阅读说明：本技术 电磁加热控制方法、装置及电磁加热设备 (Electromagnetic heating control method and device and electromagnetic heating equipment ) 是由 任富佳 李信合 于 2021-09-23 设计创作，主要内容包括：本发明提供了一种电磁加热控制方法、装置及电磁加热设备,在接收到加热指令后,首先获取供电电路的电压检测数据,然后在电压检测数据指示电压信号对应的电压值为过零点的时刻与电压检测数据指示电压信号对应的电压值为过零点相邻的峰值点的时刻之间,输出脉冲宽度按照预先确定的变化趋势变化的脉冲信号,控制开关管电路导通或断开,以使得加热电路进行加热。本发明通过输出脉冲宽度按照预先确定的变化趋势变化的脉冲信号控制开关管电路导通或断开,以降低电感线圈产生的反向电动势,降低了电磁干扰。(The invention provides an electromagnetic heating control method, an electromagnetic heating control device and electromagnetic heating equipment. The invention controls the on-off of the switching tube circuit by outputting the pulse signal of which the pulse width changes according to the predetermined change trend so as to reduce the back electromotive force generated by the inductance coil and reduce the electromagnetic interference.)

1. An electromagnetic heating control method is characterized in that the method is applied to a controller of an electromagnetic heating device; the electromagnetic heating equipment also comprises a power supply circuit, a switching tube circuit and a heating circuit; the power supply circuit, the controller, the switching tube circuit and the heating circuit are connected in sequence; the method comprises the following steps:

after a heating instruction is received, voltage detection data of the power supply circuit are obtained; the voltage detection data indicate a voltage value corresponding to a voltage signal output by the power supply circuit;

and outputting a pulse signal with the pulse width changing according to a predetermined change trend between the moment when the voltage detection data indicates that the voltage value corresponding to the voltage signal is a zero crossing point and the moment when the voltage detection data indicates that the voltage value corresponding to the voltage signal is a peak point adjacent to the zero crossing point.

2. The method of claim 1, further comprising:

and outputting a pulse signal with a pulse width changing according to a predetermined change trend between the moment when the voltage detection data indicates that the voltage value corresponding to the voltage signal is a peak point and the moment when the voltage detection data indicates that the voltage value corresponding to the voltage signal is a zero crossing point adjacent to the peak point, and controlling the switching tube circuit to be switched on or switched off so as to heat the heating circuit.

3. The method of claim 1 or 2, wherein the trend of change comprises a first target pulse width and a second target pulse width;

the step of outputting a pulse signal whose pulse width changes according to a predetermined trend of change includes:

and outputting a pulse signal of which the pulse width is increased to a first target pulse width and then reduced to a second target pulse width according to a predetermined change trend.

4. The method of claim 2,

outputting a pulse signal of which the pulse width is increased to a third target pulse width firstly and then reduced to a fourth target pulse width according to a predetermined change trend between the time when the voltage detection data indicates that the voltage value corresponding to the voltage signal is a zero crossing point and the time when the voltage detection data indicates that the voltage value corresponding to the voltage signal is a peak point adjacent to the zero crossing point;

and outputting a pulse signal of which the pulse width is increased to a fifth target pulse width and then decreased to a sixth target pulse width according to a predetermined change trend between the time when the voltage detection data indicates that the voltage value corresponding to the voltage signal is the peak point and the time when the voltage detection data indicates that the voltage value corresponding to the voltage signal is the zero crossing point adjacent to the peak point.

5. The method according to claim 1, wherein the trend of change comprises a time delay duration and a preset width;

outputting a pulse signal with a pulse width of a preset width within a delay time after the voltage detection data indicates that the voltage value corresponding to the voltage signal is a zero crossing point;

and outputting a pulse signal with the pulse width increasing and then decreasing according to a predetermined change trend between the time after the delay time and the time when the voltage detection data indicates that the voltage value corresponding to the voltage signal is the peak point adjacent to the zero crossing point.

6. The method of claim 1, wherein the trend of change comprises a first delay time duration and a second delay time duration and a preset width;

within a first delay time after the voltage detection data indicates that the voltage value corresponding to the voltage signal is a zero crossing point, outputting a pulse signal with a pulse width of a preset width;

outputting a pulse signal with the pulse width increasing and then decreasing according to a predetermined change trend between the time after the first delay time and the time corresponding to a second delay time before the voltage detection data indicates that the voltage value corresponding to the voltage signal is the peak point adjacent to the zero crossing point;

and outputting a pulse signal with the pulse width of a preset width between the second delay time and the peak point.

7. The method of claim 1,

within a third delay time period after the voltage detection data indicates that the voltage value corresponding to the voltage signal is a zero crossing point, outputting a pulse signal with a pulse width of a first preset width;

outputting a pulse signal with the pulse width increasing and then decreasing according to a predetermined change trend between the time after the third delay time and the time corresponding to a fourth delay time before the voltage detection data indicates that the voltage value corresponding to the voltage signal is the peak point adjacent to the zero crossing point;

after the fourth delay time length, outputting a pulse signal with a pulse width of a first preset width to the peak point;

within a fifth delay time after the voltage detection data indicates that the voltage value corresponding to the voltage signal is the peak point, outputting a pulse signal with a pulse width of a second preset width;

outputting a pulse signal with the pulse width increasing and then decreasing according to a predetermined change trend between the time after the fifth delay time and the time corresponding to a sixth delay time before the voltage detection data indicates that the voltage value corresponding to the voltage signal is the zero crossing point adjacent to the peak point;

and outputting a pulse signal with a pulse width of a second preset width between the sixth delay time length and the zero crossing point.

8. The method of claim 1, wherein the voltage signal output by the power supply circuit is a periodically varying signal;

before the step of outputting the pulse signal whose pulse width changes according to the predetermined trend, the method further includes:

determining a variation period of a voltage signal output by the power supply circuit based on the voltage detection data;

and taking half of the signal period as the change period of the pulse signal.

9. The method according to claim 8, wherein the voltage signal output by the power supply circuit is a dc steamed bun wave signal obtained by filtering and rectifying the mains supply;

the step of determining a variation cycle of a voltage signal output by the power supply circuit based on the voltage detection data includes:

determining the time interval of adjacent zero crossing points and peak points of the direct current steamed bread wave signal based on the voltage detection data;

taking twice of the time interval between the zero crossing point and the peak point as the change period of the direct-current steamed bread wave signal;

alternatively, the first and second electrodes may be,

determining the time interval of two adjacent zero-crossing points of the direct current steamed bread wave signal based on the voltage detection data;

taking the time interval of the two zero-crossing points as the change period of the direct-current steamed bun wave signal;

alternatively, the first and second electrodes may be,

determining a time interval of two adjacent peak points of the voltage signal output by the power supply circuit based on the voltage detection data;

and taking the time interval of the two peak points as the change period of the direct current steamed bread wave signal.

10. The method of claim 9, wherein the trend of change is generated by:

acquiring real-time power of the heating circuit;

based on the real-time power of the heating circuit and the preset power acquired in advance, the pulse width of each pulse signal in the change period of the pulse signal is adjusted until the absolute value of the difference value between the real-time power of the heating module of the electromagnetic heating equipment and the preset power is smaller than or equal to a preset threshold value;

and determining the pulse width of each pulse signal in the adjusted change period of the pulse signal as the change trend.

11. The electromagnetic heating control device is characterized in that the device is arranged on a controller of electromagnetic heating equipment; the electromagnetic heating equipment also comprises a power supply circuit, a switching tube circuit and a heating circuit; the power supply circuit, the controller, the switching tube circuit and the heating circuit are connected in sequence; the device comprises:

the voltage detection module is used for acquiring voltage detection data of the power supply circuit after receiving the heating instruction; the voltage detection data indicate a voltage value corresponding to a voltage signal output by the power supply circuit;

and the control signal output module is used for outputting a pulse signal of which the pulse width changes according to a predetermined change trend between the moment when the voltage detection data indicates that the voltage value corresponding to the voltage signal is a zero crossing point and the moment when the voltage detection data indicates that the voltage value corresponding to the voltage signal is a peak point adjacent to the zero crossing point.

12. An electromagnetic heating device is characterized by comprising a controller, a power supply circuit, a switching tube circuit and a heating circuit; the power supply circuit, the switching tube circuit and the heating circuit are sequentially connected; the controller is respectively connected with the power supply circuit, the switching tube circuit and the heating circuit; the apparatus of claim 11 disposed in the controller.

13. An electronic device, comprising a processor and a memory, the memory storing computer-executable instructions executable by the processor, the processor executing the computer-executable instructions to implement the electromagnetic heating control method of any one of claims 1 to 10.

14. A computer-readable storage medium having stored thereon computer-executable instructions that, when invoked and executed by a processor, cause the processor to implement the electromagnetic heating control method of any of claims 1 to 10.

Technical Field

The invention relates to the technical field of control, in particular to an electromagnetic heating control method and device and electromagnetic heating equipment.

Background

In the related art, a controller is generally used to control the on and off of the switching tube to control the heating function of the electromagnetic device. When a heating command is received, the controller outputs a control signal with a fixed pulse width to drive the switching tube to be switched on and off, however, in the method, the switching tube is easily burnt under the condition that the power supply voltage is changed to a larger voltage, and the electromagnetic interference is stronger.

Disclosure of Invention

In view of the above, the present invention provides an electromagnetic heating control method, an electromagnetic heating control device and an electromagnetic heating apparatus, so as to reduce electromagnetic interference.

In a first aspect, an embodiment of the present invention provides an electromagnetic heating control method, which is applied to a controller of an electromagnetic heating device; the electromagnetic heating equipment also comprises a power supply circuit, a switching tube circuit and a heating circuit; the power supply circuit, the controller, the switching tube circuit and the heating circuit are connected; the method comprises the following steps: after receiving the heating instruction, acquiring voltage detection data of the power supply circuit; the voltage detection data indicate voltage values corresponding to voltage signals output by the power supply circuit; and outputting a pulse signal with the pulse width changing according to a predetermined change trend between the moment when the voltage value corresponding to the voltage detection data indication voltage signal is a zero crossing point and the moment when the voltage value corresponding to the voltage detection data indication voltage signal is a peak point adjacent to the zero crossing point.

Further, the method further comprises: and outputting a pulse signal with the pulse width changing according to a predetermined change trend between the moment when the voltage value corresponding to the voltage detection data indication voltage signal is the peak point and the moment when the voltage value corresponding to the voltage detection data indication voltage signal is the zero crossing point adjacent to the peak point, and controlling the switching tube circuit to be switched on or switched off so as to heat the heating circuit.

Further, the variation trend comprises a first target pulse width and a second target pulse width; the step of outputting a pulse signal whose pulse width changes according to a predetermined trend of change includes: and outputting a pulse signal of which the pulse width is increased to a first target pulse width and then reduced to a second target pulse width according to a predetermined change trend.

Further, between the moment when the voltage value corresponding to the voltage detection data indication voltage signal is a zero crossing point and the moment when the voltage value corresponding to the voltage detection data indication voltage signal is a peak point adjacent to the zero crossing point, outputting a pulse signal of which the pulse width is increased to a third target pulse width and then decreased to a fourth target pulse width according to a predetermined change trend; and outputting a pulse signal of which the pulse width is increased to a fifth target pulse width and then decreased to a sixth target pulse width according to a predetermined change trend between the moment when the voltage value corresponding to the voltage detection data indication voltage signal is the peak point and the moment when the voltage value corresponding to the voltage detection data indication voltage signal is the zero crossing point adjacent to the peak point.

Further, the variation trend comprises a delay time and a preset width; outputting a pulse signal with a pulse width of a preset width in a delay time after the voltage detection data indicates that the voltage value corresponding to the voltage signal is a zero crossing point; and outputting a pulse signal with the pulse width increasing and then decreasing according to a predetermined change trend between the time after the delay time and the time when the voltage value corresponding to the voltage detection data indication voltage signal is the peak point adjacent to the zero crossing point.

Further, the variation trend comprises a first delay time length, a second delay time length and a preset width; outputting a pulse signal with a pulse width of a preset width within a first delay time after the voltage detection data indicates that the voltage value corresponding to the voltage signal is a zero crossing point; outputting a pulse signal with the pulse width increasing and then decreasing according to a predetermined change trend between the time after the first delay time and the time corresponding to a second delay time before the voltage value corresponding to the voltage detection data indication voltage signal is the peak point adjacent to the zero crossing point; and outputting a pulse signal with the pulse width of the preset width between the second delay time length and the peak point.

Further, within a third delay time period after the voltage detection data indicates that the voltage value corresponding to the voltage signal is the zero-crossing point, outputting a pulse signal with a pulse width of a first preset width; outputting a pulse signal with the pulse width increasing and then decreasing according to a predetermined change trend between the time after the third delay time and the time corresponding to the fourth delay time before the voltage value corresponding to the voltage detection data indication voltage signal is the peak point adjacent to the zero crossing point; after the fourth delay time length to the peak point, outputting a pulse signal with the pulse width of the first preset width; outputting a pulse signal with a pulse width of a second preset width within a fifth delay time after the voltage detection data indicates that the voltage value corresponding to the voltage signal is the peak point; outputting a pulse signal with the pulse width increasing and then decreasing according to a predetermined change trend between the time after the fifth delay time and the time corresponding to the sixth delay time before the voltage value corresponding to the voltage detection data indication voltage signal is the zero crossing point adjacent to the peak point; and outputting a pulse signal with the pulse width of a second preset width between the sixth delay time length and the zero crossing point.

Further, the voltage signal output by the power supply circuit is a periodic variation signal; before the step of outputting the pulse signal whose pulse width changes according to the predetermined trend, the method further includes: determining a variation period of a voltage signal output by the power supply circuit based on the voltage detection data; half of the signal period is taken as the change period of the pulse signal.

Further, the voltage signal output by the power supply circuit is a direct-current steamed bun wave signal obtained by filtering and rectifying the mains supply; the step of determining a variation cycle of a voltage signal output by the power supply circuit based on the voltage detection data includes: determining the time interval of adjacent zero crossing points and peak points of the direct-current steamed bun wave signal based on the voltage detection data; twice the time interval between the zero crossing point and the peak point is used as the change period of the direct-current steamed bread wave signal; or determining the time interval of two adjacent zero-crossing points of the direct-current steamed bread wave signal based on the voltage detection data; taking the time interval of the two zero-crossing points as the change period of the direct-current steamed bun wave signal; or, based on the voltage detection data, determining the time interval of two adjacent peak points of the voltage signal output by the power supply circuit; and taking the time interval of the two peak points as the change period of the direct current steamed bread signal.

Further, the above-described variation tendency is generated by: acquiring real-time power of a heating circuit; based on the real-time power of the heating circuit and the preset power acquired in advance, the pulse width of each pulse signal in the change period of the pulse signal is adjusted until the absolute value of the difference value between the real-time power of the heating module and the preset power is smaller than or equal to a preset threshold value; and determining the pulse width of each pulse signal in the change period of the adjusted pulse signal as a change trend.

In a second aspect, an embodiment of the present invention further provides an electromagnetic heating control apparatus, where the apparatus is disposed in a controller of an electromagnetic heating device; the electromagnetic heating equipment also comprises a power supply circuit, a switching tube circuit and a heating circuit; the power supply circuit, the controller, the switching tube circuit and the heating circuit are connected; the device includes: the voltage detection module is used for acquiring voltage detection data of the power supply circuit after receiving the heating instruction; the voltage detection data indicate voltage values corresponding to voltage signals output by the power supply circuit; and the control signal output module is used for outputting a pulse signal of which the pulse width changes according to a predetermined change trend between the moment when the voltage value corresponding to the voltage detection data indication voltage signal is a zero crossing point and the moment when the voltage value corresponding to the voltage detection data indication voltage signal is a peak point adjacent to the zero crossing point.

In a third aspect, an embodiment of the present invention further provides an electromagnetic heating apparatus, including a controller, a power supply circuit, a switching tube circuit, and a heating circuit; the power supply circuit, the switching tube circuit and the heating circuit are sequentially connected; the controller is respectively connected with the power supply circuit, the switching tube circuit and the heating circuit; the device is arranged on the controller.

In a fourth aspect, an embodiment of the present invention further provides an electronic device, where the electronic device includes a processor and a memory, where the memory stores computer-executable instructions that can be executed by the processor, and the processor executes the computer-executable instructions to implement the electromagnetic heating control method.

In a fifth aspect, the embodiment of the present invention further provides a computer-readable storage medium, where the computer-readable storage medium stores computer-executable instructions, and when the computer-executable instructions are called and executed by a processor, the computer-executable instructions cause the processor to implement the above-mentioned electromagnetic heating control method.

The embodiment of the invention has the following beneficial effects:

the embodiment of the invention provides an electromagnetic heating control method, an electromagnetic heating control device and electromagnetic heating equipment. The mode controls the switching tube circuit to be switched on or switched off by outputting the pulse signal of which the pulse width changes according to the predetermined change trend so as to reduce the back electromotive force generated by the inductance coil and reduce the electromagnetic interference.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic structural diagram of an electromagnetic heating apparatus according to an embodiment of the present invention;

fig. 2 is a flowchart of an electromagnetic heating control method according to an embodiment of the present invention;

fig. 3 is a waveform diagram of a pulse width signal in the electromagnetic heating control method according to the embodiment of the present invention;

FIG. 4 is a waveform diagram of another pulse width signal in the electromagnetic heating control method according to the embodiment of the present invention;

FIG. 5 is a waveform diagram of another pulse width signal in the electromagnetic heating control method according to the embodiment of the present invention;

FIG. 6 is a waveform diagram of another pulse width signal in the electromagnetic heating control method according to the embodiment of the present invention;

FIG. 7 is a waveform diagram of another pulse width signal in the electromagnetic heating control method according to the embodiment of the present invention;

fig. 8 is a schematic structural diagram of an electromagnetic heating control device according to an embodiment of the present invention;

fig. 9 is a schematic structural diagram of another electromagnetic heating apparatus provided in the embodiment of the present invention;

fig. 10 is a schematic structural diagram of another electromagnetic heating apparatus provided in the embodiment of the present invention;

fig. 11 is a comparison graph of a voltage waveform of a mains supply, a rectified voltage waveform, an envelope waveform of an IGBT collector voltage, and a pulse waveform output by a controller according to an embodiment of the present invention;

fig. 12 is a flowchart illustrating detection of zero crossing points and peak points in an electromagnetic heating control method according to an embodiment of the present invention;

FIG. 13 is a flow chart of another electromagnetic heating control method provided by an embodiment of the present invention;

fig. 14 is a comparison graph of a voltage waveform of a commercial power, a voltage waveform after rectification, an envelope waveform of an IGBT collector voltage, and a pulse waveform output by a controller when a pulse width of a first half cycle of a rectified power waveform is changed according to an embodiment of the present invention;

fig. 15 is a comparison graph of a voltage waveform of a commercial power, a rectified voltage waveform, an envelope waveform of an IGBT collector voltage, and a pulse waveform output by a controller when a pulse width of a second half cycle of a rectified power waveform is changed according to an embodiment of the present invention;

fig. 16 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.

Detailed Description

To make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

At present, most of electromagnetic heating devices (such as induction cookers) commonly used in the market adopt a single-tube parallel inversion topological structure to control the heating process of the device, and Insulated Gate Bipolar Transistors (IGBTs) in power switch tubes are selected. Based on the structure, the heating control method of the electromagnetic heating equipment specifically comprises the following steps: when a heating command is received, a controller (MCU) outputs a Control signal with a fixed pulse width according to a currently received power stage to drive the IGBT switch tube to perform heating operation, and the pulse width of the Control signal is kept constant in the entire period of the ac power.

In the process, when the alternating current for supplying the electric energy to the electromagnetic heating equipment is near the zero crossing point, the charging current of the coil panel of the heating circuit is small due to low voltage, and when the IGBT is turned off, the back electromotive force generated by the inductance of the coil panel is small, so that the electromagnetic interference is weaker; when the IGBT is turned off, the back electromotive force generated by the coil inductance is large (i.e., the collector voltage of the IGBT is high), and the electromagnetic Interference is strong, which easily causes the IGBT to burn out and the EMI (Electro-Magnetic Interference) test to be unqualified.

Based on this, the electromagnetic heating control method and device and the electromagnetic heating equipment provided by the embodiment of the invention can be used for heating scenes of various foods.

For the convenience of understanding the present embodiment, a detailed description will be given to an electromagnetic heating control method disclosed in the present embodiment.

The embodiment of the invention provides an electromagnetic heating control method, which is applied to a controller 20 of an electromagnetic heating device; as shown in fig. 1, the electromagnetic heating apparatus further includes a power supply circuit 10, a switching tube circuit 30, and a heating circuit 40; the power supply circuit, the controller, the switching tube circuit and the heating circuit are connected. As shown in fig. 2, the method comprises the steps of:

and step S200, acquiring voltage detection data of the power supply circuit after receiving the heating instruction. The voltage detection data indicate voltage values corresponding to the voltage signals output by the power supply circuit.

The voltage detection data can be obtained by sampling the power supply circuit through a detection circuit. The power supply circuit may be a power supply for supplying an alternating current, and may include a circuit configuration for performing processing such as filtering and rectification on the alternating current. When the power supply module is a power supply for providing alternating current, the voltage detected by the detection circuit has a positive value and a negative value, and when the voltage value output by the power supply module is determined, absolute value processing needs to be carried out on voltage detection data. When the voltage output by the power supply circuit is the rectified direct-current voltage, the voltage detection data can be directly adopted to determine the magnitude of the voltage value output by the power supply module.

The voltage signal output by the power supply circuit is a periodic variation signal; after the voltage detection data is acquired, the change period of the voltage signal output by the power supply circuit may be determined based on the voltage detection data, and half of the signal period may be used as the change period of the pulse signal. Specifically, the time interval of adjacent zero crossing points and peak points of the direct-current steamed bun wave signal can be determined based on the voltage detection data; twice the time interval between the zero crossing point and the peak point is used as the change period of the direct-current steamed bread wave signal; or determining the time interval of two adjacent zero-crossing points of the direct-current steamed bread wave signal based on the voltage detection data; taking the time interval of the two zero-crossing points as the change period of the direct-current steamed bun wave signal; or, based on the voltage detection data, determining the time interval of two adjacent peak points of the voltage signal output by the power supply circuit; and taking the time interval of the two peak points as the change period of the direct current steamed bread signal.

Since the process of acquiring the voltage monitoring data of the power supply circuit is generally a sampling process, it is difficult to sample when the power supply voltage is at a zero crossing point, and therefore, when the voltage detection data is lower than a set voltage threshold, it can be considered that the voltage output by the power supply circuit is at the zero crossing point. Similarly, when the voltage detection data is higher than the set voltage threshold, the voltage output by the power supply circuit is considered to be just at the peak point.

Step S202 is to output a pulse signal having a pulse width that changes according to a predetermined trend between a time at which the voltage value corresponding to the voltage detection data indicating voltage signal is a zero-crossing point and a time at which the voltage value corresponding to the voltage detection data indicating voltage signal is a peak point adjacent to the zero-crossing point.

The above-mentioned variation tendency is generally that the pulse width becomes larger and then smaller. The variation trend of the pulse width needs to meet the power of electromagnetic heating on one hand, so that the pulse width cannot be too wide when the power supply voltage is small (close to the zero-crossing position); on the other hand, in order to reduce the large voltage of the power supply circuit, the pulse width cannot be too wide when the power supply voltage is large (near the peak point position) due to the large back electromotive force generated by the tubular state change of the switch. Therefore, the change trend of the pulse width is set to be larger and then smaller, and the requirements in the two aspects can be met.

In order to satisfy the variation trend of the pulse width with the power of the electromagnetic heating, the variation rule can be determined by the following method: firstly, acquiring real-time power of a heating circuit; then based on the real-time power of the heating circuit and the preset power acquired in advance, the pulse width of each pulse signal in the change period of the pulse signal is adjusted until the absolute value of the difference value between the real-time power of the heating module and the preset power is smaller than or equal to a preset threshold value; and finally determining the pulse width of each pulse signal in the change period of the adjusted pulse signal as a change trend.

For the same reason, in the next half cycle (i.e., between adjacent peak points and zero-crossing points), pulse information in which the pulse width changes according to a predetermined trend of change may be output to reduce the generated back electromotive force and reduce electromagnetic interference. The variation trend here may be the same as or different from that of the first half cycle. Specifically, a pulse signal with a pulse width that changes according to a predetermined trend of change is output between the time when the voltage value corresponding to the voltage detection data indication voltage signal is a peak point and the time when the voltage value corresponding to the voltage detection data indication voltage signal is a zero-crossing point adjacent to the peak point, and the switching tube circuit is controlled to be turned on or off so that the heating circuit heats.

In a specific implementation, a target pulse width pointed by a variation trend is generally considered, specifically, the variation trend may include a first target pulse width and a second target pulse width; in the upper half cycle (time Tz 1-Tp 1, where Tz1 is the time corresponding to the zero-crossing point, and Tp1 is the time corresponding to the peak point) and the lower half cycle (time Tp 1-T z2, where Tz2 is the time corresponding to the zero-crossing point), pulse signals with pulse widths that are increased to the first target pulse width W1 and then decreased to the second target pulse width W2 according to a predetermined trend are output, as shown in fig. 3.

In addition, the change trend can be pointed to different target pulse widths in the pulse output process of the upper half period and the lower half period. Specifically, the variation trend may include a third target pulse width, a fourth target pulse width, a fifth target pulse width, and a sixth target pulse width; in the last half period (Tz 1-Tp 1), namely between the time when the voltage value corresponding to the voltage detection data indication voltage signal is a zero crossing point and the time when the voltage value corresponding to the voltage detection data indication voltage signal is a peak point adjacent to the zero crossing point, outputting a pulse signal of which the pulse width is increased to a third target pulse width W3 and then is decreased to a fourth target pulse width W4 according to a predetermined change trend; in the next half period (time Tp 1-T z 2), that is, between the time when the voltage value corresponding to the voltage detection data indication voltage signal is at the peak point and the time when the voltage value corresponding to the voltage detection data indication voltage signal is at the zero-crossing point adjacent to the peak point, the pulse signal with the pulse width increased to the fifth target pulse width W5 and then decreased to the sixth target pulse width W6 according to the predetermined trend is output, as shown in fig. 4.

In a specific implementation, it is also considered to set a part of the pulse with the unchanged width in the variation trend. The occurrence time of the pulses with the unchanged widths can be called delay time, and the widths of the pulses can be preset widths. Specifically, the variation trend includes a delay time and a preset width; in the last half period (within the time Tz 1-Tp 1), outputting a pulse signal with the pulse width of the preset width W0 within the delay time t after the time when the voltage detection data indicate that the voltage value corresponding to the voltage signal is the zero crossing point; between the time after the delay time and the time when the voltage value corresponding to the voltage detection data indication voltage signal is the peak point adjacent to the zero crossing point, a pulse signal whose pulse width is increased and then decreased according to a predetermined variation trend is output, as shown in fig. 5.

In addition, two delay times can be set near the zero crossing point and the peak point respectively. Specifically, the trend may include a first delay time duration, a second delay time duration, and a preset width. In the last half period (within the time of Tz 1-Tp 1), outputting a pulse signal with a pulse width of a preset width within a first delay time period ty1 after the time when the voltage detection data indicate that the voltage value corresponding to the voltage signal is a zero crossing point; outputting a pulse signal with the pulse width increasing and then decreasing according to a predetermined change trend between the time after the first delay time and the time corresponding to a second delay time ty2 before the voltage value corresponding to the voltage detection data indicating voltage signal is the peak point adjacent to the zero crossing point; after the second delay time period ty2 to the peak point, a pulse signal with a preset pulse width is output, as shown in fig. 6. When the pulse with the variable width is output in the lower half period, the same delay time and preset width as those in the upper half period can be adopted.

Of course, a different delay time and preset width may be used in the lower half of the cycle than in the upper half of the cycle. Specifically, the trend may include a third delay time duration, a fourth delay time duration, a fifth delay time duration, a sixth delay time duration, a first preset width, and a second preset width. In the last half period (Tz 1-Tp 1), outputting a pulse signal with a pulse width of a first preset width W01 within a third delay time period ty3 after the time when the voltage detection data indicate that the voltage value corresponding to the voltage signal is a zero crossing point; outputting a pulse signal with the pulse width increasing and then decreasing according to a predetermined change trend between the time after the third delay time period ty3 and the time before the voltage value corresponding to the voltage detection data indicating the voltage signal is the peak point adjacent to the zero crossing point and corresponding to the fourth delay time period ty 4; after the fourth delay time period ty4 to the peak point, a pulse signal with a pulse width of the first preset width W01 is output. In the next half period (within the time period Tp 1-T z 2), outputting a pulse signal with the pulse width of a second preset width W02 within a fifth delay time period ty5 after the voltage detection data indicate that the voltage value corresponding to the voltage signal is the peak point; outputting a pulse signal with the pulse width increasing and then decreasing according to a predetermined change trend between the time after the fifth delay time period ty5 and the time corresponding to the sixth delay time period ty6 before the voltage value corresponding to the voltage detection data indicating the voltage signal is the zero crossing point adjacent to the peak point; after the sixth delay period ty6 until the zero-crossing point, a pulse signal having a pulse width of the second preset width W02 is output, as shown in fig. 7.

The embodiment of the invention provides an electromagnetic heating control method, which comprises the steps of firstly obtaining voltage detection data of a power supply circuit after a heating instruction is received, then outputting a pulse signal with the pulse width changing according to a predetermined change trend between the time when a voltage value corresponding to a voltage signal indicated by the voltage detection data is a zero crossing point and the time when the voltage value corresponding to the voltage signal indicated by the voltage detection data is a peak point adjacent to the zero crossing point, and controlling a switching tube circuit to be switched on or switched off so as to heat the heating circuit. The electromagnetic heating control method, the electromagnetic heating control device and the electromagnetic heating equipment control the on-off of the switching tube circuit by outputting the pulse signal of which the pulse width changes according to the predetermined change trend so as to reduce the back electromotive force generated by the inductance coil and reduce the electromagnetic interference.

Corresponding to the above method embodiment, the embodiment of the present invention further provides an electromagnetic heating control device, which is disposed in a controller of an electromagnetic heating apparatus; as shown in fig. 8, the apparatus includes:

the voltage detection module 800 is configured to obtain voltage detection data of the power supply circuit after receiving the heating instruction; the voltage detection data indicate voltage values corresponding to voltage signals output by the power supply circuit;

the control signal output module 802 is configured to output a pulse signal with a pulse width that changes according to a predetermined change trend between a time when the voltage value corresponding to the voltage detection data indication voltage signal is a zero-crossing point and a time when the voltage value corresponding to the voltage detection data indication voltage signal is a peak point adjacent to the zero-crossing point.

The electromagnetic heating control device provided by the embodiment of the invention has the same technical characteristics as the electromagnetic heating control method provided by the embodiment, so that the same technical problems can be solved, and the same technical effects can be achieved.

The embodiment of the invention provides another electromagnetic heating device. On the basis of the electromagnetic heating device shown in fig. 1, the apparatus further comprises a detection circuit 50, as shown in particular in fig. 9. The controller is connected with the power supply circuit through the detection circuit; the power supply circuit is connected with the heating circuit and provides electric energy for the heating circuit.

The detection circuit is used for detecting the voltage output by the power supply module to obtain a detection voltage; the controller is used for receiving the detection voltage and outputting a control signal to control the on-off of the switching tube circuit; the control signal comprises a pulse signal with variable width; the heating circuit is used for performing electromagnetic heating when the switching tube circuit is conducted.

The controller may be a single chip microcomputer or an FPGA (Field Programmable Gate Array).

Specifically, the switching tube circuit includes a switch driving circuit and a switching tube; the controller is connected with the switch driving circuit; the switching tube is connected with the heating circuit; the switch driving circuit is used for driving the switch tube to be switched on or switched off based on a control signal output by the controller; the switch tube can be an insulated gate bipolar transistor. The insulated gate bipolar transistor combines the advantages of a power transistor and a power field effect transistor, and has good characteristics.

In a specific implementation process, the power supply circuit may include a power supply module, a filter circuit and a rectifier circuit, which are connected in sequence; the rectifying circuit is connected with the detection circuit; the power supply module is used for outputting alternating current commercial power; the filter circuit is used for filtering the alternating current commercial power; the rectification module is used for converting the filtered alternating current mains supply into direct current steamed bread waves.

The detection circuit may include a voltage sampling circuit; the voltage sampling circuit is used for sampling the direct current steamed bread wave according to a set frequency to obtain a detection voltage (also called as a sampling voltage); the controller is used for obtaining a zero crossing point and a peak point of the direct current steamed bread wave based on the detection voltage; obtaining the pulse width change period of the control signal based on the zero crossing point and the peak point; obtaining the pulse width variation trend of the control signal based on the preset heating power of the heating circuit; and outputting a pulse signal with the variable width based on the pulse width variation period and the pulse width variation trend so as to control the on/off of the switching tube circuit. The pulse width variation period is usually equal to twice the time difference between the zero crossing point and the peak point of the dc voltage bread wave. In the implementation process, experiments can be carried out in advance to obtain pulse width variation trends corresponding to different heating powers; when the preset heating power of the heating circuit is determined, the pulse width variation trend can be correspondingly determined.

Wherein, the detection circuit also comprises a current detection circuit; the current detection circuit is connected with the rectification circuit and the switching tube circuit; the current detection circuit is used for detecting the current of the heating circuit; the controller is used for obtaining the pulse width variation trend of the control signal based on the current of the heating circuit and the preset heating power; and outputting a pulse signal with the variable width based on the pulse width variation period and the pulse width variation trend so as to control the on/off of the switching tube circuit. Specifically, the controller may calculate the power of the heating circuit based on the current of the heating circuit and the resistance of the heating circuit, where the power is a real-time power, adjust the real-time power to a preset heating power by adjusting the pulse width, and determine a change process of the adjusted pulse width as a pulse width change trend.

In a specific implementation process, the power supply circuit is connected with the heating circuit; the power supply circuit supplies power to the heating circuit so that the heating circuit performs electromagnetic heating when the switching tube circuit is conducted. The heating circuit may be a resonant heating circuit that performs resonant heating when the switching tube circuit is turned on.

The embodiment of the invention provides electromagnetic heating equipment, wherein a detection circuit detects the voltage output by a power supply module to obtain a detection voltage; the controller receives the detection voltage and outputs a pulse signal with variable width as a control signal to control the on/off of the switching tube circuit; the heating circuit performs electromagnetic heating when the switching tube circuit is conducted. In the mode, the controller outputs the pulse signal with the variable width to control the switch circuit to be switched on or switched off, so that the electromagnetic interference is reduced. The electromagnetic heating device provided by the embodiment of the invention has the same technical characteristics as the electromagnetic heating control device provided by the embodiment, so that the same technical problems can be solved, and the same technical effects can be achieved.

An embodiment of the present invention further provides another electromagnetic heating apparatus, as shown in fig. 10, the apparatus includes a power module, a filter circuit, a rectifier circuit, a current detection circuit, a resonant heating circuit, a switching tube, a driving circuit, a controller, and a voltage sampling circuit.

The switching tube (preferably IGBT) is connected with the resonant heating circuit and is used for controlling the resonant heating circuit to perform resonant operation; the rectifier circuit module is connected with the resonant heating circuit and provides electric energy for resonant operation; the driving circuit is connected with the switching tube and drives the switching tube to be switched on and off; the controller is connected with the driving circuit 7, and the pulse signal output end of the controller controls the electromagnetic heating device to perform heating work. One end of the filter circuit is connected with the power supply module, the other end of the filter circuit is connected with the rectifying circuit, the power supply module provides electric energy for the electromagnetic heating device, the filter circuit filters interference signals generated by the power supply module and the rectifying module, and the rectifying circuit converts the filtered alternating current mains supply into direct current bread waves; the sampling end of the voltage sampling circuit is connected with the rectifying circuit, the sampling signal output end is connected with the controller, and the collected voltage signal of the rectified power supply is sent to the controller, so that the controller judges the specific position of the waveform of the rectified power supply in an alternating current period according to the voltage detection signal; the first end of the current detection circuit is connected with the negative electrode output end of the rectification circuit, the second end of the current detection circuit is connected with the first stage (if the switching tube is an IGBT, the first stage is E stage) of the switching tube, and the detection signal output end is connected with the controller, so that the controller judges the output width of the pulse signal according to the current detection signal and the current target power; the voltage waveform of the mains supply, the rectified voltage waveform, the envelope waveform of the collector voltage of the IGBT, and the pulse waveform output by the controller are shown in fig. 11.

Based on the device, the method for controlling the electromagnetic heating can be realized, and the method is applied to the electromagnetic heating device adopting the IGBT as the switching tube. The method can reduce the voltage of the IGBT collector and reduce EMI electromagnetic interference. In the method, a controller of the electromagnetic heating device outputs a pulse signal with variable pulse width in one period of rectified power supply voltage, after the zero point of the power supply voltage is detected, the adjustment is carried out according to the change that the output pulse width is increased firstly and then reduced, after the current peak value, the adjustment is carried out according to the change that the output pulse width is increased firstly and then reduced, the treatment is carried out in the whole period, the method is superior to the method of only carrying out the treatment in half wave, and the effect of reducing the EMI electromagnetic interference is obvious. Meanwhile, the detection method firstly judges different frequency types of 50HZ or 60HZ and then adjusts the pulse width in a targeted manner, and the control mode is easy to realize and has obvious effect.

The method firstly detects the zero crossing point and the peak point of the rectified power waveform voltage, as shown in fig. 12, and specifically comprises the following steps:

1. the controller detects the voltage value every predetermined time (e.g., 125us) by the voltage sampling circuit.

2. And when the detected voltage is the highest point, the zero crossing point of the rectified power waveform is formed. The zero-crossing point detection can be realized by a zero-crossing detection circuit.

3. Whether the current voltage is 50Hz or 60Hz is determined by 2 times the time interval between the voltage peak point and the zero crossing point (set as T0) (the zero crossing period of the 50Hz alternating current power supply is 10ms, and the zero crossing period of the 60Hz alternating current power supply is 8.3 ms).

In addition, the algorithm for judging whether the current ac power is 50Hz or 60Hz may use the following method:

a. the controller 8 detects a voltage value every predetermined time (for example, 125us) through the voltage sampling circuit, and a zero-crossing point is obtained when the detected voltage is the lowest point; the peak point is when the detected voltage is the highest point.

b. Whether the present voltage is 50Hz or 60Hz is determined by the time interval of two zero-crossings (set to T0).

c. It is determined whether the current voltage is 50Hz or 60Hz by the time interval of two peak points (set to T0).

The heating control process of the electromagnetic heating device by the method is shown in fig. 13, and is specifically realized by the following steps:

and step 1, receiving a heating command.

And 2, outputting a pulse signal by the controller to drive the switching tube to be switched on and off so as to enable the resonant heating circuit to start heating.

Step 3, detecting whether the rectified power waveform reaches m0 time after the zero point t0, if not, continuing to execute the step 2; if yes, go to step 4. Specifically, the controller detects the current specific position of the rectified power waveform through the voltage sampling circuit. The value of m0 is preset according to the actual power, and the value range of t0 not more than m0 more than t1 is required to be met.

And 4, continuously outputting a pulse signal with the pulse width gradually increased to the driving circuit by the controller 8 until the time t1 after the zero point, wherein the output pulse width is increased to a target pulse width which can be preset to be N0.

Step 5, when the power waveform reaches m1 (m 1 is more than or equal to t1 and less than or equal to t2, and the value of m1 is preset according to the actual power) after t1, the controller 8 continuously outputs a pulse signal with the pulse width gradually reduced to the driving circuit, and outputs the pulse signal with the pulse width reduced to the target pulse width N1 until m2(t1 is more than or equal to m2 and less than or equal to t2, and the value of m2 is preset according to the actual power) before the peak value t 2;

step 6, when m3 (m 3 is more than or equal to t2 and less than t3, and m3 value is preset according to actual power) occurs after the power waveform reaches the peak value t2, the controller continuously outputs a pulse signal with the pulse width gradually increased to the driving circuit, and until t3, the pulse signal with the pulse width increased to a target pulse width N2(N2 may be equal to N0 or not equal to N0) is output;

step 7, when the power waveform reaches m4 (m 4 is more than or equal to t3 and less than or equal to t4, and the value of m4 is preset according to actual power) after t3, the controller continuously outputs pulse signals with the pulse width gradually reduced to the driving circuit, and the pulse signals with the pulse width reduced to the target pulse width N3 are output until m5(t3 is more than or equal to m5 and less than or equal to t4, and the value of m5 is preset according to actual power) is preset before the zero point t 4;

and 8, repeating the steps 1-6 when the power supply waveform reaches t 4.

Wherein, the starting point of the pulse width for changing the output of the controller can be the time t0, and the time t4 is finished as a period; the time period may be one cycle starting at a fixed time after the time t0 and ending at a fixed time before the time t 4. Wherein t0 and t4 are zero points of the rectified voltage waveform. Specifically, for the case of low heating power, the IGBT collector voltage is not as high relative to the high heating power, so m0 is preferably greater than t 0; m1 is preferably greater than t 1; that is, the output pulse width does not need to be adjusted immediately at the moment when the zero point is detected, and the adjustment principle of other parameters is similar to the adjustment principle.

In the above-described process of sequentially increasing and decreasing the pulse width, the pulse width to be increased or decreased may be fixed or may be variable.

If the controller outputs the pulse signal with the variable pulse width only in the first half cycle (t0-t2) of the rectified power waveform and outputs the pulse signal with the fixed pulse width in the second half cycle (t2-t4) of the rectified power waveform, the control method can only reduce the IGBT collector voltage before the peak value t2 and can not reduce the IGBT collector voltage after t2, so that the problems of high IGBT collector voltage and strong EMI interference can not be completely solved, as shown in FIG. 14.

If the controller outputs the pulse signal with the variable pulse width only in the second half cycle (t2-t4) of the rectified power waveform and outputs the pulse signal with the fixed pulse width in the first half cycle (t0-t2) of the rectified power waveform, the control method can only reduce the IGBT collector voltage after the peak value t2 and can not reduce the IGBT collector voltage before t2, so that the problems of high IGBT collector voltage and strong EMI interference can not be completely solved, as shown in FIG. 15.

In the method, the controller outputs the pulse signal with the variable pulse width in the whole period of the rectified power waveform, so that the voltage of the IGBT collector in the whole period can be reduced, and the problems of high voltage of the IGBT collector and strong EMI interference can be thoroughly solved.

The method reduces the collector voltage of the IGBT, can protect the IGBT from being burnt, reduces electromagnetic interference, enables EMI testing allowance to be sufficient, reduces EMI filtering devices, and reduces cost and the structure size of a Printed Circuit Board (PCB).

An embodiment of the present invention further provides an electronic device, as shown in fig. 16, where the electronic device includes a processor 130 and a memory 131, the memory 131 stores machine executable instructions that can be executed by the processor 130, and the processor 130 executes the machine executable instructions to implement the electromagnetic heating control method.

Further, the electronic device shown in fig. 16 further includes a bus 132 and a communication interface 133, and the processor 130, the communication interface 133, and the memory 131 are connected by the bus 132.

The Memory 131 may include a high-speed Random Access Memory (RAM) and may also include a non-volatile Memory (non-volatile Memory), such as at least one disk Memory. The communication connection between the network element of the system and at least one other network element is realized through at least one communication interface 133 (which may be wired or wireless), and the internet, a wide area network, a local network, a metropolitan area network, and the like can be used. The bus 132 may be an ISA bus, PCI bus, EISA bus, or the like. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, only one double-headed arrow is shown in FIG. 16, but that does not indicate only one bus or one type of bus.

The processor 130 may be an integrated circuit chip having signal processing capabilities. In implementation, the steps of the above method may be performed by integrated logic circuits of hardware or instructions in the form of software in the processor 130. The Processor 130 may be a general-purpose Processor, and includes a Central Processing Unit (CPU), a Network Processor (NP), and the like; the device can also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other Programmable logic devices, discrete Gate or transistor logic devices, discrete hardware components. The various methods, steps and logic blocks disclosed in the embodiments of the present invention may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of the method disclosed in connection with the embodiments of the present invention may be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The storage medium is located in the memory 131, and the processor 130 reads the information in the memory 131 and completes the steps of the method of the foregoing embodiment in combination with the hardware thereof.

The embodiment of the present invention further provides a machine-readable storage medium, where the machine-readable storage medium stores machine-executable instructions, and when the machine-executable instructions are called and executed by a processor, the machine-executable instructions cause the processor to implement the electromagnetic heating control method.

The electromagnetic heating control method, the electromagnetic heating control device, and the computer program product of the electromagnetic heating apparatus provided in the embodiments of the present invention include a computer-readable storage medium storing a program code, where instructions included in the program code may be used to execute the method described in the foregoing method embodiments, and specific implementations may refer to the method embodiments and are not described herein again.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, an electronic device, or a network device) to perform all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

Finally, it should be noted that: the above-mentioned embodiments are only specific embodiments of the present invention, which are used for illustrating the technical solutions of the present invention and not for limiting the same, and the protection scope of the present invention is not limited thereto, although the present invention is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: any person skilled in the art can modify or easily conceive the technical solutions described in the foregoing embodiments or equivalent substitutes for some technical features within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the embodiments of the present invention, and they should be construed as being included therein. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.