Induction energy transmission system

Abstract

The invention relates to an induction energy transmission system (10), in particular an induction cooking system, comprising a supply unit (12) which has at least one supply induction element (14) for inductively providing energy, at least one standing unit (18, 20) which has at least one receiving unit (22) comprising at least one receiving induction element (24) for receiving the inductively provided energy, and a control and / or regulating unit (16) for controlling and / or regulating the supply unit (12) in order to transmit energy between the supply unit (12) and the receiving unit (22). In order to improve the actuation process, the invention proposes that the control and / or regulating unit (16) is designed to calculate an output-frequency transmission function (98) for the energy transmission on the basis of at least one measurement at a measurement point (100) and to determine at least one working point for the energy transmission using the calculated output-frequency transmission function (98).

Description

[0001] Induction energy transfer system

[0002] The invention relates to an induction energy transmission system according to the preamble of claim 1, an induction hob of an induction energy transmission system according to claim 13, a small household appliance of an induction energy transmission system according to claim 14 and a method for operating an induction energy transmission system according to the preamble of claim 15.

[0003] Induction energy transmission systems for the inductive transmission of energy from a primary coil of a supply unit to a secondary coil of a mounting unit are already known from the prior art. For example, induction hobs are known which, in addition to inductive heating of cookware, are also designed for the inductive supply of energy to small household appliances. However, with regard to a power-frequency transfer function, considerable differences can arise from one small household appliance to another. For example, a first power-frequency transfer function of a first small household appliance could have only one maximum, whereas a second power-frequency transfer function of a second small household appliance might comprise two maximums.In addition, the power-frequency transfer function may also depend significantly on an offset of the primary coil relative to the secondary coil and / or the presence of metallic and ferromagnetic materials in the installation unit and / or the environment of the supply unit.

[0004] The object of the invention is, in particular but not limited to, to provide a generic device with improved control properties. This object is achieved according to the invention by the features of claims 1 and 15, while advantageous embodiments and further developments of the invention can be found in the subclaims.

[0005] The invention is based on an induction energy transmission system, in particular an induction cooking system, with a supply unit which has at least one supply induction element for inductively providing energy, with at least one installation unit which has at least one receiving unit with at least one receiving induction element for receiving the inductively provided energy, and with a control and / or regulating unit for controlling and / or regulating the supply unit for energy transmission between the supply unit and the receiving unit.

[0006] It is proposed that the control and / or regulating unit is provided to calculate and / or simulate a power-frequency transfer function for the energy transfer between the supply unit and the receiving unit based on at least one measurement at a measuring point and to determine at least one operating point for the energy transfer between the supply unit and the receiving unit based on the calculated power-frequency transfer function.

[0007] Such a configuration can advantageously improve control of the supply unit. In particular, efficiency can be increased. Furthermore, operational reliability can be increased, with system components, in particular of the supply unit and / or the installation unit, preferably being able to be operated in a safe area. This can also increase user safety. Furthermore, the setup time of the induction energy transmission system can advantageously be reduced. Finally, the user experience can be improved.

[0008] The induction energy transmission system has at least one main functionality in the form of wireless energy transmission, in particular a wireless energy supply to installation units. In an advantageous embodiment, the induction energy transmission system is designed as an induction cooking system with at least one further main function that differs from a pure cooking function, in particular at least an energy supply and operation of small household appliances. For example, the induction energy transmission system could be designed as an induction oven system and / or as an induction grill system. In particular, the supply unit could be designed as part of an induction oven and / or as part of an induction grill. The induction energy transmission system designed as an induction cooking system is preferably designed as an induction hob system.The supply unit is then designed, in particular, as part of an induction hob. In a further advantageous embodiment, the induction energy transmission system is designed as a kitchen energy supply system and, in addition to a primary function of supplying energy and operating small household appliances, can also be provided for providing cooking functions.

[0009] A "supply unit" is understood to mean a unit that inductively provides energy in at least one operating state and, in particular, has a primary functionality in the form of energy provision. To provide energy, the supply unit has at least one supply induction element, which, in particular, has at least one coil, in particular at least one primary coil, and / or is designed as a coil, and which, in particular, provides energy inductively in the operating state.The supply unit could have at least two, in particular at least three, advantageously at least four, particularly advantageously at least five, preferably at least eight, and particularly preferably a plurality of supply induction elements, each of which could inductively provide energy in the operating state, in particular to a single receiving induction element or to at least two or more receiving induction elements of at least one installation unit and / or at least one further installation unit. At least some of the supply induction elements could be arranged in close proximity to one another, for example in a row and / or in the form of a matrix. Preferably, the supply unit has at least one compensation capacitor, which can be connected electrically in parallel or electrically in series with the supply induction element and which can be provided in particular for reactive power compensation.

[0010] A “control and / or regulating unit” is to be understood as an electronic unit that is intended to control and / or regulate at least the supply unit. The control and / or regulating unit comprises a computing unit and, in particular, in addition to the computing unit, a memory unit with at least one control and / or regulating program stored therein, which is intended to be executed by the computing unit. The control and / or regulating unit has at least one inverter unit. In the operating state, the inverter unit preferably performs a frequency conversion and, in particular, converts a low-frequency AC voltage on the input side into a high-frequency AC voltage on the output side. The low-frequency AC voltage preferably has a frequency of at most 100 Hz. The high-frequency AC voltage preferably has a frequency of at least 1000 Hz.The inverter unit is preferably provided to adjust the energy inductively provided by the at least one supply induction element by adjusting the high-frequency alternating voltage, in particular via a frequency and / or a duty cycle. The control and / or regulating unit preferably comprises at least one rectifier. The inverter unit has at least one inverter switching element. The inverter switching element preferably generates an oscillating electrical current for operating the at least one supply induction element, preferably with a frequency of at least 15 kHz, in particular of at least 17 kHz and advantageously of at least 20 kHz. The inverter unit preferably comprises at least two inverter switching elements, which are preferably designed as bipolar transistors with an insulated gate electrode, and particularly advantageously at least one damping capacitor.

[0011] A "installation unit" is to be understood as a unit which, in at least one operating state, receives energy inductively and at least partially converts the inductively received energy into at least one further form of energy to provide at least one main function. For example, the energy received inductively by the installation unit could be converted, in particular directly, into at least one further form of energy, such as heat, in the operating state. Alternatively or additionally, the installation unit could have at least one electrical consumer, for example an electric motor or the like. The installation unit has at least one receiving unit with a receiving induction element for receiving the inductively provided energy.The receiving unit could, for example, have at least two, in particular at least three, advantageously at least four, particularly advantageously at least five, preferably at least eight and particularly preferably several receiving induction elements, which could each inductively receive energy, in particular from the supply induction element, in particular in the operating state.

[0012] The installation unit could, for example, be designed as a cooking utensil. The cooking utensil preferably has at least one food receiving space and, in the operating state, converts the inductively received energy at least partially into heat for heating food arranged in the food receiving space. The installation unit designed as a cooking utensil preferably has at least one further unit for providing at least one further function that goes beyond and / or differs from merely heating food. For example, the further unit could be designed as a temperature sensor or as a stirring unit or the like.

[0013] Alternatively, the installation unit could be part of a small household appliance or designed as a small household appliance. Preferably, the small household appliance is a location-independent household appliance which has at least the recording induction element and at least one functional unit which, in an operating state, provides at least one household appliance function. In this context, “location-independent” should be understood to mean that the small household appliance can be positioned freely in a household by a user, and in particular without aids, in particular in contrast to a large household appliance which is fixedly positioned and / or installed in a specific position in a household, such as an oven or a refrigerator. Preferably, the small household appliance is designed as a small kitchen appliance and, in the operating state, provides at least one main function for processing food.The small household appliance could, for example, be designed as, but not limited to, a food processor and / or as a blender and / or as a stirrer and / or as a grinder and / or as a kitchen scale or as a kettle or as a coffee maker or as a rice cooker or as a milk frother or as a deep fryer or as a toaster or as a juicer or as a cutting machine or the like.

[0014] The receiving induction element of the receiving unit comprises at least one secondary coil and / or is designed as a secondary coil. In an operating state of the installation unit, the receiving induction element supplies at least one consumer of the installation unit with electrical energy. Furthermore, it is conceivable for the installation unit to have an energy storage device, in particular an accumulator, which is provided to store electrical energy received via the receiving induction element in a charged state and to make it available to supply the functional unit in a discharged state. Preferably, the receiving unit has at least one load resistor and / or at least one compensation capacitor, which is electrically connected in parallel or in series with the receiving induction element and which can be provided in particular for reactive power compensation.

[0015] The induction energy transmission system preferably has at least one support plate for supporting the support unit. A "support plate" is understood to mean at least one, in particular plate-like, unit that is intended for supporting at least one support unit and / or for supporting at least one item of food. The support plate could, for example, be designed as a worktop, in particular as a kitchen worktop, or as a partial area of ​​at least one worktop, in particular at least one kitchen worktop, in particular of the induction energy transmission system. Alternatively or additionally, the support plate could be designed as a hob plate.The installation plate designed as a hob plate could, in particular, form at least part of a hob outer housing and, in particular, together with at least one outer housing unit, to which the installation plate designed as a hob plate could, in particular, be connected in at least one assembled state, form at least a large part of the hob outer housing. Preferably, the installation plate is made of a non-metallic material. For example, the installation plate could be formed at least largely from glass and / or glass ceramic and / or Neolith and / or Dekton and / or wood and / or marble and / or stone, in particular natural stone, and / or laminate and / or plastic and / or ceramic.In this document, location designations such as "below" or "above" refer to the installed state of the mounting plate, unless explicitly stated otherwise. In the installed state, the supply unit is preferably located below the mounting plate.

[0016] The induction energy transmission system preferably comprises a communication unit. The communication unit is provided in particular for preferably bidirectional wireless data transmission, i.e. preferably for both wireless reception and wireless transmission of data, between the control and / or regulating unit and the installation unit. The communication unit preferably has at least one communication element which is connected to the control and / or regulating unit and is provided in particular for wireless reception and / or transmission of data. The communication unit preferably has at least one further communication element which is part of the installation unit and is provided in particular for wireless reception and transmission of data.The communication unit could be provided for wireless data transmission between the installation unit and the control and / or regulating unit via RFID, Wi-Fi, Bluetooth, ZigBee, or for wireless data transmission according to another suitable standard. Preferably, the communication unit is provided for wireless data transmission between the installation unit and the control and / or regulating unit via NFC. Preferably, the control and / or regulating unit is provided to wirelessly receive at least one parameter, preferably from a parameter set, from the installation unit, specifically by means of the communication unit.

[0017] A "parameter set" is understood to mean a plurality of at least two parameters that the control and / or regulating unit uses, in particular, to control the supply and based on which the control and / or regulating unit controls, in particular, the energy inductively provided by the supply unit according to a type of installation unit and / or according to a current operating state of the installation unit, which can be selected, in particular, by a user of the induction energy transmission system. The parameter set could include at least one constant structural and / or geometric characteristic of the supply induction element and / or the receiving induction element.Structural and / or geometric parameters could include, for example, but are not limited to, a shape and / or size, in particular a radius and / or inner diameter and / or an outer diameter, and / or a cross-sectional area and / or a number of windings and / or a material and / or a spatial position of the receiving induction element within the installation unit and / or a vertical distance of the supply induction element from the installation plate and / or the like.Preferably, at least one parameter of the operating parameter set comprises an electrical characteristic, in particular a time-varying one, of the supply induction element and / or of the receiving induction element, for example amounts of electrical resistances and / or impedances in a primary circuit of the supply unit and / or in a secondary circuit of the receiving unit and / or inductances, in particular self-inductances, and / or magnetic flux densities of the supply induction element and / or of the receiving induction element and / or a resonance frequency and / or a material constant, for example a magnetic permeability of a magnetic flux bundling element of the supply unit and / or of the receiving unit.Furthermore, at least one parameter of the operating parameter set can comprise at least one operating characteristic of the installation unit, for example a maximum power and / or a minimum power and / or number of power levels and / or a number and / or type of operable electrical loads and / or a voltage and / or current required in an operating state.

[0018] The power-frequency transfer function specifically represents a relationship between the power delivered by the supply induction element and the frequency of the current flowing in the supply induction element. The power-frequency transfer function can include a single maximum at a specific frequency or multiple maximums at different frequencies.

[0019] The control and / or regulating unit is particularly designed to apply a current at the frequency of the measuring point to the supply induction element during the measurement at the measuring point and to measure the output power of the supply induction element and / or at least one physical quantity related to the power, in particular a voltage and / or a current. The control and / or regulating unit is preferably designed to perform the measurement at the measuring point during at least one half-wave of a mains supply voltage, in particular to obtain an average across different voltage values ​​of the mains supply voltage.The control and / or regulating unit can in particular be provided to repeat the measurement at the measuring point and / or the calculation of the power-frequency transfer function repeatedly, in particular periodically, for example after every x-th half-wave of a mains supply voltage, where x can in particular stand for a natural number greater than zero.

[0020] The control and / or regulating unit is particularly designed to select the operating point for a continuous power supply to the recording unit. The operating point is, in particular, a specific frequency and can additionally have a specific duty cycle, in particular one different from 0.5.

[0021] The control and / or regulating unit is preferably provided to monitor a positioning of the installation unit relative to the supply unit and / or the energy transfer between the supply unit and the installation unit and, particularly preferably, to repeat the measurement at the measuring point and / or the calculation of the power-frequency transfer function and / or the determination of the operating point in the event of a change in the positioning and / or at least one parameter of the energy transfer, for example a power output of the supply induction element and / or an effective current intensity in the supply induction element, in particular by a certain limit value.

[0022] In this document, numerals such as "first" and "second," which precede certain terms, serve only to distinguish between objects and / or to correlate objects with each other and do not imply a total number and / or ranking of the objects. In particular, a "second object" does not necessarily imply the presence of a "first object."

[0023] "Intended" should be understood as specifically programmed, designed, and / or equipped. The fact that an object is intended for a specific function should be understood as meaning that the object fulfills and / or performs this specific function in at least one application and / or operating state.

[0024] It is further proposed that the control and / or regulating unit be configured to select a frequency for the measuring point that is high enough to ensure that the power consumption of the recording induction element during energy transfer between the supply unit and the recording unit is sufficiently low. This can increase operational reliability, as electronic components can be protected. The selected frequency of the measuring point is preferably above 60 kHz, preferably above 65 kHz, and particularly preferably above 70 kHz.

[0025] Advantageously, the control and / or regulating unit is provided to calculate at least one coupling factor between the supply unit and the receiving unit based on the measurement at the measuring point, whereby an actual coupling between the supply induction element and the receiving induction element can advantageously be taken into account. Furthermore, influences of a positioning of the receiving induction element relative to the supply induction element can be taken into account. The coupling factor describes in particular a proportion of a magnetic flux that is shared by the supply induction element and the receiving induction element in the operating state and can assume values ​​between 0 and 1, with a value of 1 describing an ideal magnetic coupling, which is not achievable in practice due to magnetic stray fluxes.

[0026] It is also proposed that the control and / or regulating unit be provided to use an equivalent impedance between the supply unit and the receiving unit to determine the coupling factor. Such a configuration can advantageously achieve a particularly simple and reliable determination of the at least one coupling factor. The equivalent impedance between the supply unit and the receiving unit describes a total impedance of an imaginary common electrical circuit of the receiving unit and the supply unit during the energy transfer from the supply induction element to the receiving induction element. Preferably, the control and / or regulating unit is provided to measure the equivalent impedance in the operating state on a primary circuit comprising the supply induction element, wherein the control and / or regulating unit can have corresponding measuring devices for this purpose.

[0027] Furthermore, it is proposed that the control and / or regulating unit be configured to determine an equivalent resistance from the real part of the equivalent impedance and / or to directly measure the equivalent resistance. This advantageously further improves the determination of at least one coupling factor. The equivalent resistance describes ohmic components of the total impedance of the imaginary shared electrical circuit of the receiving unit and the supply unit during an inductive energy transfer from the supply induction element to the receiving induction element.

[0028] Furthermore, it is proposed that the control and / or regulating unit be configured to determine an equivalent inductance from the imaginary part of the equivalent impedance. This advantageously further improves the determination of at least one coupling factor. The equivalent inductance describes the inductive components of the total impedance of the imaginary common electrical circuit of the receiving unit and the supply unit during an inductive energy transfer from the supply inductance element to the receiving inductance element.Preferably, the control and / or regulating unit is designed to use, in addition to the measured variable, additional known variables when calculating the coupling factor, in particular as initial values ​​of an iterative calculation method, namely, in particular, a self-inductance of the supply inductance element, a self-inductance of the receiving inductance element, a load resistance of the receiving unit, a resonance capacitance of the receiving unit, and / or the frequency of the measuring point. These variables can be stored in the memory unit of the control and / or regulating unit at the factory and / or transmitted from the installation unit to the control and / or regulating unit via the communication unit.

[0029] It is also proposed that the control and / or regulating unit is provided to determine a first coupling factor between the supply unit and the receiving unit from the equivalent resistance. It is further proposed that the control and / or regulating unit is provided to determine a second coupling factor between the supply unit and the receiving unit from the equivalent inductance. Furthermore, it is proposed that the control and / or regulating unit is provided to use the first coupling factor or the second coupling factor as the coupling factor or to calculate the coupling factor from the first coupling factor and the second coupling factor, for example by averaging. Ideally, the first coupling factor and the second coupling factor are identical to one another.

[0030] Furthermore, it is proposed that the control and / or regulating unit be configured to calculate, using the coupling factor, a corrected self-inductance of the supply inductance element, a corrected self-inductance of the receiving inductance element, and / or a corrected load resistance of the mounting unit. This allows the self-inductances and / or the load resistance actually occurring during coupling to be taken into account, particularly since the aforementioned variables depend heavily on the actual position of the receiving inductance element relative to the supply inductance element. This enables advantageously improved control of the supply inductance element.The control and / or regulating unit is particularly designed to correct the self-inductances by multiplying them by a respective correction factor, wherein the correction factors are preferably determined by means of multivariable regression. The correction factors take into account, in particular, the position, in particular a vertical distance and / or a horizontal offset, of the receiving inductance element relative to the supply inductance element.

[0031] Advantageously, the control and / or regulating unit is provided to improve values ​​for the corrected self-inductance of the supply inductance element, the corrected self-inductance of the receiving inductance element, and / or the corrected load resistance of the mounting unit using an iterative calculation method with at least one iteration step. This allows the calculated power-frequency transfer function to be further improved, in particular to bring it even closer to reality, especially since an actual coupling between the supply unit and the receiving unit can be better approximated.In this case, the control and / or regulating unit is provided in particular to repeat the calculation of the at least one coupling factor and to use the corrected values ​​instead of the initial values ​​for the self-inductance of the supply inductance element, for the self-inductance of the receiving inductance element and / or for the load resistance of the receiving unit, in particular in order to then obtain further corrected values ​​of these variables, which preferably then approach reality further with each iteration.

[0032] If the control and / or regulation unit is designed to use the same values ​​measured at the measuring point in each iteration step, efficiency can be advantageously increased. In particular, rapid execution of the method and, consequently, a rapid start of energy transfer between the supply unit and the receiving unit can be achieved.

[0033] It is further proposed that the control and / or regulating unit be configured to perform at least 2, in particular at least 3, and at most 10, preferably at most 7, particularly preferably at most 5, iteration steps, thereby achieving an advantageous compromise between high accuracy and rapid determination. A first iteration step is understood to mean a first repetition of the calculation.

[0034] In a preferred embodiment of the invention, it is proposed that the control and / or regulating unit is provided to take into account at least one further measurement at a further measuring point, in particular during at least one half-wave of the mains supply voltage, when calculating the power-frequency transfer function for the energy transfer between the supply unit and the receiving unit. This advantageously allows the power-frequency transfer function to be further improved. In particular, further, in particular unknown, tolerances can be taken into account, such as manufacturing tolerances of components, in particular inductances, capacitances and / or ohmic resistances, and / or tolerances of a measuring unit of the supply unit for measuring at the measuring points.

[0035] Advantageously, the control and / or regulating unit is provided to select a further frequency for the further measuring point, taking into account at least one power tolerance and the previously calculated power-frequency transfer function, whereby safe operation can be achieved. In particular, the power-frequency transfer function previously determined with regard to the measuring point, which preferably already has a high degree of accuracy, can be used to select the further frequency. In this case, a frequency is preferably selected as the further frequency at which, according to the previously determined power-frequency transfer function, a required power is delivered less a tolerance amount. The tolerance amount could, for example, be a maximum power tolerance. In addition, an adjustment of the duty cycle would be conceivable to maintain a safety margin.

[0036] In a particularly preferred embodiment of the invention, it is proposed that the control and / or regulating unit be designed to improve the power-frequency transfer function by taking into account the additional measurement at the additional measuring point. This can preferably achieve a further improvement in the accuracy of the power-frequency transfer function based on the previous calculations.

[0037] In a further embodiment of the invention, it is proposed that the control and / or regulating unit is provided to carry out the same calculation steps for the measurement at the further measuring point as for the measurement at the measuring point. This can particularly advantageously achieve a further increase in accuracy, since the calculations can be repeated for a different frequency. The control and / or regulating unit is particularly provided to use the previously calculated corrected self-inductances and / or the corrected load resistance and the further frequency when calculating the at least one coupling factor in order to in turn obtain further corrected self-inductances and / or a further corrected load resistance. Here, too, a further improvement of the aforementioned variables would be conceivable using an iterative calculation method.

[0038] The control and / or regulation unit is particularly designed to further optimize the power-frequency transfer function based on the calculation results at the additional measuring point. This preferably takes into account the corrected parameters for the self-inductances and load resistance calculated based on the additional measuring point and / or the fact that there are now two measuring points through which the power-frequency transfer function must pass. Classic fitting methods, neural networks, and / or machine learning can be used for optimization.

[0039] It is also proposed that the control and / or regulating unit be designed to select the point in the ZVS (“Zero Voltage Switching”) switching range with the lowest losses as the operating point, thereby achieving particularly efficient and gentle operation. The control and / or regulating unit is designed in particular to estimate losses in electronics, in particular the inverter, and / or in the supply induction element and / or in the receiving induction element and accordingly to select a suitable operating point for operation of the installation unit at which the required power is provided according to the power-frequency transfer function. The control and / or regulating unit is preferably designed to take into account an effective current intensity, the shutdown current of an IGBT of the inverter and / or other known parameters of the IGBT when estimating the losses at the inverter.The control and / or regulating unit is preferably designed to take into account an effective current strength and / or other known parameters of the electronic components when estimating the losses of other electronic components. The control and / or regulating unit is advantageously designed to take into account a conductor length, a number of windings, an effective current, and / or at least one material property when estimating the losses of the supply induction element and / or the receiving induction element.

[0040] The invention further relates to a method for operating an induction energy transmission system, in particular an induction cooking system, with a supply unit which has at least one supply induction element for inductively providing energy and with at least one installation unit which has at least one receiving unit with at least one receiving induction element for receiving the inductively provided energy, wherein the supply unit is controlled and / or regulated for energy transmission between the supply unit and the receiving unit.

[0041] It is proposed that a power-frequency transfer function for the energy transfer between the supply unit and the receiving unit is calculated based on at least one measurement at a measuring point and that at least one operating point for the energy transfer between the supply unit and the receiving unit is determined based on the calculated power-frequency transfer function.

[0042] Such a configuration can advantageously improve control of the supply unit. In particular, efficiency can be increased. Furthermore, operational reliability can be increased, with system components, in particular of the supply unit and / or the installation unit, preferably being able to be operated in a safe area. This can also increase user safety. Furthermore, the setup time of the induction energy transmission system can advantageously be reduced. Finally, the user experience can be improved.

[0043] The induction energy transmission system is not intended to be limited to the application and embodiment described above. In particular, the induction energy transmission system may have a number of individual elements, components, and units that differs from the number stated herein to fulfill a functionality described herein.

[0044] Further advantages will become apparent from the following description of the drawings. The drawings illustrate an exemplary embodiment of the invention. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also expediently consider the features individually and combine them into useful further combinations.

[0045] They show:

[0046] Fig. 1 shows an induction energy transmission system with a supply unit, a control and / or regulating unit for controlling and / or regulating the supply unit, a mounting unit and a further mounting unit, each of which comprises a receiving unit, in a schematic representation,

[0047] Fig. 2 is a schematic representation of a supply induction element of the supply unit and a receiving induction element of one of the installation units together with a magnetic flux bundling element of the supply unit and a magnetic flux bundling element of the receiving unit of one installation unit,

[0048] Fig. 3 is a schematic electrical equivalent circuit diagram illustrating an inductive energy transfer between the supply induction element and the receiving induction element,

[0049] Fig. 4 is a schematic electrical T-equivalent circuit of the equivalent circuit from Fig. 3,

[0050] Fig. 5 two schematic diagrams showing influencing factors on the self-inductances of the supply induction element and the receiving induction element,

[0051] Fig. 6 four schematic representations of possible arrangements between the supply induction element and the receiving induction element,

[0052] Fig. 7 is a schematic process flow diagram of a method for operating the induction energy transmission system and

[0053] Fig. 8 shows a power-frequency transfer function for the energy transfer between the supply unit and the receiving unit with a measuring point marked.

[0054] Figure 1 shows a schematic representation of an induction energy transmission system 10. The induction energy transmission system 10 comprises a supply unit 12. The supply unit 12 has at least one supply induction element 14 for the inductive provision of energy. In the present case, the supply unit 12 comprises a total of four supply induction elements 14, although any other number is conceivable.

[0055] The induction energy transmission system 10 has a mounting unit 18. The mounting unit 18 has a receiving unit 22 with a receiving induction element 24 for receiving the energy inductively provided by the supply unit 12. In the present case, the mounting unit 18 is designed as a small household appliance 72, specifically a food processor. The induction energy transmission system 10 has a further mounting unit 20. The further mounting unit 20 also comprises a receiving unit 22 with a receiving induction element 24 for receiving the energy inductively provided by the supply unit 12. The further mounting unit 20 is designed as a further small household appliance 73, specifically a kettle. The induction energy transmission system 10 can have further mounting units (not shown).The following description refers to the installation unit 18, but also applies analogously to the other installation unit 20.

[0056] The induction energy transmission system 10 has a mounting plate 58 for mounting the mounting units 18.

[0057] The induction energy transmission system 10 is embodied as an induction cooking system and includes an induction cooktop 60. In this case, the support plate 58 is embodied as a cooktop plate of the induction cooktop 60. Alternatively, the support plate 58 could also be embodied as a kitchen worktop.

[0058] The induction energy transmission system 10 has a control and / or regulating unit 16 for controlling and / or regulating the supply unit 12 for energy transmission between the supply unit 12 and the receiving unit 22. The control and / or regulating unit 16 is provided to use a parameter set for controlling and / or regulating the supply unit 12 and to receive at least one parameter of the parameter set from the receiving unit 22.

[0059] For this purpose, the induction energy transmission system 10 has a communication unit (not shown). The communication unit is provided for wireless data transmission between the installation unit 18 and the control and / or regulating unit 16. In the present case, the communication unit is also provided for wireless data transmission between the further installation unit 20 and the control and / or regulating unit 16. The communication unit has a communication element which is connected to the control and / or regulating unit 16 and is provided for wireless transmission and reception of data. The communication unit has a further communication element which is arranged in the installation unit 18 and is provided for wireless transmission and reception of data.The communication unit also has a further communication element, which is arranged in the further installation unit 20 and is provided for wirelessly transmitting and receiving data. In this case, the communication unit is designed as an NFC communication unit and is provided for wireless data transmission via NFC between the control and / or regulating unit 16 and the installation unit 18 and / or the further installation unit 20.

[0060] The control and / or regulating unit 16 comprises a memory unit and a computing unit. For controlling and / or regulating and supplying power to the supply unit 12, the control and / or regulating unit 16 further comprises an inverter unit, which is provided in a known manner for providing high-frequency alternating current for the supply induction element 14.

[0061] In an operating state of the induction energy transmission system 10, the control and / or regulating unit 16 receives several parameters from the installation unit 18 wirelessly, specifically via the communication element of the communication unit, and stores them in the memory unit. Further parameters of the parameter set are also stored in the memory unit of the control and / or regulating unit 16. The parameter set includes a self-inductance of the supply induction element 14. The parameter set includes a self-inductance of the receiving induction element 24. The parameter set can also include a mutual inductance between the supply induction element 14 and the receiving induction element 24. For example, the parameter received wirelessly from the installation unit 18 could be the self-inductance of the receiving induction element 24.In addition to the two parameters mentioned, the parameter set may include further parameters, which may also be stored in the memory unit and / or received wirelessly from the installation unit 18 by the control and / or regulating unit 16 via the communication element. Furthermore, the computing unit may be configured to calculate some parameters of the parameter set from other parameters of the parameter set or to obtain them by measurement.

[0062] Figure 3 shows a simplified schematic electrical circuit diagram illustrating an inductive energy transfer between the supply induction element 14 of the supply unit 12 and the receiving induction element 24 of the receiving unit 22 of the installation unit 18, which are arranged at a vertical distance 44 from each other. Part of the supply unit 12 is shown in Figure 3 as a primary circuit 90. In addition to the supply induction element 14, the primary circuit 90 includes a compensation capacitor 74 and an electrical resistor 76. The primary circuit 90 also includes an AC voltage source 78, which is connected in series with the compensation capacitor 74, the supply induction element 14, and the electrical resistor 76. The electrical resistor 76 represents the electrical losses during operation of the primary circuit 90.At least one inverter (not shown) of the inverter unit can be considered as the AC voltage source 78 in the primary circuit 90.

[0063] The receiving unit 22 of the installation unit 18 is shown in Figure 3 as a secondary circuit 92, which includes the receiving induction element 24 as well as a compensation capacitor 80 connected in series therewith and an electrical resistor 82. The electrical resistor 82 represents the total electrical load in an operating state of the installation unit 18, assuming, for the sake of simplicity, a purely resistive load. Of course, the induction energy transmission system 10 would also be suitable for operating installation units with a total electrical load composed of resistive loads and capacitive loads and / or inductive loads, since these loads can be converted into an equivalent purely resistive load by the computing unit of the control and / or regulating unit 16.

[0064] The control and / or regulating unit 16 is provided to calculate a power-frequency transfer function 98 for the energy transfer between the supply unit 12 and the receiving unit 22, based on at least one measurement at a measuring point 100, and to determine at least one operating point, i.e. a specific frequency and a specific duty cycle, for the energy transfer between the supply unit 12 and the receiving unit 22, based on the calculated power-frequency transfer function 98.

[0065] Figure 8 shows an exemplary power-frequency transfer function 98 of the installation unit 18. The power transmitted between the supply unit 12 and the receiving unit 22 is plotted on an ordinate 94 in kW. The operating frequency of the inverter in kHz is plotted on an abscissa 96. The power-frequency transfer function 98 has two maxima in this case. The control and / or regulating unit 16 is provided to first calculate the power-frequency transfer function

[0066] 98 and then select a suitable operating point for the operation of the installation unit 18.

[0067] For this purpose, the control and / or regulating unit 16 first performs the measurement at measuring point 100, specifically during a half-wave of a mains supply voltage. The control and / or regulating unit 16 is provided to select such a high frequency for the measuring point 100 that the power consumption of the receiving induction element 24 during the energy transfer between the supply unit 12 and the receiving unit 22 is reliably sufficiently low. In this case, a frequency of 74 kHz was selected for the measurement. The control and / or regulating unit 16 is provided to calculate a coupling factor between the supply unit 12 and the receiving unit 22 based on the measurement at the measuring point 100.

[0068] The corresponding physical principles for this are explained below:

[0069] The schematic electrical equivalent circuit shown in Figure 3 can be considered a two-port network in network theory. Figure 4 shows a schematic T-equivalent circuit of a two-port of the schematic electrical equivalent circuit shown in Figure 3.

[0070] The control and / or regulating unit 16 is provided to use an equivalent impedance 40 between the supply unit 12 and the receiving unit 22 during operation. The equivalent impedance 40 describes a total impedance of the primary circuit 90 and the secondary circuit 92 of the simplified equivalent circuit diagram shown in Figure 3 during an inductive energy transfer between the supply induction element 14 of the supply unit 12 and the receiving induction element 24 of the receiving unit 22. In the T-equivalent circuit diagram of Figure 4, the equivalent impedance 40 is composed of an equivalent impedance 84 for the primary circuit 90, an equivalent impedance 86 for the secondary circuit 92, and an equivalent impedance 88, which takes into account the mutual inductance occurring between the supply induction element 14 and the receiving induction element 24 during the inductive energy transfer.The inductive energy transfer between the supply induction element 14 and the receiving induction element 24 can be modeled using the following system of equations (1):. where Zu is a self-impedance of the primary circuit 90, Z22 is a self-impedance of the secondary circuit 92, Z12 is a mutual impedance induced by the supply induction element 14 during the inductive energy transfer in the receiving induction element 24, and Z 2irepresent a mutual impedance induced by the receiving induction element 24 during the inductive energy transfer in the supply induction element 14. Furthermore, h represents an alternating current flowing through the supply induction element 14 in the operating state in the primary circuit 90, l2 represents an alternating current flowing through the receiving induction element 24 in the secondary circuit 92, and V represents the alternating voltage provided by the alternating voltage source 78. Since the mutual impedances Z12 and Z21 have the same magnitude in this case, the system of equations (1) can be simplified to the system of equations (1') as follows:

[0071] Furthermore, the relationships shown in the following equations (2) to (5) apply, whereby winding losses of the supply induction element 14 and the receiving induction element 24 as well as heat losses are neglected:

[0072] In equations (2) to (5), j stands for the imaginary unit, w for the angular frequency, Lu for the self-inductance of the supply inductance element 14, Ci for the capacitance of the compensation capacitor 74 in the primary circuit 90 (see Figure 3), L22 for the self-inductance of the receiving inductance element 24, L12 for the mutual inductance, R oad for the electrical resistance 82 and C2 for the capacitance of the compensation capacitor 80 in the secondary circuit 92 (see Figure 3), TT for the angular number and f for the frequency of the alternating voltage provided by the alternating voltage source 78 (see Figure 3).

[0073] If winding losses of the supply induction element 14 and the receiving induction element 24 as well as heat losses are to be taken into account, an additional summand Rn,i can be added to equations (2) for Zn and in equation (4) for Z22. 0Ss or R22 0SS, respectively. The magnitude of these summands can be determined in advance in dedicated tests and stored in the memory unit of the control and / or regulating unit 16 or in the installation unit 18.

[0074] The equivalent impedance 40 can be determined by the control and / or regulating unit 16 through the above-mentioned measurement on the primary circuit 90. Using Kirchhoff's rules, the following equation (6) can be set for the equivalent impedance 40: where in equation (6) the symbol Z eq stands for the equivalent impedance 40. At measuring point 100, the voltage V and the current h are measured.

[0075] To calculate the coupling factor, the simplified electrical equivalent circuit shown in Figure 3 or, alternatively, the schematic T-equivalent circuit of the two-port of the simplified electrical equivalent circuit shown in Figure 3 shown in Figure 4 can be used. The equivalent impedance 40 describes the total impedance of the primary circuit 90 and the secondary circuit 92 of the simplified equivalent circuit shown in Figure 3 for an inductive energy transfer between the supply induction element 14 of the supply unit 12 and the receiving induction element 24 of the receiving unit 22.In Figure 3, the equivalent impedance 84 represents the difference between the intrinsic impedance Zn of the primary circuit 90 and the mutual inductance Z12, the equivalent impedance 86 represents the difference between the intrinsic impedance Z22 of the secondary circuit 92 and the mutual inductance Z12, and the equivalent impedance 88 represents the mutual inductance Z12, so that the above equation (6) can also be derived directly from the T-equivalent circuit as an alternative to using Kirchhoff's rules.

[0076] Furthermore, the equivalent impedance 40 is a complex quantity and can therefore also be represented in the form of the following equation (7): where Z eq for the equivalent impedance 40, R eq for an equivalent resistance (not shown) and L eq represent an equivalent inductance (not shown) of the schematic circuits shown in Figures 3 and 4.

[0077] The control and / or regulating unit 16 is provided to determine the equivalent resistance R eqfrom the real part of the measured equivalent impedance 40. From equation (7) the following relationship can be derived using the above equations (2), (3), (4), (6):

[0078] The control and / or regulating unit 16 is further provided to determine the equivalent inductance L eq from the imaginary part of the measured equivalent impedance 40. From equation (7) the following relationship can be derived using equations (2), (3), (4), (6):

[0079] From the equivalent resistance R eq a first coupling factor between the supply unit 12 and the receiving unit 22 can be determined. In addition, a second coupling factor between the supply unit 12 and the receiving unit 22 can be determined from the equivalent inductance L eqThe following relationship exists between the self-inductance Lu of the supply inductance element 14, the self-inductance L22 of the receiving inductance element 24, the mutual inductance L12 and the first coupling factor or the second coupling factor, as shown in the following equation (10): where k generally stands for one of the coupling factors. By inserting equation (10) into equation (8) and solving for k, the first coupling factor can be calculated from the equivalent resistance R using the following equation (11). eq be determined: where kR eq stands for the first coupling factor. By inserting equation (10) into equation (9) and solving for k, the second coupling factor can be calculated from the equivalent inductance L using the following equation (12). eq be determined: where ki_ eq stands for the second coupling factor.

[0080] As can be seen from equations (11) and (12), the coupling factors kR eq , ki_ eq a relationship between the self-inductance Lu of the supply inductance element 14, the self-inductance L22 of the receiving inductance element 24 and the mutual inductance L12. In general, the coupling factors kR eq , ki_ eq a portion of a magnetic flux which is shared by the supply induction element 14 and the receiving induction element 24 in the operating state. The coupling factors k Req , k Leq can take values ​​between 0 and 1, where a value of 1 would represent an ideal magnetic coupling. In practice, however, magnetic stray losses occur, so that the values ​​of the coupling factors kR eq , ki_eq are less than 1. In theory, the first coupling factor kR eq , which can be determined from equation (12), and the second coupling factor ki_eq , which can be determined from equation (13), assume identical values ​​for all frequencies f of the alternating voltage provided by the alternating voltage source 78. However, investigations by the applicant have shown that the first coupling factor k Req and the second coupling factor k Leq differ in practice. It turns out that the first coupling factor k Req changes only slightly with changes in the self-inductance of the supply inductance element 14, the self-inductance of the receiving inductance element 24 and the mutual inductance, whereas the second coupling factor ki_ eq shows greater variance for the same changes.

[0081] After the measurement at measuring point 100, the control and / or regulating unit 16 has all the information needed to calculate the two coupling factors: The self-inductance Lu of the supply inductance element 14, in particular with its tolerances, and in particular also the capacitance Ci of the compensation capacitor 74 are stored at the factory in the memory unit of the control and / or regulating unit 16. The self-inductance L22 of the receiving inductance element 24, in particular with its tolerances, the resistance Rioad for the electrical resistor 82 (load resistor), in particular with its tolerances, and the capacitance C2 of the compensation capacitor 80 are stored at the factory in the installation unit 18 and are transmitted to the control and / or regulating unit 16 via the communication unit. The values ​​for the angular frequency w, the equivalent resistance R eq and the equivalent inductance L eqknows the control and / or regulating unit 16 from the measurement at measuring point 100.

[0082] In the present embodiment, the control and / or regulating unit 16 uses the coupling factor k = k Req In alternative designs, a coupling factor k = k Leq conceivable or a coupling factor k, which consists of k Req and k Leq is calculated, for example by averaging.

[0083] Investigations by the applicant have shown that the vertical distance 44 and a horizontal offset 46 (see Figure 6) between the supply induction element 14 and the receiving induction element 24 each have a major influence on the self-inductances L11, L22 of the supply induction element 14 and the receiving induction element 24 and thus, according to equation (12), also on the coupling factor, in particular due to the presence of magnetic flux bundling elements 48, 50 of the supply unit 12 and / or the receiving unit 22 (see Figure 2).

[0084] Figure 5 shows two schematic diagrams illustrating influencing variables on the self-inductances of the supply induction element 14 and the receiving induction element 24 in an operating state of the induction energy transmission system 10.

[0085] The coupling factor between the supply induction element 14 and the receiving induction element 24 is plotted as a dimensionless parameter on an abscissa 96 of the left-hand diagram in Figure 5. The self-inductance Lu of the supply induction element 14 is plotted in pH on a left-hand ordinate 94 of the left-hand diagram. The vertical distance 44 between the supply induction element 14 and the receiving induction element 24 is plotted in mm on a right-hand ordinate 95 of the left-hand diagram. A first series of measurements 112 in the left-hand diagram shows the curve of the Lu of the supply induction element 14 and the coupling factor as a function of the vertical distance without a horizontal offset 46 (cf. Figure 6) between the supply induction element 14 and the receiving induction element 24.A second series of measurements 114 in the left-hand diagram shows the course of the self-inductance Lu of the supply induction element 14 and the coupling factor as a function of the vertical distance 44 with a horizontal offset 46 of 20 mm between the supply induction element 14 and the receiving induction element 24. A third series of measurements 116 in the left-hand diagram shows the course of the self-inductance Lu of the supply induction element 14 and the coupling factor as a function of the vertical distance 44 with a horizontal offset 46 of 40 mm between the supply induction element 14 and the receiving induction element 24.

[0086] The coupling factor between the supply induction element 14 and the receiving induction element 24 is plotted as a dimensionless parameter on an abscissa 96 of the right-hand diagram in Figure 5. The self-inductance L22 of the receiving induction element 24 is plotted in pH on a left-hand ordinate 94 of the right-hand diagram. The vertical distance 44 between the supply induction element 14 and the receiving induction element 24 is plotted in mm on a right-hand ordinate 95 of the right-hand diagram. A first series of measurements 118 in the right-hand diagram shows the course of the self-inductance L22 of the receiving induction element 24 and the coupling factor as a function of the vertical distance 44 without a horizontal offset 46 between the supply induction element 14 and the receiving induction element 24.A second series of measurements 120 in the right-hand diagram shows the course of the self-inductance L22 of the receiving induction element 24 and the coupling factor as a function of the vertical distance 44 with a horizontal offset 46 of 20 mm between the supply induction element 14 and the receiving induction element 24. A third series of measurements 122 in the right-hand diagram shows the course of the L22 of the receiving induction element 24 and the coupling factor as a function of the vertical distance 44 with a horizontal offset 46 of 40 mm between the supply induction element 14 and the receiving induction element 24.

[0087] As can be seen from the diagrams in Figure 5, the vertical distance 44 and the horizontal offset 46 each have a major influence on the self-inductances Lu, L22 of the supply induction element 14 and the receiving induction element 24, wherein the self-inductances Lu, L22 as parameters of the parameter set in turn influence the control of the supply unit 12 by the control and / or regulating unit 16 and the control can be carried out more precisely the more precisely the values ​​of the self-inductances L11, L22 used by the control and / or regulating unit 16 for control correspond to their actual values.

[0088] Using a correction factor, a corrected self-inductance of the supply induction element 14 can be determined using the following equation: where in equation (13) the expression Ln, m for the corrected self-inductance of the supply induction element 14, the expression fs tx stands for the correction factor and the term Lu stands for the self-inductance of the supply induction element 14, which is stored as an output value in the memory unit of the control and / or regulating unit 16 as a parameter of the parameter set.

[0089] Using a further correction factor, a corrected self-inductance of the pickup induction element 24 can be calculated using the following equation: where in equation (14) the expression l_22,m for the corrected self-inductance of the pickup inductance element 24, the expression f pn< stands for the further correction factor and the term L22 stands for the self-inductance of the receiving induction element 24, which is received by the control and / or regulating unit 16 as a parameter from the setting unit 18.

[0090] Figure 6 shows four schematic representations of possible arrangements between the supply induction element 14 of the supply unit 12 and the receiving induction element 24 of the receiving unit 22.

[0091] In an upper left illustration of Figure 6, a first case is shown in which the installation unit 18 is positioned on the installation plate 58 in such a way that no horizontal offset 46 is present. In an upper right illustration of Figure 6, a second case is shown in which the installation unit 18 is positioned on the installation plate 58 in such a way that a horizontal offset 46 is present, wherein the horizontal offset 46 in this case is 40 mm.

[0092] The control and / or regulating unit 16 is provided to use a vertical distance 62 between the supply induction element 14 and a top side 47 of the mounting plate 58. The vertical distance 62 is stored in the memory unit of the control and / or regulating unit 16. The two upper illustrations in Figure 6 each depict the case in which the mounting plate 58, as shown in Figure 1, is designed as a hob plate. In these cases, corresponding to the two upper illustrations in Figure 6, the vertical distance 62 between the supply induction element 14 and the top side 47 of the mounting plate 58 is 4 mm.

[0093] The parameter set includes a vertical distance 66 between the receiving induction element 24 and the top side 47 of the mounting plate 58. The vertical distance 66 is received by the control and / or regulating unit 16 from the mounting unit 18, wirelessly via the communication unit. In the present case, the vertical distance 66 between the receiving induction element 24 and the top side 47 of the mounting plate 58 has a value of 6 mm.

[0094] In two lower illustrations of Figure 6, a third case is shown at the bottom left and a fourth case at the bottom right, in each of which the supply induction element 14 has a greater vertical distance 62 from the top side 47 of the mounting plate 58. This vertical distance 44 is stored in the memory unit of the control and / or regulating unit 16 and is 24 mm for the third and fourth cases, respectively. The third and fourth cases could, for example, correspond to a situation in which the mounting plate 58 is designed not as a hob plate, but as a kitchen worktop.

[0095] In the operating state of the induction energy transmission system 10, the control and / or regulating unit 16 determines the vertical distance 44 from the sum of the vertical distances 62, 66, specifically for all four cases shown in Figure 6, wherein the vertical distance 44 is 10 mm in the first and second cases and 30 mm in the third and fourth cases.

[0096] In the lower left illustration of Figure 6, the mounting unit 18 is again positioned on the mounting plate 58 in such a way that no horizontal offset 46 is present. In the lower right illustration of Figure 6, the mounting unit 18 is again positioned on the mounting plate 58 in such a way that a horizontal offset 46 of 40 mm is present.

[0097] Below is a multivariable regression equation which the control and / or regulation unit 16 uses to determine the correction factor: where in the multivariable regression equation (15) the expression f pn< stands for the correction factor, the term e for Euler's number, and the term k for the coupling factor. The terms c?, Cs, and Cg each stand for a coefficient of the multivariable regression equation (15), which the control and / or regulating unit 16 determines from the parameter set or which are contained as concrete values ​​in the parameter set. Below is another multivariable regression equation, based on which the control and / or regulating unit 16 determines the further correction factor: where in the multivariable regression equation (16) the expression f stx represents the correction factor, the term k represents the coupling factor, and the term e represents Euler's number. The terms C4, Cs, and Ce each represent a coefficient of the multivariable regression equation (16), which the control and / or regulating unit 16 determines from the parameter set or which is contained as concrete values ​​in the parameter set.

[0098] The following is an equation (17) by means of which the control and / or regulating unit 16 determines an alignment between the supply induction element 14 and the receiving induction element 24, taking into account the horizontal offset 46 between the supply induction element 14 and the receiving induction element 24: where the term a represents the orientation, the term In represents the natural logarithm, the term k represents the coupling factor, and the term d represents the vertical distance 44 between the receiving induction element 24 and the supply induction element 14. The terms Ci, C2, and C3 each represent a coefficient of equation (17), which the control and / or regulating unit 16 determines from the parameter set or which are contained as concrete values ​​in the parameter set. The coefficients Ci, C2, C3, C4, C5, Ce, C7, Cs, and C9, as well as the vertical distance 44 (d), are constant parameters determined by the control and / or regulating unit 16, as follows:

[0099] The control and / or regulating unit 16 determines the coefficient Ci as follows: where in equation (18), the term C2 stands for the coefficient C2 and the term e stands for Euler's number. The term ki stands for the coupling factor and the term di for the distance 44 between the receiving induction element 24 and the supply induction element 14, where the index 1 stands for the first case shown in the top left of Figure 6. For each of the cases shown in Figure 6, a value for the coupling factor k is stored in the installation unit 18. This value was determined at the factory in standardized tests carried out under conditions corresponding to the cases shown in Figure 6. The control and / or regulating unit 16 receives these values ​​in the operating state of the induction energy transmission system 10 as components of the parameter set from the installation unit 18 and uses them to determine the coefficients Ci, C2, C3, C4, C5, Ce, C7, Cs and C9.

[0100] The coefficient C2 is determined by the control and / or regulating unit 16 using the following equation: where in equation (19), the term In represents the natural logarithm. The term k represents the coupling factor, and the term d represents the distance 44 between the receiving induction element 24 and the supply induction element 14. The index 1 represents the first case shown in the top left of Figure 6, and the index 3 represents the third case shown in the bottom left of Figure 6.

[0101] The coefficient C3 is determined by the control and / or regulating unit 16 using the following equation: (20) where in equation (20) the term C3 stands for the coefficient C3 and the term In in turn denotes the natural logarithm. The term a also stands for the orientation in equation (20), the term k in turn stands for the coupling factor and the term d in turn stands for the distance 44 between the receiving induction element 24 and the supply induction element 14, where the index 2 stands for the second case shown in the top right of Figure 6 and the index 4 stands for the fourth case shown in the bottom right of Figure 6. Based on the value for the vertical distance 62 stored in the memory unit, the control and / or regulating unit 16 determines whether the second or fourth case applies and selects the corresponding values ​​for the orientation, the coupling factor and the distance 44 from the parameter set to determine the coefficient c3.

[0102] The coefficient c4 is determined by the control and / or regulating unit 16 using the following equation: where in equation (21) the term C5 stands for the coefficient C5 and the term In in turn denotes the natural logarithm. The term f s In equation (21), tx represents the above-mentioned correction factor, and the expression k represents the coupling factor, where the index 1 represents the first case shown in the top left of Figure 6 and the index 3 represents the third case shown in the bottom left of Figure 6. Values ​​for the correction factor f stx for the four cases shown in Figure 6 are each included in the parameter set. Based on the value for the vertical distance 62 stored in the memory unit, the control and / or regulating unit 16 determines whether the first or the third case applies and selects the corresponding values ​​for the coupling factor and the correction factor from the parameter set to determine the coefficient c4.

[0103] The coefficients c5 and c8 are constant and each have the following

[0104] Value on: fife® = — (J, 1

[0105] The values ​​of these coefficients are stored in the parameter set.

[0106] The coefficient c6 is determined by the control and / or regulating unit 16 using the following equation: where in equation (23) the term c4 stands for the coefficient c4 and the term Cs stands for the coefficient Cs. The term In also denotes the natural logarithm in equation (23). The term f s In equation (23), tx stands for the above-mentioned correction factor, the term k in turn stands for the coupling factor, and the term a for the alignment, where the index 2 in turn stands for the second case shown in the top right of Figure 6, and the index 4 for the fourth case shown in the bottom right of Figure 6. Based on the value for the vertical distance 62 stored in the memory unit, the control and / or regulating unit 16 determines whether the second or fourth case applies and selects the corresponding values ​​for the alignment, the coupling factor, and the correction factor from the parameter set to determine the coefficient c8.

[0107] The coefficient c? is determined by the control and / or regulating unit 16 using the following equation (24): where in equation (24) the term c8 represents the coefficient c8 and the term In again represents the natural logarithm. The term f prxstands in equation (24) for the above-mentioned correction factor and the term k in turn stands for the coupling factor, where the index 1 in turn stands for the first case shown in the top left of Figure 6 and the index 3 for the third case shown in the bottom left of Figure 6. Values ​​for the correction factor for the four cases shown in Figure 6 are in turn each contained in the parameter set. Based on the value for the vertical distance 62 stored in the memory unit, the control and / or regulating unit 16 determines whether the first or the third case applies and selects the corresponding values ​​for the coupling factor and the correction factor from the parameter set to determine the coefficient c?.

[0108] The control and / or regulating unit 16 determines the coefficient Cg using the following equation: where in equation (25) the term c? again stands for the coefficient c? and the term Cs again stands for the coefficient c?. The term In here also denotes the natural logarithm. The term f pn< In equation (25), stands for the above-mentioned correction factor, the term k in turn stands for the coupling factor and the term a for the alignment, where the index 2 in turn stands for the second case shown in the top right of Figure 6 and the index 6 for the fourth case shown in the bottom right of Figure 3. Based on the value for the vertical distance 62 stored in the memory unit, the control and / or regulating unit 16 determines whether the second or the fourth case applies and selects the corresponding values ​​for the alignment, the coupling factor and the correction factor from the parameter set to determine the coefficient c9.

[0109] The control and / or regulation unit 16 can now calculate the corrected self-inductances of the supply inductance element 14 and the receiving inductance element using equations (13) and (14). It can also determine a corrected resistance for the electrical resistance 82 (load resistance) according to the following equation:

[0110] The control and / or regulating unit 16 is thus provided to calculate a corrected self-inductance of the supply induction element 14, a corrected self-inductance of the receiving induction element 24 and a corrected load resistance of the installation unit 18 by means of the coupling factor.

[0111] The control and / or regulation unit 16 is also provided to improve values ​​for the corrected self-inductance of the supply inductance element 14, the corrected self-inductance of the receiving inductance element 24, and the corrected load resistance of the mounting unit 18 by means of an iterative calculation method with multiple iteration steps. Here, the control and / or regulation unit 16 is provided to use the same values ​​measured at the measuring point 100. Furthermore, in each iteration step, the corrected self-inductance Ln, m of the supply induction element 14, the corrected self-inductance l_22,m of the receiving induction element 24 and the corrected load resistance Ri oa d,m of the mounting unit 18 in equations (11) to (17) for the self-inductance Lu of the supply induction element 14, for the self-inductance L22 of the receiving induction element and for the load resistance R| Oad the setup unit 18 to further improve the corrected variables determined thereby. This process is repeated several times. In this case, the control and / or regulation unit 16 is designed to perform four iteration steps, although a different number is also conceivable. With each iteration, the accuracy of the values ​​is improved.

[0112] With the values ​​now available, the power-frequency transfer function 98 shown as an example in Figure 8 can be calculated. The output power is given by:

[0113] In equation (27) Z eq for the equivalent impedance from equation (6) and the expression Re for the real part operator. The effective current h.rms provided by the inverter 2 results from the following equation:

[0114] The voltage provided by the inverter in first harmonic approximation is calculated in this case as follows:

[0115] Where D is the duty cycle of the inverter signal.

[0116] When calculating the power-frequency transfer function 98, the corrected values ​​for the self-inductance Ln, m of the supply induction element 14, for the self-inductance L22,m of the receiving induction element 24 and for the corrected load resistance Ri oa d,m of the installation unit 18. In addition, there is the measuring point 100.

[0117] The accuracy of the power-frequency transfer function 98 achieved here is already quite high, but can be further increased, in particular to account for other unknown tolerances such as manufacturing tolerances and measurement tolerances. The control and / or regulating unit 16 is therefore provided to consider at least one further measurement at a further measuring point when calculating the power-frequency transfer function 98 for the energy transfer between the supply unit 12 and the receiving unit 22, and to improve the power-frequency transfer function 98 by taking into account the further measurement at the further measuring point. This further measurement is also performed during a half-wave of the mains supply voltage.

[0118] For this purpose, the control and / or regulating unit 16 is provided to select a further frequency for the further measuring point, taking into account at least one power tolerance and the previously calculated power-frequency transfer function 98. The further frequency selected is a frequency at which, according to the power-frequency transfer function 98, the required power is delivered minus a tolerance amount. The tolerance amount could, for example, be the maximum power tolerance. If, for example, the required power is 2 kW and the worst-case power tolerance is 500 W, the further frequency selected would be the one that delivers a power of 1.5 kW according to the power-frequency transfer function 98. The control and / or regulating unit 16 is provided to perform the same previously described calculation steps for the measurement at the further measuring point as for the measurement at measuring point 100.In this case, one iteration could be omitted, or a different number of iteration steps could be chosen. This would further improve the corrected values ​​for the inductances and load resistance.

[0119] Subsequently, the power-frequency transfer function 98 is optimized. This takes into account the corrected parameters for the self-inductances and the load resistance calculated from the additional measurement point and / or the fact that there are now two measurement points 100 through which the power-frequency transfer function 98 must pass. Classic fitting methods, neural networks, and / or machine learning can be used for this purpose.

[0120] The control and / or regulation unit 16 is designed to select the point in the ZVS ("Zero Voltage Switching") switching range with the lowest losses as the operating point. The control and / or regulation unit 16 is designed to estimate the losses at the electronics and / or at the supply induction element 14 and / or at the receiving induction element 24 and to select a suitable operating point for operation of the installation unit 18 accordingly.

[0121] Figure 7 shows a flowchart of a method for operating the induction energy transmission system 10, which is carried out accordingly by the control and / or regulating unit 16. The supply unit 12 is controlled and / or regulated for energy transmission between the supply unit 12 and the receiving unit 22, wherein a power-frequency transfer function 98 for the energy transmission between the supply unit 12 and the receiving unit 22 is calculated based on at least one measurement at a measuring point 100, and at least one operating point for the energy transmission between the supply unit 12 and the receiving unit 22 is determined based on the calculated power-frequency transfer function 98.

[0122] The procedure starts after switching on the installation unit 18 with a step

[0123] 200. In this, as previously described, the measurement is carried out at the measuring point 100 to determine the equivalent impedance 40. In a step 210, using the measured equivalent impedance 40 and the known self-inductances Lu, L22 and the known load resistance Ri oa d as initial values ​​of the coupling factor k, the alignment a, the correction factors f s tx, f P r and finally the corrected self-inductances Ln, m , L22,m and the corrected load resistance Rioad, m are calculated. In an iterative calculation procedure, the corrected self-inductances and the corrected load resistance are further improved by using the corrected values ​​instead of the initial values ​​in the equations.

[0124] In a step 220, the power-frequency transfer function 98 is calculated as previously described.

[0125] In a step 230, a further measuring point is selected based on the calculated power-frequency transfer function 98, taking power tolerances into account.

[0126] In a step 240, a further measurement of the equivalent impedance 40 is carried out at the further measuring point.

[0127] In a step 250, the equivalent impedance 40 measured at the further measuring point and the previously calculated self-inductances Ln, m , L22,m and the known load resistance Ri oa d,m as initial values ​​of the coupling factor k, the alignment a, the correction factors fstx, f P rx and finally further corrected self-inductances Ln, m , L22,m and the corrected load resistance Ri oa d,m is calculated. In an iterative calculation procedure, the corrected self-inductances and the corrected load resistance can optionally be further improved.

[0128] In a step 260, the power-frequency transfer function 98 is optimized as previously described to obtain the final frequency transfer function 98.

[0129] In a step 270, a suitable operating point is selected based on the power-frequency transfer function 98, namely the one that provides the required power, lies in the ZVS switching range and is associated with the lowest losses.

[0130] In step 280, the supply induction element 14 is operated at the operating point. During operation, a continuous check is performed to determine whether the power consumption changes, which would indicate that an operating state has changed and / or that the mounting unit 18 has been moved. If the deviations exceed a defined limit, the process is repeated starting from step 250. Alternatively, the entire process could be repeated, particularly in the case of significant parameter changes, for example, if the mounting unit 18 has been moved.

[0131] Reference symbol

[0132] 10 Induction energy transfer system

[0133] 12 supply unit

[0134] 14 Supply induction element

[0135] 16 Control and / or regulation unit

[0136] 18 Installation unit

[0137] 20 installation unit

[0138] 22 Recording unit

[0139] 24 Recording induction element

[0140] 40 equivalent impedance

[0141] 44 vertical distance

[0142] 46 horizontal offset

[0143] 47 Top

[0144] 48 magnetic flux bundling element

[0145] 50 magnetic flux bundling element

[0146] 58 mounting plate

[0147] 60 induction hob

[0148] 62 vertical distance

[0149] 66 vertical distance

[0150] 72 small household appliances

[0151] 73 small household appliances

[0152] 74 compensation capacitor

[0153] 76 electrical resistance

[0154] 78 AC voltage source

[0155] 80 compensation capacitor

[0156] 82 electrical resistance

[0157] 84 Equivalent impedance

[0158] 86 equivalent impedance

[0159] 88 Equivalent impedance primary circuit

[0160] secondary circuit

[0161] ordinate

[0162] ordinate

[0163] abscissa

[0164] Power-frequency transfer function

[0165] measuring point

[0166] series of measurements

[0167] series of measurements

[0168] series of measurements

[0169] series of measurements

[0170] series of measurements

[0171] series of measurements

[0172] Step

[0173] Step

[0174] Step

[0175] Step

[0176] Step

[0177] Step

[0178] Step

[0179] Step

[0180] Step

Claims

Claims 1. Induction energy transmission system (10), in particular an induction cooking system, with a supply unit (12) which has at least one supply induction element (14) for inductively providing energy, with at least one installation unit (18, 20) which has at least one receiving unit (22) with at least one receiving induction element (24) for receiving the inductively provided energy, and with a control and / or regulating unit (16) for controlling and / or regulating the supply unit (12) for energy transmission between the supply unit (12) and the receiving unit (22), characterized in that the control and / or regulating unit (16) is provided toto calculate a power-frequency transfer function (98) for the energy transfer between the supply unit (12) and the receiving unit (22) based on at least one measurement at a measuring point (100) and to determine at least one operating point for the energy transfer between the supply unit (12) and the receiving unit (22) based on the calculated power-frequency transfer function (98).

2. Induction energy transmission system (10) according to claim 1, characterized in that the control and / or regulating unit (16) is provided to select such a high frequency for the measuring point (100) that a power consumption of the receiving induction element (24) during the energy transmission between the supply unit (12) and the receiving unit (22) is assuredly sufficiently low.

3. Induction energy transmission system (10) according to claim 1 or 2, characterized in that the control and / or regulating unit (16) is provided to calculate at least one coupling factor between the supply unit (12) and the receiving unit (22) based on the measurement at the measuring point (100).

4. Induction energy transmission system (10) according to claim 3, characterized in that the control and / or regulating unit (16) is provided to calculate a corrected self-inductance of the supply induction element (14), a corrected self-inductance of the receiving induction element (24) and / or a corrected load resistance of the installation unit (18, 20) by means of the coupling factor.

5. Induction energy transmission system (10) according to claim 4, characterized in that the control and / or regulating unit (16) is provided to improve values ​​for the corrected self-inductance of the supply inductance element (14), the corrected self-inductance of the receiving inductance element (24) and / or the corrected load resistance of the installation unit (18, 20) by means of an iterative calculation method with at least one iteration step.

6. Induction energy transmission system (10) according to claim 5, characterized in that the control and / or regulating unit (16) is provided to use the same values ​​measured at the measuring point (100) in each of the iteration steps.

7. Induction energy transmission system (10) according to claim 5 or 6, characterized in that the control and / or regulating unit (16) is provided to carry out at least 2 and at most 10 iteration steps.

8. Induction energy transmission system (10) according to one of the preceding claims, characterized in that the control and / or regulating unit (16) is provided to take into account at least one further measurement at a further measuring point when calculating the power-frequency transfer function (98) for the energy transmission between the supply unit (12) and the receiving unit (22).

9. Induction energy transmission system (10) according to claim 8, characterized in that the control and / or regulating unit (16) is provided to select a further frequency for the further measuring point, taking into account at least one power tolerance and the previously calculated power-frequency transfer function (98).

10. Induction energy transmission system (10) according to claim 8 or 9, characterized in that the control and / or regulating unit (16) is provided to improve the power-frequency transfer function (98) by taking into account the further measurement at the further measuring point.

11. Induction energy transmission system (10) according to one of claims 8 to 10, characterized in that the control and / or regulating unit (16) is provided to carry out the same calculation steps for the measurement at the further measuring point as for the measurement at the measuring point (100).

12. Induction energy transmission system (10) according to one of claims 8 to 11, characterized in that the control and / or regulating unit (16) is provided to select as the operating point the point in the ZVS switching range with the lowest losses.

13. Induction hob (60) of an induction energy transmission system (10) according to one of the preceding claims, characterized by the supply unit (12).

14. Small household appliance (72, 73) of an induction energy transmission system (10) according to one of claims 1 to 12, characterized by the installation unit (18, 20).

15. Method for operating an induction energy transmission system (10), in particular an induction cooking system, in particular according to one of claims 1 to 12, with a supply unit (12) which has at least one supply induction element (14) for an inductive provision of energy and with at least one installation unit (18, 20) which has at least one Receiving unit (22) with at least one receiving induction element (24) for receiving the inductively provided energy, wherein the supply unit (12) is controlled and / or regulated for energy transmission between the supply unit (12) and the receiving unit (22), characterized in that a power-frequency transfer function (98) for the energy transmission between the supply unit (12) and the receiving unit (22) is calculated based on at least one measurement at a measuring point (100), and at least one operating point for the energy transmission between the supply unit (12) and the receiving unit (22) is determined based on the calculated power-frequency transfer function (98).

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