CN106714351B - Method and system for determining zero-crossing conduction time and electromagnetic heating device - Google Patents

Abstract

The present invention provides a method for determining a zero-crossing on-time, a determining system, and an electromagnetic heating device, wherein the method for determining the zero-crossing on-time includes: after applying a first electrical load signal to the collector Obtain the sampling signal of the base within the specified time; determine whether there is a zero-crossing conduction signal according to the sampling signal; when it is determined that the zero-crossing conduction signal occurs, determine the zero-crossing conduction signal duration to complete the process of determining the zero-crossing on-time. Through the technical solution of the present invention, the electromagnetic heating device can be matched with a variety of cooking utensils, and at the same time, the cooking utensils are heated in an optimal working mode, thereby improving cooking efficiency, reducing power consumption, and improving user experience.

Description

Determination method, determination system and electromagnetic heating device of zero-crossing on-time

technical field

The invention relates to the technical field of household appliances, and more particularly, to a method for determining a zero-crossing on-time, a system for determining the zero-crossing on-time, and an electromagnetic heating device.

Background technique

In the related art, the driving scheme of the existing induction cooker IGBT (Insulated Gate Bipolar Transistor, insulated gate bipolar transistor) is solidified in the program of the controller. When working, find the driving scheme in the program by looking up the table to control the induction cooker for heating. For commonly used cookware and the parameters have not changed, it can usually match the working time under the corresponding power better, but for the material parameters of the less frequently used cookware and the material parameters of the general cookware have a large deviation, it is difficult to pass Looking up the table to obtain the driving scheme in the program, the cookware cannot be well compatible, resulting in a relatively large output power deviation and poor product reliability.

Therefore, how to determine the zero-crossing conduction time of the IGBT and then determine the heating mode of different cookware has become a technical problem to be solved urgently.

SUMMARY OF THE INVENTION

The present invention aims to solve at least one of the technical problems existing in the prior art.

Therefore, an object of the present invention is to propose a new method for determining the zero-crossing on-time.

Another object of the present invention is to provide a system for determining the zero-crossing on-time.

Another object of the present invention is to provide an electromagnetic heating device.

In order to achieve the above object, according to an embodiment of the first aspect of the present invention, a method for determining a zero-crossing on-time is proposed, which includes: within a specified time period after the first electrical load signal is applied to the collector, obtaining The sampling signal of the base electrode; according to the sampling signal, determine whether there is a zero-crossing conduction signal; when it is determined that the zero-crossing conduction signal occurs, determine the duration of the zero-crossing conduction signal to complete all Describe the process of determining the zero-crossing on-time.

According to the method for determining the zero on-time of the embodiment of the present invention, the zero-crossing on-time is determined by the sampling signal of the base, so that the accurate judgment of the zero-crossing on-time is realized, and at the same time, it is determined that the zero-crossing on-time can be triggered Therefore, the reliability of the IGBT is improved, so that it can work in the zero-crossing conduction state as much as possible, thereby saving power consumption and improving reliability.

Specifically, for electromagnetic heating devices such as induction cookers, the length of time that the front thyristor switch is turned on determines the energy intensity of the LC (coil disc and resonant capacitor) loop, and the energy intensity determines the amplitude of the LC oscillation, which in turn can predict the V _CE (set The voltage variation range of the voltage between the electrode and the emitter), and the V _CE (voltage between the collector and the emitter) voltage of the thyristor fluctuates when the thyristor LC (coil disc and resonant capacitor) naturally oscillates after it is turned off, among which, The amplitude of V _CE is relatively large, and the sampling signal of the base is positively correlated with V _CE . Therefore, the sampling signal of the base is used as the basis for judging zero-crossing conduction, which reduces the detection range and improves the reliability of the detection process.

Among them, by obtaining the sampling signal of the base of the thyristor switch, and inputting the obtained sampling signal into the AD conversion module (digital-to-analog conversion module) that comes with the single-chip microcomputer, or first passing the AD conversion chip and then inputting the obtained signal to the single-chip computer, the simulation is realized. The conversion between the signal and the digital signal, and the obtained digital signal is directly assigned to the program, so that the microcontroller can quickly determine whether there is a zero-crossing conduction point, that is, the electrical signal of the trigger point changes from zero or negative to positive. The MCU identifies the zero-crossing turn-on point, and compares the self-resonant voltage after turn-off with the set reference voltage, allowing the MCU to judge and automatically find the optimal zero-crossing on-time of the thyristor switch. .

In addition, the method for determining the zero-crossing on-time provided according to the foregoing embodiments of the present invention also has the following additional technical features:

According to an embodiment of the present invention, preferably, within a specified time period after the first electrical load signal is applied to the collector, acquiring the sampling signal of the base includes the following specific steps: applying the first electrical load signal to the collector. After the first electrical load signal is applied, the signal of the base electrode is collected within a specified time when the application of the first electrical load signal is stopped, and the digital-to-analog conversion process is performed on the signal of the base electrode to obtain the sampled signal .

According to the method for determining the zero-crossing on-time of the embodiment of the present invention, by collecting the base signal within a specified time after the first electrical load signal stops supplying power to the base, the detection range is reduced and the reliability of the detection process is improved .

Specifically, when the sampling signal of the base of the thyristor switch is obtained, and the obtained sampling signal is input into the AD conversion module (digital-to-analog conversion module) that comes with the single-chip microcomputer, or the obtained signal is firstly input to the single-chip microcomputer through the AD conversion chip, and the The obtained digital signal is directly assigned to the program, so that the single-chip microcomputer can determine that there is a zero-crossing conduction point, that is, the point when the trigger voltage changes from zero to a positive value, so that the zero-crossing conduction time can be determined.

According to an embodiment of the present invention, preferably, judging whether a zero-crossing conduction signal occurs according to the sampling signal includes the following specific steps: judging whether the sampling signal is greater than or equal to a preset reference signal; When the signal is greater than or equal to the preset reference signal, it is determined that the zero-crossing conduction signal occurs.

According to the method for determining the zero-crossing on-time of the embodiment of the present invention, by judging whether the sampling signal is greater than or equal to the preset reference signal to determine the occurrence of the zero-crossing on-time signal, it is possible to quickly judge and automatically find the maximum value of the thyristor switch. Excellent zero-crossing on time, and then adjust the drive synchronization scheme according to the zero-crossing on time, that is, the matching process of the electromagnetic heating device and the heating mode of different cooking utensils is realized, and the power consumption is reduced.

According to an embodiment of the present invention, preferably, judging whether the sampling signal is greater than or equal to a preset reference signal includes the following specific steps: when it is judged that the sampling signal is smaller than the preset reference signal, determining that there is no such excessive A zero turn-on signal appears.

According to the method for determining the zero-crossing on-time according to the embodiment of the present invention, when it is determined that the sampling signal is smaller than the preset reference signal, it is determined that no zero-crossing on-time signal appears, which further ensures the determination of the zero-crossing on-time. Reliability and accuracy, and at the same time, it is convenient to improve the efficiency of detecting zero-crossing conduction signals.

According to an embodiment of the present invention, preferably, it further includes the following specific step: when it is determined that the zero-crossing conduction signal does not appear, after applying a second electrical load signal to the collector, stop applying the second electrical load signal. Within a specified time of the electrical load signal, the sampling signal of the base is obtained to obtain the corresponding sampling signal, so as to determine the zero-crossing on-time according to the sampling signal, wherein the second electrical load signal The amplitude of is greater than the amplitude of the first electrical load signal.

According to the method for determining the zero-crossing on time according to the embodiment of the present invention, when it is determined that no zero-crossing on-time signal occurs, after the second electrical load signal is applied to the collector and the second electrical load signal is greater than the first electrical load signal The amplitude of , improves the efficiency of detecting the zero-crossing conduction time, and then determines the optimal power of the electromagnetic heating device for heating different pots and saves power consumption.

According to an embodiment of the second aspect of the present invention, a system for determining a zero-crossing on-time is also proposed, comprising: an acquisition unit, configured to acquire, within a specified time period after a first electrical load signal is applied to the collector, a sampling signal of the base electrode; a judging unit for judging whether a zero-crossing conduction signal occurs according to the sampling signal; a determining unit for determining the zero-crossing conduction signal when it is determined that the zero-crossing conduction signal occurs The duration of the turn-on signal to complete the process of determining the zero-cross turn-on time.

According to the system for determining the zero-crossing on-time of the embodiment of the present invention, the zero-crossing on-time is determined by the sampling signal of the base electrode, so that the accurate judgment of the zero-crossing on-time is realized, and at the same time, it is determined that the zero-crossing on-time can be triggered. Therefore, the reliability of the IGBT is improved, so that it can work in the zero-crossing conduction state as much as possible, thereby saving power consumption and improving reliability.

Specifically, for electromagnetic heating devices such as induction cookers, the length of time that the front thyristor switch is turned on determines the energy intensity of the LC (coil disc and resonant capacitor) loop, and the energy intensity determines the amplitude of the LC oscillation, which in turn can predict the V _CE (set The voltage variation range of the voltage between the electrode and the emitter), and the V _CE (voltage between the collector and the emitter) voltage of the thyristor fluctuates when the thyristor LC (coil disc and resonant capacitor) naturally oscillates after it is turned off, among which, The amplitude of V _CE is relatively large, and the sampling signal of the base is positively correlated with V _CE . Therefore, the sampling signal of the base is used as the basis for judging zero-crossing conduction, which reduces the detection range and improves the reliability of the detection process.

Among them, by obtaining the sampling signal of the base of the thyristor switch, and inputting the obtained sampling signal into the AD conversion module (digital-to-analog conversion module) that comes with the single-chip microcomputer, or first passing the AD conversion chip and then inputting the obtained signal to the single-chip computer, the simulation is realized. The conversion between the signal and the digital signal, and the obtained digital signal is directly assigned to the program, so that the microcontroller can quickly determine whether there is a zero-crossing conduction point, that is, the electrical signal of the trigger point changes from zero or negative to positive. The MCU identifies the zero-crossing turn-on point, and compares the self-resonant voltage after turn-off with the set reference voltage, allowing the MCU to judge and automatically find the optimal zero-crossing on-time of the thyristor switch. .

According to an embodiment of the present invention, preferably, the acquisition unit further includes: an acquisition unit, configured to stop applying the specified first electrical load signal after applying the first electrical load signal to the collector. During the time, the signal of the base electrode is collected, and digital-to-analog conversion processing is performed on the signal of the base electrode to obtain the sampled signal.

According to the system for determining the zero-crossing on-time of the embodiment of the present invention, by collecting the base signal within a specified time after the first electrical load signal stops supplying power to the base, the detection range is reduced and the reliability of the detection process is improved .

Specifically, when the sampling signal of the base of the thyristor switch is obtained, and the obtained sampling signal is input into the AD conversion module (digital-to-analog conversion module) that comes with the single-chip microcomputer, or the obtained signal is firstly input to the single-chip microcomputer through the AD conversion chip, and the The obtained digital signal is directly assigned to the program, so that the single-chip microcomputer can determine that there is a zero-crossing conduction point, that is, the point when the trigger voltage changes from zero to a positive value, so that the zero-crossing conduction time can be determined.

According to an embodiment of the present invention, preferably, the determining unit is further configured to determine whether the sampling signal is greater than or equal to a preset reference signal; the determining unit is further configured to determine whether the sampling signal is greater than or equal to a preset reference signal. When the preset reference signal is used, it is determined that the zero-crossing conduction signal appears.

According to the system for determining the zero-crossing on time according to the embodiment of the present invention, by judging whether the sampling signal is greater than or equal to the preset reference signal to determine the occurrence of the zero-crossing on-time signal, it is possible to quickly determine and automatically find the maximum value of the thyristor switch. Excellent zero-crossing on time, and then adjust the drive synchronization scheme according to the zero-crossing on time, that is, the matching process of the electromagnetic heating device and the heating mode of different cooking utensils is realized, and the power consumption is reduced.

According to an embodiment of the present invention, preferably, the determining unit is further configured to, when it is determined that the sampling signal is smaller than the preset reference signal, determine that the zero-crossing on-signal does not appear.

According to the system for determining the zero-crossing on-time according to the embodiment of the present invention, when it is determined that the sampling signal is smaller than the preset reference signal, it is determined that no zero-crossing on-time signal appears, which further ensures that the zero-crossing on-time is determined. Reliability and accuracy, and at the same time, it is convenient to improve the efficiency of detecting zero-crossing conduction signals.

According to an embodiment of the present invention, preferably, the acquiring unit is further configured to, when it is determined that the zero-crossing conduction signal does not appear, after applying a second electrical load signal to the collector, stop applying the A sampling signal of the base is acquired within a specified time period of the second electrical load signal, so as to determine the zero-crossing on-time according to the sampling signal, wherein the amplitude of the second electrical load signal is greater than that of the first electrical load signal. The magnitude of an electrical load signal.

According to the system for determining the zero-crossing on time according to the embodiment of the present invention, when it is determined that no zero-crossing on-time signal occurs, after applying the second electrical load signal to the collector and the second electrical load signal is greater than the first electrical load signal The amplitude of , improves the efficiency of detecting the zero-crossing conduction time, and then determines the optimal power of the electromagnetic heating device for heating different pots and saves power consumption.

According to an embodiment of the third aspect of the present invention, an electromagnetic heating device is also provided, including the system for determining the zero-crossing on-time as described in any one of the above technical solutions.

Additional aspects and advantages according to the invention will be presented in the description which follows, in part, which will be apparent from the description, or learned by practice of the invention.

Description of drawings

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

1 shows a schematic flowchart of a method for determining a zero-crossing on-time according to an embodiment of the present invention;

2 shows a schematic block diagram of a system for determining zero-crossing on-time according to an embodiment of the present invention;

3 shows a structural block diagram of an electromagnetic heating device according to an embodiment of the present invention;

FIG. 4 shows a schematic flowchart of a control method of an electromagnetic heating device according to an embodiment of the present invention;

FIG. 5 shows a real-time test chart of electromagnetic heating control according to an embodiment of the present invention;

FIG. 6 shows a real-time test chart of electromagnetic heating control according to another embodiment of the present invention.

Detailed ways

In order to understand the above objects, features and advantages of the present invention more clearly, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments may be combined with each other in the case of no conflict.

Many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited by the specific implementation disclosed below. example limitations.

FIG. 1 shows a schematic flowchart of a method for determining a zero-crossing on-time according to an embodiment of the present invention.

As shown in FIG. 1 , the method for determining the zero-crossing on-time according to an embodiment of the present invention includes: Step 102 , within a specified time period after a first electrical load signal is applied to the collector, obtain the Sampling signal; Step 104, according to the sampling signal to determine whether there is a zero-crossing conduction signal; Step 106, when it is determined that the zero-crossing conduction signal occurs, determine the duration of the zero-crossing conduction signal to complete The process of determining the zero-crossing on-time.

According to the method for determining the zero on-time of the embodiment of the present invention, the zero-crossing on-time is determined by the sampling signal of the base, so that the accurate judgment of the zero-crossing on-time is realized, and at the same time, it is determined that the zero-crossing on-time can be triggered Therefore, the reliability of the IGBT is improved, so that it can work in the zero-crossing conduction state as much as possible, thereby saving power consumption and improving reliability.

Specifically, for electromagnetic heating devices such as induction cookers, the length of time that the front thyristor switch is turned on determines the energy intensity of the LC (coil disc and resonant capacitor) loop, and the energy intensity determines the amplitude of the LC oscillation, which in turn can predict the V _CE (set The voltage variation range of the voltage between the electrode and the emitter), and the V _CE (voltage between the collector and the emitter) voltage of the thyristor fluctuates when the thyristor LC (coil disc and resonant capacitor) naturally oscillates after it is turned off, among which, The amplitude of V _CE is relatively large, and the sampling signal of the base is positively correlated with V _CE . Therefore, the sampling signal of the base is used as the basis for judging zero-crossing conduction, which reduces the detection range and improves the reliability of the detection process.

Among them, by obtaining the sampling signal of the base of the thyristor switch, and inputting the obtained sampling signal into the AD conversion module (digital-to-analog conversion module) that comes with the single-chip microcomputer, or first passing the AD conversion chip and then inputting the obtained signal to the single-chip computer, the simulation is realized. The conversion between the signal and the digital signal, and the obtained digital signal is directly assigned to the program, so that the microcontroller can quickly determine whether there is a zero-crossing conduction point, that is, the electrical signal of the trigger point changes from zero or negative to positive. The MCU identifies the zero-crossing turn-on point, and compares the self-resonant voltage after turn-off with the set reference voltage, allowing the MCU to judge and automatically find the optimal zero-crossing on-time of the thyristor switch. .

In addition, the method for determining the zero-crossing on-time provided according to the foregoing embodiments of the present invention also has the following additional technical features:

According to an embodiment of the present invention, preferably, within a specified time period after the first electrical load signal is applied to the collector, acquiring the sampling signal of the base includes the following specific steps: applying the first electrical load signal to the collector. After the first electrical load signal is applied, the signal of the base electrode is collected within a specified time when the application of the first electrical load signal is stopped, and the digital-to-analog conversion process is performed on the signal of the base electrode to obtain the sampled signal .

According to the method for determining the zero-crossing on-time of the embodiment of the present invention, by collecting the base signal within a specified time after the first electrical load signal stops supplying power to the base, the detection range is reduced and the reliability of the detection process is improved .

Specifically, when the sampling signal of the base of the thyristor switch is obtained, and the obtained sampling signal is input into the AD conversion module (digital-to-analog conversion module) that comes with the single-chip microcomputer, or the obtained signal is firstly input to the single-chip microcomputer through the AD conversion chip, and the The obtained digital signal is directly assigned to the program, so that the single-chip microcomputer can determine that there is a zero-crossing conduction point, that is, the point when the trigger voltage changes from zero to a positive value, so that the zero-crossing conduction time can be determined.

According to an embodiment of the present invention, preferably, judging whether a zero-crossing conduction signal occurs according to the sampling signal includes the following specific steps: judging whether the sampling signal is greater than or equal to a preset reference signal; When the signal is greater than or equal to the preset reference signal, it is determined that the zero-crossing conduction signal occurs.

According to the method for determining the zero-crossing on-time of the embodiment of the present invention, by judging whether the sampling signal is greater than or equal to the preset reference signal to determine the occurrence of the zero-crossing on-time signal, it is possible to quickly judge and automatically find the maximum value of the thyristor switch. Excellent zero-crossing on time, and then adjust the drive synchronization scheme according to the zero-crossing on time, that is, the matching process of the electromagnetic heating device and the heating mode of different cooking utensils is realized, and the power consumption is reduced.

According to an embodiment of the present invention, preferably, judging whether the sampling signal is greater than or equal to a preset reference signal includes the following specific steps: when it is judged that the sampling signal is smaller than the preset reference signal, determining that there is no such excessive A zero turn-on signal appears.

According to the method for determining the zero-crossing on-time according to the embodiment of the present invention, when it is determined that the sampling signal is smaller than the preset reference signal, it is determined that no zero-crossing on-time signal appears, which further ensures the determination of the zero-crossing on-time. Reliability and accuracy, and at the same time, it is convenient to improve the efficiency of detecting zero-crossing conduction signals.

According to an embodiment of the present invention, preferably, it further includes the following specific step: when it is determined that the zero-crossing conduction signal does not appear, after applying a second electrical load signal to the collector, stop applying the second electrical load signal. Within a specified time of the electrical load signal, the sampling signal of the base is obtained to obtain the corresponding sampling signal, so as to determine the zero-crossing on-time according to the sampling signal, wherein the second electrical load signal The amplitude of is greater than the amplitude of the first electrical load signal.

According to the method for determining the zero-crossing on time according to the embodiment of the present invention, when it is determined that no zero-crossing on-time signal occurs, after the second electrical load signal is applied to the collector and the second electrical load signal is greater than the first electrical load signal The amplitude of , improves the efficiency of detecting the zero-crossing conduction time, and then determines the optimal power of the electromagnetic heating device for heating different pots and saves power consumption.

FIG. 2 shows a schematic block diagram of a system for determining the zero-crossing on-time according to an embodiment of the present invention.

As shown in FIG. 2 , the system 200 for determining the zero-crossing on-time according to an embodiment of the present invention includes: an obtaining unit 202, configured to obtain all the The sampling signal of the base; the determination unit 204 is used to determine whether there is a zero-crossing conduction signal according to the sampling signal; the determining unit 206 is used to determine the zero-crossing conduction signal when it is determined that the zero-crossing conduction signal occurs. The duration of the zero turn-on signal to complete the process of determining the zero-cross turn-on time.

According to the system for determining the zero-crossing on-time of the embodiment of the present invention, the zero-crossing on-time is determined by the sampling signal of the base electrode, so that the accurate judgment of the zero-crossing on-time is realized, and at the same time, it is determined that the zero-crossing on-time can be triggered. Therefore, the reliability of the IGBT is improved, so that it can work in the zero-crossing conduction state as much as possible, thereby saving power consumption and improving reliability.

Specifically, for electromagnetic heating devices such as induction cookers, the length of time that the front thyristor switch is turned on determines the energy intensity of the LC (coil disc and resonant capacitor) loop, and the energy intensity determines the amplitude of the LC oscillation, which in turn can predict the V _CE (set The voltage variation range of the voltage between the electrode and the emitter), and the V _CE (voltage between the collector and the emitter) voltage of the thyristor fluctuates when the thyristor LC (coil disc and resonant capacitor) naturally oscillates after it is turned off, among which, The amplitude of V _CE is relatively large, and the sampling signal of the base is positively correlated with V _CE . Therefore, the sampling signal of the base is used as the basis for judging zero-crossing conduction, which reduces the detection range and improves the reliability of the detection process.

Among them, by obtaining the sampling signal of the base of the thyristor switch, and inputting the obtained sampling signal into the AD conversion module (digital-to-analog conversion module) that comes with the single-chip microcomputer, or first passing the AD conversion chip and then inputting the obtained signal to the single-chip computer, the simulation is realized. The conversion between the signal and the digital signal, and the obtained digital signal is directly assigned to the program, so that the microcontroller can quickly determine whether there is a zero-crossing conduction point, that is, the electrical signal of the trigger point changes from zero or negative to positive. The MCU identifies the zero-crossing turn-on point, and compares the self-resonant voltage after turn-off with the set reference voltage, allowing the MCU to judge and automatically find the optimal zero-crossing on-time of the thyristor switch. .

According to an embodiment of the present invention, preferably, the acquisition unit 202 further includes: a collection unit 2022, configured to stop applying the first electrical load signal after applying the first electrical load signal to the collector The signal of the base electrode is collected within the specified time, and the digital-to-analog conversion process is performed on the signal of the base electrode to obtain the sampled signal.

According to the system for determining the zero-crossing on-time of the embodiment of the present invention, by collecting the base signal within a specified time after the first electrical load signal stops supplying power to the base, the detection range is reduced and the reliability of the detection process is improved .

Specifically, when the sampling signal of the base of the thyristor switch is obtained, and the obtained sampling signal is input into the AD conversion module (digital-to-analog conversion module) that comes with the single-chip microcomputer, or the obtained signal is firstly input to the single-chip microcomputer through the AD conversion chip, and the The obtained digital signal is directly assigned to the program, so that the single-chip microcomputer can determine that there is a zero-crossing conduction point, that is, the point when the trigger voltage changes from zero to a positive value, so that the zero-crossing conduction time can be determined.

According to an embodiment of the present invention, preferably, the determining unit 204 is further configured to determine whether the sampling signal is greater than or equal to a preset reference signal; the determining unit 206 is further configured to determine whether the sampling signal is greater than or equal to a preset reference signal. When it is equal to or equal to the preset reference signal, it is determined that the zero-crossing turn-on signal occurs.

According to the system for determining the zero-crossing on time according to the embodiment of the present invention, by judging whether the sampling signal is greater than or equal to the preset reference signal to determine the occurrence of the zero-crossing on-time signal, it is possible to quickly determine and automatically find the maximum value of the thyristor switch. Excellent zero-crossing on time, and then adjust the drive synchronization scheme according to the zero-crossing on time, that is, the matching process of the electromagnetic heating device and the heating mode of different cooking utensils is realized, and the power consumption is reduced.

According to an embodiment of the present invention, preferably, the determining unit 206 is further configured to, when it is determined that the sampling signal is smaller than the preset reference signal, determine that the zero-crossing on-signal does not appear.

According to the system for determining the zero-crossing on-time according to the embodiment of the present invention, when it is determined that the sampling signal is smaller than the preset reference signal, it is determined that no zero-crossing on-time signal appears, which further ensures that the zero-crossing on-time is determined. Reliability and accuracy, and at the same time, it is convenient to improve the efficiency of detecting zero-crossing conduction signals.

According to an embodiment of the present invention, preferably, the obtaining unit 202 is further configured to, when it is determined that the zero-crossing conduction signal does not appear, after the second electrical load signal is applied to the collector, stop applying the second electrical load signal. within the specified time of the second electrical load signal, obtain the sampling signal of the base, so as to determine the zero-crossing on time according to the sampling signal, wherein the amplitude of the second electrical load signal is greater than the The magnitude of the first electrical load signal.

According to the system for determining the zero-crossing on time according to the embodiment of the present invention, when it is determined that no zero-crossing on-time signal occurs, after applying the second electrical load signal to the collector and the second electrical load signal is greater than the first electrical load signal The amplitude of , improves the efficiency of detecting the zero-crossing conduction time, and then determines the optimal power of the electromagnetic heating device for heating different pots and saves power consumption.

FIG. 3 shows a structural block diagram of an electromagnetic heating device according to an embodiment of the present invention.

As shown in FIG. 3 , an electromagnetic heating device 300 according to an embodiment of the present invention includes: the system 200 for determining the zero-crossing on-time as described in any one of the above technical solutions.

FIG. 4 shows a schematic flow chart of a control method of an electromagnetic heating device according to an embodiment of the present invention.

As shown in FIG. 4 , a method for controlling an electromagnetic heating device according to an embodiment of the present invention includes: step 402 , a pot judgment procedure; step 404 , initial continuous heating (minimum PPG value); step 406 , turn off after working for 5ms Make it self-oscillate (at the power frequency voltage peak); Step 408, PPG is extended by a certain value; Step 410, determine whether a trigger signal is generated, if yes, then go to Step 412, if not (as shown in Figure 5), go to Step 408; Step 412, determine the zero-cross conduction time of the IGBT under the optimal PPG; Step 414, match the zero-cross conduction time with the type of the cookware; Step 416, determine the type of any power command obtained; Step 418, Low-power command control sub-flow; step 420, high-power command control sub-flow; step 422, reference power control sub-flow.

Specifically, in step 404, the electromagnetic heating device is controlled to perform heating under a preset heating time, and after the heating is completed, the electromagnetic heating device enters a self-resonance state, that is, the above-mentioned self-oscillation state, and the self-resonant voltage begins to vary with the self-resonance time. It increases and decreases continuously, so that the time recording is performed when the voltage is lower than the reference voltage, using the principle that the V _CE voltage of the IGBT follows the fluctuation when the LC (coil disc and resonant capacitor) self-oscillates after the induction cooker is shut down (the IGBT is turned off for a relatively long time). to fulfill. The length of time that the IGBT is turned on before it is turned off determines the energy intensity of the LC loop, and the energy intensity determines the amplitude of the LC oscillation, and the change range of V _CE can also be expected. When the IGBT is turned on for a certain amount of time before it is turned off, and the voltage fluctuation of V _CE is the lowest to a certain degree, the IGBT exhibits zero-crossing conduction, and the trigger signal 1 as shown in Figure 6 will also be generated, and the previous IGBTs were all super-leading On, of course, there will be hysteresis conduction if it is lower, record the start time from trigger signal 1 to the self-oscillation state to determine the reference heating time. If the self-resonant voltage of the IGBT is reduced to zero, the trigger signal does not appear 1, the control increases the duty cycle of the PPG and tests whether there is a trigger signal 1 in real time. The electromagnetic heating control scheme according to the present invention is to let the single-chip microcomputer identify the point of zero-crossing conduction, and record the time when the IGBT is turned on at this time. The time at which the IGBT is turned on at zero turn-on is different.

The technical solution of the present invention has been described in detail above with reference to the accompanying drawings. Considering the technical problem of how to determine the zero-crossing on-time of the IGBT and then determine the heating modes of different cookware, the present invention proposes a method for determining the zero-crossing on-time. , A determination system for zero-crossing on-time and an electromagnetic heating device enable the induction cooker to determine the zero-crossing on-time through the sampling signal of the base, so as to accurately judge the zero-crossing on-time, and at the same time determine the The load signal that triggers the zero-crossing conduction improves the reliability of the IGBT and makes it work in the zero-crossing conduction state as much as possible, thereby saving power consumption and improving reliability.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (9)

1. A method for determining a zero-crossing on-time, applicable to a thyristor switch, the thyristor switch comprising an emitter, a collector and a base, and the method for determining the zero-crossing on-time comprising: Acquire a sampling signal of the base within a specified time period after applying the first electrical load signal to the collector; Determine whether there is a zero-crossing conduction signal according to the sampling signal; When it is determined that the zero-crossing on-signal occurs, the duration of the zero-crossing on-signal is determined to complete the process of determining the zero-crossing on-time; When it is determined that the zero-crossing turn-on signal does not appear, after applying a second electrical load signal to the collector, the sampling signal of the base is acquired within a specified time period when the application of the second electrical load signal is stopped, to obtain the corresponding sampling signal, so as to determine the zero-crossing on-time according to the sampling signal; Wherein, the amplitude of the second electrical load signal is greater than the amplitude of the first electrical load signal. 2. The method for determining the zero-crossing on-time according to claim 1 , obtaining the sampling signal of the base within a specified time period after applying the first electrical load signal to the collector, comprising the following specific steps: After the first electrical load signal is applied to the collector, the signal of the base is collected within a specified time when the application of the first electrical load signal is stopped, and digital-to-analog conversion processing is performed on the signal of the base , to obtain the sampled signal. 3. The method for determining the zero-crossing on-time according to claim 1, judging whether there is a zero-crossing on-time signal according to the sampling signal, comprising the following specific steps: judging whether the sampling signal is greater than or equal to a preset reference signal; When it is determined that the sampling signal is greater than or equal to the preset reference signal, it is determined that the zero-crossing on signal occurs. 4. The method for determining the zero-crossing on-time according to claim 3, judging whether the sampling signal is greater than or equal to a preset reference signal, comprising the following specific steps: When it is determined that the sampling signal is smaller than the preset reference signal, it is determined that the zero-crossing on-signal does not appear. 5. A system for determining a zero-crossing on-time, suitable for a thyristor switch, the thyristor switch comprising an emitter, a collector and a base, the system for determining the zero-crossing on-time comprising: an acquisition unit, configured to acquire the sampling signal of the base within a specified time period after the first electrical load signal is applied to the collector; a judging unit for judging whether there is a zero-crossing conduction signal according to the sampling signal; a determining unit, configured to determine the duration of the zero-crossing on-time signal when it is determined that the zero-crossing on-time signal occurs, so as to complete the process of determining the zero-crossing on-time; The obtaining unit is further configured to obtain, when it is determined that the zero-crossing conduction signal does not appear, after applying the second electrical load signal to the collector, within a specified time period when the application of the second electrical load signal is stopped. a sampling signal of the base, so as to determine the zero-crossing on-time according to the sampling signal; Wherein, the amplitude of the second electrical load signal is greater than the amplitude of the first electrical load signal. 6. The system for determining zero-crossing on-time according to claim 5, wherein the acquiring unit further comprises: a collection unit, configured to collect the signal of the base within a specified time when the application of the first electrical load signal is stopped after applying the first electrical load signal to the collector, and to collect the signal of the base A digital-to-analog conversion process is performed to obtain the sampled signal. 7. The system for determining the zero-crossing on-time according to claim 5, wherein the judging unit is further used to judge whether the sampling signal is greater than or equal to a preset reference signal; The determining unit is further configured to, when determining that the sampling signal is greater than or equal to the preset reference signal, determine that the zero-crossing conduction signal occurs. 8 . The system for determining the zero-crossing on-time according to claim 7 , wherein the determining unit is further configured to, when it is determined that the sampling signal is smaller than the preset reference signal, determine that there is no zero-crossing on-time signal. 9 . Appear. 9 . An electromagnetic heating device, characterized in that , comprising: the system for determining the zero-crossing on-time according to any one of claims 5 to 8 . 10 .

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