Low-power continuously adjustable heating control circuit, method and heating device

Abstract

The present invention relates to a low-power continuously adjustable heating control circuit, method and heating device, comprising: an input circuit, a zero-crossing detection circuit, a heating circuit, a driving circuit and a control unit; the input circuit performs rectification and filtering processing on an AC signal inputted from an AC input terminal, and outputs a rectified signal to a heating circuit; the zero-crossing detection circuit detects the AC signal inputted from the AC input terminal, and outputs a zero-crossing detection signal to the control unit when a zero-crossing signal is detected; the control unit drives and controls the driving circuit in accordance with the current low-continuous heating control mode in combination with the zero-crossing detection signal, so as to control the driving circuit to output a corresponding driving signal to the heating circuit, so that the heating circuit performs low-power heating according to the driving signal and the rectified signal. The present invention utilizes the zero-crossing detection signal to perform low-power heating control, which can reduce the average value of power, reduce ripple, avoid frequent sudden changes in power, and has a simple circuit structure, small size and low cost.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical appliances, and more particularly to a low-power continuously adjustable heating control circuit, method and heating device. Background Art

[0002] The single-tube topology in the traditional electromagnetic heating control board, the system works in a resonant state, the resonant frequency is determined by the coil and the resonant capacitor, and the maximum power point is generally set at the optimal resonant working point. The IGBT conduction is at the zero point of the voltage, which is conducive to low system heat generation. However, when the system is to work at low power, the IGBT conduction is at a certain voltage value. At this time, a large switching loss is generated, the IGBT generates a lot of heat, and the lower the power, the higher the step voltage, the greater the IGBT heat, resulting in low system efficiency and even over-temperature failure of the device. Usually, the maximum power controlled by the minimum continuous power value of a single tube is above 40%. Taking 2100W as an example, the minimum continuous power is 840W. If you need to achieve slow fire stewing, you can only adopt intermittent heating, such as working for 2 seconds and stopping for 2 seconds. This will cause frequent power mutations and affect the user experience.

[0003] The half-bridge topology of the traditional electromagnetic heating plate can adjust the power of the system by controlling the duty cycle and pulse drive frequency, and can achieve continuously adjustable low heating power. However, the circuit of the half-bridge topology is complex, consisting of two resonant capacitors and two IGBT tube controls. The base voltages of the IGBT tubes are different, so insulation and heat dissipation are also required, resulting in a large system size and high cost. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a low-power continuously adjustable heating control circuit, method and heating device in view of the above-mentioned defects of the prior art.

[0005] The technical solution adopted by the present invention to solve the technical problem is: constructing a low-power continuously adjustable heating control circuit, including: an input circuit, a zero-crossing detection circuit, a heating circuit, a driving circuit and a control unit;

[0006] The input end of the input circuit is connected to the AC input end, the output end of the input circuit is connected to the input end of the heating circuit, the control end of the heating circuit is connected to the output end of the drive circuit, the input end of the drive circuit is connected to the drive control end of the control unit, the detection end of the zero-crossing detection circuit is connected to the AC input end, and the output end of the zero-crossing detection circuit is connected to the zero-crossing detection end of the control unit;

[0007] The input circuit is used to perform rectification and filtering processing on the AC signal input from the AC input terminal, and output the rectified signal to the heating circuit;

[0008] The zero-crossing detection circuit is used to detect the AC signal input from the AC input terminal, and output a zero-crossing detection signal to the control unit when a zero-crossing signal is detected;

[0009] The control unit is used to drive and control the drive circuit according to the current low continuous heating control mode in combination with the zero-crossing detection signal, so as to control the drive circuit to output a corresponding drive signal to the heating circuit, so that the heating circuit performs low-power heating according to the drive signal and the rectifier signal.

[0010] In the low-power continuously adjustable heating control circuit of the present invention, the input circuit includes: an EMC filter circuit and a rectifier filter circuit;

[0011] The input end of the EMC filter circuit is connected to the AC input end, the output end of the EMC filter circuit is connected to the input end of the rectifier filter circuit, and the output end of the rectifier filter circuit is connected to the input end of the heating circuit.

[0012] The low-power continuously adjustable heating control circuit of the present invention further includes: a thyristor control circuit;

[0013] The thyristor control circuit is connected to the input circuit and the control unit respectively;

[0014] The thyristor control circuit is used to be turned on or off according to the control of the control unit to control the connection or disconnection between the input circuit and the heating circuit.

[0015] The low-power continuously adjustable heating control circuit of the present invention further includes: a current detection circuit;

[0016] The circuits are respectively connected to the rectifying and filtering circuit and the control unit, and are used for current detection and outputting current detection signals to the control unit.

[0017] The low-power continuously adjustable heating control circuit of the present invention further includes: a voltage detection circuit connected to the EMC filter circuit and the control unit respectively;

[0018] The voltage detection circuit is used to detect the input voltage and output a voltage detection signal to the control unit.

[0019] The low-power continuously adjustable heating control circuit of the present invention further includes: a resonant circuit connected to the heating circuit and the control unit respectively;

[0020] The resonant circuit is used to perform resonance processing on the heating signal of the heating circuit and output the resonance signal to the control unit.

[0021] The low-power continuously adjustable heating control circuit of the present invention further includes: a power supply circuit connected to the EMC filter circuit;

[0022] The power supply circuit is used to convert the input voltage and output a power supply signal.

[0023] In the low-power continuously adjustable heating control circuit of the present invention, the EMC filter circuit includes: a varistor, a first capacitor, an eighth resistor, a tenth resistor, a common-mode inductor, a ninth resistor, an eleventh resistor, a second capacitor, a seventh capacitor and a sixth capacitor;

[0024] The first end of the varistor is connected to the live wire of the AC input end, the second end of the varistor is connected to the neutral wire of the AC input end, the first capacitor is connected to the varistor in parallel, the first end of the eighth resistor is connected to the first end of the varistor, the second end of the eighth resistor is connected to the first end of the tenth resistor, the second end of the tenth resistor is connected to the second end of the varistor, the first end of the common-mode inductor is connected to the first end of the varistor, the second end of the common-mode inductor is connected to the second end of the varistor, the third end of the common-mode inductor is connected to the first end of the ninth resistor, the first end of the second capacitor and the first end of the sixth capacitor, the second end of the common-mode inductor is connected to the second end of the eleventh resistor, the second end of the seventh capacitor and the second end of the sixth capacitor, the second end of the ninth resistor is connected to the first end of the eleventh resistor, the second end of the second capacitor is connected to the first end of the seventh capacitor, the first end of the sixth capacitor is connected to the rectifier and filter circuit through the thyristor control circuit, and the second end of the sixth capacitor is connected to the rectifier and filter circuit.

[0025] In the low-power continuously adjustable heating control circuit of the present invention, the thyristor control circuit comprises: a fourth capacitor, a seventh resistor, a thyristor, a second resistor, a third resistor, a first photocoupler, a first resistor and a first transistor;

[0026] The first end of the fourth capacitor is connected to the first end of the second resistor, the second end of the fourth capacitor is connected to the first end of the second capacitor, the second end of the seventh resistor is connected to the first end of the second capacitor, the first end of the seventh resistor is connected to the first end of the second resistor, the second end of the second resistor is connected to the sixth end of the first photoelectric coupler, the fourth end of the first photoelectric coupler is connected to the output end of the thyristor through the third resistor, the input end of the thyristor is connected to the first end of the fourth capacitor, the output end of the thyristor is also connected to the rectifier and filter circuit, and the control end of the thyristor is connected to the first end of the second resistor; the first end of the first photoelectric coupler is connected to the second power supply output end of the power supply circuit through the first resistor, the second end of the first photoelectric coupler is connected to the collector of the first transistor, the emitter of the first transistor is grounded, and the base of the first transistor is connected to the thyristor control end of the control unit.

[0027] In the low-power continuously adjustable heating control circuit of the present invention, the rectification and filtering circuit comprises: a rectifier bridge, a second inductor and an eighth capacitor;

[0028] The first input end of the rectifier bridge is connected to the output end of the thyristor, the second input end of the rectifier bridge is connected to the second end of the sixth capacitor, the positive output end of the rectifier bridge is connected to the first end of the second inductor, the second end of the second inductor is connected to the first end of the eighth capacitor and the input end of the heating circuit, the second end of the eighth capacitor is grounded, and the negative output end of the rectifier bridge is grounded through a detection resistor.

[0029] In the low-power continuously adjustable heating control circuit of the present invention, the heating circuit comprises: a heating coil, a fifth capacitor and an IGBT tube;

[0030] The first end of the heating coil is connected to the second end of the second inductor, the second end of the heating coil is connected to the first end of the IGBT tube, the fifth capacitor is connected in parallel with the heating coil, the second end of the IGBT tube is grounded, and the third end of the IGBT tube is connected to the output end of the drive circuit.

[0031] In the low-power continuously adjustable heating control circuit of the present invention, the driving circuit includes: a fourteenth resistor, a third voltage-stabilizing tube, a twelfth resistor, a second triode, a fifth triode, a fourth resistor, a fifth resistor, a third triode, a sixth resistor, a thirteenth resistor, a third capacitor and a first filter capacitor;

[0032] The first end of the twelfth resistor is connected to the third end of the IGBT tube, the second end of the twelfth resistor is connected to the emitter of the second transistor and the emitter of the fifth transistor, the first end of the fourteenth resistor is connected to the first end of the twelfth resistor, the second end of the fourteenth resistor and the anode of the third voltage regulator tube are grounded, and the cathode of the third voltage regulator tube is connected to the first end of the twelfth resistor;

[0033] The collector of the fifth transistor is grounded, the base of the fifth transistor is connected to the base of the second transistor, the collector of the third transistor and the second end of the fifth resistor, the collector of the second transistor is connected to the first power supply output end of the power supply circuit through the fourth resistor; the first end of the fifth resistor is connected to the first power supply output end of the power supply circuit, the emitter of the third transistor is grounded, the base of the third transistor is connected to the first power supply output end of the power supply circuit through the sixth resistor, the first end of the third capacitor is connected to the first power supply output end of the power supply circuit, the second end of the third capacitor is grounded, and the first filter capacitor is connected in parallel with the third capacitor; the base of the third transistor is also connected to the drive control end of the control unit through the thirteenth resistor.

[0034] In the low-power continuously adjustable heating control circuit of the present invention, the voltage detection circuit includes: a second diode, a fifth diode, a sixteenth resistor, a seventeenth resistor, a twenty-first resistor, a twenty-second resistor, a tenth capacitor, a twenty-third resistor, a twenty-fourth resistor and an eleventh capacitor;

[0035] The anode of the second diode is connected to the fourth end of the common-mode inductor, the anode of the fifth diode is connected to the third end of the common-mode inductor, and the cathode of the second diode and the cathode of the fifth diode are connected and connected to the input end of the power supply circuit;

[0036] A first end of the sixteenth resistor is connected to the cathode of the second diode and the cathode of the fifth diode, a second end of the sixteenth resistor is grounded via the twenty-first resistor and the twenty-third resistor in sequence, the tenth capacitor is connected to the twenty-third resistor in parallel, and a connection end of the sixteenth resistor and the twenty-first resistor is also connected to a first voltage detection end of the control unit;

[0037] The first end of the seventeenth resistor is connected to the cathode of the second diode and the cathode of the fifth diode, the second end of the seventeenth resistor is grounded through the twenty-second resistor and the twenty-fourth resistor in sequence, the eleventh capacitor is connected to the twenty-fourth resistor in parallel, and the connecting end of the seventeenth resistor and the twenty-second resistor is also connected to the second voltage detection terminal of the control unit.

[0038] In the low-power continuously adjustable heating control circuit described in the present invention, the power supply circuit includes: a fourth diode, a second filter capacitor, a fifteenth resistor, an eighteenth resistor, a ninth capacitor, a sixth diode, a transformer, a first power supply chip, a seventh diode, an eighth diode, a third filter capacitor, a ninth diode, a tenth voltage regulator tube, a twentieth capacitor, a fourth filter capacitor, a twenty-first capacitor, a sixth filter capacitor, a twenty-second capacitor, a second power supply chip, a seventh filter capacitor and a twenty-fourth capacitor;

[0039] The anode of the fourth diode is connected to the cathode of the second diode and the cathode of the fifth diode, the cathode of the fourth diode is grounded through the fifteenth resistor and the second filter capacitor in sequence, the first end of the eighteenth resistor is connected to the connection end of the fifteenth resistor and the second filter capacitor, the second end of the eighteenth resistor is connected to the cathode of the sixth diode, the ninth capacitor is connected in parallel with the eighteenth resistor, the anode of the sixth diode is connected to the first input end of the transformer, and the second input end of the transformer is connected to the first end of the eighteenth resistor;

[0040] The first output end of the transformer is connected to the anode of the eighth diode, the second output end of the transformer is connected to the anode of the seventh diode, and the third output end of the transformer is grounded; the negative end of the third filter capacitor is grounded, the positive end of the third filter capacitor is connected to the fourth pin of the first power supply chip, the eighth pin of the first power supply chip is connected to the anode of the sixth diode, the fourth pin of the first power supply chip is connected to the cathode of the ninth diode, the third pin of the first power supply chip is connected to the anode of the tenth voltage regulator tube and the first end of the twentieth capacitor, the second end of the twentieth capacitor is grounded, the anode of the ninth diode is connected to the cathode of the tenth voltage regulator tube, and the first pin and the second pin of the first power supply chip are short-circuited and connected to the ground;

[0041] The cathode of the eighth diode is connected to the positive end of the fourth filter capacitor, the negative end of the fourth filter capacitor is grounded, the first end of the twenty-first capacitor is connected to the positive end of the fourth filter capacitor and the anode of the ninth diode, the second end of the twenty-first capacitor is grounded, and the connection end between the first end of the twenty-first capacitor and the positive end of the fourth filter capacitor is the first power supply output end of the power supply circuit;

[0042] The cathode of the seventh diode is connected to the first pin of the second power supply chip and the positive end of the sixth filter capacitor, the negative end of the sixth filter capacitor is grounded, the twenty-second capacitor is connected in parallel with the sixth filter capacitor, the second pin of the second power supply chip is grounded, the third pin of the second power supply chip is the second power supply output end of the power supply circuit, the third pin of the second power supply chip is also grounded through the seventh filter capacitor, and the twenty-fourth capacitor is connected in parallel with the seventh filter capacitor.

[0043] In the low-power continuously adjustable heating control circuit of the present invention, the current detection circuit comprises: a thirty-first resistor, a fifteenth capacitor, a sixteenth capacitor, a seventeenth capacitor, a thirty-second resistor, a thirty-seventh resistor, an adjustable resistor and the detection resistor;

[0044] The first end of the detection resistor is connected to the negative output end of the rectifier bridge, the second end of the detection resistor is grounded, the first end of the thirty-first resistor is connected to the second end of the detection resistor, the second end of the thirty-first resistor is connected to the first end of the fifteenth resistor, the second end of the fifteenth resistor is grounded, the second end of the thirty-first resistor is also connected to the first current detection end of the control unit, the first end of the sixteenth capacitor is connected to the first end of the seventeenth capacitor and the first end of the thirty-second resistor, the second end of the sixteenth resistor and the second end of the seventeenth resistor are grounded, the second end of the thirty-second resistor is connected to the first end of the thirty-seventh resistor, the second end of the thirty-seventh resistor is grounded, and the adjustable resistor is connected in parallel with the thirty-seventh resistor.

[0045] In the low-power continuously adjustable heating control circuit of the present invention, the resonant circuit comprises: a nineteenth resistor, a twentieth resistor, a twenty-fifth resistor, a twenty-sixth resistor, a thirty-third resistor, a thirtieth resistor, a thirty-fourth resistor, a thirty-eighth resistor, a thirteenth capacitor, a twelfth capacitor and a fourteenth capacitor;

[0046] The first end of the nineteenth resistor is connected to the first end of the heating coil, the second end of the nineteenth resistor is grounded via the twenty-fifth resistor and the thirty-third resistor in sequence, and the connection end of the twenty-fifth resistor and the thirty-third resistor is connected to the control unit;

[0047] The first end of the 20th resistor is connected to the second end of the heating coil, the second end of the 20th resistor is grounded via the 26th resistor, the 34th resistor and the 38th resistor in sequence, the first end of the 30th resistor is connected to the connecting end of the 26th resistor and the 34th resistor, the second end of the 30th resistor is connected to the first end of the twelfth capacitor and the first end of the thirteenth capacitor, the second end of the thirteenth capacitor is grounded, the second end of the twelfth capacitor is grounded via the fourteenth capacitor, the second end of the 30th resistor is connected to the control unit, and the second end of the twelfth capacitor is connected to the control unit.

[0048] In the low-power continuously adjustable heating control circuit of the present invention, the zero-crossing detection circuit comprises: a twelfth diode, a forty-ninth resistor, a fiftieth resistor, a third photocoupler and a forty-fourth resistor;

[0049] The anode of the twelfth diode is connected to the live wire of the AC input terminal, the cathode of the twelfth diode is connected to the first end of the third photoelectric coupler through the forty-ninth resistor, the second end of the third photoelectric coupler is connected to the neutral wire of the AC input terminal through the fiftieth resistor, the fourth end of the third photoelectric coupler is connected to the zero-crossing detection terminal of the control unit, the fourth end of the third photoelectric coupler is connected to the second end of the forty-fourth resistor, and the first end of the forty-fourth resistor is connected to the power supply circuit.

[0050] In the low-power continuously adjustable heating control circuit of the present invention, the low-continuous heating control mode includes: a chopping control mode or a chopping control mode.

[0051] In the low-power continuously adjustable heating control circuit described in the present invention, the low-power continuously adjustable heating control circuit is a single-tube topology structure.

[0052] The present invention also provides a heating device, comprising the low-power continuously adjustable heating control circuit mentioned above.

[0053] The present invention also provides a low-power continuously adjustable heating control method, comprising the following steps:

[0054] The input AC signal is detected by a zero-crossing detection circuit;

[0055] The control unit determines whether a zero-crossing detection signal output by the zero-crossing detection circuit is received;

[0056] If so, the control unit performs low-power continuous adjustable control according to the current low-continuous heating control mode in combination with the zero-crossing detection signal.

[0057] In the low-power continuously adjustable heating control method of the present invention, the low-continuous heating control mode includes: a chopping control mode or a chopping control mode.

[0058] In the low-power continuously adjustable heating control method of the present invention, if the low-continuous heating control mode is a chopping control mode, the control unit performs low-power continuously adjustable control according to the current low-continuous heating control mode in combination with the zero-crossing detection signal, including:

[0059] The control unit controls the driving circuit to operate in a half-cycle working and half-cycle stopping mode in each cycle according to the zero-crossing detection signal.

[0060] In the low-power continuously adjustable heating control method of the present invention, if the low-continuous heating control mode is a chopping control mode, the control unit performs low-power continuously adjustable control according to the current low-continuous heating control mode in combination with the zero-crossing detection signal, including:

[0061] The control unit controls the thyristor control circuit to operate in a half-cycle working and half-cycle stopping mode in each cycle according to the zero-crossing detection signal.

[0062] In the low-power continuously adjustable heating control method of the present invention, if the low-continuous heating control mode is a chopping control mode, the control unit performs low-power continuously adjustable control according to the current low-continuous heating control mode in combination with the zero-crossing detection signal, including:

[0063] The control unit divides each week into a plurality of sub-periods;

[0064] The control unit controls the driving circuit to operate in an intermittent mode in the plurality of sub-periods according to the zero-crossing detection signal.

[0065] In the low-power continuously adjustable heating control method of the present invention, if the low-continuous heating control mode is a chopping control mode, the control unit performs low-power continuously adjustable control according to the current low-continuous heating control mode in combination with the zero-crossing detection signal, including:

[0066] The control unit divides each week into a plurality of sub-periods;

[0067] The control unit controls the thyristor control circuit to operate in an intermittent mode in the plurality of sub-periods according to the zero-crossing detection signal.

[0068] The low-power continuously adjustable heating control circuit, method and heating device of the present invention have the following beneficial effects: including: input circuit, zero-crossing detection circuit, heating circuit, driving circuit and control unit; the input circuit performs rectification and filtering processing on the AC signal inputted from the AC input terminal, and outputs the rectified signal to the heating circuit; the zero-crossing detection circuit detects the AC signal inputted from the AC input terminal, and outputs the zero-crossing detection signal to the control unit when the zero-crossing signal is detected; the control unit drives and controls the driving circuit according to the current low-continuous heating control mode and the zero-crossing detection signal, so as to control the driving circuit to output the corresponding driving signal to the heating circuit, so that the heating circuit performs low-power heating according to the driving signal and the rectified signal. The present invention uses the zero-crossing detection signal to perform low-power heating control, which can reduce the average value of power, reduce ripple, avoid frequent sudden changes in power, and has a simple circuit structure, small size and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0070] Figure 1 It is a principle block diagram of Embodiment 1 of a low-power continuously adjustable heating control circuit provided by the present invention;

[0071] Figure 2 It is a principle block diagram of Embodiment 2 of a low-power continuously adjustable heating control circuit provided by the present invention;

[0072] Figures 3 to 6 It is a circuit diagram of a low-power continuously adjustable heating control circuit provided by the present invention;

[0073] Figure 7 It is a flow chart of the low-power continuously adjustable heating control method provided by the present invention. DETAILED DESCRIPTION

[0074] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0075] In order to solve the problems that the single-tube topology structure in the existing electromagnetic heating control board has frequent power mutations during continuous low-power heating, affecting the user experience, and the half-bridge topology structure has a complex structure, resulting in a large system volume and high cost, etc., the present invention provides a low-power continuously adjustable heating control circuit. The low-power continuously adjustable heating control circuit still adopts a simple single-tube topology structure and can greatly reduce the power average value, that is, the power mutation is smaller, the power ripple is smaller, and the user experience is effectively improved.

[0076] Specifically, refer to Figure 1 , which is a principle block diagram of Embodiment 1 of the low-power continuously adjustable heating control circuit provided by the present invention.

[0077] like Figure 1 As shown, the low-power continuously adjustable heating control circuit includes: an input circuit 10 , a zero-crossing detection circuit 30 , a heating circuit 20 , a driving circuit 90 and a control unit 80 .

[0078] The input end of the input circuit 10 is connected to the AC input end, the output end of the input circuit 10 is connected to the input end of the heating circuit 20, the control end of the heating circuit 20 is connected to the output end of the driving circuit 90, the input end of the driving circuit 90 is connected to the driving control end of the control unit 80, the detection end of the zero-crossing detection circuit 30 is connected to the AC input end, and the output end of the zero-crossing detection circuit 30 is connected to the zero-crossing detection end of the control unit 80.

[0079] The input circuit 10 is used to rectify and filter the AC signal input from the AC input terminal, and output the rectified signal to the heating circuit 20 .

[0080] Optional, such as Figure 1 As shown, in this embodiment, the input circuit 10 includes: an EMC filter circuit 101 and a rectifier filter circuit 102. The input end of the EMC filter circuit 101 is connected to the AC input end, the output end of the EMC filter circuit 101 is connected to the input end of the rectifier filter circuit 102, and the output end of the rectifier filter circuit 102 is connected to the input end of the heating circuit 20.

[0081] In the embodiment of the present invention, the EMC filter circuit 101 is used to perform EMC filtering on the AC signal connected from the AC input terminal to ensure the stability of the input signal and filter out interference.

[0082] In the embodiment of the present invention, the rectifying and filtering circuit 102 is used to rectify the signal after being filtered by the EMC filtering circuit 101, and transmit the rectified signal to the subsequent heating circuit 20 after another RC filtering.

[0083] The zero-crossing detection circuit 30 is used to detect the AC signal input from the AC input terminal, and output a zero-crossing detection signal to the control unit 80 when a zero-crossing signal is detected.

[0084] The control unit 80 is used to drive and control the drive circuit 90 in combination with the zero-crossing detection signal according to the current low-continuous heating control mode, so as to control the drive circuit 90 to output the corresponding drive signal to the heating circuit 20, so that the heating circuit 20 performs low-power heating according to the drive signal and the rectifier signal. It can be understood that in the embodiment of the present invention, the zero-crossing detection circuit 30 is set to perform zero-crossing detection on the input AC signal, wherein the zero-crossing detection signal output by the zero-crossing detection circuit 30 is used as a reference signal for the control unit 80 to adjust the power, so that when low-power continuous adjustment is required, electromagnetic induction oscillation heating is performed according to the zero-crossing detection signal, thereby realizing low-power continuous adjustment. Optionally, in the embodiment of the present invention, the low-continuous heating control mode of the drive circuit 90 by the control unit 80 can be: a chopped wave control mode or a chopping wave control mode.

[0085] Among them, if the chopped wave control mode is adopted, the control unit 80 controls the driving circuit 90 to work in a half-cycle working and half-cycle stopping mode in each cycle according to the zero-crossing detection signal. For example, taking the mains power of 50Hz as an example, the half-cycle time is 10ms, and the control is performed with every 10ms as a cycle. If the current 10ms oscillates, the next 10ms stops, that is, whether to perform electromagnetic induction heating oscillation can be determined in each 10ms cycle. For example, if the power is set to 400W, 1 cycle oscillates, and 1 cycle stops. Therefore, the average value of the power can be effectively reduced, and the chopped wave control is adopted, the system impact is small, and the mutation is small.

[0086] If the chopping control mode is adopted, the control unit 80 controls the driving circuit 90 to work in a half-cycle working and half-cycle stopping mode in each cycle according to the zero-crossing detection signal. For example, taking the mains power of 50Hz as an example, the half-cycle time is 10ms, and each 10ms cycle can be divided into several sub-cycles for low-power heating oscillation control. For example, the power is set to 400W, and the half cycle is 10ms. The half cycle is divided into 10 small heating oscillation cycles (sub-cycles), and the time of each sub-cycle is 1ms, 1 cycle oscillation, and 1 cycle stop, so the average value of the power is lower and the power ripple is small.

[0087] Furthermore, if Figure 1 As shown, the low-power continuously adjustable heating control circuit further includes: a current detection circuit 40 , which is respectively connected to the rectifying and filtering circuit 102 and the control unit 80 , and is used for current detection and outputting a current detection signal to the control unit 80 .

[0088] Furthermore, if Figure 1As shown, the low-power continuously adjustable heating control circuit further includes: a voltage detection circuit 50 connected to the EMC filter circuit 101 and the control unit 80 respectively. The voltage detection circuit 50 is used to detect the input voltage and output a voltage detection signal to the control unit 80.

[0089] Furthermore, if Figure 1 As shown, the low-power continuously adjustable heating control circuit further includes: a resonant circuit 70 connected to the heating circuit 20 and the control unit 80 respectively. The resonant circuit 70 is used to resonate the heating signal of the heating circuit 20 and output the resonant signal to the control unit 80.

[0090] Furthermore, if Figure 1 As shown, the low-power continuously adjustable heating control circuit further includes: a power supply circuit 60 connected to the EMC filter circuit 101. The power supply circuit 60 is used to convert the input voltage and output a power supply signal.

[0091] refer to Figure 2 , which is a principle block diagram of Embodiment 2 of a low-power continuously adjustable heating control circuit provided in an embodiment of the present invention.

[0092] like Figure 2 As shown, based on the first embodiment, this embodiment may further include a thyristor control circuit 110 .

[0093] The thyristor control circuit 110 is connected to the input circuit 10 and the control unit 80 respectively. The thyristor control circuit 110 is used to be turned on or off according to the control of the control unit 80 to control the connection or disconnection between the input circuit 10 and the heating circuit 20.

[0094] Specifically, Figure 2 As shown, the thyristor control circuit 110 is arranged between the output end of the EMC filter circuit 101 and the input end of the rectifier filter circuit 102. When receiving the shutdown signal output by the control unit 80, the thyristor control circuit 110 is turned off. At this time, no signal flows into the heating circuit 20, and the heating circuit 20 stops heating; when receiving the conduction signal output by the control unit 80, the thyristor control circuit 110 is turned on. At this time, the signal filtered by the EMC filter circuit 101 is rectified and filtered by the rectifier filter circuit 102, and then input to the heating circuit 20, and the heating circuit 20 is heated.

[0095] Optionally, in the embodiment of the present invention, the low continuous heating control mode of the thyristor control circuit 110 by the control unit 80 may be a chopped wave control mode or a chopper control mode.

[0096] Among them, if the chopped wave control mode is adopted, the control unit 80 controls the thyristor control circuit 110 to work in a half-cycle working and half-cycle stopping mode in each cycle according to the zero-crossing detection signal. For example, taking the mains power of 50Hz as an example, the half-cycle time is 10ms, and the control is performed with every 10ms as a cycle. If the current 10ms oscillates, the next 10ms stops, that is, whether to perform electromagnetic induction heating oscillation can be determined in each 10ms cycle. For example, if the power is set to 400W, 1 cycle oscillates and 1 cycle stops. Therefore, the average value of the power can be effectively reduced, and the chopped wave control is adopted, the system impact is small and the mutation is small.

[0097] In this embodiment, by setting a thyristor control circuit 110 at the front end, the output can be shut down by turning off the thyristor control circuit 110 during the period when the electromagnetic induction heating oscillation is not working. At this time, the voltage after the rectifier and filter circuit 102 is zero, and the starting impact is small when the next cycle works.

[0098] If the chopping control mode is adopted, the control unit 80 controls the thyristor control circuit 110 to work in a half-cycle working and half-cycle stopping mode in each cycle according to the zero-crossing detection signal. For example, taking the mains power of 50Hz as an example, the half-cycle time is 10ms, and each 10ms cycle can be divided into several sub-cycles for low-power heating oscillation control. For example, the set power is 400W, the half cycle is 10ms, and the half cycle is divided into 10 small heating oscillation cycles (sub-cycles), each sub-cycle time is 1ms, 1 cycle oscillation, 1 cycle stop, therefore, the average value of the power is lower and the power ripple is small.

[0099] In this embodiment, by setting a thyristor control circuit 110 at the front end, the output can be shut down by turning off the thyristor control circuit 110 during the period when the electromagnetic induction heating oscillation is not working. At this time, the voltage after the rectifier and filter circuit 102 is zero, and the starting impact is small when the next cycle works.

[0100] refer to Figures 3 to 6 , which is a circuit diagram of an optional embodiment of a low-power continuously adjustable heating control circuit provided by the present invention.

[0101] In this embodiment, the low-power continuously adjustable heating control circuit may be provided with a thyristor control circuit 110 .

[0102] Specifically, Figures 3 to 6 As shown, the EMC filter circuit 101 includes: a varistor ZNR1, a first capacitor C1, an eighth resistor R8, a tenth resistor R10, a common mode inductor CT1, a ninth resistor R9, an eleventh resistor R11, a second capacitor C2, a seventh capacitor C7 and a sixth capacitor C6.

[0103] A first end of the varistor ZNR1 is connected to the live wire of the AC input end, a second end of the varistor ZNR1 is connected to the neutral wire of the AC input end, a first capacitor C1 is connected in parallel with the varistor ZNR1, a first end of the eighth resistor R8 is connected to the first end of the varistor ZNR1, a second end of the eighth resistor R8 is connected to the first end of the tenth resistor R10, a second end of the tenth resistor R10 is connected to the second end of the varistor ZNR1, a first end of the common-mode inductor CT1 is connected to the first end of the varistor ZNR1, a second end of the common-mode inductor CT1 is connected to the second end of the varistor ZNR1, a third end of the common-mode inductor CT1 is connected to the first end of the ninth resistor R9, the first end of the second capacitor C2 and the first end of the sixth capacitor C6, a second end of the common-mode inductor CT1 is connected to the second end of the eleventh resistor R11, the second end of the seventh capacitor C7 and the second end of the sixth capacitor C6, a second end of the ninth resistor R9 is connected to the first end of the eleventh resistor R11, a second end of the second capacitor C2 is connected to the first end of the seventh capacitor C7, and the first end and the second end of the sixth capacitor C6 are also connected to the rectifier and filter circuit 102 respectively.

[0104] The rectifying and filtering circuit 102 includes: a rectifying bridge D1, a second inductor L2 and an eighth capacitor C8.

[0105] The first input end of the rectifier bridge D1 is connected to the first end of the sixth capacitor C6, the second input end of the rectifier bridge D1 is connected to the second end of the sixth capacitor C6, the positive output end of the rectifier bridge D1 is connected to the first end of the second inductor L2, the second end of the second inductor L2 is connected to the first end of the eighth capacitor C8 and the input end of the heating circuit 20, the second end of the eighth capacitor C8 is grounded, and the negative output end of the rectifier bridge D1 is grounded through the detection resistor RT1.

[0106] The thyristor control circuit 110 includes: a fourth capacitor C4, a seventh resistor R7, a thyristor Q4, a second resistor R2, a third resistor R3, a first photocoupler IC1, a first resistor R1 and a first transistor Q1;

[0107] The first end of the fourth capacitor C4 is connected to the first end of the second resistor R2, the second end of the fourth capacitor C4 is connected to the first end of the second capacitor C2, the second end of the seventh resistor R7 is connected to the first end of the second capacitor C2, the first end of the seventh resistor R7 is connected to the first end of the second resistor R2, the second end of the second resistor R2 is connected to the sixth end of the first photocoupler IC1, the fourth end of the first photocoupler IC1 is connected to the output end of the thyristor Q4 through the third resistor R3, the input end (A1) of the thyristor Q4 is connected to the first end of the fourth capacitor C4, the output end (A2) of the thyristor Q4 is also connected to the rectifier and filter circuit 102, and the control end (G) of the thyristor Q4 is connected to the first end of the second resistor R2; the first end of the first photocoupler IC1 is connected to the second power supply output end of the power supply circuit 60 through the first resistor R1, the second end of the first photocoupler IC1 is connected to the collector of the first transistor Q1, the emitter of the first transistor Q1 is grounded, and the base of the first transistor Q1 is connected to the thyristor control end of the control unit (DIR pin of the controller U1).

[0108] like Figure 3 As shown, when the thyristor control circuit 110 is not provided, the first end of the sixth capacitor C6 is directly connected to the positive input end of the rectifier bridge D1.

[0109] In this embodiment, the heating circuit 20 includes: a heating coil L1, a fifth capacitor C5 and an IGBT tube IGBT1.

[0110] The first end of the heating coil L1 is connected to the second end of the second inductor L2, the second end of the heating coil L1 is connected to the first end of the IGBT tube IGBT1, the fifth capacitor C5 is connected in parallel with the heating coil L1, the second end of the IGBT tube IGBT1 is grounded, and the third end of the IGBT tube IGBT1 is connected to the output end of the drive circuit 90.

[0111] The driving circuit 90 includes: a fourteenth resistor R14, a third voltage regulator D3, a twelfth resistor R12, a second transistor Q2, a fifth transistor Q5, a fourth resistor R4, a fifth resistor R5, a third transistor Q3, a sixth resistor R6, a thirteenth resistor R13, a third capacitor C3 and a first filter capacitor EC1.

[0112] The first end of the twelfth resistor R12 is connected to the third end of the IGBT tube IGBT1, the second end of the twelfth resistor R12 is connected to the emitter of the second triode Q2 and the emitter of the fifth triode Q5, the first end of the fourteenth resistor R14 is connected to the first end of the twelfth resistor R12, the second end of the fourteenth resistor R14 and the anode of the third voltage-stabilizing tube D3 are grounded, and the cathode of the third voltage-stabilizing tube D3 is connected to the first end of the twelfth resistor R12; the collector of the fifth triode Q5 is grounded, the base of the fifth triode Q5 is connected to the base of the second triode Q2, the collector of the third triode Q3 and the second end of the fifth resistor R5, and the second triode Q2 The collector is connected to the first power supply output terminal of the power supply circuit 60 through the fourth resistor R4; the first end of the fifth resistor R5 is connected to the first power supply output terminal of the power supply circuit 60, the emitter of the third transistor Q3 is grounded, the base of the third transistor Q3 is connected to the first power supply output terminal of the power supply circuit 60 through the sixth resistor R6, the first end of the third capacitor C3 is connected to the first power supply output terminal of the power supply circuit 60, the second end of the third capacitor C3 is grounded, the first filter capacitor EC1 is connected to the third capacitor C3 in parallel; the base of the third transistor Q3 is also connected to the drive control end of the control unit 80 (PPG pin of the controller U1) through the thirteenth resistor R13.

[0113] like Figure 4 As shown, the voltage detection circuit 50 includes: a second diode D2, a fifth diode D5, a sixteenth resistor R16, a seventeenth resistor R17, a twenty-first resistor R21, a twenty-second resistor R22, a tenth capacitor C10, a twenty-third resistor R23, a twenty-fourth resistor R24 ​​and an eleventh capacitor C11.

[0114] The anode of the second diode D2 is connected to the fourth end of the common-mode inductor CT1, the anode of the fifth diode D5 is connected to the third end of the common-mode inductor CT1, the cathode of the second diode D2 and the cathode of the fifth diode D5 are connected and connected to the input end of the power supply circuit 60; the first end of the sixteenth resistor R16 is connected to the cathode of the second diode D2 and the cathode of the fifth diode D5, the second end of the sixteenth resistor R16 is connected to the ground through the twenty-first resistor R21 and the twenty-third resistor R23 in sequence, the tenth capacitor C10 is connected in parallel with the twenty-third resistor R23, and the sixteenth resistor R16 is connected to the second The connection end of the eleventh resistor R21 is also connected to the first voltage detection end of the control unit 80 (the V_T pin of the controller U1); the first end of the seventeenth resistor R17 is connected to the cathode of the second diode D2 and the cathode of the fifth diode D5, the second end of the seventeenth resistor R17 is grounded through the twenty-second resistor R22 and the twenty-fourth resistor R24 ​​in sequence, the eleventh capacitor C11 is connected to the twenty-fourth resistor R24 ​​in parallel, and the connection end of the seventeenth resistor R17 and the twenty-second resistor R22 is also connected to the second voltage detection end of the control unit 80 (the C1P pin of the controller U1).

[0115] like Figure 4 As shown, the power supply circuit 60 includes: a fourth diode D4, a second filter capacitor EC2, a fifteenth resistor R15, an eighteenth resistor R18, a ninth capacitor C9, a sixth diode D6, a transformer TS1, a first power supply chip IC2, a seventh diode D7, an eighth diode D8, a third filter capacitor EC3, a ninth diode D9, a tenth voltage regulator D10, a twentieth capacitor C20, a fourth filter capacitor EC4, a twenty-first capacitor C21, a sixth filter capacitor EC6, a twenty-second capacitor C22, a second power supply chip U2, a seventh filter capacitor EC7 and a twenty-fourth capacitor C24.

[0116] The anode of the fourth diode D4 is connected to the cathode of the second diode D2 and the cathode of the fifth diode D5, the cathode of the fourth diode D4 is grounded via the fifteenth resistor R15 and the second filter capacitor EC2 in sequence, the first end of the eighteenth resistor R18 is connected to the connection end of the fifteenth resistor R15 and the second filter capacitor EC2, the second end of the eighteenth resistor R18 is connected to the cathode of the sixth diode D6, the ninth capacitor C9 is connected in parallel with the eighteenth resistor R18, the anode of the sixth diode D6 is connected to the first input end of the transformer TS1, and the second input end of the transformer TS1 is connected to the first end of the eighteenth resistor R18.

[0117] The first output end of the transformer TS1 is connected to the anode of the eighth diode D8, the second output end of the transformer TS1 is connected to the anode of the seventh diode D7, and the third output end of the transformer TS1 is grounded; the negative end of the third filter capacitor EC3 is grounded, the positive end of the third filter capacitor EC3 is connected to the fourth pin of the first power supply chip IC2, the eighth pin of the first power supply chip IC2 is connected to the anode of the sixth diode D6, the fourth pin of the first power supply chip IC2 is connected to the cathode of the ninth diode D9, the third pin of the first power supply chip IC2 is connected to the anode of the tenth voltage regulator tube D10 and the first end of the twentieth capacitor C20, and the eighth pin of the first power supply chip IC2 is connected to the anode of the sixth diode D6. The second end of capacitor C20 is grounded, the anode of the ninth diode D9 is connected to the cathode of the tenth voltage regulator diode D10, the first pin and the second pin of the first power supply chip IC2 are short-circuited and connected to the ground; the cathode of the eighth diode D8 is connected to the positive end of the fourth filter capacitor EC4, the negative end of the fourth filter capacitor EC4 is grounded, the first end of the twenty-first capacitor C21 is connected to the positive end of the fourth filter capacitor EC4 and the anode of the ninth diode D9, the second end of the twenty-first capacitor C21 is grounded, and the connection end between the first end of the twenty-first capacitor C21 and the positive end of the fourth filter capacitor EC4 is the first power supply output end (VQQ) of the power supply circuit 60.

[0118] The cathode of the seventh diode D7 is connected to the first pin of the second power supply chip U2 and the positive end of the sixth filter capacitor EC6, the negative end of the sixth filter capacitor EC6 is grounded, the twenty-second capacitor C22 is connected in parallel with the sixth filter capacitor EC6, the second pin of the second power supply chip U2 is grounded, the third pin of the second power supply chip U2 is the second power supply output terminal (VCC) of the power supply circuit 60, the third pin of the second power supply chip U2 is also grounded through the seventh filter capacitor EC7, and the twenty-fourth capacitor C24 is connected in parallel with the seventh filter capacitor EC7.

[0119] like Figure 3 As shown, the current detection circuit 40 includes: a thirty-first resistor R31, a fifteenth capacitor C15, a sixteenth capacitor C16, a seventeenth capacitor C17, a thirty-second resistor R32, a thirty-seventh resistor R37, an adjustable resistor VR1 and a detection resistor RT1.

[0120] The first end of the detection resistor RT1 is connected to the negative output end of the rectifier bridge D1, the second end of the detection resistor RT1 is grounded, the first end of the thirty-first resistor R31 is connected to the second end of the detection resistor RT1, the second end of the thirty-first resistor R31 is connected to the first end of the fifteenth resistor R15, the second end of the fifteenth resistor R15 is grounded, the second end of the thirty-first resistor R31 is also connected to the first current detection end of the control unit 80 (the A1P pin of the controller U1), the first end of the sixteenth capacitor C16 is connected to the first end of the seventeenth capacitor C17 and the first end of the thirty-second resistor R32, the second end of the sixteenth resistor R16 and the second end of the seventeenth resistor R17 are grounded, the second end of the thirty-second resistor R32 is connected to the first end of the thirty-seventh resistor R37, the second end of the thirty-seventh resistor R37 is grounded, and the adjustable resistor VR1 is connected in parallel with the thirty-seventh resistor R37; the first end of the sixteenth capacitor C16 is also connected to the second current detection end of the control unit 80 (the A1N pin of the controller U1).

[0121] like Figure 3 As shown, the resonant circuit 70 includes: a nineteenth resistor R19, a twentieth resistor R20, a twenty-fifth resistor R25, a twenty-sixth resistor R26, a thirty-third resistor R33, a thirtieth resistor R30, a thirty-fourth resistor R34, a thirty-eighth resistor R38, a thirteenth capacitor C13, a twelfth capacitor C12 and a fourteenth capacitor C14.

[0122] The first end of the nineteenth resistor R19 is connected to the first end of the heating coil L1, the second end of the nineteenth resistor R19 is grounded through the twenty-fifth resistor R25 and the thirty-third resistor R33 in sequence, and the connection end of the twenty-fifth resistor R25 and the thirty-third resistor R33 is connected to the control unit 80 (the C0N pin of the controller U1); the first end of the twentieth resistor R20 is connected to the second end of the heating coil L1, the second end of the twentieth resistor R20 is grounded through the twenty-sixth resistor R26, the thirty-fourth resistor R34 and the thirty-eighth resistor R38 in sequence, the first end of the thirtieth resistor R30 is connected to the connection end of the twenty-sixth resistor R26 and the thirty-fourth resistor R34, the second end of the thirtieth resistor R30 is connected to the first end of the twelfth capacitor C12 and the first end of the thirteenth capacitor C13, the second end of the thirteenth capacitor C13 is grounded, the second end of the twelfth capacitor C12 is grounded through the fourteenth capacitor C14, the second end of the thirtieth resistor R30 is connected to the control unit 80 (the C0P pin of the controller U1), and the second end of the twelfth capacitor C12 is connected to the control unit 80 (the C0N pin of the controller U1).

[0123] like Figure 6 As shown, the zero-crossing detection circuit 30 includes: a twelfth diode D12, a forty-ninth resistor R49, a fiftieth resistor R50, a third photocoupler U3 and a forty-fourth resistor R44.

[0124] The anode of the twelfth diode D12 is connected to the live wire of the AC input terminal, the cathode of the twelfth diode D12 is connected to the first end of the third photocoupler U3 through the forty-ninth resistor R49, the second end of the third photocoupler U3 is connected to the neutral line of the AC input terminal through the fiftieth resistor R50, the fourth end of the third photocoupler U3 is connected to the zero-crossing detection end of the control unit 80 (the ZERO pin of the controller U1), the fourth end of the third photocoupler U3 is connected to the second end of the forty-fourth resistor R44, and the first end of the forty-fourth resistor R44 is connected to the power supply circuit 60.

[0125] like Figure 5 As shown, the control unit 80 includes: a controller U1.

[0126] The present invention further provides a heating device, which may include the low-power continuously adjustable heating control circuit disclosed in the embodiment of the present invention. Optionally, the heating device includes but is not limited to an electromagnetic heater, such as an electromagnetic cooker.

[0127] refer to Figure 7 , is a flow chart of an optional embodiment of a low-power continuously adjustable heating control method provided by the present invention. The low-power continuously adjustable heating control method can be implemented by a low-power continuously adjustable heating control circuit disclosed in an embodiment of the present invention.

[0128] Specifically, Figure 7 As shown, the low-power continuously adjustable heating control method comprises the following steps:

[0129] Step S701 : Detect the input AC signal through the zero-crossing detection circuit 30 .

[0130] Step S702: The control unit 80 determines whether a zero-crossing detection signal output by the zero-crossing detection circuit is received.

[0131] Step S703: If yes, the control unit 80 performs low-power continuous adjustable control according to the current low-continuous heating control mode and the zero-crossing detection signal. Optionally, the low-continuous heating control mode includes: a chopped wave control mode or a chopping wave control mode.

[0132] In some embodiments, if the low continuous heating control mode is a chopping control mode, the control unit 80 performs low-power continuous adjustable control according to the current low continuous heating control mode in combination with the zero-crossing detection signal, including: the control unit 80 controls the drive circuit 90 to operate in a half-cycle working and half-cycle stopping mode in each cycle according to the zero-crossing detection signal.

[0133] For example, taking the mains power of 50Hz as an example, the half-cycle time is 10ms, and the control is carried out with every 10ms as a cycle. If the current 10ms oscillates, the next 10ms will stop, that is, whether to perform electromagnetic induction heating oscillation can be determined within each 10ms cycle. If the set power is 400W, 1 cycle oscillates and 1 cycle stops. Therefore, the average power value can be effectively reduced, and the use of chopped wave control has small system impact and small mutation.

[0134] In some embodiments, if the low continuous heating control mode is a chopping control mode, the control unit 80 performs low-power continuous adjustable control according to the current low continuous heating control mode in combination with the zero-crossing detection signal, including: the control unit 80 divides each cycle into multiple sub-cycles; the control unit 80 controls the drive circuit 90 to operate in an intermittent mode in multiple sub-cycles according to the zero-crossing detection signal.

[0135] For example, taking the mains power of 50Hz as an example, the half cycle time is 10ms, and each 10ms cycle can be divided into several sub-cycles for low-power heating oscillation control. For example, the set power is 400W, the half cycle is 10ms, and the half cycle is divided into 10 small heating oscillation cycles (sub-cycles), each sub-cycle time is 1ms, 1 cycle oscillation, 1 cycle stop, therefore, the average power value is lower and the power ripple is small.

[0136] In some embodiments, if the low continuous heating control mode is a chopping control mode, the control unit 80 performs low power continuous adjustable control according to the current low continuous heating control mode in combination with the zero crossing detection signal, including: the control unit 80 controls the thyristor control circuit 110 to operate in a half-cycle working and half-cycle stopping mode in each cycle according to the zero crossing detection signal.

[0137] For example, taking the mains power of 50Hz as an example, the half-cycle time is 10ms, and the control is carried out with every 10ms as a cycle. If the current 10ms oscillates, the next 10ms will stop, that is, whether to perform electromagnetic induction heating oscillation can be determined within each 10ms cycle. If the set power is 400W, 1 cycle oscillates and 1 cycle stops. Therefore, the average power value can be effectively reduced, and the use of chopped wave control has small system impact and small mutation.

[0138] In some embodiments, if the low continuous heating control mode is a chopping control mode, the control unit 80 performs low-power continuous adjustable control according to the current low continuous heating control mode in combination with the zero-crossing detection signal, including: the control unit 80 divides each week into multiple sub-cycles; the control unit 80 controls the thyristor control circuit 110 to operate in an intermittent mode in multiple sub-cycles according to the zero-crossing detection signal.

[0139] For example, taking the mains power of 50Hz as an example, the half cycle time is 10ms, and each 10ms cycle can be divided into several sub-cycles for low-power heating oscillation control. For example, the set power is 400W, the half cycle is 10ms, and the half cycle is divided into 10 small heating oscillation cycles (sub-cycles), each sub-cycle time is 1ms, 1 cycle oscillation, 1 cycle stop, therefore, the average power value is lower and the power ripple is small.

[0140] Among them, by setting a thyristor control circuit 110 at the front end, the output can be turned off by turning off the thyristor control circuit 110 during the period when the electromagnetic induction heating oscillation is not working. At this time, the voltage after the rectifier and filter circuit 102 is zero, and when the next cycle works, the starting impact is small.

[0141] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0142] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0143] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0144] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot limit the scope of protection of the present invention. All equivalent changes and modifications made to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A low-power continuously adjustable heating control circuit, characterized in that: Continuous low-power adjustable heating applied to a single-tube topology structure, including: an input circuit, a zero-crossing detection circuit, a heating circuit, a driving circuit and a control unit; The input end of the input circuit is connected to the AC input end, the output end of the input circuit is connected to the input end of the heating circuit, the control end of the heating circuit is connected to the output end of the drive circuit, the input end of the drive circuit is connected to the drive control end of the control unit, the detection end of the zero-crossing detection circuit is connected to the AC input end, and the output end of the zero-crossing detection circuit is connected to the zero-crossing detection end of the control unit; The input circuit is used to perform rectification and filtering processing on the AC signal input from the AC input terminal, and output the rectified signal to the heating circuit; The zero-crossing detection circuit is used to detect the AC signal input from the AC input terminal, and output a zero-crossing detection signal to the control unit when a zero-crossing signal is detected; The control unit is used to drive and control the drive circuit according to the current low-continuous heating control mode in combination with the zero-crossing detection signal, so as to control the drive circuit to output a corresponding drive signal to the heating circuit, so that the heating circuit performs low-power heating according to the drive signal and the rectified signal; the control unit is used to use the zero-crossing detection signal as a reference signal for power adjustment, so as to perform electromagnetic induction oscillation heating according to the zero-crossing detection signal when performing low-power continuous adjustment; The control unit is used to control the drive of the drive circuit to a low continuous heating control mode, and the low continuous heating control mode includes: a chopping control mode or a chopping control mode; and if the chopping control mode is adopted, the control unit is used to control the drive circuit to work in a half-cycle working and half-cycle stopping mode in each cycle according to the zero-crossing detection signal; if the chopping control mode is adopted, the control unit is used to control the drive circuit to work in a half-cycle working and half-cycle stopping mode in each cycle according to the zero-crossing detection signal.

2. The low-power continuously adjustable heating control circuit according to claim 1 is characterized in that: The input circuit includes: an EMC filter circuit and a rectifier filter circuit; The input end of the EMC filter circuit is connected to the AC input end, the output end of the EMC filter circuit is connected to the input end of the rectifier filter circuit, and the output end of the rectifier filter circuit is connected to the input end of the heating circuit.

3. The low-power continuously adjustable heating control circuit according to claim 2 is characterized in that: Also includes: Thyristor control circuit; The thyristor control circuit is connected to the input circuit and the control unit respectively; The thyristor control circuit is used to be turned on or off according to the control of the control unit to control the connection or disconnection between the input circuit and the heating circuit.

4. The low-power continuously adjustable heating control circuit according to claim 3 is characterized in that: Also includes: Current detection circuit; The circuits are respectively connected to the rectifying and filtering circuit and the control unit, and are used for current detection and outputting current detection signals to the control unit.

5. The low-power continuously adjustable heating control circuit according to claim 4, characterized in that: Also includes: A voltage detection circuit connected to the EMC filter circuit and the control unit respectively; The voltage detection circuit is used to detect the input voltage and output a voltage detection signal to the control unit.

6. The low-power continuously adjustable heating control circuit according to claim 5, characterized in that: Also includes: a resonant circuit connected to the heating circuit and the control unit respectively; The resonant circuit is used to perform resonance processing on the heating signal of the heating circuit and output the resonance signal to the control unit.

7. The low-power continuously adjustable heating control circuit according to claim 6, characterized in that: Also includes: A power supply circuit connected to the EMC filter circuit; The power supply circuit is used to convert the input voltage and output a power supply signal.

8. The low-power continuously adjustable heating control circuit according to claim 7, characterized in that: The EMC filter circuit comprises: a varistor, a first capacitor, an eighth resistor, a tenth resistor, a common mode inductor, a ninth resistor, an eleventh resistor, a second capacitor, a seventh capacitor and a sixth capacitor; The first end of the varistor is connected to the live wire of the AC input end, the second end of the varistor is connected to the neutral wire of the AC input end, the first capacitor is connected to the varistor in parallel, the first end of the eighth resistor is connected to the first end of the varistor, the second end of the eighth resistor is connected to the first end of the tenth resistor, the second end of the tenth resistor is connected to the second end of the varistor, the first end of the common-mode inductor is connected to the first end of the varistor, the second end of the common-mode inductor is connected to the second end of the varistor, the third end of the common-mode inductor is connected to the first end of the ninth resistor, the first end of the second capacitor and the first end of the sixth capacitor, the second end of the common-mode inductor is connected to the second end of the eleventh resistor, the second end of the seventh capacitor and the second end of the sixth capacitor, the second end of the ninth resistor is connected to the first end of the eleventh resistor, the second end of the second capacitor is connected to the first end of the seventh capacitor, the first end of the sixth capacitor is connected to the rectifier and filter circuit through the thyristor control circuit, and the second end of the sixth capacitor is connected to the rectifier and filter circuit.

9. The low-power continuously adjustable heating control circuit according to claim 8, characterized in that: The thyristor control circuit comprises: a fourth capacitor, a seventh resistor, a thyristor, a second resistor, a third resistor, a first photocoupler, a first resistor and a first transistor; The first end of the fourth capacitor is connected to the first end of the second resistor, the second end of the fourth capacitor is connected to the first end of the second capacitor, the second end of the seventh resistor is connected to the first end of the second capacitor, the first end of the seventh resistor is connected to the first end of the second resistor, the second end of the second resistor is connected to the sixth end of the first photoelectric coupler, the fourth end of the first photoelectric coupler is connected to the output end of the thyristor through the third resistor, the input end of the thyristor is connected to the first end of the fourth capacitor, the output end of the thyristor is also connected to the rectifier and filter circuit, and the control end of the thyristor is connected to the first end of the second resistor; the first end of the first photoelectric coupler is connected to the second power supply output end of the power supply circuit through the first resistor, the second end of the first photoelectric coupler is connected to the collector of the first transistor, the emitter of the first transistor is grounded, and the base of the first transistor is connected to the thyristor control end of the control unit.

10. The low-power continuously adjustable heating control circuit according to claim 9, characterized in that: The rectification and filtering circuit comprises: a rectifier bridge, a second inductor and an eighth capacitor; The first input end of the rectifier bridge is connected to the output end of the thyristor, the second input end of the rectifier bridge is connected to the second end of the sixth capacitor, the positive output end of the rectifier bridge is connected to the first end of the second inductor, the second end of the second inductor is connected to the first end of the eighth capacitor and the input end of the heating circuit, the second end of the eighth capacitor is grounded, and the negative output end of the rectifier bridge is grounded through a detection resistor.

11. The low-power continuously adjustable heating control circuit according to claim 10, characterized in that: The heating circuit comprises: a heating coil, a fifth capacitor and an IGBT tube; The first end of the heating coil is connected to the second end of the second inductor, the second end of the heating coil is connected to the first end of the IGBT tube, the fifth capacitor is connected in parallel with the heating coil, the second end of the IGBT tube is grounded, and the third end of the IGBT tube is connected to the output end of the drive circuit.

12. The low-power continuously adjustable heating control circuit according to claim 11, characterized in that: The driving circuit includes: a fourteenth resistor, a third voltage-stabilizing diode, a twelfth resistor, a second triode, a fifth triode, a fourth resistor, a fifth resistor, a third triode, a sixth resistor, a thirteenth resistor, a third capacitor and a first filter capacitor; The first end of the twelfth resistor is connected to the third end of the IGBT tube, the second end of the twelfth resistor is connected to the emitter of the second transistor and the emitter of the fifth transistor, the first end of the fourteenth resistor is connected to the first end of the twelfth resistor, the second end of the fourteenth resistor and the anode of the third voltage regulator tube are grounded, and the cathode of the third voltage regulator tube is connected to the first end of the twelfth resistor; The collector of the fifth transistor is grounded, the base of the fifth transistor is connected to the base of the second transistor, the collector of the third transistor and the second end of the fifth resistor, the collector of the second transistor is connected to the first power supply output end of the power supply circuit through the fourth resistor; the first end of the fifth resistor is connected to the first power supply output end of the power supply circuit, the emitter of the third transistor is grounded, the base of the third transistor is connected to the first power supply output end of the power supply circuit through the sixth resistor, the first end of the third capacitor is connected to the first power supply output end of the power supply circuit, the second end of the third capacitor is grounded, and the first filter capacitor is connected in parallel with the third capacitor; the base of the third transistor is also connected to the drive control end of the control unit through the thirteenth resistor.

13. The low-power continuously adjustable heating control circuit according to claim 8, characterized in that: The voltage detection circuit includes: a second diode, a fifth diode, a sixteenth resistor, a seventeenth resistor, a twenty-first resistor, a twenty-second resistor, a tenth capacitor, a twenty-third resistor, a twenty-fourth resistor and an eleventh capacitor; The anode of the second diode is connected to the fourth end of the common-mode inductor, the anode of the fifth diode is connected to the third end of the common-mode inductor, and the cathode of the second diode and the cathode of the fifth diode are connected and connected to the input end of the power supply circuit; A first end of the sixteenth resistor is connected to the cathode of the second diode and the cathode of the fifth diode, a second end of the sixteenth resistor is grounded via the twenty-first resistor and the twenty-third resistor in sequence, the tenth capacitor is connected to the twenty-third resistor in parallel, and a connection end of the sixteenth resistor and the twenty-first resistor is also connected to a first voltage detection end of the control unit; The first end of the seventeenth resistor is connected to the cathode of the second diode and the cathode of the fifth diode, the second end of the seventeenth resistor is grounded through the twenty-second resistor and the twenty-fourth resistor in sequence, the eleventh capacitor is connected to the twenty-fourth resistor in parallel, and the connecting end of the seventeenth resistor and the twenty-second resistor is also connected to the second voltage detection terminal of the control unit.

14. The low-power continuously adjustable heating control circuit according to claim 13, characterized in that: The power supply circuit includes: a fourth diode, a second filter capacitor, a fifteenth resistor, an eighteenth resistor, a ninth capacitor, a sixth diode, a transformer, a first power supply chip, a seventh diode, an eighth diode, a third filter capacitor, a ninth diode, a tenth voltage regulator, a twentieth capacitor, a fourth filter capacitor, a twenty-first capacitor, a sixth filter capacitor, a twenty-second capacitor, a second power supply chip, a seventh filter capacitor and a twenty-fourth capacitor; The anode of the fourth diode is connected to the cathode of the second diode and the cathode of the fifth diode, the cathode of the fourth diode is grounded through the fifteenth resistor and the second filter capacitor in sequence, the first end of the eighteenth resistor is connected to the connection end of the fifteenth resistor and the second filter capacitor, the second end of the eighteenth resistor is connected to the cathode of the sixth diode, the ninth capacitor is connected in parallel with the eighteenth resistor, the anode of the sixth diode is connected to the first input end of the transformer, and the second input end of the transformer is connected to the first end of the eighteenth resistor; The first output end of the transformer is connected to the anode of the eighth diode, the second output end of the transformer is connected to the anode of the seventh diode, and the third output end of the transformer is grounded; the negative end of the third filter capacitor is grounded, the positive end of the third filter capacitor is connected to the fourth pin of the first power supply chip, the eighth pin of the first power supply chip is connected to the anode of the sixth diode, the fourth pin of the first power supply chip is connected to the cathode of the ninth diode, the third pin of the first power supply chip is connected to the anode of the tenth voltage regulator tube and the first end of the twentieth capacitor, the second end of the twentieth capacitor is grounded, the anode of the ninth diode is connected to the cathode of the tenth voltage regulator tube, and the first pin and the second pin of the first power supply chip are short-circuited and connected to the ground; The cathode of the eighth diode is connected to the positive end of the fourth filter capacitor, the negative end of the fourth filter capacitor is grounded, the first end of the twenty-first capacitor is connected to the positive end of the fourth filter capacitor and the anode of the ninth diode, the second end of the twenty-first capacitor is grounded, and the connection end between the first end of the twenty-first capacitor and the positive end of the fourth filter capacitor is the first power supply output end of the power supply circuit; The cathode of the seventh diode is connected to the first pin of the second power supply chip and the positive end of the sixth filter capacitor, the negative end of the sixth filter capacitor is grounded, the twenty-second capacitor is connected in parallel with the sixth filter capacitor, the second pin of the second power supply chip is grounded, the third pin of the second power supply chip is the second power supply output end of the power supply circuit, the third pin of the second power supply chip is also grounded through the seventh filter capacitor, and the twenty-fourth capacitor is connected in parallel with the seventh filter capacitor.

15. The low-power continuously adjustable heating control circuit according to claim 14, characterized in that: The current detection circuit comprises: a thirty-first resistor, a fifteenth capacitor, a sixteenth capacitor, a seventeenth capacitor, a thirty-second resistor, a thirty-seventh resistor, an adjustable resistor and a detection resistor; The first end of the detection resistor is connected to the negative output end of the rectifier bridge, the second end of the detection resistor is grounded, the first end of the thirty-first resistor is connected to the second end of the detection resistor, the second end of the thirty-first resistor is connected to the first end of the fifteenth resistor, the second end of the fifteenth resistor is grounded, the second end of the thirty-first resistor is also connected to the first current detection end of the control unit, the first end of the sixteenth capacitor is connected to the first end of the seventeenth capacitor and the first end of the thirty-second resistor, the second end of the sixteenth resistor and the second end of the seventeenth resistor are grounded, the second end of the thirty-second resistor is connected to the first end of the thirty-seventh resistor, the second end of the thirty-seventh resistor is grounded, and the adjustable resistor is connected in parallel with the thirty-seventh resistor.

16. The low-power continuously adjustable heating control circuit according to claim 11, characterized in that: The resonant circuit comprises: a nineteenth resistor, a twentieth resistor, a twenty-fifth resistor, a twenty-sixth resistor, a thirty-third resistor, a thirtieth resistor, a thirty-fourth resistor, a thirty-eighth resistor, a thirteenth capacitor, a twelfth capacitor and a fourteenth capacitor; The first end of the nineteenth resistor is connected to the first end of the heating coil, the second end of the nineteenth resistor is grounded via the twenty-fifth resistor and the thirty-third resistor in sequence, and the connection end of the twenty-fifth resistor and the thirty-third resistor is connected to the control unit; The first end of the 20th resistor is connected to the second end of the heating coil, the second end of the 20th resistor is grounded via the 26th resistor, the 34th resistor and the 38th resistor in sequence, the first end of the 30th resistor is connected to the connecting end of the 26th resistor and the 34th resistor, the second end of the 30th resistor is connected to the first end of the twelfth capacitor and the first end of the thirteenth capacitor, the second end of the thirteenth capacitor is grounded, the second end of the twelfth capacitor is grounded via the fourteenth capacitor, the second end of the 30th resistor is connected to the control unit, and the second end of the twelfth capacitor is connected to the control unit.

17. The low-power continuously adjustable heating control circuit according to claim 7, characterized in that: The zero-crossing detection circuit comprises: a twelfth diode, a forty-ninth resistor, a fiftieth resistor, a third photocoupler and a forty-fourth resistor; The anode of the twelfth diode is connected to the live wire of the AC input terminal, the cathode of the twelfth diode is connected to the first end of the third photoelectric coupler through the forty-ninth resistor, the second end of the third photoelectric coupler is connected to the neutral wire of the AC input terminal through the fiftieth resistor, the fourth end of the third photoelectric coupler is connected to the zero-crossing detection terminal of the control unit, the fourth end of the third photoelectric coupler is connected to the second end of the forty-fourth resistor, and the first end of the forty-fourth resistor is connected to the power supply circuit.

18. The low-power continuously adjustable heating control circuit according to any one of claims 1 to 17, characterized in that: The low continuous heating control mode includes: a chopping control mode or a chopped wave control mode.

19. The low-power continuously adjustable heating control circuit according to claim 18, characterized in that: The low-power continuously adjustable heating control circuit is a single-tube topology structure.

20. A heating device, characterized in that: It comprises the low-power continuously adjustable heating control circuit as described in any one of claims 1-19.

21. A low-power continuously adjustable heating control method, applied to the low-power continuously adjustable heating control circuit according to any one of claims 1 to 19, characterized in that: The following steps are involved: The input AC signal is detected by a zero-crossing detection circuit; The control unit determines whether a zero-crossing detection signal output by the zero-crossing detection circuit is received; If so, the control unit performs low-power continuous adjustable control according to the current low-continuous heating control mode in combination with the zero-crossing detection signal.

22. The low-power continuously adjustable heating control method according to claim 21, characterized in that: The low continuous heating control mode includes: a chopping control mode or a chopped wave control mode.

23. The low-power continuously adjustable heating control method according to claim 22, characterized in that: If the low-continuous heating control mode is a chopping control mode, the control unit performs low-power continuous adjustable control according to the current low-continuous heating control mode in combination with the zero-crossing detection signal, including: The control unit controls the driving circuit to operate in a half-cycle working and half-cycle stopping mode in each cycle according to the zero-crossing detection signal.

24. The low-power continuously adjustable heating control method according to claim 22, characterized in that: If the low-continuous heating control mode is a chopping control mode, the control unit performs low-power continuous adjustable control according to the current low-continuous heating control mode in combination with the zero-crossing detection signal, including: The control unit controls the thyristor control circuit to operate in a half-cycle working and half-cycle stopping mode in each cycle according to the zero-crossing detection signal.

25. The low-power continuously adjustable heating control method according to claim 22, characterized in that: If the low continuous heating control mode is a chopping control mode, the control unit performs low power continuous adjustable control according to the current low continuous heating control mode in combination with the zero crossing detection signal, including: The control unit divides each week into a plurality of sub-periods; The control unit controls the driving circuit to operate in an intermittent mode in the plurality of sub-periods according to the zero-crossing detection signal.

26. The low-power continuously adjustable heating control method according to claim 22, characterized in that: If the low continuous heating control mode is a chopping control mode, the control unit performs low power continuous adjustable control according to the current low continuous heating control mode in combination with the zero crossing detection signal, including: The control unit divides each week into a plurality of sub-periods; The control unit controls the thyristor control circuit to operate in an intermittent mode in the plurality of sub-periods according to the zero-crossing detection signal.

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