Novel heating element control circuit and kettle

Abstract

The utility model discloses a novel heating element control circuit and a kettle. The control circuit comprises a switching power supply circuit, a microcontroller, an input voltage detection circuit, an output current detection circuit, an input zero-crossing signal detection circuit, an output zero-crossing signal detection circuit, a silicon controlled rectifier power output circuit and a heating element. Under wide voltage of a global power grid and input voltage with different frequencies, according to feedback of output active power, output current, input voltage and the like, each time of output can be dynamically adjusted in real time, safe, stable and efficient operation of a heating element under constant power is confirmed, safety problems are prevented, and performance requirements of equipment are met.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kettle technology field, specifically to a novel heating element control circuit and kettle. BACKGROUND

[0002] The kettle generally adopts the heating element to carry out the electric heating to the water body in the kettle. However, due to the difference of input power and frequency in each country, the kettle often does not have the global universality. In order to solve this problem, the kettle on the current market designs a mechanism: by adding the resistance to the power input end to detect the input voltage and zero-crossing signal, and then regulating the on and off period of the silicon controlled rectifier, so as to achieve the purpose of adjusting the power. Although this method can realize the basic function, it has significant defects and may cause a series of problems.

[0003] Specifically, the scheme does not configure the detection circuit at the output end, cannot monitor and feedback the key parameters such as active power, voltage value and effective current value of the output in real time, cannot realize the closed-loop control, causes the deviation between the output waveform, power, current value etc. set at the control end and the actual output value, sometimes even completely inconsistent. Especially when the power grid is disturbed or the performance of the silicon controlled rectifier is changed due to heating and other factors, the micro processing unit may incorrectly adjust the on-off of the silicon controlled rectifier to adjust the power, and the output end has no immediate feedback mechanism to correct this error. Such cases not only seriously affect the heating effect of the kettle, but also may cause the overheating damage of the heating tube, circuit board and even the shell and other components due to the long-term abnormal work, more seriously, may cause the fire and other safety hazards. These accidents are not uncommon in the market, highlighting the shortcomings of the existing scheme in stability and safety. Therefore, it is particularly important to optimize and upgrade the control circuit of the kettle, especially to add the monitoring and feedback mechanism at the output end. CONTENT OF THE UTILITY MODEL

[0004] In order to overcome the problem that the control circuit of the kettle in the prior art cannot realize the closed-loop control due to the absence of the immediate feedback mechanism at the output end, the utility model provides a novel heating element control circuit and kettle.

[0005] The technical scheme of the utility model is as follows:

[0006] The utility model provides a novel heating element control circuit, including switching power supply circuit, microcontroller, input voltage detection circuit, output current detection circuit, input zero -crossing signal detection circuit, output zero -crossing signal detection circuit, thyristor power output circuit and heating element, switching power supply circuit is connected with input power supply, microcontroller and thyristor power output circuit respectively, microcontroller still is connected with input voltage detection circuit, input voltage detection circuit, output zero -crossing signal detection circuit and thyristor power output circuit respectively, output current detection circuit is connected with input voltage detection circuit, output current detection circuit, thyristor power output circuit and heating element respectively, input voltage detection circuit, input voltage detection circuit and heating element still are connected with input power supply.

[0007] As a preferred scheme of the utility model, the input voltage detection circuit comprises resistance R24, resistance R25, resistance R26, resistance R27, resistance R28, resistance R29, resistance R30, capacitor C2, metering chip U3, one end of the resistance R24 is connected with the fire line end of the input power supply, the other end of the resistance R24 is connected with one end of the resistance R30, one end of the capacitor C2 and the 4th pin of the metering chip U3 after passing through the resistance R25, the resistance R26, the resistance R27, the resistance R28 and the resistance R29, the other end of the resistance R30 and the other end of the capacitor C2 are grounded, the 6th, 7th and 8th pins of the metering chip U3 are connected with the microcontroller.

[0008] As a preferred scheme of the utility model, the output current detection circuit comprises sampling resistance R3, resistance R6, resistance R9, capacitor C5, capacitor C6, capacitor C9, electrolytic capacitor EC1, the input end of the sampling resistance R3 is connected with one end of the resistance R6 and the output end of the thyristor power output circuit respectively, the output end of the sampling resistance R3 is connected with one end of the resistance R9, one end of the output zero -crossing signal detection circuit and one end of the heating element respectively, the other end of the resistance R6 is connected with one end of the capacitor C5 and the 2nd pin of the metering chip U3 respectively, the other end of the resistance R9 is connected with one end of the capacitor C9 and the 3rd pin of the metering chip U3 respectively, the other end of the capacitor C5 is connected with the other end of the capacitor C9, one end of the capacitor C6 and the negative pole of the electrolytic capacitor EC1 respectively, the other end of the capacitor C6 is connected with the positive pole of the electrolytic capacitor EC1, the 1st pin of the metering chip U3 and power voltage respectively.

[0009] As a preferred scheme of the utility model, the input zero-crossing signal detection circuit includes resistance R11, resistance R16, diode D3, diode D4, one end of resistance R11 is connected with the fire line end of input power supply, the other end of resistance R11 is connected with the negative pole of diode D3, the positive pole of diode D4 and microcontroller respectively after passing through resistance R16, the positive pole of diode D3 is grounded, and the negative pole of diode D4 is connected with power voltage.

[0010] As a preferred scheme of the utility model, the output zero-crossing signal detection circuit includes resistance R36, resistance R37, resistance R38, resistance R39, diode D8, diode D9, one end of resistance R36 is connected with one end of resistance R38 and the output end of output current detection circuit respectively, the other end of resistance R36 is connected with the positive pole of diode D8, the negative pole of diode D9 and microcontroller respectively after passing through resistance R37, the negative pole of diode D8 is connected with power voltage, the positive pole of diode D9 is grounded, and the other end of resistance R38 is connected with the fire line end of input power supply after passing through resistance R39.

[0011] As a preferred scheme of the utility model, the silicon controlled power output circuit includes bidirectional thyristor Q3, capacitor C8, resistance R34, resistance R35, resistance R40, the first end of bidirectional thyristor Q3 is connected with one end of capacitor C8, one end of resistance R40 and the output end of switching power supply circuit respectively, the second end of bidirectional thyristor Q3 is connected with the other end of resistance R40 and microcontroller respectively after passing through resistance R34, the second end of bidirectional thyristor Q3 is connected with one end of resistance R35 and the input end of output current detection circuit respectively, and the other end of capacitor C8 is connected with the other end of resistance R35.

[0012] As a preferred scheme of the utility model, the switching power supply circuit includes pressure sensitive resistance MOV1, inductance L2, electrolytic capacitor EC3, electrolytic capacitor EC4 and switching power supply chip U1, one end of pressure sensitive resistance MOV1, the negative pole of electrolytic capacitor EC3, the negative pole of electrolytic capacitor EC4, the 1st, 2nd, 3rd and 4th pins of switching power supply chip U1 are all connected with the zero line end of input power supply, the other end of pressure sensitive resistance MOV1, one end of inductance L2 and the positive pole of electrolytic capacitor EC4 are all connected with the fire line end of input power supply, and the other end of inductance L2 is connected with the positive pole of electrolytic capacitor EC3 and the 5th, 6th, 7th and 8th pins of switching power supply chip U1 respectively.

[0013] As a preferred scheme of the utility model, it further includes temperature measurement circuit, and the temperature measurement circuit is connected with microcontroller.

[0014] As a preferred scheme of the utility model, the temperature measuring circuit includes a thermistor R10 for detecting the temperature of the silicon controlled rectifier and a thermistor R13 for detecting the temperature of the hot water, and the thermistor R10 and the thermistor R13 are connected with the microcontroller.

[0015] In the second aspect, the utility model provides a hot water kettle, including the kettle body, be provided with the novel heating element control circuit of any scheme above on the kettle body.

[0016] Compared with the prior art, the utility model has the beneficial effects that:

[0017] 1, the novel heating element control circuit provided by the utility model can dynamically adjust each output in real time according to the feedback of output active power, output current, input voltage and the like under the wide voltage, different frequency input voltage of global power grid, confirms that the heating element is safely, stably and efficiently operated under constant power, prevents safety problems and meets the performance requirements of equipment.

[0018] 2, by setting input voltage detection circuit, output current detection circuit, input zero-crossing signal detection circuit, output zero-crossing signal detection circuit, temperature measuring circuit, the input voltage of power grid, effective output active power, effective output current value, input and output zero-crossing signal, silicon controlled rectifier temperature and water temperature are monitored simultaneously, the input power supply and the silicon controlled rectifier power output circuit can be detected and prompted whether there is a fault, and be closed in time, so as to avoid burning and possible safety problems such as fire;

[0019] 3, by adopting double zero-crossing circuit (input zero-crossing signal detection circuit, output zero-crossing signal detection circuit), the output result of the next trigger can be accurately detected. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical scheme in the embodiment of the utility model, the drawings needed to be used in the embodiment or prior art description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the utility model, and those skilled in the art can obtain other drawings according to these drawings without creating labor.

[0021] Figure 1 It is the structure block diagram of the novel heating element control circuit in an embodiment of the utility model;

[0022] Figure 2 It is the circuit principle diagram of the novel heating element control circuit in an embodiment of the utility model;

[0023] Figure 3The conducting waveform diagram before the power output end is adjusted in an embodiment of the utility model;

[0024] Figure 4 The conducting waveform diagram after the power output end is adjusted in an embodiment of the utility model;

[0025] Figure 5 The output waveform diagram of the silicon controlled power output circuit in an embodiment of the utility model. DETAILED DESCRIPTION

[0026] In order to make the technical problems, technical schemes and beneficial effects to be solved in the utility model more clear and obvious, the utility model is further described in detail below by combining with the drawings and embodiments. It should be noted that similar signs and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the following drawings. Meanwhile, it is declared that the following described embodiments are only used for explaining the utility model and do not limit the utility model.

[0027] It should be noted that the terms such as "mounting", "setting", "connecting", "fixing" and the like should be understood broadly, for example, can be fixed connection, can also be detachable connection, or integrated; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the communication inside two elements or the interaction relationship of two elements, unless otherwise clearly limited. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly placed when the product of the application is used, or the orientation or positional relationship commonly understood by the person skilled in the art, or the orientation or positional relationship commonly placed when the product of the application is used, which is only for the convenience of describing the application and simplifying the description, and cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, therefore, it cannot be understood as limiting the application.

[0028] Please refer to Figure 1The embodiment provides a novel heating element control circuit, which comprises a switching power supply circuit 1, a microcontroller 2, an input voltage detection circuit 3, an output current detection circuit 4, an input zero-crossing signal detection circuit 5, an output zero-crossing signal detection circuit 6, a thyristor power output circuit 7 and a heating element 8, the switching power supply circuit 1 is connected with an input power supply, the microcontroller 2 and the thyristor power output circuit 7 respectively, the microcontroller 2 is also connected with the input voltage detection circuit 3, the input voltage detection circuit 3, the output zero-crossing signal detection circuit 6 and the thyristor power output circuit 7 respectively, the output current detection circuit 4 is connected with the input voltage detection circuit 3, the output current detection circuit 4, the thyristor power output circuit 7 and the heating element 8 respectively, and the input voltage detection circuit 3, the input voltage detection circuit 3 and the heating element 8 are also connected with the input power supply.

[0029] The switching power supply circuit 1 is used for converting alternating input voltage of the input power supply (such as mains) into smooth direct current output voltage (i.e. power supply voltage).

[0030] The input voltage detection circuit 3 is used for detecting voltage of the input power supply in real time and outputting to the microcontroller 2, so that the microcontroller 2 can control the thyristor power output circuit 7 to adjust output power when the input power supply suddenly changes or voltage fluctuates, thereby preventing the heating element 8 from being damaged.

[0031] The output current detection circuit 4 is used for detecting working current in real time and outputting to the input voltage detection circuit 3 to calculate active power, and then outputting the calculated active power to the microcontroller 2, so that the microcontroller 2 adjusts output power of the thyristor power output circuit 7 according to the current feedback active power, and the heating element 8 can maintain constant heating power under different power supply voltages and frequencies.

[0032] The input zero-crossing signal detection circuit 5 is used for detecting input zero-crossing signal of the input power supply in real time and outputting to the microcontroller 2, and the output zero-crossing signal detection circuit 6 is used for detecting output zero-crossing signal after power supply output in real time and outputting to the microcontroller 2; the microcontroller 2 can detect and prompt whether the power supply input and the thyristor power output circuit 7 exist faults through the input zero-crossing signal and the output zero-crossing signal, and timely closes.

[0033] The thyristor power output circuit 7 is used for adjusting output power size through chopping or wave loss according to the control instruction of the microcontroller 2, so that the heating element 8 maintains constant active power output.

[0034] Please refer to Figure 2 In the embodiment, the microcontroller 2 uses an MCU chip U1, so as to save cost and facilitate circuit expansion.

[0035] Please refer to Figure 2In the embodiment, the input voltage detection circuit 3 comprises resistors R24, R25, R26, R27, R28, R29, R30, capacitor C2, and metering chip U3. One end of the resistor R24 is connected to the live terminal of the input power supply. The other end of the resistor R24 is connected to one end of the resistor R30, one end of the capacitor C2, and the fourth pin of the metering chip U3 through the resistors R25, R26, R27, and R28. The other end of the resistor R30 and the other end of the capacitor C2 are grounded. The sixth, seventh, and eighth pins of the metering chip U3 are connected to the thirteenth, fourteenth, and fifteenth pins of the MCU chip U1, respectively. The voltage of the input power supply is sampled through the resistors R24, R25, R26, R27, R28, R29, and R30 and the fourth pin V2P of the metering chip U3. The MCU chip U1 can obtain the active output power of the thyristor power output circuit 7 by detecting the signal of the sixth pin CF of the metering chip U3. The MCU chip U1 can obtain the output voltage and effective current value of the thyristor power output circuit 7 by setting the eighth pin SEL of the metering chip U3 and then alternately detecting the signal of the seventh pin CF1 of the metering chip U3.

[0036] Please refer to Figure 2 In the embodiment, the output current detection circuit 4 comprises sampling resistor R3, resistor R6, resistor R9, capacitor C5, capacitor C6, capacitor C9, and electrolytic capacitor EC1. The input end of the sampling resistor R3 is connected to one end of the resistor R6 and the output end of the thyristor power output circuit 7, respectively. The output end of the sampling resistor R3 is connected to one end of the resistor R9, one end of the output zero-crossing signal detection circuit 6, and one end of the heating element 8, respectively. The other end of the resistor R6 is connected to one end of the capacitor C5 and the second pin of the metering chip U3, respectively. The other end of the resistor R9 is connected to one end of the capacitor C9 and the third pin of the metering chip U3, respectively. The other end of the capacitor C5 is connected to the other end of the capacitor C9, one end of the capacitor C6, and the negative electrode of the electrolytic capacitor EC1, respectively. The other end of the capacitor C6 is connected to the positive electrode of the electrolytic capacitor EC1, the first pin of the metering chip U3, and the power supply voltage, respectively. The sampling resistor R3 is made of manganese copper resistor or constantan resistor with good thermal stability, hard texture, and accurate resistance.

[0037] The output current detection circuit 4 described above adopts differential signal sampling to eliminate interference and ensure the accuracy of output current sampling. The input end of the sampling resistor R3 is filtered by the resistor R6 and the capacitor C5 and then enters the 2nd pin V1P of the metering chip U3; the output end of the sampling resistor R3 is filtered by the resistor R9 and the capacitor C9 and then enters the 3rd pin V1N of the metering chip U3; the two paths form differential input, have strong anti-interference performance, and can accurately measure the current value of the power supply output end, so as to accurately calculate the output active power, the accuracy is less than or equal to 0.2%, and real-time monitoring of the output power is realized.

[0038] Specifically, the voltage, current and power values of the metering chip U3 before leaving the factory are measured, and then the measurement instrument is calibrated and the deviation value is modified, and the active power meets the accuracy requirements of the 50 / 60Hz IEC 687 / 1036 standard. The power accuracy can reach ±0.2%; the voltage value accuracy can reach ±0.5%, and this is taken as the reference object to adjust the power. The measured voltage value and current value are processed by the DSP inside the metering chip U3, and then the power value is calculated and output to the MCU chip U1.

[0039] The following is the principle of adjusting the power of the heating element 8 with a power of 100V, 1000W:

[0040] When the heating element 8 is used at a voltage of 100V, 50Hz, its power is 1000W. When the input power supply voltage becomes 220V, 50Hz, at this time, the initial on-time is calculated according to the voltage value and current value measured by the metering chip U3; then the active power is adjusted according to the active power feedback by the metering chip U3.

[0041] At this time, the voltage is 220V, 50Hz, and the on-time needs to be adjusted to adjust the power. Assuming that the voltage is 220V, 50Hz, the on-frequency f is hertz.

[0042] f = (P1 / P2) x 50Hz = (U12 / U22) x 50Hz = (100 2 / 220 2 ) x 50Hz = 10.33Hz. At this time, because the input power supply voltage is 220V, 50Hz, 10.33 cycles are selected to be turned on in 50 cycles of 1s, and the on waveform is as shown in Figure 3 .

[0043] Take 5 waveforms as a group, turn on one of the 5 waveforms, and so on, but turn on the last 1 waveform of the 10th group in the period of 0.33%, and the on waveform is as shown in Figure 3 .

[0044] When the above preliminary calculation power appears deviation, then need to adjust in the next cycle, can carry on many times gradually adjusts the power, such as above 100V 1000W heating element 8 is used in 220V 50Hz power grid, target power is 1000W, the active power returned by metering chip U3 is 960W, deviation 40W, at this time, adjust, increase the on time, calculate as follows, the adjusted on frequency is f1.

[0045] f1 / 10.33=1000 / 960W;f1=10.76Hz;then the adjusted on waveform is as follows Figure 4

[0046] Please refer to Figure 2 In the embodiment, the input zero-crossing signal detection circuit 5 includes resistors R11, R16, diodes D3, D4, one end of the resistor R11 is connected with the firewire end of the input power supply, the other end of the resistor R11 is connected with the negative electrode of the diode D3, the positive electrode of the diode D4 and the 8th pin of the MCU chip U1 through the resistor R16, the positive electrode of the diode D3 is grounded, and the negative electrode of the diode D4 is connected with the power supply voltage. The input zero-crossing signal detection circuit 5 is simple in structure, realizes real-time detection of the input zero-crossing signal of the input power supply, and outputs to the MCU chip U1, so that the MCU chip U1 can detect and prompt whether there is a fault in the input power supply in real time, and the safety performance of the circuit is improved.

[0047] Please refer to Figure 2 In the embodiment, the output zero-crossing signal detection circuit 6 includes resistors R36, R37, R38, R39, diodes D8, D9, one end of the resistor R36 is connected with one end of the resistor R38 and the output end of the output current detection circuit 4, the other end of the resistor R36 is connected with the positive electrode of the diode D8, the negative electrode of the diode D9 and the 11th pin of the MCU chip U1 through the resistor R37, the negative electrode of the diode D8 is connected with the power supply voltage, the positive electrode of the diode D9 is grounded, the other end of the resistor R38 is connected with the firewire end of the input power supply through the resistor R39. The output zero-crossing signal detection circuit 6 is simple in structure, realizes real-time detection of the output zero-crossing signal after the output of the power supply, and outputs to the MCU chip U1, so that the MCU chip U1 can detect and prompt whether there is a fault in the silicon-controlled power output circuit 7 in real time, and is closed in time, and the safety performance of the circuit is improved.

[0048] Please refer to Figure 2 ​In the embodiment, the silicon controlled power output circuit 7 includes a triac Q3, a capacitor C8, a resistor R34, a resistor R35, a resistor R40, the first end of the triac Q3 is connected with one end of the capacitor C8, one end of the resistor R40 and the output end of the switching power supply circuit 1, the second end of the triac Q3 is connected with the other end of the resistor R40 and the MCU chip U1 through the resistor R34, the second end of the triac Q3 is connected with one end of the resistor R35 and the input end of the output current detection circuit 4, the other end of the capacitor C8 is connected with the other end of the resistor R35. The silicon controlled power output circuit 7 is used to control the heating element 8 to keep constant active power output, the triac Q3 is used, and the resistor R35 and the capacitor C8 are used for wave absorption to prevent the triac Q3 from being controlled to conduct due to the instantaneous voltage change at both ends of the triac Q3, thereby ensuring safe output, and the output waveform is as shown in Figure 5

[0049] Please refer to Figure 2 In the embodiment, the switching power supply circuit 1 includes a voltage-dependent resistor MOV1, an inductor L2, an electrolytic capacitor EC3, an electrolytic capacitor EC4 and a switching power supply chip U1, one end of the voltage-dependent resistor MOV1, the negative electrode of the electrolytic capacitor EC3, the negative electrode of the electrolytic capacitor EC4 and the 1st, 2nd, 3rd and 4th pins of the switching power supply chip U1 are connected with the zero line end of the input power supply, the other end of the voltage-dependent resistor MOV1, one end of the inductor L2 and the positive electrode of the electrolytic capacitor EC4 are connected with the fire line end of the input power supply, the other end of the inductor L2 is connected with the positive electrode of the electrolytic capacitor EC3 and the 5th, 6th, 7th and 8th pins of the switching power supply chip U1. The switching power supply circuit 1 can effectively prevent the circuit board from being damaged due to lightning by setting the voltage-dependent resistor MOV1 at the power supply input end, and can effectively prevent the EMC problem by setting the inductor L2, the electrolytic capacitor EC3 and the electrolytic capacitor EC4 to form a filter circuit.

[0050] Please refer to Figure 1 In one embodiment, the novel heating element control circuit further includes a temperature measurement circuit 9 connected with the microcontroller 2. The temperature measurement circuit 9 can be used to detect the temperature of the kettle and the temperature of the triac Q3 in the silicon controlled power output circuit 7. The temperature measurement circuit 9 can realize NTC fault prompting and closing the heating and triac Q3 overheat fault closing output and prompting, thereby safely and stably triggering the triac Q3 output.

[0051] Please refer to Figure 2 ​The temperature measuring circuit 9 comprises a thermistor R10 for detecting the temperature of the bidirectional thyristor Q3 and a thermistor R13 for detecting the temperature of the hot water, one end of the thermistor R10 and one end of the thermistor R13 are connected with the 2nd pin and the 3rd pin of the MCU chip U1 respectively, and the other end of the thermistor R10 and the other end of the thermistor R13 are grounded. The temperature of the bidirectional thyristor is detected by the thermistor R10, so as to prevent the occurrence of the overheat no trigger direct conduction fault of the bidirectional thyristor Q3, thereby avoiding the possible safety problems such as burning and fire. The hot water is heated and the water temperature is controlled according to the temperature value of the thermistor R13.

[0052] Specifically, the circuit detects the temperature of the bidirectional thyristor Q3 by the thermistor R10 before heating, and if the temperature exceeds the preset temperature limit value, the heating is forcibly turned on and a fault is reported. If there is still power before the heating is turned on or after the heating is turned off, the hot water will report a fault to the user.

[0053] In summary, the novel heating element control circuit can adapt to various different power supply voltages and frequencies, and can keep the heating power constant under different voltages by using the triggering conduction of the thyristor under the condition that the rated power of the heating element 8 is determined.

[0054] In one embodiment, the utility model provides a kettle, including the kettle body, be provided with the novel heating element control circuit of any one embodiment on the kettle body. The kettle can adapt to various different power supply voltages and frequencies by the novel heating element control circuit, and can keep the heating power constant under different voltages by using the triggering conduction of the thyristor under the condition that the rated power of the heating element 8 is determined.

[0055] It should be noted that the novel heating element control circuit of the utility model is not limited to be used in the kettle, and can also be used in other products.

[0056] It should be understood that the above description can be improved or changed by those skilled in the art, and all these improvements and changes shall fall within the protection scope of the appended claims of the utility model.

[0057] The utility model discloses has been described exemplarily above in combination with the drawing, obviously the implementation of the utility model patent is not limited by above-mentioned mode, as long as the various improvements of the method concept and technical scheme of the utility model patent are adopted, or the concept and technical scheme of the utility model patent are directly applied to other occasions without improvement, all are within the protection scope of the utility model.

Claims

1. A novel heating element control circuit, characterized by, The switch power supply circuit, the microcontroller, the input voltage detection circuit, the output current detection circuit, the input zero-crossing signal detection circuit, the output zero-crossing signal detection circuit, the thyristor power output circuit and the heating element are connected with the input power supply, the microcontroller and the thyristor power output circuit respectively.

2. The novel heat-generating element control circuit according to claim 1, characterized by The input voltage detection circuit includes resistors R24, R25, R26, R27, R28, R29, R30, a capacitor C2 and a metering chip U3. One end of the resistor R24 is connected with the live wire end of the input power supply. The other end of the resistor R24 is connected with one end of the resistor R30, one end of the capacitor C2 and the fourth pin of the metering chip U3 through the resistors R25, R26, R27, R28 and R29 respectively. The other end of the resistor R30 and the other end of the capacitor C2 are grounded. The sixth, seventh and eighth pins of the metering chip U3 are connected with the microcontroller.

3. A novel heating element control circuit according to claim 2, characterised in that, The output current detection circuit includes a sampling resistor R3, resistors R6, R9, capacitors C5, C6 and C9, and an electrolytic capacitor EC1. The input end of the sampling resistor R3 is connected with one end of the resistor R6 and the output end of the thyristor power output circuit respectively. The output end of the sampling resistor R3 is connected with one end of the resistor R9, one end of the output zero-crossing signal detection circuit and one end of the heating element respectively. The other end of the resistor R6 is connected with one end of the capacitor C5 and the second pin of the metering chip U3 respectively. The other end of the resistor R9 is connected with one end of the capacitor C9 and the third pin of the metering chip U3 respectively. The other end of the capacitor C5 is connected with the other end of the capacitor C9, one end of the capacitor C6 and the negative electrode of the electrolytic capacitor EC1 respectively. The other end of the capacitor C6 is connected with the positive electrode of the electrolytic capacitor EC1, the first pin of the metering chip U3 and the power supply voltage respectively.

4. The novel heat generating element control circuit according to claim 1, characterized by, The input zero-crossing signal detection circuit includes resistors R11 and R16, diodes D3 and D4. One end of the resistor R11 is connected with the live wire end of the input power supply. The other end of the resistor R11 is connected with the negative electrode of the diode D3, the positive electrode of the diode D4 and the microcontroller through the resistor R16 respectively. The positive electrode of the diode D3 is grounded. The negative electrode of the diode D4 is connected with the power supply voltage.

5. The novel heat generating element control circuit according to claim 1, characterized by, The output zero signal detection circuit comprises resistors R36, R37, R38, R39, diodes D8, D9, one end of the resistor R36 is connected with one end of the resistor R38 and the output end of the output current detection circuit respectively, the other end of the resistor R36 is connected with the positive electrode of the diode D8, the negative electrode of the diode D9 and the microcontroller through the resistor R37, the negative electrode of the diode D8 is connected with the power voltage, the positive electrode of the diode D9 is grounded, and the other end of the resistor R38 is connected with the fire end of the input power supply through the resistor R39.

6. The novel heat-generating element control circuit according to claim 1, characterized by The silicon controlled power output circuit comprises a bidirectional thyristor Q3, a capacitor C8, resistors R34, R35, R40, the first end of the bidirectional thyristor Q3 is connected with one end of the capacitor C8, one end of the resistor R40 and the output end of the switching power supply circuit respectively, the second end of the bidirectional thyristor Q3 is connected with the other end of the resistor R40 and the microcontroller through the resistor R34, the second end of the bidirectional thyristor Q3 is connected with one end of the resistor R35 and the input end of the output current detection circuit respectively, and the other end of the capacitor C8 is connected with the other end of the resistor R35.

7. The novel heat-generating element control circuit according to claim 1, characterized by The switching power supply circuit comprises a pressure sensitive resistor MOV1, an inductor L2, electrolytic capacitors EC3, EC4 and a switching power supply chip U1, one end of the pressure sensitive resistor MOV1, the negative electrode of the electrolytic capacitor EC3, the negative electrode of the electrolytic capacitor EC4 and the 1st, 2nd, 3rd and 4th pins of the switching power supply chip U1 are connected with the zero end of the input power supply, the other end of the pressure sensitive resistor MOV1, one end of the inductor L2 and the positive electrode of the electrolytic capacitor EC4 are connected with the fire end of the input power supply, and the other end of the inductor L2 is connected with the positive electrode of the electrolytic capacitor EC3 and the 5th, 6th, 7th and 8th pins of the switching power supply chip U1 respectively.

8. The novel heat-generating element control circuit according to claim 1, characterized by The temperature measurement circuit is further connected with the microcontroller.

9. A novel heat-generating element control circuit according to claim 8, characterized by The temperature measurement circuit comprises a thermistor R10 for detecting the temperature of the silicon controlled and a thermistor R13 for detecting the water temperature of the kettle, and the thermistor R10 and the thermistor R13 are connected with the microcontroller.

10. A hot water kettle comprising a kettle body, characterised in that, The kettle body is provided with the novel heating element control circuit according to any one of claims 1-9.

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