CN106470506B - Electromagnetic heating system and switching-on control device and method of switch tube thereof - Google Patents
Electromagnetic heating system and switching-on control device and method of switch tube thereof Download PDFInfo
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- CN106470506B CN106470506B CN201510504038.7A CN201510504038A CN106470506B CN 106470506 B CN106470506 B CN 106470506B CN 201510504038 A CN201510504038 A CN 201510504038A CN 106470506 B CN106470506 B CN 106470506B
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Abstract
The invention discloses an electromagnetic heating system and a switching-on control device and method of a switching tube thereof, wherein the electromagnetic heating system comprises a resonance circuit and a power supply circuit, and the switching-on control device comprises: a first voltage dividing circuit for dividing the power supply voltage output by the power supply circuit to output a first voltage; the second voltage division circuit is used for dividing the collector voltage of the switching tube to output a second voltage; a comparison circuit for comparing the first voltage and the second voltage to output a comparison signal; the driving controller is used for acquiring the oscillation half cycle and the collector voltage reference point of the resonant circuit according to the comparison signal, calculating the time delay time according to the oscillation half cycle of the resonant circuit, and controlling the switching tube to be switched on again when the collector voltage of the switching tube oscillates to the collector voltage reference point, so that the switching tube can be controlled to be switched on at the lowest point of the collector voltage, the advance voltage can be reduced, the electromagnetic heating energy efficiency can be improved, the power resource can be saved, and the service life of a product can be prolonged.
Description
Technical Field
The invention relates to the technical field of electric appliances, in particular to a switching-on control device of a switching tube in an electromagnetic heating system, the electromagnetic heating system and a switching-on control method of the switching tube in the electromagnetic heating system.
Background
The electromagnetic heating system in the related art cannot accurately control the on and off of the switching tube. Theoretically, the switch tube should be turned on at the lowest point of the collector voltage, especially under the condition of advanced work, if the switch tube is not turned on at the lowest point of the collector voltage, the turn-on voltage of the switch tube is too high, the turn-on loss of the switch tube is large, energy is wasted, the service life of a product is shortened, and even the switch tube is broken down when serious, so that safety accidents are caused.
Disclosure of Invention
The present invention is directed to solving, at least in part, one of the technical problems in the related art. Therefore, an object of the present invention is to provide an apparatus for controlling turn-on of a switching tube in an electromagnetic heating system capable of controlling the switching tube to turn on at the lowest point of the collector voltage.
Another object of the present invention is to provide an electromagnetic heating system.
Another object of the present invention is to provide a method for controlling the turning-on of a switching tube in an electromagnetic heating system.
In order to achieve the above object, an embodiment of the present invention provides an apparatus for controlling turn-on of a switching tube in an electromagnetic heating system, where the electromagnetic heating system includes a resonant circuit including a heating coil, a resonant capacitor, and the switching tube, and a power supply circuit for supplying power to the resonant circuit, and the apparatus includes: a first voltage dividing circuit for dividing a supply voltage output by the supply circuit to output a first voltage; the second voltage division circuit is used for dividing the collector voltage of the switching tube to output a second voltage; a comparison circuit for comparing the first voltage and the second voltage to output a comparison signal; and the driving controller acquires the oscillation half cycle and the collector voltage reference point of the resonant circuit according to the comparison signal, calculates the delay time according to the oscillation half cycle of the resonant circuit, and controls the switching tube to delay the opening of the delay time when the collector voltage of the switching tube oscillates to the collector voltage reference point.
According to the switching-on control device of the switching tube in the electromagnetic heating system provided by the embodiment of the invention, the driving controller acquires the oscillation half period and the collector voltage reference point of the resonance circuit through the comparison signal output by the comparator, calculates the delay time according to the oscillation half period of the resonance circuit, and controls the switching tube to switch on after delaying the delay time when the collector voltage of the switching tube oscillates to the collector voltage reference point, so that the switching tube can be controlled to switch on at the lowest point of the collector voltage, the leading voltage can be reduced, the electromagnetic heating energy efficiency can be improved, the power resource can be saved, and the service life of a product can be prolonged.
According to some embodiments of the present invention, the driving controller includes a timing unit and a control unit, wherein the control unit controls the timing unit to start timing when the comparison signal is inverted for a first time, and controls the timing unit to stop timing when the comparison signal is inverted for a second time, to take a timing time as an oscillation half period of the resonance circuit, and to take the timing time as the collector voltage reference point when the inversion for the second time is occurred.
According to some embodiments of the invention, the drive controller calculates the delay time period at a pot detection stage before the electromagnetic heating system heats, or the drive controller calculates the delay time period at least once during the electromagnetic heating system heats.
According to some embodiments of the invention, the drive controller calculates the delay time period according to the following formula:
T ds ＝K×T CD
wherein, T ds For the delay time, K is a predetermined coefficient, T CD Is the oscillation half-cycle of the resonant circuit.
According to some embodiments of the invention, the comparison circuit comprises: and the positive input end of the comparator is connected with the first voltage division circuit, the negative input end of the comparator is connected with the second voltage division circuit, and the output end of the comparator is connected with the driving controller.
According to some embodiments of the present invention, the first voltage dividing circuit includes a first resistor and a second resistor, one end of the first resistor is connected to the power supply circuit, the other end of the first resistor is connected to one end of the second resistor, the other end of the second resistor is grounded, and a first node is located between the first resistor and the second resistor, wherein the first node is connected to the positive input terminal of the comparator; the second voltage division circuit comprises a third resistor and a fourth resistor, one end of the third resistor is connected with a collector of the switching tube, the other end of the third resistor is connected with one end of the fourth resistor, the other end of the fourth resistor is grounded, a second node is arranged between the third resistor and the fourth resistor, and the second node is connected with a negative input end of the comparator.
In order to achieve the above object, in another aspect, the present invention provides an electromagnetic heating system, which includes an on control device for a switch tube in the electromagnetic heating system.
According to the electromagnetic heating system provided by the embodiment of the invention, the switching-on control device of the switching tube can control the switching-on of the switching tube at the lowest point of the collector voltage, so that the leading voltage can be reduced, the electromagnetic heating energy efficiency can be improved, the power resource can be saved, and the service life of a product can be prolonged.
In order to achieve the above object, a further embodiment of the present invention provides a method for controlling turn-on of a switching tube in an electromagnetic heating system, where the electromagnetic heating system includes a resonant circuit composed of a heating coil, a resonant capacitor and a switching tube, and a power supply circuit for supplying power to the resonant circuit, and the method includes the following steps: dividing a power supply voltage output by the power supply circuit to output a first voltage; dividing the collector voltage of the switching tube to output a second voltage; comparing the first voltage and the second voltage to output a comparison signal; and acquiring an oscillation half cycle and a collector voltage reference point of the resonance circuit according to the comparison signal, calculating a delay time according to the oscillation half cycle of the resonance circuit, and controlling the switching tube to delay the opening of the delay time when the collector voltage of the switching tube oscillates to the collector voltage reference point.
According to the switching tube switching-on control method in the electromagnetic heating system provided by the embodiment of the invention, the oscillation half period and the collector voltage reference point of the resonance circuit are obtained through the comparison signal output by the comparator, the delay time length is calculated according to the oscillation half period of the resonance circuit, and the switching tube is controlled to be switched on after the delay time length is carried out when the collector voltage of the switching tube oscillates to the collector voltage reference point, so that the switching tube can be controlled to be switched on at the lowest point of the collector voltage, the leading voltage can be reduced, the electromagnetic heating energy efficiency can be improved, the power resource can be saved, and the service life of a product can be prolonged.
According to some embodiments of the invention, timing according to the comparison signal specifically comprises: and controlling a timing unit to start timing when the comparison signal is turned for the first time, and controlling the timing unit to stop timing when the comparison signal is turned for the second time, so that the timing time is used as the oscillation half period of the resonant circuit, and the timing time when the second turning occurs is used as the reference point of the collector voltage.
According to some embodiments of the present invention, the method for controlling the turning on of the switching tube in the electromagnetic heating system further comprises: calculating the time delay duration in a pot detection stage before the electromagnetic heating system heats, or calculating the time delay duration at least once in the heating period of the electromagnetic heating system.
According to some embodiments of the invention, the delay time duration may be calculated according to the following formula:
T ds ＝K×T CD
wherein, T ds For the delay time, K is a predetermined coefficient, T CD Is the oscillation half-cycle of the resonant circuit.
Drawings
Fig. 1 is a block schematic diagram of a switching control device of a switching tube in an electromagnetic heating system according to an embodiment of the present invention;
fig. 2 is a block diagram schematically illustrating an on control device of a switching tube in an electromagnetic heating system according to an embodiment of the present invention;
fig. 3 is an operation principle diagram of an on control device of a switching tube in an electromagnetic heating system according to an embodiment of the present invention;
fig. 4 is a schematic circuit diagram of a switching control device of a switching tube in an electromagnetic heating system according to an embodiment of the present invention;
fig. 5 is a flowchart of a method for controlling the turning on of a switching tube in an electromagnetic heating system according to an embodiment of the present invention.
Reference numerals are as follows:
the circuit comprises a resonance circuit 10, a heating coil L1, a resonance capacitor C1, a switching tube Q1 and a power supply circuit 20;
a turn-on control device 30, a first voltage dividing circuit 301, a second voltage dividing circuit 302, a comparison circuit 303, and a drive controller 304;
a timing unit 41 and a control unit 42;
comparator LM1, first resistance R1, second resistance R2, third resistance R3 and fourth resistance R3.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
An electromagnetic heating system, and an apparatus and a method for controlling the turn-on of a switching tube in the electromagnetic heating system according to embodiments of the present invention will be described with reference to the accompanying drawings.
Fig. 1 is a block diagram of a switching control device for a switching tube in an electromagnetic heating system according to an embodiment of the present invention, the switching control device is mainly suitable for the switching tube working under the leading condition. As shown in fig. 1, the electromagnetic heating system includes a resonant circuit 10 and a power supply circuit 20.
As shown in fig. 1, the heating coil L1 and the resonant capacitor C1 may be connected in parallel, one end of the heating coil L1 and one end of the resonant capacitor C1 after being connected in parallel are connected to the power supply circuit 20, the other end of the heating coil L1 and the other end of the resonant capacitor C1 after being connected in parallel are connected to one end of the switching tube Q1, the other end of the switching tube Q1 is grounded, and the control end of the switching tube Q1 is connected to the switching-on control device. Of course, it is understood that the heating coil L1 and the resonance capacitor C1 may also be connected in series.
The resonant circuit 10 consists of a heating coil L1, a resonant capacitor C1 and a switching tube Q1, and the resonant circuit 10 is used for carrying out resonant heating on the cookware; the supply circuit 20 may comprise a rectifier, the supply circuit 20 being adapted to supply the resonant circuit 10. Specifically, when the switching tube Q1 is turned on, the heating coil L1 is charged in preparation for maintaining the oscillation between the heating coil L1 and the resonance capacitor C1, and when the switching tube Q1 is turned off, the heating coil L1 and the resonance capacitor C1 oscillate. Therefore, an alternating magnetic field is generated around the heating coil L1, most of magnetic lines of force of the alternating magnetic field pass through the cookware, and a large amount of eddy current is generated in the bottom of the cookware, so that heat required by cooking is generated.
In addition, the supply circuit 20 may also comprise a filter, which is connected between the rectifier and the resonant circuit 10.
It should be noted that, one on and one off of the switch Q1 can be used as a heating cycle.
As shown in fig. 1, activation control device 30 includes: a first voltage-dividing circuit 301, a second voltage-dividing circuit 302, a comparing circuit 303, and a drive controller 304.
The first voltage dividing circuit 301 is configured to divide a power supply voltage output by the power supply circuit 20 to output a first voltage; the second voltage dividing circuit 302 is configured to divide the collector voltage of the switching tube Q1 to output a second voltage; the comparison circuit 303 is configured to compare the first voltage and the second voltage to output a comparison signal. That is, the first voltage divider 301 may divide the voltage at the input terminal of the resonant circuit 10 to output the first voltage through the output terminal of the first voltage divider 301, the second voltage divider 302 may divide the voltage at the output terminal of the resonant circuit 10 to output the second voltage through the output terminal of the second voltage divider 302, and the first voltage and the second voltage are compared by the comparator 303 to generate the comparison signal. In other words, the comparison circuit 303 may compare the voltages across the resonance circuit 10, i.e., the heating coil L1.
The driving controller 304 is connected to the control end of the switching tube, and the driving controller 304 acquires the oscillation half cycle and the collector voltage reference point of the resonant circuit 10 according to the comparison signal, calculates the delay time according to the oscillation half cycle of the resonant circuit 10, and controls the switching tube Q1 to delay the turn-on of the delay time when the collector voltage of the switching tube oscillates to the collector voltage reference point.
That is, the comparison circuit 303 compares the first voltage and the second voltage to output a comparison signal to the drive controller 304, the drive controller 304 may first obtain an oscillation half-cycle of the resonant circuit 10 according to the comparison signal, and calculate a delay time from the collector voltage reference point to the lowest point of the collector voltage according to the oscillation half-cycle of the resonant circuit 10, and the drive controller 304 further detects the collector voltage reference point according to the comparison signal, and when the collector voltage reference point is detected, the drive controller 304 controls the switching tube to be turned on after delaying the delay time, so that the switching tube is turned on when the collector voltage oscillates to the lowest point.
Therefore, the switching-on control device of the switching tube in the electromagnetic heating system provided by the embodiment of the invention can control the switching-on of the switching tube at the lowest point of the collector voltage, can reduce the leading voltage, improve the electromagnetic heating energy efficiency, save the power resource and prolong the service life of a product.
According to an embodiment of the present invention, the driving controller 304 may calculate the delay time period according to the following formula:
T ds ＝K×T CD
wherein, T ds For the delay time, K is a predetermined coefficient, T CD Is the oscillation half-cycle of the resonant circuit.
According to a specific example of the present invention, the main Control Unit 104 may be an MCU (Micro Control Unit), and the switch tube may be an IGBT tube or an MOS tube.
Specifically, according to an embodiment of the present invention, as shown in fig. 2, the driving controller 304 includes a timing unit 41 and a control unit 42, wherein the control unit 43 controls the timing unit 41 to start timing when the comparison signal is inverted for the first time, and the control unit 42 controls the timing unit 41 to stop timing when the comparison signal is inverted for the second time, so as to take the timing time as the oscillation half period of the resonant circuit 10 and take the timing time as the collector voltage reference point when the inversion for the second time occurs.
That is, in each heating cycle of the resonant circuit 10, when it is firstWhen the voltage and the second voltage trigger the comparison circuit 303 to flip over at the rising edge (falling edge), that is, to flip over for the first time, the timing unit 41 in the driving controller 304 starts timing, and as the oscillation progresses, the collector voltage of the switching tube changes substantially according to a sinusoidal rule, and when the first voltage and the second voltage trigger the comparison circuit 303 to flip over at the falling edge (rising edge), that is, to flip over for the second time, the timing unit 41 in the driving controller 304 ends timing. The timing time of the timing unit 41 can be regarded as the oscillation half period of the resonant circuit 10, and the driving controller 304 can pass the preset relationship T according to the oscillation half period of the resonant circuit 10 ds ＝K×T CD And calculating the time delay duration. In addition, in the heating process, when the driving controller 304 determines that the comparison circuit 303 turns over for the second time, the delay time duration is equal to control the switching tube Q1 to be turned on so that the collector voltage of the switching tube oscillates to the lowest point.
Specifically, when the driving controller 304 controls the switching tube Q1 to be turned off, the switching tube Q1 is turned on, and the collector voltage of the switching tube Q1 is close to 0V. When the driving controller 304 controls the switching tube Q1 to turn off, the current of the heating coil L1 flows in a forward direction and charges the resonant capacitor C1, the collector voltage of the switching tube Q1, i.e. the second voltage Vout2, rises, wherein the first voltage Vout1 remains substantially unchanged, the waveforms of the first voltage Vout1 and the second voltage Vout2 change as shown in fig. 3, when the second voltage Vout2 exceeds the first voltage Vout1, the collector voltage of the switching tube is as shown by point C in fig. 3, the comparison signal of the comparison circuit 303 changes from the first level to the second level, the driving controller 304 determines that the comparison signal flips for the first time, and the timing unit 41 starts timing.
Then, when the energy release of the heating coil L1 is completed, the collector voltage of the switching tube reaches the maximum value as shown by a point a in fig. 3, after the collector voltage of the switching tube reaches the maximum value, the resonant capacitor C1 is switched to discharge to the heating coil L1, the current on the heating coil L1 flows in the reverse direction until the electric energy release of the resonant capacitor C1 is completed, and the current on the heating coil L1 continues to flow in the reverse direction due to the inductance effect because the reverse current also flows in the heating coil L1, and at this stage, the collector voltage of the switching tube does not flow in the reverse directionWhen the collector voltage of the switching tube drops below the first voltage Vout1, the collector voltage of the switching tube changes from the second level to the first level as shown by point D in fig. 3, the comparison signal of the comparison circuit 303 changes from the second level to the first level, the driving controller 304 determines that the comparison signal is inverted for the second time, and the timing unit 41 ends timing. The controller 304 may thus acquire the oscillation half period T of the resonant circuit 10 CD And according to T CD The oscillation half period of the resonant circuit 10 is calculated by the preset relationship to obtain the delay time T ds ＝K×T CD 。
In addition, in the heating process, when the driving controller 304 determines that the comparison circuit 303 turns over for the second time, that is, the collector voltage reaches the point D, the driving controller 304 delays the delay time period T each time ds Then, the switching tube Q1 is controlled to be turned on, i.e. the collector voltage reaches point E in fig. 3.
According to some embodiments of the invention, the drive controller 304 may calculate the delay period during a pot check phase before the electromagnetic heating system heats up, or the drive controller 304 may calculate the delay period at least once during the heating of the electromagnetic heating system.
It should be noted that the delay time is different according to different loads, for example, the delay time corresponding to different pots is different.
The corresponding delay time of each cooker is assumed to be fixed, and the delay time does not change with the voltage in the mains supply envelope. Before each heating, the oscillation half period of the resonant circuit 10 can be determined by detecting the pan, and the delay time length can be calculated, so that the delay time length can be obtained. Particularly, under the condition of having placed the pan on electromagnetic heating system, drive controller 304 controls electromagnetic heating system earlier and gets into and examines the pot stage to examine pot stage and obtain resonant circuit 10's oscillation half cycle according to comparison signal, and through predetermineeing relation T ds ＝K×T CD The delay time is obtained. Then, the driving controller 304 controls the electromagnetic heating system to enter a heating stage, determines a collector voltage reference point according to the comparison signal, and controls the switching tube Q1 to be turned on for a delay time when the comparison signal is judged to be turned over for the second time when the collector voltage reference point is detected each timeThe method is simple.
Further, it is assumed that the delay time remains varying with voltage within the mains envelope. During normal heating of the electromagnetic heating system, the driving controller 304 continuously obtains the oscillation half period of the resonant circuit 10, for example, the driving controller 304 may detect the oscillation half period of the resonant circuit 10 once every heating period, so as to pass T through every heating period ds ＝K×T CD And calculating the time delay duration required by the current heating period, and controlling the switching tube Q1 to switch on the time delay duration when the comparison signal is judged to turn over for the second time when the reference point of the collector voltage is detected, so that the real-time performance and the accuracy of the time delay duration are maintained.
It should be understood that the delay period may be calculated every predetermined heating period, but it is ensured that the delay period is calculated at least once for each heating.
The circuit principle of the turn-on control device according to the embodiment of the present invention is described in detail below with reference to fig. 4.
As shown in fig. 4, the comparison circuit 303 includes: a comparator LM1. The positive input end of the comparator LM1 is connected to the first voltage-dividing circuit 301, the negative input end of the comparator LM1 is connected to the second voltage-dividing circuit 302, and the output end of the comparator LM1 is connected to the driving controller 304.
As shown in fig. 4, the first voltage divider circuit 301 includes a first resistor R1 and a second resistor R2, one end of the first resistor R1 is connected to the power supply circuit 20, that is, to the input terminal of the resonant circuit 10, the other end of the first resistor R1 is connected to one end of the second resistor R2, the other end of the second resistor R2 is grounded, and a first node is provided between the first resistor R1 and the second resistor R2, where the first node is connected to the positive input terminal of the comparator LM 1; the second voltage-dividing circuit 302 includes a third resistor R3 and a fourth resistor R3, one end of the third resistor R3 is connected to the collector of the switching tube Q1, i.e., connected to the output terminal of the resonant circuit 10, the other end of the third resistor R3 is connected to one end of the fourth resistor R4, the other end of the fourth resistor R4 is grounded, a second node is provided between the third resistor R3 and the fourth resistor R4, and the second node is connected to the negative input terminal of the comparator LM1.
That is, when the second voltage Vout2 exceeds the first voltage Vout1, the comparator LM1 outputs a low level, that is, the comparator LM1 generates a falling edge, the driving controller 304 determines that the comparison signal is inverted for the first time, and the timing unit 41 starts timing. Then, when the second voltage Vout2 is lower than the first voltage Vout1, the comparator LM1 outputs a high level, that is, the comparator LM1 generates a rising edge, the driving controller 304 determines that the comparison signal is inverted for the second time, and the timing unit 41 ends timing.
It should be understood that the positive input of the comparator LM1 may also be connected to the second voltage-dividing circuit 302, and correspondingly, the negative input of the comparator LM1 is connected to the first voltage-dividing circuit 301. At this time, when the second voltage Vout2 exceeds the first voltage Vout1, the comparator LM1 outputs a high level, that is, the comparator LM1 generates a rising edge, the driving controller 304 determines that the comparison signal is inverted for the first time, and the timing unit 41 starts timing. Then, when the second voltage Vout2 is lower than the first voltage Vout1, the comparator LM1 outputs a low level, that is, the comparator LM1 generates a falling edge, the driving controller 304 determines that the comparison signal is inverted for the second time, and the timing unit 41 ends timing.
In summary, according to the switching control device of the switching tube in the electromagnetic heating system provided by the embodiment of the invention, the driving controller obtains the oscillation half cycle and the collector voltage reference point of the resonant circuit through the comparison signal output by the comparator, calculates the delay time according to the oscillation half cycle of the resonant circuit, and controls the switching tube to switch on the delay time when the collector voltage of the switching tube oscillates to the collector voltage reference point, so that the switching tube can be controlled to switch on the lowest point of the collector voltage, the leading voltage can be reduced, the electromagnetic heating energy efficiency can be improved, the power resource can be saved, and the service life of the product can be prolonged.
In another aspect, an embodiment of the present invention further provides an electromagnetic heating system, where the electromagnetic heating system includes a switching-on control device for a switching tube in the electromagnetic heating system.
According to the electromagnetic heating system provided by the embodiment of the invention, the switching-on control device of the switching tube can control the switching-on of the switching tube at the lowest point of the collector voltage, so that the advance voltage can be reduced, the electromagnetic heating energy efficiency can be improved, the power resource can be saved, and the service life of a product can be prolonged.
In order to achieve the above object, another embodiment of the present invention provides a method for controlling the turn-on of a switching tube in an electromagnetic heating system.
Fig. 5 is a flowchart of a method for controlling the turning on of a switching tube in an electromagnetic heating system according to an embodiment of the present invention. The electromagnetic heating system comprises a resonance circuit consisting of a heating coil, a resonance capacitor and a switching tube, and a power supply circuit for supplying power to the resonance circuit. It should be understood that the specific structure and operation principle of the electromagnetic heating system have been described in the above embodiments, and are not described in detail here for the sake of brevity.
As shown in fig. 5, the method for controlling the on-state of the switching tube in the electromagnetic heating system includes the following steps:
s1: the power supply circuit divides a power supply voltage output by the power supply circuit to output a first voltage.
S2: and dividing the collector voltage of the switching tube to output a second voltage.
S3: the first voltage and the second voltage are compared to output a comparison signal.
That is, the voltage at the input terminal of the resonant circuit may be divided to output a first voltage, and the voltage at the output terminal of the resonant circuit may be divided to output a second voltage, and the first voltage and the second voltage may be compared to generate the comparison signal. In other words, the voltages across the resonant circuit, i.e. the heating coil, can be compared.
S4: and obtaining the oscillation half cycle and the collector voltage reference point of the resonance circuit according to the comparison signal, calculating the delay time according to the oscillation half cycle of the resonance circuit, and controlling the switching tube to delay the opening of the delay time when the collector voltage of the switching tube oscillates to the collector voltage reference point.
That is to say, the oscillation half cycle of the resonant circuit can be obtained according to the comparison signal, the time delay time from the collector voltage reference point to the lowest point of the collector voltage can be calculated according to the oscillation half cycle of the resonant circuit, the collector voltage reference point can be detected according to the comparison signal, and when the collector voltage reference point is detected, the switching tube is controlled to be switched on after the time delay time is long, so that the switching tube is switched on when the collector voltage oscillates to the lowest point.
Therefore, the switching-on control method for the switching tube in the electromagnetic heating system provided by the embodiment of the invention can control the switching-on of the switching tube at the lowest point of the collector voltage, can reduce the leading voltage, can improve the electromagnetic heating energy efficiency, can save power resources and can prolong the service life of a product.
According to an embodiment of the present invention, the delay time duration may be calculated according to the following formula:
T ds ＝K×T CD
wherein, T ds For the delay time, K is a predetermined coefficient, T CD Is the oscillation half-cycle of the resonant circuit.
Specifically, according to an embodiment of the present invention, the timing according to the comparison signal specifically includes: the timing unit is controlled to start timing when the comparison signal is inverted for the first time, and to stop timing when the comparison signal is inverted for the second time, so that the timing time is used as an oscillation half period of the resonance circuit, and the timing time when the inversion for the second time is generated is used as a reference point of the collector voltage.
That is, in each heating cycle of the resonant circuit, when the first voltage and the second voltage trigger the comparator circuit to generate the rising edge (falling edge) inversion, namely the first inversion, the timing is started, along with the oscillation, the collector voltage of the switch tube basically changes according to the sine rule, and when the first voltage and the second voltage trigger the comparator circuit to generate the falling edge (rising edge) inversion, namely the second inversion, the timing is ended. The timing time can be regarded as the oscillation half period of the resonant circuit, and can be determined according to the oscillation half period of the resonant circuit and through the preset relation T ds ＝K×T CD And calculating the time delay duration. In addition, in the heating process, when the comparison signal is judged to turn over for the second time, the time delay time is delayed for controlling the switching tube to be switched on so as to enable the voltage of the collector electrode of the switching tube to oscillate to the lowest point.
According to some embodiments of the present invention, the method for controlling the opening of the switching tube in the electromagnetic heating system further comprises: and calculating the time delay duration in a pot detection stage before the electromagnetic heating system heats, or calculating the time delay duration at least once during the heating of the electromagnetic heating system.
It should be noted that the delay time is different according to different loads, for example, the delay time corresponding to different pots is different.
The corresponding delay time of each cooker is assumed to be fixed, and the delay time does not change with the voltage in the mains supply envelope. Before each heating, the oscillation half period of the resonant circuit can be determined by detecting the pan, and the delay time length is further calculated, so that the delay time length is obtained. Particularly, under the condition of having placed the pan on electromagnetic heating system, control electromagnetic heating system earlier and get into and examine a pot stage to examine a pot stage and acquire resonant circuit's oscillation half cycle according to comparison signal, and through predetermineeing relation T ds ＝K×T CD The delay time is obtained. And then, controlling the electromagnetic heating system to enter a heating stage, determining a collector voltage reference point according to the comparison signal, and controlling the switching tube Q1 to be switched on in a delay time when judging that the comparison signal turns over for the second time when detecting the collector voltage reference point each time.
Further, it is assumed that the delay time duration remains varying with different voltages within the mains envelope. During normal heating of the electromagnetic heating system, the oscillation half-period of the resonant circuit is continuously obtained, for example, the oscillation half-period of the resonant circuit can be detected once per heating period, so that T passes through each heating period ds ＝K×T CD And calculating the time delay duration required by the current heating period, and controlling the switching tube to switch on the time delay duration when the comparison signal is judged to turn over for the second time when the reference point of the collector voltage is detected, so that the real-time performance and the accuracy of the time delay duration are maintained.
It should be understood that the delay period may be calculated every predetermined heating period, but it is ensured that the delay period is calculated at least once for each heating.
In summary, according to the switching-on control method for the switching tube in the electromagnetic heating system provided by the embodiment of the present invention, the oscillation half cycle of the resonant circuit and the collector voltage reference point are obtained through the comparison signal output by the comparator, the delay time is calculated according to the oscillation half cycle of the resonant circuit, and the switching tube is controlled to switch on after delaying the delay time when the collector voltage of the switching tube oscillates to the collector voltage reference point, so that the switching tube can be controlled to switch on at the lowest point of the collector voltage, the leading voltage can be reduced, the electromagnetic heating energy efficiency can be improved, the power resource can be saved, and the service life of the product can be prolonged.
In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood according to specific situations by those of ordinary skill in the art.
In the present invention, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the second feature or the first and second features may be indirectly contacting each other through intervening media. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean 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 invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer 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, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (11)
1. The switching-on control device of the switching tube in the electromagnetic heating system is characterized in that the electromagnetic heating system comprises a resonance circuit consisting of a heating coil, a resonance capacitor and the switching tube and a power supply circuit for supplying power to the resonance circuit, wherein the power supply circuit comprises a rectifier and a filter, and the filter is connected between the rectifier and the resonance circuit;
the turn-on control device includes:
a first voltage dividing circuit for dividing a supply voltage output by the supply circuit to output a first voltage;
the second voltage division circuit is used for dividing the collector voltage of the switching tube to output a second voltage;
a comparison circuit for comparing the first voltage and the second voltage to output a comparison signal;
and the driving controller acquires the oscillation half cycle and the collector voltage reference point of the resonant circuit according to the comparison signal, calculates the delay time according to the oscillation half cycle of the resonant circuit, and controls the switching tube to delay the opening of the delay time when the collector voltage of the switching tube oscillates to the collector voltage reference point.
2. The turn-on control device of switching tube in electromagnetic heating system according to claim 1, wherein the driving controller includes a timing unit and a control unit, wherein,
the control unit controls the timing unit to start timing when the comparison signal is turned for the first time, and controls the timing unit to stop timing when the comparison signal is turned for the second time, so that the timing time is used as the oscillation half period of the resonant circuit, and the timing time when the comparison signal is turned for the second time is used as the reference point of the collector voltage.
3. The device for controlling the on-state of the switching tube in the electromagnetic heating system according to claim 1, wherein the driving controller calculates the delay time period in a pot inspection stage before the electromagnetic heating system heats, or the driving controller calculates the delay time period at least once during the heating of the electromagnetic heating system.
4. The apparatus for controlling the turn-on of a switching tube in an electromagnetic heating system according to claim 1 or 3, wherein the driving controller calculates the delay time period according to the following formula:
T ds ＝K×T CD
wherein, T ds For the delay time, K is a predetermined coefficient, T CD Is the oscillation half-cycle of the resonant circuit.
5. The apparatus for controlling the turn-on of a switching tube in an electromagnetic heating system according to claim 1, wherein the comparison circuit comprises:
and the positive input end of the comparator is connected with the first voltage division circuit, the negative input end of the comparator is connected with the second voltage division circuit, and the output end of the comparator is connected with the driving controller.
6. The apparatus for controlling the opening of a switching tube in an electromagnetic heating system according to claim 5,
the first voltage division circuit comprises a first resistor and a second resistor, one end of the first resistor is connected with the power supply circuit, the other end of the first resistor is connected with one end of the second resistor, the other end of the second resistor is grounded, a first node is arranged between the first resistor and the second resistor, and the first node is connected with the positive input end of the comparator;
the second voltage division circuit comprises a third resistor and a fourth resistor, one end of the third resistor is connected with a collector of the switching tube, the other end of the third resistor is connected with one end of the fourth resistor, the other end of the fourth resistor is grounded, a second node is arranged between the third resistor and the fourth resistor, and the second node is connected with a negative input end of the comparator.
7. An electromagnetic heating system, characterized by comprising a switching tube on control device according to any one of claims 1-6.
8. A switching-on control method of a switching tube in an electromagnetic heating system is characterized in that the electromagnetic heating system comprises a resonance circuit consisting of a heating coil, a resonance capacitor and the switching tube and a power supply circuit for supplying power to the resonance circuit, and the switching-on control method comprises the following steps:
dividing a power supply voltage output by the power supply circuit to output a first voltage;
dividing the collector voltage of the switching tube to output a second voltage;
comparing the first voltage and the second voltage to output a comparison signal;
and acquiring an oscillation half cycle and a collector voltage reference point of the resonant circuit according to the comparison signal, calculating a delay time according to the oscillation half cycle of the resonant circuit, and controlling the switching tube to delay the opening of the delay time when the collector voltage of the switching tube oscillates to the collector voltage reference point.
9. The method for controlling the switching on of the switching tube in the electromagnetic heating system according to claim 8, wherein the timing according to the comparison signal specifically comprises:
and controlling a timing unit to start timing when the comparison signal is turned for the first time, and controlling the timing unit to stop timing when the comparison signal is turned for the second time, so that the timing time is used as the oscillation half period of the resonant circuit, and the timing time when the comparison signal is turned for the second time is used as the reference point of the collector voltage.
10. The method for controlling the turn-on of the switching tube in the electromagnetic heating system according to claim 8, further comprising: calculating the time delay duration in a pot detection stage before the electromagnetic heating system heats, or calculating the time delay duration at least once in the heating period of the electromagnetic heating system.
11. The method for controlling turning on of a switching tube in an electromagnetic heating system according to claim 8 or 10, wherein the delay time period is calculated according to the following formula:
T ds ＝K×T CD
wherein, T ds For the delay time, K is a predetermined coefficient, T CD Is the oscillation half-cycle of the resonant circuit.
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| CN201510504038.7A CN106470506B (en) | 2015-08-17 | 2015-08-17 | Electromagnetic heating system and switching-on control device and method of switch tube thereof |
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| CN1104750A (en) * | 1993-06-15 | 1995-07-05 | 三星电子株式会社 | Induction heating cooker |
| CN204013267U (en) * | 2014-06-23 | 2014-12-10 | 厦门翰普电子有限公司 | A kind of control circuit of thermatron |
| CN204442725U (en) * | 2015-03-04 | 2015-07-01 | 佛山市顺德区美的电热电器制造有限公司 | The zero passage of electromagnetic heating system and breaker in middle pipe thereof opens checkout gear |
| CN204539516U (en) * | 2015-04-29 | 2015-08-05 | 佛山市顺德区美的电热电器制造有限公司 | The zero passage of electromagnetic heating system and switching tube thereof opens control device |
| CN204906749U (en) * | 2015-08-17 | 2015-12-23 | 佛山市顺德区美的电热电器制造有限公司 | Electromagnetic heating system and switch tube open controlling means thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1104750A (en) * | 1993-06-15 | 1995-07-05 | 三星电子株式会社 | Induction heating cooker |
| CN204013267U (en) * | 2014-06-23 | 2014-12-10 | 厦门翰普电子有限公司 | A kind of control circuit of thermatron |
| CN204442725U (en) * | 2015-03-04 | 2015-07-01 | 佛山市顺德区美的电热电器制造有限公司 | The zero passage of electromagnetic heating system and breaker in middle pipe thereof opens checkout gear |
| CN204539516U (en) * | 2015-04-29 | 2015-08-05 | 佛山市顺德区美的电热电器制造有限公司 | The zero passage of electromagnetic heating system and switching tube thereof opens control device |
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