Control method for a heating device and heating device

Abstract

The application provides a control method for a heating device and the heating device. The heating device comprises a cavity for placing a to-be-processed object and an electromagnetic wave generating system for generating electromagnetic waves in the cavity to heat the to-be-processed object. The control method comprises: a frequency matching step, if a preset frequency adjustment condition is met, the electromagnetic wave generating system is controlled to adjust the frequency of the generated electromagnetic waves to meet a preset matching condition; and a power adjustment step, if the cumulative frequency difference of the frequency adjustment of any one or more times within a preset number of times in the frequency matching step is greater than a first frequency difference threshold, the electromagnetic wave generating system is controlled to reduce the power of the generated electromagnetic waves, which can effectively avoid the hotspot part from continuing to heat up quickly, improve the temperature uniformity of the to-be-processed object, and is particularly suitable for food thawing.

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 improve thawing efficiency and ensure thawing quality, electromagnetic wave heating devices are typically used to thaw food.

[0003] However, due to the irregular shape and uneven distribution of substances in food, hot spots (local overheating) are easily formed during the thawing process. As the thawing time increases, the temperature difference between different parts of the food will continue to intensify. Some parts of the food will be over-thawed and softened, while others will remain frozen, which seriously affects the user experience. Summary of the Invention

[0004] One objective of the first aspect of the present invention is to overcome at least one technical defect in the prior art and provide a control method for a heating device.

[0005] A further objective of the first aspect of the present invention is to improve the temperature uniformity of the material to be treated.

[0006] Another further objective of the first aspect of the present invention is to improve the energy efficiency ratio of the heating device.

[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 cavity for placing a workpiece and an electromagnetic wave generating system for generating electromagnetic waves within the cavity to heat the workpiece, wherein the control method comprises:

[0009] Frequency matching step: If the preset frequency tuning conditions are met, the electromagnetic wave generating system is controlled to adjust the frequency of the electromagnetic waves it generates in order to meet the preset matching conditions.

[0010] Power adjustment step: If the cumulative frequency difference of any one or more frequency adjustments within the preset number of times in the frequency matching step is greater than the first frequency difference threshold, the electromagnetic wave generating system is controlled to reduce the power of the electromagnetic wave it generates.

[0011] Optionally, the method further includes the following steps before the frequency matching step:

[0012] Time determination step: Determine the remaining heating time of the object to be processed; and

[0013] The following steps are included after the power regulation step:

[0014] Time correction step: Extend the remaining heating time.

[0015] Optionally, the reduction ratio of the electromagnetic wave power in the power adjustment step is less than the extension ratio of the remaining heating time in the time correction step.

[0016] Optionally, in the power adjustment step, the power of the electromagnetic wave is reduced by 20% to 40%; and / or

[0017] In the time correction step, the remaining heating time is extended by 35% to 55%.

[0018] Optionally, the control method further includes:

[0019] Special termination step: If the cumulative frequency difference of the preset number of frequency adjustments in the frequency matching step is less than the second frequency difference threshold, the electromagnetic wave generating system is controlled to immediately stop working or continue working for a preset time before stopping working; wherein,

[0020] The second frequency difference threshold is less than the first frequency difference threshold.

[0021] Optionally, the method further includes the following steps before the frequency matching step:

[0022] Initial frequency determination step: Determine the initial frequency for heating the object to be processed based on the reflection parameters of the electromagnetic wave generating system;

[0023] Threshold determination step: Determine the first frequency difference threshold and the second frequency difference threshold based on the initial frequency; wherein,

[0024] The first frequency difference threshold and the second frequency difference threshold are positively correlated with the initial frequency.

[0025] Optionally, the initial frequency determination step further includes:

[0026] Reference frequency determination steps: Control the electromagnetic wave generating system to adjust the frequency of the electromagnetic wave it generates within a preset candidate frequency range according to a preset first step length, obtain the reflection parameters corresponding to each frequency generated by the electromagnetic wave generating system, and determine the reference frequency based on the reflection parameters.

[0027] The optimal frequency determination step involves controlling the electromagnetic wave generating system to adjust the frequency of the generated electromagnetic waves within a selected frequency range according to a preset second step size, obtaining the reflection parameters corresponding to each frequency generated by the electromagnetic wave generating system, and determining the optimal frequency as the initial frequency based on the reflection parameters; wherein,

[0028] The selected frequency range is based on the reference frequency and is within a range of frequencies with the absolute value of the first step length as the radius; and

[0029] The absolute value of the second step length is less than the absolute value of the first step length.

[0030] Optionally, in the frequency matching step, the single frequency difference before and after frequency adjustment is calculated, and the single frequency difference of the most recent preset number of times is stored; and

[0031] The cumulative frequency difference is the sum of the single frequency differences for the corresponding number of times.

[0032] Optionally, if, during the frequency matching step, each frequency generated by the electromagnetic wave generating system does not meet the preset matching condition, the electromagnetic wave generating system is controlled to generate electromagnetic waves with frequencies equal to the minimum value of a preset candidate frequency range.

[0033] According to a second aspect of the present invention, a heating device is provided, comprising:

[0034] A cavity, used to hold the object to be processed;

[0035] An electromagnetic wave generating system for generating electromagnetic waves within the cavity to heat the object to be processed; and

[0036] The controller is configured to perform any of the control methods described above.

[0037] This invention determines whether a hot spot appears on the object to be processed by the cumulative frequency difference of any one or more frequency adjustments within a preset number of steps in the frequency matching process. When the cumulative frequency difference is greater than a first frequency difference threshold, the electromagnetic wave generating system is controlled to reduce the power of the electromagnetic waves it generates. This can effectively prevent the hot spot from continuing to heat up rapidly and improve the temperature uniformity of the object to be processed. It is particularly suitable for food defrosting.

[0038] The inventors of this application have creatively recognized that during the food thawing process, when hot spots appear in a localized area of ​​the food, the hot spot will change from ice to water. Since the dielectric constant of water is much greater than that of ice, the resonant frequency of the cavity will change significantly in a short period of time. By using the cumulative frequency difference of any one or more frequency adjustments within a preset number of times, it is possible to accurately determine whether hot spots have appeared in the food to be processed, without the need to add temperature sensors or other sensing elements, thus reducing production costs.

[0039] Furthermore, the present invention sets the extension ratio of the remaining heating time in the time correction step to be greater than the reduction ratio of the power in the power adjustment step, so as to avoid the occurrence of uneven temperature inside and outside the object to be processed due to the change in the penetration ability of electromagnetic waves. While improving the temperature uniformity, it makes the heating of the object to be processed stop at the state expected by the user, thus overcoming the constraint of the idea that the same work can make the object to be processed reach the same state in the prior art.

[0040] Furthermore, the present invention determines a first frequency difference threshold and a second frequency difference threshold based on the initial frequency. When the cumulative frequency difference of frequency adjustment within a preset number of times in the frequency matching step is less than the second frequency difference threshold, the electromagnetic wave generating system is controlled to immediately stop working or continue working for a preset time before stopping working. This allows for accurate determination of whether hot spots have appeared in different types and sizes of the objects to be processed, improving the applicability of the heating device. It also allows for timely stopping of heating when the food has been thawed or when the heating device malfunctions, preventing the food from being overheated and improving the safety of the heating device.

[0041] Furthermore, this invention first uses a larger step size to search and determine a reference frequency to represent the approximate position of the optimal frequency, and then uses a smaller step size to search and determine the optimal frequency near the reference frequency as the initial frequency. Compared with the prior art method of determining the optimal frequency by traversing all frequencies, this invention can improve the efficiency of determining the optimal frequency by several times, thereby reducing the total heating time, reducing unnecessary energy consumption, and improving the energy efficiency ratio of the heating device.

[0042] 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

[0043] The following sections will describe some specific embodiments of the invention in a detailed manner 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:

[0044] Figure 1 This is a schematic structural diagram of a 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 This is a schematic flowchart of a control method for a heating device according to an embodiment of the present invention;

[0047] Figure 4This is a schematic detailed flowchart of a control method for a heating device according to an embodiment of the present invention. Detailed Implementation

[0048] 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 cavity 110, an electromagnetic wave generating system, and a controller 140.

[0049] The cavity 110 may include a cylinder and a door. The cylinder can be used to place the object to be processed 150. The door can be used to open and close the loading and unloading port of the cylinder.

[0050] The cylinder and door may be equipped with electromagnetic shielding features to reduce electromagnetic leakage. The cylinder may be made of metal and grounded.

[0051] The electromagnetic wave generating system may be at least partially disposed within or accessible to the cavity 110 to generate electromagnetic waves within the cavity 110, thereby heating the object to be processed 150.

[0052] 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.

[0053] The electromagnetic wave generating module 120 can be configured to generate electromagnetic wave signals. The radiating antenna 130 can be disposed within the cavity 110 to generate electromagnetic waves within the cavity 110. The electromagnetic wave generating module 120 may include a variable frequency source and a power amplifier.

[0054] 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.

[0055] The processing unit 141 can be configured to, during the heating process, if the preset frequency modulation conditions are met, control the electromagnetic wave generation module 120 to adjust the frequency of the electromagnetic wave signal it generates in order to meet the preset matching conditions and improve the heating efficiency.

[0056] The preset frequency modulation condition can be that the reflection parameter of the electromagnetic wave generating system is greater than the preset frequency modulation reflection threshold, so as to ensure heating efficiency.

[0057] The preset matching condition can be that the reflection parameters of the electromagnetic wave generating system reach a concave inflection point and the reflection parameters are less than a preset matching reflection threshold. The processing unit 141 can be configured to control the electromagnetic wave generating module 120 to generate an electromagnetic wave signal at the frequency corresponding to this inflection point, so as to further improve the heating efficiency. The matching reflection threshold can be less than the frequency modulation reflection threshold.

[0058] The reflection parameter can be the return loss S11. The reflection parameter can also be the reflected power value of the electromagnetic wave signal reflected back to the electromagnetic wave generation module 120.

[0059] Specifically, the processing unit 141 can be configured to control the electromagnetic wave generation module 120 to reduce the power of the electromagnetic wave signal it generates when the cumulative frequency difference Δf of any one or more frequency adjustments within a preset number of times is greater than the first frequency difference threshold D1 during the heating process, so as to effectively prevent the hot spot from continuing to heat up rapidly and improve the temperature uniformity of the object to be processed 150.

[0060] In some embodiments, the processing unit 141 may be configured to calculate the single frequency difference before and after frequency adjustment while controlling the electromagnetic wave generation module 120 to adjust the frequency of the electromagnetic wave signal it generates, and store the single frequency difference of the most recent preset number of times in the storage unit 142 so as to determine the cumulative frequency difference Δf of any one or more frequency adjustments in a timely manner.

[0061] The single frequency difference is the absolute value of the difference between the frequency before and after frequency adjustment. The cumulative frequency difference Δf is the sum of the single frequency differences for the corresponding number of adjustments.

[0062] In some embodiments, the processing unit 141 may be configured to determine the remaining heating time of the object to be processed 150, and if the cumulative frequency difference Δf of any one or more frequency adjustments within a preset number of times is greater than the first frequency difference threshold D1, control the electromagnetic wave generating module 120 to reduce the power of the electromagnetic wave signal it generates while extending the remaining heating time, so as to avoid incomplete heating.

[0063] In some further embodiments, if the cumulative frequency difference Δf of any one or more frequency adjustments within a preset number of times is greater than the first frequency difference threshold D1, the reduction ratio of the electromagnetic wave signal power can be less than the extension ratio of the remaining heating time, so as to improve the temperature uniformity while stopping the heating of the object to be processed 150 in the state desired by the user.

[0064] For example, the power of the electromagnetic wave signal can be reduced by 20% to 40%, such as 20%, 30%, or 40%. The remaining heating time can be extended by 35% to 55%, such as 35%, 40%, 45%, or 55%.

[0065] In some embodiments, the processing unit 141 may be configured to control the electromagnetic wave generation module 120 to generate an electromagnetic wave signal with a frequency of the minimum value of a preset candidate frequency range and stop calculating the cumulative frequency difference when the preset matching conditions are not met at each frequency, so as to ensure the heating effect.

[0066] The alternative frequency range can be 350MHz to 500MHz. Furthermore, the alternative frequency range can be 400MHz to 460MHz to further improve the temperature uniformity of the material to be processed 150.

[0067] In some embodiments, the processing unit 141 may be configured to control the electromagnetic wave generating module 120 to immediately stop working or continue working for a preset time when the cumulative frequency difference Δf of the frequency adjustment of a preset number of times is less than the second frequency difference threshold D2. This is to stop heating in a timely manner when the object to be processed 150 has been thawed or the heating device 100 malfunctions, thereby preventing the object to be processed 150 from being overheated and improving the safety of the heating device 100. The second frequency difference threshold D2 may be less than the first frequency difference threshold D1.

[0068] In some further embodiments, the processing unit 141 may be configured to determine the initial frequency of the object to be heated 150 based on the reflection parameters of the electromagnetic wave generating system at the start of heating, and to determine a first frequency difference threshold D1 and a second frequency difference threshold D2 based on the initial frequency. The first frequency difference threshold D1 and the second frequency difference threshold D2 are positively correlated with the initial frequency to accommodate objects 150 of different types and size parameters.

[0069] Processing unit 141 may be further configured to first determine a reference frequency f for searching the optimal frequency. b Then determine the optimal frequency f suitable for heating. g As an initial frequency, to improve the determination of the optimal frequency f g This improves efficiency, thereby reducing the total heating time, minimizing unnecessary energy consumption, and increasing the energy efficiency ratio of the heating device 100.

[0070] Specifically, the processing unit 141 can be configured to control the electromagnetic wave generating module 120 to adjust the frequency of the electromagnetic wave signal it generates within a preset candidate frequency range according to a preset first step length W1, acquire the reflection parameters corresponding to each frequency generated by the electromagnetic wave generating module 120, and determine the reference frequency f based on the reflection parameters. b .

[0071] Processing unit 141 can be further configured to control electromagnetic wave generation module 120 to adjust the frequency of the electromagnetic wave signal it generates within a selected frequency range according to a preset second step size W2, acquire the reflection parameters corresponding to each frequency generated by electromagnetic wave generation module 120, and determine the optimal frequency f based on the reflection parameters. gThe selected frequency range can be based on the reference frequency f. b The frequency within the radius is defined by the absolute value of the first step length W1.

[0072] The absolute value of the second step length W2 can be less than the absolute value of the first step length W1.

[0073] In some embodiments, the processing unit 141 may be configured to search for a reference frequency f in increments from the minimum value of a self-selected frequency range. b That is, the length W1 of the first step is a positive number.

[0074] In some alternative embodiments, processing unit 141 may also be configured to search for a reference frequency f by decreasing the maximum value of the self-selected frequency range. b That is, the length W1 of the first step is negative.

[0075] The absolute value of the first step length W1 can be 5MHz to 10MHz. For example, 5MHz, 7MHz, or 10MHz.

[0076] The absolute value of the second step size W2 can be 1MHz to 2MHz. For example, 1MHz, 1.5MHz, or 2MHz.

[0077] In some further embodiments, the processing unit 141 may be configured to control the electromagnetic wave generating module 120 to adjust the frequency of the electromagnetic wave signal it generates until the reflection parameter is less than a preset first reflection threshold S1, and to determine the frequency at which the reflection parameter is less than the first reflection threshold S1 as the reference frequency f. b That is, the processing unit 141 determines the frequency at which the reflection parameter first appears to be less than the first reflection threshold S1 as the reference frequency f. b In order to obtain the accurate optimal frequency f g At the same time, further improve the determination of the optimal frequency f g Efficiency.

[0078] In some further embodiments, the processing unit 141 may be configured to control the electromagnetic wave generating module 120 to stop working and issue visual and / or auditory signals to prompt the user of the fault when the reflection parameter corresponding to each frequency generated by the electromagnetic wave generating module 120 is greater than the first reflection threshold S1, so as to avoid poor heating effect and damage to the electromagnetic wave generating system.

[0079] In some further embodiments, the processing unit 141 may be configured to control the electromagnetic wave generating module 120 to adjust the frequency of the electromagnetic wave signal it generates until the reflection parameter reaches a concave inflection point, and determine the frequency corresponding to this inflection point as the optimal frequency f. g To achieve excellent heating results. Optimal frequency f gThe reflection parameters corresponding to both the previous and subsequent frequencies are greater than the optimal frequency f. g The reflection parameters (i.e., the inflection point with a concave shape).

[0080] Processing unit 141 may be further configured to first determine the reference frequency f b The search direction is shifted towards high frequency or low frequency. Further, the electromagnetic wave generation module 120 is controlled to adjust the frequency of the electromagnetic wave signal it generates until the reflection parameter reaches a concave inflection point.

[0081] In some exemplary embodiments, the processing unit 141 may be configured to acquire the frequency relative to the reference frequency f. b The frequency greater than the second step size W2 and the frequency greater than the reference frequency f b For reflection parameters with frequencies less than the second step size W2, compare the magnitudes of the two reflection parameters and determine the direction corresponding to the frequency with the smaller reflection parameter as the search direction.

[0082] In some further embodiments, the processing unit 141 may be configured to operate at an optimal frequency f. g If the corresponding reflection parameter is greater than the preset second reflection threshold S2, the electromagnetic wave generating module 120 stops working and sends a visual and / or auditory signal to indicate a fault, in order to avoid poor heating effect. The second reflection threshold S2 can be less than the first reflection threshold S1.

[0083] In some further embodiments, the processing unit 141 may be configured to operate at an optimal frequency f. g Greater than or equal to the preset minimum frequency threshold f i And less than or equal to the preset maximum frequency threshold f a In the case of optimal frequency f g Determine the remaining heating time.

[0084] The processing unit 141 can be configured to count down based on the remaining heating time, and when the remaining heating time is 0, control the electromagnetic wave generating module 120 to stop working and issue visual and / or auditory signals to indicate that heating is complete.

[0085] In some further embodiments, the processing unit 141 may be configured to operate at an optimal frequency f. g Less than the minimum frequency threshold f i In the event of an overload, the electromagnetic wave generating module 120 stops working and sends visual and / or auditory signals to indicate overload, in order to avoid excessive heating time.

[0086] Minimum frequency threshold f iThe difference between the minimum value and the minimum value of the candidate frequency range can be 15% to 30% of the difference between the maximum and minimum values ​​of the candidate frequency range. For example, 15%, 20%, 25%, or 30%.

[0087] In some further embodiments, the processing unit 141 may be configured to operate at an optimal frequency f. g Greater than the maximum frequency threshold f a In the event of an unloaded condition, the electromagnetic wave generating module 120 will stop working and issue visual and / or auditory signals to indicate that it is not in use, so as to avoid damaging the electromagnetic wave generating system.

[0088] The maximum value of the candidate frequency range and the maximum frequency threshold f a The difference can be 5% to 10% of the difference between the maximum and minimum values ​​in the candidate frequency range. For example, 5%, 7%, 8%, or 10%.

[0089] It should be noted that the heating device 100 of the present invention is particularly suitable for use in refrigerators, and the cavity 110 can be installed in a storage compartment of the refrigerator.

[0090] 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 of the present invention may include the following steps:

[0091] Frequency matching step (step S302): If the preset frequency tuning conditions are met, the electromagnetic wave generating system is controlled to adjust the frequency of the electromagnetic waves it generates in order to meet the preset matching conditions and improve heating efficiency.

[0092] Power adjustment step (step S304): If the cumulative frequency difference Δf of any one or more frequency adjustments within the preset number of times in the frequency matching step is greater than the first frequency difference threshold D1, the electromagnetic wave generating system is controlled to reduce the power of the electromagnetic waves it generates, so as to effectively prevent the hot spot from continuing to heat up rapidly and improve the temperature uniformity of the object to be processed 150.

[0093] The preset frequency modulation condition can be that the reflection parameter of the electromagnetic wave generating system is greater than the preset frequency modulation reflection threshold, so as to ensure heating efficiency.

[0094] The preset matching condition can be that the reflection parameters of the electromagnetic wave generating system reach a concave inflection point and the reflection parameters are less than a preset matching reflection threshold, so that the electromagnetic wave generating module 120 generates an electromagnetic wave signal at the frequency corresponding to that inflection point, further improving heating efficiency. The matching reflection threshold can be less than the frequency modulation reflection threshold.

[0095] The reflection parameter can be the return loss S11. The reflection parameter can also be the reflected power value of the electromagnetic wave signal reflected back to the electromagnetic wave generation module 120.

[0096] In some embodiments, the frequency matching step may further include: calculating the single frequency difference before and after frequency adjustment, and storing the single frequency difference of the most recent preset number of times, so as to determine the cumulative frequency difference Δf of any one or more frequency adjustments in a timely manner.

[0097] The single frequency difference is the absolute value of the difference between the frequency before and after frequency adjustment. The cumulative frequency difference Δf is the sum of the single frequency differences for the corresponding number of adjustments.

[0098] In some embodiments, a time determination step is included before the frequency matching step for determining the remaining heating time of the object to be treated.

[0099] The control method of the present invention may further include a time correction step. The time correction step is executed simultaneously with the power adjustment step, extending the remaining heating time based on the current remaining heating time to avoid incomplete heating.

[0100] In some further embodiments, during the power adjustment step, the reduction ratio of the electromagnetic wave signal power may be less than the extension ratio of the remaining heating time, so as to improve temperature uniformity while stopping the heating of the workpiece 150 at the user-desired state.

[0101] For example, in the power adjustment step, the power of the electromagnetic wave signal can be reduced by 20% to 40%, such as 20%, 30%, or 40%. In the time correction step, the remaining heating time can be extended by 35% to 55%, such as 35%, 40%, 45%, or 55%.

[0102] In some embodiments, if each electromagnetic wave signal generated by the electromagnetic wave generation module 120 does not meet the preset matching conditions in the frequency matching step, the electromagnetic wave generation module 120 is controlled to generate an electromagnetic wave signal with a frequency of the minimum value of the preset candidate frequency range and the calculation of the cumulative frequency difference is stopped to ensure the heating effect.

[0103] The alternative frequency range can be 350MHz to 500MHz. Furthermore, the alternative frequency range can be 400MHz to 460MHz to further improve the temperature uniformity of the material to be processed 150.

[0104] In some embodiments, the control method of the present invention may further include a special termination step. The special termination step may, in the case that the cumulative frequency difference Δf of the frequency adjustment for a preset number of times in the frequency matching step is less than a second frequency difference threshold D2, control the electromagnetic wave generating module 120 to immediately stop working or to stop working after a preset time. This ensures timely stopping of heating when the object to be processed 150 has completed thawing or the heating device 100 malfunctions, preventing overheating of the object to be processed 150 and improving the safety of the heating device 100. The second frequency difference threshold may be less than the first frequency difference threshold.

[0105] In some further embodiments, the control method of the present invention may further include an initial frequency determination step and a threshold determination step before the frequency matching step.

[0106] The initial frequency determination step determines the initial frequency of the object to be heated 150 based on the reflection parameters of the electromagnetic wave generating system at the start of heating. The threshold determination step determines a first frequency difference threshold D1 and a second frequency difference threshold D2 based on the initial frequency. The first frequency difference threshold D1 and the second frequency difference threshold D2 are positively correlated with the initial frequency to accommodate objects 150 of different types and size parameters.

[0107] The initial frequency determination step may further include a reference frequency determination step and an optimal frequency determination step, first determining a reference frequency f used to search for the optimal frequency. b Then determine the optimal frequency f suitable for heating. g As an initial frequency, to improve the determination of the optimal frequency f g This improves efficiency, thereby reducing the total heating time, minimizing unnecessary energy consumption, and increasing the energy efficiency ratio of the heating device 100.

[0108] The reference frequency determination step may include: controlling the electromagnetic wave generating module 120 to adjust the frequency of the electromagnetic wave signal it generates within a preset candidate frequency range according to a preset first step length W1; obtaining the reflection parameters corresponding to each frequency generated by the electromagnetic wave generating module 120; and determining the reference frequency f based on the reflection parameters. b .

[0109] The optimal frequency determination step may include: controlling the electromagnetic wave generating module 120 to adjust the frequency of the electromagnetic wave signal it generates within a selected frequency range according to a preset second step size W2, obtaining the reflection parameters corresponding to each frequency generated by the electromagnetic wave generating module 120, and determining the optimal frequency f based on the reflection parameters. g As the initial frequency.

[0110] The selected frequency range can be based on the reference frequency f. b The frequency is defined within a radius, with the absolute value of the first step length W1 as its value. The absolute value of the second step length W2 can be less than the absolute value of the first step length W1.

[0111] In some embodiments, when determining the reference frequency f b During the process, the minimum value of the self-selected frequency range can be incremented to search for the reference frequency f. b That is, the length W1 of the first step is a positive number.

[0112] In some alternative embodiments, when determining the reference frequency f b During the process, the maximum value of the self-selected frequency range can be decreased to search for the reference frequency f. b That is, the length W1 of the first step is negative.

[0113] The absolute value of the first step length W1 can be 5MHz to 10MHz. For example, 5MHz, 7MHz, or 10MHz.

[0114] The absolute value of the second step size W2 can be 1MHz to 2MHz. For example, 1MHz, 1.5MHz, or 2MHz.

[0115] In some further embodiments, in the optimal frequency determination step, the electromagnetic wave generating module 120 adjusts the frequency of the electromagnetic wave signal it generates until the reflection parameter is less than a preset first reflection threshold S1, and the frequency at which the reflection parameter is less than the first reflection threshold S1 is determined as the reference frequency f. b That is, the frequency at which the reflection parameter first appears to be less than the first reflection threshold S1 is determined as the reference frequency f. b In order to obtain the accurate optimal frequency f g At the same time, further improve the determination of the optimal frequency f g Efficiency.

[0116] In some further embodiments, if the reflection parameter corresponding to each frequency generated by the electromagnetic wave generating module 120 is greater than the first reflection threshold S1, the electromagnetic wave generating module 120 is controlled to stop working and emits visual and / or auditory signals to prompt the user of the fault, so as to avoid poor heating effect and damage to the electromagnetic wave generating system.

[0117] In some further embodiments, in the optimal frequency determination step, the electromagnetic wave generating module 120 adjusts the frequency of the electromagnetic wave signal it generates until the reflection parameter reaches a concave inflection point, and the frequency corresponding to this inflection point is determined as the optimal frequency f. g To achieve excellent heating results. Optimal frequency f g The reflection parameters corresponding to both the previous and subsequent frequencies are greater than the optimal frequency f. g The reflection parameters (i.e., the inflection point with a concave shape).

[0118] In some further embodiments, in the optimal frequency determination step, the self-reference frequency f can be determined first.b The search direction is shifted towards high frequency or low frequency. Further, the electromagnetic wave generation module 120 is controlled to adjust the frequency of the electromagnetic wave signal it generates until the reflection parameter reaches a concave inflection point.

[0119] For example, the frequency f can be obtained separately from the reference frequency. b The frequency greater than the second step size W2 and the frequency greater than the reference frequency f b For reflection parameters with frequencies less than the second step size W2, compare the magnitudes of the two reflection parameters and determine the direction corresponding to the frequency with the smaller reflection parameter as the search direction.

[0120] In some further embodiments, if the optimal frequency f g If the corresponding reflection parameter is greater than the preset second reflection threshold S2, the electromagnetic wave generating module 120 will stop working and issue a visual and / or auditory signal to indicate a fault, in order to avoid poor heating effect. The second reflection threshold S2 may be less than the first reflection threshold S1.

[0121] In some further embodiments, if the optimal frequency f g Greater than or equal to the preset minimum frequency threshold f i And less than or equal to the preset maximum frequency threshold f a According to the optimal frequency f g Determine the remaining heating time, and when the remaining heating time is 0, control the electromagnetic wave generating module 120 to stop working and emit visual and / or auditory signals to indicate that heating is complete.

[0122] In some further embodiments, if the optimal frequency f g Less than the minimum frequency threshold f i The electromagnetic wave generating module 120 is controlled to stop working and emits visual and / or auditory signals to indicate overload, so as to avoid excessive heating time.

[0123] Minimum frequency threshold f i The difference between the minimum value and the minimum value of the candidate frequency range can be 15% to 30% of the difference between the maximum and minimum values ​​of the candidate frequency range. For example, 15%, 20%, 25%, or 30%.

[0124] In some further embodiments, if the optimal frequency f g Greater than the maximum frequency threshold f a The electromagnetic wave generating module 120 is controlled to stop working and emits visual and / or auditory signals to indicate that it is unloaded, so as to avoid damaging the electromagnetic wave generating system.

[0125] The maximum value of the candidate frequency range and the maximum frequency threshold f aThe difference can be 5% to 10% of the difference between the maximum and minimum values ​​in the candidate frequency range. For example, 5%, 7%, 8%, or 10%.

[0126] Figure 4 This 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 In the text, "Y" indicates "yes"; "N" indicates "no". See also... Figure 4 The control method for the heating device 100 of the present invention may include the following detailed steps:

[0127] Step S402: Control the electromagnetic wave generating system to adjust the frequency of the electromagnetic wave it generates within a preset candidate frequency range according to the preset first step length W1, and obtain the reflection parameters corresponding to each frequency generated by the electromagnetic wave generating system.

[0128] Step S404: Determine if there is a reflection parameter less than the first reflection threshold S1. If yes, proceed to step S406; otherwise, proceed to step S408.

[0129] Step S406: Determine the reference frequency f based on the frequency corresponding to the first reflection parameter that is less than the first reflection threshold S1. b Execute step S410.

[0130] Step S408: Control the electromagnetic wave generating system to stop working and issue visual and / or auditory signals to indicate the fault.

[0131] Step S410: Within the selected frequency range, control the electromagnetic wave generating system to adjust the frequency of the generated electromagnetic waves according to the second step size W2, obtain the reflection parameters corresponding to each frequency until the reflection coefficient shows a concave inflection point, and determine the frequency corresponding to the inflection point as the optimal frequency f. g .

[0132] Step S412: Based on the optimal frequency f g Determine the remaining heating time, the first frequency difference threshold D1, and the second frequency difference threshold D2.

[0133] Step S414: If the preset frequency modulation conditions are met, control the electromagnetic wave generating system to adjust the frequency of the electromagnetic waves it generates to meet the preset matching conditions, calculate the single frequency difference between the frequency after adjustment and before adjustment, and store the single frequency difference of the most recent preset number of times.

[0134] Step S416: Calculate the cumulative frequency difference Δf of any one or more frequency adjustments within a preset number of cycles based on the stored single frequency difference, and determine whether the cumulative frequency difference Δf of any one or more frequency adjustments within the preset number of cycles is greater than the first frequency difference threshold D1. If yes, proceed to step S418; if no, proceed to step S420.

[0135] Step S418: Control the electromagnetic wave generating system to reduce the power of the electromagnetic waves it generates and extend the remaining heating time. Return to step S414.

[0136] Step S420: Determine whether the cumulative frequency difference Δf of the preset number of frequency adjustments is less than the second frequency difference threshold D2. If yes, proceed to step S422; if no, proceed to step S424.

[0137] Step S422: Control the electromagnetic wave generating system to stop working.

[0138] Step S424: Determine if the remaining heating time is equal to 0. If yes, proceed to step S422; otherwise, return to step S414.

[0139] 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 cavity for placing a workpiece and an electromagnetic wave generating system for generating electromagnetic waves within the cavity to heat the workpiece, wherein, The control method includes: Frequency matching step: If the preset frequency tuning conditions are met, the electromagnetic wave generating system is controlled to adjust the frequency of the electromagnetic waves it generates in order to meet the preset matching conditions. Power adjustment step: If the cumulative frequency difference of any one or more frequency adjustments within the preset number of times in the frequency matching step is greater than the first frequency difference threshold, the electromagnetic wave generating system is controlled to reduce the power of the electromagnetic wave it generates.

2. The control method according to claim 1, wherein, The process also includes the following steps prior to the frequency matching step: Time determination step: Determine the remaining heating time of the object to be processed; and The following steps are included after the power regulation step: Time correction step: Extend the remaining heating time.

3. The control method according to claim 2, wherein, The reduction ratio of the electromagnetic wave power in the power adjustment step is less than the extension ratio of the remaining heating time in the time correction step.

4. The control method according to claim 2, wherein, In the power regulation step, the power of the electromagnetic wave is reduced by 20% to 40%; and / or In the time correction step, the remaining heating time is extended by 35% to 55%.

5. The control method according to claim 1, further comprising: Special termination step: If the cumulative frequency difference of the preset number of frequency adjustments in the frequency matching step is less than the second frequency difference threshold, the electromagnetic wave generating system is controlled to immediately stop working or continue working for a preset time before stopping working; wherein, The second frequency difference threshold is less than the first frequency difference threshold.

6. The control method according to claim 5, wherein, The process also includes the following steps prior to the frequency matching step: Initial frequency determination step: Determine the initial frequency for heating the object to be processed based on the reflection parameters of the electromagnetic wave generating system; Threshold determination step: Determine the first frequency difference threshold and the second frequency difference threshold based on the initial frequency; wherein, The first frequency difference threshold and the second frequency difference threshold are positively correlated with the initial frequency.

7. The control method according to claim 6, wherein, The initial frequency determination step further includes: Reference frequency determination steps: Control the electromagnetic wave generating system to adjust the frequency of the electromagnetic wave it generates within a preset candidate frequency range according to a preset first step length, obtain the reflection parameters corresponding to each frequency generated by the electromagnetic wave generating system, and determine the reference frequency based on the reflection parameters. The optimal frequency determination step involves controlling the electromagnetic wave generating system to adjust the frequency of the generated electromagnetic waves within a selected frequency range according to a preset second step size, obtaining the reflection parameters corresponding to each frequency generated by the electromagnetic wave generating system, and determining the optimal frequency as the initial frequency based on the reflection parameters; wherein, The selected frequency range is based on the reference frequency and is within a range of frequencies with the absolute value of the first step length as the radius; and The absolute value of the second step length is less than the absolute value of the first step length.

8. The control method according to claim 1, wherein, In the frequency matching step, the single frequency difference before and after frequency adjustment is calculated, and the single frequency difference of the most recent preset number of times is stored; and The cumulative frequency difference is the sum of the single frequency differences for the corresponding number of times.

9. The control method according to claim 1, wherein, If, during the frequency matching step, each frequency generated by the electromagnetic wave generating system does not meet the preset matching condition, the electromagnetic wave generating system is controlled to generate electromagnetic waves with frequencies equal to the minimum value of the preset candidate frequency range.

10. A heating device, comprising: A cavity, used to hold the object to be processed; An electromagnetic wave generating system is used to generate electromagnetic waves within the cavity to heat the object to be processed. as well as A controller configured to perform the control method as described in any one of claims 1-9.

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