Control method for microwave heating device, and power supply circuit, microwave heating device, and computer storage medium

Abstract

Provided in the present application are a control method for a microwave heating device, and a power supply circuit, a microwave heating device, and a computer storage medium. The microwave heating device is provided with a power supply circuit, wherein the power supply circuit comprises a rectifier circuit and an inverter switch. The control method comprises: acquiring a target heating power of a microwave heating device; in response to the target heating power being less than a preset power, adjusting control parameters of an inverter switch, so as to adjust an actual heating power of the microwave heating device to the preset power; and in response to the actual heating power reaching the preset power, reducing a conduction duration of a rectifier circuit within an alternating-current signal cycle, so as to reduce the actual heating power to the target heating power. The control method for a microwave heating device provided by the present application can realize low-power heating of microwave heating devices.

Description

Control methods for microwave heating equipment, power supply circuits, microwave heating equipment, and computer storage media.

[0001] This application claims priority to Chinese Patent Application No. 202411517866.X, filed on October 28, 2024, entitled "Control Method, Power Supply Circuit, Microwave Heating Equipment, and Computer Storage Medium for Microwave Heating Equipment", the entirety of which is incorporated herein by reference. [Technical Field]

[0002] This application relates to the field of home appliance technology, and in particular to a control method, power supply circuit, microwave heating device, and computer storage medium for a microwave heating device. [Background Technology]

[0003] Microwave heating equipment, as a type of heating device, can achieve rapid heating, which is convenient and quick. However, existing microwave heating equipment, such as microwave ovens, typically use high-power heating to achieve rapid heating, which cannot meet users' needs for low-power heating, such as less than 500W. [Summary of the Invention]

[0004] This application provides a control method, power supply circuit, microwave heating equipment, and computer storage medium for a microwave heating device, in order to solve the technical problem that existing microwave heating devices cannot perform low-power heating.

[0005] To address the aforementioned technical problems, this application provides a control method for a microwave heating device. The microwave heating device includes a power supply circuit comprising a rectifier circuit and an inverter switch. The control method includes acquiring a target heating power of the microwave heating device; adjusting the control parameters of the inverter switch to adjust the actual heating power of the microwave heating device to the preset power in response to the target heating power being less than a preset power; and reducing the conduction time of the rectifier circuit within the AC signal cycle to reduce the actual heating power to the target heating power in response to the actual heating power reaching the preset power.

[0006] In one embodiment, the rectifier circuit includes a rectifier bridge, and the control method further includes zero-crossing detection of the AC signal input to the rectifier bridge to determine the positive half-cycle and negative half-cycle of the AC signal; reducing the conduction time of the rectifier circuit during the AC signal cycle, including shortening the conduction time of the upper bridge arm of the rectifier bridge during the positive half-cycle or shortening the conduction time of the lower bridge arm of the rectifier bridge during the negative half-cycle.

[0007] In one embodiment, the conduction time of the upper bridge arm is symmetrical with respect to the time point corresponding to the peak of the AC signal in the positive half-cycle as the midpoint; the conduction time of the lower bridge arm is symmetrical with respect to the time point corresponding to the trough of the AC signal in the negative half-cycle as the midpoint.

[0008] In one embodiment, the conduction duration of the upper bridge arm is the same as that of the lower bridge arm.

[0009] In one embodiment, in response to the actual heating power reaching a preset power, the conduction time of the rectifier circuit during the AC signal cycle is reduced to decrease the actual heating power to the target heating power. This includes reducing the conduction time of the rectifier circuit during the AC signal cycle and adjusting the control parameters of the inverter switch in response to the actual heating power reaching the preset power to decrease the actual heating power to the target heating power.

[0010] In one embodiment, the control method further includes adjusting the control parameters of the inverter switch in response to the target heating power being greater than or equal to a preset power, so as to adjust the actual heating power of the microwave heating device to the target heating power; wherein the control parameters include the drive frequency of the inverter switch or the duty cycle of the pulse width modulation signal.

[0011] In one embodiment, the control method further includes: acquiring an initial power; in response to the initial power being greater than or equal to a preset power, performing the steps of adjusting the control parameters of the inverter switch to adjust the actual heating power of the microwave heating device to the preset power in response to the target heating power being less than the preset power; and reducing the conduction time of the rectifier circuit in the AC signal cycle to reduce the actual heating power to the target heating power in response to the actual heating power reaching the preset power; and adjusting the conduction time of the rectifier circuit in the AC signal cycle to adjust the actual heating power to the target heating power in response to the initial power being less than the preset power.

[0012] In one embodiment, the preset power range is 500W-1000W.

[0013] To address the aforementioned technical problems, this 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 and an inverter switch. At least one arm of the rectifier circuit is provided with a controllable transistor, which is used to turn on the corresponding arm. The inverter switch is electrically connected to the rectifier circuit and the microwave generating circuit of the microwave heating device. The controllable transistor and the inverter switch are electrically connected to the control circuit so that the control circuit can control the rectifier circuit and the inverter switch to operate using the aforementioned control method, thereby controlling the heating power of the microwave generating circuit.

[0014] To solve the above-mentioned technical problems, this 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 inverter switch. The control circuit uses the above-mentioned control method to control the operation of the rectifier circuit and the inverter switch, so as to control the heating power of the microwave generating circuit.

[0015] To solve the above-mentioned technical problems, this application provides a computer storage medium that stores computer program instructions, which can be executed by a processor to perform the above-mentioned control method.

[0016] The beneficial effects of this application are as follows: The control method for the microwave heating equipment of this application obtains the target heating power required by the user. When the target heating power is less than the preset power, it first performs a primary adjustment by adjusting the control parameters of the inverter switch to adjust the actual heating power of the microwave heating equipment to the preset power. After the actual heating power is adjusted to the preset power, a secondary adjustment is performed by reducing the conduction time of the rectifier circuit within the AC signal cycle to further adjust the actual heating power to the target heating power. That is, the control method of this application can realize two-stage power regulation of the microwave heating equipment, and can further reduce the actual heating power by reducing the conduction time of the rectifier circuit within the AC signal cycle. The lower limit of the actual heating power is not constrained by the lower limit of the control parameters of the inverter switch under normal operating conditions, which can meet the user's low-power heating needs. [Attached Image Description]

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0018] Figure 1 is a structural schematic diagram of an embodiment of the microwave heating device provided in this application;

[0019] Figure 2 is a circuit diagram of an embodiment of the microwave heating device provided in this application;

[0020] Figure 3 is a circuit diagram of another embodiment of the microwave heating device provided in this application;

[0021] Figure 4 is a flowchart illustrating an embodiment of the control method for the microwave heating device provided in this application.

[0022] Figure 5 is a flowchart illustrating step S400 of the embodiment in Figure 4.

[0023] Figure 6 is a signal timing diagram provided in this application;

[0024] Figure 7 is a flowchart illustrating another embodiment of the control method for the microwave heating equipment provided in this application;

[0025] Figure 8 is a flowchart illustrating step S300 of the embodiment in Figure 4.

[0026] Figure 9 is a schematic diagram of an embodiment of the computer storage medium provided in this application.

Detailed Implementation Methods

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] The terms "first" and "second" in this application are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly defined. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices. The term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects are in an "or" relationship.

[0029] This application provides a microwave heating device. Referring to FIG1, FIG1 is a structural schematic diagram of an embodiment of the microwave heating device provided in this application. The microwave heating device 10 includes a body 300, a power supply circuit 100, a microwave generating circuit 200, and a control circuit 400. The power supply circuit 100 is electrically connected to the control circuit 400 and the microwave generating circuit 200, and the power supply circuit 100, the control circuit 400, and the microwave generating circuit 200 are disposed in the body 300. The control circuit 400 controls the operation of the power supply circuit 100 to control the heating power of the microwave generating circuit 200, thereby controlling the heating power of the microwave heating device 10.

[0030] Among them, microwave heating equipment 10 may include microwave ovens, microwave steam ovens, microwave fryers, microwave rice steamers, microwave heating stoves and other microwave heating equipment, which are not limited here.

[0031] In one embodiment, referring to FIG2, FIG2 is a circuit diagram of an embodiment of the microwave heating device provided in this application. The power supply circuit 100 includes a rectifier circuit 110 and an inverter switch Q21. The rectifier circuit 110 is connected to an AC signal, and at least one arm of the rectifier circuit 110 is provided with a controllable transistor, which is used to turn on the corresponding arm. The inverter switch Q21 is electrically connected to the rectifier circuit 110 and the microwave generating circuit 200. The control circuit 400 is electrically connected to the controllable transistor and the inverter switch Q21, and the control circuit 400 controls the operation of the controllable transistor and the inverter switch Q21 to control the microwave generating circuit 200 to generate microwaves. The control circuit 400 can adjust the heating power of the microwave heating device 10 by adjusting the conduction time of the controllable transistor and the control parameters of the inverter switch Q21.

[0032] In one embodiment, continuing to refer to FIG2, the rectifier circuit 110 includes a rectifier bridge composed of diodes D11 and D12, and controllable transistors T11 and T12, wherein diodes D12 and T11 form one bridge arm, and diodes D11 and T12 form the other bridge arm. In other embodiments, diodes D11 and D12 form one bridge arm of the rectifier bridge, and controllable transistors T11 and T12 form the other bridge arm. In other embodiments, the rectifier circuit 110 may further include a rectifier bridge composed of three diodes and one controllable transistor, or a rectifier bridge composed of four controllable transistors, or the rectifier bridge may include four diodes and at least one controllable transistor. The controllable transistor can be placed in any bridge arm to conduct or cut off the corresponding bridge arm, which is not limited here. The control circuit 400 can adjust the conduction time of the rectifier circuit 110 by adjusting the conduction time of the controllable transistor, thereby reducing the output voltage.

[0033] In other embodiments, the rectifier circuit 110 may further include a bidirectional controllable transistor (not shown in the figure), which can realize the rectification function of the full-bridge rectifier. In this embodiment, the rectifier circuit 110 includes only a bidirectional controllable transistor, which has fewer components and a simpler structure, thereby reducing the cost of the power supply circuit 100 and thus reducing the cost of the microwave heating device 10.

[0034] In one embodiment, the controllable transistor can be one or more of a transistor, a power transistor, a silicon controlled rectifier diode, and a bidirectional silicon controlled rectifier diode, and is not limited thereto.

[0035] In one embodiment, the power supply circuit 100 further includes a zero-crossing detection circuit 140, which detects the zero-crossing signal of the AC signal. Specifically, the zero-crossing detection circuit 140 includes a first zero-crossing detection circuit (not shown) and a second zero-crossing detection circuit (not shown). The first zero-crossing detection circuit is connected to the input terminal of the positive half-cycle of the AC signal in the rectifier circuit 110 and the control circuit 400, respectively. The first zero-crossing detection circuit detects the zero-crossing signal of the positive half-cycle signal and outputs a positive zero-crossing signal to the control circuit 400. The second zero-crossing detection circuit is connected to the input terminal of the negative half-cycle of the AC signal in the rectifier circuit 110 and the control circuit 400, respectively. The second zero-crossing detection circuit detects the zero-crossing signal of the negative half-cycle signal and outputs an inverted zero-crossing 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.

[0036] In one embodiment, the first zero-crossing detection circuit and the second zero-crossing detection circuit have the same structure. Specifically, the first zero-crossing detection circuit includes a diode D31, resistors R31, R32, R33, and R34, and a switching transistor Q31. The anode of diode D31 is connected to an AC signal. The two ends of resistor R31 are connected to the cathode of diode D31, one end of resistor R32, and one end of resistor R33, respectively. The other end of resistor R32 is grounded (GND). The other end of resistor R33 is connected to the control terminal of switching transistor Q31. The second terminal of switching transistor Q31 is grounded (GND). One end of resistor R34 is connected to a DC power supply signal VCC. The other end of resistor R34 is connected to the first terminal of switching transistor Q31 and the control circuit 400, respectively.

[0037] In one embodiment, the power supply circuit 100 further includes a filter circuit 120, which is connected to the rectifier circuit 110 and the microwave generator circuit 200, respectively.

[0038] In one embodiment, the filter circuit 120 may be an LC filter circuit.

[0039] In one embodiment, the microwave generating circuit 200 includes a resonant capacitor C201, a transformer L201, a voltage multiplier circuit 201, and a magnetron 202. The resonant capacitor C201 is connected in series with the inverter switch Q21 and then in parallel across the filter circuit 120. The primary coil of the transformer L201 is connected in parallel with the resonant capacitor C201. The voltage multiplier circuit 201 is connected to the secondary coil of the transformer L201 and is used to generate the voltage to drive the magnetron 202.

[0040] In other embodiments, the microwave generating circuit 200 may include semiconductor devices, modules, integrated circuits, etc., that generate microwaves, and is not limited thereto.

[0041] In one embodiment, the inverter switch Q21 includes any one of a transistor or a power transistor, which is not limited herein.

[0042] In one embodiment, the control circuit 400 includes a processor (not shown) and peripheral circuitry for maintaining normal operation of the processor. The processor may be an integrated circuit chip with signal processing capabilities. The processor can also be a general-purpose processor, a digital signal processor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices. The general-purpose processor can also be a microprocessor or any conventional processor.

[0043] In one embodiment, a separate second control circuit (not shown in the figure) may be provided in the power supply circuit 100. The second control circuit is electrically connected to the control circuit 400 of the microwave heating device 10. The control circuit 400 controls the operation of the power supply circuit 100 by controlling the operation of the second control circuit.

[0044] In one embodiment, referring to FIG3, which is a circuit diagram of another embodiment of the microwave heating device provided in this application, the inverter switch includes sub-inverter switches Q21, Q22, Q23, and Q24, which are arranged in an H-bridge configuration. When adjusting the heating power of the microwave heating device 10, two sub-inverter switches can be controlled to operate in half-bridge mode, or all four sub-inverter switches can be controlled to operate in full-bridge mode. In half-bridge mode, the bus voltage of the power supply circuit 100 decreases, thereby reducing the heating power of the microwave heating device 10; in full-bridge mode, the bus voltage of the power supply circuit 100 increases, thereby increasing the heating power of the microwave heating device 10. For example, by operating two sub-inverter switches in half-bridge mode and adjusting the conduction time of the rectifier circuit 110, the heating power of the microwave heating device 10 can be further reduced. Furthermore, by further adjusting the control parameters of the sub-inverter switches, such as the drive frequency or duty cycle of the pulse width modulation signal, i.e., by having both sub-inverter switches operate in half-bridge mode, and comprehensively adjusting the drive frequency of the sub-inverter switches, the duty cycle of the pulse width modulation signal, and the conduction duration of the rectifier circuit 110 within the AC signal cycle, the problem of excessive heating power adjustment caused by adjusting only one or two factors, leading to reduced reliability of the corresponding devices, can be mitigated, thereby improving the accuracy of the target heating power adjustment. The adjustment of the sub-inverter switch control parameters can be done by adjusting only the drive frequency, only the duty cycle of the pulse width modulation signal, or both; there are no restrictions on this.

[0045] In one embodiment, continuing to refer to FIG3, the power supply circuit 100 further includes a current transformer U1 and a second rectifier circuit 150. The current transformer U1 is electrically connected to the inverter switch. The second rectifier circuit 150 is electrically connected to the current transformer U1 and the control circuit 400. The current transformer U1 acquires the output electrical signal of the inverter switch, and the second rectifier circuit 150 rectifies the output electrical signal to convert the AC output signal into a DC signal, which is then output to the control circuit 400. In this embodiment, the current transformer U1 and the second rectifier circuit 150 acquire the output signal of the inverter switch to ensure the validity of the inverter switch's output signal, thereby obtaining the effective actual heating power of the microwave heating device 10 and achieving precise adjustment of the target heating power.

[0046] In one embodiment, the control parameters of the inverter switch Q21 may be the driving frequency of the inverter switch Q21, or the duty cycle of the pulse width modulation signal of the inverter switch Q21, or the driving frequency and the duty cycle of the pulse width modulation signal of the inverter switch Q21.

[0047] Among them, because the driving frequency needs to meet the requirements When the drive frequency or duty cycle of the pulse width modulation signal of the inverter switch Q21 is adjusted to a certain level, the inherent frequency limitation of the inverter switch Q21 prevents it from executing the drive frequency or duty cycle of the pulse width modulation signal. Therefore, the heating power of the microwave generating circuit 200 cannot be further increased or decreased. If the user needs to heat at a power lower than the minimum power achievable by the inverter switch Q21, changing the control parameters of the inverter switch Q21 cannot meet the user's needs. To solve the above technical problem, this application proposes a control method for the microwave heating device 10 to meet the user's low-power heating requirements.

[0048] Referring to Figure 4, which is a schematic flowchart of an embodiment of the control method for a microwave heating device provided in this application, the control method includes the following steps:

[0049] Step S100: Obtain the target heating power of the microwave heating device.

[0050] When using the microwave heating device, the user inputs the target heating power. The target heating power can be the heating power input by the user, or it can be the heating power corresponding to the heating mode input by the user; neither is limited here. The target heating power can be a specific value or a range of values; neither is limited here.

[0051] Step S200: In response to the target heating power being less than the preset power, the control parameters of the inverter switch are adjusted to adjust the actual heating power of the microwave heating equipment to the preset power.

[0052] The heating needs of users can be identified through preset power settings. For example, if the target heating power is greater than or equal to the preset power, it is assumed that the user has a high-power heating need; if the target heating power is less than the preset power, it is assumed that the user has a low-power heating need. The preset power can be a fixed power value in the microwave heating device; the microwave heating device can be set with multiple preset power settings, and users can select and set a specific preset power based on their needs or the control circuit based on user habits.

[0053] After obtaining the target heating power, it is compared with the preset power. If the target heating power is detected to be less than the preset power, the control parameters of the inverter switch are adjusted to adjust the actual heating power of the microwave heating equipment to the preset power. The control parameters of the inverter switch include the drive frequency or the duty cycle of the pulse width modulation signal. Adjusting the control parameters of the inverter switch can be done by adjusting only the drive frequency, only the duty cycle of the pulse width modulation signal, or both; there are no restrictions on this.

[0054] In one embodiment, the preset power ranges from 500W to 1000W. Existing microwave heating equipment mainly focuses on high-power heating, with a minimum heating power as low as 500W. The specific value of the preset power can be set according to the minimum heating power achievable by the inverter switch; for example, the preset power can be 500W, 600W, 650W, 800W, 1000W, etc.

[0055] Step S300: In response to the actual heating power reaching the preset power, the conduction time of the rectifier circuit during the AC signal cycle is reduced to reduce the actual heating power to the target heating power.

[0056] After adjusting the actual heating power to the preset power using an inverter switch, due to hardware limitations of the inverter switch, it may be unable to execute the changed control parameters, or the difference between the preset power and the target heating power may be too small, making it impossible to achieve precise adjustment from the preset power to the target heating power when changing the inverter switch's control parameters. To avoid these situations, this embodiment reduces the conduction time of the rectifier circuit during the AC signal cycle, thereby reducing the output voltage of the power supply circuit, and further reducing the actual heating power of the microwave heating device to the target heating power.

[0057] The control method for the microwave heating equipment of this application obtains the target heating power required by the user. When the target heating power is less than the preset power, it first performs a primary adjustment by adjusting the control parameters of the inverter switch to adjust the actual heating power of the microwave heating equipment to the preset power. After the actual heating power is adjusted to the preset power, a secondary adjustment is performed by reducing the conduction time of the rectifier circuit within the AC signal cycle to further adjust the actual heating power to the target heating power. In other words, the control method of this application can achieve two-stage power regulation of the microwave heating equipment, and can further reduce the actual heating power by reducing the conduction time of the rectifier circuit within the AC signal cycle. The lower limit of the actual heating power is not constrained by the lower limit of the control parameters of the inverter switch under normal operating conditions, thus meeting the user's low-power heating needs. Furthermore, the control method of this application, by combining multiple parameters such as the control parameters of the inverter switch (e.g., the drive frequency of the inverter switch, the duty cycle of the pulse width modulation signal), and the conduction time of the rectifier circuit, comprehensively adjusts the heating power of the microwave heating equipment, enabling precise adjustment of the microwave heating equipment.

[0058] In one embodiment, the control method further includes:

[0059] Step S400: In response to the target heating power being greater than or equal to the preset power, the control parameters of the inverter switch are adjusted to adjust the actual heating power of the microwave heating equipment to the target heating power.

[0060] When the target heating power is greater than or equal to the preset power, the control parameters of the inverter switch are adjusted to adjust the actual heating power of the microwave heating equipment to the target heating power. The control parameters of the inverter switch include the drive frequency of the inverter switch or the duty cycle of the pulse width modulation signal. Adjusting the control parameters of the inverter switch can be done by adjusting only the drive frequency, only the duty cycle of the pulse width modulation signal, or both the drive frequency and the duty cycle of the pulse width modulation signal; there are no restrictions on this.

[0061] In this embodiment, when the target heating power is greater than or equal to the preset power, the control parameters of the inverter switch are directly adjusted to adjust the actual heating power to the target heating power by increasing the bus voltage of the power supply circuit, thereby meeting the user's high-power heating needs for microwave heating equipment.

[0062] In one embodiment, referring to FIG5, FIG5 is a flowchart illustrating an embodiment of step S400 of the embodiment of FIG4. Step S400 includes:

[0063] Step S410: Adjust the drive frequency of the inverter switch.

[0064] Step S420: Adjust the duty cycle of the pulse width modulation signal of the inverter switch.

[0065] Step S430: Determine whether the actual heating power is equal to the target heating power. If not, return to the steps after step S410. If yes, end the power adjustment process of the microwave heating device and heat at the target heating power.

[0066] This embodiment can increase the bus voltage of the power supply circuit by adjusting the drive frequency of the inverter switch and the duty cycle of the pulse width modulation signal, thereby improving the high-power regulation of the microwave heating equipment. At the same time, by adjusting the drive frequency of the inverter switch and the duty cycle of the pulse width modulation signal, the heating power of the microwave heating equipment can be precisely adjusted.

[0067] In some embodiments, only the drive frequency of the inverter switch or the duty cycle of the pulse width modulation signal of the inverter switch can be adjusted; the order of drive frequency adjustment and duty cycle adjustment is not limited; the specific magnitude 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.

[0068] In one embodiment, the rectifier circuit includes a rectifier bridge, at least one arm of the rectifier bridge is provided with a controllable transistor, the control terminal of the controllable transistor is connected to a control circuit, and the control method further includes the following steps:

[0069] Step S500: Perform zero-crossing detection on the AC signal input to the rectifier bridge to determine the positive and negative half-cycles of the AC signal.

[0070] In order to achieve precise control over the conduction time of the inverter switch and rectifier circuit, zero-crossing detection is performed on the AC signal to determine the positive and negative half-cycles of the AC signal.

[0071] It is worth noting that step S500 can be performed before adjusting the control parameters of the inverter switch or before reducing the conduction time of the rectifier circuit during the AC signal cycle, and there is no limitation on this.

[0072] Reducing the conduction time of the rectifier circuit during the AC signal cycle includes:

[0073] S310: Shorten the conduction time of the upper arm of the rectifier bridge during the positive half-cycle or shorten the conduction time of the lower arm of the rectifier bridge during the negative half-cycle.

[0074] The upper and lower arms of the rectifier bridge operate during the positive and negative half-cycles of the AC signal, respectively. Therefore, reducing the conduction time of the rectifier circuit within the AC signal cycle can shorten the conduction time of the upper arm, or the lower arm, or both. When shortening the conduction time of the upper and lower arms, their respective conduction times can be the same or different; this is not limited here.

[0075] This embodiment shortens the conduction time of the rectifier circuit by reducing the conduction time of the upper or lower bridge arm of the rectifier bridge, which can meet the low-power heating requirements of microwave heating equipment. Moreover, this method requires little modification to the circuit structure of the microwave heating equipment and is easy to implement.

[0076] For example, if the AC signal period is S, and the conduction time of the rectifier bridge within the AC signal period is T, if the conduction time T is less than or equal to 1 / 2 S, only the conduction time T1 of the upper bridge arm can be controlled, in which case T1 = T; or only the conduction time T2 of the lower bridge arm can be controlled, in which case T2 = T; or the conduction time T1 of the upper bridge arm and the conduction time T2 of the lower bridge arm can be controlled, in which case T1 + T2 = T. Here, T1 and T2 can be equal or unequal, which is not restricted here. If T is greater than 1 / 2 S and less than S, the conduction time T1 of the upper bridge arm and the conduction time T2 of the lower bridge arm can be controlled, in which case T1 + T2 = T. Here, T1 and T2 can be equal or unequal, which is not restricted here.

[0077] In one embodiment, the conduction duration of the upper bridge arm is the same as that of the lower bridge arm, which can balance the switching losses of the controllable transistors corresponding to the upper and lower bridge arms. For example, the upper and lower bridge arms are equipped with controllable transistors such as transistors, power transistors, or thyristors. When shortening the conduction duration of the rectifier circuit, the conduction duration of the controllable transistors in the upper and lower bridge arms is controlled to be the same, so that the number of turn-on and turn-off times of the controllable transistors is the same, which can balance the switching losses of the controllable transistors corresponding to the upper and lower bridge arms.

[0078] In one embodiment, the conduction time of the upper bridge arm is symmetrical about the midpoint of the time point corresponding to the peak of the AC signal in the positive half-cycle. The conduction time of the lower bridge arm is symmetrical about the midpoint of the time point corresponding to the trough of the AC signal in the negative half-cycle. Referring to Figure 6, which is a signal timing diagram provided in this application, it can be understood that in the positive half-cycle of the AC signal, the conduction interval of the upper bridge arm corresponds to the interval symmetrical about the midpoint of the time point corresponding to the peak of the positive half-cycle. In the negative half-cycle of the AC signal, the conduction interval of the lower bridge arm corresponds to the interval symmetrical about the midpoint of the time point corresponding to the trough of the negative half-cycle. This embodiment selects the conduction interval of the bridge arm to correspond to the midpoint of the time point corresponding to the peak or trough of the AC signal, which facilitates the adjustment of the bridge arm.

[0079] In one embodiment, referring to FIG7, FIG7 is a schematic flowchart of another embodiment of the control method for the microwave heating device provided in this application. The control method further includes:

[0080] Step S600: Obtain initial power.

[0081] The initial power can be the default heating power when the microwave heating device is powered on; alternatively, it can be the previous target heating power when the user switches to a different target heating power. For example, when the microwave heating device is powered on and its initial power is obtained, the default heating power is used as the initial power. If the microwave heating device obtains a new target heating power while powered on, the previous target heating power is used as the initial power. Alternatively, if the microwave heating device obtains a new target heating power during the heating process, the actual heating power is used as the initial power.

[0082] Step S700: Determine whether the initial power is greater than or equal to the preset power.

[0083] The initial power is compared with the preset power. If the initial power is greater than or equal to the preset power, then the following steps are executed: if the target heating power is less than the preset power, the control parameters of the inverter switch are adjusted to adjust the actual heating power of the microwave heating device to the preset power; and if the actual heating power reaches the preset power, the conduction time of the rectifier circuit within the AC signal cycle is reduced to decrease the actual heating power to the target heating power. It can be understood that since the target heating power is less than the preset power, if the initial power is greater than or equal to the preset power, the steps after step S200 are executed to adjust the initial power to the target heating power. That is, when the initial power is greater than or equal to the preset power, the control parameters of the inverter switch are adjusted to reduce the actual heating power to adjust the actual heating power of the microwave heating device to the preset power, and when the actual heating power reaches the preset power, the conduction time of the rectifier circuit within the AC signal cycle is reduced to decrease the actual heating power to the target heating power.

[0084] If the initial power is less than the preset power, step S300 is executed, which involves adjusting the conduction duration of the rectifier circuit during the AC signal cycle to reduce the actual heating power to the target heating power. It is understood that since the target heating power is less than the preset power, adjusting the control parameters of the inverter switch may not reduce the actual heating power, or the adjustment range may be too large to achieve the target heating power. Therefore, when the initial power is less than the preset power, the conduction duration of the rectifier circuit during the AC signal cycle is directly adjusted to reduce the actual heating power to the target heating power, thus meeting the user's low-power heating needs while improving the adjustment efficiency of the microwave heating equipment.

[0085] In one embodiment, referring to FIG8, FIG8 is a flowchart of an embodiment of step S300 of FIG4. Step S300: In response to the actual heating power reaching the preset power, the conduction time of the rectifier circuit in the AC signal cycle is reduced to reduce the actual heating power to the target heating power, including the following steps:

[0086] Step S310: Reduce the conduction time of the rectifier circuit during the AC signal cycle.

[0087] Step S320: Adjust the control parameters of the inverter switch, such as adjusting the drive frequency of the inverter switch, or adjusting the duty cycle of the pulse width modulation signal of the inverter switch, or simultaneously adjusting the drive frequency of the inverter switch and the duty cycle of the pulse width modulation signal.

[0088] Step S330: Determine whether the actual heating power is equal to the target heating power. If yes, stop power adjustment and heat the food with the current actual heating power. If no, return to step S310.

[0089] In this embodiment, after reducing the conduction time of the rectifier circuit within the AC signal cycle, if the actual heating power does not decrease to the target heating power, the control parameters of the inverter switch are further adjusted to further reduce the actual heating power to the target heating power. Since the target heating power is related to the control parameters of the inverter switch, such as the drive frequency or the duty cycle of the pulse width modulation signal, as well as the conduction time of the rectifier circuit within the AC signal cycle, by comprehensively adjusting the drive frequency, the duty cycle of the pulse width modulation signal, and the conduction time of the rectifier circuit within the AC signal cycle, the problem of excessive heating power adjustment due to adjusting only one or two factors, which leads to reduced reliability of the corresponding devices, can be improved, thereby improving the accuracy of the target heating power adjustment.

[0090] In one embodiment, the power supply circuit further includes a current transformer electrically connected to the inverter switch and a second rectifier circuit electrically connected to the circuit transformer. The control method further includes:

[0091] Step S101: Obtain the output electrical signal of the inverter switch through the current transformer.

[0092] When a microwave heating device operates at a target heating power of less than 500W, if the current signal is detected using resistance detection, there may be situations where the current cannot be detected. Therefore, this embodiment obtains the output electrical signal of the inverter switch through a current transformer.

[0093] Step S102: Rectify the output electrical signal through the second rectifier circuit.

[0094] The output electrical signal is rectified by a second rectifier circuit to convert the AC output electrical signal into a DC signal.

[0095] Step S103: Determine the actual heating power based on the rectified output electrical signal, and determine whether the actual heating power has dropped to the target heating power.

[0096] If the actual heating power exceeds the target heating power, the steps of adjusting the control parameters of the inverter switch and adjusting the conduction time of the rectifier circuit during the AC signal cycle are executed until the actual heating power decreases to the target heating power. That is, if the actual heating power exceeds the target heating power, the steps following step S200 are executed.

[0097] This embodiment obtains the output signal of the inverter switch through a current transformer and a second rectifier circuit to ensure the validity of the inverter switch's output signal, thereby obtaining the actual heating power of the microwave heating equipment and achieving precise adjustment of the target heating power.

[0098] It is worth noting that steps S101-S103 can be performed when the actual heating power of the microwave heating device is obtained.

[0099] This application provides a computer storage medium. Referring to FIG9, FIG9 is a schematic diagram of the structure of an embodiment of the computer storage medium provided in this application. The computer storage medium 20 stores computer program instructions 21. The computer program instructions 21 can be executed by a processor to perform a control method for a microwave heating device. The control method for the microwave heating device is any one of the control methods for the microwave heating device described above, and will not be elaborated here.

[0100] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A control method for a microwave heating device, characterized in that, The microwave heating device is equipped with a power supply circuit, which includes a rectifier circuit and an inverter switch. The control method includes: Obtain the target heating power of the microwave heating device; In response to the target heating power being less than the preset power, the control parameters of the inverter switch are adjusted to adjust the actual heating power of the microwave heating device to the preset power. In response to the actual heating power reaching the preset power, the conduction time of the rectifier circuit during the AC signal cycle is reduced to decrease the actual heating power to the target heating power.

2. The control method according to claim 1, characterized in that, The rectifier circuit includes a rectifier bridge, and the control method further includes: Zero-crossing detection is performed on the AC signal input to the rectifier bridge to determine the positive and negative half-cycles of the AC signal; Reducing the on-time of the rectifier circuit during the AC signal cycle includes: The conduction time of the upper arm of the rectifier bridge during the positive half-cycle or the conduction time of the lower arm of the rectifier bridge during the negative half-cycle is shortened.

3. The control method according to claim 2, characterized in that, The conduction time of the upper bridge arm is symmetrical with respect to the time point corresponding to the peak of the AC signal in the positive half-cycle as the midpoint; the conduction time of the lower bridge arm is symmetrical with respect to the time point corresponding to the trough of the AC signal in the negative half-cycle as the midpoint.

4. The control method according to claim 2, characterized in that, The conduction duration of the upper bridge arm is the same as that of the lower bridge arm.

5. The control method according to claim 1, characterized in that, The step of reducing the conduction time of the rectifier circuit during the AC signal cycle in response to the actual heating power reaching the preset power, to reduce the actual heating power to the target heating power, includes: In response to the actual heating power reaching the preset power, the conduction time of the rectifier circuit during the AC signal cycle is reduced, and the control parameters of the inverter switch are adjusted to reduce the actual heating power to the target heating power.

6. The control method according to claim 1, characterized in that, The control method further includes: In response to the target heating power being greater than or equal to the preset power, the control parameters of the inverter switch are adjusted to adjust the actual heating power of the microwave heating device to the target heating power; The control parameters include the drive frequency of the inverter switch or the duty cycle of the pulse width modulation signal.

7. The control method according to claim 1, characterized in that, The control method further includes: Obtain initial power; In response to the initial power being greater than or equal to the preset power, the following steps are performed: in response to the target heating power being less than the preset power, the control parameters of the inverter switch are adjusted to adjust the actual heating power of the microwave heating device to the preset power; and in response to the actual heating power reaching the preset power, the conduction time of the rectifier circuit in the AC signal cycle is reduced to decrease the actual heating power to the target heating power. In response to the initial power being less than the preset power, the conduction duration of the rectifier circuit during the AC signal cycle is adjusted to reduce the actual heating power to the target heating power.

8. The control method according to claim 1, characterized in that, The preset power range is 500W-1000W.

9. A power supply circuit, characterized in that, A microwave heating device, the microwave heating device including a control circuit and a power supply circuit electrically connected to the control circuit, the power supply circuit including: The rectifier circuit has at least one bridge arm equipped with a controllable transistor, which is used to turn on the corresponding bridge arm; An inverter switch is electrically connected to the rectifier circuit and the microwave generating circuit of the microwave heating device. The controllable transistor and the inverter switch are electrically connected to the control circuit so that the control circuit controls the operation of the rectifier circuit and the inverter switch using the control method described in any one of claims 1 to 8, thereby controlling the heating power of the microwave generating circuit.

10. A microwave heating device, characterized in that, include: The power supply circuit, control circuit, and microwave generating circuit of claim 9, wherein the microwave generating circuit is electrically connected to the inverter switch, and the control circuit uses the control method of any one of claims 1 to 8 to control the operation of the rectifier circuit and the inverter switch to control the heating power of the microwave generating circuit.

11. A computer storage medium, characterized in that, The computer storage medium stores computer program instructions that can be executed by a processor to perform the control method according to any one of claims 1-8.

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