Output control circuit and method for heating element

Abstract

This solution addresses the problem of interference noise occurring in the power supply due to conventional output adjustment methods, making EMC improvement difficult, and achieves reduced interference noise to the power supply and simplifies EMC improvement. [Solution] This circuit comprises a zero-cross detection module, a microcontroller, a switch control module, a switch module, and a heating element. The zero-cross detection module has a first terminal connected to the zero line, a second terminal connected to the first terminal of the microcontroller, and a third terminal connected to the live line. The second terminal of the microcontroller is connected to the first terminal of the switch control module. The second terminal of the switch control module is connected to the first terminal of the switch module. The second terminal of the switch module is connected to the live line. The microcontroller is configured to transmit a control signal to the switch control module based on a preset temperature signal when it receives a zero-cross signal. The control signal comprises the full waveform, which is an integer required to conduct the switch module within a preset number of operating cycles. The switch control module is configured to receive the control signal and to control the conduction of the switch module and the conduction time of the switch module based on the control signal.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority based on the Chinese patent application filed on May 19, 2023 (application number: 202310575920.5, title: Output control circuit and method for heating element), and the entire disclosure of the prior application is incorporated herein by reference. Technical Field

[0002] The present invention relates to the technical field of electric output, and in particular to an output control circuit and method for a heating element. Background Art

[0003] With the development of economy, people's living standards are improving day by day, and various heating devices are becoming more and more popular and widely used. Heating elements of existing heating devices are mainly classified into luminous heating elements and non-luminous heating elements. Currently, the output of a heating element in a heating device is sometimes adjusted by adjusting the conduction phase angle of a thyristor. However, adjusting the output in this manner causes interference noise in the power supply, which makes EMC improvement difficult. Summary of Invention Problem to be Solved by the Invention

[0004] The present invention solves the problem that the conventional output adjustment method causes interference noise in the power supply and makes EMC improvement difficult, and realizes reduction of interference noise to the power supply and simplification of EMC improvement. Means for Solving the Problem

[0005] According to a first aspect of the present invention, an output control circuit for a heating element is provided, which includes a zero-cross detection module, a microcontroller, a switch control module, a switch module, and a heating element;

[0006] The first terminal of the zero-cross detection module is connected to the zero line, the second terminal of the zero-cross detection module is connected to the first terminal of the microcontroller, the third terminal of the zero-cross detection module is connected to the live line, the fourth terminal of the zero-cross detection module is grounded, the second terminal of the microcontroller is connected to the first terminal of the switch control module, the second end of the switch control module is connected to the first terminal of the switch module, the third terminal of the switch control module is grounded, the second terminal of the switch module is connected to the live line, the third terminal of the switch module is connected to the first terminal of the heating element, and the second terminal of the heating element is connected to the zero line;

[0007] The zero-cross detection module is capable of detecting a voltage signal and is configured to transmit a zero-cross signal to the microcontroller when it detects that the voltage signal exceeds the zero point;

[0008] The microcontroller is configured to transmit a control signal to the switch control module based on a preset temperature signal when it receives the zero-crossing signal, and the control signal comprises a full waveform that is an integer necessary for the switch module to conduct within a preset number of operating cycles;

[0009] The switch control module is provided to receive the control signal and to control the conduction of the switch module and the conduction time of the switch module based on the control signal, thereby controlling the output of the heating element.

[0010] In some embodiments, the first terminal of the voltage stabilization module is connected to a live wire, the second terminal of the voltage stabilization module is connected to the third terminal of the microcontroller, and the voltage stabilization module is configured to supply a stabilized power supply to the microcontroller.

[0011] In some embodiments, the zero-cross detection module includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a diode, a capacitor, and a first NPN transistor;

[0012] The first terminal of the first resistor is connected to the zero line and the second terminal of the heating element, and the second terminal of the first resistor is connected to the first terminal of the second resistor;

[0013] The second terminal of the second resistor is connected to the first terminal of the third resistor, and the second terminal of the third resistor is connected to the first terminal of the fourth resistor, the negative electrode of the diode, and the base electrode of the first NPN transistor;

[0014] The second terminal of the fourth resistor is connected to the positive electrode of the diode, the radiating electrode of the first NPN transistor, and the first terminal of the capacitor;

[0015] The second terminal of the capacitor is connected to the first terminal of the microcontroller;

[0016] The second terminal of the fourth resistor, the radiating electrode of the first NPN transistor, the first terminal of the capacitor, and the positive electrode of the diode are grounded;

[0017] The collecting electrode of the first NPN transistor is connected to the first terminal of the fifth resistor and the first terminal of the sixth resistor;

[0018] The second terminal of the fifth resistor is connected to a live wire, and the second terminal of the sixth resistor is connected to the first terminal of the microcontroller and the second terminal of the capacitor.

[0019] In some embodiments, the switch control module includes a seventh resistor, an eighth resistor, a ninth resistor, and a second NPN transistor;

[0020] A first terminal of the seventh resistor is connected to a second terminal of the microcontroller, and a second terminal of the seventh resistor is connected to a first terminal of the eighth resistor and a base electrode of the second NPN transistor;

[0021] A second terminal of the eighth resistor is connected to an emitter electrode of the second NPN transistor;

[0022] A collector electrode of the second NPN transistor is connected to a first terminal of the ninth resistor;

[0023] A second terminal of the ninth resistor is connected to a first terminal of the switch module;

[0024] The second terminal of the eighth resistor and the emitter electrode of the second NPN transistor are grounded.

[0025] In some embodiments, the switch module comprises a three-terminal triac.

[0026] A second aspect of the present invention proposes an output control method for a heating element applied to a microcontroller,

[0027] the method comprising: when a zero-cross signal transmitted from a zero-cross detection module is received, transmitting a control signal to a switch control module based on a preset temperature signal, thereby enabling the switch control module to receive the control signal; and controlling conduction of a switch module and conduction time of the switch module based on the control signal, thereby controlling an output of the heating element, wherein the control signal comprises all full waveforms that form an integer required for conduction of the switch module within a preset number of operating cycles.

[0028] In some embodiments, the step of transmitting the control signal to the switch control module based on the preset temperature signal is

[0029] A substep involves determining a preset temperature signal based on the heating method entered by the user,

[0030] Based on the preset temperature signal, a substep is performed to determine the number of half-sine waves required for the switch module to conduct within a preset number of operating cycles, which are included in the control signal awaiting transmission.

[0031] The substep includes transmitting the control signal to the switch control module.

[0032] In some embodiments, the operating period is less than or equal to the duration of the preset period, and the operating frequency is higher than the frequency due to the afterimage effect of the human eye.

[0033] In some embodiments, the operating period is the period of a semi-sine wave. [Effects of the Invention]

[0034] In some embodiments, the circuit proposed in the embodiments of the present invention transmits a control signal to a switch control module based on a preset temperature signal when the microcontroller receives a zero-crossing signal provided by a zero-crossing detection module. The control signal comprises all waveforms that are integers necessary for the switch module to conduct within a preset number of operating cycles. The switch control module is configured to receive the control signal and to control the conduction and conduction time of the switch module based on the control signal, thereby controlling the output of the heating element. Since the control signal transmitted from the microcontroller to the switch control module comprises all waveforms that are integers necessary for the switch module to conduct within a preset number of operating cycles, the present invention adjusts the output of the heating element of the heating device by adjusting the number of waveforms necessary for the switch module to conduct within a preset number of operating cycles. This solves the problem of interference noise being generated in the power supply due to conventional output adjustment methods, making EMC improvement difficult, and achieves a reduction in interference noise to the power supply and simplification of EMC improvement. [Brief explanation of the drawing]

[0035] The following drawings, incorporated herein, constitute part of this specification, illustrate embodiments conforming to this utility model, and are used together with the specification to interpret the principles of this utility model.

[0036] To more clearly explain the technical solutions of the embodiments of this invention, the drawings necessary for describing the embodiments are outlined below, and it is clear that those skilled in the art may obtain other drawings by following these drawings without ordinary creative ability.

[0037] [Figure 1] Figure 1 is a schematic diagram of the output control circuit of a heating element according to one embodiment of the present invention.

[0038] [Figure 2] Figure 2 is a schematic diagram of the output control circuit of a heating element according to one embodiment of the present invention.

[0039] [Figure 3] Figure 3 is a schematic diagram of the output control circuit of a heating element according to one embodiment of the present invention. [Modes for carrying out the invention]

[0040] To further clarify the purpose, technical means, and merits of the embodiments of the present invention, the technical means of the embodiments of the present invention will be described clearly and completely below with reference to the drawings of the embodiments, and it goes without saying that the embodiments described are not all embodiments but only a part of the embodiments of the present invention. Any other embodiments that a person skilled in the art could obtain without creative work based on the embodiments of the present invention shall all be included within the scope of the present invention.

[0041] The following disclosure provides various embodiments or examples to achieve different structures of the present invention. In the following embodiments, only specific components and installations are described in order to simplify the disclosure of the present invention. Of course, these embodiments are illustrative only and do not limit the present invention. Furthermore, the present invention may repeat numerical and / or letter notations in different embodiments. Such repetitions are for the purpose of simplification and clarity and do not themselves indicate relationships between the various embodiments and / or installations mentioned.

[0042] Existing heating systems adjust the output of their heating elements by adjusting the conduction phase angle of a thyristor. This adjustment is essentially a control over the load cycle of the heating element during each half-cycle of the AC power supply. While this adjustment method is achieved through chopping of each half-waveform, chopping of the entire waveform causes interference noise to the power supply and makes EMC improvement difficult. To solve the problem of interference noise to the power supply and the difficulty of EMC improvement caused by the output adjustment method of existing heating elements, this invention proposes a method and cycle for controlling the output of the heating element, thereby reducing interference noise to the power supply and simplifying EMC improvement.

[0043] Figure 1 is a schematic diagram of an output control circuit for a heating element according to one embodiment of the present invention. As shown in Figure 1, the output control circuit for a heating element according to the present invention comprises a zero-cross detection module 1, a microcontroller 3, a switch control module 4, a switch module 5, and a heating element 6.

[0044] The first terminal of the zero-cross detection module 1 is connected to the zero line of the commercial power supply, the second terminal of the zero-cross detection module 1 is connected to the first terminal of the microcontroller 3, the third terminal of the zero-cross detection module 1 is connected to the live line of the commercial power supply, and the fourth terminal of the zero-cross detection module 1 is grounded. The commercial power supply may be 220V, 50Hz AC power.

[0045] The second terminal of the microcontroller 3 is connected to the first terminal of the switch control module 4.

[0046] The second terminal of the switch control module 4 is connected to the first terminal of the switch module 5.

[0047] The third terminal of the switch control module 4 is grounded.

[0048] The second terminal of switch module 5 is connected to the live line of the commercial power supply, and the third terminal of switch module 5 is connected to the first terminal of the heating element 6 of the heating device.

[0049] The second terminal of the heating element 6 of the heating device is connected to the zero line of the commercial power supply.

[0050] The zero-cross detection module 1 is designed to detect a rectified voltage signal, in other words, to detect whether the AC commercial power supply voltage exceeds the zero-cross point. If it detects that the AC commercial power supply voltage exceeds the zero point, it sends a zero-cross signal to the microcontroller 3.

[0051] When the microcontroller 3 receives a zero-crossing signal transmitted from the zero-crossing detection module 1, it reads the zero-crossing signal and sends a control signal to the switch control module 4 based on the preset temperature signal.

[0052] This control signal includes all the waveforms necessary for the switch module 5 to conduct within the operating cycle of the preset number, and both the number of presets and the total number of waveforms required for conduction are integers.

[0053] What needs to be explained is that the full waveform required for the continuity of switch module 5 is not a pre-chapped waveform, but the entire waveform, which reduces interference noise to the power supply.

[0054] The switch control module 4 receives control signals transmitted from the microcontroller 3 and controls the conduction of the switch module 5 and the conduction time of the switch module 5 based on the control signals, thereby controlling the output of the heating element 6.

[0055] The explanation needed is that the more waveforms required for the switch module 5 to conduct within the preset operating cycle included in the control signal, the longer the conduction time of the switch module 5 becomes, and consequently, the greater the output of the heating element 6 of the heating device.

[0056] The microcontroller according to this embodiment of the present invention determines a control signal based on a preset temperature signal when it receives a zero-crossing signal transmitted from a zero-crossing detection module. The control signal comprises all waveforms that are integers necessary for the switch module to conduct within a preset number of operating cycles. By transmitting the control signal to the switch control module, the conduction time of the switch module is controlled, and consequently, the output of the heating element is controlled. Because this embodiment of the present invention controls the output of the heating element by the number of integers necessary for the switch module to conduct within a preset number of operating cycles, interference noise to the power supply is reduced, and EMC improvement is made easier.

[0057] We will further describe embodiments of the present invention by combining the circuits shown in Figures 2 and 3.

[0058] As shown in Figure 2, the output control circuit of the heating element according to the present invention further comprises a voltage stabilization module 2. The first terminal of the voltage stabilization module 2 is connected to a live wire; the second terminal of the voltage stabilization module 2 is connected to the third terminal of the microcontroller 3; and the voltage stabilization module 2 is connected to the microcontroller 3 so that a stabilized power supply can be provided to the microcontroller 3.

[0059] In some embodiments, the voltage stabilization module 2 is provided to supply a 5V regulated power supply to the microcontroller 3.

[0060] As shown in Figure 3, the zero-cross detection module 1 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a diode D, a capacitor C, and a first NPN transistor Q1.

[0061] The first terminal of the first resistor R1 is connected to the zero line of the commercial power supply and the second terminal of the heating element 6, and the second terminal of the first resistor R1 is connected to the first terminal of the second resistor R2. The second terminal of the second resistor R2 is connected to the first terminal of the third resistor R3, and the second terminal of the third resistor R3 is connected to the first terminal of the fourth resistor R4, the negative electrode of diode D, and the base electrode of the first NPN transistor Q1. The second terminal of the fourth resistor R4 is connected to the positive electrode of diode D, the radiating electrode of the first NPN transistor Q1, and the first terminal of capacitor C. The second terminal of capacitor C is connected to the first terminal of microcontroller 2. The second terminal of the fourth resistor R4, the radiating electrode of the first NPN transistor Q1, the first terminal of capacitor C, and the positive electrode of diode D are grounded. The collecting electrode of the first NPN transistor Q1 is connected to the first terminal of the fifth resistor R5 and the first terminal of the sixth resistor R6. The second terminal of the fifth resistor R5 is connected to the live power line of the commercial power supply, and the second terminal of the sixth resistor R6 is connected to the first terminal of the microcontroller 3 and the second terminal of the capacitor C.

[0062] The switch control module 4 includes the seventh resistor R7, the eighth resistor R8, the ninth resistor R9, and the second NPN transistor Q2.

[0063] The first terminal of the seventh resistor R7 is connected to the second terminal of the microcontroller 3, and the second terminal of the seventh resistor R7 is connected to the first terminal of the eighth resistor R8 and the base electrode of the second NPN transistor Q2. The second terminal of the eighth resistor R8 is connected to the radiating electrode of the second NPN transistor Q2. The collecting electrode of the second NPN transistor Q2 is connected to the first terminal of the ninth resistor R9. The second terminal of the ninth resistor R9 is connected to the first terminal of the switch module 5. The second terminal of the eighth resistor R8 and the radiating electrode of the second NPN transistor Q2 are grounded.

[0064] The control signal transmitted from the microcontroller 3 effectively controls the conduction of the second NPN transistor Q2, which performs the function of current amplification, thereby achieving control of the switch module 5. Different control signals can control the total number of waveforms required for the switch module 5 to conduct within a preset number of operating cycles. The greater the total number of waveforms required for the switch module 5 to conduct within a preset number of operating cycles, the greater the output of the heating element 6 of the heating device.

[0065] In some embodiments, the switch module 5 includes a three-terminal bidirectional thyristor.

[0066] In some embodiments, the ninth resistor R9 in the switch control module 4 is connected to the control electrode of a three-terminal bidirectional thyristor, the anode of the three-terminal bidirectional thyristor is connected to the live line of the commercial power supply, and the cathode of the three-terminal bidirectional thyristor is connected to the first terminal of the heating element.

[0067] To make it easier to understand, the microcontroller 3 controls the operation of the switch control module 4, the switch control module 4 controls the operation of the three-terminal bidirectional thyristor, and the conduction of the three-terminal bidirectional thyristor controls the operation of the heating element 6.

[0068] It is important to explain that the output control circuit for the heating element according to this invention has a simpler structure and lower cost compared to conventional output control circuits for heating elements.

[0069] Another embodiment of the present invention proposes a method for controlling the electrical output of a heating element using the above circuit. This method is applied to a microcontroller 3 and includes the following steps.

[0070] When a zero-crossing signal is received from the zero-crossing detection module 1, a control signal is sent to the switch control module 4 based on the preset temperature signal. The switch control module 4 receives the control signal and controls the conduction of the switch module 5 and the conduction time of the switch module 5 based on the control signal, thereby controlling the output of the heating element 6. The control signal includes all waveforms that are integers necessary for the conduction of the switch module within a preset number of operating cycles.

[0071] The heating element output control method proposed in the embodiment of this invention involves a microcontroller receiving a zero-crossing signal from a zero-crossing detection module and transmitting a control signal to a switch control module based on a preset temperature signal. The control signal comprises the entire waveform, which is an integer necessary for the switch module to conduct within a preset number of operating cycles. The switch control module is configured to receive the control signal and control the conduction and conduction time of the switch module based on the control signal, thereby controlling the output of the heating element. Since the control signal transmitted from the microcontroller to the switch control module comprises the entire waveform, which is an integer necessary for the switch module to conduct within a preset number of operating cycles, this method adjusts the output of the heating element of the heating device by adjusting the number of waveforms necessary for the switch module to conduct within a preset number of operating cycles. This solves the problem of interference noise being generated in the power supply due to conventional output adjustment methods, making EMC improvement difficult, and achieves a reduction in interference noise to the power supply and simplification of EMC improvement.

[0072] In some embodiments, the zero-cross detection module 1 detects the voltage signal of the commercial power supply, and when it detects that the voltage signal of the commercial power supply has reached a zero-cross point, the zero-cross detection module generates a zero-cross signal and transmits this zero-cross signal to the microcontroller 3.

[0073] Microcontroller 3 receives this zero-crossing signal and sends a control signal to switch control module 4 based on the preset temperature signal. It should be explained that this preset temperature signal may be determined by the heating method entered by the user, or in other words, by the temperature set by the user in microcontroller 3. Of course, this preset temperature signal may also be automatically set by microcontroller 3 depending on the ambient temperature both indoors and outdoors, and the temperature of the copper tubes in the indoor evaporator.

[0074] We will describe an embodiment of the present invention as an example in which a preset temperature signal is determined by the heating method input by the user.

[0075] In some embodiments, after the step in which a preset temperature signal is determined by a heating method input by the user, the method includes the following steps.

[0076] Based on the preset temperature signal, the number of half-sine waves required for the switch module to conduct within a preset number of operating cycles, which is included in the control signal awaiting transmission, is determined, and this control signal is transmitted to the switch control module.

[0077] To understand this, the entire waveform can be either a half-sine wave or a half-cosine wave. Using the example that the entire waveform can be a half-sine wave, once a preset temperature signal is determined, we can determine, based on this preset temperature signal, the number of half-sine waves required for the switch module to conduct within a preset number of operating cycles.

[0078] In some embodiments, this operating period is the period of a semi-sine wave.

[0079] The microcontroller transmits a predetermined control signal to the switch control module; in other words, it transmits a predetermined half-sine wave to the switch control module that is the integer required for the switch module to conduct within a preset number of operating cycles. Based on this control signal, the switch control module controls the conduction and conduction time of the switch module, and consequently controls the output of the heating element.

[0080] In some embodiments, as shown in Table 1, this preset number of operating cycles can be three. Each operating cycle is a half-sine wave period. The heating method input by the user is to select a signal to input the heating method. Selecting a signal for the heating method may be to select a signal according to different heating adjustment points.

[0081] [Table 1]

[0082] The explanation needed is that the microcontroller selects a signal based on the heating control point input by the user and then determines the control signal.

[0083] In some embodiments, the signal selection terms based on the user-inputted heating control point may be a first control point, a second control point, and a third control point. The first control point may be the lowest control point. The third control point may be the highest control point. To understand this, the number of signals selected based on the user-inputted heating control point is the same as the number of preset operating cycles.

[0084] In some embodiments, when the selection term of the signal based on the heating adjustment point input by the user is the first adjustment point, the control signal is one half-sine wave required to conduct the switch module within each of the three operating cycles, in other words, one half-sine wave conducts out of each of the three half-sine waves.

[0085] As shown in Table 1, the switch module conducts during the first operating cycle and does not conduct during the remaining two operating cycles within each of its three operating cycles. When the switch module conducts one semisine wave within the three operating cycles, the heat output of the heating element may be reduced to one-third of its maximum heat output.

[0086] If the signal selection term based on the heating adjustment point input by the user is the second adjustment point, the control signal consists of two half-sine waves necessary for the switch module to conduct within each of the three operating cycles; in other words, two of the three half-sine waves conduct.

[0087] As shown in Table 1, the switch module conducts during the first two operating cycles within each of its three operating cycles, and does not conduct during the remaining operating cycle. When the switch module conducts two semisine waves within the three operating cycles, the heat output of the heating element may be reduced to 2 / 3 of its maximum heat output.

[0088] If the signal selection term based on the heating adjustment point input by the user is the third adjustment point, the control signal consists of three half-sine waves necessary for the switch module to conduct within each of the three operating cycles; in other words, three of the three half-sine waves conduct within each of the three half-sine waves.

[0089] The explanation needed is that the switch module maintains a continuous conduction state within three operating cycles. When the switch module conducts three semisine waves within three operating cycles, the heat output of the heating element may reach its maximum heat output.

[0090] In some embodiments, the selection terms of the signal based on the heating control point input by the user may be a first control point, a second control point, a third control point, and a fourth control point. The first control point may be the lowest control point. The fourth control point may be the highest control point.

[0091] As shown in Table 2, there are four preset operating cycles, and each operating cycle corresponds to the period of a half-sine wave.

[0092] [Table 2]

[0093] In some embodiments, when the selection term of the signal based on the heating adjustment point input by the user is the first adjustment point, the control signal is one half-sine wave required to conduct the switch module within each of the four operating cycles, in other words, one half-sine wave conducts out of each of the four half-sine waves.

[0094] The explanation needed is that the switch module conducts during the first of its four operating cycles, but not during the remaining three. When the switch module conducts one semi-sine wave within its four operating cycles, the heat output of the heating element may be reduced to one-quarter of its maximum heat output.

[0095] If the signal selection term based on the heating adjustment point input by the user is the second adjustment point, the control signal consists of two half-sine waves required for the switch module to conduct within each of the four operating cycles; in other words, two half-sine waves conduct within each of the four half-sine waves.

[0096] The explanation needed is that the switch module conducts during the first two operating cycles of each of its four operating cycles, and does not conduct during the remaining two. When the switch module conducts two semisine waves within its four operating cycles, the heat output of the heating element may be halved to half of its maximum heat output.

[0097] If the signal selection term based on the heating control point input by the user is the third control point, the control signal consists of three half-sine waves necessary for the switch module to conduct within each of the four operating cycles; in other words, three of the four half-sine waves conduct.

[0098] The explanation needed is that the switch module conducts during the first three operating cycles within each of its four operating cycles, and does not conduct during the remaining operating cycle. When the switch module conducts three semisine waves within its four operating cycles, the heat output of the heating element may be 3 / 4 of its maximum heat output.

[0099] If the signal selection term based on the heating control point input by the user is the fourth control point, the control signal consists of four half-sine waves necessary for the switch module to conduct within each of the four operating cycles; in other words, four of the four half-sine waves conduct within each of the four half-sine waves.

[0100] The explanation needed is that the switch module maintains a continuous conductive state within its four operating cycles. When the switch module conducts four semisine waves within its four operating cycles, the heat output of the heating element may reach its maximum heat output.

[0101] In some embodiments, the operating period is less than or equal to the duration of the preset period, and the operating frequency of the heating element is higher than the frequency due to the afterimage effect of the human eye.

[0102] The explanation needed is that, when the heating element of a heating device is a visible light heating element, setting the duration of each operating cycle to less than or equal to the duration of a preset cycle eliminates the flickering of the visible light heating element, thereby improving the user experience.

[0103] In some embodiments, the frequency due to the afterimage effect of the human eye is generally 24 Hz. When the operating cycle can be set to 40 ms or less, the operating frequency becomes 25 Hz or higher, which is higher than the frequency due to the afterimage effect of the human eye. As a result, the flashing of the visible light heating element is not visible to the human eye, improving the user experience.

[0104] It should be understood that the terms used in this text are intended solely to describe specific embodiments and are not intended to be limiting. Unless otherwise explicitly stated in the context, the singular forms “one,” “a,” and “the aforementioned” used in this text have a plural meaning. The terms “include,” “contain,” “include,” and “equip” have the meaning of inclusion and indicate the presence of the described features, steps, operations, parts, and / or components, but do not exclude having or adding one or more other features, steps, operations, parts, components, and / or combinations thereof. The steps, procedures, and operations of the methods described in this text are not to be construed as having to be performed in a specific order described or illustrated unless the order of execution is explicitly stated.

[0105] The above description represents only specific embodiments of the present invention, sufficient for those skilled in the art to understand or implement it. Various modifications to these embodiments are obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to these embodiments shown herein, but rather conforms to the broadest scope that is consistent with the principles and novel features of this application.

Claims

1. It comprises a zero-cross detection module, a microcontroller, a switch control module, a switch module, and a heating element. The first terminal of the zero-cross detection module is connected to the zero line, the second terminal of the zero-cross detection module is connected to the first terminal of the microcontroller, the third terminal of the zero-cross detection module is connected to the live line, the fourth terminal of the zero-cross detection module is grounded, the second terminal of the microcontroller is connected to the first terminal of the switch control module, the second end of the switch control module is connected to the first terminal of the switch module, the third terminal of the switch control module is grounded, the second terminal of the switch module is connected to the live line, the third terminal of the switch module is connected to the first terminal of the heating element, and the second terminal of the heating element is connected to the zero line; The zero-cross detection module is capable of detecting a voltage signal and is configured to transmit a zero-cross signal to the microcontroller when it detects that the voltage signal exceeds the zero point; The microcontroller is provided so that when it receives the zero-crossing signal, it can transmit a control signal to the switch control module based on a preset temperature signal. The control signal comprises all waveforms that are integers necessary for the switch module to conduct within a preset number of operating cycles. The switch control module is provided to receive the control signal and to control the conduction of the switch module and the conduction time of the switch module based on the control signal, thereby controlling the output of the heating element. An output control circuit for a heating element, characterized by the following features.

2. It also includes a voltage stabilization module; The first terminal of the voltage stabilization module is connected to a live wire, the second terminal of the voltage stabilization module is connected to the third terminal of the microcontroller, and the voltage stabilization module is provided so that a stabilized power supply can be supplied to the microcontroller. The circuit according to feature 1.

3. The zero-cross detection module comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a diode, a capacitor, and a first NPN transistor; The first terminal of the first resistor is connected to the zero line and the second terminal of the heating element, and the second terminal of the first resistor is connected to the first terminal of the second resistor; The second terminal of the second resistor is connected to the first terminal of the third resistor, and the second terminal of the third resistor is connected to the first terminal of the fourth resistor, the negative electrode of the diode, and the base electrode of the first NPN transistor; The second terminal of the fourth resistor is connected to the positive electrode of the diode, the radiating electrode of the first NPN transistor, and the first terminal of the capacitor; The second terminal of the capacitor is connected to the first terminal of the microcontroller; The second terminal of the fourth resistor, the radiating electrode of the first NPN transistor, the first terminal of the capacitor, and the positive electrode of the diode are grounded; The collecting electrode of the first NPN transistor is connected to the first terminal of the fifth resistor and the first terminal of the sixth resistor; The second terminal of the fifth resistor is connected to a live wire, and the second terminal of the sixth resistor is connected to the first terminal of the microcontroller and the second terminal of the capacitor. The circuit according to claim 1 or 2.

4. The aforementioned switch control module has a seventh resistor, an eighth resistor, a ninth resistor, and a second NPN transistor; The first terminal of the seventh resistor is connected to the second terminal of the microcontroller, and the second terminal of the seventh resistor is connected to the first terminal of the eighth resistor and the base electrode of the second NPN transistor; The second terminal of the eighth resistor is connected to the radiating electrode of the second NPN transistor; The collector electrode of the second NPN transistor is connected to the first terminal of the ninth resistor; The second terminal of the aforementioned ninth resistor is connected to the first terminal of the switch module; The second terminal of the eighth resistor and the radiating electrode of the second NPN transistor are grounded. The circuit according to any one of claims 1-3.

5. The circuit according to any one of claims 1 to 4, characterized in that the switch module includes a three-terminal bidirectional thyristor.

6. A method for controlling the electrical output of a heating element using a circuit according to any one of claims 1 to 5, applicable to a microcontroller, The steps include: when a zero-crossing signal is received from the zero-crossing detection module, a control signal is sent to the switch control module based on a preset temperature signal, thereby enabling the switch control module to receive the control signal; This includes the step of controlling the conduction of the switch module and the conduction time of the switch module based on the control signal, and thereby controlling the output of the heating element. The control signal comprises all waveforms that are integers necessary for the switch module to conduct within a preset number of operating cycles. A method characterized by the following:

7. The step of sending a control signal to the switch control module based on a preset temperature signal, A substep involves determining a preset temperature signal based on the heating method entered by the user, Based on the preset temperature signal, a substep is performed to determine the number of half-sine waves required for the switch module to conduct within a preset number of operating cycles, which are included in the control signal awaiting transmission. The substep includes transmitting the control signal to the switch control module, The method according to feature 6.

8. The operating period is less than or equal to the duration of the preset period, and the operating frequency is higher than the frequency due to the afterimage effect of the human eye. The method according to 6 or 7, characterized by the features described above.

9. The method according to any one of claims 6-8, characterized in that the operating period is the period of a semi-sine wave.

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