阅读说明：本技术 用于加热装置的解冻方法及加热装置 (Thawing method for heating device and heating device ) 是由 韩志强 王铭 李鹏 王海娟 李春阳 姬立胜 于 2020-04-22 设计创作，主要内容包括：本发明提供了一种用于加热装置的解冻方法及加热装置。加热装置包括用于放置待处理物的腔体电容、以及产生用于加热待处理物的电磁波信号的电磁波发生模块,其中,解冻方法包括：接收用户输入的解冻指令；获取体现待处理物重量的特征参数、电磁波信号的功率值、以及待处理物的介电系数的变化速率；根据特征参数、功率值以及变化速率确定待处理物的解冻进度。本发明根据电磁波信号的功率、待处理物的重量、以及待处理物的介电系数的变化速率确定解冻进度,相比于根据感测到的待处理物的温度来判断待处理物的解冻进度,受感测器件本身的精度影响较小,判断更加准确,有利于用户对解冻后的待处理物作进一步的处理。(The invention provides a thawing method for a heating device and the heating device. The heating device comprises a cavity capacitor for placing the object to be treated and an electromagnetic wave generating module for generating an electromagnetic wave signal for heating the object to be treated, wherein the unfreezing method comprises the following steps: receiving a thawing instruction input by a user; acquiring characteristic parameters reflecting the weight of the object to be processed, the power value of the electromagnetic wave signal and the change rate of the dielectric coefficient of the object to be processed; and determining the thawing progress of the object to be treated according to the characteristic parameters, the power value and the change rate. Compared with the method for judging the thawing progress of the object to be treated according to the sensed temperature of the object to be treated, the method for judging the thawing progress of the object to be treated has the advantages that the thawing progress is determined according to the power of the electromagnetic wave signal, the weight of the object to be treated and the change rate of the dielectric coefficient of the object to be treated, the influence of the self precision of the sensing device is small, the judgment is more accurate, and the method is favorable for further processing the thawed object to be treated by a user.)

1. A thawing method for a heating apparatus including a cavity capacitor for placing an object to be treated and an electromagnetic wave generating module generating an electromagnetic wave signal for heating the object to be treated, wherein the thawing method comprises:

receiving a thawing instruction input by a user;

acquiring characteristic parameters reflecting the weight of the object to be processed, the power value of the electromagnetic wave signal and the change rate of the dielectric coefficient of the object to be processed;

and determining the thawing progress of the object to be treated according to the characteristic parameters, the power value and the change rate.

2. The thawing method of claim 1, wherein said step of determining the thawing progress of the object to be treated according to said characteristic parameters, power values and rate of change comprises:

determining a change threshold of the dielectric coefficient of the object to be treated according to the characteristic parameter and the power value;

and when the change rate is smaller than the change threshold value, controlling the electromagnetic wave generation module to stop working.

3. The thawing method according to claim 2, wherein said step of determining a threshold value of variation of permittivity of the object to be treated from said characteristic parameter, said power value comprises:

matching a corresponding change threshold according to the characteristic parameters and the power value according to a preset comparison relation; wherein

In the case of the same power value, the variation threshold is inversely proportional to the weight embodied by the characteristic parameter; and/or

In the case of the same weight represented by the characteristic parameter, the variation threshold is proportional to the power value.

4. The thawing method according to claim 1, wherein said step of obtaining a characteristic parameter representative of the weight of the object to be treated comprises:

and acquiring the capacitance value of the cavity capacitor, wherein the characteristic parameter is the capacitance value.

5. The thawing method according to claim 1, wherein said heating means further comprises a matching module for adjusting a load impedance of said electromagnetic wave generation module by adjusting its own impedance, wherein said step of obtaining a characteristic parameter representing a weight of the object to be treated comprises:

controlling the electromagnetic wave generation module to generate an electromagnetic wave signal with preset initial power;

adjusting the impedance of the matching module and determining the impedance value of the matching module that achieves the optimal load matching of the electromagnetic wave generation module.

6. The thawing method of claim 5, said matching module comprising a plurality of matching branches that can be independently switched on and off, wherein said adjusting impedance of said matching module and determining an impedance value of said matching module that achieves optimal load matching of said electromagnetic wave generation module comprises:

traversing the on-off combinations of the plurality of matching branches, and acquiring a matching degree parameter corresponding to each on-off combination and reflecting the load matching degree of the electromagnetic wave generation module;

comparing the matching degree parameters of the on-off combination of the plurality of matching branches;

and determining the on-off combination for realizing the optimal load matching according to the comparison result.

7. The thawing method according to claim 6, wherein the step of traversing the on-off combinations of the plurality of matching branches and obtaining the matching degree parameter corresponding to each on-off combination and reflecting the load matching degree of the electromagnetic wave generation module comprises:

acquiring a preset number set, wherein the number set comprises a combined number of on-off combination of the plurality of matching branches, and the combined number corresponds to the impedance value;

and determining the branch serial numbers of the matched branches corresponding to each combination serial number one by one according to the serial number set, and controlling the on-off of the corresponding matched branches according to the branch serial numbers.

8. The thawing method according to claim 7,

the characteristic parameter is an impedance value of the matching module for optimal load matching or the combination number.

9. The thawing method according to claim 1, wherein said step of obtaining a characteristic parameter representative of the weight of the object to be treated comprises:

controlling the electromagnetic wave generation module to generate an electromagnetic wave signal with preset initial power;

and adjusting the frequency of the electromagnetic wave signal in the alternative frequency interval, and determining the frequency value of the electromagnetic wave signal for realizing the optimal frequency matching of the cavity capacitor, wherein the characteristic parameter is the frequency value of the electromagnetic wave signal for realizing the optimal frequency matching.

10. A heating device, comprising:

the cavity capacitor is used for placing an object to be processed;

the electromagnetic wave generating module is configured to generate an electromagnetic wave signal and is used for heating the object to be processed in the cavity capacitor; and

a controller configured to perform the thawing method of any of claims 1-9.

Technical Field

The invention relates to the field of food processing, in particular to a thawing method for an electromagnetic wave heating device and the heating device.

Background

During the freezing process, the quality of the food is maintained, however, the frozen food needs to be thawed before processing or consumption. In order to facilitate the user to thaw the food, the food is generally thawed by the electromagnetic wave heating device.

The electromagnetic wave heating device is used for unfreezing the food, so that the speed is high, the efficiency is high, and the loss of nutritional ingredients of the food is low. However, in the prior art, the end of thawing is generally determined by setting time or temperature by a user, which not only makes an excessive request to the user and easily causes the food after thawing to be too cold or too hot, but also causes problems of uneven thawing and local overheating due to difference in penetration and absorption of water and ice by microwaves, uneven distribution of substances in the food, and large amount of energy absorbed by a melted region.

Disclosure of Invention

It is an object of the first aspect of the present invention to overcome at least one of the technical drawbacks of the prior art and to provide a thawing method for a heating device.

A further object of the first aspect of the present invention is to obtain the weight of the object to be treated more accurately.

It is a further object of the first aspect of the invention to improve the efficiency of obtaining characteristic parameters.

It is an object of the second aspect of the invention to provide a heating device.

According to a first aspect of the present invention, there is provided a thawing method for a heating apparatus including a cavity capacitor for placing an object to be treated and an electromagnetic wave generating module generating an electromagnetic wave signal for heating the object to be treated, wherein the thawing method includes:

receiving a thawing instruction input by a user;

acquiring characteristic parameters reflecting the weight of the object to be processed, the power value of the electromagnetic wave signal and the change rate of the dielectric coefficient of the object to be processed;

and determining the thawing progress of the object to be treated according to the characteristic parameters, the power value and the change rate.

Optionally, the step of determining the thawing progress of the object to be treated according to the characteristic parameter, the power value and the change rate comprises:

determining a change threshold of the dielectric coefficient of the object to be treated according to the characteristic parameter and the power value;

and when the change rate is smaller than the change threshold value, controlling the electromagnetic wave generation module to stop working.

Optionally, the step of determining the threshold value of the change of the dielectric coefficient of the object to be treated according to the characteristic parameter and the power value comprises:

matching a corresponding change threshold according to the characteristic parameters and the power value according to a preset comparison relation; wherein

In the case of the same power value, the variation threshold is inversely proportional to the weight embodied by the characteristic parameter; and/or

In the case of the same weight represented by the characteristic parameter, the variation threshold is proportional to the power value.

Optionally, the step of obtaining the characteristic parameter representing the weight of the object to be treated includes:

and acquiring the capacitance value of the cavity capacitor, wherein the characteristic parameter is the capacitance value.

Optionally, the heating apparatus further includes a matching module for adjusting a load impedance of the electromagnetic wave generating module by adjusting its own impedance, wherein the step of obtaining the characteristic parameter representing the weight of the object to be treated includes:

controlling the electromagnetic wave generation module to generate an electromagnetic wave signal with preset initial power;

adjusting the impedance of the matching module and determining the impedance value of the matching module that achieves the optimal load matching of the electromagnetic wave generation module.

Optionally, the matching module includes a plurality of matching branches that can be independently switched on and off, wherein the adjusting the impedance of the matching module and determining the impedance value of the matching module that achieves the optimal load matching of the electromagnetic wave generation module includes:

traversing the on-off combinations of the plurality of matching branches, and acquiring a matching degree parameter corresponding to each on-off combination and reflecting the load matching degree of the electromagnetic wave generation module;

comparing the matching degree parameters of the on-off combination of the plurality of matching branches;

and determining the on-off combination for realizing the optimal load matching according to the comparison result.

Optionally, the step of traversing the on-off combinations of the plurality of matching branches and obtaining a matching degree parameter corresponding to each on-off combination and reflecting the load matching degree of the electromagnetic wave generation module includes:

acquiring a preset number set, wherein the number set comprises a combined number of on-off combination of the plurality of matching branches, and the combined number corresponds to the impedance value;

and determining the branch serial numbers of the matched branches corresponding to each combination serial number one by one according to the serial number set, and controlling the on-off of the corresponding matched branches according to the branch serial numbers.

Optionally, the characteristic parameter is an impedance value of the matching module for optimal load matching, or the combination number.

Optionally, the step of obtaining the characteristic parameter representing the weight of the object to be treated includes:

controlling the electromagnetic wave generation module to generate an electromagnetic wave signal with preset initial power;

and adjusting the frequency of the electromagnetic wave signal in the alternative frequency interval, and determining the frequency value of the electromagnetic wave signal for realizing the optimal frequency matching of the cavity capacitor, wherein the characteristic parameter is the frequency value of the electromagnetic wave signal for realizing the optimal frequency matching.

According to a second aspect of the present invention, there is provided a heating apparatus comprising:

the cavity capacitor is used for placing an object to be processed;

the electromagnetic wave generating module is configured to generate an electromagnetic wave signal and is used for heating the object to be processed in the cavity capacitor; and

a controller configured to perform any of the thawing methods described above.

Compared with the method for judging the thawing progress of the object to be treated according to the sensed temperature of the object to be treated, the method for judging the thawing progress of the object to be treated has the advantages that the thawing progress is determined according to the power of the electromagnetic wave signal, the weight of the object to be treated and the change rate of the dielectric coefficient of the object to be treated, the influence of the self precision of the sensing device is small, the judgment is more accurate, and the method is favorable for further processing the thawed object to be treated by a user.

Furthermore, the invention compares the change rate of the dielectric coefficient of the object to be treated with the change threshold value determined by the power of the electromagnetic wave signal and the weight of the object to be treated to determine whether the thawing is finished, can effectively prevent the object to be treated from being excessively thawed, is particularly suitable for the object to be treated with the expected thawing temperature of-4 to-1 ℃, can ensure that the thawed meat food material has no blood water and is convenient to cut, and the vegetable food material has no water and has less nutrition loss.

Furthermore, the weight of the object to be processed is reflected by parameters (capacitance, impedance value of a matching module for realizing optimal load matching, frequency value of an electromagnetic wave signal for realizing optimal frequency matching and the like) related to the capacitance of the cavity capacitor, and a user does not need to manually input the weight of the object to be processed according to experience or measurement or add a weighing sensor in the cavity capacitor, so that the cost is saved, and the fault-tolerant rate is improved.

Furthermore, each on-off combination and each matching branch of the matching module are respectively numbered, so that the matching branch corresponding to each on-off combination can be quickly matched for on-off in the process of determining the impedance value of the matching module for realizing the optimal load matching of the electromagnetic wave generation module, the time for determining the characteristic parameters of the object to be processed is shortened, and the user experience is greatly improved. Particularly, according to the numbering method disclosed by the invention, the corresponding change threshold value can be matched directly through the combination number, the control flow is simplified, and the time for determining the characteristic parameters of the object to be processed is further shortened.

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 thereof, taken in conjunction with the accompanying drawings.

Drawings

Some specific embodiments of the invention will be described in detail hereinafter, by way of illustration and not limitation, with reference to the accompanying drawings. The same reference numbers in the drawings identify the same or similar elements or components. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. In the drawings:

FIG. 1 is a schematic block diagram of a heating apparatus according to one embodiment of the present invention;

FIG. 2 is a schematic block diagram of the controller of FIG. 1;

FIG. 3 is a schematic circuit diagram of a matching module according to one embodiment of the present invention;

FIG. 4 is a schematic flow diagram of a thawing method for a heating apparatus according to an embodiment of the present invention;

FIG. 5 is a detailed flow diagram of a thawing method for a heating apparatus according to an embodiment of the present invention;

FIG. 6 is a schematic flow chart of determining a threshold for change in the dielectric constant of an object to be treated according to another embodiment of the present invention.

Detailed Description

Fig. 1 is a schematic structural view of a heating apparatus 100 according to an embodiment of the present invention. Referring to fig. 1, the heating apparatus 100 may include a cavity capacitor 110, an electromagnetic wave generation module 120, and a controller 140.

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

The electromagnetic wave generating module 120 may be configured to generate an electromagnetic wave signal and electrically connect to the radiation plate of the cavity capacitor 110 to generate an electromagnetic wave in the cavity capacitor 110, so as to heat the object 150 to be processed in the cavity capacitor 110.

Fig. 2 is a schematic block diagram of the controller 140 of fig. 1. Referring to fig. 2, the controller 140 may include a processing unit 141 and a storage unit 142. Wherein the storage unit 142 stores a computer program 143, the computer program 143 being executed by the processing unit 141 for implementing the control method of an embodiment of the present invention.

In particular, the processing unit 141 may be configured to obtain a characteristic parameter representing the weight of the object 150 to be treated, a power value (i.e., heating power) of an electromagnetic wave signal for heating the object 150 to be treated, and a change rate of the dielectric coefficient of the object 150 to be treated after receiving a thawing instruction input by a user, and further determine the thawing progress of the object 150 to be treated according to the characteristic parameter, the heating power, and the change rate of the dielectric coefficient of the object 150 to be treated.

The heating device 100 of the present invention determines the thawing progress according to the power of the electromagnetic wave signal for heating the object to be treated 150, the weight of the object to be treated 150, and the change rate of the dielectric coefficient of the object to be treated 150, and compared with the method for determining the thawing progress of the object to be treated 150 according to the sensed temperature of the object to be treated 150, the method is less affected by the accuracy of the sensing device itself, and is more accurate in determination, thereby facilitating the user to further process the thawed object to be treated 150.

In some embodiments, the processing unit 141 may be further configured to determine a threshold value of the change of the dielectric coefficient of the object 150 to be processed according to the characteristic parameter and the heating power, for determining whether the thawing is completed.

When the rate of change of the dielectric constant of the object 150 is less than the change threshold, the processing unit 141 may control the electromagnetic wave generating module 120 to stop operating, i.e., stop heating the object 150, so as to prevent the object 150 from being excessively thawed.

The processing unit 141 may be configured to match the corresponding variation threshold according to the characteristic parameter and the heating power according to a preset comparison relationship. Wherein, under the condition of the same power value, the change threshold value and the weight embodied by the characteristic parameter can be approximately in inverse proportion. Under the condition that the weight embodied by the characteristic parameters is the same, the change threshold value and the power value can be approximately in direct proportion so as to be suitable for food materials of different types and weights and avoid over-thawing or incomplete thawing. The comparison relationship can be a formula, a comparison table, and the like.

In some further embodiments, the processing unit 141 may be configured to determine the power value of the electromagnetic wave signal for heating the object 150 to be processed according to the food material group of the object 150 to reduce the heating unevenness and local overheating phenomenon caused by different contents of the internal substances of different food materials.

The food material group can be input by a user, or can be judged through image recognition, spectrum recognition and the like. Each food material group can comprise at least one food material variety so as to improve the fault tolerance rate and reduce the requirement on users.

The change threshold value can be determined by performing heating experiments with different heating powers on different types and weights of the to-be-treated substance 150 and detecting the change rate of the dielectric coefficient of the to-be-treated substance 150 at-4 to-1 ℃ so as to further improve the accuracy of judging whether thawing is completed, so that the thawed meat food material has no blood and is convenient to cut, and the vegetable food material has no water and has less nutrition loss.

In some embodiments, the characteristic parameter reflecting the weight of the object 150 to be processed may be the capacitance value of the cavity capacitor 110, and the user does not need to manually input the weight of the object 150 to be processed according to experience or measurement, or a weighing sensor is added in the cavity capacitor 110, so that not only is the cost saved, but also the fault tolerance rate is improved.

In some further embodiments, the heating device 100 further comprises a matching module 130. The matching module 130 may be connected in series between the electromagnetic wave generating module 120 and the cavity capacitor 110 or connected in parallel to 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, so as to implement load matching and improve heating efficiency.

The processing unit 141 may be configured to control the electromagnetic wave generating module 120 to generate an electromagnetic wave signal with a preset initial power, adjust the impedance of the matching module 130 to perform load matching, determine the impedance value of the matching module 130 that realizes the optimal load matching of the electromagnetic wave generating module 120, and further determine the capacitance of the cavity capacitor 110 according to the impedance value of the matching module 130 that realizes the optimal load matching or directly use the impedance value of the matching module 130 that realizes the optimal load matching as a characteristic parameter.

The matching module 130 may include a plurality of matching branches that may be independently switched on and off. The processing unit 141 may be further configured to traverse the on-off combinations of the multiple matching branches, obtain a matching degree parameter corresponding to each on-off combination and reflecting the load matching degree of the electromagnetic wave generation module 120, compare the matching degree parameters of the on-off combinations of the multiple matching branches, and determine, according to a comparison result, an on-off combination for achieving optimal load matching and an impedance value corresponding to the on-off combination.

Specifically, the storage unit 142 may store a preset number set, where the number set may include a combination number of on-off combinations of the plurality of matching branches, and the combination number corresponds to the impedance value of the matching module 130. The processing unit 141 may be further configured to obtain a preset number set after the heating instruction is obtained, determine the branch numbers of the matching branches corresponding to each combination number one by one according to the number set, and control the on/off of the corresponding matching branches according to the branch numbers, so as to implement traversing on the on/off combination of the multiple matching branches.

According to the heating device 100, each on-off combination and each matching branch of the matching module 130 are numbered respectively, so that the matching branch corresponding to each on-off combination can be matched quickly to be on or off in the process of determining the impedance value of the matching module 130 for realizing the optimal load matching of the electromagnetic wave generation module 120, the time required for determining the capacitance of the cavity capacitor 110 is shortened, and the user experience is greatly improved.

In this embodiment, the characteristic parameter may be an impedance value of the matching module 130 with the optimal load matching, or a combination number, so as to simplify the control flow and further shorten the time required for determining the characteristic parameter of the object 150 to be processed.

The branch numbers of the matching branches can be sequentially 0 to n-1 power of a constant A, and the combination number can be the sum of the branch numbers of the conducting matching branches in the on-off combination, so that only one conducting matching branch can be accurately determined through the branch numbers. Where the constant a may be 2, 3, or 4, etc., and n is the number of matching branches. In the invention, the constant A can be 2, so that the storage space occupied by the number is reduced, and the matching efficiency is improved.

Fig. 3 is a schematic circuit diagram of the matching module 130 according to one embodiment of the present invention. Referring to fig. 3, in some further embodiments, the matching module 130 may include a first matching unit 131 connected in series between the electromagnetic wave generating module 120 and the cavity capacitance 110, and a second matching unit 132 having one end electrically connected between the first matching unit 131 and the cavity capacitance 110 and the other end grounded. The first matching unit 131 and the second matching unit 132 may respectively include a plurality of matching branches connected in parallel, and each matching branch includes a fixed-value capacitor and a switch, so that the reliability and the adjustment range of the matching module 130 are improved while the circuit is simple, and the acquired impedance value of the matching module 130 for realizing the optimal load matching is further improved.

The capacitance values of the constant capacitors of the second matching units 132 of the first matching unit 131 and the second matching unit 132 may be different, and the capacitance value of the minimum constant capacitor of the second matching unit 132 may be greater than the capacitance value of the maximum constant capacitor of the first matching unit 131. The serial numbers of the multiple branch circuits can be sequentially increased from small to large according to the capacitance values of the corresponding matching branch circuits.

Referring to fig. 3, the capacitance C of the first matching unit 131₁、C₂、…、C_aThe capacitance value of the second matching unit 132 is increased in turn, the capacitance C of the second matching unit 132_x1、C_x2、…、C_xb(where a + b ═ n) in this order, and the capacitance C increases_x1Is greater than the capacitance C_aThe capacitance value of (2). In the embodiment where the constant a is 2,C₁、C₂、…、C_a、C_x1、C_x2、…、C_xbthe corresponding matching branches can be numbered as 2 in sequence⁰、2¹、…、2^a-1、2^a、2^a+1、…、2^n-1。

According to the formula f 1/(2 pi · sqrt (L · C) for calculating the resonant frequency, when the capacitance C of the cavity capacitor 110 changes due to the different objects 150 to be processed being placed in the same heating apparatus 100 (the inductance L remains constant), the resonant frequency f suitable for the cavity capacitor 110 also changes.

The processing unit 141 may be configured to, after acquiring the heating instruction, control the electromagnetic wave generation module 120 to generate an electromagnetic wave signal with a preset initial power, adjust the frequency of the electromagnetic wave signal generated by the electromagnetic wave generation module 120 in the alternative frequency interval, determine the frequency value of the electromagnetic wave signal that achieves the optimal frequency matching of the cavity capacitor 110, and further determine the capacitance of the cavity capacitor 110 according to the frequency value that achieves the optimal frequency matching or directly use the frequency value that achieves the optimal frequency matching as the characteristic parameter.

The minimum value of the alternative frequency interval can be 32-38 MHz, and the maximum value can be 42-48 MHz, so that the penetrability of electromagnetic waves is improved, and uniform heating is realized. For example, the candidate frequency ranges are 32 to 48MHz, 35 to 45MHz, 38 to 42MHz, etc.

The processing unit 141 may be configured to adjust the frequency of the electromagnetic wave signal within the candidate frequency interval in a dichotomy manner, gradually reduce the frequency approximation interval in which the optimal frequency matching is achieved to the minimum approximation interval, and further determine the frequency value of the electromagnetic wave signal in which the optimal frequency matching is achieved.

Specifically, the processing unit 141 may be configured to adjust the frequency of the electromagnetic wave signal to be the minimum value, the intermediate value, and the maximum value of the frequency approximation interval, respectively obtain the matching degree parameters corresponding to each frequency and reflecting the frequency matching degree of the cavity capacitor 110 for comparison, re-determine the frequency approximation interval according to the comparison result, and so forth until the frequency approximation interval is the minimum approximation interval, adjust the frequency of the electromagnetic wave signal to be the minimum value, the intermediate value, and the maximum value of the minimum approximation interval, respectively obtain the matching degree parameters corresponding to each frequency and reflecting the frequency matching degree of the cavity capacitor 110 for comparison, and determine the optimal frequency value according to the comparison result. Wherein, the initial frequency approximation interval may be the aforementioned alternative frequency interval.

The heating device 100 of the invention determines the frequency value for realizing the optimal frequency matching in the alternative frequency interval by the dichotomy, can quickly reduce the range of the interval where the optimal frequency value is located, further quickly determines the optimal frequency value, shortens the time required for determining the capacitance of the cavity capacitor 110, and greatly improves the user experience.

It should be noted that, in the present invention, the minimum approximation interval is not an interval of a specific frequency range, but a minimum range of the frequency approximation interval, that is, the precision of the optimal frequency value. In some embodiments, the minimum approximation interval may be any value of 0.2-20 KHz, such as 0.2KHz, 1KHz, 5KHz, 10KHz, or 20 KHz. The time interval between two adjacent adjusting frequencies of the electromagnetic wave signal may be 10-20 ms, such as 10ms, 15ms, or 20 ms.

In some embodiments, the variable frequency source may be a voltage controlled oscillator, the input voltage of which corresponds to the output frequency. The processing unit 141 may be configured to determine the capacitance of the cavity capacitor 110 from the input voltage of the voltage controlled oscillator or directly use the input voltage as a characteristic parameter.

In the present invention, the optimal load matching of the electromagnetic wave generation module 120 and the optimal frequency matching of the cavity capacitor 110 mean that the proportion of the output power distributed to the cavity capacitor 110 by the electromagnetic wave generation module 120 is the largest under the same heating apparatus 100.

In the invention, the preset initial power can be 10-20W, such as 10W, 15W or 20W, so that the impedance value for realizing the optimal load matching or the frequency value for realizing the optimal frequency matching with high accuracy can be obtained while energy is saved.

In some embodiments, the heating apparatus 100 may further include a bidirectional coupler connected in series between the cavity capacitor 110 and the electromagnetic wave generating module 120, for monitoring the forward power signal output by the electromagnetic wave generating module 120 and the reverse power signal returned to the electromagnetic wave generating module 120 in real time.

The processing unit 141 may be further configured to obtain the forward power signal output by the electromagnetic wave generation module 120 and the reverse power signal returned to the electromagnetic wave generation module 120 after adjusting the impedance value of the matching module 130 or after adjusting the frequency of the electromagnetic wave signal each time, and calculate the matching degree parameter according to the forward power signal and the reverse power signal.

The matching degree parameter may be a return loss S11, which may be calculated according to a formula S11 — 20log (reverse power/forward power), in this embodiment, the smaller the value of the return loss S11, the higher the load matching degree of the electromagnetic wave generation module 120 or the frequency matching degree of the cavity capacitor 110 is reflected, and the impedance value or the frequency value corresponding to the minimum return loss S11 is the impedance value for achieving the optimal load matching or the frequency value for achieving the optimal frequency matching.

The matching degree parameter may also be an electromagnetic wave absorption rate, which may be calculated according to a formula (1-reverse power/forward power), in this embodiment, the larger the value of the electromagnetic wave absorption rate is, the higher the load matching degree of the electromagnetic wave generation module 120 or the frequency matching degree of the cavity capacitor 110 is reflected, and the impedance value or the frequency value corresponding to the maximum electromagnetic wave absorption rate is the impedance value for achieving the optimal load matching or the frequency value for achieving the optimal frequency matching.

The matching degree parameter may also be other parameters that can represent the proportion of the output power distributed to the cavity capacitor 110 by the electromagnetic wave generation module 120.

In still further embodiments, the capacitance of the cavity capacitor 110 may be measured directly by a capacitance measuring instrument.

Fig. 4 is a schematic flow diagram of a thawing method for the heating apparatus 100 according to an embodiment of the present invention. Referring to fig. 4, the thawing method for the heating apparatus 100 performed by the controller 140 of any of the above embodiments of the present invention may include the steps of:

step S402: and receiving a defrosting instruction input by a user.

Step S404: characteristic parameters representing the weight of the object 150 to be treated, the power value of the electromagnetic wave signal for heating the object 150 to be treated, and the rate of change of the dielectric constant of the object 150 to be treated are obtained.

Step S406: and determining the thawing progress of the object 150 to be treated according to the characteristic parameters, the power value and the change rate.

Compared with the method for judging the thawing progress of the object to be treated 150 according to the sensed temperature of the object to be treated 150, the thawing method of the invention has the advantages that the thawing progress is determined according to the power of the electromagnetic wave signal, the weight of the object to be treated 150 and the change rate of the dielectric coefficient of the object to be treated 150, the thawing progress is less influenced by the accuracy of the sensing device, the judgment is more accurate, and the method is beneficial for a user to further process the thawed object to be treated 150.

In some embodiments, step S406 may include the steps of:

determining a variation threshold of the dielectric coefficient of the object 150 to be processed according to the characteristic parameter and the power value of the electromagnetic wave signal for heating the object 150 to be processed;

the change rate of the dielectric coefficient of the object 150 to be processed is detected in real time, and when the change rate is smaller than the change threshold, the electromagnetic wave generating module 120 is controlled to stop working.

The change threshold value can be determined by matching the characteristic parameters and the heating power according to a preset comparison relation, and is inversely proportional to the weight reflected by the characteristic parameters under the condition that the heating power is the same. The variation threshold is proportional to the heating power, with the same weight as the characteristic parameter.

The characteristic parameter reflecting the weight of the object 150 to be processed may be the capacitance of the cavity capacitor 110 after the object 150 to be processed is placed in the cavity, the impedance value of the matching module 130 for realizing the optimal load matching, or the frequency value of the electromagnetic wave signal for realizing the optimal frequency matching, etc., and the user does not need to manually input the weight of the object 150 to be processed according to experience or measurement, or a weighing sensor is added in the cavity capacitor 110, which not only saves the cost, but also improves the fault tolerance.

In some embodiments, obtaining the characteristic parameter representing the weight of the object 150 to be processed may include the steps of:

controlling the electromagnetic wave generation module 120 to generate an electromagnetic wave signal with a preset initial power;

adjusting the impedance of the matching module 130, determining the impedance value of the matching module 130 that achieves the optimal load matching of the electromagnetic wave generation module 120, and further determining the capacitance of the cavity capacitor 110 according to the impedance value of the matching module 130 that achieves the optimal load matching or directly using the impedance value of the matching module 130 that achieves the optimal load matching as a characteristic parameter.

Specifically, adjusting the impedance of the matching module 130 and determining the impedance value of the matching module 130 that realizes the optimal load matching of the electromagnetic wave generation module 120 may specifically be traversing on-off combinations of multiple matching branches, and obtaining a matching degree parameter that reflects the load matching degree of the electromagnetic wave generation module 120 and corresponds to each on-off combination; comparing the matching degree parameters of the on-off combination of the plurality of matching branches; and determining the on-off combination for realizing the optimal load matching according to the comparison result.

Fig. 5 is a detailed flowchart of a thawing method for the heating apparatus 100 according to an embodiment of the present invention (in the drawings for description of the present invention, "Y" means "yes;" N "means" no "). Referring to fig. 5, the thawing method for the heating apparatus 100 according to an embodiment of the present invention may include the following detailed steps:

step S502: and acquiring a thawing instruction input by a user.

Step S504: the food material group of the object to be processed 150 is obtained. In this step, the food material group may be input by the user, or determined by image recognition, spectrum recognition, or the like. Each food material group can comprise at least one food material variety so as to improve the fault tolerance rate and reduce the requirement on users.

Step S506: the heating power of the electromagnetic wave signal for heating the object 150 to be processed is determined according to the food material groups, so as to reduce the phenomena of uneven heating and local overheating caused by different contents of the substances in different food materials.

Step S508: the electromagnetic wave generation module 120 is controlled to generate an electromagnetic wave signal with a preset initial power.

Step S510: a pre-configured number set is obtained.

Step S512: the branch number of the matching branch corresponding to each combination number is determined one by one according to the number set, the on-off of the corresponding matching branch is controlled according to the branch number, after the matching branch corresponding to each on-off combination is turned on and off, a forward power signal output by the electromagnetic generation module and a reverse power signal returned to the electromagnetic wave generation module 120 are obtained, a matching degree parameter is calculated according to the forward power signal and the reverse power signal, the matching branch corresponding to each on-off combination is rapidly matched to be turned on and off, and therefore the time for determining the capacitance of the cavity capacitor 110 is shortened.

Step S514: and comparing the matching degree parameters of the on-off combination of the plurality of matching branches.

Step S516: and determining the on-off combination for realizing the optimal load matching according to the comparison result.

Step S518: according to the combination number of the on-off combination for realizing the optimal load matching and the heating power, the change threshold of the dielectric coefficient of the object to be processed 150 is matched according to the preset contrast relation, so that the control flow is simplified, and the time for determining the characteristic parameters of the object to be processed 150 is further shortened.

Step S520: the electromagnetic wave generation module 120 is controlled to generate an electromagnetic wave signal with heating power.

Step S522: the rate of change of the dielectric constant of the object to be processed 150 is obtained.

Step S524: it is determined whether the rate of change of the dielectric constant of the object 150 to be processed is less than a change threshold. If yes, go to step S526; if not, the process returns to step S522.

Step S526: the electromagnetic wave generation module 120 is controlled to stop operating. Returning to step S502, the next thawing cycle is started.

In other embodiments, the difference from the previous embodiment is that the obtaining of the characteristic parameter representing the weight of the object 150 to be processed may include the following steps:

controlling the electromagnetic wave generation module 120 to generate an electromagnetic wave signal with a preset initial power;

adjusting the frequency of the electromagnetic wave signal in the alternative frequency interval, determining the frequency value of the electromagnetic wave signal for realizing the optimal frequency matching of the cavity capacitor 110, and further determining the capacitance of the cavity capacitor 110 according to the frequency value for realizing the optimal frequency matching or directly taking the frequency value for realizing the optimal frequency matching as the characteristic parameter.

Fig. 6 is a schematic flowchart of determining a threshold value of variation of the dielectric constant of the object 150 to be processed according to another embodiment of the present invention. Referring to fig. 6, determining a threshold value of a change in the dielectric constant of the object 150 to be processed according to another embodiment of the present invention may include the steps of:

step S602: and acquiring an initial frequency approximation interval. Wherein, the initial frequency approximation interval may be the aforementioned alternative frequency interval.

Step S604: and adjusting the frequency of the electromagnetic wave signal to be the minimum value, the middle value and the maximum value of the frequency approximation interval, and acquiring the matching degree parameter corresponding to each frequency and reflecting the frequency matching degree of the cavity capacitor 110.

Step S606: and comparing the matching degree parameters of the frequencies.

Step S608: and judging whether the frequency approximation interval is the minimum approximation interval or not. If yes, go to step S610; if not, go to step S612.

Step S610: and determining the frequency value of the electromagnetic wave signal for realizing the optimal frequency matching according to the comparison result, and matching the change threshold value of the dielectric coefficient of the object to be processed 150 according to the frequency value and the heating power according to a preset comparison relation.

Step S612: and re-determining the frequency approximation interval according to the comparison result so as to gradually reduce the frequency approximation interval for realizing the optimal frequency matching to the minimum approximation interval, quickly reduce the range of the interval in which the optimal frequency value is positioned, and further quickly determine the optimal frequency value. The process returns to step S604.

Thus, it should be appreciated by those skilled in the art that while a number of exemplary embodiments of the invention have been illustrated and described in detail herein, many other variations or modifications consistent with the principles of the invention may be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Accordingly, the scope of the invention should be understood and interpreted to cover all such other variations or modifications.