Control method for heating device and heating device

Abstract

The present invention provides a control method and a heating device for a heating device. The heating device includes an electromagnetic wave generating module for generating an electromagnetic wave signal for heating an object to be processed, and a matching module for reducing the return loss of the electromagnetic wave generating module. The control method includes: a heating start step: controlling the electromagnetic wave generating module to generate an electromagnetic wave signal; a configuration confirmation step: adjusting the configuration of the matching module and the frequency of the electromagnetic wave signal, and determining the optimal configuration of the matching module and the optimal frequency of the electromagnetic wave signal to achieve the minimum return loss of the electromagnetic wave generating module; an impedance matching step: adjusting the matching module to the optimal configuration, and controlling the electromagnetic wave generating module to generate an electromagnetic wave signal at the optimal frequency. The present invention uses a matching module that only includes a few electrical components to adjust the impedance changes caused by food materials in a large weight range, and realizes fine impedance adjustment. The control logic is simple, which reduces the production cost and maintenance cost of the heating device.

Description

Technical Field

[0001] The present invention relates to the field of food processing, and in particular to a control method for an electromagnetic wave heating device and a heating device. Background Art

[0002] During the freezing process of food, the quality of the food is maintained, but the frozen food needs to be thawed before processing or eating. In order to facilitate users to thaw the food, an electromagnetic wave heating device is usually used to thaw the food.

[0003] Thawing food by electromagnetic wave heating device is not only fast and efficient, but also has low loss of nutritional components in food. It is necessary to ensure the heating efficiency of electromagnetic wave on food by ensuring the impedance matching of electromagnetic wave generating module. However, the prior art generally only achieves impedance matching of electromagnetic wave generating module by adjusting the impedance of impedance matching module itself. If the matching module is to be able to adjust the impedance change caused by food with a larger weight range, the circuit of the matching module needs to include more electrical components. Correspondingly, the connection structure and control logic of the circuit are also more complicated, which increases the production cost and maintenance cost of the heating device.

[0004] Taking all factors into consideration, it is necessary to provide a control method and a heating device for an electromagnetic wave heating device which have a simple structure, simple control logic and can adjust impedance over a large range. Summary of the invention

[0005] An object of the first aspect of the present invention is to overcome at least one technical defect in the prior art and to provide a control method for an electromagnetic wave heating device.

[0006] A further object of the first aspect of the present invention is to simplify the structure of the matching module and simplify the control logic.

[0007] Another further object of the first aspect of the present invention is to improve the accuracy of determining whether heating is completed.

[0008] An object of the second aspect of the present invention is to provide an electromagnetic wave heating device.

[0009] According to a first aspect of the present invention, a control method for a heating device is provided, wherein the heating device comprises an electromagnetic wave generating module for generating an electromagnetic wave signal for heating an object to be processed, and a matching module for reducing the return loss of the electromagnetic wave generating module, wherein the control method comprises:

[0010] Heating start step: controlling the electromagnetic wave generating module to generate an electromagnetic wave signal;

[0011] Configuration confirmation step: adjusting the configuration of the matching module and the frequency of the electromagnetic wave signal, and determining the optimal configuration of the matching module and the optimal frequency of the electromagnetic wave signal for achieving the minimum return loss of the electromagnetic wave generating module;

[0012] Impedance matching step: adjusting the matching module to the optimal configuration, and controlling the electromagnetic wave generating module to generate an electromagnetic wave signal according to the optimal frequency.

[0013] Optionally, the control method further includes:

[0014] Parameter determination step: determining a termination parameter threshold for completing heating according to the optimal configuration;

[0015] Heating termination step: when the corresponding parameter reaches the termination parameter threshold, the electromagnetic wave generating module is controlled to stop generating the electromagnetic wave signal.

[0016] Optionally, the termination parameter is the total heating time, the S11 change rate, the forward power change rate, or the reverse power change rate.

[0017] Optionally, the configuration confirmation step includes:

[0018] The matching module is sequentially adjusted to a preset first configuration and a second configuration, and the frequency of the electromagnetic wave signal is adjusted within a preset first frequency interval and a preset second frequency interval, respectively, and the frequency values ​​corresponding to the first configuration and the second configuration for achieving minimum return loss and the return parameters reflecting the return loss are determined and recorded;

[0019] comparing echo parameters corresponding to the first configuration and the second configuration;

[0020] If the return loss reflected by the return parameter corresponding to the first configuration is greater than that of the second configuration, determining the optimal configuration from the second configuration and other configurations having the same impedance value change trend as the second configuration relative to the first configuration;

[0021] If the return loss reflected by the return parameter corresponding to the first configuration is smaller than that of the second configuration, the optimal configuration is determined among the first configuration and other configurations having an opposite impedance value change trend to that of the second configuration relative to the first configuration.

[0022] Optionally, the second frequency interval is divided by the frequency value corresponding to the first configuration, within the first frequency interval, according to a change trend of the second configuration opposite to that of the first configuration.

[0023] Optionally, after the impedance matching step, the control method further includes:

[0024] Echo inspection step: obtaining an echo parameter reflecting echo loss, wherein the echo parameter is an S11 coefficient;

[0025] Matching correction step: when the echo parameter is greater than a preset upper threshold, readjusting the configuration of the matching module and the frequency of the electromagnetic wave signal.

[0026] Optionally, in the matching correction step, based on the current configuration of the matching module, the frequency value of the minimum echo parameter is determined within a frequency range less than the previous frequency; if the minimum echo parameter is less than or equal to the upper limit threshold, the electromagnetic wave generating module is controlled to generate an electromagnetic wave signal according to the frequency value of the minimum echo parameter; if the minimum echo parameter is greater than the upper limit threshold, the configuration of the matching module is adjusted to a corresponding impedance value greater than the current configuration and closest to the current configuration, and based on the configuration, a new minimum frequency value of the echo parameter is determined within a frequency range less than the previous minimum frequency value of the echo parameter, until the new minimum echo parameter is less than or equal to the upper limit threshold.

[0027] Optionally, the control method further includes:

[0028] Parameter determination step: determining a termination parameter threshold for completing heating according to the optimal configuration;

[0029] Heating termination step: when the corresponding parameter reaches the termination parameter threshold, the electromagnetic wave generating module is controlled to stop generating the electromagnetic wave signal; wherein

[0030] The termination parameter is the S11 change rate, the forward power change rate, or the reverse power change rate; and

[0031] When the corresponding parameter reaches the termination parameter threshold and the echo parameter is greater than the upper limit threshold, the matching correction step is performed.

[0032] Optionally, if the optimal frequency is less than a preset frequency threshold, the electromagnetic wave generating module is controlled to stop generating the electromagnetic wave signal.

[0033] According to a second aspect of the present invention, there is provided a heating device, characterized in that it comprises:

[0034] Cavity capacitor, used to place the object to be processed;

[0035] An electromagnetic wave generating module, configured to generate an electromagnetic wave signal for heating the object to be processed in the cavity capacitor;

[0036] a matching module, connected in series between the electromagnetic wave generating module and the cavity capacitor, and comprising a plurality of matching branches connected in parallel, for reducing the return loss of the electromagnetic wave generating module; and

[0037] A controller configured to execute any of the control methods described above; wherein

[0038] The electromagnetic wave generating module is provided with a voltage-controlled oscillator for adjusting the frequency of the electromagnetic wave signal.

[0039] The present invention reduces the return loss of the electromagnetic wave generating module by adjusting the configuration of the matching module and the frequency of the electromagnetic wave signal at the same time. The impedance change caused by food in a larger weight range can be adjusted by using a matching module including only a few electrical components, and fine impedance adjustment can be achieved. The control logic is simple, and the production cost and maintenance cost of the heating device are reduced.

[0040] Furthermore, the present invention can greatly shorten the time consumed for impedance matching by confirming or correcting the optimal configuration and optimal frequency through a special matching module configuration and the adjustment logic of the electromagnetic wave signal frequency, thereby shortening the total time to complete heating, reducing energy consumption, and reducing the impact of electromagnetic waves on food during the impedance matching stage, thereby ensuring the quality of the heated food and improving the user experience.

[0041] Furthermore, the present invention determines the termination parameter threshold for completing heating through the optimal configuration of the matching module determined by the initial matching, which not only improves the user's operating convenience and saves costs, but also unexpectedly reduces or even eliminates the influence of the object-receiving dish to be processed, reduces the error of the termination parameter threshold, and can obtain the termination parameter threshold that allows the object to be processed to end in the state expected by the user without manual input by the user and without adding additional measuring devices.

[0042] Based on the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings, those skilled in the art will become more aware of the above and other objects, advantages and features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

[0044] Figure 1 is a schematic structural diagram of an electromagnetic wave heating device according to an embodiment of the present invention;

[0045] Figure 2 yes Figure 1 A schematic structural diagram of the controller;

[0046] Figure 3 yes Figure 1 A schematic circuit diagram of the matching module;

[0047] Figure 4is a schematic flow chart of a control method for a heating device according to an embodiment of the present invention;

[0048] Figure 5 is a schematic detailed flow chart of a control method for a heating device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0049] Figure 1 is a schematic structural diagram of an electromagnetic wave heating device 100 according to an embodiment of the present invention. Figure 1 The heating device 100 may include a cavity capacitor 110 , an electromagnetic wave generating module 120 , a matching module 130 and a controller 140 .

[0050] Specifically, the cavity capacitor 110 may include a cavity for placing the object to be processed 150 and a radiation plate disposed in the cavity. In some embodiments, a receiving plate may also be disposed in the cavity to form a capacitor with the radiation plate. In other embodiments, the cavity may be made of metal to form a capacitor with the receiving plate and the radiation plate.

[0051] The electromagnetic wave generating module 120 may be configured to generate an electromagnetic wave signal and be electrically connected to the radiation plate of the cavity capacitor 110 to generate electromagnetic waves in the cavity capacitor 110 , thereby heating the object to be processed 150 in the cavity capacitor 110 .

[0052] In some embodiments, the electromagnetic wave generating module 120 may include a voltage controlled oscillator 121 and a power amplifier to adjust the frequency and power of the electromagnetic wave generating signal.

[0053] The matching module 130 can be connected in series between the electromagnetic wave generating module 120 and the cavity capacitor 110 or in parallel at both ends of the cavity capacitor 110, and is configured to adjust the load impedance of the electromagnetic wave generating module 120 by adjusting its own impedance to reduce the return loss of the electromagnetic wave generating module 120, achieve load matching, and improve heating efficiency.

[0054] Figure 2 yes Figure 1 140 is a schematic structural diagram of the controller 140. Figure 2 The controller 140 may include a processing unit 141 and a storage unit 142. The storage unit 142 stores a computer program 143, and the computer program 143 is used to implement the control method of the embodiment of the present invention when executed by the processing unit 141.

[0055] In particular, the processing unit 141 can be configured to control the electromagnetic wave generating module 120 to generate an electromagnetic wave signal, adjust the configuration of the matching module 130 and the frequency of the electromagnetic wave signal, and determine the optimal configuration of the matching module 130 and the optimal frequency of the electromagnetic wave signal that achieve the minimum return loss of the electromagnetic wave generating module 120, and then adjust the matching module 130 to the optimal configuration and control the electromagnetic wave generating module 120 to generate an electromagnetic wave signal at the optimal frequency.

[0056] In the process of confirming the optimal configuration and the optimal frequency, the electromagnetic wave generating module 120 may generate an electromagnetic wave signal of a preset initial power; after adjusting the matching module 130 to the optimal configuration and the electromagnetic wave signal to the optimal frequency, the electromagnetic wave generating module 120 may generate an electromagnetic wave signal of a preset heating power, and formally start heating the object to be processed 150. The preset initial power may be less than the preset heating power to reduce the influence of the electromagnetic wave on the object to be processed 150 during impedance matching.

[0057] The heating device 100 of the present invention reduces the return loss of the electromagnetic wave generating module 120 by simultaneously adjusting the configuration of the matching module 130 and the frequency of the electromagnetic wave signal. The matching module 130 including only a few electrical components can adjust the impedance changes caused by food in a larger weight range and achieve fine impedance adjustment. The control logic is simple, which reduces the production cost and maintenance cost of the heating device 100.

[0058] In some embodiments, the processing unit 141 may be further configured to control the electromagnetic wave generating module 120 to stop generating electromagnetic wave signals when the optimal frequency is less than a preset frequency threshold, so as to avoid wasting energy due to the poor absorption capacity of the object 150 to be processed for electromagnetic waves.

[0059] In some embodiments, the processing unit 141 can be further configured to determine a termination parameter threshold for completing heating based on the determined optimal configuration of the matching module 130, and when the corresponding parameter reaches the termination parameter threshold, control the electromagnetic wave generating module 120 to stop generating electromagnetic wave signals, thereby ending the heating of the object to be processed 150, so as to improve the user's operating convenience, save costs, and reduce errors, so that the object to be processed 150 ends in the state expected by the user.

[0060] The termination parameter may be the total heating time, the S11 change rate, the change rate of the forward power, or the change rate of the reverse power.

[0061] For example, the termination parameter is the total heating time, and the current heating time is greater than or equal to the total heating time, which means that the corresponding parameter has reached the termination parameter threshold; the termination parameter is the S11 change rate, or the forward power change rate, and the current S11 change rate is less than or equal to the preset S11 change rate threshold, or the current forward power change rate is less than or equal to the preset forward change rate threshold, which means that the corresponding parameter has reached the termination parameter threshold; the termination parameter is the reverse power change rate, and the current reverse power change rate is greater than or equal to the preset reverse change rate threshold, which means that the corresponding parameter has reached the termination parameter threshold.

[0062] The heating device 100 may also include a forward coupler and / or a reverse coupler connected in series between the matching module 130 and the electromagnetic wave generating module 120, which is used to monitor the forward power signal output by the electromagnetic wave generating module 120 and / or the reverse power signal returned to the electromagnetic wave generating module 120 in real time, and then calculate the S11 coefficient, the S11 change rate, the forward power change rate, or the reverse power change threshold.

[0063] Figure 3 yes Figure 1 Schematic circuit diagram of the matching module 130 (in the figure, "IN" represents the end connected to the electromagnetic wave generating module 120; "OUT" represents the end connected to the cavity capacitor 110). Figure 3 The matching module 130 can be connected in series between the electromagnetic wave generating module 120 and the cavity capacitor 110, and includes a plurality of matching branches connected in parallel.

[0064] In the illustrated embodiment, the plurality of matching branches include capacitors C1, C2, ..., C n and C n+1 , where capacitors C1, C2, ..., C n The switches K1, K2, ..., K n Independent control. Capacitors C1, C2, ..., C n The capacitance values ​​may be unequal to increase the adjustment range of the matching module 130 .

[0065] In some exemplary embodiments, the multiple matching branches include a total of 3 matching branches independently controlled by switches (i.e., n=3), and the capacitance value of the capacitor of each matching branch is not equal, so the matching module 130 can form 8 configurations according to the different opening and closing states of the 3 switches, and the 8 configurations are numbered P0 to P7 in sequence from large to small according to the impedance value.

[0066] Tables 1 and 2 show the frequency value and S11 coefficient with the minimum return loss for each configuration under the same test conditions, which were tested at 39.7MHz to 42.2MHz with a step of 20kHz. The weights in the tables are only the weights of beef; the mark "remove the container" means that the cavity capacitor 110 does not contain a container (such as a tray or drawer) during the test; the mark "remove the container" does not mean that a container is provided in the cavity capacitor 110 to carry the beef to be tested during the test. Among them, the weight and material of the containers used in the test are the same; the beef used in the test is all lean meat from the same part, but due to slight differences in parameters such as fat content of different beef, the test results of the same weight of beef tested in the same way will be slightly different.

[0067] Table 1

[0068]

[0069]

[0070] Table 2

[0071]

[0072] It can be seen from the test results in Table 1 that the configurations of the matching module 130 with the smallest return loss are all different for beef of different weights. That is, in combination with the determination of the optimal frequency, the weight of the object to be processed 150 can be accurately determined according to the optimal configuration, and then the termination parameter threshold for completing heating can be accurately determined, so that the object to be processed 150 ends in the state expected by the user.

[0073] It can be seen from the test results in Table 2 that the optimal configuration determined for the same weight of beef is the same when the container is removed from the cavity capacitor 110 and when the container is set in the cavity capacitor 110. That is, in combination with the determination of the optimal frequency, the weight of the object to be processed 150 or the termination parameter threshold for completing heating can be determined according to the optimal configuration, and the error caused by the container set in the cavity capacitor 110 can be completely ignored, so that the user can flexibly use different containers to carry the object to be processed 150 during use.

[0074] However, if the impedance matching of the electromagnetic wave generating module 120 is achieved only by adjusting the impedance of the matching module 130 itself, and the weight of the beef is determined by the optimal configuration of the matching module 130, even if a set of independently controllable grounding capacitors in parallel is added on the basis of the existing circuit, and a holding dish is provided in the cavity capacitor 110, about 150 grams (g) of beef will be determined as about 300 g of beef, and about 300 g of beef will be determined as about 500 g of beef, which has a large error.

[0075] In some embodiments, in the process of confirming the optimal configuration and the optimal frequency, the processing unit 141 can be further configured to narrow the screening interval of the optimal configuration and the optimal frequency once or multiple times, and then determine the optimal configuration and the optimal frequency within the narrowed screening interval to improve matching efficiency.

[0076] Specifically, the processing unit 141 can adjust the matching module 130 to the preset first configuration and the second configuration in sequence, and adjust the frequency of the electromagnetic wave signal in the preset first frequency range and the second frequency range respectively, determine and record the frequency values ​​corresponding to the first configuration and the second configuration that achieve the minimum return loss, and the echo parameters reflecting the return loss, compare the echo parameters corresponding to the first configuration and the second configuration, and achieve a reduction in the screening interval for the optimal configuration and the optimal frequency.

[0077] If the return loss reflected by the echo parameters corresponding to the first configuration is greater than that of the second configuration, the optimal configuration is subsequently determined among the second configuration and other configurations with the same impedance value change trend as that of the second configuration relative to the first configuration; if the return loss reflected by the echo parameters corresponding to the first configuration is less than that of the second configuration, the optimal configuration is subsequently determined among the first configuration and other configurations with the opposite impedance value change trend as that of the second configuration relative to the first configuration.

[0078] The second frequency interval can be divided by the frequency value corresponding to the first configuration, within the first frequency interval, according to the change trend of the second configuration opposite to the first configuration, so as to further improve the matching efficiency. The bandwidth of the first frequency interval can be 2MHz to 3MHz, for example, 39.7MHz to 42.2MHz. The processing unit 141 can adjust the frequency of the electromagnetic wave signal in steps of 15kHz to 30kHz, for example, 20kHz.

[0079] Similarly, the processing unit 141 may determine the optimal configuration and the optimal frequency in other configurations and the newly divided frequency intervals according to a similar screening range narrowing logic.

[0080] The echo parameter may be an S11 coefficient, a forward power value, or a reverse power value of the line between the matching module 130 and the electromagnetic wave generating module 120 .

[0081] For example, when the echo parameter is the S11 coefficient, the S11 coefficient corresponding to the first configuration is greater than the S11 coefficient corresponding to the second configuration, which means that the echo loss of the first configuration is greater than that of the second configuration; when the echo parameter is the reverse power value, the reverse power value corresponding to the first configuration is less than the reverse power value corresponding to the second configuration, which means that the echo loss of the first configuration is greater than that of the second configuration.

[0082] Taking 450g of beef in Table 1 as an example, the process of confirming the optimal configuration and optimal frequency may include: adjusting the configuration of the matching module 130 to P3, performing S11 coefficient tests on all frequency values ​​within 39.7MHz to 42.2MHz with a step of 20kHz, and determining that the minimum S11 coefficient is -14.5 and the corresponding frequency is 40.864MHz. Adjusting the configuration of the matching module 130 to P2, performing S11 coefficient tests on all frequency values ​​within 40.864MHz to 42.2MHz with a step of 20kHz, and determining that the minimum S11 coefficient is -9.5 and the corresponding frequency is 40.9315MHz. It is determined that the minimum S11 coefficient corresponding to configuration P2 is greater than the minimum S11 coefficient corresponding to configuration P3, so the optimal configuration is determined in configurations P3 to P7.

[0083] The configuration of the matching module 130 is adjusted to P4, and the S11 coefficient is tested for all frequency values ​​within 39.7MHz to 40.864MHz with a step of 20kHz, and it is determined that the minimum S11 coefficient is -32 and the corresponding frequency is 40.7605MHz. It is determined that the minimum S11 coefficient corresponding to configuration P4 is less than the minimum S11 coefficient corresponding to configuration P3, so the optimal configuration is determined in configurations P4 to P7.

[0084] The configuration of the matching module 130 is adjusted to P5, and the S11 coefficient is tested for all frequency values ​​within 39.7MHz to 40.7605MHz with a step of 20kHz, and it is determined that the minimum S11 coefficient is -22 and the corresponding frequency is 40.702MHz. It is determined that the minimum S11 coefficient corresponding to the configuration P5 is greater than the minimum S11 coefficient corresponding to the configuration P4, so the optimal configuration is determined to be P4.

[0085] In some embodiments, after the impedance matching is completed for the first time (i.e., after the optimal configuration and the optimal frequency are determined for the first time), the processing unit 141 can be further configured to obtain the S11 coefficient reflecting the return loss. When the S11 coefficient is greater than a preset upper limit threshold, the configuration of the matching module 130 and the frequency of the electromagnetic wave signal are readjusted (i.e., the optimal configuration and the optimal frequency are corrected) so that the S11 coefficient is less than or equal to the preset upper limit threshold, thereby ensuring the absorption rate of the electromagnetic wave by the object 150 to be processed.

[0086] In some further embodiments, in the process of re-adjusting the configuration of the matching module 130 and the frequency of the electromagnetic wave signal, the processing unit 141 may be configured to determine the minimum frequency value of the echo parameter within a frequency range less than the previous frequency based on the current configuration of the matching module 130; if the minimum echo parameter is less than or equal to a preset upper limit threshold, the electromagnetic wave generating module 120 is controlled to generate an electromagnetic wave signal according to the minimum frequency value of the echo parameter; if the minimum echo parameter is still greater than the preset upper limit threshold, the configuration of the matching module 130 is adjusted to a corresponding impedance value greater than the current configuration and closest to the current configuration, and based on the configuration, a new minimum frequency value of the echo parameter is determined within a frequency range less than the previous minimum frequency value of the echo parameter, until the new minimum echo parameter is less than or equal to the preset upper limit threshold, so as to shorten the time for re-matching.

[0087] In the process of re-adjusting the configuration of the matching module 130 and the frequency of the electromagnetic wave signal, the electromagnetic wave generating module 120 may generate an electromagnetic wave signal with a preset initial power to reduce the influence of the electromagnetic wave on the object to be processed 150 during the re-adjustment.

[0088] Table 3 shows the configuration of the matching module 130, the frequency of the electromagnetic wave signal and the corresponding S11 coefficient at different times during the process of re-adjusting the configuration of the matching module 130 and the frequency of the electromagnetic wave signal in a test on 500g of beef. Wherein "'" means "minutes"; """ means "seconds".

[0089] Table 3

[0090]

[0091]

[0092] In the embodiment of Table 3, the upper limit threshold of the S11 coefficient may be -13, and the S11 coefficient is re-acquired every 30″. The table only records the S11 coefficient and the corresponding time obtained for the first time and the last time after each readjustment, and the S11 coefficients obtained at other times not shown are all less than or equal to the preset upper limit threshold.

[0093] The process of re-adjusting the configuration of the matching module 130 and the frequency of the electromagnetic wave signal may include: the initial optimal configuration is P4, the optimal frequency is 40.86 MHz, and the corresponding S11 coefficient is -35.

[0094] When the S11 coefficient is -10.4 and greater than the preset upper threshold, the configuration of the matching module 130 is kept unchanged, the frequency of the electromagnetic wave signal is adjusted, and the frequency value with the minimum return loss is re-determined to be 40.765MHz within 39.7MHz to 40.86MHz, and the corresponding S11 coefficient is -18.6 and less than or equal to the preset upper threshold, and heating is continued at this frequency value. And so on.

[0095] At 3', the obtained S11 coefficient is -11.6 and is greater than the preset upper threshold. The configuration of the matching module 130 remains unchanged, the frequency of the electromagnetic wave signal is adjusted, and the frequency value with the minimum return loss is re-determined to be 40.57MHz within 39.7MHz to 40.615MHz. The corresponding S11 coefficient is -12.9 but greater than the preset upper threshold. The configuration of the matching module 130 is adjusted to P5 and P6 in turn, and the frequency value with the minimum return loss is re-determined. The corresponding S11 coefficient is still greater than the preset upper threshold.

[0096] The configuration of the adjustment matching module 130 is P7, the frequency of the electromagnetic wave signal is adjusted and the frequency value with the minimum return loss is re-determined to be 40.395 MHz between 39.7 MHz and the frequency value with the minimum return loss corresponding to P6, and the corresponding S11 coefficient is -30 and is less than or equal to the preset upper limit threshold, and heating continues at this frequency value.

[0097] If the S11 coefficient is greater than the preset upper threshold, the configuration of the matching module 130 is kept unchanged at P7, and the frequency of the electromagnetic wave signal is adjusted until the S11 change rate is less than or equal to the preset S11 change rate threshold.

[0098] When the termination parameter is the S11 change rate, the forward power change rate, or the reverse power change rate, when the corresponding parameter reaches the termination parameter threshold and the echo parameter is greater than the upper threshold (i.e., the heating termination condition and the re-impedance matching condition are met at the same time), the configuration of the matching module 130 and the frequency of the electromagnetic wave signal are corrected first to prevent misjudgment. After the correction is completed, the processing unit 141 can re-acquire the S11 coefficient, and if the corresponding parameter still reaches the termination parameter threshold, the electromagnetic wave generating module 120 is controlled to stop generating the electromagnetic wave signal.

[0099] Figure 4 is a schematic flow chart of a control method for a heating device 100 according to an embodiment of the present invention. Figure 4 The control method for the heating device 100 executed by the controller 140 of any of the above embodiments of the present invention may include the following steps:

[0100] Step S402 (heating start step): controlling the electromagnetic wave generating module 120 to generate an electromagnetic wave signal.

[0101] Step S404 (configuration confirmation step): adjust the configuration of the matching module 130 and the frequency of the electromagnetic wave signal, and determine the optimal configuration of the matching module 130 and the optimal frequency of the electromagnetic wave signal to achieve the minimum return loss of the electromagnetic wave generating module 120. In this step, the power of the electromagnetic wave signal can be a preset initial power.

[0102] Step S406 (impedance matching step): adjust the matching module 130 to the optimal configuration, and control the electromagnetic wave generating module 120 to generate an electromagnetic wave signal at the optimal frequency. In this step, the power of the electromagnetic wave signal may be a preset heating power. The preset initial power may be less than the preset heating power to reduce the influence of the electromagnetic wave on the object to be processed 150 during impedance matching.

[0103] The control method of the present invention reduces the return loss of the electromagnetic wave generating module 120 by adjusting the configuration of the matching module 130 and the frequency of the electromagnetic wave signal at the same time. The matching module 130 including only a few electrical components can adjust the impedance changes caused by food in a larger weight range and achieve fine impedance adjustment. The control logic is simple, which reduces the production cost and maintenance cost of the heating device 100.

[0104] In some embodiments, before step S406, the control method of the present invention may further include the following steps:

[0105] If the optimal frequency is less than the preset frequency threshold, the electromagnetic wave generating module 120 is controlled to stop generating electromagnetic wave signals to avoid wasting energy due to the poor absorption capacity of the object 150 to be processed to electromagnetic waves.

[0106] In some embodiments, after step S404, the control method of the present invention may further include the following steps:

[0107] Parameter determination step: Determine the termination parameter threshold for completing heating according to the optimal configuration, wherein the termination parameter may be the total heating time, the S11 change rate, the change rate of the forward power, or the change rate of the reverse power.

[0108] Heating termination step: When the corresponding parameter reaches the termination parameter threshold, the electromagnetic wave generating module 120 is controlled to stop generating the electromagnetic wave signal, and the heating of the object to be processed 150 is terminated to improve the user's operating convenience, save costs, and reduce errors, so that the object to be processed 150 ends in the state expected by the user.

[0109] In some embodiments, step S404 (configuration confirmation step) may further include the following steps:

[0110] The matching module 130 is sequentially adjusted to a preset first configuration and a second configuration, and the frequency of the electromagnetic wave signal is adjusted within a preset first frequency interval and a preset second frequency interval, respectively, and the frequency values ​​for achieving the minimum return loss corresponding to the first configuration and the second configuration, and the return parameters reflecting the return loss are determined and recorded;

[0111] comparing echo parameters corresponding to the first configuration and the second configuration;

[0112] If the return loss reflected by the return parameter corresponding to the first configuration is greater than that of the second configuration, determining the optimal configuration among the second configuration and other configurations having the same impedance value change trend as the second configuration relative to the first configuration;

[0113] If the return loss reflected by the return parameter corresponding to the first configuration is smaller than that of the second configuration, the optimal configuration is determined among the first configuration and other configurations having an opposite impedance value change trend to that of the second configuration relative to the first configuration.

[0114] The present invention improves matching efficiency by narrowing the screening range of optimal configuration and optimal frequency once or multiple times, and then determining the optimal configuration and optimal frequency within the narrowed screening range, thereby shortening the total time to complete heating, reducing energy consumption, and reducing the impact of electromagnetic waves on food in the impedance matching stage, thereby ensuring the quality of the heated food and improving user experience.

[0115] The second frequency interval may be divided by the frequency value corresponding to the first configuration within the first frequency interval according to a change trend of the second configuration opposite to the first configuration, so as to further improve the matching efficiency.

[0116] The echo parameter may be an S11 coefficient, a forward power value, or a reverse power value of the line between the matching module 130 and the electromagnetic wave generating module 120 .

[0117] In some embodiments, after step S406 (impedance matching step), the control method of the present invention may further include the following steps:

[0118] Echo inspection steps: obtaining an echo parameter reflecting the echo loss, the echo parameter being the S11 coefficient;

[0119] Matching correction step: when the echo parameter is greater than the preset upper threshold, readjust the configuration of the matching module 130 and the frequency of the electromagnetic wave signal to make the S11 coefficient less than or equal to the preset upper threshold, thereby ensuring the absorption rate of the object 150 to the electromagnetic wave.

[0120] In some further embodiments, in the matching correction step, the minimum frequency value of the echo parameter can be determined within a frequency range less than the previous frequency based on the current configuration of the matching module 130; if the minimum echo parameter is less than or equal to an upper threshold value, the electromagnetic wave generating module 120 is controlled to generate an electromagnetic wave signal according to the minimum frequency value of the echo parameter; if the minimum echo parameter is greater than the upper threshold value, the configuration of the matching module 130 is adjusted to a corresponding impedance value greater than the current configuration and closest to the current configuration, and based on the configuration, a new minimum frequency value of the echo parameter is determined within a frequency range less than the previous minimum frequency value of the echo parameter, until the new minimum echo parameter is less than or equal to the upper threshold value, so as to shorten the time for re-matching.

[0121] In some embodiments where the termination parameter is the S11 change rate, the forward power change rate, or the reverse power change threshold, when the corresponding parameter reaches the termination parameter threshold and the echo parameter is greater than the upper threshold (i.e., the heating termination condition and the re-impedance matching condition are met at the same time), the matching correction step is performed first to prevent misjudgment. After the correction is completed, the S11 coefficient is re-obtained to determine whether the heating termination condition is met.

[0122] The control method of the present invention is described in detail below by taking the case where the impedance value of the preset first configuration is greater than the impedance value of the second configuration as an example.

[0123] Figure 5 is a schematic detailed flow chart of a control method for a heating device 100 according to an embodiment of the present invention (in the figure, "Y" means "yes"; "N" means "no"). Figure 5 The control method for the heating device 100 of the present invention may include the following detailed steps:

[0124] Step S502: Obtain heating instructions.

[0125] Step S504: controlling the electromagnetic wave generating module 120 to generate an electromagnetic wave signal with a preset initial power.

[0126] Step S506: sequentially adjust the matching module 130 to the preset first configuration and the second configuration, and adjust the frequency of the electromagnetic wave signal in the first frequency interval and the second frequency interval respectively, determine and record the frequency value of the electromagnetic wave signal that achieves the minimum return loss of the electromagnetic wave generating module 120 based on the first configuration and the second configuration (respectively recorded as the first frequency value and the second frequency value), and the corresponding S11 coefficient (respectively recorded as the first S11 coefficient and the second S11 coefficient). In this step, the second frequency interval can be the part of the first frequency interval that is greater than the first frequency value.

[0127] Step S508: Determine whether the first S11 coefficient is greater than the second S11 coefficient. If so, execute step S510; if not, execute step S512.

[0128] Step S510: determining the optimal configuration of the matching module 130 in other configurations whose impedance values ​​are smaller than the second configuration, and determining the optimal frequency in the portion of the first frequency interval that is greater than the second frequency value.

[0129] Step S512: determining the optimal configuration of the matching module 130 in other configurations having impedance values ​​greater than the first configuration, and determining the optimal frequency in a portion of the first frequency interval less than the first frequency value.

[0130] Step S514: Determine whether the optimal frequency is less than a preset frequency threshold. If so, execute step S528; if not, execute step S516.

[0131] Step S516: Adjust the configuration of the matching module 130 to the determined optimal configuration, and control the electromagnetic wave generating module 120 to generate an electromagnetic wave signal with a preset heating power according to the determined optimal frequency, so as to start formally heating the object to be processed 150. And determine the total heating time required to heat the object to be processed 150 according to the optimal configuration.

[0132] Step S518: Determine whether the current heating time is greater than or equal to the determined total heating time. If so, execute step S528; if not, execute step S520.

[0133] Step S520: Obtain the S11 coefficient that currently reflects the return loss of the electromagnetic wave generating module 120. Execute steps S518 and S522.

[0134] Step S522: Determine whether the current S11 coefficient is less than a preset lower threshold value. If yes, return to step S520; if no, execute step S524.

[0135] Step S524: Based on the current configuration of the matching module 130, determine the minimum frequency value of the echo parameter within a frequency range less than the previous frequency; if the minimum echo parameter is less than or equal to a preset upper limit threshold, control the electromagnetic wave generating module 120 to generate an electromagnetic wave signal according to the minimum frequency value of the echo parameter; if the minimum echo parameter is still greater than the preset upper limit threshold, adjust the configuration of the matching module 130 so that the corresponding impedance value is greater than the current configuration and closest to the current configuration, and determine a new minimum frequency value of the echo parameter based on the configuration within a frequency range less than the minimum frequency value of the previous echo parameter.

[0136] Step S526: Control the electromagnetic wave generating module 120 to stop working, that is, stop generating electromagnetic wave signals, and end the heating of the object to be processed 150.

[0137] At this point, those skilled in the art should recognize that, although multiple exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived based on the content disclosed in the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all these other variations or modifications.

Claims

1. A control method for a heating device, the heating device comprising an electromagnetic wave generating module for generating an electromagnetic wave signal for heating an object to be processed, and a matching module for reducing the return loss of the electromagnetic wave generating module, It is characterized in that The control method comprises: Heating start step: controlling the electromagnetic wave generating module to generate an electromagnetic wave signal; Configuration confirmation step: adjusting the configuration of the matching module and the frequency of the electromagnetic wave signal, and determining the optimal configuration of the matching module and the optimal frequency of the electromagnetic wave signal for achieving the minimum return loss of the electromagnetic wave generating module; Impedance matching step: adjusting the matching module to the optimal configuration, and controlling the electromagnetic wave generating module to generate an electromagnetic wave signal according to the optimal frequency; wherein the configuration confirmation step includes: The matching module is sequentially adjusted to a preset first configuration and a second configuration, and the frequency of the electromagnetic wave signal is adjusted within a preset first frequency interval and a preset second frequency interval, respectively, and the frequency values ​​corresponding to the first configuration and the second configuration for achieving minimum return loss and the return parameters reflecting the return loss are determined and recorded; comparing echo parameters corresponding to the first configuration and the second configuration; If the return loss reflected by the return parameter corresponding to the first configuration is greater than that of the second configuration, determining the optimal configuration from the second configuration and other configurations having the same impedance value change trend as the second configuration relative to the first configuration; If the return loss reflected by the return parameter corresponding to the first configuration is smaller than that of the second configuration, the optimal configuration is determined from the first configuration and other configurations having an opposite impedance value change trend to that of the second configuration relative to the first configuration; wherein, The second frequency interval is divided by the frequency value corresponding to the first configuration, within the first frequency interval, according to a change trend of the second configuration opposite to that of the first configuration.

2. The control method according to claim 1, further comprising: include: Parameter determination step: determining a termination parameter threshold for completing heating according to the optimal configuration; Heating termination step: when the corresponding parameter reaches the termination parameter threshold, the electromagnetic wave generating module is controlled to stop generating the electromagnetic wave signal.

3. The control method according to claim 2, in, The termination parameter is the total heating time, the change rate of the return loss S11, the change rate of the forward power, or the change rate of the reverse power.

4. The control method according to claim 1, in, After the impedance matching step, the control method further includes: Echo inspection step: obtaining an echo parameter reflecting the echo loss, wherein the echo parameter is an echo loss S11 coefficient; Matching correction step: when the echo parameter is greater than a preset upper threshold, readjusting the configuration of the matching module and the frequency of the electromagnetic wave signal.

5. The control method according to claim 4, in, In the matching correction step, based on the current configuration of the matching module, the frequency value of the minimum echo parameter is determined within a frequency range less than the previous frequency; if the minimum echo parameter is less than or equal to the upper limit threshold, the electromagnetic wave generating module is controlled to generate an electromagnetic wave signal according to the frequency value of the minimum echo parameter; if the minimum echo parameter is greater than the upper limit threshold, the configuration of the matching module is adjusted to a corresponding impedance value greater than the current configuration and closest to the current configuration, and based on the configuration, a new frequency value of the minimum echo parameter is determined within a frequency range less than the previous minimum echo parameter frequency value, until the new minimum echo parameter is less than or equal to the upper limit threshold.

6. The control method according to claim 4, further comprising: include: Parameter determination step: determining a termination parameter threshold for completing heating according to the optimal configuration; Heating termination step: when the corresponding parameter reaches the termination parameter threshold, controlling the electromagnetic wave generating module to stop generating the electromagnetic wave signal; in The termination parameter is the return loss S11 change rate, the forward power change rate, or the reverse power change rate; and When the corresponding parameter reaches the termination parameter threshold and the echo parameter is greater than the upper limit threshold, the matching correction step is performed.

7. The control method according to claim 1, in, If the optimal frequency is less than a preset frequency threshold, the electromagnetic wave generating module is controlled to stop generating the electromagnetic wave signal.

8. A heating device, It is characterized in that include: Cavity capacitor, used to place the object to be processed; An electromagnetic wave generating module, configured to generate an electromagnetic wave signal for heating the object to be processed in the cavity capacitor; a matching module, connected in series between the electromagnetic wave generating module and the cavity capacitor, and comprising a plurality of matching branches connected in parallel, for reducing the return loss of the electromagnetic wave generating module; and A controller configured to execute the control method described in any one of claims 1 to 7; wherein The electromagnetic wave generating module is provided with a voltage-controlled oscillator for adjusting the frequency of the electromagnetic wave signal.

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