CN116326205A - Oscillating unit, induction cooking appliance and method for operating an oscillating unit - Google Patents
Oscillating unit, induction cooking appliance and method for operating an oscillating unit Download PDFInfo
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- CN116326205A CN116326205A CN202180069241.XA CN202180069241A CN116326205A CN 116326205 A CN116326205 A CN 116326205A CN 202180069241 A CN202180069241 A CN 202180069241A CN 116326205 A CN116326205 A CN 116326205A
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Abstract
The invention relates to an oscillating unit, in particular an oscillating circuit (2), more particularly a quasi-resonant oscillating circuit, for generating heating power for an induction cooking appliance (1), in particular for a household induction cooking appliance and/or an induction hob, comprising: -a resonant tank (30), in particular a resonant circuit, for generating an electric and/or magnetic field and/or heating power, the resonant tank (30) being in particular connected to the first node (21); a switching element (35), in particular a single switching element, which is connected to the resonant tank (30), in particular via a first node (21), and which is driven with a switching signal for oscillating the resonant tank (30); a measuring unit (40) for measuring a first electrical parameter of the resonant tank (30), in particular for measuring a voltage (V) CE ) More particularly for measuring a firstNode voltage (V) of node (21) CE ) The method comprises the steps of carrying out a first treatment on the surface of the And an estimation unit (45) for estimating a second electrical parameter, in particular electrical power, of the resonant tank (30) based on the first electrical parameter, as well as an induction cooking appliance and a method for operating an oscillating unit.
Description
The invention relates to an oscillating unit, an induction cooking appliance and a method for operating an oscillating unit.
For induction cooking appliances, it is advantageous to control the electrical operation of induction cooking. However, in order to control the electrical operation, additional components are necessary.
It is an object of the present invention to provide an improved and preferably cost-effective and/or flexible oscillating unit, an induction cooking appliance and a method for operating an oscillating unit, which in particular allow an efficient and/or cost-effective and/or at least relatively accurate control of the electrical operation of induction cooking.
This object is solved in particular by an oscillating unit according to claim 1 and an induction cooking appliance according to claim 10 and a method according to claim 13. Improvements are provided in the dependent claims.
The invention relates to an oscillating unit, in particular an oscillating circuit, more particularly a quasi-resonant oscillating circuit, for generating heating power for an induction cooking appliance, in particular for a household induction cooking appliance and/or an induction hob, comprising:
a resonant tank, in particular a resonant circuit, for generating an electric and/or magnetic field and/or heating power, the resonant tank being in particular connected to a first node,
A switching element, in particular a single switching element, which is connected to the resonant tank, in particular via or at a first node, and which is driven with a switching signal for oscillating the resonant tank,
a measuring unit for measuring a first electrical parameter of the resonant tank, in particular for measuring a voltage of the resonant tank, more in particular for measuring a node voltage of or at the first node, and
an estimation unit for estimating a second electrical parameter of the resonance tank, in particular electrical power, based on the first electrical parameter.
The advantage in the proposed solution is in particular that the components required by the oscillating unit, in particular the measuring circuit, have or may have a smaller footprint and lower costs, since the measuring circuit for the measured parameter may essentially only comprise (taking as an example the measured voltage) a divider intended to scale the measured parameter to a voltage range that can be sensed by the control unit. On the other hand, as a further example, components required to measure the voltage and associated current on the shunt may require more costs and components, such as operational amplifiers and/or filters, for example.
In order to generate heating power for the induction cooking appliance, the resonant tank may receive in particular a supply voltage, more in particular a bus supply voltage at a third node compared to a ground voltage at the second node. In addition, the switching element oscillates the resonant tank, in particular by opening and closing a connection to a second node, in particular a ground node, with a predetermined switching parameter and/or a predetermined switching frequency. The predetermined switching frequency may particularly be in a frequency range between 10kHz and 50kHz, more particularly between 15kHz and 35kHz, more particularly between 20kHz and 30 kHz. By varying the switching frequency and/or the switching parameters and/or by interrupting the switching operation, in particular periodically, the power received by and/or transmitted from the resonant tank to the cooking vessel can be adjusted.
In a particular embodiment, the resonant tank includes at least a capacitive resonant element and an inductive resonant element. In particular, the capacitive resonator element and the inductive resonator element are connected at the first node and/or at the third node. In a particular embodiment, the resonant circuit comprises at least one capacitor and at least one inductor, in particular at least one inductor coil, as resonant elements.
In a particular embodiment, the inductive resonator element is used for generating energy for heating a cooking vessel, which is arranged in particular above the inductive resonator element. In a particular embodiment, the inductive resonator element comprises a resistor, so that damped oscillations are obtained.
In a particular embodiment, the capacitive resonant element and the inductive resonant element operate in parallel or in series.
The resonant tank may in particular be an LC circuit, a resonant circuit or a tank circuit. The resonant tank may in particular be a circuit consisting of an inductor and a capacitor connected together in parallel and/or in series. The resonant tank stores and transmits energy that oscillates at the resonant frequency of the circuit or tank.
The oscillation frequency of the resonant tank can be calculated in particular as 1/(2×pi×sqrt (l×c)), where L is the inductance of the resonant tank and C is the capacitance of the resonant tank. The inductance is defined by the internal parameters of the inductor, in particular the inductor coil, and the cooking vessel arranged on the inductor.
The heating energy in the cooking vessel arranged on the inductor is generated by eddy currents in the cooking vessel, which are caused by the magnetic field of the inductor.
In a particular embodiment, the switching unit is in particular switchably connected to the resonant tank and to the reference voltage node, in particular to the first node and to the second node, and/or comprises a switching element, in particular a transistor and/or a unidirectional element, in particular a diode, wherein in particular the transistor and/or the switching unit is an IGBT (insulated gate bipolar transistor), and/or wherein in particular the transistor and the diode are operated in parallel.
In a particular embodiment, the switching element is or can be switched between an open state and a closed state.
In a particular embodiment, in the closed state of the switching element, the resonant tank, in particular the capacitive resonant element and/or the inductive resonant element, is bidirectionally connected to the reference voltage node, the ground node and/or the second node.
In a particular embodiment, in the off-state of the switching element, the resonant tank, in particular the capacitive resonant element and/or the inductive resonant element, is at least partly floating and/or is only unidirectionally connected with the second node, in particular the ground node or the reference voltage node.
In a particular embodiment, the diode only allows current to flow from the second node to the first node.
In a particular embodiment, the transistors are bi-directionally connected such that current can flow in both directions, while the diodes are uni-directionally connected such that current can flow in only one direction. By using diodes, negative voltages within the resonant tank and/or the inductor can preferably be avoided.
The quasi-resonant tank circuit is in particular a tank circuit, wherein the tank circuit can be switchably connected to only one of the voltage nodes for excitation. In other words, preferably, there is only a single switching element that can connect the first node to a single voltage.
In a particular embodiment, the measuring unit comprises a voltage measuring unit for measuring a voltage of the first node, in particular compared to a voltage of the second node, as a measurement result or a first electrical parameter.
In a particular embodiment, the measurement unit comprises a dividing means for dividing the measurement result such that the measurement result does not exceed a predetermined evaluation range (in particular a range of 10V, preferably 5V).
In a particular embodiment, the measurement unit comprises a sampling unit that samples the measurement result or the division value of the first node using a predetermined sampling rate, wherein in particular the sampling rate is at least twice the resonance frequency of the resonance tank, more in particular at least five times the resonance frequency of the resonance tank, more in particular at least ten times the resonance frequency of the resonance tank.
In a particular embodiment, the estimation unit includes at least one of:
a deriving unit for deriving a derivative of the first electrical parameter based on the sampled first electrical parameter, in particular by applying a numerical derivative to the sampled first electrical parameter,
a multiplication unit for obtaining a multiplication result by multiplying the sampled first electrical parameter with a derivative of the first electrical parameter and in particular a constant factor, and
Averaging means for obtaining an average value of the multiplication result during a predetermined time, in particular during the off-time of the switching means.
The second electrical parameter is in particular the multiplication result or the average value.
In a particular embodiment, the estimation unit comprises a look-up table for obtaining the second electrical parameter based on the first electrical parameter.
In particular, the constant factor is the capacity of the capacitive resonator element. In particular, the second electrical parameter is the electrical power of the oscillating circuit.
In particular, the total electrical power may be obtained by multiplying the first electrical parameter and the third electrical parameter.
In particular, a weighted difference between the first electrical power and the second electrical parameter may be calculated to obtain the electrical power of the oscillating unit.
In particular, the estimation unit may take into account the current state of the switching element. In particular, the second electrical parameter can only be calculated when the switching element is in its off-state, in particular during its off-time. However, in the closed state, in particular during its on-time, no power can be measured, since the measured first parameter will be at least substantially zero.
The electrical power of the oscillating circuit is in particular the electrical power of the oscillating circuit that is consumed or received from a power supply connector supplied by a voltage supply unit, which in turn is supplied with electrical power by means of a mains input voltage and a mains input current. The electrical power of the oscillating circuit is in particular the electrical power of the oscillating circuit transmitted to the cooking vessel arranged on the inductive resonator element, in particular as heating power.
In a particular embodiment, the power supply measurement unit is connected with a power supply connector for receiving a power supply voltage, in particular with a bus power supply voltage at a third node, in particular compared to a ground voltage at the second node.
In a particular embodiment, the oscillating unit comprises a control unit for controlling the resonant tank by determining the switching parameter, in particular based on the second electrical parameter and/or the requested power, such that the power of the inductive resonant element is controlled in the control loop and/or in the closed loop.
In particular, the control unit comprises:
a power determination unit for determining the requested power based on the requested power level, an
A power control unit for controlling the power of the resonance tank based on the requested power/the requested power and the second electrical parameter.
In particular, the requested power is or may be a nominal value or a set point. In particular, the second electrical parameter is or may be an actual value of an indicator for an actual value of the control loop.
In particular, the control unit controls the resonant tank by adjusting at least one switching parameter, in particular the on-time and/or the off-time. In particular, the on-time defines how long the switch is in the closed state during a switching cycle, and the off-time defines how long the switch is in the open state during the same switching cycle.
In particular, the on-time is adjusted in order to control the resonance tank. In particular, for controlling the subsequent off-time, the resonant frequency of the resonant tank and the corresponding period are used, wherein the off-time is determined in particular based on the voltage at the switching element. In particular, the off-time is based on detecting a zero crossing of the voltage at the switching element.
The requested power is in particular determined and/or transmitted by the power requesting unit. The power requesting unit comprises in particular means (e.g. a knob or a touch sensitive unit, in particular a touch slider) for adjusting the requested power, so that the operator can request the appropriate power depending on his/her preference. In particular, the power requesting unit determines the power level, wherein the control unit comprises means for converting the power level into the requested power.
In order to supply the requested power to the cooking vessel, it is advantageous that the actual power of the oscillating unit can be estimated, so that by using a closed loop the power can be adjusted. This is advantageous because the actual power may vary based on the type, size and location of the cooking vessel. Advantageously, the power can be estimated by a single sensor, since in principle a current sensor and a voltage sensor would be necessary for estimating the present power.
The on-time may be at least 5 mus, in particular at least 10 mus. The on-time may be below 35 mus, in particular below 25ms. The on-time may vary, for example, between 10 and 25 mus.
The on-time may be at least 10 mus, in particular at least 20 mus. The on-time may be below 40 mus, in particular below 30ms. The off-time varies, for example, between 20 and 30 mus. The resonant frequency may be between 20kHz and 30 kHz.
In a particular embodiment, the first node is a switchable node and/or the second node is a ground node and/or the third node is a power node.
In particular, the node may be a node in a circuit. In particular, the node may be a voltage node in a circuit.
The sum of the currents flowing into the node may be considered to be equal to the sum of the currents flowing out of the node. The algebraic sum of the currents in the conductor network meeting at the node is zero. In addition, the voltage at or along the node is zero. Nodes may be partitioned in the drawing.
In the oscillating circuit according to the invention, the first node is connected to and/or connected to each of the resonant tank, the switching means and the measuring means.
In the oscillating circuit according to the invention, the second node is connected to and/or connects each of the capacitor, the switching means and the measuring means.
In the tank circuit according to the invention the third node is connected to and/or connects each of the power supply and the resonance tank.
The invention relates to an induction cooking appliance, in particular a household induction cooking appliance and/or an induction hob, comprising:
one, at least one, two, at least two, four, at least four, six or at least six oscillating circuits according to the invention,
-a user interface for requesting power for an oscillating circuit, in particular a quasi-resonant oscillating circuit, and
a voltage supply unit for supplying a voltage to the power supply connector of the oscillating circuit or circuits.
In an embodiment, the induction hob comprises four oscillating circuits, wherein each oscillating circuit comprises an inductor, and a user interface for requesting power from each of the inductors.
Household induction cooking appliances are in particular induction cooking appliances specifically designed for use in the home and/or for use in the home. Such devices have in particular significantly different requirements compared to professional cooking appliances, such as cost and/or availability and/or space requirements.
Household induction cooking appliances are or may not be specifically induction cooking appliances designed specifically for professional use (e.g., in canteen kitchens, restaurants, or generally for commercial cooking).
In particular, the voltage supply unit comprises a bridge rectifier, more particularly a diode, a bridge rectifier and/or a bus capacitor.
The voltage supply unit is supplied with power, in particular by means of a single-phase power supply only, which particularly means that the voltage supply unit is supplied with power by means of a phase connector and a neutral connector, which particularly supply power from an AC power supply with a frequency of about 50Hz to 60Hz and a voltage of about 100V to 240V.
In particular, the induction cooking appliance comprises a power supply measuring unit for measuring the/a third electrical parameter, in particular the input current of the voltage supply unit.
The invention relates to an oscillating unit, in particular an oscillating circuit, more particularly a quasi-resonant oscillating circuit, for generating heating power for an induction cooking appliance, in particular for a household induction cooking appliance and/or an induction hob, comprising a resonant tank, in particular a resonant circuit, for generating an electric and/or magnetic field and/or heating power.
The heating power generated by such an oscillating unit may be configured in particular to heat the heating zone.
The induction cooking appliance of the present invention may in particular be configured such that in at least one mode of operation one or more heating zones form a cooking zone and/or combine into one cooking zone, respectively. The cooking zone may in particular be provided as at least a part of the cooking surface. In particular, such cooking zone is associated with at least one heating zone. Additionally or alternatively, a cooking zone may be associated with more than one heating zone. In particular, a cooking zone may be associated with an even number, in particular two, four, six, eight or ten, more in particular two heating zones. Alternatively, the cooking zone may be associated with an odd number, in particular three, five, seven or nine, more in particular three heating zones.
Preferably, the induction cooking appliance of the present invention is configured such that the cooking zone comprises one or more heating zones, which may be driven at the same or different power, frequency or heating level.
In the present invention, it is preferred that in at least one mode of operation of the induction cooking appliance according to the present invention is configured such that the cooking zone comprises at least two, preferably two heating zones, which are driven by the same power, frequency or heating level. In particular, such cooking zone comprises or is associated with at least two, preferably two, heating power transfer elements.
Additionally or alternatively, the induction cooking appliance of the present invention may be configured such that the number of heating zones associated with one cooking zone may vary and/or may be adjustable depending on the needs of the cooking and/or the size, form or kind of cookware placed on the cooking surface.
The invention further relates to a method for operating an oscillating unit, in particular an oscillating unit according to the invention, in particular a quasi-resonant oscillating circuit, for generating heating power for an induction cooking appliance, in particular for a household induction cooking appliance and/or an induction cooker, the method comprising:
generating an electric and/or magnetic field and/or heating power by a resonant tank, in particular a resonant circuit, which is in particular connected to the first node,
driving a switching element, in particular a single switching element, with a switching signal for oscillating the resonant tank, which is connected in particular via a first node to the resonant tank,
measuring a first electrical parameter of the oscillating circuit, in particular the voltage of the first node (or node voltage), by a measuring unit, and
-estimating, by an estimation unit, a second electrical parameter, in particular an electrical power, of the oscillating circuit based on the first electrical parameter.
In a particular embodiment, the method for operating an oscillating unit further comprises, in particular by the estimating unit:
obtaining, by the deriving unit, a derivative of the first electrical parameter based on the sampled first electrical parameter, in particular by applying a numerical differentiation to the sampled first electrical parameter, and/or
-obtaining a multiplication result by a multiplication unit by multiplying the sampled first electrical parameter with a derivative of the first electrical parameter, in particular a constant factor, and/or
-obtaining, by the averaging device, an average value of the multiplication result during a predetermined time, in particular during the off-time of the switching device.
In a particular embodiment, the method for operating an oscillating unit comprises, in particular by the estimating unit:
deriving the first electrical parameter based on the sampled first electrical parameter by a deriving unit to obtain a derivative, in particular by applying a numerical differentiation to the sampled first electrical parameter, and/or
-multiplying the sampled first electrical parameter by a derivative of the first electrical parameter, in particular a constant factor, by a multiplication unit to obtain a multiplication result, and/or
-averaging the multiplication result by the averaging device over a predetermined time, in particular during the off-time of the switching device, to obtain an average value, and/or
-multiplying the first electrical parameter and the third electrical parameter to obtain a total electrical power, and/or
-calculating a weighted difference between the total electrical power and the second electrical parameter.
In particular, the second electrical parameter is or may be a multiplication result or an average value.
In particular, the look-up table may obtain the second electrical parameter based on the first electrical parameter.
In particular, the constant factor is or may be the capacitance of the capacitive resonator element. In particular, the second electrical parameter is or may be the electrical power of the oscillating circuit.
In particular, the first electrical power is or may be obtained by multiplying the first electrical parameter and the third electrical parameter and/or by a weighted difference between the first electrical power and the second electrical parameter.
In a particular embodiment, the method for operating an oscillating unit further comprises: the resonant tank is controlled by the control unit by determining the switching parameter, in particular based on the second electrical parameter and/or the requested power, such that the power of the inductive resonant element is controlled in the control loop and/or in the closed loop.
In a particular embodiment, the control unit comprises determining, by the power determining unit, the requested power based on the requested power level, and/or controlling, by the power control unit, the power of the resonant tank based on the requested power/the requested power and the second electrical parameter.
In particular, the requested power is or may be a nominal value or a set point, and wherein the second electrical parameter is an actual value of the control loop.
In particular, the oscillating unit is controlled by adjusting at least one switching parameter, in particular the on-time and/or the off-time. The on-time preferably defines how long the switch is in the closed state during a switching cycle and the off-time defines how long the switch is in the open state during the same switching cycle.
In particular, for controlling the resonance tank, the on-time is adjusted, and/or in particular for controlling the subsequent off-time, the resonance frequency of the resonance tank and the corresponding period are used. The off-time is preferably determined based on the voltage at the switching element and/or in particular based on detecting a zero crossing of the voltage at the switching element.
The invention will be described in further detail with reference to the accompanying drawings, in which:
figure 1 shows an oscillating unit according to an embodiment of the invention,
fig. 2 illustrates an induction cooking appliance according to an embodiment of the present invention, and
fig. 3 illustrates an induction cooking appliance according to an embodiment of the present invention.
Fig. 1 shows a quasi-resonant oscillating circuit 2 for generating heating power for an induction cooking appliance 1, for a household induction cooking appliance as an induction hob.
The oscillating unit 2 comprises a resonant tank 30 as a resonant circuit for generating an electric and/or magnetic field and a corresponding heating power for a not shown cooking vessel arranged on the oscillating unit 2. The resonance tank 30 is connected to the first node 21 of the oscillating unit 2.
The oscillating unit 2 comprises a single switching element 35 connected to the resonance tank 30 via a first node 21. The oscillating unit is driven by a switching signal for oscillating the resonant tank 30.
The oscillating unit 2 comprises a measuring unit 40 forFor measuring a first electrical parameter of the resonant tank 30, in particular for measuring the node voltage V at the first node 21 and/or across the switching element 35 CE 。
The oscillating unit 2 comprises an estimating unit 45 for estimating a second electrical parameter of the resonance tank 30, in particular an electrical power or an indicator of electrical power, based on the first electrical parameter.
To generate heating power for the induction cooking appliance, resonant tank 30 receives a supply voltage, in particular in comparison with ground voltage V at second node 22 GND Is connected to the bus supply voltage V at the third node 23 Bus line . The resonant tank 30 is connected to the first node 21 and the third node 23.
In addition, the switching element 35 oscillates the resonant tank by opening and closing at a predetermined switching parameter and/or a predetermined switching frequency. The predetermined switching frequency may particularly be in a frequency range between 10kHz and 50kHz, more particularly between 15kHz and 35kHz, more particularly between 20kHz and 30kHz or between 25kHz and 30 kHz.
By varying the switching frequency and/or the switching parameters, the power received and/or transmitted by the resonant tank may be adjusted. Additionally or alternatively, by periodically interrupting the switching operation, the power received and/or transmitted by the resonant tank may be adjusted.
The resonant tank 30 includes at least a capacitive resonant element 31 and an inductive resonant element 32. The capacitive resonator element 31 and the inductive resonator element 32 are connected at the first node 21 and at the third node 23.
The resonant circuit comprises a capacitor 31 and an inductor 32, in particular at least one inductor 32, as resonant elements. The inductive resonator element 32 is used to generate energy for heating a cooking vessel, not shown.
The inductive resonator element 32 comprises a resistor 33 so as to obtain damped oscillations. The capacitive resonator element 31 and the inductive resonator element 32 operate in parallel, but it is also possible to operate in series.
The inductive resonator element 32 is in a circuit represented by an inductive element 34 in series with a resistive element 33. Alternatively, the inductive resonating element 32 may be in a circuit represented by an inductive element in parallel with a resistive element.
In a particular not shown embodiment, it is also possible that the resonant tank 30 is constituted by two or more resonant tanks 30 operating in parallel, which are alternately activated by a double sided toggle switch.
The resonant tank may be an LC circuit, a resonant circuit, a tank circuit, or a tuning circuit. The resonant tank may be a circuit comprised of an inductor and a capacitor connected together in parallel and/or in series. The resonant tank stores and transmits energy that oscillates at the resonant frequency of the circuit or tank.
The oscillation frequency of the resonant tank can be calculated as 1/(2×pi×sqrt (l×c)), where L is the inductance of the resonant tank and C is the capacitance of the resonant tank. The inductance is defined by the internal and/or external parameters of the inductor, in particular the inductor coil itself and the cooking vessel arranged on the inductor. The heating energy in the cooking vessel is generated by eddy currents, which are caused by the magnetic field of the inductor in the cooking vessel.
The switching unit 35 switchably connects the resonance tank 30 and the reference voltage node (the first node 21 and the second node 22 in fig. 1). The switching unit 35 comprises a switching element 35, in particular a transistor 36, and a unidirectional element, in particular a diode 37. In the embodiment, the transistor 36 is an IGBT (insulated gate bipolar transistor), and the transistor 36 and the diode 37 operate in parallel.
The switching element 35 is switchable between an open state and a closed state and is switchable.
In the closed state of the switching element 35, the resonance tank formed by the capacitive resonance element 31 and the inductive resonance element 32 is connected bi-directionally to the reference voltage node or the second node 22.
In the off-state of the switching element 35, the resonance tank (capacitive resonance element 31 and inductive resonance element 32 in fig. 1) is at least partly floating and is only connected unidirectionally with the second node 22. Diode 37 only allows current to flow from second node 22 to first node 21.
The transistor 36 realizes a bi-directional connection so that current can flow in both directions, while the diode 37 realizes only a unidirectional connection so that current can flow in only one direction. By using a diode, a negative voltage within the inductor can be avoided.
A quasi-resonant tank circuit is a tank circuit in which the tank circuit may be switchably connected to only one of the voltage nodes for excitation. In other words, in fig. 1, there is only one voltage V that can connect the first node 21 to only a single voltage V GND Is provided.
The measurement unit 40 comprises a voltage measurement device 41 for measuring the voltage of the first node 21 compared to the second node 22 as a measurement result or a first electrical parameter.
The measurement unit 40 comprises a dividing means 42 for dividing the measurement result such that the measurement result does not exceed a predetermined evaluation range.
The measurement unit 40 comprises a sampling unit 43 that samples the measurement result or the division value of the first node 21 using a predetermined sampling rate. The sampling unit may be accompanied by a filter unit, in particular to filter out high frequencies from the signal received from the dividing device 42 or the measuring device 41.
In an embodiment, the sampling rate is at least twice the resonance frequency of the resonance tank, in particular at least five times the resonance frequency of the resonance tank, more in particular at least ten times the resonance frequency of the resonance tank.
The estimation unit 45 comprises a derivation unit 47 for deriving a derivative of the first electrical parameter based on the sampled first electrical parameter, in an embodiment by applying a numerical derivative to the sampled first electrical parameter.
The estimation unit 45 further comprises a multiplication unit 46 for obtaining a multiplication result by multiplying the sampled first electrical parameter with a derivative of the first electrical parameter, in particular a constant factor.
The estimation unit 45 further comprises averaging means 48 for obtaining an average value of the multiplication result during the off-time of the switching means 35 within a predetermined time.
The second electrical parameter is the multiplication result or the average value. The second electrical parameter may also be obtained by a look-up table for obtaining the second electrical parameter based on the first electrical parameter.
The constant factor is the capacitance C of the capacitive resonator element 31. In an embodiment, the second electrical parameter is the electrical power of the oscillating circuit.
The second electrical parameter is obtained based on the first electrical power by multiplying the first electrical parameter and the third electrical parameter and/or by based on a weighted difference between the first electrical power and the second electrical parameter.
The estimation unit 45 also takes into account the current state of the switching element 35. In an embodiment, the second electrical parameter is calculated only when the switching element 35 is in the off-state and thus during its off-time. However, in the closed state, during its on-time, no power can be measured, since the measured first parameter will be at least substantially zero.
The electrical power of the oscillating circuit is in particular the electrical power consumed by the oscillating circuit or received from the power supply connector. The electric power of the oscillating circuit is in particular the electric power of the oscillating circuit transmitted to the cooking vessel arranged on the inductive resonator element.
The oscillating unit comprises power connectors 22, 23 for receiving a ground voltage V, in particular compared to the ground voltage V at the second node 22 GND Is connected to the bus supply voltage V at the third node 23 Bus line 。
The oscillating unit 2 comprises a control unit 50 for controlling the resonant tank 30 by determining a switching parameter based on the second electrical parameter and the requested power, such that the power of the inductive resonant element is controlled in the control loop and/or in the closed loop, respectively.
The control unit 50 comprises a power determination unit 51 for determining the requested power based on the requested power level.
The control unit 50 comprises a power control unit 52 for controlling the power of the resonance tank 30 based on the requested power and the second electrical parameter.
In the control loop, the requested power corresponds to a nominal or set value and the second electrical parameter corresponds to an actual value of the control loop.
The control unit 50 performs power control by adjusting at least one switching parameter, in particular the on-time and/or the off-time. The on-time defines how long the switch is in the closed state during a switching cycle and the off-time defines how long the switch is in the open state during the same switching cycle.
To control the resonant tank 30, the on-time is adjusted. In order to control the subsequent off-time, the resonant frequency of the resonant tank 30 and the corresponding period are used, while the off-time is determined based on the voltage at the switching element. In particular, the off-time is based on detecting a zero crossing of the voltage at the switching element.
The requested power is in particular determined and/or transmitted by the power requesting unit. The power requesting unit comprises in particular means (e.g. a knob) for adjusting the requested power, so that the operator can request an appropriate power depending on his preferences. The power requesting unit determines a power level, wherein the control unit 50 comprises means for converting the power level into the requested power.
In order to supply the requested power to the cooking vessel, it is advantageous that the actual power can be estimated such that by using a closed loop the power can be adjusted. This is advantageous because the actual power may vary based on the type, size and location of the cooking vessel. Advantageously, the power can be estimated by a single sensor, since in principle a current sensor and a voltage sensor would be necessary for estimating the present power.
The on-time may be at least 5 mus, in particular at least 10 mus. The on-time may be below 35 mus, in particular below 25ms. The on-time may vary between 10 mus and 25 mus.
The off-time may be at least 10 mus, in particular at least 20 mus. The off-time may be below 40 mus, in particular below 30ms. The off-time varies between 20 and 30 mus.
The resonant frequency may be between 20kHz and 30 kHz.
The first node 21 is a switchable node and/or the second node 22 is a ground node and/or the third node 23 is a power node.
The node according to the invention may in particular be a connection point at or through which at least two different components, devices or units are electrically connected. In particular, this may be a set of electrical connection lines, so that they have the same voltage or potential.
In particular, the node may be a node in a circuit. In particular, the node may be a voltage node in a circuit.
The sum of the currents flowing into the node may be considered to be equal to the sum of the currents flowing out of the node. The algebraic sum of the currents in the conductor network meeting at the node is zero. In addition, the voltage at or along the node is zero.
In the oscillating circuit 2 according to the invention, the first node 21 is connected to each of the resonant tank, the switching means and the measuring means.
In the oscillating circuit 2 according to the invention, the second node 22 is connected to each of the capacitor, the switching means and the measuring means.
In the oscillating circuit 2 according to the invention, the third node 23 is connected to each of the power supply and the resonance tank.
Fig. 2 and 3 show an induction cooking appliance 1, in particular a household induction cooking appliance and/or an induction hob, comprising one, at least one, two, at least two, four, at least four, six or at least six oscillating circuits.
The induction cooking appliance 1 comprises a user interface 60 for requesting power for the quasi-resonant oscillating circuit.
The induction cooking appliance 1 includes a voltage supply unit 10 for supplying a voltage to a power connector of the oscillating circuit.
In an embodiment, the induction hob 1 comprises four oscillating circuits, each comprising an inductor, and a user interface 60 for requesting power from each of these inductors.
Household induction cooking appliances are in particular induction cooking appliances specifically designed for use in the home and/or for use in the home. Such devices have significantly different requirements, such as cost and/or availability and/or space requirements, compared to professional cooking appliances. Household induction cooking appliances are not specifically induction cooking appliances specifically designed for professional use (e.g., in canteen kitchens, restaurants, or generally for commercial cooking).
The voltage supply unit 10 comprises a bridge rectifier and/or a bus capacitor 11.
The voltage supply unit 10 is supplied with power, in particular by means of a single-phase power supply only, which means in particular that the voltage supply unit 10 is supplied with power by means of a phase connector and a neutral connector, in particular from an AC power supply with a frequency of about 50Hz to 60Hz and a voltage of about 100V to 240V.
The induction cooking appliance 1 comprises a power supply measuring unit 55 for measuring a third electrical parameter, in particular an input current of the voltage supply unit 10.
As an example, fig. 3 shows four oscillating units 2 according to the invention, wherein a first power supply 10 supplies power from a first voltage phase to two oscillating units 2 by means of a first DC bus. The second power supply 10 supplies power from the second voltage phase to the two oscillating units 2 by means of a second DC bus.
In a more general method, the first power supply 10 supplies power from a first voltage phase to at least two oscillating units 2, for example by means of a first DC bus. The second power supply 10 supplies power from the second voltage phase to the at least two oscillating units 2, for example by means of a second DC bus.
The circuit shown thus provides a method for operating an oscillating circuit 2, in particular a quasi-resonant oscillating circuit, for generating heating power for an induction cooking appliance 1, in particular for a household induction cooking appliance and/or induction cooker, comprising: a resonant tank 30, in particular a resonant circuit, for generating heating power, the resonant tank being connected to the first node 21; and a switching element 35, in particular a single switching element, which is connected to the first node 21 and is driven with a switching frequency for oscillating the resonant tank 30.
The method for operating the oscillating circuit 2 comprises:
measuring a first electrical parameter of the oscillating circuit 2 by the measuring unit 40 for measuring a voltage node voltage V of the first node 21 CE And (b)
The second electrical parameter of the oscillating circuit 2, which is the electrical power, is estimated by the estimation unit 45 based on the first electrical parameter.
In order to operate the oscillation, in the estimation unit, the derivation unit 47 obtains a derivative of the first electrical parameter based on the sampled first electrical parameter, in particular by applying a numerical derivative to the sampled first electrical parameter.
The multiplication unit 46 obtains the multiplication result by multiplying the sampled first electrical parameter with a derivative of the first electrical parameter, in particular a constant factor.
The averaging means 48 obtains an average value of the multiplication result during a predetermined time, in particular during the off-time of the switching means.
In an embodiment, the second electrical parameter is a multiplication result or an average value.
Alternatively or additionally, the lookup table may obtain the second electrical parameter based on the first electrical parameter.
In an embodiment, the constant factor is or may be the capacitance of the capacitive resonant element. In particular, the second electrical parameter is the electrical power of the oscillating circuit.
In an embodiment, the first electrical power may also be obtained by multiplying the first electrical parameter and the third electrical parameter and/or by a weighted difference between the first electrical power and the second electrical parameter.
In a method for operating an oscillating unit, the control unit 50 controls the resonant tank by determining the switching parameter, in particular based on the second electrical parameter and the requested power, such that the power of the inductive resonant element is controlled in the control loop and/or in the closed loop.
In an embodiment, the control unit comprises:
determining, by the power determining unit 51, the requested power based on the requested power level, and
control of the power of the resonance tank by the power control unit 52 based on the requested power/the requested power and the second electrical parameter.
In an embodiment, the requested power is a nominal value or a set point, and wherein the second electrical parameter is an actual value of the control loop.
In particular, the oscillating unit 2 is controlled by adjusting at least one switching parameter, in particular the on-time and/or the off-time. The on-time preferably defines how long the switch is in the closed state during a switching cycle and the off-time defines how long the switch is in the open state during the same switching cycle.
In an embodiment, the on-time is adjusted in order to control the resonance tank 30. For controlling the subsequent turn-off time, the resonance frequency of the resonance tank and the corresponding period are used or can be used. The off-time is preferably determined based on the voltage at the switching element. In particular, the off-time is or may be based on detecting a zero crossing of the voltage at the switching element 35.
Quasi-resonant tank 2 (which may also be referred to as an induction generator) is based on a circuit having two phases (T as on-time Switch on And T as off time Shut off ) To generate power.
At T Switch on During the phase, the IGBT as the switching unit 35 is closed and a current flows through it, thereby accumulating power in the inductor 32. Voltage V CE Short to ground 22 and therefore has a value of 0.
In contrast, at T Shut off During this phase, the IGBT 35 is turned off, so that the current and voltage resonate in the tank 2. Voltage V on IGBT CE Sinusoidal behavior including attenuation:
-V CE ＝V into (I) *exp(-αt)*sin(ωt+φ Into (I) ),
Wherein V is Into (I) Is the input voltage of the rectified mains signal, ω is the angular frequency, t is the time, and
is the input angle of the rectified mains signal.
By means of a voltage V across a switching element CE A control or estimation unit (e.g., CPU) may recombine the shape of the sinusoidal decay. From the latter, useful information can be gathered, such as maximum peak, minimum peak, period or decay factor.
Because at T Shut off The voltage during the phase is directly related to the current by the relation i=c dv/dt, so the feature also carries information about the current, since the capacitance C is fixed.
Concerning T Switch on Information of the current during the phase is also encoded at V CE In the shape of (2) because of T Shut off The initial conditions of the phase define the parameter V Into (I) And
in addition, T Switch on The value is known because it is determined by the driving algorithm. Thus, by taking the shape of the voltage Vce, the relevant T can be obtained Switch on And T Shut off Information of the current in the two phases.
Having established this framework, different embodiments of the present disclosure may calculate power in different ways depending on the particular requirements. For example, the look-up table approach may have the benefit of avoiding heavy computation, but may be cumbersome from a memory perspective; on the other hand, equation solving techniques limit memory usage, but may require computational power.
Input current I Mains supply The optional presence of (c) may be exploited in particular to enhance the robustness of the power estimate. If only one resonant tank, in particular a generator, is running, the final power value can be obtained as the voltage V from the sampling CE And from the input current I Mains supply Weighted averages between the estimates of (c). By means of the test, the weights can be selected according to the robustness of the evaluation of each estimate.
Otherwise, if more than one resonant tank, in particular a generator, is running, it is still possible to use a current I as a function of the input current Mains supply And calculating the total power estimated value. For example, if the sampled voltage V CE The sum of the obtained power estimates exceeds the input current I Mains supply A predetermined value (e.g., 10%) and the robustness of both estimates has been verified to be equal, such that at the sampled voltage V CE And input current I Mains supply The same weight has been selected, the power estimate for each generator may be modified by a predetermined value, e.g., such as 5% of 10%/2, where 2 may be selected because the weights are the same.
List of reference numerals
1. Induction cooker
2. Oscillating circuit
10. Voltage supply unit
11. Bus capacitor
21. First node
22. Second node
23. Third node
30. Resonant tank
31. Capacitive resonant element
32-34 inductive resonator element
35-37 switch element
40-43 measuring unit
41. Voltage measuring device
42. Division device
43. Sampling unit
45-49 estimation unit
46 49 multiplication unit
47. Deriving unit
48. Averaging device
50. Control unit
51. Power determination unit
52. Power control unit
55. Measuring unit
60. User interface
I Mains supply Mains supply current
V Bus line Supply voltage
V CE Voltage across a switching element
V GND Ground voltage
V Mains supply Mains voltage
Claims (15)
1. Oscillation unit, in particular an oscillation circuit (2), more in particular a quasi-resonant oscillation circuit, for generating heating power for an induction cooking appliance (1), in particular for a household induction cooking appliance and/or an induction hob, comprising:
-a resonant tank (30), in particular a resonant circuit, for generating an electric and/or magnetic field and/or heating power, the resonant tank (30) being in particular connected to a first node (21),
a switching element (35), in particular a single switching element, which is connected to the resonant tank (30), in particular via the first node (21), and which is driven with a switching signal for oscillating the resonant tank (30),
-a measuring unit (40) for measuring a first electrical parameter of the resonant tank (30), in particular for measuring 
Voltage (V) CE ) More particularly for measuring the node voltage (V) of the first node (21) CE ) And (b)
-an estimation unit (45) for estimating a second electrical parameter, in particular electrical power, of the resonant tank (30) based on the first electrical parameter.
2. The oscillation unit according to claim 1,
wherein the resonant tank (30) comprises at least a capacitive resonant element (31) and an inductive resonant element (32, 33), which are connected in particular at the first node (21) and/or at a third node (23),
in particular, wherein the resonant circuit comprises at least one capacitor (31) and at least one inductor (32), in particular at least one inductor coil (32), as resonant elements,
in particular, the inductive resonator element (32) is used for generating energy for heating a cooking vessel.
3. The oscillating unit of claim 1 and/or 2,
wherein the inductive resonator element (32) comprises a resistor (33) so as to obtain damped oscillations,
in particular, wherein the capacitive resonator element (31) and the inductive resonator element (32) are operated in parallel or in series.
4. An oscillating unit according to any preceding claim,
Wherein the switching unit (35) is in particular switchably connected to the resonant tank (30) and to a reference voltage node, in particular to the first node (21) and to the second node (22), and/or comprises a switching element (35), in particular a transistor (36), and/or a unidirectional element, in particular a diode (37), wherein in particular the switching element (35) is an IGBT (insulated gate bipolar transistor), and/or wherein in particular the transistor (36) and the diode (37) are operated in parallel, and/or
Wherein the switching element (35) is switchable between an open state and a closed state, and/or
Wherein in the closed state of the switching element (35), the resonant tank, in particular the capacitive resonant element (31) and/or the inductive resonant element (32, 33), is connected in both directions to the reference voltage node or to the second node (22), and/or
Wherein in the open state of the switching element (35), the resonant tank, in particular the capacitive resonant element (31) and/or the inductive resonant element (32, 33), is at least partially floating, is connected only unidirectionally to the second node (22), and/or
Wherein the diode (37) only allows current to flow from the second node (22) to the first node (21).
5. An oscillating unit according to any preceding claim,
wherein the measuring unit (40) comprises:
a voltage measuring unit (41) for measuring the voltage of the first node (21), in particular compared to the voltage of the second node (22), as a measurement result or a first electrical parameter, and/or
Dividing means (42) for dividing the measurements so that, in particular, the measurements do not exceed a predetermined evaluation range, and/or
-a sampling unit (43) for sampling the measurement result or the division values of the first node (21) using a predetermined sampling rate, wherein in particular the sampling rate is at least twice the resonance frequency of the resonance tank, more in particular at least five times the resonance frequency of the resonance tank, more in particular at least ten times the resonance frequency of the resonance tank.
6. An oscillating unit according to any preceding claim,
wherein the estimation unit (45) comprises:
-a deriving unit (47) for deriving a derivative of the first electrical parameter based on the sampled first electrical parameter, in particular by applying a numerical derivative to the sampled first electrical parameter, and/or
-a multiplication unit (46) for obtaining a multiplication result by multiplying the sampled first electrical parameter with a derivative of the first electrical parameter and in particular a constant factor, and/or
-averaging means (48) for obtaining an average of the multiplication results within a predetermined time, in particular during an off-time of the switching means (35), and/or
-a multiplication unit (49) for obtaining a total electric power by multiplying the first electric parameter and the third electric parameter, and/or
A weighting unit for obtaining a weighted difference between the total electric power and the second electric parameter, and/or
A look-up table for obtaining the second electrical parameter based on the first electrical parameter,
-wherein, in particular, the constant factor is the capacitance (C) of the capacitive resonator element (31), and/or
-wherein the second electrical parameter is the multiplication result or the average value, and/or
-wherein in particular the second electrical parameter is the electrical power of the oscillating circuit.
7. The oscillating unit according to any one of the preceding claims, comprising a power supply connector (22, 23) for receiving a power supply voltage, in particular a ground voltage (V), in particular compared to a ground voltage (V) at the second node (22) GND ) Is connected to the bus supply voltage (V) at a third node (23) Bus line )。
8. An oscillating unit according to any preceding claim,
comprising a control unit (50) for controlling the resonant tank (30) by determining a switching parameter, in particular based on the second electrical parameter and/or the requested power, such that the power of the inductive resonant element is controlled in a control loop and/or in a closed loop,
Wherein in particular the control unit (50) comprises:
-a power determination unit (51) for determining the requested power based on the requested power level, and/or
A power control unit (52) for controlling the power of the resonance tank (30) based on the requested power/the requested power and the second electrical parameter,
the control of the power is in particular carried out by adjusting at least one switching parameter, in particular the on-time and/or the off-time,
-wherein, in particular, for controlling the resonant tank (30), the on-time of the switching element (35) is adjusted, and/or
-wherein, in particular, for controlling the subsequent turn-off time, the resonance frequency and the corresponding period of the resonance tank (30) are determined, and/or
Wherein, in particular, the off-time is preferably determined based on the voltage at the switching element, and/or
Wherein, in particular, the off-time is based on detecting a zero crossing of the voltage at the switching element,
-wherein in particular the on-time defines how long the switching element is in the closed state during a switching cycle and the off-time defines how long the switching element is in the open state during the same switching cycle, and/or
-wherein in particular the requested power is a nominal value or a set point of the control loop, and wherein the second electrical parameter is an actual value of the control loop.
9. An oscillating unit according to any preceding claim,
wherein the first node (21) is a switchable node, and/or wherein the second node (22) is a ground node, and/or wherein the third node (23) is a power supply node.
10. Induction cooking appliance, in particular a household induction cooking appliance and/or an induction hob, comprising:
one, at least one, two, at least two, four, at least four, six or at least six oscillating circuits according to any one of claims 1 to 9,
-a user interface (60) for requesting power for the quasi-resonant tank circuit, and/or
-at least one voltage supply unit (10) for supplying a voltage to the power supply connector (23, 22) of the oscillating circuit(s) (2).
11. The induction cooking appliance of claim 10,
wherein the at least one voltage supply unit (10) comprises a bridge rectifier and/or a bus capacitor (11).
12. The induction cooking appliance of any one of claims 10 or 11, comprising:
-a power supply measurement unit (55) for measuring the third electrical parameter, in particular the input current (I) of the voltage supply unit (10) Mains supply )。
13. Method for operating an oscillating unit (2), in particular an oscillating unit according to any one of claims 1 to 9, in particular a quasi-resonant oscillating circuit, for generating heating power for an induction cooking appliance (1), in particular for a household induction cooking appliance and/or an induction hob, the method comprising:
generating an electric and/or magnetic field and/or heating power by a resonant tank (30), in particular a resonant circuit, which resonant tank (30) is in particular connected to a first node (21),
driving a switching element (35), in particular a single switching element, which is connected to the resonant tank (30), in particular via the first node (21), with a switching signal for oscillating the resonant tank (30),
-measuring a first electrical parameter of the oscillating circuit (2), in particular the first node (21), by a measuring unit (40)
Node voltage (V) CE ) And (b)
-estimating, by an estimation unit (45), a second electrical parameter, in particular electrical power, of the oscillating circuit (2) based on the first electrical parameter.
14. Method for operating an oscillating unit (2) according to claim 13, further comprising, in particular by the estimating unit (45):
-deriving the first electrical parameter based on the sampled first electrical parameter by a deriving unit (47) to obtain a derivative, in particular by applying a numerical differentiation to the sampled first electrical parameter, and/or
-multiplying the sampled first electrical parameter with a derivative of the first electrical parameter and in particular a constant factor by a multiplication unit (46) to obtain a multiplication result, and/or
-averaging the multiplication result by an averaging device (48) over a predetermined time, in particular during the off-time of the switching device (35), to obtain an average value, and/or
-multiplying the first and third electrical parameters to obtain a total electrical power, and/or
-calculating a weighted difference between the total electrical power and the second electrical parameter, and/or
Obtaining the second electrical parameter from a look-up table based on the first electrical parameter,
-wherein, in particular, the constant factor is the capacitance (C) of the capacitive resonator element (31), and/or
Wherein in particular the second electrical parameter is the multiplication result or the average value, and/or
-wherein in particular the second electrical parameter is an indicator of the electrical power of the oscillating circuit and/or of the electrical power of the oscillating circuit.
15. Method for operating an oscillating unit (2) according to claim 13 or 14, further comprising:
controlling the resonant tank (30) by a control unit (50) by determining a switching parameter of the switching signal, in particular based on the second electrical parameter and/or the requested power, such that the power of the inductive resonant element and/or the resonant tank is controlled in a control loop and/or in a closed loop,
wherein, in particular, the control by the control unit (50) comprises:
-determining, by the power determining unit (51), the requested power based on the requested power level, and/or
-controlling the power of the resonant tank (30) by a power control unit (52) based on the requested power/the requested power and the second electrical parameter, and/or
In particular, wherein the requested power is the nominal value or set point, and/or wherein the second electrical parameter is the actual value of the control loop, and/or
In particular, wherein the resonant tank, more particularly the actual power thereof, is controlled by adjusting at least one switching parameter, more particularly an on-time and/or an off-time, wherein in particular the on-time defines how long the switching element is in the closed state, preferably during a switching cycle, and/or the off-time defines how long the switching element is in the open state, particularly during the same switching cycle, and/or
-in particular, wherein the on-time is adjusted for controlling the resonance tank (30), and/or wherein the resonance frequency and the corresponding period of the resonance tank (30) are determined for controlling a subsequent off-time, which is preferably determined based on the voltage at the switching element, and/or wherein more particularly the off-time is based on detecting a zero crossing of the voltage at the switching element.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP202012092 | 2020-10-12 | ||
| EP20012092 | 2020-10-12 | ||
| PCT/EP2021/076783 WO2022078757A1 (en) | 2020-10-12 | 2021-09-29 | Oscillation unit, induction cooking appliance and method for operating an oscillation unit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116326205A true CN116326205A (en) | 2023-06-23 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202180069241.XA Pending CN116326205A (en) | 2020-10-12 | 2021-09-29 | Oscillating unit, induction cooking appliance and method for operating an oscillating unit |
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| Country | Link |
|---|---|
| CN (1) | CN116326205A (en) |
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2021
- 2021-09-29 CN CN202180069241.XA patent/CN116326205A/en active Pending
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