Electrical circuit for a cooking appliance and cooking appliance

The invention relates to an electrical circuit, in particular distributed and/or modular electrical circuit, for a cooking ap pliance, in particular for a hob and/or for an induction cooking appliance, more particularly for an induction hob, and to a cor responding cooking appliance.

Cooking appliances can comprise an electrical circuit, in par ticular with at least one power supply circuit and/or an inter- face circuit. For such an electrical circuit there is an in creasing need for cost-effectiveness. However, at the same time, there is also a need in particular for monitoring, controlling and displaying of operating parameters, in particular conven iently, precisely, safely, modularly and flexibly.

However, current cooking appliances and corresponding electrical circuits do not meet an adequate number of these requirements in combination satisfyingly. It is therefore an object of the invention to provide an im proved electrical circuit and an improved cooking appliance which is both flexible and precise.

The object is solved by the invention according to the independ- ent claims, in particular according to claim 1. Improvements are provided in the dependent claims.

The invention relates to a electrical circuit, in particular distributed and/or modular electrical circuit, for a cooking ap- pliance, in particular for a hob and/or for an induction cooking appliance, more particularly for an induction hob, wherein the electrical circuit comprises

- at least one power supply circuit, in particular power board, for supplying one, two, at least one or at least two heating units with a first electrical power by means of a first power supply unit and for supplying an interface circuit with a second electrical power by means of a second power supply unit, the second power supply unit in particular being electrically iso lated from the first power supply unit, the power supply circuit comprising a first connection unit for receiving commands from, submitting parameters to and/or supplying power to the interface circuit,

- an interface circuit, in particular interface board, with at least a second connection unit for receiving power from the power supply circuit, submitting commands to and/or receiving parameters from the power supply circuit, a third, in particular wireless, connection unit for transmitting parameters to and/or for receiving commands from an, in particular mobile and/or ex ternal, operating device and preferably a or at least one fourth connection unit, in particular connector and/or wireless connec- tion, for submitting power to and/or for receiving parameters from at least one, in particular external, measurement device.

The invention in particular relates to an electrical circuit, in particular distributed and/or modular electrical circuit, for an induction hob, wherein the electrical circuit comprises a power supply circuit, in particular power board, for supplying one, two, at least one or at least two heating units with a first electrical power by means of a first power supply unit and for supplying an interface circuit with a second electrical power by means of a second power supply unit, the second power supply unit being electrically isolated from the first power supply unit, the power supply circuit comprising a first connection unit for receiving commands from, submitting parameters to and/or supplying power to the interface circuit, the interface circuit, in particular interface board, with at least a second connection unit for receiving power from the power supply cir cuit, submitting commands to and/or receiving parameters from the power supply circuit, a third wireless connection unit for transmitting parameters to and/or for receiving commands from a mobile and/or external operating device and a fourth connection unit, in particular connector, for submitting power to and/or for receiving parameters from an external measurement device. By using a power supply circuit, in particular power board, for supplying power and, in addition, an interface circuit, in par ticular interface board, for the communication with an operating device and preferably with a measurement device, it is possible to develop and/or produce and/or place both circuits, in partic- ular both boards, independently from each other. This makes it easier and cheaper to adapt the power supply circuit to specific heating units and/or to specific cooking appliances and/or to adapt the interface circuit to specific requirements. In particular, the invention makes it possible to transfer moni toring and/or controlling of the heating units in a flexible way, independent from the actual power circuit, to an external operating device like a mobile phone. At the same time, a pre cise temperature control and monitoring, in particular of multi- pie different parameters, is possible, also by using external measurement devices. Therefore, the costs for an operating de vice can decrease, as existing external operating devices can be used. A connection unit is intended to establish and maintain a con nection with another connection unit. The connection can be a wired connection or a wireless connection. A wireless connection unit can enable in particular a connection wirelessly with mul tiple measurement devices. This enables to monitor and control a variety of parameters. For establishing a wireless connection, established communication protocols can be used which easily and flexibly enable the usage of multiple measurement devices. A connection unit can in particular be understood as an interface unit.

In an embodiment, the interface circuit comprises a user inter face, the user interface in particular at least comprising a display unit and an input unit, more in particular a touch-sen- sitive display.

In an embodiment, the interface circuit comprises means for re ceiving parameters from the measurement device and for transmit ting power to the measurement device, in particular means for receiving temperature parameters from the measurement device and for transmitting power to the measurement device.

In an embodiment, the interface circuit comprises means for re ceiving parameters from the measurement device and for transmit- ting parameters to the operating device, in particular means for receiving temperature parameters from the measurement device and for transmitting temperature parameters to the operating device.

In an embodiment, the interface circuit comprises means for re- ceiving commands from the operating device and for transmitting commands to the power supply circuit, in particular means for receiving control commands for controlling the at least one heating unit from the operating device and for transmitting the commands to the power supply circuit.

In an embodiment, the at least one measurement device comprises a temperature measuring unit, in particular temperature probe and/or at least one measuring unit for humidity, weight, vibra tion or chemical composition. In an embodiment, the at least one measurement device is a food probe and/or is a device for measuring the temperature of at least one item to be cooked on the at least one heating unit.

In an embodiment, the at least one measurement device comprises a fifth connection unit for exchanging temperature parameters with and/or receiving power from the fourth connection unit. In an embodiment, the interface circuit comprises at least one fourth wireless connection unit for receiving parameters from multiple, in particular external, measurement devices, wherein the measurement devices comprise a temperature measuring unit, in particular temperature probe, and/or at least one measuring device for humidity, weight, vibration or chemical composition of the items to be cooked.

The usage of an external measurement device can make it possible to use the measurement device for different cooking devices, for example for a cooking hob and for an oven. The usage of multi ple, in particular external, measurement devices makes it possi ble to measure different and/or multiple parameters. This option can increase the options for cooking significantly, as a larger number of parameters can be measured. In particular, when an ex- ternal operating device is used, the control algorithm software can be adapted to consider the amended parameters.

In particular, the operating device can be configured to trans mit commands to the power supply circuit. Transmitting the com- mands to the power supply circuit in the operating device can be based preferably on a software or application, whereas the soft ware or application can more preferably be adaptable to the at least one parameter as provided by at least one measuring unit. The adaption can preferably be performed directly by the user, for example by selecting manually or automatically the provided parameters and/or by obtaining and/or downloading an adequate software, in particular an adequate application or app.

In an embodiment, the operating device is a mobile phone.

In a further embodiment, the operating device can be a mobile device, for example a tablet or a similar operating device. The operating device can in particular comprise a display unit and/or an input unit, more in particular a touch screen.

In an embodiment, the at least one power supply circuit is sup plied with power by at least one external supply signal.

In an embodiment, the at least one external supply signal is provided as an AC voltage signal and/or mains voltage with a voltage between 220 V and 380 V, in particular between 220 V and 250 V, and/or with a single voltage phase. Preferably, the ex ternal supply signal is provided by only two wires.

In an embodiment, at least one internal DC supply signal is pro vided by at least one DC signal generating unit for supplying at least one DC-Bus with electrical power.

In an embodiment, the second power supply unit comprises a power conversion circuit for converting an external supply signal into different, in particular DC and/or isolated, output voltages.

In an embodiment, the second power supply unit supplies the in terface circuit and/or at least one unit of the first power sup ply unit with an, in particular isolated, power.

In an embodiment, the second power supply unit supplies at least a first voltage, in particular DC voltage, and a second voltage, in particular DC voltage, different from the first voltage, wherein in particular the first DC voltage is 5V and/or the sec ond DC voltage is 18V.

A power supply can in particular be an electrical power supply and/or a supply with electrical energy.

If an isolated 5V DC supply voltage is supplied, preferably a Class II or double insulation is used. Preferably, the or a sup ply voltage, in particular the first and/or the second voltage, is supplied in such a way that it does not require a safety con nection to electrical earth or ground. This is in particular ad vantageous for supplying one or more external measurement de vices with electrical power.

In particular, at least two layers of insulating material are used for the insulation of the voltage supply unit. By this in sulation, it can preferably be achieved that a single failure will not result in a dangerous voltage becoming exposed to the user so that it might avoid an electric shock for the user. In an embodiment, this can preferably be achieved without relying on an earthed metal casing.

In an embodiment, the at least one power supply circuit, in par ticular the first power supply unit, comprises a relay, a fre quency adapting unit, at least one DC signal generating unit, one, at least one or at least two heating frequency generating units and/or a microcontrol unit.

In an embodiment, the frequency adapting unit is a filter, wherein the filter is constituted in particular by an LC filter.

In an embodiment, the at least one DC signal generating unit is a rectifier, wherein the rectifier in particular is a bridge rectifier and/or is constituted by diodes, wherein the at least one DC signal generating unit preferably comprises a surge pro tection unit and/or a bus voltage detection unit.

In an embodiment, the or each heating frequency generating unit comprises an inverter, in particular generator, in particular using IGBT's and/or a half bridge and/or using a quasiresonant signal.

In an embodiment, the first electrical power is supplied to the at least one heating unit by means of at least one heating fre quency generating unit, in particular by means of at least one heating frequency signal.

In an embodiment, the or each heating frequency generating unit comprises a current detection unit, an IGBT voltage detection unit, an IGBT temperature detection unit and/or an IGBT driver unit.

In an embodiment, the first connection unit and the second con nection unit are interconnected by a serial communication inter face, in particular a galvanically isolated serial communication interface, preferably by means of at least one opto-coupling de vice.

In an embodiment, the third connection unit comprises means for transmitting parameters to the operating device and/or for re ceiving commands from the operating device, in particular means for transmitting temperature parameters to and/or for receiving temperature parameters from the operating device. In an embodiment, the fifth connection unit is connected with the fourth connection unit by a cable and/or a wireless connec tion, in particular using a wireless communication protocol, more in particular Bluetooth and/or IEEE 802.15.1.

In an embodiment, the first connection unit is connected with the second connection unit by a cable and/or a wireless connec tion.

In an embodiment, the third connection unit is connected with the operating device by a cable and/or a wireless connection.

In an embodiment, one, at least one or each board, in particular the power board and/or the interface board, is a printed circuit board, PCB.

The invention also relates to a cooking appliance, in particular hob and/or induction cooking appliance, more particularly induc tion hob, with an electrical circuit according to the invention.

In an embodiment, the cooking appliance comprises one, at least one, in particular at least two, at least three or at least four heating units, wherein each heating unit preferably comprises at least one inductor, more preferably at least one coil.

In an embodiment, the cooking appliance comprises the operating device and/or the at least one measurement device.

The present invention will be described in further detail with reference to the drawings, in which

FIG 1 shows an electrical circuit according to a preferred embodiment of the present invention. Even though the figure shows, as an example, two heating units 90, 91, an, in particular second, embodiment of the invention can also comprise an electrical circuit for supplying only one heating unit 90.

FIG 1 shows an electrical circuit, in particular distributed and/or modular electrical circuit 2, for a cooking appliance, in particular for an induction cooking appliance, more particularly for an induction hob.

In the embodiment of FIG 1, the electrical circuit 2 comprises a power supply circuit 20, in particular power board, for supply ing two heating units 90, 91 with a first electrical power 36,

37 by means of a first power supply unit 21.

In a second embodiment, the electrical circuit 2 comprises a power supply circuit 20, in particular power board, for supply ing a single heating unit 90 with a first electrical power 36 by means of a first power supply unit 21.

In addition, the power supply circuit 20 is configured for sup plying an interface circuit 70 with a second electrical power 63 by means of a second power supply unit 22.

The second power supply unit 22 is electrically isolated from the first power supply unit 21. The power supply circuit 20 com prises a first connection unit 49 for receiving commands from, submitting parameters to and/or supplying power to the interface circuit 70.

The electrical circuit 2 comprises, furthermore, the interface circuit 70, in particular interface board, with at least a sec ond connection unit 71 for receiving power from the power supply circuit 20, submitting commands to and/or receiving parameters from the power supply circuit 20. The electrical circuit 2 also comprises a third, in particular wireless, connection unit 73 for transmitting parameters to and/or for receiving commands from a, in particular mobile and/or external, operating device 80.

In addition, the interface circuit 70 comprises a fourth connec tion unit 72, in particular connector, for submitting power to and/or for receiving parameters from at least one, in particular external, measurement device 81. In particular, the interface circuit 70 can comprises a fourth connection unit 72, in partic ular connector, for submitting power to and/or for receiving pa rameters from multiple external measurement devices 81. The interface circuit 70 comprises a user interface, the user interface at least comprising a display unit and an input unit, more in particular a touch-sensitive display.

The interface circuit 70 comprises means for receiving parame- ters from the measurement device 81 and for transmitting power to the measurement device 81, in particular means for receiving temperature parameters from the measurement device 81 and for transmitting power to the measurement device 81. The interface circuit 70 comprises means for receiving parame ters from the measurement device 81 and for transmitting parame ters to the operating device 80, in particular means for receiv ing temperature parameters from the measurement device 81 and for transmitting temperature parameters to the operating device 80.

The interface circuit 70 comprises means for receiving commands from the operating device 80 and for transmitting commands to the power supply circuit 20, in particular means for receiving control commands for controlling the heating units 90, 91 from the operating device 80 and for transmitting the commands to the power supply circuit 20. In a second embodiment, the interface circuit 70 comprises means for receiving commands from the operating device 80 and for transmitting commands to the power supply circuit 20, in partic ular means for receiving control commands for controlling the single heating unit 90 from the operating device 80 and for transmitting the commands to the power supply circuit 20.

The measurement device 81 comprises a temperature measuring unit 81, in particular temperature probe and/or at least one measur ing unit for humidity, weight, vibration or chemical composi- tion.

The measurement device 81 can in particular be a food probe. The measurement device 81 can be a device for measuring the tempera ture of at least one item to be cooked on the at least one heat- ing unit 90, 91.

The measurement device 81 comprises a fifth connection unit 82 for exchanging temperature parameters with and/or receiving power from the fourth connection unit 72.

In a further embodiment, the interface circuit 70 can comprise at least one fourth wireless connection unit 72 for receiving parameters from multiple, in particular external, measurement devices 81, wherein the measurement devices 81 comprise a tem- perature measuring unit 81, in particular temperature probe, and/or at least one measuring device for humidity, weight, vi bration or chemical composition of the items to be cooked. In the embodiment, the operating device 80 is a mobile phone 80. The operating device can be also a different mobile device, for example a tablet or a similar device.

In particular, the operating device 80 is configured to transmit commands to the power supply circuit 20. Transmitting the com mands to the power supply circuit 20 in the operating device 80 can be based on a software or application, whereas the software or application is preferably adaptable to the at least one pa rameter as provided by at least one measuring unit 81. The adap tion can preferably be performed directly by the user, for exam ple by selecting manually or automatically the provided parame ters and/or by obtaining and/or downloading an adequate soft ware, in particular an adequate application or app.

The at least one power supply circuit 20 is supplied with power by at least one external supply signal 39.

The at least one external supply signal 39 is provided as an AC voltage signal and/or mains voltage 10 with a voltage between 220 V and 380 V, in particular between 220 V and 250 V and with a single voltage phase. The external supply signal is provided by only two wires.

The at least one internal DC supply signal 38 is provided by at least one DC signal generating unit 33, in particular for sup plying at least one DC-Bus with electrical power.

The second power supply unit 22 comprises a power conversion circuit 60 for converting an external supply signal into differ ent isolated DC output voltages 61, 62, 63. The second power supply unit 22 supplies the interface circuit 70 and at least one unit of the first power supply unit 21 with an isolated power. The second power supply unit 22 supplies at least a first volt age, in particular DC voltage, and a second voltage, in particu lar DC voltage, different from the first voltage. In particular, the first DC voltage is 5V and/or the second DC voltage is 18V. In particular, an isolated 5V DC supply voltage is supplied to the interface circuit.

The power supply circuit 20 comprises a relay 31, a frequency adapting unit 32, at least one DC signal generating unit 33, one, at least one or at least two heating frequency generating units 34, 35 and a microcontrol unit 50.

In particular, the external supply signal 39 in fed into the re lay 31. The output of the relay 31 is fed into the frequency adapting unit 32. The output of the frequency adapting unit 32 is fed into at least one DC signal generating unit 33.

In a first embodiment, the output of the at least one DC signal generating unit 33 is fed into at least two heating frequency generating units 34, 35. The output of the at least two heating frequency generating units 34, 35 is fed into the at least two heating units 90, 91.

In a second embodiment, which does not comprise the heating fre quency generating unit 35 and the heating unit 91, the output of the at least one DC signal generating unit 33 is fed into the heating frequency generating unit 34. The output of the heating frequency generating units 34 is fed into the heating unit 90. The frequency adapting unit 32 is a filter, wherein the filter is constituted in particular by an LC filter.

The at least one DC signal generating unit 33 is a rectifier, wherein the rectifier in particular is a bridge rectifier and/or is constituted by diodes, wherein the at least one DC signal generating unit 33 preferably comprises a surge protection unit 42 and a bus voltage detection unit 43. In a first embodiment, the at least two heating frequency gener ating units 34, 35 are inverters, in particular generators, in particular using IGBT's and/or a half bridge and/or using a qua siresonant signal. The first electrical power is supplied to the heating units 90, 91 by means of e heating frequency generating units 34, 35, in particular by means of heating frequency signals 36, 37.

The at least two heating frequency generating units 34, 35 com- prise a current detection unit 44, an IGBT voltage detection unit 45, an IGBT temperature detection unit 46 and an IGBT driver unit 47.

In a second embodiment, the heating frequency generating unit 34 is an inverter, in particular generator, in particular using one or at least one IGBT and/or a half bridge and/or using a qua siresonant signal.

The first electrical power is supplied to the heating unit 90, 91 by means of the heating frequency generating unit 34, 35, in particular by means of a heating frequency signal 36, 37. In the second embodiment, the heating frequency generating unit 34 comprises a current detection unit 44, an IGBT voltage detec tion unit 45, an IGBT temperature detection unit 46 and an IGBT driver unit 47.

The current detection unit 44, the IGBT voltage detection unit 45, the IGBT temperature detection unit 46 and the IGBT driver unit 47 as well as the fan driver unit 48 are supplied with power by means of a DC voltage supply of the power conversion circuit 60 and are in interaction with the microcontrol unit 50

The first connection unit 49 and the second connection unit 71 are interconnected by a serial communication interface, in par ticular a galvanically isolated serial communication interface, preferably by means of at least one opto-coupling device.

The third connection unit 73 comprises means for transmitting parameters to the operating device 80 and/or for receiving com mands from the operating device 80, in particular means for transmitting temperature parameters to and/or for receiving tem perature parameters from the operating device.

The fifth connection unit 82 is connected with the fourth con nection unit 72 by a cable and/or a wireless connection, in par- ticular using a wireless communication protocol, more in partic ular Bluetooth and/or IEEE 802.15.1.

The first connection unit 49 is connected with the second con nection unit 71 by a cable and/or a wireless connection.

The first connection unit 73 is connected with the second con nection unit 80 by a cable and/or a wireless connection. One, at least one or each board 20, 70, in particular the power board and/or the interface board, is a printed circuit board, PCB. The cooking appliance according to the embodiments can be an in duction hob as shown in FIG. 1 and comprises one, at least one, in particular at least two, at least three or at least four heating units 90, 91, wherein each heating unit preferably com prises at least one inductor, more preferably at least one coil.

The cooking appliance 1 comprises the operating device 80 and/or the at least one measurement device 81.

List of reference numerals

1 Cooking appliance

2 Electrical circuit

20 Power supply circuit

21 First power supply unit

22 Second power supply unit

31 Relay

32 Frequency adapting unit

33 DC signal generating unit

34, 35 Heating frequency generating units

38 DC supply signal

39 External supply signal

42 Surge protection unit

43 Bus voltage detection unit

44 Current detection unit

45 IGBT voltage detection unit

46 IGBT temperature detection unit

47 IGBT driver unit

48 Fan driver unit

49 Connection unit

50 Microcontrol unit 60 Power conversion circuit

61,62,63 DC Outputs 70 Interface circuit

71,72,73 Connection units

80 Operating device

81 Measurement device

82 Connection unit

90, 91 Heating units