Control method for a heating device and heating device

Abstract

This invention provides a control method and a heating device for a heating apparatus. The heating apparatus includes a cylinder for placing a food item to be processed and an electromagnetic wave generating system for generating electromagnetic wave signals for heating the food item. The control method includes: a frequency matching step: at preset time intervals, controlling the electromagnetic wave generating system to adjust the frequency of the electromagnetic wave signal it generates within a preset selected frequency range, and ensuring that the electromagnetic wave generating system meets preset matching conditions; a change calculation step: recording the frequency of the electromagnetic wave signal that meets the preset matching conditions each time, and calculating the change in the frequency of the electromagnetic wave signal that meets the preset matching conditions from a preset number of matching attempts to the current time; and a heating termination step: controlling the electromagnetic wave generating system to stop working when any one of the preset termination conditions is met; the preset termination conditions include a change amount less than or equal to a preset change threshold, which allows the heating of food to stop in the user's desired state, and is particularly suitable for food defrosting.

Description

Technical Field

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

[0002] During the freezing process, the quality of food is preserved; however, frozen food needs to be thawed before processing or consumption. To facilitate thawing, electromagnetic wave heating devices are typically used.

[0003] Thawing food using electromagnetic wave heating devices is not only fast and efficient, but also results in minimal loss of nutrients. However, how to stop heating the food at the desired state when it is already at a high temperature has been a technical problem that those skilled in the art have been trying to solve. In existing technologies, the completion of thawing is determined by the rate of change of S11. However, due to the high heating efficiency of electromagnetic waves, the temperature of the food changes very rapidly, and even slight changes in certain external factors (such as frequency) can cause rapid changes in S11, leading to a high error rate. Summary of the Invention

[0004] One objective of the first aspect of the present invention is to provide a control method for an electromagnetic wave heating device, which employs a new heating termination condition to determine whether heating is complete.

[0005] A further objective of the first aspect of the present invention is to shorten the frequency matching time and the change calculation time.

[0006] Another further object of the first aspect of the invention is to stop heating more precisely.

[0007] A second aspect of the present invention is to provide an electromagnetic wave heating device.

[0008] According to a first aspect of the present invention, a control method for a heating device is provided, the heating device comprising a cylinder for placing a workpiece and an electromagnetic wave generating system for generating an electromagnetic wave signal for heating the workpiece, wherein the control method comprises:

[0009] Frequency matching step: At each preset time interval, the electromagnetic wave generating system is controlled to adjust the frequency of the electromagnetic wave signal it generates within a preset selected frequency range, and the electromagnetic wave generating system meets the preset matching conditions.

[0010] Change calculation steps: Record the frequency of the electromagnetic wave signal that meets the preset matching condition each time, and calculate the change in the frequency of the electromagnetic wave signal that meets the preset matching condition from the preset number of matching times to the current time.

[0011] Heating termination step: When any one of the preset termination conditions is met, the electromagnetic wave generating system is controlled to stop working; wherein,

[0012] The preset termination condition includes the change amount being less than or equal to a preset change threshold.

[0013] Optionally, in the frequency matching step, the minimum value of the preset selected frequency range to the frequency of the electromagnetic wave signal that previously met the preset matching condition is used as the candidate frequency range for this frequency matching step; and

[0014] In the change calculation step, the difference between the frequency of the electromagnetic wave signal that satisfies the preset matching condition before the preset number of matching attempts and the frequency of the electromagnetic wave signal that satisfies the preset matching condition in the current attempt is used as the change.

[0015] Optionally, in the change calculation step, the frequency difference between every two adjacent electromagnetic wave signals that satisfy the preset matching condition is calculated, and then all the differences are added together to obtain the change.

[0016] Optionally, when performing the frequency matching step for the first time, the preset matching condition includes the minimum power of the reflected wave signal returned by the electromagnetic wave generating system.

[0017] Optionally, after performing the frequency matching step for the first time, the method further includes:

[0018] Time determination step: Based on the frequency of the electromagnetic wave signal that first meets the preset matching conditions, determine the remaining heating time for the object to be processed according to a preset lookup table; wherein,

[0019] The lookup table records the correspondence between frequency and remaining heating time; and

[0020] The preset termination condition also includes that the heating time of the object to be processed after the time determination step is greater than or equal to the remaining heating time.

[0021] Optionally, when performing the frequency matching step for the first time and within a preset number of matching attempts after the first time, the preset matching condition includes minimizing the power of the reflected wave signal returning from the electromagnetic wave generating system; and after performing the frequency matching step for the preset number of matching attempts, the control method further includes:

[0022] Time determination step: Based on the sum of the frequency differences between every two adjacent electromagnetic wave signals that satisfy the preset matching conditions within the first and subsequent preset matching counts, the remaining heating time for the object to be processed is determined according to a preset lookup table; wherein,

[0023] The lookup table records the correspondence between the sum and the remaining heating time; and

[0024] The preset termination condition also includes that the heating time of the object to be processed after the time determination step is greater than or equal to the remaining heating time.

[0025] Optionally, after the time determination step, the preset matching condition includes a ratio of the power of the reflected wave signal returning to the electromagnetic wave generating system to the power of the incident wave signal propagating from the electromagnetic wave generating system to the cylinder being greater than or equal to a preset ratio threshold.

[0026] When the preset matching conditions are met, the frequency matching step ends.

[0027] Optionally, the preset number of matches is greater than or equal to 2.

[0028] Optionally, the preset time interval is 25s to 40s.

[0029] According to a second aspect of the present invention, a heating device is provided, characterized in that it comprises:

[0030] A cylindrical container used to hold the items to be processed;

[0031] An electromagnetic wave generating system is configured to generate electromagnetic wave signals for heating the object to be processed; and

[0032] The controller is configured to perform any of the control methods described above.

[0033] The inventors of this application have creatively recognized that the change in frequency that achieves matching within the same time period is relatively small, and only shows a significant decrease when approaching the phase transition region of water, and is almost affected by the degree of frequency matching. By using the change in frequency that meets the frequency matching condition as the condition for determining whether to stop heating, the determination of whether to stop heating is particularly accurate, and the heating of food can be stopped at the state desired by the user. It is particularly suitable for food defrosting, and can prevent the food to be processed from being over-frozen. The temperature when defrosting is completed is generally -4 to -2°C, which can avoid the production of blood water when the food to be processed is meat, and makes it easier for the user to cut.

[0034] Furthermore, in the frequency matching step and the change calculation step, the present invention uses the minimum value of the pre-selected frequency range to the frequency of the electromagnetic wave signal that previously met the preset matching conditions as the candidate frequency range for the current frequency matching step, and uses the difference between the frequency of the electromagnetic wave signal that met the preset matching conditions before the preset number of matching steps and the frequency of the electromagnetic wave signal that met the preset matching conditions in the current step as the change. This allows for the rapid and accurate determination of the frequency of the electromagnetic wave signal that meets the preset matching conditions, shortens the running time of the frequency matching step and the change calculation step, thereby reducing the impact of the frequency matching process on the quality of the processed material and improving the timeliness of determining whether the heating termination conditions are met.

[0035] Furthermore, in addition to using the frequency change amount that satisfies the frequency matching condition as the condition for determining the termination of heating, the present invention also adds the remaining heating time determined by the frequency that first satisfies the preset matching condition or the frequency change amount that satisfies the preset matching condition several times as the condition for determining the termination of heating. This further improves the accuracy of determining whether to stop heating, further ensures that the processed object after heating has excellent quality, and improves the user experience.

[0036] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0037] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0038] Figure 1 This is a schematic structural diagram of a heating device according to an embodiment of the present invention;

[0039] Figure 2 yes Figure 1 A schematic structural diagram of the controller;

[0040] Figure 3 This is a schematic flowchart of a control method for a heating device according to an embodiment of the present invention;

[0041] Figure 4 This is a schematic detailed flowchart of a control method for a heating device according to an embodiment of the present invention;

[0042] Figure 5 This is a schematic detailed flowchart of a control method for a heating device according to another embodiment of the present invention. Detailed Implementation

[0043] Figure 1 This is a schematic structural diagram of a heating device 100 according to an embodiment of the present invention. See also... Figure 1 The heating device 100 may include a cylinder 110, a door, an electromagnetic wave generating system, and a controller 140.

[0044] Specifically, the cylinder 110 can be used to contain the object to be processed 150. The door can be used to open and close the loading and unloading port of the cylinder 110. The cylinder 110 and the door can be provided with electromagnetic shielding features to reduce electromagnetic leakage.

[0045] The cylinder 110 may be made of metal and may be grounded to further improve the safety performance of the heating device 100.

[0046] The electromagnetic wave generating system may be at least partially disposed within or reach the cylinder 110 to emit electromagnetic waves into the cylinder 110 to heat the object to be treated 150.

[0047] The electromagnetic wave generating system may include an electromagnetic wave generating module 120, a radiating antenna 130 electrically connected to the electromagnetic wave generating module 120, and a power supply for supplying power to the electromagnetic wave generating module 120.

[0048] The electromagnetic wave generating module 120 can be configured to generate electromagnetic wave signals, and the radiating antenna 130 can be disposed inside the cylinder 110 to generate electromagnetic waves inside the cylinder 110, thereby heating the object to be processed 150 inside the cylinder 110. The electromagnetic wave generating module 120 may include a variable frequency source and a power amplifier.

[0049] Figure 2 yes Figure 1 A schematic structural diagram of the controller 140. See also... 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, which, when executed by the processing unit 141, is used to implement the control method of the embodiments of the present invention.

[0050] Specifically, the processing unit 141 can be configured to control the electromagnetic wave generating system to adjust the frequency of the electromagnetic wave signal it generates within a preset selected frequency range every preset time interval t, so that the electromagnetic wave generating system meets the preset matching conditions, record the frequency of the electromagnetic wave signal that meets the preset matching conditions each time, and calculate the change in the frequency of the electromagnetic wave signal that meets the preset matching conditions from the preset number of matching times to the current time. When the change is less than or equal to the preset change threshold S, the electromagnetic wave generating system is controlled to stop working.

[0051] The heating device 100 of the present invention controls the electromagnetic wave generating system to stop working when the frequency change that meets the frequency matching condition is less than or equal to the preset change threshold S. This allows the heating of food to stop at the state desired by the user, and is particularly suitable for food defrosting. It can prevent the food to be processed 150 from being over-frozen. The temperature when defrosting is completed is generally -4 to -2°C, which can avoid the production of blood water when the food to be processed 150 is meat, making it easier for the user to cut.

[0052] In this invention, the preset time interval t can be 25s to 40s, for example, 25s, 30s, or 40s, to avoid misjudgment.

[0053] The alternative frequency range can be 400MHz to 500MHz to ensure the temperature uniformity of the object to be processed 150 and the heating efficiency of the object to be processed 150.

[0054] The preset number of matching attempts can be greater than or equal to 2, for example, 3, to avoid misjudgments. The preset number of matching attempts can also be 1, where the change is the frequency difference between two consecutive electromagnetic wave signals that meet the preset matching conditions.

[0055] During frequency matching, the power of the electromagnetic wave signal can be 5% to 10% of the power of the electromagnetic wave signal during normal heating, so as to reduce the adverse effects on the object to be treated 150.

[0056] In some embodiments, the processing unit 141 may be configured to take the minimum value of the preset selected frequency range to the frequency of the electromagnetic wave signal that previously met the preset matching conditions as the candidate frequency range for this frequency matching, and calculate the difference between the frequency of the electromagnetic wave signal that met the preset matching conditions before the preset number of matchings and the frequency of the electromagnetic wave signal that met the preset matching conditions in this time as the change amount, so as to quickly and accurately determine the frequency of the electromagnetic wave signal that meets the preset matching conditions, thereby reducing the impact of the frequency matching process on the quality of the workpiece 150 to be processed and improving the timeliness of judging whether to stop heating.

[0057] In other embodiments, the processing unit 141 may be configured to first calculate the frequency difference (absolute value) of every two adjacent electromagnetic wave signals that meet the preset matching conditions, and then add all the differences to obtain the change, so as to improve accuracy.

[0058] In some embodiments, during the initial frequency matching, the matching condition may be: the power of the reflected wave signal from the returning electromagnetic wave generating system is minimized, so as to facilitate subsequent frequency matching and shorten the time for subsequent frequency matching.

[0059] The processing unit 141 can be configured to determine the remaining heating time T of the workpiece 150 according to a preset lookup table based on the frequency of the electromagnetic wave signal that first meets the preset matching conditions, and to control the electromagnetic wave generating system to stop working when the heating time of the workpiece 150 continues to be greater than or equal to the determined remaining heating time T, so as to further ensure that the workpiece 150 after heating has excellent quality. The lookup table records the correspondence between different frequencies and the remaining heating time T.

[0060] In other embodiments, when frequency matching is performed for the first time and within a preset number of matching times after the first time, the matching condition can be: the power of the reflected wave signal returning to the electromagnetic wave generating system is the minimum.

[0061] The processing unit 141 can be configured to determine the remaining heating time T of the workpiece 150 according to a preset lookup table based on the sum of the absolute values ​​of the frequency differences between every two adjacent electromagnetic wave signals that meet the preset matching conditions within a preset number of matching attempts after the first attempt. If the heating time of the workpiece 150 continues to be greater than or equal to the determined remaining heating time T, the electromagnetic wave generating system is controlled to stop operating, thereby more precisely stopping the heating of the workpiece 150 and further ensuring that the heated workpiece 150 has excellent quality. The lookup table records the correspondence between different sums of frequency differences and the remaining heating time T.

[0062] In some further embodiments, after determining the remaining heating time T, the matching condition may be: the ratio of the power of the reflected wave signal returning to the electromagnetic wave generating system to the power of the incident wave signal propagating from the electromagnetic wave generating system to the cylinder 110 is greater than or equal to a preset ratio threshold. The preset ratio threshold may be 70% to 80%.

[0063] When the ratio of the power of the reflected wave signal to the power of the incident wave signal is greater than or equal to a preset ratio threshold, the frequency matching ends to reduce the adverse effects on the object to be processed 150 and improve heating efficiency.

[0064] Figure 3 This is a schematic flowchart of a control method for a heating device 100 according to an embodiment of the present invention. See also Figure 3 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:

[0065] Frequency matching step (S302): Every preset time interval t, the electromagnetic wave generating system is controlled to adjust the frequency of the electromagnetic wave signal it generates within a preset selected frequency range, and the electromagnetic wave generating system meets the preset matching conditions.

[0066] Change calculation step (S304): Record the frequency of the electromagnetic wave signal that meets the preset matching conditions each time, and calculate the change in the frequency of the electromagnetic wave signal that meets the preset matching conditions from the preset number of matching times to the current time.

[0067] Heating termination step (S306): When any one of the preset termination conditions is met, the electromagnetic wave generating system is controlled to stop working; wherein, the preset termination conditions include the change amount being less than or equal to the preset change threshold S.

[0068] The control method of the present invention controls the electromagnetic wave generating system to stop working when the frequency change that meets the frequency matching condition is less than or equal to the preset change threshold S. This allows the heating of food to stop at the state desired by the user, and is particularly suitable for food thawing. It can prevent the food to be processed 150 from being over-thawed. The temperature when thawing is completed is generally -4 to -2°C, which can avoid the production of blood water when the food to be processed 150 is meat, making it easier for the user to cut.

[0069] In the frequency matching step (S302), the preset time interval t can be 25s to 40s, for example, 25s, 30s, or 40s, to avoid misjudgment. The alternative frequency range can be 400MHz to 500MHz to ensure the temperature uniformity of the object to be processed 150 and the heating efficiency of the object to be processed 150.

[0070] In the change calculation step (S304), the preset matching number can be greater than or equal to 2, for example, 3, to avoid misjudgment. The preset matching number can also be 1, that is, the change is the difference in frequency between two adjacent electromagnetic wave signals that meet the preset matching conditions.

[0071] In the frequency matching step (S302), the power of the electromagnetic wave signal can be 5% to 10% of the power of the electromagnetic wave signal in other steps, so as to reduce the adverse effects on the object to be processed 150.

[0072] In some embodiments, in the frequency matching step (S302), the minimum value of the pre-selected frequency range to the frequency of the electromagnetic wave signal that previously met the preset matching conditions can be used as the candidate frequency range for this frequency matching step, that is, a new candidate frequency range is determined in the pre-selected frequency range, thereby shortening the running time of the frequency matching step (S302).

[0073] In the change calculation step (S304), the difference between the frequency of the electromagnetic wave signal that meets the preset matching conditions before the preset number of matching times and the current frequency can be calculated as the change, so as to shorten the change calculation time and improve the timeliness of stopping the heating of the object to be processed 150.

[0074] In other embodiments, in the change calculation step (S304), the difference (absolute value) of the frequencies of every two adjacent electromagnetic wave signals that meet the preset matching conditions can be calculated first, and then all the differences can be added together to obtain the change, so as to improve accuracy.

[0075] In some embodiments, when performing the frequency matching step (S302) for the first time, the matching condition may be: the power of the reflected wave signal from the returning electromagnetic wave generating system is the minimum, so as to facilitate subsequent frequency matching and shorten the time of subsequent frequency matching.

[0076] The control method of the present invention may further include a time determination step: determining the remaining heating time T of the object to be processed 150 according to a preset lookup table based on the frequency of the electromagnetic wave signal that first meets the preset matching conditions. The lookup table records the correspondence between different frequencies and the remaining heating time T.

[0077] The preset termination condition may also include that the heating time of the workpiece 150 after the time determination step is greater than or equal to the determined remaining heating time T. That is, when the frequency change that meets the frequency matching condition is less than or equal to the preset change threshold S, or when the heating time of the workpiece 150 is greater than or equal to the determined remaining heating time T, the electromagnetic wave generation system is controlled to stop working, so as to further ensure that the workpiece 150 after heating has excellent quality.

[0078] In other embodiments, when performing the frequency matching step (S302) for the first time and within a preset number of matching times after the first time, the matching condition can be: the power of the reflected wave signal from the returning electromagnetic wave generating system is the minimum.

[0079] The control method of the present invention may further include a time determination step: determining the remaining heating time T of the object to be processed 150 according to a preset lookup table based on the sum of the absolute values ​​of the frequency differences between every two adjacent electromagnetic wave signals that meet the preset matching conditions within the first and subsequent preset matching counts. The lookup table records the correspondence between different sums of differences and the remaining heating time T.

[0080] The preset termination condition may also include that the heating time of the workpiece 150 after the time determination step is greater than or equal to the determined remaining heating time T. That is, when the frequency change that meets the frequency matching condition is less than or equal to the preset change threshold S, or when the heating time of the workpiece 150 is greater than or equal to the determined remaining heating time T, the electromagnetic wave generation system is controlled to stop working, so as to more accurately stop the heating of the workpiece 150 and further ensure that the heated workpiece 150 has excellent quality.

[0081] In some further embodiments, after the time determination step, the matching condition may be: the ratio of the power of the reflected wave signal returning to the electromagnetic wave generating system to the power of the incident wave signal propagating from the electromagnetic wave generating system to the cylinder 110 is greater than or equal to a preset ratio threshold. The preset ratio threshold may be 70% to 80%.

[0082] When the ratio of the power of the reflected wave signal to the power of the incident wave signal is greater than or equal to a preset ratio threshold, the frequency matching ends to reduce the adverse effects on the object to be processed 150 and improve heating efficiency.

[0083] Figure 4This is a schematic detailed flowchart of a control method for a heating device 100 according to an embodiment of the present invention (in... Figure 4 and Figure 5 In the text, "Y" indicates "yes"; "N" indicates "no". See also... Figure 4 The control method for the heating device 100 according to one embodiment of the present invention may include the following detailed steps:

[0084] Step S402: Obtain heating command.

[0085] Step S404: Control the electromagnetic wave generating system to adjust the frequency of the electromagnetic wave signal it generates within the preset selected frequency range, and make the electromagnetic wave generating system meet the preset matching conditions, and record the frequency f1 of the electromagnetic wave signal that meets the preset matching conditions.

[0086] Step S406: Determine the remaining heating time T of the object to be processed 150 according to the frequency f1 and a preset lookup table. The lookup table records the correspondence between different frequencies and the remaining heating time T.

[0087] Step S408: Determine whether the heating time of the workpiece 150 after step S406 is greater than or equal to the determined remaining heating time T. If yes, proceed to step S414; if no, proceed to step S410.

[0088] Step S410: After each preset time interval t, control the electromagnetic wave generating system to adjust the frequency of the electromagnetic wave signal it generates within a preset selected frequency range, and ensure that the electromagnetic wave generating system meets the preset matching conditions. Record the frequency f of the electromagnetic wave signal that meets the preset matching conditions. n .

[0089] Step S412: Determine Δf n , Δf n-1 ... and Δf n-k Is the sum less than or equal to the preset change threshold S? If yes, proceed to step S414; otherwise, return to step S408. Where Δf n =f n-1 -f n n represents the frequency of this match; k is the preset number of matches.

[0090] Step S414: Control the electromagnetic wave generating system to stop working.

[0091] Figure 5 This is a schematic detailed flowchart of a control method for a heating device 100 according to another embodiment of the present invention. See also Figure 5 Another embodiment of the control method for the heating device 100 of the present invention may include the following detailed steps:

[0092] Step S502: Obtain heating command.

[0093] Step S504: Control the electromagnetic wave generating system to adjust the frequency of the electromagnetic wave signal it generates within the preset selected frequency range, and make the electromagnetic wave generating system meet the preset matching conditions, and record the frequency f1 of the electromagnetic wave signal that meets the preset matching conditions.

[0094] Step S506: After a preset time interval t, control the electromagnetic wave generating system to adjust the frequency of the electromagnetic wave signal it generates within a preset selected frequency range, and make the electromagnetic wave generating system meet the preset matching conditions, and record the frequency f2 of the electromagnetic wave signal that meets the preset matching conditions.

[0095] Step S508: After each preset time interval t, control the electromagnetic wave generating system to adjust the frequency of the electromagnetic wave signal it generates within a preset selected frequency range, and ensure that the electromagnetic wave generating system meets the preset matching condition until the (k+1)th frequency matching, and record the frequency f of the electromagnetic wave signal that meets the preset matching condition. k+1 Where k is the preset number of matches.

[0096] Step S510: Determine Δf k+1 , Δf k Is the sum of f1, f2, ..., and Δf2 less than or equal to the preset change threshold S? If yes, proceed to step S520; otherwise, return to step S512. Wherein, Δf... k+1 =f k -f k+1 .

[0097] Step S512: Based on Δf k+1 , Δf k The sum of , ..., and Δf2 determines the remaining heating time T of the object to be treated 150 according to a preset lookup table. The lookup table records the correspondence between the sum of different differences and the remaining heating time T.

[0098] Step S514: Determine whether the heating time of the workpiece 150 after step S512 is greater than or equal to the determined remaining heating time T. If yes, proceed to step S520; if no, proceed to step S516.

[0099] Step S516: After each preset time interval t, control the electromagnetic wave generating system to adjust the frequency of the electromagnetic wave signal it generates within a preset selected frequency range, and ensure that the electromagnetic wave generating system meets the preset matching conditions. Record the frequency f of the electromagnetic wave signal that meets the preset matching conditions. n Where n represents the frequency matching in this instance.

[0100] Step S518: Determine Δf n , Δf n-1 ... and Δfn-k Is the sum less than or equal to the preset change threshold S? If yes, proceed to step S520; otherwise, return to step S514. Where Δf n =f n-1 -f n .

[0101] Step S520: Control the electromagnetic wave generating system to stop working.

[0102] Therefore, those skilled in the art should recognize that although numerous exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Thus, the scope of the present invention should be understood and construed as covering all such other variations or modifications.

Claims

1. A control method for a heating device, the heating device comprising a cylinder for holding a material to be processed, and an electromagnetic wave generating system for generating an electromagnetic wave signal for heating the material to be processed, wherein, The control method includes: Frequency matching step: At each preset time interval, the electromagnetic wave generating system is controlled to adjust the frequency of the electromagnetic wave signal it generates within a preset selected frequency range, and the electromagnetic wave generating system meets the preset matching conditions. Change calculation steps: Record the frequency of the electromagnetic wave signal that meets the preset matching condition each time, and calculate the change in the frequency of the electromagnetic wave signal that meets the preset matching condition from the preset number of matching times to the current time. Heating termination step: When any one of the preset termination conditions is met, the electromagnetic wave generating system is controlled to stop working; wherein, The preset termination condition includes the change amount being less than or equal to a preset change threshold; and In the change calculation step, the frequency difference between any two adjacent electromagnetic wave signals that meet the preset matching conditions is calculated, and then all the differences are added together to obtain the change.

2. The control method according to claim 1, wherein, When the frequency matching step is performed for the first time, the preset matching condition includes that the power of the reflected wave signal returned by the electromagnetic wave generating system is the minimum.

3. The control method according to claim 2, wherein, Following the initial execution of the frequency matching step, the following is also included: Time determination step: Based on the frequency of the electromagnetic wave signal that first meets the preset matching conditions, determine the remaining heating time for the object to be processed according to a preset lookup table; wherein, The lookup table records the correspondence between frequency and remaining heating time; and The preset termination condition also includes that the heating time of the object to be processed after the time determination step is greater than or equal to the remaining heating time.

4. The control method according to claim 1, wherein, When the frequency matching step is performed for the first time and within a preset number of matching attempts after the first time, the preset matching condition includes minimizing the power of the reflected wave signal returning from the electromagnetic wave generating system; and after the frequency matching step is performed for the preset number of matching attempts, the control method further includes: Time determination step: Based on the sum of the frequency differences between every two adjacent electromagnetic wave signals that satisfy the preset matching conditions within the first and subsequent preset matching counts, the remaining heating time for the object to be processed is determined according to a preset lookup table; wherein, The lookup table records the correspondence between the sum and the remaining heating time; and The preset termination condition also includes that the heating time of the object to be processed after the time determination step is greater than or equal to the remaining heating time.

5. The control method according to claim 3 or 4, wherein, After the time determination step, the preset matching condition includes a ratio of the power of the reflected wave signal returning to the electromagnetic wave generating system to the power of the incident wave signal propagating from the electromagnetic wave generating system to the cylinder being greater than or equal to a preset ratio threshold. When the preset matching conditions are met, the frequency matching step ends.

6. The control method according to claim 1, wherein, The preset number of matches is greater than or equal to 2.

7. The control method according to claim 1, wherein, The preset time interval is 25s to 40s.

8. A heating device, characterized in that, include: A cylindrical container used to hold the items to be processed; An electromagnetic wave generating system is configured to generate electromagnetic wave signals for heating the object to be processed; as well as A controller configured to perform the control method as described in any one of claims 1-7.

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