CN114698167B

CN114698167B - Electromagnetic heating equipment, power control method and power control device thereof

Info

Publication number: CN114698167B
Application number: CN202011589013.9A
Authority: CN
Inventors: 曾露添; 朱成彬; 雷俊; 江德勇; 刘文华; 王云峰
Original assignee: Foshan Shunde Midea Electrical Heating Appliances Manufacturing Co Ltd
Current assignee: Foshan Shunde Midea Electrical Heating Appliances Manufacturing Co Ltd
Priority date: 2020-12-29
Filing date: 2020-12-29
Publication date: 2023-06-27
Anticipated expiration: 2040-12-29
Also published as: CN114698167A

Abstract

The invention discloses electromagnetic heating equipment, a power control method and a power control device thereof, wherein the power control method of the electromagnetic heating equipment comprises the following steps: when the output power of the secondary heating module of the electromagnetic heating equipment is controlled by adopting a duty ratio adjusting power adjusting mode, determining a current duty ratio adjusting mode for driving the secondary heating module to perform heating work; when the current duty ratio adjusting mode for driving the secondary heating module to perform heating operation is a complementary duty ratio continuous adjusting mode, judging whether an upper bridge switching tube of the secondary heating module works in a hard on state or not; and if the upper bridge switching tube of the slave heating module works in a hard on state, controlling the upper bridge switching tube and the lower bridge switching tube of the slave heating module by adopting a heating control mode of alternating complementary duty ratio and symmetrical duty ratio. According to the power control method of the electromagnetic heating equipment, disclosed by the embodiment of the invention, the loss of the upper bridge switching tube can be prevented from being large, the temperature rise is reduced, and the service life and the reliability are improved.

Description

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

Technical Field

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

Background

In the related art, when the burner works, the switching tube may enter a hard-on state from a soft-on state, the loss of the switching tube increases, the temperature increases, the switching tube is damaged, and the reliability of a product is reduced.

Disclosure of Invention

The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the invention provides a power control method of electromagnetic heating equipment, which can prevent the loss of an upper bridge switching tube from being large, reduce the temperature rise and improve the service life and the reliability.

The invention also proposes a computer readable storage medium.

The invention also provides electromagnetic heating equipment capable of realizing the power control method.

The invention also provides a power control device of the electromagnetic heating equipment.

In order to achieve the above object, an embodiment of the present invention provides a power control method for an electromagnetic heating apparatus, including the following steps: when the output power of the secondary heating module of the electromagnetic heating equipment is controlled by adopting a duty ratio adjusting power adjusting mode, determining a current duty ratio adjusting mode for driving the secondary heating module to perform heating work; when the current duty ratio adjusting mode for driving the secondary heating module to perform heating work is a complementary duty ratio continuous adjusting mode, judging whether an upper bridge switching tube of the secondary heating module works in a hard on state or not; and if the upper bridge switching tube of the secondary heating module works in a hard on state, controlling the upper bridge switching tube and the lower bridge switching tube of the secondary heating module in a heating control mode of alternating complementary duty ratio and symmetrical duty ratio.

According to the power control method of the electromagnetic heating equipment, when the upper bridge switching tube of the secondary heating module works in the hard on state, the upper bridge switching tube and the lower bridge switching tube are controlled in a heating control mode with the complementary duty ratio-symmetrical duty ratio alternation, so that the upper bridge switching tube and the lower bridge switching tube work in the hard on state alternately, heat generated by the hard on is shared together, the temperature rise of the upper bridge switching tube is reduced, the upper bridge switching tube is prevented from being damaged due to long-time working in the hard on state, and the service life and reliability of the electromagnetic heating equipment are improved.

In addition, the power control method of the electromagnetic heating apparatus according to the above embodiment of the present invention may further have the following additional technical features:

according to some embodiments of the present invention, determining whether the upper bridge switching tube of the slave heating module is operating in a hard on state includes: judging whether the duty ratio of the PWM signal of the upper bridge switching tube is smaller than a preset value or not; and if the duty ratio of the PWM signal of the upper bridge switching tube is smaller than a preset value, determining that the upper bridge switching tube works in a hard-on state.

According to some embodiments of the present invention, determining whether the upper bridge switching tube of the slave heating module is operating in a hard on state includes: detecting the midpoint voltage between an upper bridge switching tube and a lower bridge switching tube of the secondary heating module; judging whether the voltage difference between the collector and the emitter of the upper bridge switching tube is larger than a preset voltage threshold value or not according to the midpoint voltage; and when the voltage difference between the collector and the emitter of the upper bridge switching tube is larger than a preset voltage threshold value, determining that the upper bridge switching tube works in a hard opening state.

According to some embodiments of the present invention, the control method for controlling the upper bridge switching tube and the lower bridge switching tube of the secondary heating module by adopting a heating control mode of alternating complementary duty cycle and symmetrical duty cycle includes: counting zero crossing points of an input alternating current power supply of the electromagnetic heating equipment; judging whether the zero crossing point count value is an odd value or not; when the zero crossing point count value is an odd value, PWM signals with symmetrical duty ratios are output to the upper bridge switching tube and the lower bridge switching tube so that the secondary heating module performs heating operation; and when the zero crossing point count value is an even value, outputting PWM signals with complementary duty ratios to the upper bridge switching tube and the lower bridge switching tube so as to enable the slave heating module to perform heating operation.

According to some embodiments of the invention, the complementary duty ratio refers to that the level of the PWM signal of the upper bridge switching tube and the level of the PWM signal of the lower bridge switching tube are in an inverse relationship in one PWM period except dead time; the symmetrical duty ratio refers to that in one PWM period, the level of the PWM signal of the upper bridge switching tube and the level of the PWM signal of the lower bridge switching tube are in opposite relation, and the conduction time of the upper bridge switching tube is equal to the conduction time of the lower bridge switching tube.

According to some embodiments of the invention, before the output power of the secondary heating module of the electromagnetic heating apparatus is controlled by adopting a duty cycle adjusting power adjustment mode, the method further comprises: and acquiring a heating module with the largest input power from a plurality of heating modules of the electromagnetic heating equipment, taking the heating module with the largest input power as a master heating module, and taking the rest heating modules from the plurality of heating modules as slave heating modules.

According to some embodiments of the invention, the output power of the main heating module is controlled by using a frequency-modulated power regulation mode.

According to some embodiments of the present invention, the output power of the main heating module is controlled by using a frequency-modulated power regulation method, including: and outputting a first PWM signal with a fixed duty ratio to the main heating module, and controlling the output power of the main heating module by adjusting the frequency of the first PWM signal.

According to some embodiments of the invention, the power adjustment method for adjusting the duty ratio is used to control the output power of the secondary heating module, and the method includes: and outputting a second PWM signal with fixed frequency to the secondary heating module, and controlling the output power of the secondary heating module by adjusting the duty ratio of the second PWM signal.

To achieve the above object, an embodiment of the present invention provides a computer readable storage medium having stored thereon a power control program of an electromagnetic heating apparatus, which when executed by a processor, implements a power control method of an electromagnetic heating apparatus according to an embodiment of the present invention.

In order to achieve the above objective, an embodiment of the present invention provides an electromagnetic heating device, including a memory, a processor, and a power control program of the electromagnetic heating device stored in the memory and capable of running on the processor, where the power control program is executed by the processor, to implement the power control method of the electromagnetic heating device according to the embodiment of the present invention.

To achieve the above object, an embodiment of the present invention provides a power control device of an electromagnetic heating apparatus, including: the power control module is used for determining a current duty ratio regulating mode for driving the secondary heating module to heat when the power regulating mode for regulating the duty ratio is adopted to control the output power of the secondary heating module of the electromagnetic heating equipment; the judging module is used for judging whether the upper bridge switching tube of the secondary heating module works in a hard on state or not when the current duty ratio adjusting mode for driving the secondary heating module to perform heating work is a complementary duty ratio continuous adjusting mode; the power control module is also used for controlling the upper bridge switching tube and the lower bridge switching tube of the secondary heating module by adopting a heating control mode of alternating complementary duty ratio and symmetrical duty ratio when the upper bridge switching tube of the secondary heating module works in a hard on state.

According to the power control device of the electromagnetic heating equipment, when the upper bridge switching tube of the secondary heating module works in the hard on state, the upper bridge switching tube and the lower bridge switching tube are controlled in a heating control mode of alternating complementary duty ratio-symmetrical duty ratio, so that the upper bridge switching tube and the lower bridge switching tube work in the hard on state alternately, heat generated by the hard on is shared together, the temperature rise of the upper bridge switching tube is reduced, damage caused by long-time working of the upper bridge switching tube in the hard on state is avoided, and the service life and reliability of the electromagnetic heating equipment are improved.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

The foregoing and/or additional aspects and advantages of the invention will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic diagram of a power control device according to some embodiments of the invention;

FIG. 2 is a flow chart of a method of power control of an electromagnetic heating apparatus according to some embodiments of the invention;

FIG. 3 is a flow chart of step S1 of a power control method according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a power control device and a heating module according to one embodiment of the invention;

FIG. 5 is a graph of PWM frequency versus output power for a primary heating module according to an embodiment of the invention;

FIG. 6 is a flow chart of controlling the output power of a main heating module using a frequency modulated power regulation in accordance with an embodiment of the present invention;

fig. 7 is a PWM waveform diagram of a power control device output master heating module according to an embodiment of the present invention;

FIG. 8 is a graph of duty cycle versus output power for a slave heating module with half-bridge switching tube PWM frequency for the slave heating module equal to the master heating module according to an embodiment of the present invention;

FIG. 9 is a flow chart of controlling the output power from a heating module using duty cycle power regulation in accordance with an embodiment of the present invention;

fig. 10 is a PWM waveform diagram of a power control apparatus outputting a master heating module and a slave heating module according to an embodiment of the present invention;

FIG. 11 is a schematic diagram of a power control device according to further embodiments of the present invention;

FIG. 12 is a flow chart of a method of controlling power of an electromagnetic heating apparatus according to further embodiments of the present invention;

FIG. 13 is a schematic diagram of a power control device and a heating module according to another embodiment of the invention;

FIG. 14 is an operational waveform diagram of a 50% duty cycle and 20% duty cycle switching tube according to an embodiment of the present invention;

FIG. 15 is a waveform diagram of operation corresponding to a complementary duty cycle continuous adjustment mode and a complementary duty cycle-symmetrical duty cycle alternating heating control mode in accordance with an embodiment of the present invention;

fig. 16 is an operational waveform diagram of outputting a PWM signal of complementary duty cycle and a PWM signal of symmetrical duty cycle to a switching tube according to an embodiment of the present invention;

fig. 17 is a flow chart of controlling upper and lower bridge switching tubes using a complementary duty cycle-symmetrical duty cycle alternating heating control scheme in accordance with an embodiment of the present invention.

Description of the drawings:

a power control device 100; a heating module 50;

a determination module 10; a power control module 20; a judgment module 30;

a first heating module 200; a first driving module 201; a first upper bridge switching tube 202; a first lower bridge switching tube 203; a first heating coil 204; a first pair of

resonant capacitors

205, 206; a first half-bridge midpoint voltage detection module 207;

a second heating module 300; a second driving module 301; a second upper bridge switching tube 302; a second lower bridge switching tube 303; a second heating coil 304; a second pair of

resonant capacitors

305, 306; a second half-bridge midpoint voltage detection module 307;

Zero crossing detection module 101.

Detailed Description

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.

An electromagnetic heating apparatus, a power control method thereof, and a power control device 100 according to an embodiment of the present invention are described below with reference to the accompanying drawings.

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

A power control method of an electromagnetic heating apparatus according to an embodiment of the first aspect of the present invention and a power control device 100 of an electromagnetic heating apparatus according to an embodiment of the second aspect of the present invention are described below with reference to fig. 1 to 10.

As shown in fig. 1, a power control apparatus 100 of an electromagnetic heating device includes: a determination module 10 and a power control module 20. The determining module 10 is configured to obtain an input power of each heating module 50 when determining that the plurality of heating modules 50 of the electromagnetic heating apparatus operate simultaneously, and determine a type of a corresponding heating module 50 according to the input power of each heating module 50 when the input powers of the plurality of heating modules 50 are different; the power control module 20 is configured to control the output power of each heating module 50 in a different power adjustment manner according to the type of each heating module 50.

As shown in fig. 2, the power control method of the electromagnetic heating apparatus includes steps S1 and S2.

Step S1: when it is determined that the plurality of heating modules 50 of the electromagnetic heating apparatus are simultaneously operated, the input power of each heating module 50 is acquired, and when there is a difference in the input power of the plurality of heating modules 50, the type of the corresponding heating module 50 is determined according to the input power of each heating module 50.

For example, in some embodiments, the type of heating module 50 includes a master heating module and a slave heating module. Determining the type of each heating module 50 based on the input power to the corresponding heating module 50 may include: the heating module 50 with the largest input power among the plurality of heating modules 50 is acquired, the heating module 50 with the largest input power is taken as a master heating module, and the rest heating modules 50 among the plurality of heating modules 50 are taken as slave heating modules. The heating modules 50 are thus classified according to the difference in input power, which may be the power input by the user to each heating module 50 according to the desired cooking function. Here, the number of the slave heating modules is one or more. When the electromagnetic heating device is operated by only one heating module 50, the heating module 50 can be used as a master heating module or a slave heating module to perform output power control in a corresponding power adjustment mode.

In one embodiment according to the present invention, as shown in fig. 3, the determining the type of each heating module 50 according to the input power of each heating module 50 in step S1 includes steps S11 and S12, which are specifically as follows:

step S11: it is determined whether the input power to any one of the heating modules 50 has changed. If not, the type of the heating module 50 and the control of the output power are not required to be judged, the method is exited, and the output power of the current heating module 50 is maintained; if yes, go to step S12.

Step S12: the heating module 50 with the largest input power among the plurality of heating modules 50 is acquired, the heating module 50 is used as a master heating module, and the rest heating modules 50 among the plurality of heating modules 50 are used as slave heating modules.

Thereby, the type of heating module 50 is determined.

As shown in fig. 2, step S2: the output power of each heating module 50 is controlled in a different power adjustment mode according to the type of the corresponding heating module 50. So that the output power of each heating module 50 is equal to its corresponding input power.

The output power is controlled by adopting different power adjustment modes for the heating modules 50 of different types, so that the consistency of the working frequencies of the heating modules 50 working simultaneously is facilitated, a series of synthesized frequencies are avoided from being generated by mixing various frequencies together in the working process, sharp and harsher noise caused by synthesizing difference frequency signals is avoided, and the use experience of a user is improved.

For example, in some embodiments, step S2: the output power of each heating module 50 is controlled in a different power adjustment manner according to the type of each heating module 50, including step S21 and step S22.

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

The power control device 100 of the electromagnetic heating apparatus outputs PWM (Pulse Width Modulation ) signals to control the plurality of heating modules 50, wherein the plurality of heating modules 50 are respectively a first heating module 200, a second heating module 300 and a third heating module 50 … …, and as shown in fig. 4, the first heating module 200 includes a first driving module 201, a first upper bridge switching tube 202, a first lower bridge switching tube 203, a first heating coil 204 and a first

resonant capacitor pair

205 and 206; the second heating module 300 includes a second driving module 301, a second upper bridge switching tube 302, a second lower bridge switching tube 303, a second heating coil 304, and a second pair of

resonant capacitors

305, 306; the power control device 100 of the … … electromagnetic heating equipment outputs PWM signals to the driving module, the driving module outputs complementary PWM signals to control the upper bridge switching tube and the lower bridge switching tube to be alternately conducted, the heating coil is controlled to output alternating current to generate an alternating magnetic field, the alternating magnetic field enables a metal pot placed on the heating coil to induce alternating eddy currents, and the alternating eddy currents enable the pot to heat, so that food can be heated.

The output power of the main heating module is controlled by adopting a frequency modulation power regulation mode, and the specific principle is as follows:

as shown in fig. 5, which shows a relationship diagram between the PWM frequency and the output power of the main heating module, the larger the PWM frequency, the smaller the output power in the frequency range of the inductive region (frequency f 0-f 1); the smaller the PWM frequency, the greater the output power.

Fig. 6 is a flowchart for controlling the output power of the main heating module by using a frequency modulated power regulation method. The method specifically comprises the following steps:

step S211: judging whether the input power of the main heating module is increased, if so, executing step S212; if not, executing step S214;

step S212: reducing the PWM frequency of the main heating module, and then performing step S213;

step S213: judging whether the output power of the current main heating module is equal to the input power, if so, ending the control of the output power of the main heating module, and exiting the method; if not, returning to execute S212;

step S214: increasing the PWM frequency of the main heating module, and then performing step S215;

step S215: judging whether the output power of the current main heating module is equal to the input power, if so, ending the control of the output power of the main heating module, and exiting the method; if not, the process returns to S214.

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

If the user adjusts the fire power to increase to 1500W, that is, adjusts the input power of the main heating module to 1500W, steps S212 and S213 are performed until the output power of the main heating module is equal to the input power, at this time, the power control device 100 outputs the PWM waveform of the main heating module as the W11 waveform in fig. 7, the output power is as the P11 (1500W) in fig. 5, and the corresponding PWM frequency is as the f11 (23 KHz) in fig. 5. It can be seen that the frequency of the PWM output by the power control device 100 is reduced from 25KHz (f 10) to 23KHz (f 11), and the output power is increased from 1000W to 1500W.

If the user adjusts the fire power to be reduced to 500W, that is, adjusts the input power of the main heating module to be 500W, steps S214 and S215 are performed until the output power of the main heating module is equal to the input power, at this time, the power control device 100 outputs the PWM waveform of the main heating module as the W12 waveform in fig. 7, the output power is as the P12 (500W) in fig. 5, and the corresponding PWM frequency is as the f12 (27 KHz) in fig. 5. It can be seen that the frequency of the PWM output by the power control device 100 increases from 25KHz (f 10) to 27KHz (f 12), resulting in a reduction of the output power from 1000W to 500W.

The output power of the main heating module is controlled in a frequency modulation power regulation mode, so that the output power of the main heating module can be regulated more quickly, the output power can be regulated to be equal to the input power, and the use experience of a user is improved. And the method is favorable for obtaining larger working power and meeting the larger output power adjusting range.

Step S22: when the current heating module 50 is determined to be the slave heating module, the output power of the slave heating module is controlled by adopting a power adjustment mode of duty cycle adjustment.

The specific principle of controlling the output power of the secondary heating module by adopting a power regulation mode of duty ratio is as follows:

fig. 8 is a graph showing the relationship between the duty cycle and the output power of the slave heating module in the case where the PWM frequency of the half-bridge switching 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 the PWM, the smaller the output power; the larger the duty cycle of the PWM, the larger the output power.

Fig. 9 is a flowchart of controlling the output power from the heating module by means of duty-cycle-modulated power regulation. The method specifically comprises the following steps:

step S221: judging whether the input power of the heating module is increased, if so, executing step S222; if not, executing step S224;

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

step S223: judging whether the output power of the current secondary heating module is equal to the input power, if so, ending the control of the output power of the secondary heating module, and exiting the method; if not, returning to execute S222;

step S224: decreasing the PWM duty cycle of the slave heating module, and then performing step S225;

step S225: judging whether the output power of the current secondary heating module is equal to the input power, if so, ending the control of the output power of the secondary heating module, and exiting the method; if not, the process returns to S224.

As shown in fig. 10, the power control device 100 outputs PWM waveforms of the master heating module and the slave heating module. Wherein W20 is a PWM waveform of the main heating module output by the power control device 100, and the duty ratio is 50%. The waveform W21 is a PWM waveform output from the heating module by the power control device 100, and the duty ratio is 30% (corresponding to P20 in fig. 8), and it can be seen that the PWM period of the master heating module (T10 in fig. 10) is equal to the PWM period of the slave heating module (T20 in fig. 1), and the PWM frequency of the slave heating module is the same as the PWM frequency of the master heating module, which is obtained by the formula frequency f=1/T.

If the user adjusts the power of the heating module from 500W to 600W, that is, adjusts the input power of the heating module to 600W, after executing steps S222 and S223 until the output power of the heating module is equal to the input power, the power control device 100 outputs the waveform of the PWM of the heating module as the waveform W22 in fig. 10, at this time, the high level time of the PWM of the heating module is increased from t21 to t22 in fig. 10, the corresponding duty ratio is increased from 30% to 40% in fig. 8, and the output power is increased from 500W to 600W.

If the user adjusts the power of the heating module from 500W to 400W, that is, adjusts the input power of the heating module to 400W, then after executing steps S224 and S225 until the output power of the heating module is equal to the input power, the power control device 100 outputs the waveform of the PWM of the heating module as the waveform W23 in fig. 10, at this time, the high level time of the PWM of the heating module is reduced from t21 to t23 in fig. 10, and the corresponding duty cycle is reduced from 30% to 30% in fig. 8, so as to reduce the output power from 500W to 400W.

The output power of the slave heating module is controlled by adopting a power adjustment mode of duty ratio adjustment, so that the PWM frequency of the slave heating module is unchanged in the process of power adjustment, thereby being beneficial to realizing the consistency of the PWM frequencies of the master heating module and the slave heating modules and the consistency of the PWM frequencies of a plurality of slave heating modules, and the PWM frequency of the output master heating module and the PWM frequency of the slave heating module of the power control device 100 are kept the same no matter how the output power of the master heating module and the output power of the slave heating module are changed, namely, the frequency difference of all output PWM is kept to be zero. Because the difference frequency signal is zero, sharp and harsh noise cannot be generated, and therefore the user experience effect is effectively improved.

According to the power control method of the electromagnetic heating device according to the first aspect of the present invention, by controlling the output power of the heating modules 50 of different types by adopting different power adjustment manners, it is beneficial to achieve the frequency consistency of the heating modules 50 that work simultaneously, so as to avoid the generation of a synthesized frequency by mixing multiple frequencies together in the working process, avoid the generation of sharp and harsh noise due to the synthesis of a difference frequency signal, and improve the use experience of users.

According to the power control device 100 of the electromagnetic heating apparatus according to the second aspect of the present invention, by controlling the output power by adopting different power adjustment manners for different types of heating modules 50, it is beneficial to achieve the frequency consistency of a plurality of heating modules 50 that work simultaneously, so as to avoid that multiple frequencies are mixed together to generate a composite frequency during the working process, avoid that a difference frequency signal is synthesized to generate sharp and harsh noise, and improve the use experience of users.

In the embodiment of the second aspect of the present invention, the method for determining the type of the corresponding heating module 50 by the determining module 10 and the method for controlling the output power of the corresponding heating module 50 by the power control module 20 in different power adjustment manners may refer to the power control method of the electromagnetic heating apparatus of the embodiment of the first aspect of the present invention, which is not described herein again.

According to some embodiments of the invention, step S21: the output power of the main heating module is controlled by adopting a frequency modulation power regulation mode, and the method comprises the following steps: and outputting a first PWM signal with a fixed duty ratio to the main heating module, and controlling the output power of the main heating module by adjusting the frequency of the first PWM signal. As shown in fig. 5, when the duty ratio of the first PWM signal is constant, the larger the frequency, the smaller the output power, and the smaller the frequency, the larger the output power. By fixing the duty ratio of the first PWM signal, only the frequency of the first PWM signal is regulated to regulate the output power of the main heating module, so that the power regulation is faster, and the power regulation method is simplified.

Further, step S22: the power regulation mode of adopting the duty ratio of adjustment controls the output power of the slave heating module, includes: the second PWM signal with fixed frequency is output to the secondary heating module, and the output power of the secondary heating module is controlled by adjusting the duty ratio of the second PWM signal. As shown in fig. 8, at a constant frequency of the second PWM signal, the larger the duty ratio, the larger the output power, and the smaller the duty ratio, the smaller the output power. The output power of the secondary heating module is regulated by only regulating the duty ratio of the second PWM signal through fixing the frequency of the second PWM signal, so that the frequencies of a plurality of secondary heating modules are always equal, and the generation of a difference frequency signal is effectively reduced.

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, so that the generation of a difference frequency signal is effectively avoided. For example, in some embodiments, after the frequency of the first PWM signal is adjusted to the output power of the master heating module being equal to the input power, the frequency of the second PWM signal is controlled to be equal to the frequency of the adjusted first PWM signal, and then the duty cycle of the second PWM signal is adjusted to the output power of the slave heating module being equal to the input power, thereby achieving frequency uniformity of the master heating module and the slave heating module. In addition, in the embodiment that the number of the secondary heating modules is multiple, the output powers of the multiple secondary heating modules can be controlled independently, the interference is avoided, the frequency consistency can be well maintained, and the power regulating 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% to adjust the output power of the slave heating module within a range less than or equal to the output power of the master heating module. For example, in some embodiments, the duty cycle of the second PWM signal may be adjusted to 0, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, etc. Wherein when the duty ratio of the second PWM signal is 0, heating is stopped from the heating module; when the duty ratio of the second PWM signal is 50%, the output power of the slave heating module is equal to the output power of the master heating module.

It should be noted that, when the number of heating modules 50 with the largest input power among the plurality of heating modules 50 is two or more, one of the heating modules 50 with the largest input power may be used as a master heating module, and the remaining heating modules 50 may be used as slave heating modules; alternatively, all the heating modules 50 with the maximum input power and the equal input power may be used as the master heating module, and the other heating modules 50 except for the several master heating modules may be used as the slave heating modules, so that the several master heating modules are controlled to input the first PWM signals with the same fixed duty ratio.

According to some embodiments of the present invention, when it is determined that the electromagnetic heating apparatus only has one heating module 50 to operate, the output power of the heating module 50 is controlled by using a frequency modulation power adjustment manner, so that the output power of the heating module 50 is controlled more quickly, and a larger range or higher output power can be output to meet the cooking requirement.

For example, in one embodiment, upon determining that only one heating module 50 of the electromagnetic heating apparatus is operating, the heating module 50 is controlled to input a first PWM signal having a fixed duty cycle of 50%, and the output power of the heating module 50 is controlled by adjusting the frequency of the first PWM signal.

A power control method of an electromagnetic heating apparatus according to an embodiment of the third aspect of the present invention and a power control device 100 of an electromagnetic heating apparatus according to an embodiment of the fourth aspect of the present invention are described below with reference to fig. 11 to 17.

Applicants found that when the duty cycle of the heating module 50 is smaller than a certain value, the half-bridge upper bridge switching tube enters a hard-on state from a soft-on state, the upper bridge switching tube is increased in loss and increased in temperature, the upper bridge switching tube is damaged, and the reliability of the electromagnetic heating device is reduced. Based on this, the invention also provides a power control method and a power control device 100 capable of reducing the temperature rise and loss of the upper bridge switching tube.

As shown in fig. 11, a power control apparatus 100 of an electromagnetic heating device according to a fourth aspect of the present invention may include: a power control module 20 and a decision module 30.

The power control module 20 is configured to determine a current duty cycle adjustment mode for driving the secondary heating module to perform a heating operation when controlling output power of the secondary heating module of the electromagnetic heating device by using a duty cycle adjustment power adjustment mode. The judging module 30 is configured to judge whether the upper bridge switching tube of the slave heating module is operating in the hard on state when 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. In addition, the power control module 20 is further configured to control the upper bridge switching tube and the lower bridge switching tube of the slave heating module by adopting a heating control manner with alternating complementary duty cycle and symmetrical duty cycle when the upper bridge switching tube of the slave heating module is operated in a hard on state

As shown in fig. 12, the power control method of the electromagnetic heating apparatus according to the embodiment of the third aspect of the present invention may include steps S3, S4, and S5. The method comprises the following steps:

step S3: when the output power of the auxiliary heating module of the electromagnetic heating equipment is controlled by adopting a duty ratio adjusting power adjusting mode, the current duty ratio adjusting mode for driving the auxiliary heating module to perform heating work is determined.

The slave heating module may be a heating module 50 having a non-maximum input power from among the plurality of heating modules 50, in other words, a heating module 50 having a relatively smaller input power from among the plurality of heating modules 50. For example, the method for determining the slave heating module among the plurality of heating modules 50 may refer to the power control method of the electromagnetic heating apparatus according to the embodiment of the first aspect of the present invention, and the entire content of the power control method according to the embodiment of the first aspect of the present invention may be applied to the power control method of the electromagnetic heating apparatus according to the embodiment of the third aspect of the present invention, and the details and advantages thereof will not be described herein.

Step S4: when the current duty ratio adjusting mode for driving the secondary heating module to perform heating operation is the complementary duty ratio continuous adjusting mode, judging whether an upper bridge switching tube of the secondary heating module works in a hard on state or not.

The switching tube has small loss and low temperature rise in a soft-on state, and is an ideal working state. The switch tube is in a hard on state and has large loss and high temperature. In general, when the duty ratio of the PWM signal is greater than a certain value, the upper bridge switching tube and the lower bridge switching tube operate in a soft-on state. However, when the duty ratio is smaller than a certain value, the upper bridge switching tube enters a hard-on state from a soft-on state. Therefore, whether the upper bridge switching tube of the heating module works in a hard on state or not is determined, and the upper bridge switching tube is controlled accordingly, so that the excessive loss and the excessive temperature rise of the upper bridge switching tube are avoided.

For example, in some embodiments, step S4: the judging whether the upper bridge switching tube of the slave heating module works in the hard on state or not may include steps S41 and S42, specifically as follows:

step S41: and judging whether the duty ratio of the PWM signal of the upper bridge switching tube is smaller than a preset value.

Step S42: and if the duty ratio of the PWM signal of the upper bridge switching tube is smaller than a preset value, determining that the upper bridge switching tube works in a hard on state.

Here, the preset value may be flexibly set according to actual situations, for example, in some specific embodiments, the preset value may be 30%, and if the duty ratio of the PWM signal of the upper bridge switching tube is 20%,20% is less than 30%, it is determined that the upper bridge switch works in the hard on state.

For another example, in some embodiments, step S4: the judging whether the upper bridge switching tube of the slave heating module works in the hard on state or not may include steps S43, S44 and S45, which are specifically as follows:

step S43: detecting midpoint voltage between an upper bridge switching tube and a lower bridge switching tube of the secondary heating module;

step S44: determining whether the voltage difference between the collector and the emitter of the upper bridge switching tube is larger than a preset voltage threshold value according to the midpoint voltage;

step S45: and when the voltage difference between the collector and the emitter of the upper bridge switching tube is larger than a preset voltage threshold value, determining that the upper bridge switching tube works in a hard on state.

Here, the preset voltage threshold may be set according to actual conditions, for example, the preset voltage threshold may be 0V. When the switching tube is conducted, if the voltage difference between the collector and the emitter of the switching tube is less than or equal to 0V, the switching tube is called a soft-on state. Conversely, if the collector-emitter voltage difference of the switching tube is greater than 0V, it is referred to as a hard-on state.

The power control device 100 of the electromagnetic heating apparatus outputs PWM signals to control the plurality of heating modules 50, and the plurality of heating modules 50 are respectively a first heating module 200 and a second heating module 300 … … the electromagnetic heating apparatus further comprises a first half-bridge midpoint voltage detection module 207 and a second half-bridge midpoint voltage detection module 307 … … which are arranged in one-to-one correspondence with the plurality of heating modules 50

As shown in fig. 13, the first heating module 200 includes a first driving module 201, a first upper bridge switching tube 202, a first lower bridge switching tube 203, a first heating coil 204, and a first

resonant capacitor pair

205, 206, and the first half-bridge midpoint voltage detection module 207 is configured to detect whether the first upper bridge switching tube 202 is in a hard-on state or a soft-on state; the second heating module 300 includes a second driving module 301, a second upper bridge switching tube 302, a second lower bridge switching tube 303, a second heating coil 304, and a second

resonant capacitor pair

305, 306, where the second half-bridge midpoint voltage detection module 307 is configured to detect whether the second upper bridge switching tube 302 is in a hard-on state or a soft-on state; … …

The following description will take the second heating module 300 as an example of the slave heating module.

Fig. 14 shows an operational waveform of the second heating module 300. W10 is a driving waveform of the gate (g 1) of the second upper bridge switching tube 302, W11 is a driving waveform of the gate (g 2) of the second lower bridge switching tube 303, and W12 is a voltage waveform of the second half bridge midpoint (g 3).

At time t11, when the PWM signal duty ratio is greater, the second upper bridge switching tube 302 is turned on, the second half-bridge midpoint voltage detection module 307 collects the midpoint voltage signal and sends the midpoint voltage signal to the power control device 100, the power control device 100 detects that the voltage of the second half-bridge midpoint voltage (g 3) is at the high level 310V and equal to the supply voltage (VC 2), the voltage difference between the collector and the emitter of the second upper bridge switching tube 302 is equal to 0V, and the power control device 100 determines that the second upper bridge switching tube 302 works in the soft-on state. At time t12, when the PWM signal duty ratio is larger, the second lower bridge switching tube 303 is turned on, and the power control device 100 detects that the voltage of the midpoint voltage (g 3) of the second half bridge is 0V, which is equal to the ground voltage, and then the voltage difference between the collector and the emitter of the second lower bridge switching tube 303 is equal to 0V, and the power control device 100 determines that the second lower bridge switching tube 303 works in the soft-on state. Under the condition, the loss of the upper bridge switching tube and the lower bridge switching 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 half-bridge upper bridge switching transistor may enter the hard on state from the soft on state. With continued reference to fig. 14, at time t13, when the PWM signal duty ratio is smaller and the second upper bridge switching tube 302 is turned on, the power control device 100 detects that the voltage of the midpoint voltage (g 3) of the second half bridge is 0V at low level and the supply voltage VC2 is 310V, and then the voltage difference between the collector and the emitter of the second upper bridge switching tube 302 is equal to 310V, and the power control device 100 determines that the second upper bridge switching tube 302 is operated in the hard-on state. In this case, the second upper bridge switching tube 302 is greatly lost, and the temperature rises, which seriously causes damage to the second upper bridge switching tube 302.

Because the half-bridge circuit has two switching tubes, an upper bridge switching tube and a lower bridge switching tube, the two switching tubes can have four working states:

first, the upper bridge switching tube is turned on, and the lower bridge switching tube is turned off, as shown in a T1 period in fig. 14;

second, the upper bridge switching tube is turned off, and the lower bridge switching tube is turned on, as shown in a T2 period in fig. 14;

third, the upper bridge switching tube and the lower bridge switching tube are simultaneously turned off as shown in d1 and d2 periods in fig. 14;

Fourth, the upper and lower switching tubes are simultaneously turned on, which causes a short circuit of the power supply, resulting in permanent damage to the switching tubes, and thus the switching tubes must be prevented from operating in this state.

Since the PWM driving signal at the gate of the switching tube is switched from high level to low level, the current flowing through the collector and emitter of the switching tube is not turned off immediately, i.e. the switching tube is not turned off from on to off instantaneously, and a certain time (about 0.5 us) is required to turn off completely. Therefore, in the half-bridge circuit, during the period when any one of the switching transistors is turned off and switched to the other switching transistor is turned on, a period (about 2 us) is required for simultaneously turning off two switching transistors for driving signals, as shown in d1 and d2 periods in fig. 14, so that the two switching transistors are operated in the third operating state, and the upper bridge switching transistor and the lower bridge switching transistor are prevented from being short-circuited and directly connected, thereby improving the service life and the safety, and the period is called dead time (dead time).

The duty ratio refers to the ratio of the length of the high level time to the length of the entire period within one period of the PWM signal. As shown in fig. 14, T1 is a high time period, T3 is a PWM period, and the duty ratio is equal to T1/T3.

For a half-bridge circuit with two switching tubes, the PWM signals of the upper bridge switching tube and the PWM signals of the lower bridge switching tube may have the following two modes:

one is a complementary duty ratio mode, which means that in one PWM period, the dead time is removed, and the level of the PWM signal of the upper bridge switching tube and the level of the PWM signal of the lower bridge switching tube are in opposite relation in other periods, and the condition that the upper bridge switching tube and the lower bridge switching tube are simultaneously conducted is avoided. For example, as shown in fig. 16, T13 is one PWM period, the dead time d1 and d2 are removed, and in other periods, the period T11 is the upper bridge switching transistor high level, and the lower bridge switching transistor low level; and in the T12 period, the upper bridge switching tube is at a low level, and the lower bridge switching tube is at a high level.

The other is a symmetrical duty ratio mode, which means that in one PWM period, the on time of the upper bridge switching tube is equal to the on time of the lower bridge switching tube, and the level of the PWM signal of the upper bridge switching tube and the level of the PWM signal of the lower bridge switching tube are in opposite relation. As shown in fig. 16, T23 is a PWM period, and the on time T21 of the upper bridge switching tube is equal to the on time T22 of the lower bridge switching tube, so there may be a period of time, where the PWM of the upper bridge switching tube and the PWM of the lower bridge switching tube are both in a low level state, for example, in the period Ta in fig. 16, the upper bridge switching tube and the lower bridge switching tube are in an off state.

The zero crossing time refers to the time when the ac power supply voltage crosses zero, as shown in fig. 15, the W20 waveform is a half-bridge power supply (VC 1, VC2 shown in fig. 13), where Z10, Z11, Z12, etc. are all zero crossing time marks.

According to some embodiments of the invention, in step S4, it is determined that the current duty cycle adjustment mode for driving the heating operation from the heating module is a complementary duty cycle continuous adjustment mode. The continuous adjustment mode of the complementary duty ratio means that in two continuous adjacent PWM signal periods, the upper bridge switching tube and the lower bridge switching tube are heated with the same duty ratio, and in one PWM period, namely in a time period between two zero crossing moments, the upper bridge switching tube and the lower bridge switching tube work in the complementary duty ratio modes, and the electric levels are in opposite relation. As shown in fig. 15, in the TM1 period of the W21 waveform, both the upper bridge switching tube and the lower bridge switching tube operate in the complementary duty cycle mode, the period M1 between the adjacent two zero crossing times thereof, and the developed waveform thereof is shown as the period M1 in fig. 16. When the upper bridge switching tube of the secondary heating module works in a soft-on state, the output power is controlled by adopting a complementary duty ratio continuous adjustment mode.

As shown in fig. 12, step S5: and if the upper bridge switching tube of the slave heating module works in a hard on state, the upper bridge switching tube and the lower bridge switching tube are controlled by adopting a heating control mode of alternating complementary duty ratio and symmetrical duty ratio.

The heating control mode of the complementary duty ratio-symmetrical duty ratio alternation refers to alternately outputting the complementary duty ratio mode and the symmetrical duty ratio mode by taking a time period between two zero crossing moments as a unit time, namely taking one PWM signal period as a unit time. As in TM2 period in fig. 15, the PWM signal of the complementary duty ratio mode is output in M1 period, and the PWM signal of the symmetrical duty ratio mode is output in M2 period. The M1 period expansion waveform is shown as M1 period in fig. 16, and the M2 period expansion waveform is shown as M2 period in fig. 16, and the on time T21 of the upper bridge switching tube is equal to the on time T22 of the lower bridge switching tube.

The heating is controlled by a heating control mode with alternating complementary duty ratio-symmetrical duty ratio, so that the upper bridge switching tube is prevented from being in a hard-on state for a long time, in other words, after the upper bridge switching tube and the lower bridge switching tube are controlled by the heating control mode with alternating complementary duty ratio-symmetrical duty ratio, the hard-on state of the single upper bridge switching tube is improved to the alternately hard-on state of the upper bridge switching tube and the lower bridge switching tube, and the heat generated by hard-on is independently born by the upper bridge switching tube and is jointly shared by the upper bridge switching tube and the lower bridge switching tube, so that the temperature rise of the switching tube is reduced by half, and the service life and the reliability of products are improved.

For example, in some embodiments, the control of the upper bridge switching tube and the lower bridge switching tube in the heating control manner with the complementary duty cycle-symmetrical duty cycle alternation in the step S5 may include steps S51-S54:

step S51: counting zero crossing points of an input alternating current power supply of the electromagnetic heating equipment;

step S52: determining whether the zero crossing count value is an odd value;

step S53: when the zero crossing count value is an odd value, PWM signals with symmetrical duty ratios are output to an upper bridge switching tube and a lower bridge switching tube so that the heating module can perform heating operation;

step S54: when the zero crossing count value is an even value, PWM signals with complementary duty ratios are output to the upper bridge switching tube and the lower bridge switching tube so that the heating module can perform heating operation.

The zero crossing point of the input alternating current power supply refers to the moment when the alternating current power supply voltage crosses zero. The zero-crossing detection module 101 may generate a zero-crossing signal when the ac power source is at a zero-crossing point and input the zero-crossing signal to the power control device 100, and the power control device 100 counts the zero-crossing point after detecting the zero-crossing signal, for example, the power control device 100 may include a zero-crossing counter, and the zero-crossing counter counts the zero-crossing point according to the zero-crossing signal, so that the power control device 100 controls whether to output a PWM signal with a symmetrical duty cycle or a PWM signal with a complementary duty cycle to the upper bridge switching tube and the lower bridge switching tube when the next zero-crossing signal arrives.

Fig. 15 shows waveforms of operation corresponding to the complementary duty cycle continuous adjustment mode and the complementary duty cycle-symmetrical duty cycle alternating heating control mode. Fig. 16 is a diagram showing the operation waveforms of the PWM signal of the complementary duty ratio and the PWM signal of the symmetrical duty ratio.

In fig. 15, the W20 waveform is a half-bridge power supply (VC 1, VC 2) voltage waveform, and Z10, Z11, Z12, etc. are zero crossing marks of an input ac power supply of the electromagnetic heating apparatus. In the period D10-D14 of the W21 waveform, the duty ratio of the upper bridge switching tube and the lower bridge switching tube is not changed, and the M1 stage working waveform shown in FIG. 16 corresponds to a complementary duty ratio continuous adjustment mode. The switching process of M1 and M2 in the D15-D112 period shown in fig. 15, and the switching tube operation waveforms in the M1 and M2 periods shown in fig. 16 correspond to the heating control mode of complementary duty cycle-symmetrical duty cycle alternation.

As shown in fig. 15, assuming that the duty ratio of the current PWM signal is 20%, before time t11, the power control device 100 adopts a complementary duty ratio continuous adjustment mode, and the upper bridge switching tube operates at 20% duty ratio, as shown in the M1 period of W30 in fig. 16; the lower bridge switching tube operates at 80% duty cycle as shown in fig. 16 for the M1 period of W31.

At time t11, the power control device 100 detects that the upper bridge switching tube is operated in the hard-on state, switches to the heating control mode in which the complementary duty ratio and the symmetrical duty ratio alternate, clears the zero-crossing counter, and makes the zero-crossing count value (CNT) zero. At the time of the zero crossing point Z15, the power control device 100 performs the method as shown in fig. 17, and after the zero crossing counter performs the 1-adding 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 switching tube operates with a duty cycle of 30%, as shown in the M2 period of W30 in fig. 16; the lower bridge switching tube operates at 30% duty cycle as shown in fig. 16 for the M2 period of W31. As can be seen from fig. 15, when the upper bridge switching tube is turned on (time t 21), the voltage difference between the collector and the emitter of the upper bridge switching tube is zero volt, the upper bridge switching tube is operated in a soft-on state, and when the lower bridge switching tube is turned on (time t 22), the voltage difference between the collector and the emitter of the lower bridge switching tube is 310V, and the upper bridge switching tube is operated in a hard-on state. The upper bridge switching tube has small loss and low temperature rise, and the lower bridge switching tube has large loss and high temperature rise.

At the next zero crossing point time Z16, the power control device 100 performs the method as shown in fig. 17, after the zero crossing counter performs the 1-adding operation, the value of CNT is 2, which is an even value, and the power control device 100 outputs a PWM signal with a complementary duty cycle, that is, the upper bridge switching tube operates with a duty cycle of 20%, as shown in the M1 period of W30 in fig. 16; the lower bridge switching tube operates at 80% duty cycle as shown in fig. 16 by the M1 period of W31. As can be seen from fig. 15, when the upper bridge switching tube is turned on (time t 11), the voltage difference between the collector and the emitter of the upper bridge switching tube is 310V, the upper bridge switching tube is operated in a hard-on state, and when the lower bridge switching tube is turned on (time t 12), the voltage difference between the collector and the emitter of the lower bridge switching tube is zero volt, and the upper bridge switching tube is operated in a soft-on state. The upper bridge switching tube has large loss and low temperature rise, and the lower bridge switching tube has small loss and low temperature rise.

Therefore, after a heating control mode of alternating complementary duty ratio and symmetrical duty ratio is adopted, the upper bridge switching tube works in a hard on state in a complementary duty ratio mode, and the lower bridge switching tube works in a hard on state in a symmetrical duty ratio mode. The complementary duty ratio and the symmetrical duty ratio are alternately carried out, so that the upper bridge switching tube and the lower bridge switching tube alternately work in a hard on state, heat generated by hard on is shared together, the temperature rise of the upper bridge switching tube is reduced by half, the phenomenon that the temperature rise is too high due to the fact that the upper bridge switching tube is in the hard on state for a long time is avoided, and the service life and reliability of electromagnetic heating equipment are improved.

According to some embodiments of the present invention, before the power adjustment manner of the duty cycle is adopted to control the output power of the slave heating module of the electromagnetic heating device in step S1, determining the master heating module and the slave heating module is further included, and the determining method may refer to the power control method of the electromagnetic heating device according to the embodiment of the first aspect of the present invention, which is not described herein again.

According to the power control method of the electromagnetic heating equipment, when the upper bridge switching tube of the heating module works in the hard on state, the upper bridge switching tube and the lower bridge switching tube are controlled in a heating control mode of alternating complementary duty ratio and symmetrical duty ratio, so that the upper bridge switching tube and the lower bridge switching tube work in the hard on state alternately, heat generated by the hard on is shared together, the temperature rise of the upper bridge switching tube is reduced, the upper bridge switching tube is prevented from being damaged due to long-time working in the hard on state, and the service life and the reliability of the electromagnetic heating equipment are improved.

According to the power control device 100 of the electromagnetic heating apparatus according to the fourth aspect of the present invention, when the upper bridge switching tube of the heating module is operated in the hard on state, the upper bridge switching tube and the lower bridge switching tube are controlled by adopting a heating control mode of alternating complementary duty ratio-symmetrical duty ratio, so that the upper bridge switching tube and the lower bridge switching tube alternately operate in the hard on state, share heat generated by the hard on together, reduce temperature rise of the upper bridge switching tube, avoid damage caused by long-time operation of the upper bridge switching tube in the hard on state, and improve service life and reliability of the electromagnetic heating apparatus.

In the fourth embodiment of the present invention, the method for controlling the output power of the secondary heating module by the power control module 20 in the duty cycle adjusting manner, the method for determining the current duty cycle adjusting manner for driving the secondary heating module to perform the heating operation, the method for determining whether the upper bridge switching tube of the secondary heating module is operated in the hard on state by the determining module 30, and the method for controlling the upper bridge switching tube and the lower bridge switching tube by the power control module 20 in the complementary duty cycle-symmetrical duty cycle alternating heating control manner may refer to the power control method of the electromagnetic heating apparatus according to the third embodiment of the present invention, which is not described herein.

A computer-readable storage medium according to an embodiment of the fifth aspect of the present invention has stored thereon a power control program of an electromagnetic heating apparatus, which when executed by a processor, implements a power control method of an electromagnetic heating apparatus as in the embodiment of the first aspect of the present invention, or implements a power control method of an electromagnetic heating apparatus as in the embodiment of the third aspect of the present invention.

Since the power control method of the electromagnetic heating apparatus according to the embodiment of the first aspect of the present invention has the above advantageous technical effects, the computer readable storage medium according to the fifth aspect of the present invention stores the power control program which when executed by the processor implements the power control method described in the above embodiment, and by controlling the output power to the different types of heating modules 50 by using different power adjustment manners, it is advantageous to implement the frequency consistency of the plurality of heating modules 50 that operate simultaneously, thereby avoiding the mixing of multiple frequencies together to generate a synthesized frequency during operation, avoiding the generation of sharp and harsh noise due to the synthesis of a difference frequency signal, and improving the user experience.

Since the power control method of the electromagnetic heating apparatus according to the third aspect of the present invention has the above advantageous technical effects, the computer readable storage medium according to the fifth aspect of the present invention, which stores the power control program when executed by the processor, implements the power control method described in the above embodiment, controls the upper bridge switching tube and the lower bridge switching tube by adopting a heating control manner of alternating complementary duty cycle-symmetrical duty cycle when the upper bridge switching tube of the heating module is operated in the hard on state, so that the upper bridge switching tube and the lower bridge switching tube are alternately operated in the hard on state to share heat generated by the hard on together, reduces the temperature rise of the upper bridge switching tube, avoids the upper bridge switching tube from being damaged due to long-time operation in the hard on state, and improves the service life and reliability of the electromagnetic heating apparatus.

An electromagnetic heating apparatus according to an embodiment of the sixth aspect of the present invention includes a memory, a processor, and a power control program of the electromagnetic heating apparatus stored on the memory and executable on the processor, and when the processor executes the power control program, the power control method of the electromagnetic heating apparatus as the embodiment of the first aspect of the present invention is implemented, or the power control method of the electromagnetic heating apparatus as the embodiment of the third aspect of the present invention is implemented.

Since the power control method of the electromagnetic heating apparatus according to the embodiment of the first aspect of the present invention has the above-mentioned beneficial technical effects, the electromagnetic heating apparatus according to the sixth aspect of the present invention, by controlling the output power by using different power adjustment modes for different types of heating modules 50, is beneficial to realizing the frequency consistency of a plurality of heating modules 50 that work simultaneously, thereby avoiding that a plurality of frequencies are mixed together to generate a synthesized frequency during the working process, avoiding that a difference frequency signal is synthesized to generate sharp and harsh noise, and is beneficial to improving the use experience of users.

Because the power control method of the electromagnetic heating device according to the embodiment of the third aspect of the present invention has the beneficial technical effects described above, according to the electromagnetic heating device of the sixth aspect of the present invention, the upper bridge switching tube and the lower bridge switching tube are controlled by adopting a heating control manner with alternating complementary duty ratio-symmetrical duty ratio when the upper bridge switching tube of the heating module is operated in the hard on state, so that the upper bridge switching tube and the lower bridge switching tube are alternately operated in the hard on state, and share heat generated by the hard on together, the temperature rise of the upper bridge switching tube is reduced, the upper bridge switching tube is prevented from being damaged due to long-time operation in the hard on state, and the service life and reliability of the electromagnetic heating device are improved.

Other constructions and operations of electromagnetic heating devices according to embodiments of the present invention are known to those of ordinary skill in the art and will not be described in detail herein.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. 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, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and additional implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order from that shown or discussed, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the embodiments of the present invention.

Logic and/or steps represented in the flowcharts or otherwise described herein, e.g., a ordered listing of executable instructions for implementing logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a 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 is printed, as the program may be electronically captured, via, for instance, optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory.

It is to be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above-described embodiments, the various steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. As with the other embodiments, if implemented in hardware, may be implemented using any one or combination of the following techniques, as is well known in the art: discrete logic circuits having logic gates for implementing logic functions on data signals, application specific integrated circuits having suitable combinational logic gates, programmable Gate Arrays (PGAs), field Programmable Gate Arrays (FPGAs), and the like.

Those of ordinary skill in the art will appreciate that all or a portion of the steps carried out in the method of the above-described embodiments may be implemented by a program to instruct related hardware, where the program may be stored in a computer readable storage medium, and where the program, when executed, includes one or a combination of the steps of the method embodiments.

In addition, each functional unit in the embodiments of the present invention may be integrated in one processing module, or each unit may exist alone physically, or two or more units may be integrated in one module. The integrated modules may be implemented in hardware or in software functional modules. The integrated modules may also be stored in a computer readable storage medium if implemented in the form of software functional modules and sold or used as a stand-alone product.

The above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, or the like. While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.

Claims

1. A power control method of an electromagnetic heating apparatus, comprising the steps of:

when the output power of the secondary heating module of the electromagnetic heating equipment is controlled by adopting a duty ratio adjusting power adjusting mode, determining a current duty ratio adjusting mode for driving the secondary heating module to perform heating work;

When the current duty ratio adjusting mode for driving the secondary heating module to perform heating work is a complementary duty ratio continuous adjusting mode, judging whether an upper bridge switching tube of the secondary heating module works in a hard on state or not;

if the upper bridge switching tube of the secondary heating module works in a hard on state, the upper bridge switching tube and the lower bridge switching tube of the secondary heating module are controlled by adopting a heating control mode with alternating complementary duty ratio and symmetrical duty ratio;

judging whether the upper bridge switching tube of the secondary heating module works in a hard on state or not, comprising:

judging whether the duty ratio of the PWM signal of the upper bridge switching tube is smaller than a preset value or not;

if the duty ratio of the PWM signal of the upper bridge switching tube is smaller than a preset value, determining that the upper bridge switching tube works in a hard-on state;

detecting the midpoint voltage between an upper bridge switching tube and a lower bridge switching tube of the secondary heating module;

judging whether the voltage difference between the collector and the emitter of the upper bridge switching tube is larger than a preset voltage threshold value or not according to the midpoint voltage;

when the voltage difference between the collector and the emitter of the upper bridge switching tube is larger than a preset voltage threshold value, determining that the upper bridge switching tube works in a hard-on state;

The method for controlling the upper bridge switching tube and the lower bridge switching tube of the secondary heating module by adopting a heating control mode of alternating complementary duty ratio and symmetrical duty ratio comprises the following steps:

counting zero crossing points of an input alternating current power supply of the electromagnetic heating equipment;

judging whether the zero crossing point count value is an odd value or not;

when the zero crossing point count value is an odd value, PWM signals with symmetrical duty ratios are output to the upper bridge switching tube and the lower bridge switching tube so that the secondary heating module performs heating operation;

when the zero crossing point count value is an even value, PWM signals with complementary duty ratios are output to the upper bridge switching tube and the lower bridge switching tube so that the secondary heating module performs heating operation;

the complementary duty ratio is that in one PWM period, the dead time is removed, and the level of the PWM signal of the upper bridge switching tube and the level of the PWM signal of the lower bridge switching tube are in opposite relation; the symmetrical duty ratio refers to that in one PWM period, the level of the PWM signal of the upper bridge switching tube and the level of the PWM signal of the lower bridge switching tube are in opposite relation, and the conduction time of the upper bridge switching tube is equal to the conduction time of the lower bridge switching tube.

2. The power control method of an electromagnetic heating apparatus according to claim 1, further comprising, before controlling the output power of a slave heating module of the electromagnetic heating apparatus by means of duty-cycle-adjusted power adjustment:

and acquiring a heating module with the largest input power from a plurality of heating modules of the electromagnetic heating equipment, taking the heating module with the largest input power as a master heating module, and taking the rest heating modules from the plurality of heating modules as slave heating modules.

3. The power control method of an electromagnetic heating apparatus according to claim 2, wherein the output power of the main heating module is controlled by frequency-modulated power regulation.

4. A method of controlling power to an electromagnetic heating apparatus as claimed in claim 3, wherein controlling the output power of the main heating module by means of frequency modulated power regulation comprises:

and outputting a first PWM signal with a fixed duty ratio to the main heating module, and controlling the output power of the main heating module by adjusting the frequency of the first PWM signal.

5. The power control method of an electromagnetic heating apparatus according to claim 4, wherein controlling the output power of the slave heating module by means of power adjustment of a duty cycle comprises:

And outputting a second PWM signal with fixed frequency to the secondary heating module, and controlling the output power of the secondary heating module by adjusting the duty ratio of the second PWM signal.

6. A computer-readable storage medium, characterized in that a power control program of an electromagnetic heating apparatus is stored thereon, which power control program, when executed by a processor, implements the power control method of an electromagnetic heating apparatus as claimed in any one of claims 1-5.

7. An electromagnetic heating device comprising a memory, a processor and a power control program of the electromagnetic heating device stored on the memory and executable on the processor, the processor implementing the power control method of the electromagnetic heating device according to any one of claims 1-5 when executing the power control program.

8. A power control apparatus of an electromagnetic heating device for performing the power control method of an electromagnetic heating device according to any one of claims 1 to 5, comprising:

the power control module is used for determining a current duty ratio regulating mode for driving the secondary heating module to heat when the power regulating mode for regulating the duty ratio is adopted to control the output power of the secondary heating module of the electromagnetic heating equipment;

The judging module is used for judging whether the upper bridge switching tube of the secondary heating module works in a hard on state or not when the current duty ratio adjusting mode for driving the secondary heating module to perform heating work is a complementary duty ratio continuous adjusting mode;

the power control module is also used for controlling the upper bridge switching tube and the lower bridge switching tube of the secondary heating module by adopting a heating control mode of alternating complementary duty ratio and symmetrical duty ratio when the upper bridge switching tube of the secondary heating module works in a hard on state.