阅读说明：本技术 一种低压电热膜电采暖一拖n交互控制的控制方法 (Control method for one-to-N interactive control of low-voltage electric heating film electric heating ) 是由 向玮 吴世忠 方军 于 2021-10-21 设计创作，主要内容包括：本发明提供一种低压电热膜电采暖一拖N交互控制的控制方法,包括：采用1个变压器为N个采暖单元中的电热膜发热系统供电；通过N个温控器监测N个采暖单元的温度来判断对应的电热膜发热系统是否需要工作；对需要工作的电热膜发热系统通过功率判断选择进行全部工作或进行交互工作。本发明通过交互控制,在同一时刻只控制需要工作的电热膜发热系统中的部分电热膜发热系统进行工作,变压器额定功率只需要大于在工作的这部分电热膜发热系统的总功率即可,而不需要大于所有N个电热膜发热系统的总功率,从而能够减小变压器的体积、重量,变压器的利用率大幅提升,采暖系统需配置的电网容量大幅度减小。(The invention provides a control method for one-to-N interactive control of low-voltage electric heating film electric heating, which comprises the following steps: 1 transformer is adopted to supply power for the electrothermal film heating systems in the N heating units; the temperature of the N heating units is monitored through the N temperature controllers to judge whether the corresponding electrothermal film heating system needs to work or not; and selecting to carry out all work or interactive work on the electrothermal film heating system needing to work through power judgment. According to the invention, through interactive control, only part of the electrothermal film heating systems in the electrothermal film heating systems needing to work are controlled to work at the same time, the rated power of the transformer only needs to be larger than the total power of the part of the electrothermal film heating systems needing to work, and does not need to be larger than the total power of all N electrothermal film heating systems, so that the size and the weight of the transformer can be reduced, the utilization rate of the transformer is greatly improved, and the capacity of a power grid which needs to be configured in the heating system is greatly reduced.)

1. A control method for one-to-N interactive control of low-voltage electric heating film electric heating is characterized by comprising the following steps:

1 transformer is adopted to supply power for N electrothermal film heating systems in N heating units; wherein N is not less than 2 and is an integer;

the temperature of the N heating units is monitored through the N temperature controllers to judge whether the corresponding electrothermal film heating system needs to work or not;

and selecting to carry out all work or interactive work on the electrothermal film heating system needing to work through power judgment.

2. The control method for the low-voltage electrothermal film electric heating one-to-N interactive control according to claim 1, wherein the method for supplying power to the electrothermal film heating systems in the N heating units by using 1 transformer comprises the following steps:

employing a transformer having 1 primary winding and at least N secondary windings;

connecting the primary winding of the transformer with a power supply to form an input circuit; the N secondary windings of the transformer are respectively and correspondingly connected with N electrothermal film heating systems of N heating units to form N output branches;

and the power supply supplies power to the electrothermal film heating systems in the N heating units sequentially through the input circuit and the N output branches.

3. The control method for the low-voltage electrothermal film electric heating one-to-N interactive control according to claim 2, further comprising:

and performing on-off control on the input circuit.

4. The control method for the low-voltage electrothermal film electric heating one-to-N interactive control according to claim 3, wherein the method for controlling the on/off of the input circuit comprises:

the method comprises the following steps that a primary control circuit is adopted, the action end of the primary control circuit is connected into an input circuit, and a control unit is adopted to control the control end of the primary control circuit;

the control of the power supply of the control unit is realized by adopting N temperature controllers:

(1) when at least one of the N temperature controllers is in a power-on state, the temperature controllers supply power to the control unit, the control unit controls the control end of the primary control circuit to close the action end of the primary control circuit, and the input circuit is conducted;

(2) when the N temperature controllers are all in the shutdown state, the temperature controllers power off the control unit, and the control unit has no input to the control end of the primary control circuit, so that the action end of the primary control circuit is disconnected, and the input circuit is disconnected.

5. The control method of low-voltage electrothermal film electric heating one-drive-N interactive control according to claim 4, wherein the method for determining whether the corresponding electrothermal film heating system needs to work by monitoring the temperature of N heating units through N temperature controllers comprises:

presetting temperature thresholds in the N temperature controllers;

when the temperature of the heating unit monitored by the temperature controller does not reach a preset temperature threshold value, an electric heating film heating system corresponding to the temperature controller needs to work; when the temperature of the temperature controller monitoring heating unit reaches the preset temperature threshold value, the electric heating film heating system corresponding to the temperature controller does not need to work.

6. The control method for the low-voltage electric heating film electric heating one-driving-N interactive control according to claim 2, wherein the method for selecting to perform the whole work or the interactive work on the electric heating film heating system needing to work through power judgment comprises the following steps:

when M electrothermal film heating systems need to work, N is more than or equal to M and is more than or equal to 1, and M is an integer, the rated power P1 of the transformer is compared with the total power P2 of the M electrothermal film heating systems when the M electrothermal film heating systems work:

when P1 is more than or equal to P2, controlling all output branches corresponding to the M electrothermal film heating systems to be conducted;

when P1 < P2, the corresponding output branches of the M electrothermal film heating systems are controlled to be alternately conducted.

7. The control method for low-voltage electrothermal film electric heating one-drive-N interactive control according to claim 6, wherein the method for controlling the output branches corresponding to the M electrothermal film heating systems to be conducted completely or alternatively comprises:

a secondary control circuit is adopted, the secondary control circuit comprises N control branches, action ends of the N control branches are respectively and correspondingly connected to the N output branches, and a control unit is adopted to control the control ends of the N control branches;

when the temperature controller judges that the corresponding electrothermal film heating system needs to work, a control signal is input to the control unit, and the control unit compares the rated power P1 of the transformer with the total power P2 of the M electrothermal film heating systems during working:

when P1 is more than or equal to P2, the control unit provides control signals to the control ends of the control branches corresponding to the M electrothermal film heating systems, so that the action ends of the corresponding control branches are closed, and the output branches corresponding to the M electrothermal film heating systems are controlled to be completely conducted;

when P1 < P2, the control unit provides control signals to the control ends of the control branches corresponding to the M electrothermal film heating systems alternately, so that the action ends of the corresponding control branches are closed alternately, and the output branches corresponding to the M electrothermal film heating systems are controlled to be switched on alternately.

8. The control method for the electric heating one-drive-N interactive control of the low-voltage electric heating film heating system according to claim 6, wherein the control of the alternate conduction of the output branches corresponding to the M electric heating film heating systems is that:

presetting a working period in a control unit, and dividing M electrothermal film heating systems into a first part and a second part;

in a working period, controlling all output branches corresponding to the first part of electric heating film heating system to be switched on, and controlling all output branches corresponding to the second part of electric heating film heating system to be switched off; in the next working period, controlling all output branches corresponding to the second part of electric heating film heating system to be switched on, and controlling all output branches corresponding to the first part of electric heating film heating system to be switched off; therefore, the output branches corresponding to the first part and the second part of the M electrothermal film heating systems are controlled to be alternately conducted in a working period.

9. The control method for the low-voltage electrothermal film electric heating one-to-N interactive control according to claim 1, further comprising:

and carrying out overheat protection on the electrothermal film heating system.

10. The control method for the low-voltage electrothermal film electric heating one-to-N interactive control according to claim 1, further comprising:

and performing overheat protection and overcurrent protection on the transformer.

Technical Field

The invention relates to the technical field of electricity, in particular to a control method for one-to-N interactive control of low-voltage electric heating film electric heating.

Background

The low-voltage electric heating film system consists of a transformer, a temperature controller and an electric heating film heating system, wherein the transformer converts the voltage of a power grid into isolated safe voltage and then supplies power to the electric heating film heating system, and the temperature controller is responsible for temperature acquisition and temperature control of a heating unit (a room or a heating area). Generally, a transformer and a temperature controller are required to be arranged in one heating unit (room or heating area), if the number of the heating units (room or heating area) provided with a heating system is large, the number of the matched transformers is also large, the construction difficulty is high, and the cost is high; the number of transformers can be reduced by adopting a one-to-N control circuit, but the transformer capacity of N heating units (rooms or heating areas) is integrated on one large-capacity transformer, so that the transformer is large in size, heavy in weight, inconvenient to construct and high in cost, and the power consumption of the transformer is increased; how to solve the defect that the volume and the weight of a transformer in a low-voltage electric heating film one-to-N control circuit are overlarge is a problem which is always considered by a person skilled in the art.

Disclosure of Invention

The invention aims to provide a control method for one-to-N interactive control of low-voltage electric heating film electric heating, and aims to solve the problems that a transformer in a low-voltage electric heating film one-to-N control circuit is overlarge in size and weight, low in utilization rate of the transformer and the like.

The invention provides a control method for one-to-N interactive control of low-voltage electric heating film electric heating, which is characterized by comprising the following steps of:

1 transformer is adopted to supply power for the electrothermal film heating systems in the N heating units; wherein N is not less than 2 and is an integer;

the temperature of the N heating units is monitored through the N temperature controllers to judge whether the corresponding electrothermal film heating system needs to work or not;

and selecting to carry out all work or interactive work on the electrothermal film heating system needing to work through power judgment.

Further, the method for supplying power to the electrothermal film heating systems in the N heating units by adopting 1 transformer comprises the following steps:

employing a transformer having 1 primary winding and at least N secondary windings;

connecting the primary winding of the transformer with a power supply to form an input circuit; the N secondary windings of the transformer are respectively and correspondingly connected with the electrothermal film heating systems of the N heating units to form N output branches;

and the power supply supplies power to the electrothermal film heating systems in the N heating units sequentially through the input circuit and the N output branches.

Further, the control method for one-to-N interactive control of low-voltage electric heating film electric heating further comprises the following steps:

and performing on-off control on the input circuit.

Further, the method for controlling the on/off of the input circuit comprises the following steps:

the method comprises the following steps that a primary control circuit is adopted, the action end of the primary control circuit is connected into an input circuit, and a control unit is adopted to control the control end of the primary control circuit;

the control of the power supply of the control unit is realized by adopting N temperature controllers:

(1) when at least one of the N temperature controllers is in a power-on state, the temperature controllers supply power to the control unit, the control unit controls the control end of the primary control circuit to close the action end of the primary control circuit, and the input circuit is conducted;

(2) when the N temperature controllers are all in the shutdown state, the temperature controllers power off the control unit, and the control unit has no input to the control end of the primary control circuit, so that the action end of the primary control circuit is disconnected, and the input circuit is disconnected.

Further, the method for monitoring the indoor temperature of the N heating units through the N temperature controllers to judge whether the corresponding electrothermal film heating system needs to work or not comprises the following steps:

presetting temperature thresholds in the N temperature controllers;

when the temperature of the heating unit monitored by the temperature controller does not reach a preset temperature threshold value, an electric heating film heating system corresponding to the temperature controller needs to work; when the temperature of the temperature controller monitoring heating unit reaches the preset temperature threshold value, the electric heating film heating system corresponding to the temperature controller does not need to work.

Further, the method for selecting to perform all work or perform interactive work on the electrothermal film heating system needing to work through power judgment comprises the following steps:

when M electrothermal film heating systems need to work, N is more than or equal to M and is more than or equal to 1, and M is an integer, the rated power P1 of the transformer is compared with the total power P2 of the M electrothermal film heating systems when the M electrothermal film heating systems work:

when P1 is more than or equal to P2, controlling all output branches corresponding to the M electrothermal film heating systems to be conducted;

when P1 < P2, the corresponding output branches of the M electrothermal film heating systems are controlled to be alternately conducted.

Further, the method for controlling the output branches corresponding to the M electrothermal film heating systems to be fully conducted or alternatively conducted includes:

a secondary control circuit is adopted, the secondary control circuit comprises N control branches, action ends of the N control branches are respectively and correspondingly connected to the N output branches, and a control unit is adopted to control the control ends of the N control branches;

when the temperature controller judges that the corresponding electrothermal film heating system needs to work, a control signal is input to the control unit, and the control unit compares the rated power P1 of the transformer with the total power P2 of the M electrothermal film heating systems during working:

when P1 is more than or equal to P2, the control unit provides control signals to the control ends of the control branches corresponding to the M electrothermal film heating systems, so that the action ends of the corresponding control branches are closed, and the output branches corresponding to the M electrothermal film heating systems are controlled to be completely conducted;

when P1 < P2, the control unit provides control signals to the control ends of the control branches corresponding to the M electrothermal film heating systems alternately, so that the action ends of the corresponding control branches are closed alternately, and the output branches corresponding to the M electrothermal film heating systems are controlled to be switched on alternately.

Further, controlling the output branches corresponding to the M electrothermal film heating systems to be alternately switched on means:

presetting a working period in a control unit, and dividing M electrothermal film heating systems into a first part and a second part;

in a working period, controlling all output branches corresponding to the first part of electric heating film heating system to be switched on, and controlling all output branches corresponding to the second part of electric heating film heating system to be switched off; in the next working period, controlling all output branches corresponding to the second part of electric heating film heating system to be switched on, and controlling all output branches corresponding to the first part of electric heating film heating system to be switched off; therefore, the output branches corresponding to the electrothermal film heating systems of the first part and the second part in the M electrothermal film heating systems are controlled to be alternately conducted in a working period.

Further, the control method for the electric heating one-drive-N interactive control of the low-voltage electric heating film heating system further comprises the following steps:

and carrying out overheat protection on the electrothermal film heating system.

Further, the control method for the electric heating one-drive-N interactive control of the low-voltage electric heating film heating system further comprises the following steps:

and performing overheat protection and overcurrent protection on the transformer.

In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:

the temperature of N heating units is monitored by N temperature controllers to judge whether the corresponding electrothermal film heating systems in the heating units need to work or not, and when the total power of the electrothermal film systems needing to work is less than the rated power of a transformer, all the electrothermal film heating systems needing to work are worked; when the total power of the electrothermal film heating system needing to work exceeds the rated power of the transformer, the electrothermal film heating system needing to work is interactively controlled, namely, only the electrothermal film heating systems of part of heating units in the heating units needing to work are controlled to work at the same moment, the rated power of the transformer only needs to be larger than the total power of the electrothermal film heating systems in the part needing to work, and does not need to be larger than the total power of the electrothermal film heating systems of all N heating units, so that the size and the weight of the transformer can be reduced, the utilization rate of the transformer is greatly improved, and the capacity of a power grid which needs to be configured in the heating system is greatly reduced.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a flowchart of a control method for low-voltage electric heating film electric heating one-to-N interactive control according to an embodiment of the present invention.

Fig. 2 is an electrical schematic diagram of a control method for low-voltage electric heating film electric heating one-to-N interactive control according to an embodiment of the invention.

Fig. 3 is a partial electrical wiring diagram of the thermostat to the control unit according to the embodiment of the present invention.

Fig. 4 is an electrical wiring diagram of the single chip microcomputer U2 according to the embodiment of the present invention.

Fig. 5 is an electrical wiring diagram of the primary control circuit, the secondary alarm circuit, and the surge suppression circuit of an embodiment of the present invention.

FIG. 6 is an electrical wiring diagram of a voltage regulator circuit according to an embodiment of the present invention.

Fig. 7 is an electrical wiring diagram of a power supply circuit of an embodiment of the present invention.

Fig. 8 is an electrical wiring diagram of a first voltage sampling circuit of an embodiment of the present invention.

Fig. 9 is an electrical wiring diagram of the secondary control circuit, the overheat protection circuit, and the first alarm circuit according to the embodiment of the present invention.

Fig. 10 is an electrical wiring diagram of a second voltage sampling circuit of the embodiment of the present invention.

FIG. 11 is an electrical wiring diagram of a protection circuit according to an embodiment of the present invention

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Examples

As shown in fig. 1, the present embodiment provides a control method for low-voltage electric heating film with one-to-N interactive control, including:

1 transformer is adopted to supply power for the electrothermal film heating systems in the N heating units; wherein N is not less than 2 and is an integer;

the temperature of the N heating units is monitored through the N temperature controllers to judge whether the corresponding electrothermal film heating system needs to work or not;

and selecting to carry out all work or interactive work on the electrothermal film heating system needing to work through power judgment.

The principle is as follows: the 'one-to-N' heating method means that a transformer is used for supplying power and heating to N heating units, wherein the heating units can be a room or an area in the room, an electric heating film heating system is arranged in each heating unit, and each electric heating film heating system consists of a plurality of electric heating films. Therefore, the invention firstly adopts 1 transformer to supply power for the electrothermal film heating systems in N heating units, realizes that the capacity of the former N transformers is integrated on a large-capacity transformer, and if the N electrothermal film heating systems work simultaneously, the rated power of the transformer needing large capacity needs to be larger than the total power of the N electrothermal film heating systems when working, so the volume and the weight of the transformer are overlarge, the construction is inconvenient, the cost is high, and the power consumption of the transformer is increased. Therefore, the temperature of the N heating units is monitored by the N temperature controllers to judge whether the corresponding electrothermal film heating system needs to work or not, and when the total power of the electrothermal film system needing to work is less than the rated power of the transformer, the electrothermal film heating system needing to work is completely worked; when the total power of the electrothermal film heating system needing to work exceeds the rated power of the transformer, the electrothermal film heating system needing to work is interactively controlled, namely, only the electrothermal film heating system needing to work is controlled to work at the same moment, the rated power of the transformer only needs to be larger than the total power of the electrothermal film heating system working, and does not need to be larger than the total power of all N electrothermal film heating systems, so that the size and the weight of the transformer can be reduced, the utilization rate of the transformer is greatly improved, and the capacity of a power grid which needs to be configured by the heating system is greatly reduced.

As shown in fig. 2, the method for supplying power to the electrothermal film heating systems in the N heating units by using 1 transformer includes:

employing a transformer having 1 primary winding and at least N secondary windings;

connecting the primary winding of the transformer with a power supply to form an input circuit; the N secondary windings of the transformer are respectively and correspondingly connected with the electrothermal film heating systems of the N heating units to form N output branches;

and the power supply supplies power to the electrothermal film heating systems in the N heating units sequentially through the input circuit and the N output branches.

The control method for one-to-N interactive control of low-voltage electric heating film electric heating further comprises the following steps: and performing on-off control on the input circuit. Specifically, the method for controlling the on/off of the input circuit includes:

the method comprises the following steps that a primary control circuit is adopted, the action end of the primary control circuit is connected into an input circuit, and a control unit is adopted to control the control end of the primary control circuit;

the control of the power supply of the control unit is realized by adopting N temperature controllers:

(1) when at least one of the N temperature controllers is in a power-on state, the temperature controllers supply power to the control unit, the control unit controls the control end of the primary control circuit to close the action end of the primary control circuit, and the input circuit is conducted;

(2) when the N temperature controllers are all in the shutdown state, the temperature controllers power off the control unit, and the control unit has no input to the control end of the primary control circuit, so that the action end of the primary control circuit is disconnected, and the input circuit is disconnected.

In some embodiments, the circuit structure for controlling the on/off of the input circuit is: the primary control circuit comprises an alternating current-direct current power supply conversion module, a first relay, a power supply circuit and a voltage stabilizing circuit; the switch contact of the first relay is used as the action end of the primary control circuit and is connected to the input circuit; the control end of the control unit is connected with a coil of the first relay through a power supply circuit;

the first signal output ends of the N temperature controllers are connected with the signal receiving end of the control unit through N second relays; the first signal output ends of the N temperature controllers are respectively connected to two ends of the coils of the N second relays; after the switch contacts of the N second relays are connected in parallel, one end of each switch contact is connected with the output end of the alternating current-direct current power supply conversion module, and the other end of each switch contact is connected with the power supply end of the control unit through the voltage stabilizing circuit. As shown in fig. 3, 4, 5, and 6, the input end of the ac/DC power supply module inputs ac voltage of 220V/50Hz through the terminal P5 and the terminal P14, and the output end of the ac/DC power conversion module outputs DC12V voltage through the terminal S1-1 and the terminal S1-2 (the terminal S1-1 and the terminal S1-2 are connected by corresponding pins); the first relay is a relay K4, and the 3 second relays are a relay K6, a relay K13 and a relay K14 respectively; the switch contact (pin 4 and pin 5) of the relay K4 is connected in the input circuit as the action end of the primary control circuit, namely one end of the switch contact of the relay K4 is connected with an alternating current power supply (connected with the alternating current power supply through a terminal J3), and the other end is connected with the primary winding of the transformer; first signal output ends of the 3 temperature controllers are respectively and correspondingly connected to two ends of coils of the relay K6, the relay K13 and the relay K14 (the first signal output ends are respectively connected with a pin 2 and a pin 5 of each second relay through a terminal J4, a terminal J6 and a terminal J10); the pin 3 of the relay K6, the relay K13 and the relay K14 are connected in parallel and then connected to the output end of the alternating current/direct current power supply module (the pin 1 of the terminal S1-2 is connected with 12V +, and the pin 2 is grounded), the pin 1 of the relay K6, the relay K13 and the relay K14 are connected in parallel and then output DC12V + voltage, when at least one of the 3 temperature controllers provides a control signal through the first signal output end, the coil of the corresponding second relay is electrified, the switch contact is closed, and therefore the pin 1 of the relay K6, the relay K13 and the relay K14 are connected in parallel and then can output 12V + direct current to supply power to the power supply end VDD of the control unit (the single chip microcomputer U2) through the voltage stabilizing circuit. The voltage-stabilized power supply comprises a diode D1, a voltage-stabilizing tube U1, a capacitor C2, a capacitor C8, a capacitor C5 and a capacitor C6; pin 1 of the terminal S1 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to the input terminal of the regulator tube U1, and the output terminal of the regulator tube U1 is connected to the power supply terminal of the single chip microcomputer U2 (pin 9, VDD of the single chip microcomputer U2). One end of a capacitor C2 is connected with the input end of a voltage regulator tube U1, and one ends of a capacitor C8, a capacitor C5 and a capacitor C6 are connected with the output end of a voltage regulator tube U1; the other ends of the capacitor C2, the capacitor C8, the capacitor C5 and the capacitor C6, and the pin 2 of the terminal S1 are all grounded. And a capacitor C4 is also connected between the power supply end and the grounding end of the singlechip U2.

The primary control circuit further comprises a surge suppression circuit; the surge suppression circuit comprises an NTC thermistor R3, a second relay, a first triode and a first voltage sampling circuit; one end of the first voltage sampling circuit is connected with a coil of the first relay, and the other end of the first voltage sampling circuit is connected with a sampling end of the control unit; the control end III of the control unit is connected with a coil of the second relay through a triode; the switch contact of the second relay is connected in parallel with two ends of the NTC thermistor; the NTC thermistor is connected in series in the input circuit. As shown in fig. 5 and 8, the second relay is a relay K3, the first triode is a triode Q4, the first voltage sampling circuit includes a resistor R8 and a voltage regulator tube D5 which are connected in series, one end of the resistor R8 is connected with the coil of the relay K4, the other end of the resistor R8 is grounded through the negative electrode and the positive electrode of the voltage regulator tube D5, and an electrical connection point between the resistor R8 and the voltage regulator tube D5 is connected to the sampling end of the single chip U2 (the pin 20 of the single chip U2); the control end III of the singlechip U2 (pin 1 of the singlechip U2) is connected with (or connected with through a resistor R4) the base electrode of the triode Q4; the emitter of the triode Q4 is grounded, and the collector of the triode Q4 is connected with the coil of the relay K3; the switch contact of the relay K3 is connected in parallel at two ends of the NTC thermistor R3. Therefore, after the low-voltage electric heating film electric heating system is started, the coil voltage of the relay K4 is sampled through the first voltage sampling circuit, the sampled voltage is fed back to the singlechip U2 through the sampling end (pin 20 of the singlechip U2) of the singlechip U2, after the singlechip U2 receives the fed-back sampled voltage, delay is carried out according to preset delay time (generally set within 1s, such as 300ms), after the delay time is reached, a control signal is output to the base of the triode Q4 through the control end III (pin 1 of the singlechip U2) of the singlechip U2, the triode Q4 is conducted, power is supplied to the coil of the relay K3, the switch contact of the relay K3 is closed, the current of the NTC resistor R3 is greatly shunted, the working temperature of the NTC resistor R3 is reduced, the service life is prolonged, in addition, a light emitting diode LED1 can be connected in parallel at two ends of the coil of the relay K3, to effect indication of the operation of the surge suppression circuit.

The power supply circuit comprises a first power supply circuit, a second power supply circuit and a two-gear toggle switch SW 1; two control ends I of the control unit (pin 2 and pin 3 of the singlechip U2) pass through the input ends of the first power supply circuit and the second power supply circuit respectively; the first path of input end of the two-gear toggle switch is connected with the output end of the first power supply circuit, the second path of input end of the two-gear toggle switch is connected with the output end of the second power supply circuit, and the output end of the two-gear toggle switch is connected with the coil of the first relay. Furthermore, the first power supply circuit and the second power supply circuit both comprise a third relay, a second triode and a first diode; the control end of the control unit is connected with the base electrode of the second triode; the emitter of the second triode is grounded; the collector of the second triode is connected with a direct-current power supply through a coil of the third relay on one hand, and is connected with the direct-current power supply through the anode and the cathode of the first diode on the other hand; one end of a switch contact of the third relay is connected with the direct-current power supply, and the other end of the switch contact is connected with the input ends of the two-gear toggle switch. As shown in fig. 4 and 7, the power supply circuit includes a transistor Q1 (second transistor), a diode D3 (first diode), and a relay K1 (third relay); a first control end (pin 3 of the singlechip U2) of the singlechip U2 is connected with (or connected with through a resistor R1) a base electrode of a triode Q1; the emitter of the transistor Q1 is grounded; the collector of the triode Q1 is connected with a direct current power supply through the anode and the cathode of the diode D3 on one hand, and is connected with the direct current power supply through the coil of the relay K1 on the other hand; pin 1 of the relay K1 is connected to a dc power supply, and pin 4 is the output of the first power supply circuit. When the single chip microcomputer U2 outputs a control signal through a first control end (pin 3 of the single chip microcomputer U2) to reach the base electrode of the triode Q1 through the resistor R1 to enable the triode Q1 to be conducted, then the direct current power supply supplies power to the coil of the relay K1 to enable the switch contact of the relay K1 to be closed (pin 1 and pin 4 of the relay K1 to be conducted), and then the power is supplied through the pin 4 of the relay K1 as the output end of the first power supply circuit. The power supply circuit II comprises a triode Q2, a diode D4 and a relay K2 which are sequentially connected, the power supply circuit I and the power supply circuit II have the same structure, and manual switching of a maintainer to the power supply circuit I and the power supply circuit II is achieved through a two-gear toggle switch SW 1. By arranging two identical power supply circuits, the forced execution of the first maintenance can be realized, specifically as follows: when the low-voltage electric heating film electric heating system leaves a factory, the second power supply circuit is used for supplying power to the later-stage circuit, the second power supply circuit is not connected, first maintenance time (such as 480 hours) is preset in the single chip microcomputer U2, and when the preset first maintenance time is reached after the low-voltage electric heating film electric heating system is started for the first time, the single chip microcomputer U2 stops outputting control signals to the second power supply circuit, so that the low-voltage electric heating film electric heating system stops working, and the normal work of the heating system is recovered after the second power supply circuit is switched to the first power supply circuit by a maintainer.

The method for judging whether the corresponding electrothermal film heating system needs to work by monitoring the temperature of the N heating units through the N temperature controllers comprises the following steps:

presetting a temperature threshold in the N temperature controllers, wherein the temperature threshold is a target temperature value set by a user;

when the temperature controller monitors that the indoor temperature of the heating unit does not reach a preset temperature threshold value, all electrothermal film heating systems in the heating unit corresponding to the temperature controller need to work; when the temperature controller monitors that the indoor temperature of the heating unit reaches a preset temperature threshold value, all the electrothermal film heating systems in the heating unit corresponding to the temperature controller do not need to work.

The method for selecting to carry out all work or interactive work on the electrothermal film heating system needing to work through power judgment comprises the following steps:

when M electrothermal film heating systems need to work, N is more than or equal to M and is more than or equal to 1, and M is an integer, the rated power P1 of the transformer is compared with the total power P2 of the M electrothermal film heating systems when the M electrothermal film heating systems work:

when P1 is more than or equal to P2, controlling all output branches corresponding to the M electrothermal film heating systems to be conducted;

when P1 < P2, the corresponding output branches of the M electrothermal film heating systems are controlled to be alternately conducted.

Specifically, the method for controlling the output branches corresponding to the M electrothermal film heating systems to be fully conducted or alternatively conducted includes:

a secondary control circuit is adopted, the secondary control circuit comprises N control branches, action ends of the N control branches are respectively and correspondingly connected to the N output branches, and a control unit is adopted to control the control ends of the N control branches;

when the temperature controller judges that the corresponding electrothermal film heating system needs to work, a control signal is input to the control unit, and the control unit compares the rated power P1 of the transformer with the total power P2 of the M electrothermal film heating systems during working:

when P1 is not less than P2, the control unit provides control signals to the control ends of the control branches corresponding to the M electrothermal film heating systems, so that the action ends of the corresponding control branches are closed, and the output branches corresponding to the M electrothermal film heating systems are controlled to be completely conducted;

when P1 < P2, the control unit provides control signals to the control ends of the M electrothermal film heating systems corresponding to the control branches alternately, so that the action ends of the corresponding control branches are closed alternately, and the output branches corresponding to the M electrothermal film heating systems are controlled to be switched on alternately.

In some embodiments, the circuit structure for performing interactive control on the M electrothermal film heating systems is as follows: each control branch comprises a fourth relay, a third triode, a second voltage sampling circuit and a solid-state relay; one path of the second signal output end of the corresponding temperature controller is connected with one end of a switch contact of the fourth relay on one hand, and is connected with a second signal receiving end of the control unit through a second voltage sampling circuit on the other hand; the other end of the switch contact of the fourth relay and the other path of the second signal output end of the temperature controller are respectively connected with two ends of the solid-state relay coil; a switch contact of the solid-state relay is connected in the output branch as an action end of the control branch; one end of a coil of the fourth relay is connected with the output end of the power supply circuit, and the other end of the coil of the fourth relay is grounded through a collector and an emitter of the third triode in sequence; and the base electrode of the third triode is used as the control end of the control branch and is connected with the second control end of the control unit. As shown in fig. 9 and 10, the fourth relay is a relay K7, a relay K8, and a relay K9, and the third transistor is a transistor Q3, a transistor Q5, and a transistor Q6; one of the second signal output ends of the 3 temperature controllers is correspondingly connected with a pin 4 of a relay K7, a relay K8 and a relay K9 through a pin 1 of a terminal DZ4, a terminal DZ5 and a terminal DZ6 on the one hand, and is connected with a second signal receiving end (a pin 17, a pin 18 and a pin 19 of a singlechip U2) of a singlechip U2 through a second voltage sampling circuit on the other hand, and each second voltage sampling circuit comprises a resistor (a resistor R12, a resistor R13 and a resistor R14) and a voltage regulator tube (a voltage regulator tube D6, a voltage regulator tube D7 and a voltage regulator tube D8) which are connected in series; the other path of the pin 3 of the relay K7, the relay K8, the relay K9 and the second signal output end of the temperature controller is respectively connected with two ends of a solid-state relay coil; pins 2 of the relay K7, the relay K8 and the relay K9 are connected with the output end of the power supply circuit, and pins 1 are grounded through the collector electrodes and the emitter electrodes of the corresponding triode Q3, the triode Q5 and the triode Q6; the base electrodes of the triode Q3, the triode Q5 and the triode Q6 are used as the control ends of the control branch and correspondingly connected (or connected through a resistor R5, a resistor R7 and a resistor R9) with the control end II of the singlechip U2 (the pin 8, the pin 10 and the pin 11 of the singlechip U2); therefore, when the corresponding temperature controller provides a control signal to the single chip microcomputer U2, the single chip microcomputer U2 can control the conduction of the corresponding triode Q3, the triode Q5 and the triode Q6 according to the control signal output by the control end two (the pin 8, the pin 10 and the pin 11 of the single chip microcomputer U2), so that the coils of the corresponding relay K7, the relay K8 and the relay K9 are electrified, the switch contacts of the corresponding relay K7, the relay K8 and the relay K9 are closed, the coils of the corresponding solid-state relays are electrified, the switch contacts are closed, and the corresponding output branches are conducted.

Wherein, the control M electric heat membrane heating system's the output branch road that corresponds switches on in turn means: presetting a working period in a control unit, and dividing M electrothermal film heating systems into a first part and a second part; in a working period, controlling all output branches corresponding to the first part of electric heating film heating system to be switched on, and controlling all output branches corresponding to the second part of electric heating film heating system to be switched off; in the next working period, controlling all output branches corresponding to the second part of electric heating film heating system to be switched on, and controlling all output branches corresponding to the first part of electric heating film heating system to be switched off; therefore, the output branches corresponding to the electrothermal film heating systems of the first part and the second part of the M electrothermal film heating systems are controlled to be alternately conducted in a working period. For example, when the first part of the electric heating film heating system R1 and the second part of the electric heating film heating system R2 need to operate, and the rated power of the transformer is greater than the operating power of the first part of the electric heating film heating system R1 but less than the operating power of the second part of the electric heating film heating system R2, because the first part of the electric heating film heating system R1 and the second part of the electric heating film heating system R2 cannot operate simultaneously, in a first operating cycle, the control unit controls the switch contact of the relay K7 to be closed, and then the switch contact of the corresponding solid-state relay is closed, so that the output branch corresponding to the first part of the electric heating film heating system R1 is conducted, the electric heating film heating system R1 operates, and the electric heating film heating system R2 does not operate; in the next working period, the control unit controls the switch contact of the relay K8 to be closed, then the switch contact of the corresponding solid-state relay is closed, so that the output branch corresponding to the second electrothermal film heating system R2 is conducted, the electrothermal film heating system R2 works, and the electrothermal film heating system R1 does not work. If the first part of the electric heating film heating system R1 and the second part of the electric heating film heating system R2 work alternately through interactive control, the transformer with rated power smaller than the total working power of the first part of the electric heating film heating system and the second part of the electric heating film heating system can drive the first part of the electric heating film heating system and the second part of the electric heating film heating system to work through interactive control, and the temperature of the corresponding heating unit reaches a preset temperature threshold value.

In some embodiments, the control method for controlling the one-to-N interactive control of the low-voltage electric heating film further comprises: and carrying out overheat protection on the electrothermal film heating system. I.e. the secondary control circuit further comprises a first overheat protection circuit; the first overheating protection circuit comprises N overheating protection branch circuits formed by a plurality of normally closed self-recovery temperature fuses connected in series; one end of a coil of the fourth relay is connected with the output end of the power supply circuit through the N overheating protection branches. As shown in fig. 9, the 3 overheating protection branches are respectively connected between the output end of the power supply circuit and one end of the coil of the relay K7, the relay K8 and the relay K9 through the terminal DZ1, the terminal DZ2 and the terminal DZ3, and the 3 overheating protection branches are arranged under the corresponding 3 electrothermal film heating systems, when the heating temperature of the electrothermal film heating system exceeds the operating temperature of the normally closed self-recovery temperature fuse in any overheating protection branch, the normally closed self-recovery temperature fuse is disconnected, so that the corresponding output branch is disconnected, and further the corresponding electrothermal film heating system stops working.

Further, the secondary control circuit further comprises a first alarm circuit; the first alarm circuit comprises a fifth relay and a first alarm device; the output end of the power supply circuit is connected with a first alarm device through a switch contact of a fifth relay; one end of a coil of the fifth relay is grounded, and the other end of the coil is connected with the output end of the power supply circuit through the normally closed self-recovery temperature fuse. As shown in fig. 9, the fifth relay is a relay K10, a relay K11, a relay K12, and the first alarm device is a buzzer F2. Pin 1 of relay K10, relay K11 and relay K12 is connected to the output of the power supply circuit, pin 3 is connected to buzzer F2, pin 5 is grounded, and pin 2 is connected to the output of the power supply circuit by a normally closed self-restoring temperature fuse (corresponding to terminal DZ1, terminal DZ2 and terminal DZ 3). Diodes (a diode D9, a diode D10, and a diode D11 are connected correspondingly) are also connected between the pin 2 of the fifth relay and the pin 1 of the fourth relay. When the heating temperature of the electrothermal film heating system exceeds the action temperature of the normally closed self-recovery temperature fuse, the normally closed self-recovery temperature fuse is disconnected, so that the corresponding output branch circuit is disconnected, the corresponding electrothermal film heating system is further stopped working, the coil voltages of the corresponding relay K10, the relay K11 and the relay K12 are simultaneously opened, the pin 1 and the pin 3 are connected, the power supply circuit supplies power for the buzzer F2, and the buzzer F2 sends out a buzzer to give an alarm.

In some embodiments, the control method for controlling the one-to-N interactive control of the low-voltage electric heating film further comprises: and performing overheat protection and overcurrent protection on the transformer. Namely, the primary control circuit also comprises a second overheating protection circuit and an overcurrent protection circuit; the second overheating protection circuit is formed by connecting a plurality of normally closed self-recovery temperature fuses in series; the overcurrent protection circuit is a plurality of current induction switches connected in series; the control end of the control unit is connected with the coil of the first relay through the power supply circuit, the overheating protection circuit and the overcurrent protection circuit. As shown in fig. 5 and 11, the one or more normally closed self-recovery temperature fuses connected in series and the plurality of current sensing switches connected in series are implemented by a terminal P8, a terminal P9 and the like, and the normally closed self-recovery temperature fuse in the second overheating protection circuit is arranged inside the transformer, when the temperature of the transformer exceeds the operating temperature of the normally closed self-recovery temperature fuse, the normally closed self-recovery temperature fuse is opened, the coil of the relay K4 has no voltage and the contact thereof is opened, so that the power port cannot be conducted with the transformer through the NTC thermistor R3, the transformer has no input voltage, and all the electrothermal film heating systems stop heating; detecting the working current of the transformer through a current induction switch; when the current induction switch detects that the current of the transformer exceeds a set current value, the signal end of the current induction switch is opened and self-locked, and therefore the coil of the relay K4 is not disconnected with a contact of the relay without voltage, so that a power port cannot be conducted with the transformer through the NTC thermistor R3, the transformer has no input voltage, and all the electrothermal film heating systems stop heating.

Further, the primary control circuit further comprises a second alarm circuit; the second alarm circuit comprises a sixth relay and a second alarm device; the output end of the power supply circuit is connected with an alarm device through a switch contact of a sixth relay; one end of the coil of the sixth relay is grounded, and the other end of the coil of the sixth relay is connected with the coil of the first relay. As shown in fig. 5, the sixth relay is a relay K5, and the second alarm device is a buzzer B1, that is, the second alarm circuit includes a relay K5 and a buzzer B1; the output end of the power supply circuit is connected with a pin 1 of a relay K5, and a pin 3 of a relay K5 is connected with a buzzer B1; the coil of relay 5 is connected to the coil of relay K4. When the temperature of the transformer exceeds the action temperature of a plurality of normally closed self-recovery temperature fuses in the second overheating protection circuit, the coil of the relay K4 has no voltage and the contact thereof is disconnected, so that the power port cannot be conducted with the transformer through the NTC thermistor R3, the transformer has no input voltage, and all electrothermal film heating systems stop heating; meanwhile, the coil of the relay K5 has no voltage, and at the moment, the pin 1 and the pin 3 of the relay K5 are conducted, so that the power supply circuit supplies power to the buzzer B1, and the buzzer B1 sends out a buzzing sound to give an alarm; when the current induction switch detects that the current of the transformer exceeds a set current value, the signal end of the current induction switch is opened and self-locked, and therefore the coil of the relay K4 is free of voltage and the contact of the coil is disconnected, so that a power supply port cannot be conducted with the transformer through the NTC thermistor R3, the transformer is free of input voltage, each electrothermal film heating system stops heating, meanwhile, the coil of the relay K5 is free of voltage, at the moment, the pin 1 and the pin 3 of the relay K5 are conducted, the power supply circuit supplies power for the buzzer B1, and the buzzer B1 sends out a buzzing alarm.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.