CN120085056A

CN120085056A - Heater power detection circuit

Info

Publication number: CN120085056A
Application number: CN202510512827.9A
Authority: CN
Inventors: 陈璐; 戴相录; 尹志兴
Original assignee: Shenzhen Hesheng Innovation Technology Co ltd
Current assignee: Shenzhen Hesheng Innovation Technology Co ltd
Priority date: 2025-04-23
Filing date: 2025-04-23
Publication date: 2025-06-03

Abstract

The present application provides a power detection circuit for a heater, the power detection circuit includes a power processing module, a PTC power detection module, a PTC control module and a microcontroller module MCU; wherein the power processing module is used to convert AC power into DC power to power the MCU, the PTC power detection module and the PTC control module; the PTC power detection module is used to collect the effective current and effective voltage of the PTC, and send the effective current and effective voltage to the MCU; the MCU is used to obtain the effective power of the PTC according to the effective current and effective voltage, and send a power adjustment signal to the PTC control module according to the effective power; the PTC control module adjusts the working parameters of the PTC according to the power adjustment signal, so that the effective power is maintained within the normal value range. The power detection circuit of the present application has a simple structure, can effectively and accurately detect the PTC power, and promptly handle abnormal PTC heating events.

Description

Power detection circuit of warm air blower

Technical Field

The application relates to the technical field of power control, in particular to a power detection circuit of a warm air blower.

Background

With the evolution of functions, the real-time detection and tracking of power of a fan heater become a new requirement, and although devices such as a blower and the like at present already have some power detection hardware circuits based on current sampling, most of the devices have higher complexity and higher cost, and the devices cannot adapt to the balance of the fan heater development function between low cost, stability and other comprehensive performances.

Disclosure of Invention

The application provides a power detection circuit of a warm air blower, which is characterized in that the PTC power detection module is used for detecting the effective power of PTC, the MCU is used for determining a power regulation signal according to the effective power, and the PTC control module is used for executing the power regulation signal of the MCU, so that the circuit structure is simple, the PTC power can be effectively and accurately detected, the PTC heating abnormal event can be timely processed, and the stability of the heating effect of a warm air machine is ensured.

In a first aspect, the application provides a power detection circuit of a warm air blower, the warm air blower comprises a positive temperature coefficient thermistor PTC, and the power detection circuit comprises a power supply processing module, a PTC power detection module, a PTC control module and a micro control module MCU; the PTC power control system comprises a power supply processing module, a PTC power detection module, an MCU, a PTC control module, a power regulation signal and a PTC control module, wherein the input end of the power supply processing module is connected between a live wire and a zero wire of an alternating current power grid in a bridging mode, the output end of the power supply processing module is connected to the MCU, the PTC power detection module and the PTC control module respectively, the input end of the PTC power detection module is connected between the live wire and the zero wire in a bridging mode, the input end of the PTC power detection module is connected to the MCU, the PTC power detection module and the PTC control module respectively, the input end of the PTC power detection module is connected between the live wire and the zero wire in a bridging mode, the output end of the PTC control module is connected to the MCU, the input end of the PTC control module is connected with the MCU, the power supply processing module is connected with the live wire respectively, the output end of the PTC power detection module is connected with the live wire respectively, the power processing module is used for converting alternating current into direct current to supply power to the MCU, the PTC power detection module and the PTC control module, the PTC control module supplies power to the PTC control module, the PTC control module is used for collecting effective current and effective voltage of the PTC, the PTC control module is used for sending the effective current and the effective voltage to the MCU, the effective power to the MCU is used for obtaining the effective power of the PTC control module according to the effective power, the effective power to the PTC control module, and the PTC control module to the effective power control module and the PTC control module.

In some embodiments, the PTC power detection module comprises the PTC, a current sampling module, a voltage sampling module and a PTC chip, wherein the PTC is connected between the live wire and the zero wire in a bridging mode, the input end of the current sampling module is connected between the PTC and the zero wire, the output end of the current sampling module is connected to the PTC chip, the input end of the voltage sampling module is connected with the live wire, the output end of the voltage sampling module is connected to the PTC chip, the current sampling module is used for collecting current signals flowing through the PTC and sending the current signals to the PTC chip, the voltage sampling module is used for collecting voltage signals at two ends of the PTC and sending the voltage signals to the PTC chip, and the PTC chip is used for processing the current signals and the voltage signals to obtain effective voltage and effective current and sending the effective voltage and the effective current to the MCU.

In some embodiments, the current sampling module comprises a first resistor, two second resistors and two first capacitors, wherein a first end of the first resistor is an input end of the current sampling module and is connected between the PTC and the zero line, two second ends of the first resistor are respectively connected to the PTC chip through the second resistors, one first capacitor is connected between each second resistor and the PTC chip in parallel to the ground, and the first resistor is used for measuring the current signal passing through the PTC.

In some embodiments, the voltage sampling module comprises six third resistors, a fourth resistor and a second capacitor, wherein the six third resistors are connected in series between the live wire and the ground for dividing voltage, and the first end of the third resistor is connected to the PTC chip through an RC circuit formed by the fourth resistor and the second capacitor.

In some embodiments, two third capacitors are connected in parallel between the power processing module and the PTC chip, and are used for filtering high-frequency noise and low-frequency noise of the ac power grid.

In some embodiments, the PTC control module comprises a relay, the relay comprises a control assembly and a switch assembly, a first end of the switch assembly is connected to the live wire, a second end of the switch assembly is connected to the first end of the PTC, the first end and the second end of the switch assembly are output ends of the PTC control module, the first end of the control assembly is connected to the MCU, the second end of the control assembly is connected to the power supply processing module, and an input end of the PTC control module comprises the first end of the control assembly.

In some embodiments, the control assembly adsorbs the third end of the switch assembly causing the third end to leave the second end of the switch assembly and the PTC stops heating, and the control assembly pops the third end of the switch assembly open causing the third end to connect to the second end of the switch assembly and the PTC begins heating.

In some embodiments, the PTC control module comprises a bidirectional thyristor and a trigger circuit, wherein the input end of the trigger circuit is connected with the MCU, the output end of the trigger circuit is connected with the input end of the bidirectional thyristor, the output end of the bidirectional thyristor is respectively connected with the live wire and the PTC, the trigger circuit is used for generating a trigger signal according to a power regulation signal of the MCU and sending the trigger signal to the bidirectional thyristor, the bidirectional thyristor is conducted after receiving the trigger signal, so that the live wire is communicated with the PTC, the receiving moment of the trigger signal is related to the conduction angle of the bidirectional thyristor, and the conduction angle is positively related to the effective power of the PTC.

In some embodiments, the trigger circuit comprises a fifth resistor, a potentiometer and an optocoupler thyristor driver, wherein a first end of the optocoupler thyristor driver is connected to the MCU through the fifth resistor, a second end of the optocoupler thyristor driver is grounded, the potentiometer is connected in parallel between the first end and the second end of the optocoupler thyristor driver, a third end of the optocoupler thyristor driver is connected with a gate electrode of the bidirectional thyristor, a fourth end of the optocoupler thyristor driver is connected with a first main electrode of the bidirectional thyristor, a first main electrode of the bidirectional thyristor is connected with the fire wire, and a second main electrode of the bidirectional thyristor is connected with a first end of the PTC.

In some embodiments, the output process of the power adjustment signal is that the MCU determines a power abnormality type according to the effective power and a rated power range of the fan heater in a current gear, the MCU calculates a trigger angle and a conduction angle according to the power abnormality type, the trigger angle is a delay time for outputting the power adjustment signal, the conduction angle is related to a conduction angle range of the bidirectional thyristor, the sum of the conduction angle and the trigger angle is 180 degrees, and the MCU delays the trigger angle to output the power adjustment signal after detecting a zero crossing point.

It can be seen that in the embodiment of the application, the fan heater comprises a positive temperature coefficient thermistor PTC, the power detection circuit comprises a power supply processing module, a PTC power detection module, a PTC control module and a micro control module MCU, the input end of the power supply processing module is connected between a live wire and a zero wire of an alternating current power grid in a bridging manner, the output end of the power supply processing module is connected to the MCU, the input end of the PTC power detection module is connected between the live wire and the zero wire, the output end of the PTC power detection module is connected to the MCU, the input end of the PTC control module is connected with the MCU and the power supply processing module, the output end of the PTC control module is connected with the PTC power detection module and the live wire respectively, the power supply processing module is used for converting alternating current into direct current to supply power to the MCU, the PTC power detection module and the PTC control module, the PTC power detection module is used for collecting the effective current and the effective voltage of the PTC, the effective current and the effective voltage are sent to the MCU, the MCU is used for obtaining the effective power of the PTC according to the effective current and the effective voltage, and sending a power adjustment signal to the PTC control module according to the effective power, the PTC control module adjusts the working parameters of the PTC according to the power adjustment signal, and the PTC control module maintains the effective power within a normal numerical range. Therefore, the PTC power detection module is used for detecting the effective power of the PTC, the MCU is used for determining the power regulation signal according to the effective power, and the PTC control module is used for executing the power regulation signal of the MCU, so that the circuit structure is simple, the PTC power can be effectively and accurately detected, the PTC heating abnormal event can be timely processed, and the stability of the heating effect of the warm air machine is ensured.

Drawings

In order to more clearly illustrate the embodiments of the application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a fan heater according to an embodiment of the present application;

fig. 2 is a schematic structural diagram of a micro control module according to an embodiment of the present application;

FIG. 3 is a schematic diagram of the resistance and power curves of the heating element according to the embodiment of the application;

FIG. 4 is a general hardware topology of a power detection circuit according to an embodiment of the present application;

Fig. 5 is a hardware topology diagram of a PTC power detection module according to an embodiment of the present application;

FIG. 6 is a hardware topology diagram of a current sampling module according to an embodiment of the present application;

fig. 7 is a hardware topology diagram of a voltage sampling module according to an embodiment of the present application;

FIG. 8 is a hardware topology of a PTC control module according to an embodiment of the present application;

fig. 9 is a hardware topology diagram of another PTC control module according to an embodiment of the present application;

FIG. 10 is a hardware topology of a trigger circuit according to an embodiment of the present application;

FIG. 11 is a hardware topology diagram of a power processing module according to an embodiment of the present application;

FIG. 12 is a hardware topology diagram of another power processing module according to an embodiment of the present application;

fig. 13 is a schematic flow chart of a power detection method of a fan heater according to an embodiment of the present application;

Fig. 14 is a functional unit block diagram of a power detection device of a fan heater according to an embodiment of the present application.

Detailed Description

In order that those skilled in the art will better understand the present application, a technical solution in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

The terms first, second and the like in the description and in the claims and in the above-described figures are used for distinguishing between different objects and not necessarily for describing a sequential or chronological order. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those listed steps or elements but may include other steps or elements not listed or inherent to such process, method, article, or apparatus.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

In the embodiment of the application, "and/or" describes the association relation of the association objects, which means that three relations can exist. For example, A and/or B may represent three cases, A alone, A and B together, and B alone. Wherein A, B may be singular or plural.

In the embodiment of the present application, the symbol "/" may indicate that the associated object is an or relationship. In addition, the symbol "/" may also denote a divisor, i.e. performing a division operation. For example, A/B may represent A divided by B.

"At least one" or the like in the embodiments of the present application means any combination of these items, including any combination of single item(s) or plural items(s), meaning one or more, and plural means two or more. For example, at least one (one) of a, b or c may represent seven cases a, b, c, a and b, a and c, b and c, a, b and c. Wherein each of a, b, c may be an element or a set comprising one or more elements.

The 'equal' in the embodiment of the application can be used with the greater than the adopted technical scheme, can also be used with the lesser than the adopted technical scheme. When the combination is equal to or greater than the combination, the combination is not less than the combination, and when the combination is equal to or less than the combination, the combination is not greater than the combination.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a fan heater according to an embodiment of the present application, and as shown in fig. 1, a fan heater 10 includes a micro-control module 101, a heating assembly 102 and a fan 103.

The micro-control module 101 is configured to obtain an effective power of the heating assembly 102, and adjust an operating state of the heating assembly 102 and the fan 103 according to the effective power. In particular, referring to fig. 2, fig. 2 is a schematic structural diagram of a micro control module according to an embodiment of the present application, and as shown in fig. 2, the micro control module 101 includes a processor 1011, a memory 1013, a communication interface 1012, and one or more programs 1014. Wherein one or more programs 1014 are stored in the memory 1013 and configured to be executed by the processor 1011, the one or more programs 1014 include instructions for performing any of the steps of one of the power detection method embodiments of the fan heater described below.

The heating assembly 102 comprises a heating body, the heating assembly 102 is used for heating to generate heat, a fan 103 is arranged at one end of the heating body, and the heat generated by the heating body is output from a warm air outlet of the warm air blower 10 through the fan 103. In some embodiments, the heating element is a positive temperature coefficient thermistor (Positive Temperature Coefficient Thermistor, PTC for short). PTC is a semiconductor resistor typically having temperature sensitivity, and its resistance value increases stepwise with an increase in temperature above a certain temperature. The higher the temperature of the heating element, the higher the resistance thereof, the lower the effective power of the heating element, and the lower the temperature of the heating element, the lower the resistance thereof, the higher the effective power of the heating element, as shown in fig. 3, and fig. 3 is a schematic diagram of the resistance and the power curve of the heating element provided by the embodiment of the application.

Therefore, according to the power-resistance property of the PTC, whether the PTC heating is normal can be recognized by the variation of the PTC power.

The fan heater comprises a plurality of heating gears, and each working element in the fan heater in each heating gear corresponds to a rated parameter range and is used for representing the normal working state of each working element. In each heating gear, if the working parameters of the working elements belong to the rated parameter range, the working elements are in a normal working state, and if the working parameters of the working elements do not belong to the rated parameter range, the working elements are in an abnormal working state. For example, the fan heater has five gears, H1-H5, the standard maximum power is 1500W (floating threshold 5%, descending threshold 10%), H1 can be 600W, H5 is 1500W, and the heating power of the heating element is specifically referred to. In FIG. 3, the working temperature of the heating element at the point A is specifically 300 ℃, and after the working temperature is abnormally increased, the power is reduced, such as the point B.

Wherein, the power abnormality includes two cases of abnormal decrease and abnormal increase. And when the effective power is detected to be larger than the rated power range of the current gear, determining that the abnormal condition is abnormal rise.

As is known from the power formula p=u ²/R, the cause of abnormal decrease in the effective power is mainly PTC surface temperature increase, which leads to increase in resistance, and the cause of abnormal increase in the effective power is mainly PTC surface temperature decrease, which leads to decrease in resistance. Further, in the fan heater test link, various risk abnormal events which cause the temperature rise of the PTC surface, such as the toppling or covering of the fan heater, are collected, various risk abnormal events which cause the temperature drop of the PTC surface, such as the fan rotating speed abnormality of the fan heater, the too low ambient temperature which causes the too low wind temperature, the existence of other fan interference, and the like, are collected, a risk abnormal event query list of the fan heater is established by combining the power and other working parameters (such as the fan rotating speed and the ambient temperature) of the fan heater, and when the risk abnormal event occurs later, the risk abnormal event query list is directly checked, so that the corresponding risk abnormal event is accurately and efficiently determined.

However, in the aspect of PTC power detection, although some power detection hardware circuits based on current sampling already exist in devices such as blowers, most of the devices have higher complexity and higher cost, and the devices cannot be adapted to develop the balance between low cost and stability.

In order to solve the technical problems, the application provides a power detection circuit of a warm air blower, which is characterized in that the PTC power detection module is used for detecting the effective power of PTC, the MCU is used for determining a power adjustment signal according to the effective power, and the PTC control module is used for executing the power adjustment signal of the MCU, so that the circuit structure is simple, the PTC power can be effectively and accurately detected, the PTC heating abnormal event can be timely processed, and the stability of the heating effect of a warm air machine is ensured.

Referring to fig. 4, fig. 4 is a general hardware topology diagram of a power detection circuit according to an embodiment of the present application, as shown in fig. 4, the power detection circuit includes a power processing module 1, a PTC power detection module 2, a PTC control module 3, and a micro control module MCU4;

The input end of the power supply processing module 1 is bridged between a live wire ACL and a zero line ACN of an alternating current power grid, and the output end of the power supply processing module 1 is respectively connected with the MCU4, the PTC power detection module 2 and the PTC control module 3;

The power supply processing module 1 is used for converting alternating current into direct current to supply power to the MCU4, the PTC power detection module 2 and the PTC control module 3.

The PTC power detection module 2 is configured to collect an effective current and an effective voltage of the PTC, and send the effective current and the effective voltage to the MCU4.

The MCU4 is configured to obtain the effective power of the PTC according to the effective current and the effective voltage, and send a power adjustment signal to the PTC control module 3 according to the effective power.

Wherein, the PTC control module 3 adjusts the working parameters of the PTC according to the power adjustment signal, so that the effective power is maintained in a normal numerical range.

Referring to fig. 5, fig. 5 is a hardware topology diagram of a PTC power detection module 2 according to an embodiment of the present application, as shown in fig. 5, the PTC power detection module 2 includes the PTC21, a current sampling module 22, a voltage sampling module 23, and a PTC chip 24;

the PTC21 is connected between the live wire ACL and the zero line ACN in a bridging way, the input end of the current sampling module 22 is connected between the PTC21 and the zero line ACN, and the output end of the current sampling module is connected to the PTC chip 24;

The current sampling module 22 is configured to collect a current signal flowing through the PTC and send the current signal to the PTC chip 24. Common current sampling methods include using resistor sampling, current transformer sampling, etc., and the current signal obtained by sampling is typically an analog signal, which is then sent to PTC chip 24 for processing.

The voltage sampling module 23 is configured to collect voltage signals at two ends of the PTC and send the voltage signals to the PTC chip 24. The voltage sampling typically converts the high voltage to a low voltage suitable for chip processing by resistive voltage division or the like, and then sends an analog signal to the PTC chip 24.

The PTC chip 24 is configured to process the current signal and the voltage signal to obtain an effective voltage and an effective current, and send the effective voltage to the MCU4 through a CF interface of the PTC, and send the effective current to the MCU4 through a CFA interface.

It can be seen that, in the present embodiment, the PTC power detection module 2 is mainly used for detecting PTC power, and the core is that the current sampling module 22 and the voltage sampling module 23 respectively collect the voltage signals at the two ends of the PTC, and then the PTC chip 24 processes the current signals and the voltage signals, and sends the obtained effective voltage and effective current to the MCU4 for subsequent power calculation.

Referring to fig. 6, fig. 6 is a hardware topology diagram of a current sampling module according to an embodiment of the present application, as shown in fig. 6, the current sampling module includes a first resistor R1, two second resistors R2, and two first capacitors C1;

The first end of the first resistor R1 is an input end of the current sampling module 22 and is connected between the PTC and the zero line ACN, and the two second ends of the first resistor R1 are respectively connected to a first pin VAP and a second pin VAN of the PTC chip 24 through the second resistor R2, and one first capacitor C1 is connected in parallel between each second resistor R2 and the PTC chip 24 to the ground;

Wherein the first resistor R1 is used to measure the current signal through the PTC.

Specifically, the first resistor R1 is a manganese-copper resistor, the temperature coefficient of the resistance value of the manganese-copper resistor is small, the relatively stable resistance value can be kept under different temperature environments, and the resistance value precision is high and can be accurate to 0.01% or even higher. Based on ohm's law, when the resistance of a manganin resistor is known, the current through it can be accurately calculated by measuring the voltage across it.

In some embodiments, the resistance of the manganese copper resistor is 1mΩ±1%.

The second resistor R2 plays roles of current limiting and impedance matching, protects subsequent circuit elements, and ensures that a current signal input to the PTC chip 24 is stable.

In some embodiments, the resistance of the first resistor R1 is 1kΩ±1%.

The first capacitor C1 is used for filtering high-frequency noise in the current signal, so that the signal input to the PTC chip 24 is purer.

In some embodiments, the capacitance of the first capacitance C1 is 33pF.

Referring to fig. 7, fig. 7 is a hardware topology diagram of a voltage sampling module according to an embodiment of the present application, as shown in fig. 7, the voltage sampling module includes six third resistors R3, a fourth resistor R4, and a second capacitor C2;

The six third resistors R3 are connected in series between the live wire ACL and the ground to divide the voltage, and the first end of the third resistor R3 is connected to the third pin VBP of the PTC chip 24 through an RC circuit formed by the fourth resistor R4 and the second capacitor C2.

The 220V ac voltage is proportionally reduced to a voltage range suitable for the PTC chip 24 input by means of series voltage division, so as to sample the voltage signal.

In some embodiments, the resistance of the third resistor R3 is 470kΩ±1%.

The fourth resistor R4 and the second capacitor C2 form an RC filter circuit, so that noise in the voltage signal is further filtered, and the quality of the sampling signal is improved.

The resistance of the fourth resistor R4 is 1kΩ±1%, and the capacitance of the second capacitor C2 is 100nF.

In some embodiments, referring to fig. 7, two third capacitors C3 are connected in parallel between the power processing module 1 and the fourth pin VDD of the PTC chip 24 for filtering high-frequency and low-frequency noise of the ac power grid.

Referring to fig. 8, fig. 8 is a hardware topology diagram of a PTC control module 3 according to the present application, as shown in fig. 8, the PTC control module 3 includes a relay, the relay includes a control module RL1 and a switch module, a first end 31-1 of the switch module is connected to the live ACL, a second end 31-2 of the switch module is connected to a first end of the PTC (i.e. "PTC-1" in fig. 8), the first end 31-1 and the second end 31-2 of the switch module are output ends of the PTC control module 3, the first end 32-1 of the control module RL1 is connected to the MCU, the second end 32-2 of the control module RL1 is connected to the power processing module 1 (i.e. "+12v" in fig. 8), and an input end of the PTC control module 3 includes the first end 32-1 of the control module RL 1.

The relay generally comprises an iron core, a coil, an armature, a contact reed and the like. When the coil is electrified, a magnetic field is generated in the coil, so that the iron core is magnetized, and the armature is attracted. The action of the armature can drive the contact spring to act, so that the state of the contact is changed, and the on-off control of a circuit is realized. When the coil is powered off, the magnetic field disappears, the armature returns to the initial position under the action of the spring, and the contact is restored. Thus, the relay may act as an automatic switch.

In the implementation of the application, the relay comprises a control component RL1 and a switch component, the switch component is connected between the live wire ACL and the first end of the PTC, and the connection mode of the third end 31-3 of the switch component is controlled by the control component RL1 to realize the opening or closing of the PTC.

In some embodiments, the control assembly RL1 adsorbs the third end 31-3 of the switch assembly causing the third end 31-3 to leave the second end 31-2 of the switch assembly and the PTC stops heating, and the power adjustment signal is an open signal causing the control assembly RL1 to spring the third end 31-3 of the switch assembly open causing the third end 31-3 to connect to the second end 31-2 of the switch assembly and the PTC begins heating.

The MCU calculates effective power according to the effective voltage and the effective current, determines that the power is abnormally increased when the effective power is detected to be larger than the current rated power range, and determines that the power is abnormally decreased when the effective power is detected to be smaller than the current rated power range.

When the power adjustment signal sent by the MCU is an off signal, the power adjustment signal is transmitted to the control component RL1 through the first end 32-1 of the control component RL1, and after the control component RL1 receives the signal, a corresponding electromagnetic force is generated inside the control component RL to adsorb the third end 31-3 of the switch component. As the third terminal 31-3 is attracted away from the second terminal 31-2 of the switching assembly, the electrical circuit connection between the hot line ACL and the PTC is broken, at which point no current passes through the PTC and the PTC stops heating to reduce the PTC temperature and resistance, causing the available power to rise.

When the power adjustment signal sent by the MCU is a closing signal, the electromagnetic force inside the control component RL1 disappears or changes direction after receiving the signal, and the third end 31-3 of the switch component is sprung. The third terminal 31-3 is connected to the second terminal 31-2 of the switching element after having sprung open, thereby enabling the electrical circuit between the fire wire ACL and the PTC. At this time, current may flow from the hot wire ACL through the first and second ends 31-1, 31-2 of the switching element to the PTC, through which the current flows, and thus heating is started to increase the PTC temperature and resistance, so that the effective power is reduced.

The power adjustment signal may take the form of a voltage signal, a pulse signal, or a digitally encoded signal.

The MCU will typically output voltage signals of different levels through its GPIO (general purpose input output) pins to represent power down or up signals. In general, in digital circuits, a high level (e.g., 3.3V or 5V, depending on the supply voltage of the MCU) and a low level (approximately 0V) are used to distinguish between different signal states.

For example, a prescribed high level represents a power up signal and a low level represents a power down signal. When the MCU judges that the PTC power needs to be increased, the corresponding GPIO pin output is set to be high level, and when the PTC power needs to be reduced, the pin output is set to be low level.

The MCU may also output a pulse signal to communicate the power adjustment signal. Parameters such as frequency, duty cycle, etc. of the pulse signal may carry power adjustment information. For example, with Pulse Frequency Modulation (PFM), a higher pulse frequency may represent a power up signal and a lower pulse frequency a power down signal, or with Pulse Width Modulation (PWM), a larger duty cycle corresponds to a power up and a smaller duty cycle corresponds to a power down.

Digitally encoded signals, for some more complex systems, the MCU may transmit the digitally encoded signals over a serial communication interface (e.g., SPI, I2C, etc.). These encoded signals contain detailed power adjustment information, e.g. different power adjustment levels are indicated by different digital codes, e.g. "001" for small amplitude power up "," 010 "for large amplitude power up", "100" for small amplitude power down "and" 110 "for large amplitude power down.

It can be seen that in this embodiment, the relay is used as the control element, and the on-off of the relay assembly is controlled by the instruction sent by the MCU, so as to realize effective control of the PTC heating function.

Referring to fig. 9, fig. 9 is a hardware topology diagram of another PTC control module 3 according to an embodiment of the present application, as shown in fig. 9, the PTC control module 3 includes a triac 31 and a trigger circuit 32;

The input end of the trigger circuit 32 is connected with the MCU, the output end of the trigger circuit 32 is connected with the input end of the bidirectional thyristor 31, and the output end of the bidirectional thyristor 31 is respectively connected with the first ends of the live wire ACL and the PTC;

The trigger circuit 32 is configured to generate a trigger signal according to the power adjustment signal of the MCU, and send the trigger signal to the triac 31, where the triac 31 is turned on after receiving the trigger signal, so that the live wire ACL is communicated with the PTC, the receiving time of the trigger signal correlates with the conduction angle of the triac 31, and the conduction angle is positively correlated with the effective power of the PTC.

The conduction angle of the triac 31 refers to the range of the conduction angle of the triac 31 in one ac cycle. The larger the conduction angle is, the longer the time that the triac 31 is turned on in one cycle is, the higher the effective voltage across the PTC is, and the larger the effective power of the PTC is, whereas the smaller the conduction angle is, the lower the effective voltage across the PTC is, and the smaller the effective power of the PTC is.

Referring to fig. 10, fig. 10 is a hardware topology diagram of a trigger circuit 32 according to an embodiment of the present application, as shown in fig. 10, the trigger circuit 32 includes a fifth resistor R5, a potentiometer 321, and an optocoupler thyristor driver 322;

The first end 10-1 of the optocoupler silicon controlled rectifier driver 322 is connected to the MCU through the fifth resistor R5, the second end 10-2 of the optocoupler silicon controlled rectifier driver 322 is grounded, the potentiometer 321 is connected in parallel between the first end 10-1 and the second end 10-2 of the optocoupler silicon controlled rectifier driver 322, the third end 10-3 of the optocoupler silicon controlled rectifier driver 322 is connected with the gate G of the silicon controlled rectifier 31, the fourth end 10-4 of the optocoupler silicon controlled rectifier driver 322 is connected with the first main electrode T1 of the silicon controlled rectifier 31, the first main electrode T1 of the silicon controlled rectifier 31 is connected with the live wire, and the second main electrode T2 of the silicon controlled rectifier 31 is connected with the first end of the PTC.

The fifth resistor R5 is connected in series with the MCU between the first ends 10-1 of the optocoupler SCR drivers 322 to perform a current limiting function and protect the optocoupler SCR drivers 322.

The potentiometer 321 is connected in parallel with the first end 10-1 and the second end 10-2 of the optocoupler scr driver 322, and the magnitude of the input current flowing into the optocoupler scr driver 322 can be changed by adjusting the resistance value of the potentiometer 321.

The first end 10-1 of the optocoupler driver 322 is connected to the MCU through the fifth resistor R5, receives the power adjustment signal from the MCU, the second end 10-2 is grounded, the third end 10-3 is connected to the gate G of the triac 31, and is used for sending the trigger signal to the triac 31, and the fourth end 10-4 is connected to the first main electrode T1 of the triac 31, so as to form a loop of the trigger signal.

The first main electrode T1 of the triac 31 is connected to the live wire ACL, and the second main electrode T2 is connected to the first end of the PTC as a power input, and supplies the regulated voltage to the PTC.

The bidirectional thyristor 31 can be conducted in both positive and negative half cycles of the ac circuit, and the specific process of adjusting the conduction angle according to the trigger signal is as follows:

The triac 31 has three electrodes, namely a first main electrode T1, a second main electrode T2 and a gate electrode G. The two-phase current-conducting device can be equivalently regarded as two common unidirectional thyristors connected in reverse parallel, and can conduct current in two directions, wherein the conduction needs to meet certain conditions, namely, a proper trigger signal is applied to a gate G, and certain voltage exists between a first main electrode T1 and a second main electrode T2.

In an ac circuit, the supply voltage varies sinusoidally, with a complete ac cycle comprising a positive half cycle and a negative half cycle. When the ac power source is in the positive half cycle, the potential of the first main electrode T1 is assumed to be higher than the potential of the second main electrode T2, and at this time, the forward voltage is applied between the main electrodes of the triac 31, but the triac 31 is not turned on and is in a blocking state.

When a suitable trigger signal is applied to the gate G, this trigger signal will form a trigger current between the gate G and the first main electrode T1. The trigger current changes the semiconductor structure inside the triac 31 to generate a large number of carriers, so that the triac 31 starts to conduct and the PTC can be heated normally.

The moment of arrival of the trigger signal determines the magnitude of the conduction angle. If the trigger signal starts soon in the positive half cycle, the triac 31 will conduct earlier and the conduction angle will be larger, and if the trigger signal starts later, the triac 31 will conduct shorter and the conduction angle will be smaller. Once the triac 31 is turned on, the triac 31 is turned on continuously until the ac voltage crosses zero and the current drops below the holding current, and the triac 31 is turned off even if the trigger signal is lost, as long as the current between the main electrodes is greater than the preset holding current of the triac 31.

The trigger conduction process of the negative half cycle is identical to that of the positive half cycle, except that the direction of the formed current is opposite, and in order to avoid generating reverse current, a diode opposite to the positive current of the PTC can be connected in parallel on the PTC.

The receiving time of the trigger signal by the gate G is related to the time when the MCU sends out the power adjusting signal, the MCU determines the power change condition according to the power abnormality condition, and determines the size of the conduction angle according to the power change condition, so that the power is reduced, the conduction angle is reduced, the power is increased, and the conduction angle is increased.

The MCU is required to detect the zero crossing point of alternating current, and a trigger angle and a conduction angle are calculated according to the target power requirement, wherein the trigger angle is a delay angle of the MCU transmitting power adjusting signals, and the trigger angle plus the conduction angle=180°. The MCU outputs a power adjustment signal according to the trigger angle.

In some embodiments, the output process of the power adjustment signal includes that the MCU determines a power abnormality type according to the effective power and a rated power range of the fan heater in a current gear, calculates a trigger angle and a conduction angle according to the power abnormality type, wherein the trigger angle is a delay time for outputting the power adjustment signal, the conduction angle is related to a conduction angle range of the bidirectional thyristor 31, the sum of the conduction angle and the trigger angle is 180 degrees, and delays the trigger angle to output the power adjustment signal after a zero crossing point is detected.

In some embodiments, the power detection circuit further comprises a zero crossing detection circuit.

Wherein, the power abnormality includes two cases of abnormal decrease and abnormal increase. When the power is abnormally reduced, the power is required to be adjusted to be increased, the conduction angle is increased, the triggering angle is reduced, and when the power is abnormally increased, the power is required to be adjusted to be reduced, the conduction angle is reduced, and the triggering angle is increased.

In the case of full power output, the MCU triggers the triac 31 immediately at the zero crossing of the ac current, the conduction angle=180°, and the PTC attains maximum power. In the case of half power output, the MCU is triggered after being delayed by 90 degrees, the conduction angle=90 degrees, and the PTC power is reduced to 50% of the full power.

After detecting the zero crossing point, the MCU delays the trigger angle and then sends a power adjustment signal, the trigger circuit 32 receives the power adjustment signal and then generates a trigger signal, the trigger signal enables the triac 31 to be turned on, after the triac 31 is turned on, current forms a loop from the live wire ACL, the first main electrode T1, the second main electrode T2, the PTC and the zero line ACN, and the PTC starts to heat. When the current is reduced below the holding current, the triac 31 is automatically turned off and needs to be triggered again to realize periodic conduction control.

It can be seen that in this embodiment, the flexible adjustment of the PTC effective power is realized by the cooperative operation of the MCU, the trigger circuit 32 and the triac 31, which is a simple and effective power adjustment method, and can also improve the timeliness and accuracy of PTC power adjustment.

Referring to fig. 11, fig. 11 is a hardware topology diagram of a power processing module 1 according to an embodiment of the present application, and as shown in fig. 11, the power processing module 1 includes an input protection module 11, a rectifying and filtering module 12, a switching power supply chip 13, a transformer module 14, and an output rectifying and filtering module 15.

Specifically, referring to fig. 12, fig. 12 is a hardware topology diagram of another power processing module 1 according to an embodiment of the present application.

As shown in fig. 12, the input protection module 11 includes a thermal fuse TCO, a fuse F1, a varistor RV1, and a safety capacitor CX1, the thermal fuse TCO is connected in series to a live line ACL input line, the fuse F1 is connected in series to a live line ACL line after the thermal fuse TCO, the varistor RV1 is connected in bridge connection between the live line ACL and the neutral line ACN, and the safety capacitor CX1 is connected in bridge connection between the live line ACL and the neutral line ACN.

The TCO is used for overheat protection, and when the temperature of the circuit is too high, the TCO fuses and cuts off the circuit to play a role of overheat protection. The fuse F1 is used for overcurrent protection, and fuses when the current is excessive, so as to protect a subsequent circuit from large current impact. The piezoresistor RV1 is used for overvoltage protection, when the voltage exceeds the rated value of the transformer, the resistance value is rapidly reduced, and excessive current is introduced into the ground, so that overvoltage protection is realized. The safety capacitor CX1 is used for suppressing electromagnetic interference on the power line.

The rectifying and filtering module 12 includes a sixth resistor R6, three seventh resistors R7, two first diodes D1, two first electrolytic capacitors EC1, an inductor L1, and an eighth resistor R8. The sixth resistor R6 is connected in series on a line before rectification of the live wire ACL, the three seventh resistors R7 are connected in series and connected between the live wire ACL and the zero line ACN in a bridging mode, the two diodes are connected between an alternating current input and a subsequent voltage in a rectifying bridge mode, the two electrolytic capacitors are connected in parallel on a direct current line after rectification, the inductor L1 is connected in series on the direct current line after rectification and filtration, the eighth resistor R8 is connected in parallel with the inductor L1 and connected in a bridging mode between the lines of the two electrolytic capacitors.

The sixth resistor R6 is used for limiting current, and the three seventh resistors R7 are used for dividing voltage so as to protect subsequent elements. The two first diodes D1 constitute a rectifying circuit for converting alternating current into direct current. The first electrolytic capacitor EC1 is used for filtering and smoothing the rectified dc voltage. The inductor L1 is used for suppressing high-frequency interference, and the eighth resistor R8 plays a role in current limiting.

The primary side of the transformer module 14 is connected with the first pin GND of the switching power supply chip 13, and the secondary side is connected with a subsequent rectifying and filtering circuit, so that voltage conversion and electrical isolation are realized.

In some embodiments, the output voltage is +12v.

The output rectifying and filtering module 15 includes a second diode D2, a third diode D3, a second electrolytic capacitor EC2, a third electrolytic capacitor EC3, a fourth capacitor C4, a ninth resistor R9, and two tenth resistors R10. The second diode D2 and the second electrolytic capacitor EC2 are connected in series between the second pin VDD of the switching power supply chip 13 and the secondary side of the transformer T1, the third diode D3 is connected in parallel to the +12V output line, the fourth capacitor C4 is connected in parallel to the +12V output line, the third electrolytic capacitor EC3 is connected in parallel to the +12V output line, the ninth resistor R9 is connected in parallel to the +12V output line, one ends of the two tenth resistors R10 are connected to the primary side of the transformer, and the other ends are connected to the third pin CS of the switching power supply chip 13.

The second diode D2 is used for rectifying the output of the secondary side of the transformer, the third diode D3 plays a role in clamping or protecting, when the secondary side of the transformer T1 has a reverse voltage or transient high voltage peak, the third diode D3 can be conducted to clamp the voltage within a certain range, so that the follow-up elements are prevented from being damaged by the excessive reverse voltage or peak, and the safety and stability of the +12v output circuit are ensured. The second electrolytic capacitor EC2 and the third electrolytic capacitor EC3 are used for filtering. The fourth capacitor C4 is used to filter out high-frequency interference, so that the output voltage is purer, and the ninth resistor R9 is used for current limiting and voltage dividing. The two tenth resistors R10 form a current sampling resistor circuit, the switching power supply chip 13 monitors the voltage drop across the two resistors through the third pin CS, and the voltage drop across the resistors is in a proportional relationship with the current in the circuit. The chip acquires real-time current information of the circuit according to the monitored voltage signal, thereby realizing the functions of overcurrent protection and the like, adjusting parameters such as the on time of the switching tube and the like, and ensuring the stable and safe operation of the power supply system.

The switching power supply chip 13 is connected with peripheral elements such as a resistor, a capacitor, a transformer and the like through a plurality of pins (Drain, VDD, GND, CS in fig. 12) to form a feedback and control loop, and controls the on and off of a switching tube to realize voltage conversion and stable output.

Referring to fig. 13, fig. 13 is a flowchart of a power detection method of a fan heater according to an embodiment of the present application, where the method is applied to an MCU, the fan heater includes the MCU, a PTC power detection module, and a PTC control module, and the method includes steps S131-S133 as follows:

step S131, receiving the effective current and the effective voltage from the PTC power detection module, and obtaining effective power according to the effective current and the effective voltage;

Step S132, determining a power abnormality type according to the effective power and a rated power range of the fan heater in a current gear;

And step S133, generating a power adjustment signal according to the power abnormality type, and sending the power adjustment signal to the PTC control module.

The power adjustment signal is used for indicating the PTC control module to adjust the working parameters of the PTC so that the effective power is maintained in a normal numerical range.

In some embodiments, the determining the power abnormality type according to the effective power and the rated power range of the current gear of the fan heater comprises detecting that the effective power is larger than the rated power range, determining that the power abnormality type is abnormal rising, detecting that the effective power is smaller than the rated power range, and determining that the power abnormality type is abnormal falling.

In some embodiments, the PTC control module comprises a relay disposed between the PTC and the hot line of the ac power grid, the power anomaly type is an abnormal drop, and the power adjustment signal is a power drop signal for indicating that the relay is open such that the PTC stops heating.

In some embodiments, the PTC control module comprises a bidirectional thyristor and a trigger circuit, wherein the bidirectional thyristor is arranged between the PTC and a live wire of an alternating current power grid, the trigger circuit is used for triggering the bidirectional thyristor to conduct, the output process of the power adjustment signal is as follows, a trigger angle and a conduction angle are calculated according to the power abnormality type, the trigger angle is a delay time for outputting the power adjustment signal, the conduction angle is related to the conduction angle range of the bidirectional thyristor, the conduction angle is positively related to the effective power, the sum of the conduction angle and the trigger angle is 180 degrees, and the MCU delays the trigger angle to output the power adjustment signal after detecting a zero crossing point.

According to the embodiment of the application, the fan heater comprises a positive temperature coefficient thermistor PTC, the power detection circuit comprises a power supply processing module, a PTC power detection module, a PTC control module and a micro control module MCU, the PTC power detection module is used for detecting the effective power of the PTC, the MCU is used for determining a power adjustment signal according to the effective power, and the PTC control module is used for executing the power adjustment signal of the MCU, so that the fan heater is simple in circuit structure, can effectively and accurately detect the PTC power and timely process PTC heating abnormal events, and ensures the stability of the heating effect of the fan heater.

The foregoing description of the embodiments of the present application has been presented primarily in terms of a method-side implementation. It will be appreciated that the server, in order to implement the above-described functions, includes corresponding hardware structures and/or software modules that perform the respective functions. Those of skill in the art will readily appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as hardware or combinations of hardware and computer software. Whether a function is implemented as hardware or computer software driven hardware depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

Referring to fig. 14, fig. 14 is a block diagram of a functional unit of a power detection device of a fan heater according to an embodiment of the present application, the power detection device is applied to an MCU, the fan heater 10 includes the MCU, a PTC power detection module, and a PTC control module, and the power detection device 140 includes:

A receiving unit 141 for receiving an effective current and an effective voltage from the PTC power detection module and obtaining an effective power according to the effective current and the effective voltage;

The processing unit 142 determines the power abnormality type according to the effective power and the rated power range of the fan heater in the current gear;

And a transmitting unit 143 configured to generate a power adjustment signal according to the power abnormality type, and transmit the power adjustment signal to the PTC control module, where the power adjustment signal is used to instruct the PTC control module to adjust the PTC operation parameter, so that the effective power is maintained in a normal numerical range.

In some embodiments, the processing unit 142 determines a power abnormality type according to the effective power and a rated power range in a current gear of the fan heater, including detecting that the effective power is greater than the rated power range, determining that the power abnormality type is an abnormal rise, detecting that the effective power is less than the rated power range, and determining that the power abnormality type is an abnormal fall.

It should be understood that, in various embodiments of the present application, the sequence numbers of the foregoing processes do not mean the order of execution, and the order of execution of the processes should be determined by the functions and internal logic thereof, and should not constitute any limitation on the implementation process of the embodiments of the present application.

In the several embodiments provided in the present application, it should be understood that the disclosed method, apparatus and system may be implemented in other manners. For example, the above-described apparatus embodiments are merely illustrative, for example, the division of the units is merely a logical function division, and there may be additional divisions in actual implementation, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.

The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed over a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in the embodiments of the present application may be integrated in one processing unit, or each unit may be physically included separately, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in hardware plus software functional units.

The integrated units implemented in the form of software functional units described above may be stored in a computer readable storage medium. The software functional unit is stored in a storage medium, and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform part of the steps of the method according to the embodiments of the present application. The storage medium includes a USB flash disk, a removable hard disk, a magnetic disk, an optical disk, a volatile memory or a nonvolatile memory. The nonvolatile memory may be a read-only memory (ROM), a Programmable ROM (PROM), an erasable programmable ROM (erasable PROM), an electrically erasable programmable EPROM (EEPROM), or a flash memory. The volatile memory may be random access memory (random access memory, RAM) which acts as external cache memory. By way of example, and not limitation, many forms of random access memory (random access memory, RAM) are available, such as static random access memory (STATIC RAM, SRAM), dynamic Random Access Memory (DRAM), synchronous Dynamic Random Access Memory (SDRAM), double data rate synchronous dynamic random access memory (double DATA RATE SDRAM, DDR SDRAM), enhanced synchronous dynamic random access memory (ENHANCED SDRAM, ESDRAM), synchronous link dynamic random access memory (SYNCHLINK DRAM, SLDRAM), and direct memory bus random access memory (direct rambus RAM, DR RAM), among various media that can store program code.

Although the present application is disclosed above, the present application is not limited thereto. Variations and modifications, including combinations of the different functions and implementation steps, as well as embodiments of the software and hardware, may be readily apparent to those skilled in the art without departing from the spirit and scope of the application.

Claims

1. A power detection circuit for a heater, characterized in that the heater includes a positive temperature coefficient thermistor (PTC), and the power detection circuit includes a power processing module, a PTC power detection module, a PTC control module, and a microcontroller module (MCU);

The input end of the power processing module is connected between the live wire and the neutral wire of the AC power grid, and the output end is connected to the MCU, the PTC power detection module and the PTC control module respectively; the input end of the PTC power detection module is connected between the live wire and the neutral wire, and the output end is connected to the MCU; the input end of the PTC control module is connected to the MCU and the power processing module respectively, and the output end is connected to the PTC power detection module and the live wire respectively;

Among them, the power processing module is used to convert AC power into DC power to power the MCU, the PTC power detection module and the PTC control module; the PTC power detection module is used to collect the effective current and effective voltage of the PTC, and send the effective current and the effective voltage to the MCU; the MCU is used to obtain the effective power of the PTC according to the effective current and the effective voltage, and send a power adjustment signal to the PTC control module according to the effective power; the PTC control module adjusts the working parameters of the PTC according to the power adjustment signal so that the effective power is maintained within a normal value range.

2. The power detection circuit according to claim 1, characterized in that the PTC power detection module includes the PTC, a current sampling module, a voltage sampling module, and a PTC chip;

The PTC is connected across the live wire and the neutral wire; the input end of the current sampling module is connected between the PTC and the neutral wire, and the output end is connected to the PTC chip; the input end of the voltage sampling module is connected to the live wire, and the output end is connected to the PTC chip;

Among them, the current sampling module is used to collect the current signal flowing through the PTC and send the current signal to the PTC chip; the voltage sampling module is used to collect the voltage signal at both ends of the PTC and send the voltage signal to the PTC chip; the PTC chip is used to process the current signal and the voltage signal to obtain the effective voltage and the effective current, and send the effective voltage and the effective current to the MCU.

3. The power detection circuit according to claim 2, characterized in that the current sampling module comprises a first resistor, two second resistors, and two first capacitors;

The first end of the first resistor is the input end of the current sampling module and is connected between the PTC and the neutral line. The two second ends of the first resistor are respectively connected to the PTC chip through the second resistor. A first capacitor is connected in parallel between each second resistor and the PTC chip to the ground.

Wherein, the first resistor is used to measure the current signal passing through the PTC.

4. The power detection circuit according to claim 2, characterized in that the voltage sampling module comprises six third resistors, one fourth resistor, and one second capacitor;

The six third resistors are connected in series between the live wire and the ground for voltage division, and the first end of the third resistor is connected to the PTC chip through an RC circuit formed by the fourth resistor and the second capacitor.

5. The power detection circuit according to claim 2 is characterized in that two third capacitors are connected in parallel between the power processing module and the PTC chip to filter out high-frequency and low-frequency noise of the AC power grid.

6. The power detection circuit according to claim 1 is characterized in that the PTC control module includes a relay, the relay includes a control component and a switch component, the first end of the switch component is connected to the live wire, the second end of the switch component is connected to the first end of the PTC, the first end and the second end of the switch component are the output ends of the PTC control module; the first end of the control component is connected to the MCU, the second end of the control component is connected to the power processing module, and the input end of the PTC control module includes the first end of the control component.

7. The power detection circuit according to claim 6, characterized in that, when the power adjustment signal is a disconnection signal, the control component absorbs the third end of the switch component, causing the third end to leave the second end of the switch component, and the PTC stops heating;

If the power regulation signal is a closed signal, the control component will open the third end of the switch component, so that the third end is connected to the second end of the switch component, and the PTC starts heating.

8. The power detection circuit according to claim 1, characterized in that the PTC control module comprises a bidirectional thyristor and a trigger circuit;

The input end of the trigger circuit is connected to the MCU, the output end of the trigger circuit is connected to the input end of the bidirectional thyristor, and the output end of the bidirectional thyristor is respectively connected to the live wire and the PTC;

Among them, the trigger circuit is used to generate a trigger signal according to the power adjustment signal of the MCU, and send the trigger signal to the bidirectional thyristor. The bidirectional thyristor is turned on after receiving the trigger signal, so that the live wire is connected to the PTC. The reception time of the trigger signal is associated with the conduction angle of the bidirectional thyristor, and the conduction angle is positively correlated with the effective power of the PTC.

9. The power detection circuit according to claim 8, characterized in that the trigger circuit comprises a fifth resistor, a potentiometer, and an optocoupler thyristor driver;

The first end of the optocoupler thyristor driver is connected to the MCU through the fifth resistor, the second end of the optocoupler thyristor driver is grounded, and the potentiometer is connected in parallel between the first and second ends of the optocoupler thyristor driver; the third end of the optocoupler thyristor driver is connected to the gate of the bidirectional thyristor, and the fourth end of the optocoupler thyristor driver is connected to the first main electrode of the bidirectional thyristor; the first main electrode of the bidirectional thyristor is connected to the live wire, and the second main electrode of the bidirectional thyristor is connected to the first end of the PTC.

10. The power detection circuit according to claim 9, characterized in that the output process of the power adjustment signal is as follows:

The MCU determines the power abnormality type according to the effective power and the rated power range of the heater at the current gear position;

The MCU calculates the trigger angle and the conduction angle according to the power abnormality type, the trigger angle is the delay time of outputting the power adjustment signal, and the conduction angle is associated with the conduction angle range of the bidirectional thyristor; the sum of the conduction angle and the trigger angle is 180°;

After the MCU detects the zero-crossing point, it delays the trigger angle and outputs the power adjustment signal.