

In addition to the detection of a faulty control of the clock relay as in the first aspect also errors in the clock relay itself (e.g., bonded relay contacts) can be detected with this method. Furthermore, with this method it is also possible to detect which load is being operated on the individual branches, so that the electronics can independently adjust to different load conditions and prevent an overload of individual phases. In addition, it is possible to ensure a maximum current load.

The load current measuring device is preferably provided in an operating current line of the heating device.

If this method is applied to a cooktop having a plurality of multi-cooking cooking devices, in which the phase separation relay serves to disconnect all the heaters of a group of heaters from the power supply, a current in a common operating power line of all the heaters of the group of heaters is measured and judges erroneous operation of the cooktop on the basis of the measured current in the common operating power line.

Of course, it is also possible to combine the first and the second aspect as described above in any desired manner.

With the invention described above, errors that have already crept into a relay control of a hob can already be noticed without it already comes to a malfunction of the hob or to a critical condition. The reliability of the hob can thus be increased.

Fig. 1

ein vereinfachtes Blockschaltbild einer Steuerung eines Kochfeldes mit mehreren Kochstellen gemäß einem ersten Ausführungsbeispiel; und

Fig. 2

ein vereinfachtes Blockschaltbild einer Steuerung eines Kochfeldes mit mehreren Kochstellen gemäß einem zweiten Ausführungsbeispiel.

The above and other features and advantages of the invention will become more apparent from the following description of preferred, non-limiting embodiments thereof with reference to the accompanying drawings. Show:

Fig. 1

a simplified block diagram of a control of a hob with multiple hotplates according to a first embodiment; and

Fig. 2

a simplified block diagram of a control of a hob with multiple hotplates according to a second embodiment.

The present invention will now be described with reference to two preferred embodiments with reference to FIG Fig. 1 respectively. Fig. 2 explained in more detail. The same or similar components are provided in both embodiments with the same reference numerals and unnecessary repetitions of descriptions of such components is omitted.

Fig. 1 shows a highly simplified block diagram of the control of a hob according to the first preferred embodiment of the present invention. The cooktop here comprises two cooking zones, each with an electric heater 10; However, the invention is of course analogous to other hobs with other numbers of hobs applicable.

The electrical heating devices 10 are each connected to a power supply, which is formed by an operating voltage Ub and a neutral conductor Uo. The operation of a heater 10 is clocked by a clock relay 12 performed with a desired heat output. The clock relay 12 is in turn driven by a controller 14, the control and evaluation device of the invention, via a drive element 16. The drive branch of the clock relay 12 is between a supply voltage Uv and the neutral conductor Uo.

In the embodiment of Fig. 1 Furthermore, a relay coil current measuring device 18 is provided in the control branch of the clock relay 12, which detects the current through the relay coil of the clock relay 12 and conducts the measurement signal to the controller 14.

The controller 14 may then judge errors related to the drive branch.

Even if this is in Fig. 1 is not shown for simplicity, of course, for each electric heater 10 of the hob own clock relay 12 is provided with its own control branch, all of which are controlled and monitored by the controller 14.

In this very simple and thus cost-effective design of the entire control device 12-18 with a few additional components can be assessed by the relay coil of the clock relay 12 easily a faulty operation of the hob on the basis of measured by the relay coil current measuring device 18 current. As a faulty operation of the hob, in particular an error in the control of the clock relay 12 can be detected here.

As an alternative to a mechanical relay as a clock relay 12, an electronic relay or an electronic circuit breaker, such as a triac or an IGBT can be used.

Fig. 2 shows a highly simplified block diagram of the control of a hob according to the second preferred embodiment of the present invention. The hob also includes two cooking zones, each with an electric heater 10 here.

In addition to the control circuit of the electric heaters 10 of the first embodiment, this control circuit of Fig. 2 a phase separation relay 20, which can disconnect all heaters 10 or all heaters 10 a group of heaters from the power supply, ie from the operating voltage Ub or the neutral conductor Uo. The phase separation relay 20 is also controlled by the controller 14 via a corresponding drive element 22.

Further, a load current measuring device 24 is arranged in the common operating power line 26 to detect the current through all heaters 10 and all heaters 10 a group of heaters. The measurement signal generated by the load current measuring device 24 is the controller 14 for Evaluation, which can then judge a faulty operation of the cooking position based on the current through the heaters 10.

In contrast to the above first embodiment can here as a faulty operation of the cooking place in addition to the detection of a faulty control of the clock relay 12 (when the phase separation relay 20 is switched on) also an error in the clock relay 12 or in the phase separation relay 20 itself ( eg glued or jammed contact points) are detected. In a properly operated hotplate, a corresponding current flow in the operating power line 26 must result when both relays 12, 20 are turned on.

Further, in this embodiment, the controller 14 may also recognize which load on the individual branches, i. is operated in the individual groups of heaters 10. This makes it possible that the electronics can independently adjust to different variants and load conditions. An overload of individual phases can be prevented, for example.

In addition, a maximum current load in the common operating power line 26 can be ensured. The controller 14 can recognize, for example, based on the measurement signal from the load current measuring device 24 that two large consumers 10 are already switched on, and can now prevent another consumer 10 from being switched on at the same time. If only smaller consumers 10 are switched on, then the controller 14 can allow additional consumers to be switched on.

Although the present invention has been fully described in terms of two preferred embodiments, it will be apparent to those skilled in the art that various modifications and changes may be made thereto without departing from the scope of the invention.

For example, the two embodiments described above of Fig. 1 and 2 can also be combined with each other. Thus, it is conceivable, for example, to additionally provide the relay coil current measuring device 18 of the first exemplary embodiment in the control branch of the clock relay 12 in the control circuit of the second exemplary embodiment and to have its measuring signal evaluated accordingly by the controller 14.

Further, in the above embodiments, the relay coil current and / or the load current were respectively measured and evaluated during the operation of the cooking station. Alternatively, it is also possible to control the relays 12, 20 in a corresponding test mode in order to be able to detect any errors.

Although the invention has been explained with reference to the example of a cooktop with a plurality of hotplates, the present invention is analogously applicable to control devices of other consumer electronic household appliances, such as ovens, washing machines, etc., as well.

REFERENCE NUMBER LIST

10

Heating device of a cooking place

12

Timing relay

14

Control and evaluation device

16

driving element

18

Relay coil current measurement device

20

Phase separation relay

22

driving element

24

Load current measuring device

26

common operating power line

Claims (11)

Apparatus for switching a hob with at least one cooking station, with a clock relay (12) for clocking the operation of a heating device (10) of a cooking station and a control device (14) for driving (16) of the clock relay (12),
marked by
a relay coil current measuring means (18) for measuring the current through a relay coil of the clock relay (12); and
an evaluation device (14) for judging erroneous operation of the cooktop on the basis of the current measured by the relay coil current measuring means (18) through the relay coil of the clock relay (12). Device according to claim 1,
characterized,
in that the relay coil current measuring device (18) is provided in a drive branch of the clock relay (12). Apparatus for switching a hob with at least one cooking point, with a clock relay (12) for clocking the operation of a heater (10) a cooking place, a phase separation relay (20) for separating the heating device (10) of the cooking place from the power supply and a control device (14) for activating (16) the clock relay (12) and the phase separation relay (20),
marked by
a load current measuring device (24) for measuring the current through the heating device (10) of the hotplate; and
an evaluation device (14) for assessing an erroneous operation of the Hob on the basis of the measured by the load current measuring device (24) current through the heater (10). Device according to claim 3,
characterized,
that the load current measuring means (24) is provided in an operating current line (26) of the heater (10). Device according to claim 3,
characterized,
that a plurality of heating devices (10) are provided for a plurality of cooking zones; that the phase separation reiais (20) separates all heaters (10) of a group of heaters of the hotplates from the power supply; and
that the load current measuring means (24) in a common operating current line (26) of all the heating devices (10) of the group of heaters provided. Device according to one of claims 3 to 5,
characterized,
that further comprises a relay coil current measuring means (18) is provided for measuring the current through a relay coil of the relay clock (12); and
in that the evaluation device (14) is also designed to judge faulty operation of the hob on the basis of the current measured by the relay coil current measuring device (18) through the relay coil of the clock relay (12). Device according to claim 6,
characterized,
in that the relay coil current measuring device (18) is provided in a drive branch of the clock relay (12). Method for evaluating faulty operation of a hob with at least one cooking point, a clock relay (12) for clocking the operation of a heating device (10) of the cooking point and a control device (14) for driving (16) the clock relay (12)
characterized,
that a current through a relay coil of the clock relay (12) is measured and a faulty operation of the hob is judged on the basis of the measured current through the relay coil of the clock relay (12). A method of judging erroneous operation of a cooktop having at least one hotplate, a clock relay (12) for clocking the operation of a heater (10) of the hotplate, a phase disconnect relay (20) for disconnecting the hotplate (10) from the cooktop Power supply and a control device (14) for driving (16) of the clock relay (12) and the phase separation relay (20),
characterized,
that a current through the heating device (10) of the cooking zone are measured and an erroneous operation of the hob on the basis of the measured current through the heater (10) is judged. A method according to claim 9 for a cooktop having a plurality of cooking devices (10) for a plurality of cooking zones, in which the phase separation relay (20) serves for separating all heating devices (10) of a group of heating devices of the cooking devices from the power supply,
characterized,
that a current in a common operating power line (26) of all the heaters (10) of the group of heaters is measured and an erroneous operation of the cooktop is judged on the basis of the measured current in the common operating power line (26). Method according to claim 9 or 10,
characterized,
that further measured a current flows through a relay coil of the clock relay (12) and an erroneous operation of the hob is judged on the basis of the measured current through the relay coil of the relay clock (12).

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