Microwave heating equipment, control method thereof, power supply circuit and computer storage medium
By designing control methods and power supply circuits in microwave heating equipment, and using the combined structure of switch tubes and one-way conducting tubes, the heating power is accurately adjusted, solving the problem that existing equipment cannot heat less than 500W, satisfying users low power requirements and improved regulation accuracy.
Patent Information
- Application Number
- CN202411518035.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-28
- Publication Date
- 2025-01-03
AI Technical Summary
Existing microwave heating equipment cannot achieve low power heating below 500W, and cannot meet users' needs for low power heating.
A control method and power supply circuit of microwave heating equipment are designed. Through the combination of rectifier circuit, resonant circuit and inverter circuit, the parallel and series structure of the switch tube and the one-way conductor tube are used to combine pulse width modulation and driving frequency adjustment. Accurate adjustment of heating power, and the on-time can be adjusted within each AC signal cycle to achieve the target heating power.
The two-stage power adjustment of microwave heating equipment is realized, which can meet the user's low-power heating needs, improve the adjustment accuracy of heating power, and avoid the problems of excessive power adjustment amplitude and reduced device reliability caused by single factor adjustment.
Smart Images
Figure CN119255424A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of household appliances, and in particular to a control method for a microwave heating device, a power supply circuit, a microwave heating device and a computer storage medium. Background Art
[0002] Microwave heating equipment is a heating equipment that can achieve rapid heating, which is convenient and quick. However, existing microwave heating equipment, such as microwave ovens, etc., usually use high-power heating to achieve the purpose of rapid heating, which cannot meet the user's demand for low-power heating, such as less than 500W. Summary of the invention
[0003] The present application provides a control method for a microwave heating device, a power supply circuit, a microwave heating device and a computer storage medium to solve the technical problem that the existing microwave heating device cannot perform low-power heating.
[0004] To solve the above technical problems, the present application provides a control method for a microwave heating device, wherein the microwave heating device is provided with a power supply circuit, the power supply circuit comprising a rectifier circuit, a resonant circuit and an inverter circuit, the inverter circuit comprising a first switch tube, a second switch tube, a first unidirectional conduction tube arranged in parallel with the first switch tube, and a second unidirectional conduction tube arranged in parallel with the second switch tube, the rectifier circuit, the resonant circuit and the first switch tube are arranged in series with the second switch tube, and the conduction direction of the first unidirectional conduction tube is opposite to that of the second unidirectional conduction tube, and the control method comprises obtaining a target heating power of the microwave heating device; in response to the target heating power being less than a preset power, in each AC signal cycle, controlling one of the first switch tube and the second switch tube to work and the other to be disconnected, and adjusting the conduction time of the rectifier circuit to reduce the actual heating power to the target heating power.
[0005] In one embodiment, the control method further comprises adjusting a control parameter of one of the inverters when the other is in a working state; the control parameter comprises a driving frequency of the inverter circuit or a duty cycle of a pulse width modulation signal.
[0006] In one embodiment, in each AC signal cycle, one of the first switch tube and the second switch tube is controlled to work and the other is disconnected, including in two adjacent AC signal cycles, the first switch tube is controlled to be turned on and the second switch tube is controlled to be disconnected, or the second switch tube is controlled to be turned on and the first switch tube is controlled to be disconnected.
[0007] In one embodiment, in each AC signal cycle, one of the first switch tube and the second switch tube is controlled to work and the other is disconnected, including in the previous AC signal cycle, controlling the first switch tube to be turned on and controlling the second switch tube to be disconnected, and in the current AC signal cycle, controlling the second switch tube to be turned on and controlling the first switch tube to be disconnected.
[0008] In one embodiment, the control method also includes controlling the rectifier circuit to be turned on within the AC signal cycle and controlling both the first switch tube and the second switch tube to operate in response to the target heating power being greater than or equal to the preset power; adjusting the control parameters of the inverter circuit; the control parameters include the driving frequency of the inverter circuit or the duty cycle of the pulse width modulation signal to adjust the actual heating power to the target heating power.
[0009] In one embodiment, the rectifier circuit includes a bidirectional conductive controllable transistor, and the control method also includes performing zero-crossing detection on the AC signal input to the bidirectional conductive controllable transistor to determine the positive half-cycle and the negative half-cycle of the AC signal; adjusting the conduction time of the rectifier circuit, including shortening the conduction time of the bidirectional conductive controllable transistor in the positive half-cycle or shortening the conduction time of the bidirectional conductive controllable transistor in the negative half-cycle.
[0010] In order to solve the above technical problems, the present application provides a power supply circuit for a microwave heating device, the microwave heating device includes a control circuit and a power supply circuit electrically connected to the control circuit, the power supply circuit includes a rectifier circuit, a resonant circuit, an inverter circuit and a control circuit, the rectifier circuit is provided with a controllable tube, the controllable tube is used to turn on or off the rectifier circuit; the resonant circuit is connected to the rectifier circuit and the microwave generating circuit of the microwave heating device; the inverter circuit is connected in series between the resonant circuit and the rectifier circuit; wherein the inverter circuit includes a first switch tube, a second switch tube, a first unidirectional conduction tube arranged in parallel with the first switch tube, and a second unidirectional conduction tube arranged in parallel with the second switch tube, the first switch tube and the second switch tube are arranged in series, and the conduction directions of the first unidirectional conduction tube and the second unidirectional conduction tube are opposite; wherein the first switch tube, the second switch tube and the controllable tube are used to be electrically connected to the control circuit, so that the control circuit adopts the above control method to control the operation of the rectifier circuit and the inverter circuit, thereby controlling the heating power of the microwave generating circuit.
[0011] In one embodiment, the controllable transistor includes a bidirectional conductive controllable transistor.
[0012] In order to solve the above technical problems, the present application provides a microwave heating device, which includes the above-mentioned power supply circuit, control circuit and microwave generating circuit, the microwave generating circuit is electrically connected to the resonant circuit, and the control circuit adopts the above-mentioned control method to control the operation of the rectifier circuit and the inverter circuit to control the heating power of the microwave generating circuit.
[0013] In order to solve the above technical problems, the present application provides a computer storage medium, which stores computer program instructions, and the computer program instructions can be executed by a processor to execute the above control method.
[0014] The beneficial effects of the present application are as follows: the control method of the present application obtains the target heating power required by the user, and when the target heating power is less than the preset power, firstly, in each AC signal cycle, the first switch tube or the second switch tube is controlled to work to perform a first-level adjustment to reduce the actual heating power of the microwave heating device, and then the conduction time of the rectifier circuit is adjusted to perform a second-level adjustment to further reduce the actual heating power to the target heating power. That is, the control method of the present application can realize the two-level power adjustment of the microwave heating device, and the actual heating power can be further reduced by adjusting the conduction time of the rectifier circuit, so that the lower limit of the actual heating power will not be restricted by the hardware of the inverter circuit, and the low-power heating demand of the user can be met; in addition, the present application can adjust the conduction time of the first switch tube or the second switch tube and the rectifier circuit to realize the power adjustment of the microwave heating device, which can improve the problem that the heating power adjustment amplitude is too large due to adjusting only one factor, thereby reducing the reliability of the corresponding device, and thus improve the adjustment accuracy of the target heating power. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work, among which:
[0016] Figure 1 It is a structural schematic diagram of an embodiment of a microwave heating device provided by the present application;
[0017] Figure 2 is a circuit diagram of an embodiment of a microwave heating device provided by the present application;
[0018] Figure 3 It is a flow chart of an embodiment of a control method for a microwave heating device provided by the present application;
[0019] Figure 4 is a flow chart of another embodiment of the control method of the microwave heating device provided by the present application;
[0020] Figure 5 It is a signal timing diagram provided by this application;
[0021] Figure 6 It is a structural diagram of an embodiment of a computer storage medium provided by the present application. DETAILED DESCRIPTION
[0022] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0023] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.
[0024] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.
[0025] The present application provides a microwave heating device, referring to Figure 1 , Figure 1 1 is a schematic diagram of the structure of an embodiment of a microwave heating device provided by the present application, wherein the microwave heating device 10 comprises a body 300, a power supply circuit 100, a microwave generating circuit 200 and a control circuit 400, wherein the power supply circuit 100 is electrically connected to the control circuit 400 and the microwave generating circuit 200 respectively, and the power supply circuit 100, the control circuit 400 and the microwave generating circuit 200 are arranged in the body 300. The control circuit 400 controls the heating power of the microwave generating circuit 200 by controlling the power supply circuit 100 to work, thereby controlling the heating power of the microwave heating device 10.
[0026] Among them, the microwave heating device 10 can include microwave ovens, microwave steam ovens, microwave fryers, microwave rice steamers, microwave heating stoves and other microwave heating devices, which are not limited here.
[0027] In one embodiment, see Figure 2 , Figure 21 is a circuit diagram of an embodiment of a microwave heating device provided by the present application, wherein the power supply circuit 100 includes a rectifier circuit 110, an inverter circuit 120, a resonant circuit 130 and a control circuit 400. The rectifier circuit 110 is provided with a controllable tube (not marked in the figure), which is used to turn on or off the rectifier circuit 110. The resonant circuit 130 is connected to the rectifier circuit 110 and the microwave generating circuit 200. The inverter circuit 120 is connected in series between the resonant circuit 130 and the rectifier circuit 110. The control circuit 400 is connected to the control end of the controllable tube and the inverter circuit 120. Among them, the inverter circuit 120 includes a first switch tube Q21, a second switch tube Q22, a first unidirectional conduction tube D21 arranged in parallel with the first switch tube Q21, and a second unidirectional conduction tube D22 arranged in parallel with the second switch tube Q22. The first end of the first switch tube Q21 is connected to the resonant circuit 130 and the cathode of the first unidirectional guide tube D21, the second end of the first switch tube Q21 is connected to the first end of the second switch tube Q22, the anode of the first unidirectional guide tube D21 and the cathode of the second unidirectional guide tube D22, the control end of the first switch tube Q21 is connected to the control circuit 400; the second end of the second switch tube Q22 is connected to the cathode of the second unidirectional guide tube D22, and the second end of the second switch tube Q22 is grounded; the control end of the second switch tube Q22 is connected to the control circuit 400. The control circuit 400 controls the operation of the rectifier circuit 110 and the inverter circuit 120, and can adjust the bus voltage of the power supply circuit 100, thereby adjusting the heating power of the microwave heating device 10.
[0028] Specifically, when the inverter circuit 120 is in a working state, in the positive half cycle of the AC signal, the first switch tube Q21 is in a working state, and the second switch tube Q22 is in a cut-off state. At this time, the branch where the first switch tube Q21 and the second unidirectional conduction tube D22 are located is turned on; in the negative half cycle of the AC signal, the first switch tube Q21 is in a cut-off state, and the second switch tube Q22 is in a working state. At this time, the second switch tube Q22 and the branch where the first unidirectional conduction tube D21 is located are turned on.
[0029] In one embodiment, the rectifier circuit 110 includes a bidirectional thyristor diode (not marked in the figure). The rectifier circuit 110 of this embodiment is a bridgeless stack design, which can reduce the number of electronic components of the rectifier circuit 110 and reduce switching losses.
[0030] In one embodiment, the power supply circuit 100 also includes a zero-crossing detection circuit 140, and the zero-crossing detection circuit 140 is used to detect the zero-crossing signal of the AC signal. Specifically, the zero-crossing detection circuit 140 includes a first zero-crossing detection circuit (not marked in the figure) and a second zero-crossing detection circuit (not marked in the figure). Among them, the first zero-crossing detection circuit is respectively connected to the access end of the positive half-cycle in the AC signal of the rectifier circuit 110 and the control circuit 400, and the first zero-crossing detection circuit is used to detect the zero-crossing signal of the positive half-cycle signal, and outputs a positive phase zero-point signal to the control circuit 400. The second zero-crossing detection circuit is respectively connected to the access end of the negative half-cycle in the AC signal of the rectifier circuit 110 and the control circuit 400, and the second zero-crossing detection circuit is used to detect the zero-crossing signal of the negative half-cycle signal, and outputs an inverted zero-point signal to the control circuit 400. For example, the first zero-crossing detection circuit is connected to the live wire, and the second zero-crossing detection circuit is connected to the neutral wire. Among them, the zero-crossing detection circuit 140 can be an integrated zero-crossing detection circuit, or a conventional zero-crossing detection circuit, which is not limited here.
[0031] In one embodiment, the power supply circuit 100 further includes a filter capacitor C1 , one end of the filter capacitor C1 is connected to the rectifier circuit 110 , and the other end of the filter capacitor C1 is grounded.
[0032] In one embodiment, the resonant circuit 130 includes a resonant capacitor C31 and a transformer L31. The resonant capacitor C31 is connected in parallel with the primary coil of the transformer L31 and then connected in series between the rectifier circuit 110 and the inverter circuit 120. The secondary coil of the transformer L31 is connected to the microwave generating circuit 200.
[0033] In one embodiment, the microwave generating circuit 200 includes a voltage doubler circuit 201 and a magnetron 202 . The voltage doubler circuit 201 is connected to the secondary coil of the transformer L31 to generate a voltage for driving the magnetron 202 .
[0034] In other embodiments, the microwave generating circuit 200 may include a semiconductor device, a module, an integrated circuit, etc. for generating microwaves, which is not limited herein.
[0035] In one embodiment, the control circuit 400 includes a processor (not shown) and peripheral circuits for maintaining normal operation of the processor. The processor may be an integrated circuit chip with signal processing capabilities. The processor may also be a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array (FPGA) or other programmable logic devices. The general-purpose processor may also be a microprocessor or the processor may also be any conventional processor, etc.
[0036] In one embodiment, an independent second control circuit (not marked in the figure) may be provided in the power supply circuit 100, and the second control circuit is electrically connected to the control circuit 400 of the microwave heating device 10, and the control circuit 400 controls the operation of the power supply circuit 100 by controlling the operation of the second control circuit.
[0037] In one embodiment, the control parameter of the inverter circuit 120 may be the driving frequency of the first switch tube Q21 and the second switch tube Q22, or the duty cycle of the pulse width modulation signal of the first switch tube Q21 and the second switch tube Q22, or the driving frequency of the first switch tube Q21 and the second switch tube Q22 and the duty cycle of the pulse width modulation signal.
[0038] Among them, because the driving frequency needs to meet When the driving frequency of the first switch tube Q21 or the second switch tube Q22 or the duty cycle of the pulse width modulation signal is adjusted to a certain degree, the limitation of the inherent frequency of the first switch tube Q21 or the second switch tube Q22 causes the first switch tube Q21 and the second switch tube Q22 to be unable to execute the driving frequency or the duty cycle of the pulse width modulation signal. Therefore, the heating power of the microwave generating circuit 200 cannot be further increased or reduced. If the user needs to heat at a power lower than the minimum power that the first switch tube Q21 or the second switch tube Q22 can achieve, the user's needs cannot be met by changing the control parameters of the first switch tube Q21 or the second switch tube Q22. In order to solve the above technical problems, the present application proposes a control method applied to the above microwave heating device 10 in combination with the above microwave heating device 10 to meet the user's low-power heating needs.
[0039] See also Figure 3 , Figure 3 1 is a flow chart of an embodiment of a control method for a microwave heating device provided by the present application, and the control method comprises the following steps:
[0040] Step S100: obtaining the target heating power of the microwave heating device.
[0041] When a user uses a microwave heating device, the user inputs a target heating power. The target heating power may be a heating power input by the user, or may be a heating power corresponding to a heating mode input by the user, which is not limited here. The target heating power may be a specific value or a range of values, which is not limited here.
[0042] Step S200: In response to the target heating power being less than the preset power, in each AC signal cycle, one of the first switch tube and the second switch tube is controlled to operate and the other is disconnected, and the conduction time of the rectifier circuit is adjusted to reduce the actual heating power to the target heating power.
[0043] The user's heating needs can be identified by the preset power. For example, if the target heating power is greater than or equal to the preset power, it is considered that the user has a high-power heating demand, and if the target heating power is less than the preset power, it is considered that the user has a low-power heating demand. The preset power can be a fixed power value in the microwave heating device; the microwave heating device can be set with multiple preset powers, and the user can choose to set a specific preset power based on demand or the control circuit can choose to set a specific preset power based on user usage habits.
[0044] After obtaining the target heating power, the target heating power is compared with the preset power to determine the user's heating needs. When the target heating power is less than the preset power, in each AC signal cycle, one of the first switch tube and the second switch tube is controlled to work and the other is disconnected. At this time, in the AC signal cycle, the first switch tube can be controlled to work in the positive half cycle of the AC signal, and the second switch tube can be disconnected, that is, the inverter circuit only works in the positive half cycle in the AC signal cycle; or, the first switch tube is controlled to be disconnected in the negative half cycle of the AC signal, and the second switch tube is controlled to work, that is, the inverter circuit only works in the negative half cycle in the AC signal cycle, which is not limited here. It can be known that the inverter circuit only works for half a cycle, which can reduce the bus voltage of the power supply circuit, thereby reducing the actual heating power of the microwave heating device; in addition, further adjusting the conduction time of the rectifier circuit to further reduce the output voltage of the power supply circuit to adjust the actual heating power can further reduce the actual heating power to the target heating power.
[0045] In one embodiment, the preset power includes 500W-1000W. Existing microwave heating equipment mainly focuses on high-power heating, and its minimum heating power can be as low as 500W. The specific value of the preset power can be set according to the minimum heating power that can be achieved by the inverter switch, for example, the preset power can be 500W, 600W, 650W, 800W, 1000W, etc.
[0046] The control method of the present application obtains the target heating power required by the user, and when the target heating power is less than the preset power, in each AC signal cycle, the first switch tube or the second switch tube is controlled to work to perform a first-level adjustment, so as to reduce the actual heating power of the microwave heating device by reducing the bus voltage of the power supply circuit, and further adjusts the conduction time of the rectifier circuit to perform a second-level adjustment, so as to further reduce the output voltage of the power supply circuit and further reduce the actual heating power to the target heating power. That is, the control method of the present application can realize the two-level power regulation of the microwave heating device, and can further reduce the actual heating power by adjusting the conduction time of the rectifier circuit, so that the lower limit of the actual heating power will not be restricted by the hardware of the inverter circuit, and can meet the user's low-power heating needs; in addition, the present application can adjust the conduction time of the first switch tube or the second switch tube and the rectifier circuit to realize the power regulation of the microwave heating device, which can improve the problem that the heating power adjustment amplitude is too large due to adjusting only one factor, thereby reducing the reliability of the corresponding device, and thus can improve the adjustment accuracy of the target heating power.
[0047] In one embodiment, in step S200, in each AC signal cycle, controlling one of the first switch tube and the second switch tube to operate and the other to be disconnected can be achieved by the following steps:
[0048] Step S201: in two adjacent AC signal cycles, the first switch tube is controlled to operate and the second switch tube is controlled to be disconnected, or the second switch tube is controlled to operate and the first switch tube is controlled to be disconnected.
[0049] It can be understood that, in two adjacent AC signal cycles, only the first switch tube is controlled to be in the working state, and the second switch tube is controlled to be in the cut-off state. At this time, the branch where the first switch tube and the second unidirectional conductive tube are located is only turned on in the positive half cycle of the AC signal. Alternatively, in two adjacent AC signal cycles, only the second switch tube is controlled to be in the working state, and the first switch tube is controlled to be in the cut-off state. At this time, the branch where the second switch tube and the first unidirectional conductive tube are located is only turned on in the negative half cycle of the AC signal.
[0050] In this embodiment, in two adjacent AC signal cycles, the first switch tube is controlled to work and the second switch tube is controlled to be disconnected, or the second switch tube is controlled to work and the first switch tube is controlled to be disconnected, so that the inverter circuit only works in half a cycle of the AC signal, which can reduce the bus voltage of the power supply circuit and thus reduce the actual heating power; in addition, in adjacent AC signal cycles, the first switch tube or the second switch tube is controlled to work, and the corresponding other switch tube is turned off, which can reduce the switching loss of the switch tube.
[0051] For example, during the adjustment or heating process, only the first switch tube is controlled to work in the positive half cycle of the AC signal and the second switch tube is controlled to be disconnected. Alternatively, during the adjustment or heating process, only the second switch tube is controlled to work in the negative half cycle of the AC signal and the first switch tube is controlled to be disconnected.
[0052] In one embodiment, in step S200, in each AC signal cycle, controlling one of the first switch tube and the second switch tube to operate and the other to be disconnected can be achieved by the following steps:
[0053] Step S202: in the previous AC signal cycle, the first switch tube is controlled to work and the second switch tube is controlled to be turned off; in the current AC signal cycle, the second switch tube is controlled to be turned on and the first switch tube is controlled to be turned off.
[0054] In the previous AC signal cycle, only the first switch tube is controlled to be in the working state, and the second switch tube is controlled to be in the cut-off state. At this time, the branch where the first switch tube and the second unidirectional conduction tube are located is only turned on in the positive half cycle of the AC signal; in the current AC signal cycle, only the second switch tube is controlled to be in the working state, and the first switch tube is controlled to be in the cut-off state. At this time, the branch where the second switch tube and the first unidirectional conduction tube are located is only turned on in the negative half cycle of the AC signal. Therefore, in two adjacent AC signal cycles, different branches of the inverter circuit work alternately, which can balance the switching losses of the first switch tube and the second switch tube.
[0055] In other embodiments, in the same AC signal cycle, the first switch tube and the second switch tube work in the positive half cycle and the negative half cycle of the AC signal respectively, wherein the total working time of the first switch tube and the second switch tube is equal to the working time of the inverter circuit for only half a cycle. The working time of the first switch tube and the second switch tube in the positive half cycle and the negative half cycle respectively may be equal or unequal, which is not limited here.
[0056] In one embodiment, continue to refer to Figure 3 , the control method further includes:
[0057] Step S300: In response to the target heating power being greater than or equal to the preset power, the rectifier circuit is controlled to be turned on during the AC signal cycle, and both the first switch tube and the second switch tube are controlled to operate.
[0058] When the target heating power is greater than or equal to the preset power, the actual heating power needs to be increased. Therefore, the rectifier circuit is controlled to be turned on during the AC signal cycle, and the rectifier circuit is in a normally on state. At the same time, both the first switch tube and the second switch tube are controlled to work, that is, the first switch tube and the second switch tube are controlled to work alternately in the positive half cycle and the negative half cycle in the same AC signal cycle.
[0059] Step S400: adjusting control parameters of the inverter circuit, the control parameters including the driving frequency of the inverter circuit or the duty cycle of the pulse width modulation signal, so as to adjust the actual heating power to the target heating power.
[0060] The control parameters include the driving frequency of the inverter circuit, or include or the duty cycle of the pulse width modulation signal, or include the driving frequency and the duty cycle of the pulse width modulation signal. The first switch tube and the second switch tube are controlled to work alternately in the positive half cycle and the negative half cycle in the same AC signal cycle. At the same time, the control parameters of the inverter circuit are adjusted, that is, the control parameters of the first switch tube and the second switch tube are adjusted. By adjusting the driving frequency of the first switch tube and the second switch tube or the duty cycle of the pulse width modulation signal, the bus voltage of the power supply circuit can be increased, and the actual heating power can be further increased, so that the actual heating power is adjusted to the target heating power, and the user's high-power heating demand is achieved. For example, the driving frequency of the first switch tube is adjusted, or the duty cycle of the pulse width modulation signal of the first switch tube is adjusted, or the driving frequency of the first switch tube and the duty cycle of the pulse width modulation signal are adjusted at the same time. There is a second switch tube in the same way. Among them, the order of driving frequency adjustment and duty cycle adjustment can be not limited. The specific amplitude and number of control parameter adjustments can be determined based on factors such as the target heating power, the actual heating power, and the hardware and software performance of the microwave heating equipment.
[0061] In this embodiment, when the target heating power is greater than or equal to the preset power, the rectifier circuit is controlled to be in a long conduction state, and within the same AC signal cycle, the first switch tube and the second switch tube are controlled to alternately operate in the positive half cycle and the negative half cycle, and the driving frequency of the first switch tube and the second switch tube or the duty cycle of the pulse width modulation signal are adjusted at the same time, which can increase the bus voltage of the power supply circuit and increase the actual heating power to meet the user's high-power heating needs.
[0062] In one embodiment, in order to achieve precise regulation of the target heating power, when the target heating power is greater than or equal to the preset power, within the same AC signal cycle, the first switch tube and the second switch tube can be controlled to alternately operate in the positive half cycle and the negative half cycle of the AC signal to achieve primary regulation of the target heating power. The control parameters of the first switch tube and the second switch tube can also be adjusted to achieve secondary regulation of the target heating power. The conduction time of the rectifier circuit within the AC cycle can be further adjusted to achieve tertiary regulation of the target heating power. The power regulation of the microwave heating equipment can be achieved by adjusting the working time of the inverter circuit, the driving frequency, the duty cycle of the pulse width modulation signal, and the conduction time of the rectifier circuit within the AC cycle. This can improve the problem of excessive heating power adjustment due to adjusting only one or two factors, thereby reducing the reliability of the corresponding device, and thus improve the regulation accuracy of the target heating power.
[0063] In one embodiment, see Figure 4, Figure 4 1 is a flow chart of another embodiment of a control method for a microwave heating device provided by the present application, the method further comprising:
[0064] Step S500: When one of the inverters is in working state, adjusting a control parameter of the inverter; the control parameter includes a driving frequency of the inverter circuit or a duty cycle of a pulse width modulation signal.
[0065] In order to further adjust the bus voltage of the power supply circuit, when the first switch tube or the second switch tube is in a working state, the control parameters of the first switch tube or the second switch tube are adjusted, for example, the driving frequency of the first switch tube or the second switch tube is adjusted, or the duty cycle of the pulse width modulation signal of the first switch tube or the second switch tube is adjusted; or the driving frequency of the first switch tube or the second switch tube and the duty cycle of the pulse width modulation signal are adjusted at the same time.
[0066] In one embodiment, the rectifier circuit includes a bidirectional conductive controllable transistor, and the control method further includes the following steps:
[0067] Step S600: performing zero-crossing detection on the AC signal input to the bidirectionally conductive controllable transistor to determine the positive half-cycle and the negative half-cycle of the AC signal.
[0068] In order to accurately control the operation of the first switch tube and the second switch tube and the conduction time of the rectifier circuit, zero-crossing detection is performed on the AC signal to determine the positive half cycle and the negative half cycle of the AC signal.
[0069] It is worth noting that step S600 is obtained before controlling the first switch tube or the second switch tube to work, or before adjusting the conduction time of the rectifier circuit, which is not limited here.
[0070] Wherein, adjusting the conduction time of the rectifier circuit includes:
[0071] Step S203: shortening the conduction time of the bidirectionally conductive controllable transistor in the positive half cycle or shortening the conduction time of the bidirectionally conductive controllable transistor in the negative half cycle.
[0072] Adjusting the conduction time of the rectifier circuit in the AC signal cycle can specifically shorten the conduction time of the bidirectional conductive controllable tube in the positive half cycle, or shorten the conduction time of the bidirectional conductive controllable tube in the negative half cycle, or shorten the conduction time of the bidirectional conductive controllable tube in both the positive half cycle and the negative half cycle. When shortening the conduction time of the bidirectional conductive controllable tube in the positive half cycle and the negative half cycle, the conduction time of the bidirectional conductive controllable tube can be the same or different, which is not limited here.
[0073] This embodiment realizes the rectification function by setting a bidirectional conductive controllable tube, and has few components and a simple structure. In addition, the positive half-cycle and the negative half-cycle of the AC signal are determined by zero-crossing detection to shorten the conduction time of the bidirectional conductive controllable tube in the positive half-cycle or shorten the conduction time of the bidirectional conductive controllable tube in the negative half-cycle, which can shorten the conduction time of the rectification circuit, thereby reducing the output voltage of the power supply circuit, and further adjusting the actual heating power of the microwave heating device.
[0074] For example, the AC signal cycle is S, and the conduction time of the rectifier circuit in the AC signal cycle is T. If the conduction time T is less than or equal to 1 / 2S, only the conduction time of the bidirectional conductive controllable tube in the positive half cycle can be controlled to be T1, at this time T1=T; or only the conduction time of the bidirectional conductive controllable tube in the negative half cycle can be controlled to be T2, at this time T2=T; or the conduction time of the bidirectional conductive controllable tube in the positive half cycle can be controlled to be T1, and the conduction time of the bidirectional conductive controllable tube in the negative half cycle can be controlled to be T2, at this time T1+T2=T, wherein T1 and T2 can be equal or unequal, and are not limited here. If T is greater than 1 / 2S and T is less than S, the conduction time of the bidirectional conductive controllable tube in the positive half cycle can be controlled to be T1, and the conduction time of the bidirectional conductive controllable tube in the negative half cycle can be controlled to be T2, at this time T1+T2=T, wherein T1 and T2 can be equal or unequal, and are not limited here.
[0075] In one embodiment, the conduction time of the bidirectional conductive controllable transistor in the positive half cycle is the same as the conduction time of the bidirectional conductive controllable transistor in the negative half cycle, and the conduction moments of the bidirectional conductive controllable transistor in the positive half cycle and the negative half cycle in the same AC signal cycle are continuous, which can reduce the switching loss of the bidirectional conductive controllable transistor.
[0076] In one embodiment, the conduction time of the bidirectional conductive controllable transistor is symmetrical with the time point corresponding to the peak of the AC signal in the positive half cycle as the midpoint. The conduction time of the bidirectional conductive controllable transistor is symmetrical with the time point corresponding to the trough of the AC signal in the negative half cycle as the midpoint. Figure 5 , Figure 5 This is a signal timing diagram provided by the present application. It can be understood that in the positive half cycle of the AC signal, the conduction interval of the bidirectional conductive controllable tube corresponds to the time point corresponding to the peak of the positive half cycle, which is a midpoint symmetrical interval. In the negative half cycle of the AC signal, the conduction interval of the bidirectional conductive controllable tube corresponds to the time point corresponding to the trough of the negative half cycle, which is a midpoint symmetrical interval.
[0077] The present application provides a computer storage medium, referring to Figure 6 , Figure 61 is a structural diagram of an embodiment of a computer storage medium provided in the present application, wherein the computer storage medium 20 stores computer program instructions 21, and the computer program instructions 21 can be executed by a processor to execute a control method for a microwave heating device, wherein the control method for a microwave heating device is any one of the control method embodiments for the microwave heating device described above, which will not be described in detail herein.
[0078] The above are only implementation methods of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.
Claims
1. A control method for a microwave heating device, characterized in that: The microwave heating device is provided with a power supply circuit, the power supply circuit includes a rectifier circuit, a resonant circuit and an inverter circuit, the inverter circuit includes a first switch tube, a second switch tube, a first unidirectional conduction tube arranged in parallel with the first switch tube, and a second unidirectional conduction tube arranged in parallel with the second switch tube, the rectifier circuit, the resonant circuit and the first switch tube are arranged in series with the second switch tube, the conduction direction of the first unidirectional conduction tube is opposite to that of the second unidirectional conduction tube, and the control method includes: Obtaining a target heating power of the microwave heating device; In response to the target heating power being less than the preset power, in each AC signal cycle, one of the first switch tube and the second switch tube is controlled to work and the other is disconnected, and the conduction time of the rectifier circuit is adjusted to reduce the actual heating power to the target heating power.
2. The control method according to claim 1, characterized in that: The control method further comprises: When one of the inverters is in working state, a control parameter of the one of the inverters is adjusted; the control parameter includes a driving frequency of the inverter circuit or a duty cycle of a pulse width modulation signal.
3. The control method according to claim 1, characterized in that: The method of controlling one of the first switch tube and the second switch tube to operate and the other to be disconnected in each AC signal cycle includes: In two adjacent cycles of the AC signal, the first switch tube is controlled to operate and the second switch tube is controlled to be disconnected, or the second switch tube is controlled to operate and the first switch tube is controlled to be disconnected.
4. The control method according to claim 1, characterized in that: The method of controlling one of the first switch tube and the second switch tube to operate and the other to be disconnected in each AC signal cycle includes: In the previous AC signal cycle, the first switch tube is controlled to be turned on and the second switch tube is controlled to be turned off. In the current AC signal cycle, the second switch tube is controlled to be turned on and the first switch tube is controlled to be turned off.
5. The control method according to claim 1, characterized in that: The control method further comprises: In response to the target heating power being greater than or equal to the preset power, controlling the rectifier circuit to be turned on during the AC signal cycle, and controlling both the first switch tube and the second switch tube to operate; Adjusting control parameters of the inverter circuit; the control parameters include the driving frequency of the inverter circuit or the duty cycle of the pulse width modulation signal, so as to adjust the actual heating power to the target heating power.
6. The control method according to claim 1, characterized in that: The rectifier circuit includes a bidirectional conductive controllable tube, and the control method further includes: Performing zero-crossing detection on the AC signal input to the bidirectional conductive controllable tube to determine the positive half-cycle and the negative half-cycle of the AC signal; The adjusting the conduction time of the rectifier circuit includes: The conduction time of the bidirectional conductive controllable transistor in the positive half cycle is shortened, or the conduction time of the bidirectional conductive controllable transistor in the negative half cycle is shortened.
7. A power supply circuit, characterized in that: Used in a microwave heating device, the microwave heating device comprises a control circuit and a power supply circuit electrically connected to the control circuit, the power supply circuit comprising: A rectifier circuit is provided with a controllable tube, and the controllable tube is used to turn on or off the rectifier circuit; A resonant circuit connected to the rectifier circuit and the microwave generating circuit of the microwave heating device; An inverter circuit connected in series between the resonant circuit and the rectifier circuit; The inverter circuit includes a first switch tube, a second switch tube, a first unidirectional conduction tube arranged in parallel with the first switch tube, and a second unidirectional conduction tube arranged in parallel with the second switch tube, the first switch tube and the second switch tube are arranged in series, and the conduction directions of the first unidirectional conduction tube and the second unidirectional conduction tube are opposite; Wherein, the first switching tube, the second switching tube and the controllable tube are used to be electrically connected to the control circuit, so that the control circuit adopts the control method described in any one of claims 1 to 6 to control the operation of the rectifier circuit and the inverter circuit, thereby controlling the heating power of the microwave generating circuit.
8. The power supply circuit according to claim 7, characterized in that: The controllable tube includes a bidirectional conductive controllable tube.
9. A microwave heating device, characterized in that: include: The power supply circuit, control circuit and microwave generating circuit described in any one of claims 7-8, wherein the microwave generating circuit is electrically connected to the resonant circuit, and the control circuit adopts the control method described in any one of claims 1 to 6 to control the operation of the rectifier circuit and the inverter circuit to control the heating power of the microwave generating circuit.
10. A computer storage medium, characterized in that: The computer storage medium stores computer program instructions, and the computer program instructions can be executed by a processor to perform the control method according to any one of claims 1 to 6.