EP2774455A2

EP2774455A2 - Induction heating device

Info

Publication number: EP2774455A2
Application number: EP12806668.5A
Authority: EP
Inventors: Sergio Llorente Gil; Daniel PALACIOS THOMAS; Hector Sarnago Andia
Original assignee: BSH Bosch und Siemens Hausgeraete GmbH
Current assignee: BSH Hausgeraete GmbH
Priority date: 2011-11-04
Filing date: 2012-10-30
Publication date: 2014-09-10
Also published as: CN103891401B; WO2013064967A2; WO2013064967A3; CN103891401A

Abstract

The invention relates to an induction heating device, in particular an induction hob device, comprising at least one heating frequency unit (20, 22, 24, 26), at least one induction heating unit (30, 32, 34, 36), which is intended to be operated by the heating frequency unit (20, 22, 24, 26), and at least one control unit (14). According to the invention, in order to achieve increased efficiency, the control unit (14) is intended to operate the heating frequency unit (20, 22, 24, 26) in a pulsed manner in at least one operating mode in which a heating power (Pmean) that can be delivered to the induction heating unit (30, 32, 34, 36) by the heating frequency unit (20, 22, 24, 26) in continuous operation is requested for the at least one induction heating unit (30, 32, 34, 36).

Description

induction heating

The invention is based on an induction heating device according to the preamble of claim 1.

There are induction hobs are known, which have an inductor in a

Operating state in which a heating power is requested, which can not be supplied continuously, is operated pulsed.

The object of the invention is, in particular, a generic device with improved properties in terms of high electrical efficiency

provide. The object is achieved by the features of

Patent claim 1 solved, while advantageous embodiments and modifications of the invention can be taken from the dependent claims.

The invention is based on an induction heating device, in particular a

Induction hob device, comprising at least one heating frequency unit, at least one induction heating unit, which is intended to be operated by the heating frequency unit, and at least one control unit.

It is proposed that the control unit be provided to the

Heizfrequenzeinheit in at least one operating mode, in which for the at least one induction heating unit, a heating power, in particular a low to medium

Heating power is requested, which is available in a continuous operation of the heating frequency unit to the induction heating unit to operate pulsed. Under one

"Heating frequency unit" is to be understood in particular as an electrical unit which generates an oscillating electrical signal, preferably with a switching frequency of at least 1 kHz, in particular of at least 10 kHz, advantageously of at least 20 kHz, in particular of not more than 100 kHz, for an induction heating unit.

In particular, the heating frequency unit is intended to be one of which

Induktionsheizeinheit required, maximum electrical power of at least 1000 W, in particular at least 2000 W, advantageously at least 3000 W, preferably at least 3500 W, to provide. In particular, the heating frequency unit comprises at least one inverter which preferably has at least two, preferably series-connected, bidirectional unipolar switches which are formed, in particular, by a transistor and a diode connected in parallel, and particularly advantageously at least one parallel to the bidirectional unipolar switches

Damping capacity, which is in particular formed by at least one capacitor has. As a result, a high-frequency power supply of the induction heating unit can be provided. An "induction heating unit" is to be understood in particular as a unit having at least one induction heating element. In particular, in an operating state in which the induction heating unit with high-frequency

AC, all induction heaters of the induction heating unit, preferably at the same time, supplied with high-frequency alternating current. An "induction heating element" is to be understood, in particular, as a wound electrical conductor, preferably in the form of a circular disk, which is arranged in at least one

Operating state of high-frequency alternating current is flowed through. The

Induktionsheizelement is preferably intended to convert electrical energy into a magnetic alternating field, which is intended to be in a

metallic, preferably at least partially ferromagnetic, heating means, in particular a Gargeschirr, eddy currents and / or Ummagnetisierungseffekte cause, which are converted into heat. A "control unit" is to be understood in particular as meaning an electronic unit which is preferably at least partially integrated in a control and / or regulating unit of an induction heating device and which is preferably provided for, at least the

Heating frequency unit to control and / or to regulate. Preferably, the

Control unit, a computing unit and in particular in addition to the arithmetic unit, a memory unit with a stored therein control and / or control program, which is intended to be executed by the arithmetic unit. By "provided" is meant in particular specially programmed, designed and / or equipped. "Required heating power" is to be understood in particular as an adjustment made by an operator via an operating unit.

In particular, a value of an electrical power, in particular in watts, and / or a power level, which is preferably assigned by the control unit to an electrical power, can be set. Alternatively, the requested heating power can be set by the control unit as part of a cooking program. A heating power is particularly available in a "continuous operation" when an electrical efficiency of a whole used heating electronics, in particular at least the

Heizfrequenzeinheit, a rectifier unit, the induction heating unit and / or the control unit is greater than at least 85%, in particular at least 90%, advantageously at least 93%, preferably at least 95%. In particular, is one

Power loss of the heating electronics a maximum of 15%, in particular a maximum of 10%, advantageously a maximum of 7%, preferably a maximum of 5%, a heating power over the

Induction heating unit is delivered to a heating medium. In particular, one is

Heating power available in continuous operation, if a switching frequency of

Heizfrequenzeinheit necessary to produce the heating power is less than 120 kHz, in particular less than 1 10 kHz, preferably less than 100 kHz. A "pulsed operation" is to be understood in particular as an operating state in which a heating frequency unit alternately, preferably periodically alternately, provides no current in pulsed phase high frequency alternating current or in idle phases .. In particular, a pulse phase duration is at least 0.1 s, in particular at least 0.5 s Advantageously, at least 1 s, preferably at least 3 s, in particular not more than 15 min, advantageously not more than 10 min, preferably not more than 5 min The control unit is provided to select a pulse power, ie heat power during pulse phases, such that a heating power averaged over time In particular, the heating powers are at least essentially the same in different, in particular successive, preferably immediately successive, pulse phases, below that two values are "essentially" the same, it shall be understood in particular that a difference in the W maximum of 10%, in particular not more than 5%, preferably not more than 1% of a sum of the values. In particular, a resting phase duration in at least one operating state is at most 100%, in particular at most 50%, advantageously at most 25%, preferably at most 10%, of a duration of a preceding pulse phase. A "low to medium" heating power is to be understood in particular to mean a heating power which corresponds to a maximum of 70%, in particular a maximum of 50%, preferably a maximum of 30% of a maximum heating power, in particular a maximum power of the heating frequency unit 1, 5 kW, advantageously at most 1.2 kW, preferably at most 1 kW. By using higher heating powers, in particular increased electrical efficiency can be achieved. Furthermore, it is proposed that the control unit in at least one

Operating mode is provided to set a pulse power as a function of the requested heating power via at least one assignment function. In particular, the mathematical function is stored in a memory unit of the control unit, in particular in the form of a table, In particular, the assignment function is designed as a step function, alternatively any, preferably monotonous, in particular monotonically increasing Functions are conceivable, in particular a simple control can be achieved.

It is also proposed that the control unit be provided to assign at least two, in particular at least three, advantageously at least four, subregions of an entire range of possible heating powers each having different pulse powers. A "subarea" of a region should in particular be understood to mean a coherent region which lies completely within the region. <br/> <br/> Preferably, the subregions cover the entire region together. </ RTI> Preferably, an overlap of different subregions is limited to their edges It is further proposed that the control unit be in at least one

Operating state is provided to at least one of the sub-areas to assign a pulse power that is at least 1%, in particular at least 3%, preferably at least 8% greater than a maximum heat output of the sub-area. In particular, high efficiency can be achieved.

It is advantageously proposed that the control unit in at least one

Operating mode is provided, a pulse phase spacing at least as a function of at least one characteristic, in particular a characteristic which assigns a power to a minimum pulse phase spacing, preferably a flicker characteristic,

set. A "pulse phase distance" is to be understood as meaning, in particular, a distance between start times of two pulse phases, preferably immediately consecutive pulse phases

Operating mode consecutive pulse phase intervals at least substantially equal. A flicker characteristic should in particular be understood as a characteristic curve which determines, at least, how large a pulse-phase distance as a function of a pulse power should be to disturbances in a power grid and / or

Comfort restrictions, such as flickering light, to avoid. In particular, increased comfort and / or improved network stability can be achieved.

Furthermore, it is proposed that the control unit be provided, at least in the at least one, at least as a function of an operator input

Switch operating mode between pulsed operation and continuous operation. In particular, the induction heating device has at least one

Operating element, in particular a touch-sensitive control surface and / or a menu item in a control menu, which is provided to provide the control unit with a signal for switching. In particular, increased comfort can be achieved.

Furthermore, it is proposed that the control unit is provided to define at least one pulse phase duration and / or at least one pulse power as a function of at least one time characteristic. Under a "time characteristic" should

In particular, a parameter to be understood that reflects a time period and / or a time. In particular, the time parameter is intended to specify a maximum and / or minimum and / or exact idle-phase duration.

In particular, the time parameter has a value of at least 0 s, in particular at least 2 s, advantageously at least 5 s, in particular a maximum of 30 s, advantageously a maximum of 20 s, preferably a maximum of 10 s. In particular, the control unit is to

provided to set the time characteristic in response to an operator input. In particular, increased comfort, flexible control and / or uniform heating behavior can be achieved.

Such a device is particularly advantageously arranged in an induction hob and / or in an oven with induction heating.

Further advantages emerge from the following description of the drawing. In the

Drawing embodiments of the invention are shown. The drawing, the Description and claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations. 1 shows a hob according to the invention in a schematic view from above,

a pulsed operation in a schematic diagram,

different assignment functions in a schematic

Diagram,

a schematic flicker characteristic,

a dependent on a heating efficiency in a schematic diagram and

a schematic temperature profile with pulsed operation.

FIG. 1 shows a domestic appliance 10 designed as an induction hob, with a domestic appliance 10

Induction hob device trained induction heater 12. The

Induction heater 12 has four formed as an inverter

Heating frequency units 20, 22, 24, 26 on. Furthermore, the induction heating device 12 has four induction heating units 30, 32, 34, 36 formed as inductors, which are each intended to be operated by different heating frequency units 20, 22, 24, 26. The induction heating units 30, 32, 34, 36 are disposed below a cooking plate and are intended to plate on the hob set Garware, which is positioned above the induction heating units 30, 32, 34, 36 to heat. Furthermore, the induction heating device 12 has a control unit 14 and an operator interface 16. The user interface 16 is intended to allow an operator to control heating power for the

Induction heating units 30, 32, 34, 36 to request and currently set

Output power levels to display units. The control unit 14 is provided to process inputs of the user interface 16, to control displays of the display units of the user interface 16 and to control the heating frequency units 20, 22, 24, 26 such that the induction heating units 30, 32, 34, 36 deliver powers on average that correspond to requested heating powers via the user interface 16. The control unit 14 is provided to the heating frequency units 20, 22, 24, 26 respectively in an operating mode in which a heating power P _me on is requested for the corresponding induction heating unit 30, 32, 34, 36, in a continuous operation of the heating frequency unit 20th , 22, 24, 26 to the induction heating unit 30, 32, 34, 36 is available to operate pulsed (Figure 2). The induction heating unit 30, 32, 34, 36 is provided to generate in the operating mode periodically alternately during pulse phases 60, 62 with a pulse phase duration t ₀ N high-frequency alternating current, which leads to a pulse power P _pu i _s , and during resting phases 61, 63 with a rest period t _off no high-frequency alternating current to produce. An average heating output corresponding to the requested heating power P _me Toggle

A permanently deliverable power is determined by a performance-dependent efficiency η of electronics of the induction heating device 12 (FIG. 5). Here are for

Average cookware, heating power P, which are above a minimum heating power P _min , permanently deliverable, since for this an efficiency η of the electronics is greater than a minimum efficiency r | _min . The minimum efficiency r | _min is 95%. This results in a minimum heating power P _min of 500 W. The control unit 14 is provided in the one operating mode to a pulse power Ppuis in response to the requested heating power P _me on a

Assign assignment function f-ι (Figure 3). The assignment function f-1 is as

Step function formed. The control unit 14 is provided to two

Divisions 52, 54 of an entire range 50 of possible heating powers P _mean each assign different pulse powers P ₅₂ , P ₅₄ . The control unit 14 is provided in the one operating state to allocate a pulse power P ₅₂ to the partial area 52 which is 10% greater than a maximum heating power P ₅ 2max of the partial area 52. A pulse power P _{54 of} the partial area 54 corresponds to a maximum heating power P5 ₄ max of the partial area 54. The partial area 52 extends from 0 W to 2000 W. The partial area 52 is assigned a pulse power P ₅₂ of 2200 W. The partial area 54 extends from 2000 W to 3300 W. The partial area 54 is assigned a pulse power P ₅₄ of 3300 W. An upper limit of the partial area 54 corresponds to a maximum heating power of the heating frequency units 20, 22, 24, 26. The control unit 14 is provided in the one operating mode to a

Pulse phase distance t _F | _icker depending on a Flickerkennlinie f _F ii _C ker set. FIG. 4 shows, by way of example, a patch characteristic f _F ii _C ker, as defined by the national standard. The following information refers to the Spanish Flickernorm. Thus, the control unit 14 assigns the pulse power P ₅₂ a pulse phase distance t ₅₂ of 32 s and the pulse power P _{54 to} a pulse phase distance t ₅₄ of 170 s. The limits of

Subareas 52, 54, the associated pulse powers P ₅₂ , P ₅₄ and the associated pulse phase intervals t ₅₂ , t ₅₄ are stored in an allocation table in a memory unit of the control unit 14. A requested heat output P _me on becomes such a

_Pulse power P _pU | _S and a pulse phase distance t _F | assigned to _icker . To set the requested heating power P _mean , a pulse phase duration t ₀ N is after the

Calculation rule t ₀ N = Pmean / Ppuis ^x t _F | _icker to choose.

Furthermore, the control unit 14 is provided depending on a

Change operator input via the operator interface 16 in the one operating mode between a pulsed operation and a continuous operation. This allows an operator to flexibly switch between a power saving mode and a conventional mode. Furthermore, many different variants for assignment functions f _1; f ₂ , f ₃ , f ₄ conceivable (Figure 2). In particular, the assignment function f _{2 can be designed} as a step function with more than 2 stages, in particular any number of stages, for example 4 stages. Alternatively, the assignment function f _{3 may be formed} as a continuous function, wherein a pulse power P _pU | _S is constant as a function of the requested heating power P _me in a first partial area, in a central partial area is constantly greater than the requested heating power P _me and in an upper area constantly corresponds to a maximum heating power. Furthermore, it is conceivable that the

Control unit 14 is provided, depending on an operator input via the operator interface 16 to select one of different assignment functions that are provided by the control unit for election. For example, an operator may specify a number of levels and the control unit calculates and / or determines a suitably suitable staircase function.

The pulsed operation produces a periodically fluctuating temperature profile with a fluctuation range ΔΤ (FIG. 6). In order to keep the fluctuation range ΔΤ low, can be provided in a further variant, the control unit 14 to

_{Pulse phase duration} t ₀ N and / or pulse power P _pU | _S depending on one

Set time parameter. As a time parameter here is a maximum

Rest phase duration determined. This can for example be 8 s. It results in view of the Flickerkennlinie f _F ii _C ker the assignment function f ₄ (Figure 2).

Furthermore, embodiments are conceivable in which the control unit 14 is provided for the Heizfrequenteinheit 20, 22, 24, 26 at heating power P _m ean, which are greater than low to medium heat outputs, ie, for example, greater than 1000 W to operate continuously.

Embodiments of the invention are also conceivable in which a heating frequency unit is provided to operate a plurality of induction heating units alternately.

reference numeral

10 domestic appliance toN pulse phase duration

12 induction heater toff resting phase duration

14 control unit 'mean requested heating power

16 User interface P Heating power

20 Heating frequency unit Pmin minimum heating power

22 Heating frequency unit Ppuls Pulse power

24 Heating frequency unit P ₅₂ Pulse power

26 Heating frequency unit P54 Pulse power

30 induction heating unit P52max maximum heating power

32 induction heating unit P54max maximum heating power

34 Induction heating unit fi Dis pattering

36 Induction heating unit f ₂ Not available

50 Area f ₃ To be re duced

52 Subarea To c ommendation

54 Subarea fFlicker Flicker characteristic

60 pulse phase tFlicker pulse phase distance

61 Resting phase t ₅ 2 Pulse-phase interval

62 pulse phase tö4 pulse phase distance

63 Dormant phase ΔΤ Fluctuation width

η efficiency

Ilmin minimum efficiency

Claims

claims

Induction heating device, in particular induction hob device, with at least one heating frequency unit (20, 22, 24, 26), at least one

Induction heating unit (30, 32, 34, 36) intended to be removed from

Heizfrequenzeinheit (20, 22, 24, 26) to be operated, and at least one control unit (14), characterized in that the control unit (14) is provided, the Heizfrequenzeinheit (20, 22, 24, 26) in at least one operating mode in that a heating power (P _me an) is requested for the at least one induction heating unit (30, 32, 34, 36), which in a continuous operation from the heating frequency unit (20, 22, 24, 26) to the induction heating unit (30, 32 , 34, 36) is available to operate pulsed. 2. Induction heater according to claim 1, characterized in that the control unit (14) is provided in at least one operating mode to a pulse power (P _pu i _s ) in response to the requested heating power (Pmean) via at least one assignment function (f _1; f ₂ , f3, f ₄ ).

Induction heater according to claim 2, characterized in that the

Control unit (14) is provided to at least two sub-areas (52, 54) of an entire area (50) of possible heating powers (P _mean ) each assign different pulse powers (P ₅₂ , Ps ₄ ).

Induction heating device according to claim 3, characterized in that the control unit (14) is provided to assign at least one of the subregions (52) a pulse power (P ₅₂ ) which is at least 1% greater than a maximum heating power (P ₅ 2max) of the subregion (52).

Induction heating device according to one of the preceding claims, characterized in that the control unit (14) in at least one

Operating mode is provided to set a pulse phase distance (t _F ii _C ker, 2, ts ₄ ) at least in dependence on at least one characteristic (fFMcker).

6. Induction heater according to one of the preceding claims, characterized in that the control unit (14) is provided to switch at least in response to an operator input at least in the at least one operating mode between a pulsed operation and a continuous operation.

7. induction heating device according to any one of the preceding claims, characterized in that the control unit (14) is provided to set a pulse phase duration (. ₀ N) and / or the pulse power (P _pu i _s ) as a function of at least one time characteristic.

8. Domestic appliance with an induction heater (12) according to one of

previous claims.

9. A method for controlling an induction heating device (12) according to any one of claims 1 to 7.