Microwave heating equipment, control method thereof, power supply circuit and computer storage medium

Abstract

The invention provides a control method of microwave heating equipment, a power supply circuit for the microwave heating equipment, a microwave oven and a computer storage medium. The microwave heating equipment is provided with a power supply circuit, the power supply circuit comprises a first rectifying circuit and an inverter circuit, and the control method comprises the steps of obtaining target heating power of the microwave heating equipment; and in response to the condition that the target heating power is smaller than the preset power, controlling the inverter circuit to work in a half-bridge mode, and adjusting the conduction duration of the first rectifying circuit in the alternating current signal period so as to reduce the actual heating power to the target heating power. According to the control method of the microwave heating equipment provided by the invention, low-power heating of the microwave heating equipment can be realized.

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] In order to solve the above technical problems, the present application provides a control method for a microwave heating device, the microwave heating device is provided with a power supply circuit, the power supply circuit includes a first rectifier circuit and an inverter circuit, the control method includes obtaining a target heating power of the microwave heating device; in response to the target heating power being less than a preset power, the inverter circuit is controlled to operate in a half-bridge mode, and the conduction time of the first rectifier circuit within the AC signal cycle is adjusted to reduce the actual heating power to the target heating power.

[0005] In one embodiment, the inverter circuit is controlled to operate in half-bridge mode, and the conduction time of the first rectifier circuit within the AC signal cycle is adjusted, including controlling the inverter circuit to operate in half-bridge mode; in half-bridge mode, 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; adjusting the conduction time of the first rectifier circuit within the AC signal cycle to reduce the actual heating power to the target heating power.

[0006] In one embodiment, the power supply circuit also includes a current transformer electrically connected to the inverter circuit and a second rectifier circuit electrically connected to the circuit transformer, and the control method also includes obtaining an output electrical signal of the inverter circuit through the current transformer; rectifying the output electrical signal through the second rectifier circuit; determining whether the actual heating power drops to the target heating power based on the rectified output electrical signal; in response to the actual heating power being greater than the target heating power, executing the steps of adjusting the control parameters of the inverter circuit and adjusting the conduction time of the first rectifier circuit within the AC signal cycle until the actual heating power drops to the target heating power.

[0007] In one embodiment, the control method also includes controlling the inverter circuit to operate in full-bridge mode in response to the target heating power being greater than or equal to a preset power; in the full-bridge mode, 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.

[0008] In one embodiment, the first rectifier circuit includes a rectifier bridge, and the control method also includes performing zero-crossing detection on the AC signal input to the rectifier bridge to determine the positive half-cycle and negative half-cycle of the AC signal; adjusting the conduction time of the first rectifier circuit during the AC signal cycle, including shortening the conduction time of the upper arm of the rectifier bridge in the positive half-cycle or shortening the conduction time of the lower arm of the rectifier bridge in the negative half-cycle.

[0009] In one embodiment, the conduction time of the upper bridge arm 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 lower bridge arm is symmetrical with the time point corresponding to the trough of the AC signal in the negative half cycle as the midpoint.

[0010] In one embodiment, the conduction time length of the upper bridge arm is the same as the conduction time length of the lower bridge arm.

[0011] 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 comprising a control circuit and a power supply circuit electrically connected to the control circuit, the power supply circuit comprising a first rectifier circuit, an inverter circuit and a control circuit, at least one bridge arm of the first rectifier circuit is provided with a controllable tube, the controllable tube is used to turn on the corresponding bridge arm; the inverter circuit is electrically connected to the first rectifier circuit and the microwave generating circuit of the microwave heating device; the control circuit is connected to the controllable tube and the inverter circuit, and the above control method is used to control the operation of the first rectifier circuit and the inverter circuit.

[0012] In one embodiment, the power supply circuit further includes a current transformer and a second rectifier circuit, the current transformer is connected to the inverter circuit; the second rectifier circuit is connected to the current transformer and the control circuit.

[0013] 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 inverter circuit, and the control circuit adopts the above-mentioned control method to control the operation of the first rectifier circuit and the inverter circuit to control the heating power of the microwave generating circuit.

[0014] 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.

[0015] 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 controls the inverter circuit to work in the half-bridge mode to perform the first-level power regulation, and then adjusts the conduction time of the first rectifier circuit in the AC signal cycle to perform the second-level power regulation, and further reduces 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 first rectifier circuit in the AC signal cycle, 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 inverter circuit and the first rectifier circuit in the AC cycle 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] 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:

[0017] Figure 1 It is a structural schematic diagram of an embodiment of a microwave heating device provided by the present application;

[0018] Figure 2 is a circuit diagram of an embodiment of a microwave heating device provided by the present application;

[0019] Figure 3 It is a flow chart of an embodiment of a control method for a microwave heating device provided by the present application;

[0020] Figure 4 yes Figure 3 Implementation step S300 is a flow chart of an implementation example;

[0021] Figure 5 It is a signal timing diagram provided by this application;

[0022] Figure 6 yes Figure 3 Implementation step S200 is a flow chart of an implementation example;

[0023] Figure 7 It is a structural diagram of an embodiment of a computer storage medium provided by the present application. DETAILED DESCRIPTION

[0024] 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.

[0025] 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.

[0026] 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.

[0027] The present application provides a microwave heating device, referring to Figure 1 , Figure 1 It is a structural schematic diagram of an embodiment of a microwave heating device provided in the present application. The microwave heating device 10 includes a main 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 on the main body 300.

[0028] The control circuit 400 controls the heating power of the microwave generating circuit 200 by controlling the power supply circuit 100 to operate, thereby controlling the heating power of the microwave heating device 10 .

[0029] 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.

[0030] 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 first rectifier circuit 110 and an inverter circuit 120. The first rectifier circuit 110 is connected to an AC signal, and at least one bridge arm of the first rectifier circuit 110 is provided with a controllable tube, and the control end of the controllable tube is electrically connected to the control circuit 400, and the controllable tube is used to conduct the corresponding bridge arm. The inverter circuit 120 is electrically connected to the first rectifier circuit 110 and the microwave generating circuit 200. The controllable tube and the inverter circuit 120 are also connected to the control circuit 400, and the control circuit 400 controls the controllable tube and the inverter circuit 120 to work, so as to control the microwave generating circuit 200 to generate microwaves. The heating power of the microwave heating device 10 can be adjusted by adjusting the conduction time of the controllable tube and the control parameters of the inverter circuit 120.

[0031] In one embodiment, continue to refer to Figure 2 , the first rectifier circuit 110 includes a rectifier bridge composed of a diode D11, a diode D12, a controllable tube T11 and a controllable tube T12, wherein the diode D12 and the controllable tube T11 constitute a bridge arm, and the diode D11 and the controllable tube T12 constitute another bridge arm. In other embodiments, the diode D11 and the diode D12 constitute one bridge arm of the rectifier bridge, and the controllable tube T11 and the controllable tube T12 constitute another bridge arm of the rectifier bridge. In other embodiments, the first rectifier circuit 110 may also include a rectifier bridge composed of three diodes and one controllable tube, or a rectifier bridge composed of four controllable tubes, or the rectifier bridge may include four diodes and at least one controllable tube, and the controllable tube may be set in any one bridge arm to turn on or off the corresponding bridge arm, which is not limited here. The control circuit 400 can adjust the turn-on time of the first rectifier circuit 110 by adjusting the turn-on time of the controllable tube.

[0032] In other embodiments, the first rectifier circuit 110 may further include a bidirectional conductive controllable transistor (marked in the figure), which can realize the rectification function of the rectifier full bridge. The first rectifier circuit 110 of this embodiment includes only one bidirectional conductive controllable transistor, which has few components and a simple structure, and can reduce the cost of the power supply circuit 100, thereby reducing the cost of the microwave heating device 10.

[0033] In one embodiment, the controllable transistor may be one or more of a triode, a power tube, a thyristor diode, and a bidirectional thyristor diode, which is not limited here.

[0034] In one embodiment, the power supply circuit 100 also includes a zero-crossing detection circuit 150, and the zero-crossing detection circuit 150 is used to detect the zero-crossing signal of the AC signal. Specifically, the zero-crossing detection circuit 150 includes a first zero-crossing detection circuit (not labeled in the figure) and a second zero-crossing detection circuit (not labeled in the figure). Wherein, the first zero-crossing detection circuit is respectively connected to the access end of the positive half-cycle in the AC signal of the first 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 first 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.

[0035] 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, a resistor R31, a resistor R32, a resistor R33, a resistor R34 and a switch tube Q31, the anode of the diode D31 is connected to the AC signal, the two ends of the resistor R31 are respectively connected to the cathode of the diode D31, one end of the resistor R32 and one end of the resistor R33, the other end of the resistor R32 is grounded GND, the other end of the resistor R33 is connected to the control end of the switch tube Q31, the second end of the switch tube Q31 is grounded GND, one end of the resistor R34 is connected to the DC power supply signal VCC, and the other end of the resistor R34 is respectively connected to the first end of the switch tube Q31 and the control circuit 400.

[0036] In one embodiment, continue to refer to Figure 2 , the power supply circuit also includes a current transformer U1 and a second rectifier circuit 140. The current transformer U1 is electrically connected to the inverter circuit 120. The second rectifier circuit 140 is electrically connected to the current transformer U1 and the control circuit 400. The current transformer U1 obtains the output electrical signal of the inverter circuit 120, and the second rectifier circuit 140 rectifies the output electrical signal to convert the AC output electrical signal into a DC signal, and outputs it to the control circuit 400. In this embodiment, the output signal of the inverter circuit 120 is obtained by the current transformer U1 and the second rectifier circuit 140 to ensure the validity of the output signal of the inverter circuit 120, thereby obtaining the actual heating power of the effective microwave heating device and realizing the precise adjustment of the target heating power.

[0037] In one embodiment, the second rectifier circuit 140 includes a rectifier bridge composed of four diodes, wherein the diode D41 and the diode D43 constitute one arm of the rectifier bridge, and the diode D42 and the diode D44 constitute the other arm of the rectifier bridge.

[0038] In one embodiment, the inverter circuit 120 includes four inverter switches forming an H bridge, wherein the inverter switch Q21 and the inverter switch Q23 form one bridge arm of the inverter circuit 120, and the inverter switch Q22 and the inverter switch Q24 form another bridge arm of the inverter circuit 120. The microwave generating circuit 200 is connected between the two bridge arms. When the inverter circuit 120 operates in a half-bridge mode, the inverter switch Q21 and the inverter switch Q23 form a half-bridge and are in a working state, the inverter switch Q24 is in a conducting state, and the inverter switch Q22 is in a cut-off state; or, the inverter switch Q22 and the inverter switch Q24 form a half-bridge and are in a working state, the inverter switch Q23 is in a conducting state, and the inverter switch Q21 is in a cut-off state. When the inverter circuit operates in the full-bridge state, when the inverter switch Q21 and the inverter switch Q24 are in the on state, the inverter switch Q22 and the inverter switch Q23 are in the off state; when the inverter switch Q21 and the inverter switch Q24 are in the off state, the inverter switch Q22 and the inverter switch Q23 are in the on state.

[0039] In one embodiment, continue to refer to Figure 2 The microwave generating circuit 200 includes a resonant capacitor C201, a transformer L201, a voltage doubling circuit 201 and a magnetron 202. The resonant capacitor C201 is connected in series with the primary coil of the transformer L201 and then connected in series to the middle node of the two bridge arms of the inverter circuit 120. The voltage doubling circuit 201 is connected to the secondary coil of the transformer L201 to generate a voltage to drive the magnetron 202.

[0040] 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.

[0041] In one embodiment, the inverter switch of the inverter circuit 120 includes any one of a triode and a power tube, which is not limited here.

[0042] 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.

[0043] 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.

[0044] In one embodiment, the control parameter of the inverter circuit 120 may be the driving frequency of the inverter switch, or the duty cycle of the pulse width modulation signal of the inverter switch, or the driving frequency of the inverter switch Q21 and the duty cycle of the pulse width modulation signal.

[0045] Among them, because the driving frequency of the inverter switch needs to meet When the driving frequency of the inverter switch in the inverter circuit 120 or the duty cycle of the pulse width modulation signal is adjusted to a certain degree, the limitation of the inherent frequency of the inverter switch causes the inverter switch 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 inverter switch can achieve, the user's low-power heating demand cannot be met by changing the control parameters of the inverter switch. 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 demand.

[0046] 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:

[0047] Step S100: obtaining the target heating power of the microwave heating device.

[0048] 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.

[0049] Step S200: In response to the target heating power being less than the preset power, the inverter circuit is controlled to operate in a half-bridge mode, and the conduction time of the first rectifier circuit in the AC signal cycle is adjusted to reduce the actual heating power to the target heating power.

[0050] 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.

[0051] After obtaining the target heating power, the target heating power is compared with the preset power. When it is detected that the target heating power is less than the preset power, the inverter circuit is controlled to operate in the half-bridge mode, at which time the output voltage of the inverter circuit is less than the voltage output by the first rectifier circuit, which can reduce the bus voltage of the power supply circuit, thereby reducing the actual heating power of the microwave heating device; in addition, the conduction time of the first rectifier circuit within the AC signal cycle is further adjusted to adjust the actual heating power by adjusting the conduction time of the power supply circuit, thereby further reducing the actual heating power of the microwave heating device to the target heating power.

[0052] 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 controls the inverter circuit to work in the half-bridge mode to perform the first-level power regulation, and then adjusts the conduction time of the first rectifier circuit in the AC signal cycle to perform the second-level power regulation, and further reduces 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 first rectifier circuit in the AC signal cycle, 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 inverter circuit and the first rectifier circuit in the AC cycle 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.

[0053] 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 500 W. The specific value of the preset power can be set according to the minimum heating power that can be achieved by the inverter circuit. For example, the preset power can be 500W, 600W, 650W, 800W, 1000W, etc.

[0054] In one embodiment, the control method further includes:

[0055] Step S300: In response to the target heating power being greater than or equal to the preset power, the inverter circuit is controlled to operate in full-bridge mode. In the full-bridge mode, the control parameters of the inverter circuit are adjusted to adjust the actual heating power to the target heating power.

[0056] When the inverter circuit works in the full-bridge mode, the output voltage of the inverter circuit is greater than or equal to the output voltage of the first rectifier circuit by adjusting the control parameters of the inverter circuit, thereby adjusting the actual heating power to the target heating power and realizing the high-power heating requirement of the microwave heating device. The control parameters include the driving frequency of the inverter circuit, or the duty cycle of the pulse width modulation signal, or the driving frequency and the duty cycle of the pulse width modulation signal.

[0057] In this embodiment, when the target heating power is greater than or equal to the preset power, the inverter circuit is controlled to operate in the full-bridge mode, and the control parameters of the inverter circuit are adjusted to increase the bus voltage of the power supply circuit, thereby increasing the actual heating power of the microwave heating device and satisfying the user's high-power heating needs. In addition, when the user needs high-power heating, the inverter circuit is directly controlled to operate in the full-bridge mode, which can improve the regulation efficiency of the microwave heating device.

[0058] In one embodiment, when the inverter circuit operates in the full-bridge mode, in order to achieve accurate regulation of the target heating power, the conduction time of the first rectifier circuit in the AC cycle can also be adjusted. This embodiment can adjust the driving frequency of the inverter circuit, the duty cycle of the pulse width modulation signal, and the conduction time of the first rectifier circuit in the AC cycle to achieve 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 or two factors, thereby reducing the reliability of the corresponding device, and thus can improve the regulation accuracy of the target heating power.

[0059] In other embodiments, in order to reduce the loss of the controllable transistor of the first rectifier circuit, when the inverter circuit operates in the full-bridge mode, only the control parameters of the inverter circuit are adjusted.

[0060] In one embodiment, see Figure 4 , Figure 4 yes Figure 3 Embodiment Step S300 is a flow chart of an embodiment, wherein step S300 includes:

[0061] Step S310: Control the inverter circuit to operate in full-bridge mode.

[0062] Step S320: adjusting the driving frequency of the inverter circuit or the duty cycle of the pulse width modulation signal to increase the bus voltage of the power supply circuit. For example, adjusting the driving frequency of the inverter switch in the inverter circuit, or adjusting the duty cycle of the pulse width modulation signal of the inverter switch in the inverter circuit, or adjusting both the driving frequency of the inverter switch in the inverter circuit and the duty cycle of the pulse width modulation signal.

[0063] The order of driving frequency adjustment and duty cycle adjustment is not limited; the specific amplitude and number of control parameter adjustments can be determined based on factors such as target heating power, actual heating power, and software and hardware performance of the microwave heating equipment.

[0064] Step S330: determine whether the actual heating power is equal to the target heating power, if not, return to the steps after step S320. If yes, end the power adjustment process of the microwave heating device, and perform heating at the target heating power.

[0065] After the inverter circuit is controlled to work in the full-bridge mode, the control parameters of the inverter switch in the inverter circuit are further adjusted to further increase 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 driving frequency or the duty cycle of the pulse width modulation signal, the problem of excessive heating power adjustment due to adjusting only one factor, thereby reducing the reliability of the corresponding device, can be improved by comprehensively adjusting the driving frequency and the duty cycle of the pulse width modulation signal, thereby improving the adjustment accuracy of the target heating power.

[0066] In one embodiment, the first rectifier circuit includes a rectifier bridge, at least one bridge arm of the rectifier bridge is provided with a controllable tube, and the control end of the controllable tube is connected to the control circuit, and the control method further includes the following steps:

[0067] Step S400: Perform zero-crossing detection on the AC signal input to the rectifier bridge to determine the positive half cycle and the negative half cycle of the AC signal.

[0068] In order to achieve half-bridge mode control of the inverter circuit, full-bridge mode control of the inverter circuit and accurate control of the conduction time of the first rectifier circuit, zero-crossing detection is performed on the AC signal to determine the positive half cycle and negative half cycle of the AC signal.

[0069] It is worth noting that step S400 may be performed before controlling the inverter circuit to operate, or before reducing the conduction time of the first rectifier circuit in the AC signal cycle, which is not limited here.

[0070] Wherein, adjusting the conduction time of the first rectifier circuit within the AC signal cycle includes:

[0071] Step S210: shortening the conduction time of the upper bridge arm of the rectifier bridge in the positive half cycle or shortening the conduction time of the lower bridge arm of the rectifier bridge in the negative half cycle.

[0072] The upper bridge arm and the lower bridge arm of the rectifier bridge work in the positive half cycle and the negative half cycle of the AC signal respectively. Therefore, reducing the conduction time of the rectifier circuit in the AC signal cycle can shorten the conduction time of the upper bridge arm of the rectifier bridge, or shorten the conduction time of the lower bridge arm of the rectifier bridge, or shorten the conduction time of both the upper bridge arm and the lower bridge arm. When shortening the conduction time of the upper bridge arm and the lower bridge arm, the conduction time of the two can be the same or different, which is not limited here.

[0073] This embodiment shortens the conduction time of the first rectifier circuit by shortening the conduction time of the upper arm or the lower arm of the rectifier bridge, thereby meeting the low-power heating requirements of the microwave heating device. This method makes little change to the circuit structure of the microwave heating device and is easy to implement.

[0074] For example, the AC signal cycle is S, and the conduction time of the rectifier bridge 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 upper bridge arm T1 can be controlled, and T1=T at this time; or only the conduction time of the lower bridge arm T2 can be controlled, and T2=T at this time; or the conduction time of the upper bridge arm T1 can be controlled, and the conduction time of the lower bridge arm T2 can be controlled, and T1+T2=T at this time, wherein T1 and T2 can be equal or unequal, and there is no restriction here. If T is greater than 1 / 2S and T is less than S, the conduction time of the upper bridge arm T1 can be controlled, and the conduction time of the lower bridge arm T2 can be controlled, and T1+T2=T at this time, wherein T1 and T2 can be equal or unequal, and there is no restriction here.

[0075] In one embodiment, the conduction time of the upper bridge arm is the same as the conduction time of the lower bridge arm, which can balance the losses of the controllable tubes corresponding to the upper and lower bridge arms. For example, the upper and lower bridge arms are provided with controllable tubes such as triodes, power tubes or thyristors. When shortening the conduction time of the rectifier circuit, the conduction time of the controllable tubes of the upper bridge arm and the lower bridge arm is controlled to be the same, so that the number of times the controllable tubes are turned on and off is the same, which can balance the losses of the controllable tubes corresponding to the upper and lower bridge arms.

[0076] In one embodiment, the conduction time of the upper bridge arm 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 lower bridge arm 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 It 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 upper bridge arm corresponds to the time point corresponding to the peak of the positive half-cycle, which is a mid-point symmetrical interval. In the negative half-cycle of the AC signal, the conduction interval of the lower bridge arm corresponds to the time point corresponding to the trough of the negative half-cycle, which is a mid-point symmetrical interval. In this embodiment, the conduction interval of the bridge arm is selected to correspond to the time point corresponding to the peak or trough of the AC signal as a mid-point symmetrical interval, which is convenient for adjusting the bridge arm.

[0077] In one embodiment, see Figure 6 , Figure 6 yes Figure 3 Embodiment Step S200 A flow chart of an embodiment, step S200: controlling the inverter circuit to operate in a half-bridge mode, and adjusting the conduction time of the first rectifier circuit in the AC signal cycle, comprising the following steps:

[0078] Step S220: controlling the inverter circuit to operate in a half-bridge mode.

[0079] Step S230: In the half-bridge mode, adjusting the control parameters of the inverter circuit, wherein the control parameters include the driving frequency of the inverter circuit or the duty cycle of the pulse width modulation signal.

[0080] In the half-bridge mode, the driving frequency of the inverter circuit or the duty cycle of the pulse width modulation signal is further adjusted to reduce the bus voltage of the power supply circuit. For example, the driving frequency of the inverter switch in the inverter circuit is adjusted, or the duty cycle of the pulse width modulation signal of the inverter switch in the inverter circuit is adjusted, or both the driving frequency of the inverter switch and the duty cycle of the pulse width modulation signal in the inverter circuit are adjusted. The order of the driving frequency adjustment and the duty cycle adjustment may not be limited; the specific amplitude and number of control parameter adjustments may 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.

[0081] Step S240: adjusting the conduction time of the first rectifier circuit within the AC signal cycle.

[0082] Step S250: determine whether the actual heating power is equal to the target heating power, if so, stop power adjustment and heat the food with the current actual heating power. If not, return to step S230.

[0083] This embodiment controls the inverter circuit to operate in the half-bridge mode, adjusts the control parameters of the inverter circuit in the half-bridge mode, and adjusts the conduction time of the first rectifier circuit in the AC signal cycle. If the actual heating power is not reduced to the target heating power, the control parameters of the inverter circuit and the conduction time of the first rectifier circuit in the AC signal cycle are further adjusted. By comprehensively adjusting multiple parameters such as the operating mode of the inverter circuit, the control parameters of the inverter circuit, and the conduction time of the first rectifier circuit in the AC signal cycle, precise adjustment of the target heating power is achieved.

[0084] It is worth noting that there is no restriction on the conduction time of the first rectifier circuit and the adjustment sequence and number of times of the control parameters of the inverter circuit.

[0085] In one embodiment, since the inverter circuit is an H-bridge structure, when the inverter circuit operates in a half-bridge mode, different inverter switches can be controlled to operate to form different half-bridges. When the inverter circuit operates in a half-bridge mode, only one half-bridge can be controlled to operate. Alternatively, in order to balance the losses of the inverter switches constituting the inverter circuit, two half-bridges can be controlled to operate alternately.

[0086] In one embodiment, the power supply circuit further includes a current transformer electrically connected to the inverter circuit and a second rectifier circuit electrically connected to the current transformer. The control method further includes:

[0087] Step S600: obtaining an output electrical signal of the inverter circuit through a current transformer.

[0088] When the microwave heating device is working at a target heating power of less than 500 W, if the current signal is detected by resistance detection, the current may not be detected. Therefore, in this embodiment, the output electrical signal of the inverter circuit is obtained by a current transformer.

[0089] Step S700: rectifying the output electrical signal through a second rectifying circuit.

[0090] The output electrical signal is rectified by the second rectifier circuit to convert the AC output electrical signal into a DC signal.

[0091] Step S800: determining the actual heating power based on the rectified output electrical signal, and judging whether the actual heating power drops to the target heating power.

[0092] In response to the actual heating power being greater than the target heating power, the steps of adjusting the control parameters of the inverter circuit and adjusting the conduction time of the first rectifier circuit in the AC signal cycle are performed until the actual heating power drops to the target heating power. That is, if the actual heating power is greater than the target heating power, the steps after step S200 are continued.

[0093] This embodiment obtains the output signal of the inverter circuit through the current transformer and the second rectifier circuit to ensure the validity of the output signal of the inverter circuit, thereby obtaining the actual heating power of the effective microwave heating device and achieving accurate adjustment of the target heating power.

[0094] It is worth noting that the execution of step S600 to step S800 may be performed when the actual heating power of the microwave heating device is obtained.

[0095] The present application provides a computer storage medium, referring to Figure 7 , Figure 71 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.

[0096] 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 first rectifier circuit and an inverter circuit, 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, the inverter circuit is controlled to operate in half-bridge mode, and the conduction time of the first rectifier circuit within the AC signal cycle 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 controlling the inverter circuit to operate in a half-bridge mode and adjusting the conduction time of the first rectifier circuit in an AC signal cycle includes: Controlling the inverter circuit to operate in a half-bridge mode; In the half-bridge mode, 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; The conduction time of the first rectifier circuit in the AC signal cycle is adjusted to reduce the actual heating power to the target heating power.

3. The control method according to claim 2, characterized in that: The power supply circuit further includes a current transformer electrically connected to the inverter circuit and a second rectifier circuit electrically connected to the current transformer, and the control method further includes: Acquiring an output electrical signal of the inverter circuit through the current transformer; rectifying the output electrical signal by the second rectifying circuit; determining whether the actual heating power drops to the target heating power based on the rectified output electrical signal; In response to the actual heating power being greater than the target heating power, the step of adjusting the control parameters of the inverter circuit and the step of adjusting the conduction time of the first rectifier circuit within the AC signal cycle are executed until the actual heating power drops to the target heating power.

4. 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 inverter circuit to operate in a full-bridge mode; In the full-bridge mode, the control parameters of the inverter circuit are adjusted; 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.

5. The control method according to claim 1, characterized in that: The first rectifier circuit includes a rectifier bridge, and the control method further includes: Performing zero-crossing detection on the AC signal input to the rectifier bridge to determine the positive half-cycle and the negative half-cycle of the AC signal; The adjusting the conduction time of the first rectifier circuit within the AC signal cycle includes: The conduction time of the upper bridge arm of the rectifier bridge in the positive half cycle is shortened, or the conduction time of the lower bridge arm of the rectifier bridge in the negative half cycle is shortened.

6. The control method according to claim 5, characterized in that: The conduction time of the upper bridge arm 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 lower bridge arm is symmetrical with the time point corresponding to the trough of the AC signal in the negative half cycle as the midpoint.

7. The control method according to claim 5, characterized in that: The conduction time length of the upper bridge arm is the same as the conduction time length of the lower bridge arm.

8. 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: In the first rectifier circuit, at least one bridge arm is provided with a controllable transistor, and the controllable transistor is used to conduct the corresponding bridge arm; an inverter circuit electrically connected to the first rectifier circuit and the microwave generating circuit of the microwave heating device; Among them, the controllable tube and the inverter circuit 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 7 to control the operation of the first rectifier circuit and the inverter circuit, thereby controlling the heating power of the microwave generating circuit.

9. The power supply circuit according to claim 8, characterized in that: The power supply circuit further includes: A current transformer connected to the inverter circuit; The second rectifier circuit is connected to the current transformer and the control circuit.

10. A microwave heating device, characterized in that: include: The power supply circuit, control circuit and microwave generating circuit described in any one of claims 8-9, wherein the microwave generating circuit is electrically connected to the inverter circuit, and the control circuit adopts the control method described in any one of claims 1 to 7 to control the operation of the first rectifier circuit and the inverter circuit 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, and the computer program instructions can be executed by a processor to perform the control method according to any one of claims 1 to 7.

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