WO2022143642A1

WO2022143642A1 - Electromagnetic heating apparatus, and power control method and power control device therefor

Info

Publication number: WO2022143642A1
Application number: PCT/CN2021/142002
Authority: WO
Inventors: 曾露添; 朱成彬; 雷俊; 江德勇; 刘文华; 王云峰
Original assignee: 佛山市顺德区美的电热电器制造有限公司
Priority date: 2020-12-29
Filing date: 2021-12-28
Publication date: 2022-07-07

Abstract

An electromagnetic heating apparatus, and a power control method and power control device therefor. The power control method for an electromagnetic heating apparatus comprises the following steps: when it is determined that a plurality of heating modules (50) of the electromagnetic heating apparatus operate at the same time, acquiring the input power of each heating module (50), and when the input power of the plurality of heating modules (50) is different, determining the types of corresponding heating modules (50) according to the input power of each heating module (50); and controlling, according to the type of each heating module (50), the output power of the corresponding heating modules (50) by using different power adjustment manners.

Description

Electromagnetic heating equipment, power control method and power control device thereof

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of the Chinese patent application numbers "202011591759.3", "202011589013.9", "202011591745.1" and "202011593049.4" filed by Midea Electric Heating Appliance Manufacturing Co., Ltd., Shunde District, Foshan City on December 29, 2020. The entire contents of the application are incorporated herein by reference.

technical field

The present application relates to the technical field of electromagnetic heating equipment, and more particularly, to an electromagnetic heating equipment, a power control method thereof, and a power control device.

Background technique

In the related art, the output power adjustment of the furnace heads is usually realized by the same adjustment method. As a result, when multiple furnace heads are heated at the same time, the operating frequencies of each furnace head are usually inconsistent, and the mixing of multiple frequencies will generate a series of synthetic frequencies. , in which the synthesized difference frequency signal will produce sharp and harsh noise, which is often unacceptable to the user and greatly reduces the user experience.

For example, in some related technologies, the output power is controlled by adjusting the working frequency of the burners, so that when multiple burners are heated at the same time, since the power required by each burner is different, the working frequency of each burner is also different. the same, producing louder noise.

SUMMARY OF THE INVENTION

The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a power control method for an electromagnetic heating device, which is conducive to realizing the frequency consistency of a plurality of heating modules working at the same time, thereby helping to reduce the noise caused by the difference frequency.

The present application also proposes a computer-readable storage medium.

The present application also proposes an electromagnetic heating device capable of implementing the above power control method.

The present application also proposes a power control device for an electromagnetic heating device.

In order to achieve the above purpose, an embodiment of the present application proposes a power control method for an electromagnetic heating device, including the following steps: when it is determined that multiple heating modules of the electromagnetic heating device are working simultaneously, acquiring the input power of each heating module , and when the input power of the plurality of heating modules is different, the type of the corresponding heating module is determined according to the input power of each heating module; according to the type of each heating module, different power adjustment methods are used to adjust the corresponding heating module. output power is controlled.

According to the power control method of the electromagnetic heating device according to the embodiment of the present application, by using different power adjustment methods for different types of heating modules to control the output power, it is beneficial to realize the frequency consistency of multiple heating modules working at the same time, thereby avoiding the need for work In the process, multiple frequencies are mixed together to generate a synthetic frequency, so as to avoid the sharp and harsh noise caused by the synthetic difference frequency signal, which is beneficial to improve the user's experience.

In addition, the power control method of the electromagnetic heating device according to the above embodiments of the present application may also have the following additional technical features:

According to some embodiments of the present application, the types of the heating modules include a master heating module and a slave heating module, wherein determining the type of the corresponding heating module according to the input power of each heating module includes: acquiring the plurality of heating modules The heating module with the largest input power among the heating modules, and the heating module with the largest input power is used as the main heating module, and the remaining heating modules among the plurality of heating modules are used as the slave heating modules.

According to some embodiments of the present application, according to the type of each heating module, different power adjustment methods are used to control the output power of the corresponding heating module, including: when it is determined that the current heating module is the main heating module, using a frequency modulation power adjustment method The output power of the main heating module is controlled; when it is determined that the current heating module is the slave heating module, the output power of the slave heating module is controlled by a power adjustment method of adjusting the duty ratio.

According to some embodiments of the present application, controlling the output power of the main heating module by means of frequency modulation power regulation includes: outputting a first PWM signal with a fixed duty cycle to the main heating module, and adjusting the first PWM signal with a fixed duty cycle to the main heating module. The frequency of a PWM signal to control the output power of the main heating module.

According to some embodiments of the present application, controlling the output power of the slave heating module in a power adjustment manner of adjusting the duty cycle includes: outputting a second PWM signal of a fixed frequency to the slave heating module, and adjusting the The duty cycle of the second PWM signal is used to control the output power of the slave heating module.

According to some embodiments of the present application, the frequency of the second PWM signal is the same as the frequency of the first PWM signal.

According to some embodiments of the present application, the fixed duty cycle is 50%, and the duty cycle of the second PWM signal is adjustable from 0 to 50%.

According to some embodiments of the present application, when it is determined that the electromagnetic heating device has only one heating module to work, the output power of the heating module is controlled by means of frequency modulation power regulation.

According to some embodiments of the present application, the power control method includes the following steps: when the output power of the slave heating module of the electromagnetic heating device is controlled in a power adjustment manner of adjusting the duty ratio, determining to drive the slave heating module to perform The current duty cycle adjustment mode of the heating work; when it is determined that the current duty cycle adjustment mode for driving the slave heating module to perform the heating work is the complementary duty cycle continuous adjustment mode, determine whether the upper bridge switch tube of the slave heating module is Works in a hard-on state; if the upper bridge switch tube of the slave heating module works in a hard turn-on state, the complementary duty cycle-symmetric duty cycle alternate heating control method is used to control the upper bridge switch tube of the slave heating module. Controlled by the lower bridge switch.

According to some embodiments of the present application, judging whether the upper bridge switch tube of the slave heating module works in a hard-on state includes: judging whether the duty cycle of the PWM signal of the upper bridge switch tube is less than a preset value; if the If the duty cycle of the PWM signal of the upper-bridge switch tube is smaller than the preset value, it is determined that the upper-bridge switch tube is in a hard-on state.

According to some embodiments of the present application, judging whether the upper bridge switch tube of the slave heating module works in a hard-on state includes: detecting the midpoint voltage between the upper bridge switch tube and the lower bridge switch tube of the slave heating module; According to the midpoint voltage, it is determined whether the voltage difference between the collector and the emitter of the upper-bridge switch is greater than a preset voltage threshold; the voltage difference between the collector and the emitter of the upper-bridge switch is greater than When the voltage threshold is preset, it is determined that the upper-bridge switch tube works in a hard-on state.

According to some embodiments of the present application, controlling the upper-bridge switch tube and the lower-bridge switch tube of the slave heating module by adopting a complementary duty cycle-symmetric duty cycle alternate heating control method includes: controlling the electromagnetic heating device. Input the zero-crossing point of the AC power supply for counting; determine whether the zero-crossing point count value is an odd value; when the zero-crossing point count value is an odd value, output a PWM signal with a symmetrical duty cycle to the upper bridge switch tube and the lower A bridge switch tube, so that the slave heating module performs heating work; when the zero-crossing point count value is an even value, a PWM signal with a complementary duty cycle is output to the upper bridge switch tube and the lower bridge switch tube, In order to make the heating work from the heating module.

According to some embodiments of the present application, the complementary duty cycle refers to the electrical level of the PWM signal of the upper-bridge switch tube and the voltage level of the PWM signal of the lower-bridge switch tube in one PWM cycle, excluding dead time. The level is inverse relationship to each other; the symmetrical duty cycle means that in one PWM cycle, the level of the PWM signal of the upper bridge switch tube and the level of the PWM signal of the lower bridge switch tube are in an inverse relationship to each other, And the conduction time of the upper bridge switch is equal to the conduction time of the lower bridge switch.

According to some embodiments of the present application, the power control method includes the following steps: when a plurality of heating modules of the electromagnetic heating device are working at the same time, determining a slave heating module in the plurality of heating modules; adjusting the duty cycle control the output power of the slave heating module and determine whether the upper bridge switch tube of the slave heating module works in a hard-on state; if the upper bridge switch tube of the slave heating module works in a hard-on state state, the upper bridge switch tube and the lower bridge switch tube of the slave heating module are controlled by an alternate duty cycle heating control method.

According to some embodiments of the present application, determining whether the upper bridge switch tube of the slave heating module works in a hard-on state includes: judging whether the duty cycle of the PWM signal of the upper bridge switch tube is less than a preset value; if the If the duty cycle of the PWM signal of the upper-bridge switch tube is smaller than the preset value, it is determined that the upper-bridge switch tube is in a hard-on state.

According to some embodiments of the present application, determining whether the upper bridge switch tube of the slave heating module works in a hard-on state includes: detecting a midpoint voltage between the upper bridge switch tube and the lower bridge switch tube of the slave heating module; Determine whether the voltage difference between the collector and the emitter of the upper-bridge switch is greater than a preset voltage threshold according to the midpoint voltage; the voltage difference between the collector and the emitter of the upper-bridge switch is greater than When the voltage threshold is preset, it is determined that the upper-bridge switch tube works in a hard-on state.

According to some embodiments of the present application, using an alternate duty cycle heating control method to control the upper bridge switch tube and the lower bridge switch tube of the slave heating module includes: controlling the zero-crossing point of the input AC power supply of the electromagnetic heating device. Count; determine whether the zero-crossing count value is an odd value; when the zero-crossing count value is an odd value, output a PWM signal with a forward duty cycle to the upper-bridge switch tube and the lower-bridge switch tube, so that the The slave heating module performs heating work; when the zero-crossing point count value is an even value, output a PWM signal with a reverse duty cycle to the upper bridge switch tube and the lower bridge switch tube, so that the slave The heating module performs heating work.

According to some embodiments of the present application, when the duty cycle of the PWM signal output to the upper-bridge switch is in the range of 0-50%, it is the forward duty cycle, and the PWM signal output to the upper-bridge switch is in the range of 0-50%. When the duty cycle is in the range of 51-100%, it is the reverse duty cycle.

According to some embodiments of the present application, the power control method includes the following steps: when a plurality of heating modules of the electromagnetic heating device are working at the same time, determining a slave heating module in the plurality of heating modules; adjusting the duty cycle control the output power of the slave heating module and determine whether the upper bridge switch tube of the slave heating module works in a hard-on state; if the upper bridge switch tube of the slave heating module works in a hard-on state In the state, the lost-wave heating control method is used to control the upper bridge switch tube.

According to some embodiments of the present application, using the lost-wave heating control method to control the upper bridge switch tube includes: counting the zero-crossing points of the input AC power supply of the electromagnetic heating device; determining whether the zero-crossing point count value is greater than a preset value Loss wave threshold; when the zero-crossing count value is greater than the preset lost-wave threshold, output a PWM signal to the upper bridge switch tube to enable the slave heating module to perform heating; when the zero-crossing count value is less than or equal to When the wave loss threshold is preset, the output PWM signal to the upper bridge switch is turned off, so that the slave heating module stops heating.

In order to achieve the above purpose, an embodiment of the present application proposes a computer-readable storage medium on which a power control program of an electromagnetic heating device is stored. The described power control method of electromagnetic heating equipment.

In order to achieve the above purpose, an embodiment of the present application proposes an electromagnetic heating device, which includes a memory, a processor, and a power control program for the electromagnetic heating device that is stored in the memory and can be run on the processor, and the processor executes the power control program. When controlling the program, the power control method of the electromagnetic heating device as described in the embodiments of the present application is implemented.

In order to achieve the above purpose, an embodiment of the present application proposes a power control device for an electromagnetic heating device, comprising: a determination module for obtaining the power of each heating module when it is determined that multiple heating modules of the electromagnetic heating device are working at the same time. input power, and determine the type of the corresponding heating module according to the input power of each heating module when the input power of the plurality of heating modules is different; the power control module is used to use different heating modules according to the type of each heating module. The output power of the corresponding heating module is controlled by the power adjustment method.

According to the power control device of the electromagnetic heating device according to the embodiment of the present application, by using different power adjustment methods for different types of heating modules to control the output power, it is beneficial to realize the frequency consistency of multiple heating modules working at the same time, thereby avoiding the need for work In the process, multiple frequencies are mixed together to generate a synthetic frequency, so as to avoid the sharp and harsh noise caused by the synthetic difference frequency signal, which is beneficial to improve the user's experience.

Additional aspects and advantages of the present application will be set forth, in part, from the following description, and in part will become apparent from the following description, or may be learned by practice of the present application.

Description of drawings

The above and/or additional aspects and advantages of the present application will become apparent and readily understood from the following description of embodiments in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic diagram of a power control apparatus according to some embodiments of the present application;

2 is a schematic flowchart of a power control method for an electromagnetic heating device according to some embodiments of the present application;

3 is a schematic flowchart of step S1 of a power control method according to a specific embodiment of the present application;

4 is a schematic diagram of a power control device and a heating module according to a specific embodiment of the present application;

5 is a graph showing the relationship between the PWM frequency and the output power of the main heating module according to an embodiment of the present application;

6 is a flow chart of controlling the output power of the main heating module by adopting a frequency modulation power adjustment method according to an embodiment of the present application;

7 is a PWM waveform diagram of the output main heating module of the power control device according to an embodiment of the present application;

Fig. 8 is according to the situation that the half-bridge switch tube PWM frequency of the heating module is equal to the main heating module according to the embodiment of the present application, from the duty ratio of the heating module and the relationship diagram of the output power;

9 is a flow chart of controlling the output power of the slave heating module according to an embodiment of the present application using a power adjustment method of adjusting the duty ratio;

10 is a PWM waveform diagram of a power control device outputting a master heating module and a slave heating module according to an embodiment of the present application;

FIG. 11 is a schematic diagram of a power control apparatus according to other embodiments of the present application;

12 is a schematic flowchart of a power control method for an electromagnetic heating device according to other embodiments of the present application;

13 is a schematic diagram of a power control device and a heating module according to another specific embodiment of the present application;

14 is a working waveform diagram of a slave heating module according to an embodiment of the present application;

15 is a working waveform diagram corresponding to a continuous heating control mode and a lost-wave heating control mode according to an embodiment of the present application;

16 is a flow chart of controlling the upper bridge switch tube by adopting the lost-wave heating control mode according to a specific embodiment of the present application;

17 is a schematic flowchart of a power control method for an electromagnetic heating device according to other embodiments of the present application;

18 is a working waveform diagram of a 50% duty cycle and a 20% duty cycle switch tube according to an embodiment of the present application;

FIG. 19 is a working waveform diagram corresponding to a complementary duty cycle continuous adjustment mode and a complementary duty cycle-symmetrical duty cycle alternate heating control mode according to an embodiment of the present application;

20 is a working waveform diagram of outputting a PWM signal with a complementary duty cycle and a PWM signal with a symmetrical duty cycle to a switch tube according to an embodiment of the present application;

21 is a flow chart of controlling the upper-bridge switch tube and the lower-bridge switch tube by using a complementary duty cycle-symmetric duty cycle alternate heating control method according to a specific embodiment of the present application;

22 is a schematic flowchart of a power control method for an electromagnetic heating device according to other embodiments of the present application;

FIG. 23 is a working waveform diagram of the 50% duty cycle and 20% duty cycle switch tubes according to an embodiment of the present application;

24 is a working waveform diagram corresponding to a continuous duty cycle control mode and an alternate duty cycle heating control mode according to an embodiment of the present application;

25 is a working waveform diagram of outputting a PWM signal of a forward duty cycle and a PWM signal of a reverse duty cycle to a switch tube according to an embodiment of the present application;

FIG. 26 is a flow chart of controlling the upper bridge switch tube and the lower bridge switch tube by adopting an alternate duty cycle heating control method according to a specific embodiment of the present application.

Description of drawings:

power control device 100; heating module 50;

determination module 10; power control module 20; first determination module 30; second determination module 40;

The first heating module 200; the first driving module 201; the first upper bridge switch tube 202; the first lower bridge switch tube 203; the first heating coil 204; the first pair of

resonant capacitors

205, 206; detection module 207;

The second heating module 300; the second driving module 301; the second upper bridge switch tube 302; the second lower bridge switch tube 303; the second heating coil 304; the second

resonant capacitor pair

305, 306; detection module 307;

Zero-crossing detection module 101 .

Detailed ways

The following describes in detail the embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, and are intended to be used to explain the present application, but should not be construed as a limitation to the present application.

The electromagnetic heating device, its power control method, and the power control device 100 according to the embodiments of the present application will be described below with reference to the accompanying drawings.

Multiple heating modules 50 of the electromagnetic heating device (the number of heating modules 50 is two or more) can correspond to multiple heating zones, and multiple heating zones can be used for heating multiple appliances to simultaneously perform multiple cooking processes . The electromagnetic heating device here may be a multi-head induction cooker or the like, and the heating module 50 may include a heating coil and the like.

The following describes a power control method for an electromagnetic heating apparatus according to an embodiment of the present application and a power control apparatus 100 for an electromagnetic heating apparatus according to an embodiment of the present application with reference to FIGS. 1 to 10 .

As shown in FIG. 1 , the power control device 100 of the electromagnetic heating device includes: a determination module 10 and a power control module 20 . Wherein, the determining module 10 is configured to obtain the input power of each heating module 50 when it is determined that multiple heating modules 50 of the electromagnetic heating device are working at the same time, and when the input power of the multiple heating modules 50 is different, according to each heating module 50 The input power of the module 50 determines the type of the corresponding heating module 50 ; the power control module 20 is used to control the output power of the corresponding heating module 50 by using different power adjustment methods according to the type of each heating module 50 .

As shown in Fig. 2, the power control method of the electromagnetic heating device includes step S1 and step S2.

Step S1: When it is determined that multiple heating modules 50 of the electromagnetic heating device are working simultaneously, the input power of each heating module 50 is obtained, and when the input power of the multiple heating modules 50 is different, according to the input power of each heating module 50 The power determination corresponds to the type of heating module 50 .

For example, in some embodiments, the types of heating modules 50 include master heating modules and slave heating modules. Determining the type of the corresponding heating module 50 according to the input power of each heating module 50 may include: acquiring the heating module 50 with the largest input power among the plurality of heating modules 50, and using the heating module 50 with the largest input power as the main heating module, and The remaining heating modules 50 among the plurality of heating modules 50 are used as slave heating modules. Thus, the heating modules 50 are classified according to different input powers, wherein the input power may be the power input by the user to each heating module 50 according to the desired cooking function. Here, the number of slave heating modules is one or more than one. When only one heating module 50 of the electromagnetic heating device works, the heating module 50 can be used as the main heating module or the secondary heating module to control the output power by using a corresponding power adjustment method.

In a specific embodiment according to the present application, as shown in FIG. 3 , in step S1, the type of the corresponding heating module 50 is determined according to the input power of each heating module 50, including step S11 and step S12, and the details are as follows:

Step S11: Determine whether the input power of any one of the heating modules 50 has changed. If not, there is no need to judge the type of the heating module 50 and control the output power, exit the method, and keep the current output power of the heating module 50; if yes, execute step S12.

Step S12 : Obtain the heating module 50 with the largest input power among the plurality of heating modules 50 , use the heating module 50 as the master heating module, and use the remaining heating modules 50 among the plurality of heating modules 50 as the slave heating modules.

From this, the type of heating module 50 is determined.

As shown in FIG. 2 , step S2 : according to the type of each heating module 50 , different power adjustment methods are used to control the output power of the corresponding heating module 50 . Therefore, the output power of each heating module 50 is equal to its corresponding input power.

By using different power adjustment methods for different types of heating modules 50 to control the output power, it is beneficial to realize the consistency of the operating frequencies of a plurality of heating modules 50 working at the same time, thereby avoiding the mixing of multiple frequencies during the working process to produce a series of It avoids the sharp and harsh noise caused by the synthesis of the difference frequency signal, which is beneficial to improve the user experience.

For example, in some embodiments, step S2: according to the type of each heating module 50, using different power adjustment methods to control the output power of the corresponding heating module 50, including steps S21 and S22.

Step S21 : when it is determined that the current heating module 50 is the main heating module, the output power of the main heating module is controlled by adopting a power adjustment method of frequency modulation.

The power control device 100 of the electromagnetic heating device outputs a PWM (Pulse Width Modulation) signal to control a plurality of heating modules 50, and the plurality of heating modules 50 are respectively a first heating module 200, a second heating module 300, and a third heating module 50...wherein, as shown in FIG. 4, the first heating module 200 includes a first driving module 201, a first upper bridge switch tube 202, a first lower bridge switch tube 203, a first heating coil 204 and a first pair of resonant capacitors 205, 206; the second heating module 300 includes a second driving module 301, a second upper bridge switch tube 302, a second lower bridge switch tube 303, a second heating coil 304, and a second pair of resonant capacitors 305, 306; ... electromagnetic The power control device 100 of the heating equipment outputs a PWM signal to the drive module, and the drive module outputs a complementary PWM signal to control the upper bridge switch tube and the lower bridge switch tube to be turned on alternately, and to control the heating coil to output an alternating current to generate an alternating magnetic field, alternating The magnetic field induces alternating eddy currents in the metal pot placed on the heating coil, and the alternating eddy current causes the pot to heat up, thereby heating food.

The output power of the main heating module is controlled by the power regulation method of frequency modulation. The specific principles are as follows:

Figure 5 shows the relationship between the PWM frequency and the output power of the main heating module. In the frequency range of the inductive region (frequency f0 ~ f1), the larger the PWM frequency, the smaller the output power; the smaller the PWM frequency, the lower the output power. big.

Figure 6 is a flow chart of controlling the output power of the main heating module by adopting the power regulation method of frequency modulation. Specifically include the following steps:

Step S211: Determine whether the input power of the main heating module increases, if so, go to Step S212; if not, go to Step S214;

Step S212: reduce the PWM frequency of the main heating module, and then perform step S213;

Step S213: judge whether the output power of the current main heating module is equal to the input power, if so, the output power control of the main heating module ends, and exit this method; if not, return to execute S212;

Step S214: increase the PWM frequency of the main heating module, and then execute step S215;

Step S215: Determine whether the current output power of the main heating module is equal to the input power, if so, the output power control of the main heating module ends, and the method is exited; if not, return to S214.

As shown in FIG. 7 , the power control device 100 outputs a PWM waveform diagram of the main heating module. The power control device 100 outputs the PWM waveform of the main heating module as W10 in Figure 7, the output power is 1000W (corresponding to P10 in Figure 5), and the frequency is corresponding to 25KHz (corresponding to f10 in Figure 5).

If the user adjusts the thermal power to increase to 1500W, that is, adjusts the input power of the main heating module to 1500W, then execute steps S212 and S213 until the output power of the main heating module is equal to the input power, then the power control device 100 outputs the PWM waveform of the main heating module. The waveform of W11 in Figure 7, the output power is shown in P11 (1500W) in Figure 5, and the corresponding PWM frequency is shown in f11 (23KHz) in Figure 5. It can be seen that the frequency of the output PWM of the power control device 100 is reduced from 25KHz (f10) to 23KHz (f11), and the output power is increased from 1000W to 1500W.

If the user adjusts the thermal power to be reduced to 500W, that is, adjusts the input power of the main heating module to 500W, then execute steps S214 and S215 until the output power of the main heating module is equal to the input power, then the power control device 100 outputs the main heating module PWM waveform such as In the waveform of W12 in Figure 7, the output power is shown as P12 (500W) in Figure 5, and the corresponding PWM frequency is shown as f12 (27KHz) in Figure 5. It can be seen that the frequency of the output PWM of the power control device 100 is increased from 25KHz (f10) to 27KHz (f12), and the output power is reduced from 1000W to 500W.

The output power of the main heating module is controlled by the power adjustment method of frequency modulation, so that the output power of the main heating module can be adjusted more quickly, and can be quickly adjusted to be equal to the input power, which improves the user experience. And it is beneficial to obtain a larger working power and meet a larger range of adjusting the output power.

Step S22 : when it is determined that the current heating module 50 is the slave heating module, the output power of the slave heating module is controlled by adopting a power adjustment method of adjusting the duty ratio.

The specific principle of controlling the output power from the heating module by using the power adjustment method of adjusting the duty cycle is as follows:

Figure 8 shows the relationship between the duty cycle of the slave heating module and the output power when the PWM frequency of the half-bridge switch tube of the slave heating module is equal to that of the master heating module. It can be seen that the smaller the duty cycle of PWM, the smaller the output power; the larger the duty cycle of PWM, the greater the output power.

Fig. 9 is a flow chart of controlling the output power of the slave heating module by adopting the power adjustment method of adjusting the duty ratio. Specifically include the following steps:

Step S221: Determine whether the input power from the heating module increases, if yes, go to Step S222; if not, go to Step S224;

Step S222: increase the PWM duty ratio of the slave heating module, and then execute step S223;

Step S223: determine whether the current output power of the heating module is equal to the input power, if so, the output power control of the heating module is terminated, and the method is exited; if not, return to execute S222;

Step S224: reduce the PWM duty cycle of the slave heating module, and then perform step S225;

Step S225: Determine whether the current output power of the slave heating module is equal to the input power, if so, the output power control of the slave heating module ends, and the method is exited; if not, return to S224.

As shown in FIG. 10 , the power control device 100 outputs a PWM waveform diagram of the master heating module and the slave heating module. Wherein, W20 is the PWM waveform of the main heating module output by the power control device 100, and the duty ratio is 50%. The waveform W21 is the PWM waveform output by the power control device 100 from the heating module, and the duty cycle is 30% (corresponding to P20 in Figure 8). The PWM cycle of the module (T20 in Fig. 1) is equal, obtained from the formula frequency f=1/T, the PWM frequency of the slave heating module is the same as the PWM frequency of the main heating module.

If the user adjusts the heating power of the slave heating module to increase from 500W to 600W, that is, adjusts the input power of the slave heating module to 600W, then execute steps S222 and S223 until the output power of the slave heating module is equal to the input power, the power control device 100 outputs the output power of the slave heating module to 600W. The waveform of the module PWM is the waveform of W22 in Figure 10. At this time, the high level time of the heating module PWM is increased from t21 in Figure 10 to t22, and the corresponding duty cycle is increased from 30% in Figure 8 to 40%. The output power is increased from 500W to 600W.

If the user adjusts the heating power of the slave heating module to be reduced from 500W to 400W, that is, adjusts the input power of the slave heating module to 400W, then steps S224 and S225 are performed until the output power of the slave heating module is equal to the input power, and the power control device 100 outputs the output power of the slave heating module. The waveform of PWM is the waveform of W23 in Figure 10. At this time, the PWM high level time from the heating module is reduced from t21 in Figure 10 to t23, and the corresponding duty cycle is reduced from 30% in Figure 8 to 30% to achieve output power. Reduced from 500W to 400W.

The output power of the slave heating module is controlled by the power adjustment method of adjusting the duty ratio, so that the PWM frequency of the slave heating module remains unchanged during the power adjustment process, which is beneficial to realize the PWM frequency of the main heating module and the slave heating module. Consistency, and the consistency of the PWM frequencies of multiple slave heating modules, no matter how the output power of the master heating module and the slave heating modules changes, the power control device 100 outputs the PWM frequency of the master heating module and the PWM frequency of the slave heating modules to remain the same , that is, the frequency difference of all output PWMs remains zero. Since the difference frequency signal is zero, there is no sharp and harsh noise, which effectively improves the user experience.

According to the power control method of the electromagnetic heating device according to some embodiments of the present application, by using different power adjustment methods for different types of heating modules 50 to control the output power, it is beneficial to realize the frequency consistency of multiple heating modules 50 working at the same time, Thereby, multiple frequencies are mixed together to generate synthetic frequencies during the working process, and sharp and harsh noises caused by synthetic difference frequency signals are avoided, which is beneficial to improve the user experience.

According to the power control device 100 of an electromagnetic heating device according to some embodiments of the present application, by using different power adjustment methods for different types of heating modules 50 to control the output power, it is beneficial to realize the frequency consistency of multiple heating modules 50 working at the same time , so as to avoid the mixing of multiple frequencies in the working process to generate a synthetic frequency, and avoid the sharp and harsh noise generated by the synthesis of the difference frequency signal, which is beneficial to improve the user experience.

In some embodiments of the present application, the method for determining the type of the corresponding heating module 50 by the determination module 10 and the method for the power control module 20 to control the output power of the corresponding heating module 50 by using different power adjustment methods may refer to the embodiments of the present application The power control method of the electromagnetic heating device is not repeated here.

According to some embodiments of the present application, step S21 : controlling the output power of the main heating module by adopting a frequency modulation power adjustment method, including: outputting a first PWM signal with a fixed duty cycle to the main heating module, and adjusting the first PWM signal by adjusting the first PWM signal. The frequency of the signal to control the output power of the main heating module. As shown in FIG. 5 , when the duty cycle of the first PWM signal is constant, the higher the frequency, the lower the output power, and the lower the frequency, the higher the output power. By fixing the duty ratio of the first PWM signal and only adjusting the frequency of the first PWM signal to adjust the output power of the main heating module, the power adjustment is made faster and the power adjustment method is simplified.

In addition, step S22 : controlling the output power of the slave heating module by using a power adjustment method of adjusting the duty ratio, including: outputting a second PWM signal of a fixed frequency to the slave heating module, and adjusting the duty ratio of the second PWM signal to control the output power from the heating module. As shown in FIG. 8 , when the frequency of the second PWM signal is constant, the larger the duty cycle, the greater the output power, and the smaller the duty cycle, the lower the output power. By fixing the frequency of the second PWM signal and only adjusting the duty ratio of the second PWM signal to adjust the output power of the slave heating modules, the frequencies of multiple slave heating modules are always equal, effectively reducing the generation of difference frequency signals.

Also, in some embodiments, the frequency of the second PWM signal is the same as the frequency of the first PWM signal. In other words, the frequencies of the master heating module and the slave heating module are always equal, thereby effectively avoiding the generation of the difference frequency signal. For example, in some specific embodiments, after the frequency of the first PWM signal is adjusted so that the output power of the main heating module is equal to the input power, the frequency of the second PWM signal is controlled to be equal to the frequency of the first PWM signal after adjustment, and then the second PWM signal is controlled to be equal to the frequency of the first PWM signal after adjustment. The duty cycle of the signal is adjusted so that the output power of the slave heating module is equal to the input power, so as to achieve frequency consistency between the master heating module and the slave heating module. Moreover, in the embodiment in which there are multiple slave heating modules, the output powers of the multiple slave heating modules can be controlled independently without interfering with each other, and the frequency consistency can be well maintained, and the power adjustment method is simpler.

In some embodiments, the fixed duty cycle of the first PWM signal is 50%, and the duty cycle of the second PWM signal is adjustable from 0 to 50%, so that the output power of the slave heating module is less than or equal to that of the master heating module can be adjusted within the range of the output power. For example, in some embodiments, the duty cycle of the second PWM signal can be adjusted to 0, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, and 50% Wait. Wherein, when the duty cycle of the second PWM signal is 0, the slave heating module stops heating; when the duty cycle of the second PWM signal is 50%, the output power of the slave heating module is equal to the output power of the main heating module.

It should be noted that, when there are two or more heating modules 50 with the largest input power among the plurality of heating modules 50, one of the heating modules 50 with the largest input power can be used as the main heating module, and the remaining heating modules 50 can be used as the main heating module. As a slave heating module; alternatively, all the heating modules 50 with the maximum input power and equal input power can be used as the master heating module, and other heating modules 50 except a few master heating modules can be used as slave heating modules to control these several heating modules. The main heating module inputs the first PWM signal with the same fixed duty cycle.

According to some embodiments of the present application, when it is determined that the electromagnetic heating device has only one heating module 50 to work, the output power of the heating module 50 is controlled by using a power adjustment method of frequency modulation, so that the output power control of the heating module 50 is more efficient. Fast and able to output a wider range or higher output power to meet cooking needs.

For example, in a specific embodiment, when it is determined that the electromagnetic heating device has only one heating module 50 to work, the heating module 50 is controlled to input a first PWM signal with a fixed duty cycle of 50%, and adjust the first PWM signal by adjusting the first PWM signal. frequency to control the output power of the heating module 50 .

In addition, the applicant found that when the duty cycle of the heating module 50 is less than a certain value, the switchable transistor of the upper bridge of the half-bridge will enter a hard-on state from a soft-on state, and the loss and temperature of the switch tube will increase, which will lead to damage to the switch tube. , the reliability of electromagnetic heating equipment is reduced. Based on this, the present application also proposes a power control method and a power control device 100 that can prevent a switch tube from entering a hard-on state.

As shown in FIG. 11 , a power control apparatus 100 for an electromagnetic heating device according to some embodiments of the present application may include: a first determination module 30 , a power control module 20 and a second determination module 40 .

Wherein, the first determination module 30 is used to determine the slave heating module among the plurality of heating modules 50 when the plurality of heating modules 50 of the electromagnetic heating device are working at the same time, and its function is equivalent to the power control device according to the previous embodiment of the present application The determination module 10 of 100 . The power control module 20 is used to control the output power from the heating module by adopting a power regulation method of adjusting the duty ratio. The second determination module 40 is configured to determine whether the upper bridge switch tube of the slave heating module works in a hard-on state when the power control module 20 controls the output power of the slave heating module by using a power adjustment method of adjusting the duty ratio. In addition, the power control module 20 is also used to control the upper bridge switch tube by using the lost wave heating control method when the upper bridge switch tube of the slave heating module works in a hard-on state.

As shown in FIG. 12 , the power control method for an electromagnetic heating device according to some embodiments of the present application may include steps S123 , S124 and S125 . details as follows:

Step S123 : when the plurality of heating modules 50 of the electromagnetic heating device are working at the same time, determine the slave heating module among the plurality of heating modules 50 .

The slave heating module may be a heating module 50 with a non-maximal input power among the plurality of heating modules 50 , in other words, the slave heating module may be a heating module 50 with a relatively small input power among the plurality of heating modules 50 . For example, for the method of determining the slave heating module among the plurality of heating modules 50, reference may be made to the foregoing description of the power control method of the electromagnetic heating device, and its specific content and beneficial effects will not be repeated here.

Step S124 : control the output power of the slave heating module by using a power adjustment method of adjusting the duty ratio, and determine whether the upper bridge switch tube of the slave heating module works in a hard-on state.

The switch tube has low loss and low temperature rise in the soft-on state, which is an ideal working state. When the switch tube is in a hard-on state, the loss is large and the temperature rises. Under normal circumstances, when the duty cycle of the PWM signal is greater than a certain value, the upper bridge switch tube and the lower bridge switch tube work in a soft-on state. However, when the duty cycle is less than a certain value, the upper-bridge switch tube will enter a hard-on state from a soft-on state. Therefore, it is determined whether the upper bridge switch tube of the slave heating module is working in a hard-on state, and control is performed accordingly to avoid excessive loss and high temperature rise of the upper bridge switch tube.

For example, in some embodiments, step S124: determining whether the upper bridge switch of the slave heating module works in a hard-on state, which may include steps S1241 and S1242, as follows:

Step S1241: Determine whether the duty cycle of the PWM signal of the upper bridge switch is less than a preset value.

Step S1242 : if the duty cycle of the PWM signal of the upper-bridge switch is smaller than the preset value, it is determined that the upper-bridge switch is in a hard-on state.

Here, the preset value can be flexibly set according to the actual situation. For example, in some specific embodiments, the preset value can be 30%. If the duty cycle of the PWM signal of the upper bridge switch is 20%, 20% is less than 30%. , make sure that the upper bridge switch is in the hard-on state.

For another example, in some embodiments, step S124: determining whether the upper bridge switch tube of the slave heating module works in a hard-on state, which may include steps S1243, S1244 and S1245, as follows:

Step S1243: Detect the midpoint voltage between the upper bridge switch tube and the lower bridge switch tube of the slave heating module;

Step S1244: Determine whether the voltage difference between the collector and the emitter of the upper bridge switch is greater than a preset voltage threshold according to the midpoint voltage;

Step S1245: When the voltage difference between the collector and the emitter of the upper-bridge switch is greater than the preset voltage threshold, it is determined that the upper-bridge switch is in a hard-on state.

Here, the preset voltage threshold may be set according to the actual situation, for example, the preset voltage threshold may be 0V. When the switch is turned on, if the voltage difference between the collector and the emitter of the switch is less than or equal to 0V, it is called a soft-on state. On the contrary, if the voltage difference between the collector and the emitter of the switch is greater than 0V, it is called a hard-on state.

The power control device 100 of the electromagnetic heating device outputs a PWM signal to control a plurality of heating modules 50 . The plurality of heating modules 50 are respectively the first heating module 200 and the second heating module 300 . A correspondingly arranged first half-bridge mid-point voltage detection module 207 , second half-bridge mid-point voltage detection module 307 . . .

Wherein, as shown in FIG. 13 , the first heating module 200 includes a first driving module 201 , a first upper bridge switch tube 202 , a first lower bridge switch tube 203 , a first heating coil 204 and a first pair of

resonant capacitors

205 and 206 , the first half-bridge mid-point voltage detection module 207 is used to detect whether the first high-bridge switch tube 202 is in a hard-on state or a soft-on state; the second heating module 300 includes a second drive module 301, a second high-bridge switch tube 302 , the second lower bridge switch tube 303, the second heating coil 304 and the second

resonant capacitor pair

305, 306, the second half-bridge mid-point voltage detection module 307 is used to detect whether the second upper bridge switch tube 302 is in a hard-on state or not Soft-on state; …

The following description will be given by taking the second heating module 300 as the slave heating module as an example.

FIG. 14 is a working waveform diagram of the second heating module 300 . W10 is the gate (g1) driving waveform of the second high-bridge switch 302, W11 is the gate (g2) driving waveform of the second low-bridge switch 303, and W12 is the second half-bridge mid-point (g3) voltage waveform.

At time t11, when the second upper bridge switch tube 302 is turned on when the duty ratio of the PWM signal is large, the second half-bridge mid-point voltage detection module 307 collects the mid-point voltage signal and sends it to the power control device 100. The power control device 100 It is detected that the voltage of the mid-point voltage (g3) of the second half-bridge is a high level of 310V, which is equal to the power supply voltage (VC2), then the voltage difference between the collector and the emitter of the second upper bridge switch tube 302 is equal to 0V, and the power control device 100 It is determined that the second upper bridge switch tube 302 is in a soft-on state. At time t12, when the second lower bridge switch tube 303 is turned on when the duty ratio of the PWM signal is large, the power control device 100 detects that the voltage at the midpoint voltage (g3) of the second half bridge is a low level of 0V, which is equal to the ground wire voltage, the voltage difference between the collector and the emitter of the second lower bridge switch 303 is equal to 0V, and the power control device 100 determines that the second lower switch 303 is in a soft-on state. Under the above conditions, the loss of the switch tube is small, and the system works stably.

However, when the PWM duty cycle of the second heating module 300 is less than a certain value, the upper-bridge switch of the half-bridge will enter a hard-on state from a soft-on state. Continuing to refer to FIG. 14 , at time t21, when the second upper bridge switch 302 with a small duty cycle of the PWM signal is turned on, the power control device 100 detects that the voltage at the midpoint voltage (g3) of the second half-bridge is low. If the power supply voltage VC2 is 310V, the voltage difference between the collector and the emitter of the second high-bridge switch 302 is equal to 310V, and the power control device 100 determines that the second high-bridge switch 302 is in a hard-on state. In this case, the loss of the second high-bridge switch tube 302 is large, and the temperature rises, which may cause damage to the second high-bridge switch tube 302 .

According to some embodiments of the present application, in step S124, before determining whether the upper bridge switch tube of the slave heating module works in a hard-on state, the following step may be further included: determining to use a continuous heating control method to control the slave heating module. Among them, the continuous heating control mode refers to the time period between each zero-crossing point in the input AC power supply, and the PWM output is turned on to work from the heating module. When the upper bridge switch tube of the slave heating module works in a soft-on state, the continuous heating control method is used to control the output power.

As shown in FIG. 12 , step S125 : if the upper bridge switch tube of the slave heating module works in a hard-on state, the upper bridge switch tube is controlled by the lost wave heating control method.

The lost wave heating control mode means that the control is turned off to input a PWM signal to the slave heating module, and the heating module 50 stops heating for a period of time to reduce the output power of the slave heating module. During the period of closing the input PWM signal to the heating module, the switch tube does not work and no switching loss occurs, thereby reducing the temperature rise of the switch tube and improving the life and reliability of the product.

For example, in some embodiments, the lost-wave heating control method is used in step S125 to control the upper bridge switch tube, which may include steps S1251-S1254:

Step S1251: Count the zero-crossing points of the input AC power supply of the electromagnetic heating device;

Step S1252: determine whether the zero-crossing count value is greater than the preset wave loss threshold;

Step S1253: when the zero-crossing point count value is greater than the preset wave loss threshold, output a PWM signal to the upper bridge switch tube, so that the slave heating module performs heating work;

Step S1254 : when the zero-crossing count value is less than or equal to the preset wave loss threshold, turn off the output PWM signal to the upper bridge switch tube, so as to stop the heating operation of the slave heating module.

Wherein, the zero-crossing detection module 101 can generate a zero-crossing signal when the AC power source is at the zero-crossing point and input it to the power control device 100 for control, and the power control device 100 can count the zero-crossing points after detecting the zero-crossing signal. A zero-crossing counter may be included, and the zero-crossing counter counts the zero-crossing points according to the zero-crossing signal, so that the power control device 100 can control whether the slave heating module outputs a PWM signal for heating before the next zero-crossing signal arrives. The preset lost wave threshold is the number of lost waves, which can be set according to the output power. The larger the number of lost waves, the smaller the output power, and the smaller the number of lost waves, the greater the output power. Therefore, by adjusting the preset wave loss threshold, the control of different output powers can be realized.

Figure 15 shows the corresponding working waveforms of the continuous heating control mode and the lost wave heating control mode. Among them, the waveform of W20 is the voltage waveform of the half-bridge power supply (VC1, VC2), and Z10, Z11, Z12, etc. are the zero-crossing marks of the input AC power supply of the electromagnetic heating device. The Z10-Z16 time period of the W21 waveform corresponds to the continuous heating control mode; in the Z16-Z17, Z18-Z19, Z110-Z111, Z112-Z113 time periods, the output PWM signal is turned off to the upper bridge switch tube, and the heating module does not work, so that the Z16 -Z1114 time period corresponds to lost wave heating control method.

Take the W21 waveform as an example, the number of lost waves is 1, and the preset lost wave threshold is 1. Before t31, use the continuous heating control mode to control the work of the slave heating module. At time t31, the power control device 100 detects that the upper bridge switch is in a hard-on state, switches to the lost-wave heating control mode, and clears the zero-crossing counter to make the zero-crossing count value (CNT) zero. At the zero-crossing time of Z16, the power control device 100 executes the method shown in FIG. 16 . After the zero-crossing counter is incremented by 1, the value of CNT is 1. Since the value of CNT is not greater than the preset drop-wave threshold, the output PWM is turned off. The signal is sent to the upper bridge switch tube, so the heating module does not work during the Z16-Z17 time period. At the time Z17 of moving down the zero-crossing point, the power control device 100 executes the method shown in FIG. 16 . After the zero-crossing counter is incremented by 1, the value of CNT is 2. Since the value of CNT is greater than the preset wave loss threshold, the zero-crossing counter Clear to zero (CNT=0), and output PWM signal to the upper bridge switch tube, so in the Z17-Z18 time period, the heating from the heating module works.

The W22 waveform is an embodiment in which the number of lost waves is 2 and the preset lost wave threshold is 2. The working process of the W21 waveform can be understood according to the working process of the W21 waveform, and will not be repeated here.

According to the power control method of the electromagnetic heating device of the embodiment of the present application, when the upper bridge switch tube of the heating module works in the hard-on state, the upper bridge switch tube is controlled by the lost wave heating control method, and the upper bridge switch tube is in a section of It does not work within a period of time and does not produce switching losses, thereby reducing the temperature rise of the upper bridge switch tube and improving the service life and reliability of the electromagnetic heating equipment.

As shown in FIG. 17 , the power control method of the electromagnetic heating device according to some embodiments of the present application may include steps S173 , S174 and S175 . details as follows:

Step S173 : when the output power of the slave heating module of the electromagnetic heating device is controlled by the power adjustment method of adjusting the duty ratio, determine the current duty cycle adjustment method for driving the slave heating module to perform the heating operation.

Step S174: When it is determined that the current duty cycle adjustment mode for driving the slave heating module to perform the heating operation is the complementary duty cycle continuous adjustment mode, determine whether the upper bridge switch tube of the slave heating module works in a hard-on state.

For example, in some embodiments, step S174: judging whether the upper bridge switch of the slave heating module works in a hard-on state, may include steps S1741 and S1742, as follows:

Step S1741: Determine whether the duty cycle of the PWM signal of the upper bridge switch is less than a preset value.

Step S1742 : if the duty cycle of the PWM signal of the upper-bridge switch is smaller than the preset value, it is determined that the upper-bridge switch is in a hard-on state.

For another example, in some embodiments, step S174: judging whether the upper bridge switch tube of the slave heating module is in a hard-on state may include steps S1743, S1744 and S1745, as follows:

Step S1743: Detect the midpoint voltage between the upper bridge switch tube and the lower bridge switch tube of the heating module;

Step S1744: Determine whether the voltage difference between the collector and the emitter of the upper bridge switch is greater than a preset voltage threshold according to the midpoint voltage;

Step S1745: When the voltage difference between the collector and the emitter of the upper-bridge switch is greater than the preset voltage threshold, it is determined that the upper-bridge switch is in a hard-on state.

resonant capacitors

resonant capacitor pair

FIG. 18 is a working waveform diagram of the second heating module 300 . W10 is the gate (g1) driving waveform of the second high-bridge switch 302, W11 is the gate (g2) driving waveform of the second low-bridge switch 303, and W12 is the second half-bridge mid-point (g3) voltage waveform.

At time t11, when the second upper bridge switch tube 302 is turned on when the duty ratio of the PWM signal is large, the second half-bridge mid-point voltage detection module 307 collects the mid-point voltage signal and sends it to the power control device 100. The power control device 100 It is detected that the voltage of the mid-point voltage (g3) of the second half-bridge is a high level of 310V, which is equal to the power supply voltage (VC2), then the voltage difference between the collector and the emitter of the second upper bridge switch tube 302 is equal to 0V, and the power control device 100 It is determined that the second upper bridge switch tube 302 is in a soft-on state. At time t12, when the second lower bridge switch tube 303 is turned on when the duty ratio of the PWM signal is large, the power control device 100 detects that the voltage at the midpoint voltage (g3) of the second half bridge is a low level of 0V, which is equal to the ground wire voltage, the voltage difference between the collector and the emitter of the second lower bridge switch 303 is equal to 0V, and the power control device 100 determines that the second lower switch 303 is in a soft-on state. Under the above conditions, the loss of the upper bridge switch tube and the lower bridge switch tube is small, and the system works stably.

However, when the PWM duty cycle of the second heating module 300 is less than a certain value, the upper-bridge switch of the half-bridge will enter a hard-on state from a soft-on state. Continuing to refer to FIG. 18 , at time t13, when the second upper bridge switch tube 302 with a small duty cycle of the PWM signal is turned on, the power control device 100 detects that the voltage at the midpoint voltage (g3) of the second half-bridge is low. If the power supply voltage VC2 is 310V, the voltage difference between the collector and the emitter of the second high-bridge switch 302 is equal to 310V, and the power control device 100 determines that the second high-bridge switch 302 is in a hard-on state. In this case, the loss of the second high-bridge switch tube 302 is large, and the temperature rises, which may seriously damage the second high-bridge switch tube 302 .

Since there are two switches in the half-bridge circuit, the upper bridge switch and the lower bridge switch, the two switches may have the following four working states:

The first is that the upper bridge switch is turned on, and the lower bridge switch is turned off, as shown in the T1 time period in Figure 18;

The second is that the upper bridge switch is turned off and the lower bridge switch is turned on, as shown in the T2 time period in Figure 18;

The third type, the upper bridge switch tube and the lower bridge switch tube are turned off at the same time, as shown in the d1 and d2 time periods in Figure 18;

Fourth, the upper bridge switch tube and the lower bridge switch tube are turned on at the same time. This situation will cause a short circuit of the power supply, resulting in permanent damage to the switch tube. Therefore, it is necessary to prevent the switch tube from working in this state.

Since the gate PWM drive signal of the switch is switched from high level to low level, the current flowing through the collector and emitter of the switch is not immediately turned off, that is, the process of turning the switch from on to off is not instantaneous. It takes a certain time (about 0.5us) to turn off completely. Therefore, in the half-bridge circuit, when any switch is turned off and the other switch is turned on, it is necessary to give the driving signal a time period (about 2us) during which the two switches are turned off at the same time, as shown in d1 and d1 in Figure 18. As shown in the d2 time period, the two switch tubes are made to work in the above third working state, to prevent the upper bridge switch tube and the lower bridge switch tube from being short-circuited, and improve the service life and safety. This time period is called dead time ( dead time).

The duty cycle refers to the ratio of the high level time length to the entire cycle length in one cycle of the PWM signal. As shown in Figure 18, T1 is the high level time length, and T3 is the length of a PWM cycle, so the duty cycle is equal to T1/T3.

For a half-bridge circuit with two switches, the PWM signal of the upper-bridge switch and the PWM signal of the lower-bridge switch can have the following two modes:

One is the complementary duty cycle mode, which means that in one PWM cycle, except for the dead time, the level of the PWM signal of the upper bridge switch and the level of the PWM signal of the lower bridge switch in other time periods are opposite to each other. There is no situation in which the upper bridge switch tube and the lower bridge switch tube are turned on at the same time. For example, as shown in Figure 20, T13 is a PWM cycle, except for the dead time d1 and d2, in other time periods, in the T11 time period, the upper bridge switch is at a high level, and the lower bridge switch is at a low level; at T12 During the time period, the upper bridge switch is at a low level, and the lower bridge switch is at a high level.

The other is the symmetrical duty cycle mode, which means that in a PWM cycle, the on-time of the upper-bridge switch is equal to the on-time of the lower-bridge switch, and the level of the PWM signal of the upper-bridge switch is the same as that of the lower-bridge switch. The levels of the PWM signals of the bridge switches are in an inverse relationship to each other. As shown in Figure 20, T23 is a PWM cycle, the conduction time T21 of the upper bridge switch is equal to the conduction time T22 of the lower bridge switch, so there may be a time period, the upper bridge switch and the lower bridge switch. The PWM of the tube is in a low level state. During the Ta time period in Figure 20, the upper bridge switch tube and the lower bridge switch tube are in the off state.

The zero-crossing time refers to the time when the AC power voltage crosses zero. As shown in Figure 19, the waveform of W20 is the voltage waveform of the half-bridge power supply (VC1 and VC2 as shown in Figure 13), in which Z10, Z11, Z12, etc. are all zero-crossing Moment sign.

According to some embodiments of the present application, in step S174, it is determined that the current duty cycle adjustment mode for driving the slave heating module to perform the heating operation is the complementary duty cycle continuous adjustment mode. Among them, the complementary duty cycle continuous adjustment method means that in two consecutive adjacent PWM signal periods, the upper bridge switch and the lower bridge switch are heated with the same duty cycle, and in one PWM cycle, two zero-crossings In the time period between the instants, the upper bridge switch tube and the lower bridge switch tube work in the above-mentioned complementary duty cycle mode, and the levels are in an inverse relationship with each other. As shown in Figure 19, in the TM1 time period of the W21 waveform, both the upper-bridge switch and the lower-bridge switch work in the complementary duty cycle mode, and in the time period M1 between two adjacent zero-crossing moments, the expanded waveform As shown in the M1 time period in Figure 20. When the upper bridge switch tube of the slave heating module works in the soft-on state, the output power is controlled by the continuous adjustment method of the complementary duty ratio.

As shown in FIG. 17, step S175: if the upper-bridge switch tube of the slave heating module works in a hard-on state, the upper-bridge switch tube and the lower-bridge switch tube are controlled by the alternate heating control method of complementary duty cycle and symmetrical duty cycle. Take control.

Complementary duty cycle - The heating control method of symmetrical duty cycle alternate means that the time period between two zero-crossing moments is the unit time, that is, one PWM signal cycle is the unit time, and the above-mentioned complementary duty cycle is output alternately. mode and symmetric duty cycle mode. In the TM2 time period as shown in Figure 19, the PWM signal in the complementary duty cycle mode is output in the M1 time period, and the PWM signal in the symmetrical duty cycle mode is output in the M2 time period. Among them, the M1 time period expansion waveform is shown in the M1 time period in Figure 20, and the M2 time period expansion waveform is shown in the M2 time period in Figure 20. The conduction time T21 of the upper bridge switch tube and the conduction time of the lower bridge switch tube The pass time T22 is equal.

The heating is controlled by the alternate heating control method of complementary duty cycle and symmetrical duty cycle, so as to avoid the high-bridge switch tube being in a hard-on state for a long time. After the switch tube and the lower bridge switch tube are controlled, the original state of the single upper bridge switch tube being hard turned on is improved to the state where the upper bridge switch tube and the lower bridge switch tube are alternately hard turned on, and the heat generated by the hard turn on is generated by the upper bridge switch tube. The independent responsibility improvement is shared by the upper bridge switch tube and the lower bridge switch tube, and the temperature rise of the switch tube is reduced by half, thereby improving the life and reliability of the product.

For example, in some embodiments, in step S175, the heating control method of alternating complementary duty cycle and symmetrical duty cycle is used to control the upper bridge switch tube and the lower bridge switch tube, which may include steps S1751-S1754:

Step S1751: Count the zero-crossing points of the input AC power supply of the electromagnetic heating device;

Step S1752: determine whether the zero-crossing count value is an odd value;

Step S1753: when the zero-crossing count value is an odd value, output a PWM signal with a symmetrical duty cycle to the upper bridge switch tube and the lower bridge switch tube, so that the slave heating module performs heating work;

Step S1754: When the zero-crossing count value is an even value, output a PWM signal with a complementary duty cycle to the upper-bridge switch tube and the lower-bridge switch tube, so that the slave heating module performs heating work.

The zero-crossing point of the input AC power supply refers to the moment when the voltage of the AC power supply crosses zero. The zero-crossing detection module 101 can generate a zero-crossing signal when the AC power source is at the zero-crossing point and input it to the power control device 100 for control. After the power control device 100 detects the zero-crossing signal, it can count the zero-crossing points. A zero-crossing counter, the zero-crossing counter counts the zero-crossing points according to the zero-crossing signal, so that the power control device 100 can control whether to output a PWM signal with a symmetrical duty cycle or a PWM signal with a complementary duty cycle to the upper bridge switch when the next zero-crossing signal arrives tube and lower bridge switch tube.

Figure 19 shows the corresponding working waveforms of the complementary duty cycle continuous adjustment mode and the complementary duty cycle-symmetrical duty cycle alternate heating control mode. Figure 20 shows the working waveforms of outputting a PWM signal with a complementary duty cycle and a PWM signal with a symmetrical duty cycle.

Among them, the waveform of W20 in Figure 19 is the voltage waveform of the half-bridge power supply (VC1, VC2), and Z10, Z11, Z12, etc. are the zero-crossing marks of the input AC power supply of the electromagnetic heating device. During the D10-D14 time period of the W21 waveform, the duty cycle of the upper bridge switch tube and the lower bridge switch tube does not change. The M1 stage working waveform shown in Figure 20 corresponds to the complementary duty cycle continuous adjustment method. The switching process of M1 and M2 in the time period D15-D112 shown in Fig. 19, and the operating waveforms of the switching tubes in the time period M1 and M2 in Fig. 20, correspond to the heating control mode of alternating complementary duty cycle and symmetrical duty cycle.

As shown in FIG. 19 , assuming that the current duty cycle of the PWM signal is 20%, before time t11, the power control device 100 adopts the complementary duty cycle continuous adjustment method, and the upper bridge switch tube operates at a 20% duty cycle, as shown in the figure As shown in the M1 time period of W30 in 20; then the lower bridge switch tube works with an 80% duty cycle, as shown in the M1 time period of W31 in Figure 20.

At time t11, the power control device 100 detects that the upper-bridge switch tube is in a hard-on state, switches to a complementary duty cycle-symmetrical duty cycle alternate heating control mode, and clears the zero-crossing counter to make the zero-crossing count value (CNT) is zero. At the zero-crossing time of Z15, the power control device 100 executes the method shown in FIG. 21. After the zero-crossing counter performs the increment operation, the value of CNT is 1, which is an odd value, and the power control device 100 outputs a PWM signal with a symmetrical duty cycle. For example, the upper bridge switch works with a 30% duty cycle, as shown in the M2 period of W30 in Figure 20; the lower bridge switch works with a 30% duty cycle, as shown in the M2 period of W31 in Figure 20. Referring to Figure 19, it can be seen that when the upper bridge switch is turned on at this stage (time t21), the voltage difference between the collector and the emitter of the upper bridge switch is zero volts, and it works in a soft-on state. When the lower switch is turned on (t22) time), the voltage difference between the collector and the emitter of the lower bridge switch is 310V, and it works in a hard-on state. The upper bridge switch tube has small loss and low temperature rise, while the lower bridge switch tube has large loss and temperature rise.

At the next zero-crossing time Z16, the power control device 100 executes the method shown in FIG. 21. After the zero-crossing counter performs the increment operation, the value of CNT is 2, which is an even value, and the power control device 100 outputs a PWM with a complementary duty cycle. signal, that is, the upper bridge switch works with 20% duty cycle, as shown in the M1 period of W30 in Figure 20; the lower bridge switch works with 80% duty cycle, as shown in the M1 period of W31 in Figure 20 . Combining with Figure 19, it can be seen that when the upper bridge switch is turned on at this stage (time t11), the voltage difference between the collector and the emitter of the upper bridge switch is 310V, and it works in a hard-on state. When the lower bridge switch is turned on (time t12) ), the voltage difference between the collector and the emitter of the lower bridge switch is zero volts, and it works in a soft-on state. The upper bridge switch tube has a large loss and a temperature rise, while the lower bridge switch tube has a small loss and a low temperature rise.

Therefore, after adopting the alternate heating control method of complementary duty cycle and symmetrical duty cycle, in the complementary duty cycle mode, the upper bridge switch tube works in a hard-on state, and in the symmetrical duty cycle mode, the lower bridge switch tube works at Hard-on state. By alternately performing complementary duty cycle and symmetrical duty cycle, the upper bridge switch tube and the lower bridge switch tube work alternately in the hard-on state, sharing the heat generated by the hard turn-on, and the temperature rise of the upper bridge switch tube is reduced by half, avoiding the upper-bridge switch tube. The bridge switch tube is in a hard-on state for a long time, resulting in an excessively high temperature rise, which is beneficial to improve the life and reliability of the electromagnetic heating equipment.

According to the power control method of the electromagnetic heating device according to some embodiments of the present application, when the upper-bridge switch tube of the heating module works in a hard-on state, the upper-bridge switch is controlled by using a complementary duty cycle-symmetric duty cycle alternate heating control method. The upper bridge switch tube and the lower bridge switch tube are controlled, so that the upper bridge switch tube and the lower bridge switch tube work alternately in the hard-on state, and share the heat generated by the hard turn-on, the temperature rise of the upper bridge switch tube is reduced, and the upper bridge switch tube is avoided for a long time. It is damaged when working in a hard-on state, which improves the life and reliability of the electromagnetic heating equipment.

As shown in FIG. 22 , the power control method of the electromagnetic heating device according to some embodiments of the present application may include steps S223 , S224 and S225 . details as follows:

Step S223 : when the plurality of heating modules 50 of the electromagnetic heating device are working at the same time, determine the slave heating module among the plurality of heating modules 50 .

The slave heating module may be a heating module 50 with a non-maximal input power among the plurality of heating modules 50 , in other words, the slave heating module may be a heating module 50 with a relatively small input power among the plurality of heating modules 50 . For example, for the method of determining the slave heating module among the plurality of heating modules 50, reference may be made to the power control method of the electromagnetic heating device described above, and its specific content and beneficial effects will not be repeated here.

Step S224 : control the output power of the slave heating module by adopting a power adjustment method of adjusting the duty ratio, and determine whether the upper bridge switch tube of the slave heating module is in a hard-on state.

For example, in some embodiments, step S224: determining whether the upper bridge switch of the slave heating module is in a hard-on state may include steps S2241 and S2242, as follows:

Step S2241: Determine whether the duty cycle of the PWM signal of the upper bridge switch is smaller than a preset value.

Step S2242: If the duty cycle of the PWM signal of the upper bridge switch tube is smaller than the preset value, it is determined that the upper bridge switch tube is in a hard-on state.

For another example, in some embodiments, step S224: determining whether the upper bridge switch tube of the slave heating module works in a hard-on state, which may include steps S2243, S2244 and S2245, as follows:

Step S2243: Detect the midpoint voltage between the upper bridge switch tube and the lower bridge switch tube of the heating module;

Step S2244: Determine whether the voltage difference between the collector and the emitter of the upper bridge switch is greater than a preset voltage threshold according to the midpoint voltage;

Step S2245: When the voltage difference between the collector and the emitter of the upper-bridge switch is greater than the preset voltage threshold, it is determined that the upper-bridge switch is in a hard-on state.

resonant capacitors

resonant capacitor pair

FIG. 23 is a working waveform diagram of the second heating module 300 . W10 is the gate (g1) driving waveform of the second high-bridge switch 302, W11 is the gate (g2) driving waveform of the second low-bridge switch 303, and W12 is the second half-bridge mid-point (g3) voltage waveform.

However, when the PWM duty cycle of the second heating module 300 is less than a certain value, the upper-bridge switch of the half-bridge will enter a hard-on state from a soft-on state. Continuing to refer to FIG. 23 , at time t13, when the second upper bridge switch 302 with a small duty cycle of the PWM signal is turned on, the power control device 100 detects that the voltage at the mid-point voltage (g3) of the second half-bridge is low. If the power supply voltage VC2 is 310V, the voltage difference between the collector and the emitter of the second high-bridge switch 302 is equal to 310V, and the power control device 100 determines that the second high-bridge switch 302 is in a hard-on state. In this case, the loss of the second high-bridge switch tube 302 is large, and the temperature rises, which may seriously damage the second high-bridge switch tube 302 .

According to some embodiments of the present application, in step S224, before determining whether the upper bridge switch tube of the slave heating module works in a hard-on state, the following step may be further included: determining to use a continuous duty cycle control method to control the slave heating module. Among them, the continuous duty cycle control mode means that in two consecutive adjacent PWM signal periods, the upper bridge switch tube and the lower bridge switch tube are heated with the same duty cycle. When the upper bridge switch tube of the slave heating module works in a soft-on state, the output power is controlled by a continuous duty cycle control method.

As shown in FIG. 22 , step S225 : if the upper bridge switch tube of the slave heating module works in a hard-on state, the upper bridge switch tube and the lower bridge switch tube are controlled by an alternate duty cycle heating control method.

The alternate duty cycle heating control mode means that with one PWM signal cycle as the unit time, the PWM duty cycle of the current unit time of the upper bridge switch and the PWM duty cycle of the next unit time are complementary. The PWM duty cycle of the current unit time and the PWM duty cycle of the next unit time are also complementary. For example, if the PWM duty cycle of the upper bridge switch is 20% and the PWM duty cycle of the lower bridge switch is 80% in the current unit time, the PWM duty cycle of the upper bridge switch in the next unit time is 80%, and the PWM duty cycle of the lower bridge switch is 80%. The PWM duty cycle is 20%.

The heating is controlled by the alternate duty cycle to avoid the upper bridge switch being in a hard-on state for a long time. In other words, after the upper and lower bridge switches are controlled by the alternate duty cycle heating control method, a single upper The state of hard turn-on of the tubes is improved to the state where the upper bridge switch tube and the lower bridge switch tube are turned on alternately, and the heat generated by the hard turn on is independently borne by the upper bridge switch tube and improved to be shared by the upper bridge switch tube and the lower bridge switch tube. Tube temperature rise is reduced by half, thereby increasing product life and reliability.

For example, in some embodiments, in step S225, an alternate duty cycle heating control method is used to control the upper bridge switch tube and the lower bridge switch tube, which may include steps S2251-S2254:

Step S2251: Count the zero-crossing points of the input AC power supply of the electromagnetic heating device;

Step S2252: determine whether the zero-crossing count value is an odd value;

Step S2253: when the zero-cross count value is an odd value, output the PWM signal of the forward duty cycle to the upper bridge switch tube and the lower bridge switch tube, so that the slave heating module performs heating work;

Step S2254: When the zero-crossing count value is an even value, output a PWM signal with a reverse duty cycle to the upper bridge switch tube and the lower bridge switch tube, so that the slave heating module performs heating work.

The zero-crossing point of the input AC power supply refers to the moment when the voltage of the AC power supply crosses zero. The zero-crossing detection module 101 can generate a zero-crossing signal when the AC power source is at the zero-crossing point and input it to the power control device 100 for control. After the power control device 100 detects the zero-crossing signal, it can count the zero-crossing points. A zero-crossing counter, the zero-crossing counter counts the zero-crossing points according to the zero-crossing signal, so that the power control device 100 can control whether to output the PWM signal of the forward duty cycle or the PWM signal of the reverse duty cycle when the next zero-crossing signal arrives Bridge switch tube and lower bridge switch tube.

Figure 24 shows the corresponding working waveforms of the continuous duty cycle heating control mode and the alternate duty cycle heating control mode. Figure 25 shows the working waveforms of outputting a PWM signal with a forward duty cycle and a PWM signal with a reverse duty cycle.

Among them, the waveform of W20 in Figure 24 is the voltage waveform of the half-bridge power supply (VC1, VC2), and Z10, Z11, Z12, etc. are the zero-crossing marks of the input AC power supply of the electromagnetic heating device. During the D10-D14 time period of the W21 waveform, the duty cycle of the upper bridge switch tube and the lower bridge switch tube does not change. The M1 stage working waveform shown in Figure 25 corresponds to the continuous duty cycle heating control mode. The switching process of M1 and M2 in the time period D15-D112 shown in FIG. 24 , and the operating waveforms of the switching tubes in the time period M1 and M2 in FIG. 25 correspond to the alternate duty cycle heating control method.

As shown in FIG. 24 , assuming that the current duty cycle of the PWM signal is 20%, before time t31, the power control device 100 adopts the continuous duty cycle heating control mode, and the upper bridge switch tube operates at a 20% duty cycle, as shown in the figure As shown in the M1 time period of W30 in Figure 25; then the lower bridge switch tube works with an 80% duty cycle, as shown in the M1 time period of W31 in Figure 25.

At time t31, the power control device 100 detects that the upper bridge switch is in a hard-on state, switches to the alternate duty cycle heating control mode, and clears the zero-crossing counter to make the zero-crossing count value (CNT) zero. At the zero-crossing time of Z15, the power control device 100 executes the method shown in FIG. 26. After the zero-crossing counter performs the increment operation, the value of CNT is 1, which is an odd value, and the power control device 100 outputs a PWM with a reverse duty cycle. signal, that is, the upper bridge switch works at 80% duty cycle, as shown in the M2 time period of W30 in Figure 25; then the lower bridge switch works at 20% duty cycle, as shown in the M2 time period of W31 in Figure 25 Show. Combining with Figure 24, it can be seen that when the upper bridge switch is turned on at this stage, the voltage difference between the collector and the emitter of the upper bridge switch is zero volts, and it works in a soft-on state. The voltage difference between the electrode and the emitter is 310V, and it works in a hard-on state. The upper bridge switch tube has small loss and low temperature rise, while the lower bridge switch tube has large loss and temperature rise.

At the next zero-crossing time Z16, the power control device 100 executes the method shown in FIG. 26. After the zero-crossing counter performs the increment operation, the value of CNT is 2, which is an even value.

The power control device 100 outputs a PWM signal with a forward duty cycle, that is, the upper bridge switch operates at a 20% duty cycle, as shown in the M1 time period of W30 in Figure 25; then the lower bridge switch operates at an 80% duty cycle work, as shown in the M1 period of W31 in Figure 25. Referring to Fig. 24, it can be seen that at this stage, when the upper bridge switch is turned on, it works in a hard-on state, and when the lower bridge switch is turned on, it works in a soft-on state. The upper bridge switch tube has a large loss and a temperature rise, while the lower bridge switch tube has a small loss and a low temperature rise.

Therefore, after adopting the alternate duty cycle heating control method, the upper bridge switch tube and the lower bridge switch tube work alternately in the hard-on state, sharing the heat generated by the hard turn-on, and the temperature rise of the upper bridge switch tube is reduced by half, avoiding the upper-bridge switch tube. The bridge switch tube is in a hard-on state for a long time, resulting in an excessively high temperature rise, which is beneficial to improve the life and reliability of the electromagnetic heating equipment.

The duty cycle refers to the ratio of the high level time length to the entire cycle length in one cycle of the PWM signal. As shown in Figure 23, T1 is the high level time length, and T2 is the length of a PWM cycle, so the duty cycle is equal to T1/T2. For a half-bridge circuit with two switches, the PWM switch of the upper-bridge switch and the PWM switch of the lower-bridge switch are complementary on and off. In other words, when the upper-bridge switch is turned on, the lower-bridge switch is turned off. When the upper bridge switch tube is turned off, the lower bridge switch tube is turned on, and there is no situation that the upper bridge switch tube and the lower bridge switch tube are turned on at the same time.

Therefore, for the power control device 100 to output a PWM value with a duty cycle, the duty cycle value of the upper bridge switch and the duty cycle value of the lower bridge switch are complementary. For example, if the power control device 100 outputs a 20% duty cycle PWM value, the upper bridge switch tube PWM duty cycle value is 20%, and the lower bridge switch tube PWM duty cycle value is 80%. For a half-bridge switching heating system, the output power of 20% PWM duty cycle is equal to the output power of 80% PWM duty cycle. Therefore, when the duty cycle of the PWM signal output to the upper bridge switch is in the range of 0-50%, it is called forward duty cycle, and when the duty cycle of the PWM signal output to the upper bridge switch is in the range of 51-100%, called the reverse duty cycle.

In addition, in the half-bridge circuit, when any switch is turned off and the other switch is turned on, there will be a time period (about 2us) during which both switches are turned off. This time period is called dead time ( dead time), as shown in the d1 and d2 time periods in Figure 23, this is because when the gate PWM drive signal of the switch is switched from high level to low level, the current flowing through the collector and emitter of the switch is not immediately It takes a certain time (about 0.5us) to turn off completely. Therefore, the dead time is used to prevent the short-circuit of the upper bridge switch tube and the lower bridge switch tube from being short-circuited, so as to improve the service life and safety.

According to the power control method of the electromagnetic heating device according to some embodiments of the present application, when the upper bridge switch tube of the heating module works in a hard-on state, the upper bridge switch tube and the lower bridge switch tube are controlled by using an alternate duty cycle heating control method. Control, make the upper bridge switch tube and the lower bridge switch tube work alternately in the hard-on state, share the heat generated by the hard turn-on, reduce the temperature rise of the upper bridge switch tube, and prevent the upper bridge switch tube from being damaged by working in the hard-on state for a long time. , improve the life and reliability of electromagnetic heating equipment.

According to the power control device 100 of an electromagnetic heating device according to some embodiments of the present application, when the upper bridge switch tube of the slave heating module works in a hard-on state, the upper bridge switch tube is controlled by the lost wave heating control method, and the upper bridge switch tube is controlled by the lost wave heating control method. It does not work for a period of time and does not produce switching loss, thereby reducing the temperature rise of the upper bridge switch tube and improving the service life and reliability of the electromagnetic heating equipment.

In some embodiments of the present application, the first determination module 30 determines a method for the slave heating module, a method for the power control module 20 to control the output power of the slave heating module by using a power adjustment method of adjusting the duty cycle, and the second determination module 40. The method for determining whether the upper bridge switch of the slave heating module works in the hard-on state, and the method for the power control module 20 to control the upper bridge switch tube by using the lost wave heating control mode can refer to the power control method of the electromagnetic heating device described above. , and will not be repeated here.

The computer-readable storage medium according to the embodiment of the present application stores thereon a power control program of the electromagnetic heating device, and when the power control program of the electromagnetic heating device is executed by the processor, realizes the power control of the electromagnetic heating device according to the embodiment of the present application method, or realize the power control method of the electromagnetic heating device as the embodiment of the present application.

Since the power control method for an electromagnetic heating device according to the embodiment of the present application has the above-mentioned beneficial technical effects, the power control program stored in the computer-readable storage medium according to the embodiment of the present application realizes the description of the above-mentioned embodiment when the power control program stored therein is executed by the processor. According to the power control method, the output power is controlled by different power adjustment methods for different types of heating modules 50, which is conducive to realizing the frequency consistency of multiple heating modules 50 working at the same time, thereby avoiding the mixing of multiple frequencies during the working process. The synthetic frequency is generated together to avoid the sharp and harsh noise caused by the synthetic difference frequency signal, which is beneficial to improve the user experience.

Since the power control method for an electromagnetic heating device according to the embodiment of the present application has the above-mentioned beneficial technical effects, the power control program stored in the computer-readable storage medium according to the embodiment of the present application realizes the description of the above-mentioned embodiment when the power control program stored therein is executed by the processor. The power control method is based on the above-mentioned power control method, by adopting the lost wave heating control method to control the upper bridge switch tube when the upper bridge switch tube of the heating module works in the hard-on state, the upper bridge switch tube does not work for a period of time, and no switching loss occurs. , thereby reducing the temperature rise of the upper bridge switch tube and improving the service life and reliability of the electromagnetic heating equipment.

The electromagnetic heating device according to the embodiment of the present application includes a memory, a processor, and a power control program of the electromagnetic heating device that is stored in the memory and can be run on the processor. A power control method for an electromagnetic heating device, or a power control method for an electromagnetic heating device as an embodiment of the present application is implemented.

Since the power control method for the electromagnetic heating device according to the embodiment of the present application has the above-mentioned beneficial technical effects, the electromagnetic heating device according to the embodiment of the present application controls the output power by using different power adjustment methods for different types of heating modules 50, It is beneficial to realize the frequency consistency of the multiple heating modules 50 working at the same time, so as to avoid the mixing of multiple frequencies during the working process to generate a synthetic frequency, and to avoid synthesizing the difference frequency signal to generate a sharp and harsh noise, which is beneficial to improve the use of users. experience.

Since the power control method of the electromagnetic heating device according to the embodiment of the present application has the above-mentioned beneficial technical effects, the electromagnetic heating device according to the embodiment of the present application adopts the throwing method when the upper bridge switch tube of the heating module works in the hard-on state. The wave heating control method controls the upper bridge switch tube, and the upper bridge switch tube does not work for a period of time without switching loss, thereby reducing the temperature rise of the upper bridge switch tube and improving the service life and reliability of the electromagnetic heating equipment.

Other structures and operations of the electromagnetic heating device according to the embodiments of the present application are known to those of ordinary skill in the art, and will not be described in detail here.

In the description of this specification, reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., means a specific feature described in connection with the embodiment or example, A structure, material, or feature is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples, without conflicting each other.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In the description of the present application, "plurality" means at least two, such as two, three, etc., unless expressly and specifically defined otherwise.

Any process or method description in the flowcharts or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing custom logical functions or steps of the process , and the scope of the preferred embodiments of the present application includes alternative implementations in which the functions may be performed out of the order shown or discussed, including performing the functions substantially concurrently or in the reverse order depending upon the functions involved, which should It is understood by those skilled in the art to which the embodiments of the present application belong.

The logic and/or steps represented in flowcharts or otherwise described herein, for example, may be considered an ordered listing of executable instructions for implementing the logical functions, may be embodied in any computer-readable medium, For use with, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other system that can fetch instructions from and execute instructions from an instruction execution system, apparatus, or apparatus) or equipment. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport the program for use by or in connection with an instruction execution system, apparatus, or apparatus. More specific examples (non-exhaustive list) of computer readable media include the following: electrical connections with one or more wiring (electronic devices), portable computer disk cartridges (magnetic devices), random access memory (RAM), Read Only Memory (ROM), Erasable Editable Read Only Memory (EPROM or Flash Memory), Fiber Optic Devices, and Portable Compact Disc Read Only Memory (CDROM). In addition, the computer readable medium may even be paper or other suitable medium on which the program may be printed, as the paper or other medium may be optically scanned, for example, followed by editing, interpretation, or other suitable medium as necessary process to obtain the program electronically and then store it in computer memory.

It should be understood that various parts of this application may be implemented in hardware, software, firmware, or a combination thereof. In the above-described embodiments, various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented by any one of the following techniques known in the art, or a combination thereof: discrete with logic gates for implementing logic functions on data signals Logic circuits, application specific integrated circuits with suitable combinational logic gates, Programmable Gate Arrays (PGA), Field Programmable Gate Arrays (FPGA), etc.

Those skilled in the art can understand that all or part of the steps carried by the methods of the above embodiments can be completed by instructing the relevant hardware through a program, and the program can be stored in a computer-readable storage medium, and the program can be stored in a computer-readable storage medium. When executed, one or a combination of the steps of the method embodiment is included.

In addition, each functional unit in each embodiment of the present application may be integrated into one processing module, or each unit may exist physically alone, or two or more units may be integrated into one module. The above-mentioned integrated modules can be implemented in the form of hardware, and can also be implemented in the form of software function modules. If the integrated modules are implemented in the form of software functional modules and sold or used as independent products, they may also be stored in a computer-readable storage medium.

The above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, and the like. Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limitations to the present application. Embodiments are subject to variations, modifications, substitutions and variations.

In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", " Back, Left, Right, Vertical, Horizontal, Top, Bottom, Inner, Outer, Clockwise, Counterclockwise, Axial , "radial", "circumferential" and other indicated orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the application and simplifying the description, rather than indicating or implying the indicated device or Elements must have a particular orientation, be constructed and operate in a particular orientation and are therefore not to be construed as limitations on this application.

In this application, unless otherwise expressly specified and limited, the terms "installation", "connection", "connection", "fixation" and other terms should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection , or integrated; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal communication between the two elements or the interaction relationship between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific situations.

In this application, unless otherwise expressly stated and defined, a first feature "on" or "under" a second feature may be in direct contact with the first and second features, or the first and second features indirectly through an intermediary touch. Also, the first feature being "above", "over" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is level higher than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature has a lower level than the second feature.

Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limitations to the present application. Embodiments are subject to variations, modifications, substitutions and variations.

Claims

A power control method for electromagnetic heating equipment, comprising the following steps:

When it is determined that a plurality of heating modules of the electromagnetic heating device are working simultaneously, the input power of each heating module is obtained, and when the input power of the plurality of heating modules is different, the input power of each heating module is determined according to the input power of each heating module Determine the type of the corresponding heating module;

According to the type of each heating module, different power adjustment methods are used to control the output power of the corresponding heating module.
The power control method of an electromagnetic heating device according to claim 1, wherein the types of the heating modules include a master heating module and a slave heating module, wherein the type of the corresponding heating module is determined according to the input power of each heating module ,include:

The heating module with the largest input power among the plurality of heating modules is acquired, and the heating module with the largest input power is used as the master heating module, and the remaining heating modules in the plurality of heating modules are used as the slave heating modules.
The power control method for an electromagnetic heating device according to claim 2, wherein, according to the type of each heating module, different power adjustment methods are used to control the output power of the corresponding heating module, including:

When it is determined that the current heating module is the main heating module, the output power of the main heating module is controlled by adopting a frequency modulation power adjustment method;

When it is determined that the current heating module is the slave heating module, the output power of the slave heating module is controlled by adopting a power adjustment method of adjusting the duty ratio.
The power control method for an electromagnetic heating device according to claim 3, wherein the output power of the main heating module is controlled by a frequency modulation power adjustment method, comprising:

A first PWM signal with a fixed duty cycle is output to the main heating module, and the output power of the main heating module is controlled by adjusting the frequency of the first PWM signal.
The power control method of an electromagnetic heating device according to claim 4, wherein the output power of the slave heating module is controlled by a power adjustment method of adjusting the duty ratio, comprising:

A second PWM signal with a fixed frequency is output to the slave heating module, and the output power of the slave heating module is controlled by adjusting the duty ratio of the second PWM signal.
The power control method of an electromagnetic heating apparatus according to claim 5, wherein the frequency of the second PWM signal is the same as the frequency of the first PWM signal.
The power control method for an electromagnetic heating device according to claim 5 or 6, wherein the fixed duty cycle is 50%, and the duty cycle of the second PWM signal is adjustable from 0 to 50%.
The power control method for an electromagnetic heating device according to any one of claims 1 to 7, wherein when it is determined that the electromagnetic heating device has only one heating module to work, a frequency modulation power adjustment method is used to adjust the power of the heating module. The output power is controlled.
The power control method for an electromagnetic heating device according to any one of claims 1-8, wherein the method comprises the following steps:

When the output power of the slave heating module of the electromagnetic heating device is controlled by the power adjustment method of adjusting the duty ratio, determining the current duty cycle adjustment method for driving the slave heating module to perform the heating operation;

When it is determined that the current duty cycle adjustment mode for driving the slave heating module to perform the heating operation is the complementary duty cycle continuous adjustment mode, determine whether the upper bridge switch tube of the slave heating module works in a hard-on state;

If the upper-bridge switch tube of the slave heating module works in a hard-on state, the upper-bridge switch tube and the lower-bridge switch tube of the slave heating module are controlled by a complementary duty cycle-symmetric duty cycle alternate heating control method. control.
The power control method for electromagnetic heating equipment according to claim 9, wherein judging whether the upper bridge switch tube of the slave heating module works in a hard-on state, comprising:

Determine whether the duty cycle of the PWM signal of the upper bridge switch is less than a preset value;

If the duty cycle of the PWM signal of the upper-bridge switch is smaller than the preset value, it is determined that the upper-bridge switch is in a hard-on state.
The power control method for electromagnetic heating equipment according to claim 9, wherein judging whether the upper bridge switch tube of the slave heating module works in a hard-on state, comprising:

Detecting the midpoint voltage between the upper bridge switch tube and the lower bridge switch tube of the slave heating module;

Determine whether the voltage difference between the collector and the emitter of the upper bridge switch is greater than a preset voltage threshold according to the midpoint voltage;

When the voltage difference between the collector and the emitter of the upper-bridge switch is greater than a preset voltage threshold, it is determined that the upper-bridge switch is in a hard-on state.
The power control method for an electromagnetic heating device according to any one of claims 9 to 11, wherein a complementary duty cycle-symmetrical duty cycle alternate heating control method is used to control the upper-bridge switch tube and the upper bridge switch of the slave heating module. The lower bridge switch tube is controlled, including:

Counting the zero-crossing points of the input AC power of the electromagnetic heating device;

Determine whether the zero-crossing count value is an odd value;

When the zero-crossing count value is an odd value, output a PWM signal with a symmetrical duty cycle to the upper bridge switch tube and the lower bridge switch tube, so that the slave heating module performs heating work;

When the count value of the zero-crossing point is an even value, a PWM signal with a complementary duty cycle is output to the upper bridge switch tube and the lower bridge switch tube, so that the slave heating module performs heating work.
The power control method for an electromagnetic heating device as claimed in claim 12, wherein the complementary duty cycle refers to the level of the PWM signal of the upper bridge switch tube being the same as the level of the PWM signal in one PWM cycle, excluding dead time. The levels of the PWM signals of the lower bridge switches are in an inverse relationship with each other; the symmetrical duty cycle refers to the level of the PWM signals of the upper bridge switches and the lower bridge switches in one PWM cycle. The levels of the PWM signals have an inverse relationship with each other, and the conduction time of the upper bridge switch is equal to the conduction time of the lower bridge switch.
The power control method for an electromagnetic heating device according to any one of claims 1-8, wherein the method comprises the following steps:

When a plurality of heating modules of the electromagnetic heating device are working at the same time, determining a slave heating module among the plurality of heating modules;

The output power of the slave heating module is controlled by a power adjustment method of adjusting the duty ratio, and it is determined whether the upper bridge switch tube of the slave heating module works in a hard-on state;

If the upper bridge switch tube of the slave heating module works in a hard-on state, the upper bridge switch tube and the lower bridge switch tube of the slave heating module are controlled by an alternate duty cycle heating control method.
The power control method for an electromagnetic heating device according to claim 14, wherein determining whether the upper bridge switch tube of the slave heating module works in a hard-on state, comprising:

Determine whether the duty cycle of the PWM signal of the upper bridge switch is less than a preset value;

If the duty cycle of the PWM signal of the upper-bridge switch is smaller than the preset value, it is determined that the upper-bridge switch is in a hard-on state.
The power control method for an electromagnetic heating device according to claim 14, wherein determining whether the upper bridge switch tube of the slave heating module works in a hard-on state, comprising:

Detecting the midpoint voltage between the upper bridge switch tube and the lower bridge switch tube of the slave heating module;

Determine whether the voltage difference between the collector and the emitter of the upper bridge switch is greater than a preset voltage threshold according to the midpoint voltage;

When the voltage difference between the collector and the emitter of the upper-bridge switch is greater than a preset voltage threshold, it is determined that the upper-bridge switch is in a hard-on state.
The power control method for an electromagnetic heating device according to any one of claims 14-16, wherein an alternate duty cycle heating control method is used to control the upper bridge switch tube and the lower bridge switch tube of the slave heating module, include:

Counting the zero-crossing points of the input AC power of the electromagnetic heating device;

Determine whether the zero-crossing count value is an odd value;

When the zero-cross count value is an odd value, output a PWM signal with a forward duty cycle to the upper-bridge switch tube and the lower-bridge switch tube, so that the slave heating module performs heating work;

When the count value of the zero-crossing point is an even value, output a PWM signal with a reverse duty cycle to the upper bridge switch tube and the lower bridge switch tube, so that the slave heating module performs heating work.
The power control method for electromagnetic heating equipment according to claim 17, wherein when the duty cycle of the PWM signal output to the upper bridge switch is in the range of 0-50%, it is the forward duty cycle, and the output When the duty cycle of the PWM signal to the upper bridge switch is in the range of 51-100%, it is the reverse duty cycle.
The power control method for an electromagnetic heating device according to any one of claims 1-8, wherein the method comprises the following steps:

When a plurality of heating modules of the electromagnetic heating device are working at the same time, determining a slave heating module among the plurality of heating modules;

The output power of the slave heating module is controlled by a power adjustment method of adjusting the duty ratio, and it is determined whether the upper bridge switch tube of the slave heating module works in a hard-on state;

If the upper bridge switch tube of the slave heating module works in a hard-on state, the upper bridge switch tube is controlled by a lost wave heating control method.
The power control method for an electromagnetic heating device according to claim 19, wherein determining whether the upper bridge switch tube of the slave heating module works in a hard-on state, comprising:

Determine whether the duty cycle of the PWM signal of the upper bridge switch is less than a preset value;

If the duty cycle of the PWM signal of the upper-bridge switch is smaller than the preset value, it is determined that the upper-bridge switch is in a hard-on state.
The power control method for an electromagnetic heating device according to claim 19, wherein determining whether the upper bridge switch tube of the slave heating module works in a hard-on state, comprising:

Detecting the midpoint voltage between the upper bridge switch tube and the lower bridge switch tube of the slave heating module;

Determine whether the voltage difference between the collector and the emitter of the upper bridge switch is greater than a preset voltage threshold according to the midpoint voltage;

When the voltage difference between the collector and the emitter of the upper-bridge switch is greater than a preset voltage threshold, it is determined that the upper-bridge switch is in a hard-on state.
The power control method for an electromagnetic heating device according to any one of claims 19-21, wherein the upper bridge switch tube is controlled by a lost-wave heating control method, comprising:

Counting the zero-crossing points of the input AC power of the electromagnetic heating device;

Determine whether the zero-crossing count value is greater than the preset wave loss threshold;

When the zero-crossing count value is greater than the preset wave loss threshold, output a PWM signal to the upper bridge switch tube, so that the slave heating module performs heating work;

When the zero-crossing count value is less than or equal to the preset wave loss threshold, the output PWM signal to the upper bridge switch is turned off, so that the slave heating module stops the heating operation.
A computer-readable storage medium, wherein a power control program of an electromagnetic heating device is stored thereon, and when the power control program of the electromagnetic heating device is executed by a processor, the electromagnetic heating device according to any one of claims 1-22 is implemented. Power control method for heating equipment.
An electromagnetic heating device, comprising a memory, a processor, and a power control program of the electromagnetic heating device stored on the memory and running on the processor, when the processor executes the power control program, the power control program as claimed in the claims is realized. The power control method of the electromagnetic heating device according to any one of 1-22.
A power control device for electromagnetic heating equipment, comprising:

A determination module, configured to obtain the input power of each heating module when it is determined that the multiple heating modules of the electromagnetic heating device are working at the same time, and when the input power of the multiple heating modules is different, according to the input power of each heating module The input power of the heating module determines the type of the corresponding heating module;

The power control module is used to control the output power of the corresponding heating module by adopting different power adjustment methods according to the type of each heating module.