Air conditioning system

Abstract

The invention discloses an air conditioning system, which comprises a plurality of slave machines, each slave machine is used for acquiring corresponding power supply information and outputting power transmission request information when the power supply information comprises power failure information; the host is electrically connected with the multiple slaves through a bus, and the host is used for determining the slaves as target slaves when receiving the power transmission request information, determining other slaves except the target slaves as non-target slaves and sending power transmission instructions to the non-target slaves; the non-target slave is used for switching from the communication mode to the power supply mode when receiving the power transmission instruction so as to supply power to the target slave and drive the solenoid valve of the target slave to be disconnected; according to the technical scheme, the situation that the air conditioner system works abnormally due to the fact that the electromagnetic valve cannot be closed when the indoor unit loses power is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioners, and in particular to an air conditioning system. Background Art

[0002] In a multi-split air conditioning unit, one main unit is often used to drive multiple indoor units. Since different indoor units are installed in a distributed manner, the electricity drawn by the indoor units may not be in the same power grid, so it cannot be guaranteed that the power supply of each indoor unit is in a normal state. Under the influence of external factors, or when there is an abnormality in the switch power supply of the indoor unit, the indoor unit may lose power. At this time, the solenoid valve of the indoor unit always maintains the state before the power failure. If the user's indoor unit is in cooling mode before the power failure, the refrigerant will be connected after the power failure because the solenoid valve remains open. Because the fan stops working, the cold air gathers near the condenser and cannot be blown out, causing the evaporator of the indoor unit to frost. In severe cases, it will affect the operation of the entire refrigeration system. Summary of the invention

[0003] The main purpose of the present invention is to provide an air conditioning system, aiming to reduce the occurrence of abnormal operation of the air conditioning system due to the inability to close the solenoid valve when the indoor unit loses power.

[0004] To achieve the above object, the air conditioning system proposed by the present invention comprises:

[0005] A plurality of slaves, each of the slaves is used to obtain corresponding power supply information, and output power supply request information when the power supply information includes power-off information;

[0006] A host, electrically connected to the plurality of slaves through a bus, the host being used to determine the slave as a target slave upon receiving the power transmission request information, and to determine other slaves except the slave as non-target slaves, and to send a power transmission instruction to the non-target slaves;

[0007] The non-target slave is used to switch from the communication mode to the power supply mode when receiving the power supply instruction, so as to supply power to the target slave and drive the electromagnetic valve of the target slave to be disconnected.

[0008] In some embodiments, the non-target slave is further configured to count time after switching to the power supply mode, and to switch from the power supply mode to the communication mode when the count reaches a first preset time.

[0009] In some embodiments, the host is further configured to switch from the communication mode to the power supply mode after outputting a power supply instruction, so as to supply power to the target slave.

[0010] In some embodiments, the host is further configured to count time after switching to the power supply mode, and to switch from the power supply mode to the communication mode when the timing reaches a second preset time.

[0011] In some embodiments, the target slave is further configured to switch from the communication mode to the power receiving mode when the power-off information is acquired, and to switch from the power receiving mode to the communication mode after the solenoid valve is disconnected.

[0012] In some embodiments, the slave includes:

[0013] A power interface and a ground interface, wherein the power interface is used to connect to an external power source and the ground interface is grounded;

[0014] The selection circuit comprises a first channel and a second channel, wherein an input end of the first channel and an input end of the second channel are respectively connected to the bus, and two output ends of the first channel are respectively connected to the power interface and the ground interface;

[0015] The control circuit includes a control end and two communication ends, wherein the two communication ends are respectively connected to the two output ends of the second channel in a one-to-one correspondence, and the control end is connected to the controlled end of the selection circuit. The control circuit is used to control the switching of the first channel and the second channel.

[0016] In some embodiments, the bus includes a power line and a ground line, and the selection circuit includes:

[0017] A first switch, whose input end is used to connect to the power line, whose first output end is connected to the power interface, and whose second output end is connected to a communication end of the control circuit;

[0018] A second switch, whose input end is used to connect to the ground line, whose first output end is connected to the ground interface, and whose second output end is connected to another communication end of the control circuit;

[0019] A coil, a first end of which is used to connect to a power line;

[0020] The optocoupler has a first end on its light-emitting side connected to a first power source, a second end on its light-emitting side electrically connected to the control circuit, a first end on its receiving side connected to the ground wire, and a second end on its receiving side connected to the second end of the coil.

[0021] In some embodiments, the control circuit comprises:

[0022] A communication circuit, comprising a first differential end, a second differential end, a first transmitting end and a first receiving end, wherein the first differential end and the second differential end are two communication ends of the control circuit;

[0023] A processor, comprising a detection end, a second transmitting end and a second receiving end, wherein the second transmitting end is connected to the first receiving end, and the second receiving end is connected to the first transmitting end;

[0024] A sampling circuit, connected in series between the power interface and the detection end, the sampling circuit is used to collect power parameters of the external power supply;

[0025] The processor is used to communicate with the host through the communication circuit, and determine the power supply information according to the received power supply parameter.

[0026] In some embodiments, the control circuit further comprises:

[0027] A delay circuit is connected in parallel to the power supply terminal of the processor and the ground terminal of the processor, and the delay circuit is used to output the stored electric energy to the processor when the external power supply stops being connected;

[0028] The processor is further configured to control the first channel to be turned on within a delay time after outputting the power transmission request information, according to the acquired bus idle information, so as to connect the external power source output by the bus.

[0029] In some embodiments, the slave device further includes:

[0030] A power supply management circuit, whose input end is connected to the power supply interface, and whose output end is respectively connected to the power supply end of the control circuit and the power supply end of the selection circuit. The power supply management circuit is used to power the control circuit and the selection circuit after voltage conversion processing of the external power supply.

[0031] The technical solution of the present invention utilizes the scheme of connecting through a bus in a multi-split air-conditioning system to time-share multiplex the bus, so that when the power supply information obtained by any slave includes power-off information, it can output a power supply request to the host, and the host controls other slaves to connect their respective external power supplies to the bus, power the slaves, and drive them to close the solenoid valve, thereby reducing the influence of external factors on the air-conditioning system, or when there is an abnormality in the switch power supply of the indoor unit, the indoor unit will lose power, causing the solenoid valve to remain open to connect the refrigerant, causing the evaporator of the indoor unit to frost, and even the air-conditioning system to work abnormally. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0033] Figure 1 It is a structural schematic diagram of an embodiment of an air conditioning system of the present invention;

[0034] Figure 2 It is a structural schematic diagram of another embodiment of the air conditioning system of the present invention;

[0035] Figure 3 It is a structural schematic diagram of another embodiment of the air conditioning system of the present invention;

[0036] Figure 4 It is a structural schematic diagram of another embodiment of the air conditioning system of the present invention;

[0037] Figure 5 A circuit diagram of an air conditioning system according to an embodiment of the present invention;

[0038] Figure 6 A circuit diagram of another embodiment of the air conditioning system of the present invention;

[0039] Figure 7 It is a schematic diagram of a flow chart of an embodiment of an air conditioning system of the present invention.

[0040] Description of Figure Numbers:

[0041] Label name Label name 100 Slave 133 Sampling circuit 111 Power interface 134 Delay Circuit 112 Ground interface 140 Power management circuit 120 Select Circuit 200 Host 121 First Channel S1~S2 First switch~Second switch 122 Second channel L1 Coil 130 Control Circuit U1 Optocoupler 131 Communication circuit R1 Sampling resistor 132 processor R2 Voltage Divider Resistors

[0042] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0045] The invention provides an air conditioning system.

[0046] Reference Figure 1 and Figure 7 In one embodiment, the air conditioning system comprises:

[0047] A plurality of slave machines 100, each of the slave machines 100 is used to obtain corresponding power supply information, and output power supply request information when the power supply information includes power-off information;

[0048] The host 200 is electrically connected to the plurality of slaves 100 through a bus, and the host 200 is used to determine that the slave 100 is a target slave when receiving the power transmission request information, and to determine that other slaves except the slave are non-target slaves, and send a power transmission instruction to the non-target slaves;

[0049] The non-target slave is used to switch from the communication mode to the power supply mode when receiving the power supply instruction, so as to supply power to the target slave and drive the electromagnetic valve of the target slave to be disconnected.

[0050] It should be noted that in a one-to-many air conditioning system, the host 200 is usually an air conditioner outdoor unit, which is used for unified heat exchange with the outside world, and the slave 100 is an air conditioner indoor unit, which is used for heat exchange with indoor air. The condenser of each indoor unit transmits refrigerant with the host 200 through a pipeline, and the opening and closing of the condenser inlet is controlled by an electric control valve. When the slave 100 loses power due to external factors or an abnormal switch power supply, the pipeline continues to transmit refrigerant to the condenser because the electric control valve is not closed after the power is lost. At the same time, the fan of the indoor unit stops due to power failure, resulting in cold air gathering around the condenser in the slave 100.

[0051] In this embodiment, the initial operating states of the slave 100 and the host 200 are both in a communication state. In this state, multiple slaves 100 communicate with the host 200 through the bus to transmit load information, environmental information and other data. When the slave 100 is working, it collects the power supply information of the external power supply in real time, and the power supply information may include input voltage, input current or input power, etc. When the external power supply is detected to be powered off according to the power supply information, it is confirmed that the power supply information includes power off information, such as detecting that the input voltage is lower than the preset low voltage value, the input current is lower than the preset undercurrent value, etc. At this time, the slave 100 outputs the power supply request information with the address of the slave 100 to the host 200 through the bus.

[0052] When the host 200 receives the power transmission request information, it confirms the target slave according to the address in the information. At this time, the host 200 confirms the other slaves 100 except the target slave as non-target slaves, and outputs a power transmission instruction to at least one non-target slave through the bus.

[0053] When any slave 100 receives the power transmission instruction, the slave 100 switches its current operation mode to the power supply mode. It can be understood that the power supply mode is to connect the bus to the external power supply connected to the slave 100 through the internal circuit action of the slave 100, so that the bus changes from transmitting communication data to transmitting external power. Thus, using the transmission principle of current from high potential to low potential, the external power in the bus is output to the slave 100 that loses power, so that it uses the power output from the bus to drive the solenoid valve to close, preventing the refrigerant from continuing to transmit.

[0054] The technical solution of the present invention utilizes the scheme of connecting through a bus in a multi-split air-conditioning system to time-share the bus, so that when the power supply information obtained by any slave machine 100 includes power-off information, it can output a power supply request to the host machine 200, and the host machine 200 controls other slave machines 100 to connect their respective external power supplies to the bus, power the slave machines 100, and drive them to close the solenoid valve, thereby reducing the influence of external factors on the air-conditioning system, or when there is an abnormality in the switch power supply of the indoor unit, the indoor unit will lose power, causing the solenoid valve to remain open to connect the refrigerant, causing the evaporator of the indoor unit to frost, and even the air-conditioning system to work abnormally.

[0055] Furthermore, in addition to controlling the non-target slave to supply power to the target slave, the host 200 is also used to switch from the communication mode to the power supply mode after outputting a power supply instruction, so as to supply power to the target slave.

[0056] Reference Figure 1 and Figure 7 In one embodiment, the non-target slave is further used to count time after switching to the power supply mode, and when the timing reaches a first preset time, switch from the power supply mode to the communication mode.

[0057] It is understandable that the non-target slave sets the power supply mode only to drive the target slave to close the solenoid valve. If the power supply is continued, it will affect the communication between it and the host 200, causing the host 200 to be unable to obtain the working status of the non-target slave in time.

[0058] Since the non-target slave cannot communicate with the host 200 or other slaves 100 in the power supply mode, it is impossible to determine when the communication should be re-established. Therefore, in this embodiment, a first preset time is set in the slave 100. The first preset time should take a redundant value based on the normal action time of the solenoid valve, such as 1 minute, 2 minutes, etc. After the slave 100 receives the power supply instruction and is switched to the power supply mode as a non-target slave, it starts timing the first preset time and switches to the communication mode after the timing ends, so as to communicate with the host 200 in time and transmit the current working data.

[0059] Similarly, in another embodiment, the host 200 is further configured to count time after switching to the power supply mode, and when the count reaches a second preset time, switch from the power supply mode to the communication mode.

[0060] In this embodiment, the second preset time also takes a redundant value according to the normal action time of the solenoid valve, and the second preset time may be the same as or different from the first preset time.

[0061] After the host 200 switches to the power supply mode, it starts to count the second preset time, and switches to the communication mode after the timing ends, broadcasting normal communication information to the bus, so as to restore the normal communication state of the bus in time.

[0062] Reference Figure 1 and Figure 7 In one embodiment, the target slave is further configured to switch from the communication mode to the power receiving mode when the power-off information is acquired, and to switch from the power receiving mode to the communication mode after the solenoid valve is disconnected.

[0063] In this embodiment, the power receiving mode is the same as the above-mentioned power supply mode. Through the operation of the internal circuit of the slave 100, the bus is connected to the power supply end inside the slave 100, so that other slaves 100 or the host 200 connected to the bus output external power to the inside of the slave 100, driving the slave 100 to power on and drive the solenoid valve to close.

[0064] At the same time, in order to prevent the target slave from remaining in the power receiving mode after the power grid is restored, so that the connected external power supply is reversely input into the bus, affecting the normal communication between the host 200 and other slaves 100, the target slave counts the third preset time after disconnecting the solenoid valve, and switches from the power receiving mode to the communication mode. The third preset time can be a redundant time such as 10s, 15s, etc.

[0065] Reference Figure 2 In one embodiment, the slave 100 includes:

[0066] A power interface 111 and a ground interface 112, wherein the power interface 111 is used to connect to an external power source, and the ground interface 112 is grounded;

[0067] The selection circuit 120 includes a first channel 121 and a second channel 122, wherein an input end of the first channel 121 and an input end of the second channel 122 are respectively connected to the bus, and two output ends of the first channel 121 are respectively connected to the power interface 111 and the ground interface 112;

[0068] The control circuit 130 includes a control end and two communication ends. The two communication ends are respectively connected to the two output ends of the second channel 122 in a one-to-one correspondence. The control end is connected to the controlled end of the selection circuit 120. The control circuit 130 is used to control the switching of the first channel 121 and the second channel 122.

[0069] In this embodiment, the power interface 111 can be connected to a switching power supply, BMS (power management system), etc. in the indoor unit, and the external power outputted by the power interface 111 is connected to power the host 200.

[0070] The first channel 121 is used to connect the power interface 111 to the bus, and the second channel 122 is used to connect the communication end of the control circuit 130 to the bus. Specifically, when the slave 100 is working, the second channel 122 is turned on by default, and the first channel 121 is turned off by default. At this time, the control circuit 130 can communicate with the host 200 through the bus. After the slave 100 receives the power transmission instruction or sends the power transmission request instruction, the control chip controls the first channel 121 to be turned on, the second channel 122 to be turned off, and the power interface 111 of the slave 100 is connected to the main line. If the slave 100 is powered off at this time, that is, it is a non-target slave, the external power supply connected to the power interface 111 will also be connected to the bus transmission; if the slave 100 is powered off at this time, that is, it is a target slave, after the power interface 111 is connected to the bus, the external power supply of the host 200 and / or other slaves 100 transmitted by the bus will be connected to the slave 100 for power supply.

[0071] The ground interface 112 is used to form a current loop with the power interface 111 when the first channel 121 is connected.

[0072] Reference Figure 2 , Figure 5 and Figure 6 In one embodiment, the bus includes a power line and a ground line, and the selection circuit 120 includes:

[0073] A first switch S1, whose input end is used to connect to the power line, whose first output end is connected to the power interface 111, and whose second output end is connected to a communication end of the control circuit 130;

[0074] A second switch S2, whose input end is used to connect to the ground line, whose first output end is connected to the ground interface 112, and whose second output end is connected to another communication end of the control circuit 130;

[0075] The coil L1 has a first end for connecting to a power line;

[0076] The optocoupler U1 has a first end on the light-emitting side connected to the first power source, a second end on the light-emitting side electrically connected to the control circuit 130, a first end on the receiving side connected to the ground wire, and a second end on the receiving side connected to the second end of the coil L1.

[0077] In this embodiment, the first switch S1 and the second switch S2 are single-pole double-throw switches. In a default state, the first switch S1 and the second switch S2 are respectively connected to two communication terminals of the control circuit 130, so that the initial state of the slave 100 is a communication state.

[0078] When the slave 100 is working normally, the control circuit 130 collects the power supply information at the power interface 111 in real time. When it is found that the power supply information does not include the power-off information, the control circuit 130 outputs a shutdown control signal to the optocoupler U1 to keep the optocoupler U1 turned off. At this time, the current loop of the coil L1 is disconnected, and the first switch S1 and the second switch S2 are not in action. When it is found that the power supply information includes the power-off information, the control circuit 130 outputs a conduction control signal to the optocoupler U1 to control the optocoupler U1 to be turned on. At this time, the current loop of the coil L1 is connected, and the first switch S1 and the second switch S2 are operated under the action of the coil L1 to connect the corresponding first output terminal to the input terminal.

[0079] The level of the control signal is related to the connection structure of the optocoupler U1. When the cathode of the light-emitting diode in the optocoupler U1 is connected to the processor 132, the shutdown control signal is high, that is, MCU_Control=1, and the on control signal is low, that is, MCU_Control=0.

[0080] Reference Figure 3 and Figure 5 In one embodiment, the control circuit 130 includes:

[0081] The communication circuit 131 includes a first differential end, a second differential end, a first transmitting end and a first receiving end, wherein the first differential end and the second differential end are two communication ends of the control circuit 130;

[0082] The processor 132 includes a detection end, a second transmitting end and a second receiving end, wherein the second transmitting end is connected to the first receiving end, and the second receiving end is connected to the first transmitting end;

[0083] A sampling circuit 133 is connected in series between the power interface 111 and the detection end, and the sampling circuit 133 is used to collect power parameters of the external power supply;

[0084] The processor 132 is used to communicate with the host 200 through the communication circuit 131 and determine the power supply information according to the received power supply parameter.

[0085] In this embodiment, the communication circuit 131 may include a 485 communication chip for converting bus communication and 485 communication of the processor 132 .

[0086] When the slave 100 is powered on, the sampling circuit 133 collects data from the connected external power supply through the power interface 111. Specifically, the sampling circuit 133 may include a voltage divider circuit formed by a sampling resistor R1 and at least one voltage divider resistor R2 connected in series. The change in the voltage across the sampling resistor R1 reflects the power supply parameters of the external power supply, such as the output voltage or the output current.

[0087] Thus, when the processor 132 detects that the power supply information includes power off information based on the power supply parameters, it outputs power supply request information through the communication circuit 131; or, when the power supply information does not include power off information and a power supply instruction is received through the communication circuit 131, it controls the selection circuit 120 to switch channels.

[0088] Reference Figure 3 and Figure 5 In one embodiment, the control circuit 130 further includes:

[0089] A delay circuit 134 is connected in parallel to the power supply terminal of the processor 132 and the ground terminal of the processor 132, and the delay circuit 134 is used to output the stored electric energy to the processor 132 when the external power supply stops being connected;

[0090] The processor 132 is further configured to control the first channel 121 to be turned on within a delay time after outputting the power supply request information, according to the acquired bus idle information, so as to connect the external power output by the bus.

[0091] In this embodiment, the delay circuit 134 may include a capacitor. Since the capacitor is connected to the power supply terminal of the processor 132, when the external power supply is not powered off, the capacitor can store the input electrical energy. Therefore, when the external power supply is powered off, the capacitor discharges to power the processor 132, thereby extending the working time of the processor 132 after power off.

[0092] It is understandable that the delay time obtained by the processor 132 is related to the energy storage capacity of the capacitor. The capacity of the capacitor should be designed to allow the processor 132 to send a power request signal to the bus after power failure, while having a certain amount of redundant time to wait for the bus to be idle. Its theoretical capacity can be calculated based on the charge calculation formula Q = I * t, and the capacitance calculation formula Get, that is: Wherein, Q is the charge, I is the current flowing through the capacitor, t is the delay time, C is the capacitance of the capacitor, and U is the voltage across the capacitor.

[0093] Thus, after the external power supply is turned off, the control circuit 130 can delay the power-off through the delay circuit 134, send signals and collect bus status information. The bus status information can be determined based on whether data transmission is detected in the bus, or whether the level of the bus output is a level representing an idle state. When it is detected that no data transmission exists in the bus, or the level of the bus output is a level representing an idle state, the collected bus status information is determined to be bus idle information.

[0094] Reference Figure 4 and Figure 5 In one embodiment, the slave machine 100 further includes:

[0095] The power supply management circuit 140 has an input end connected to the power supply interface 111, and an output end connected to the power supply end of the control circuit 130 and the power supply end of the selection circuit 120 respectively. The power supply management circuit 140 is used to power the control circuit 130 and the selection circuit 120 after voltage conversion processing of the external power supply.

[0096] In this embodiment, the power supply management circuit 140 is connected to the power interface 111. When the power grid in the area where the slave 100 is located is normally powered, the external power supply in the area is connected through the power interface 111; when the slave 100 is powered off and other slaves 100 and the host 200 are powered through the bus, the external power supply in other areas transmitted by the bus is connected. After the external power supply is connected, the external power supply is subjected to voltage conversion processing and outputs a power supply matching the control circuit 130 and the selection circuit 120.

[0097] Specifically, the power supply management circuit 140 may include a buck chip and a plurality of capacitors, wherein capacitors are connected in series between the input end of the buck chip and the ground, and between the output end of the buck chip and the ground, respectively, for stabilizing the power supply connected to or output by the buck chip. A PTC (thermistor) circuit may also be provided at the input end of the buck chip to prevent the buck chip from being impacted by a large current when powered on.

[0098] The above descriptions are only optional embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. An air conditioning system, characterized in that: include: A plurality of slaves, each of the slaves is used to obtain corresponding power supply information and output power supply request information when the power supply information includes power-off information; A host, electrically connected to the plurality of slaves through a bus, the host being used to determine the slave as a target slave upon receiving the power transmission request information, and to determine other slaves except the slave as non-target slaves, and to send a power transmission instruction to the non-target slaves; The non-target slave is used to switch from the communication mode to the power supply mode when receiving the power supply instruction, so as to supply power to the target slave and drive the electromagnetic valve of the target slave to be disconnected.

2. The air conditioning system according to claim 1, characterized in that: The non-target slave is further configured to count time after switching to the power supply mode, and to switch from the power supply mode to the communication mode when the count reaches a first preset time.

3. The air conditioning system according to claim 1, characterized in that: The host is also used to switch from the communication mode to the power supply mode after outputting the power supply instruction, so as to supply power to the target slave.

4. The air conditioning system according to claim 3, characterized in that: The host is further configured to count time after switching to the power supply mode, and to switch from the power supply mode to the communication mode when the count reaches a second preset time.

5. The air conditioning system according to any one of claims 1 to 4, characterized in that: The target slave is further configured to switch from the communication mode to the power receiving mode when the power failure information is acquired, and to switch from the power receiving mode to the communication mode after the solenoid valve is disconnected.

6. The air conditioning system according to claim 1, characterized in that: The slave comprises: A power interface and a ground interface, wherein the power interface is used to connect to an external power source and the ground interface is grounded; The selection circuit comprises a first channel and a second channel, wherein an input end of the first channel and an input end of the second channel are respectively connected to the bus, and two output ends of the first channel are respectively connected to the power interface and the ground interface; The control circuit includes a control end and two communication ends, wherein the two communication ends are respectively connected to the two output ends of the second channel in a one-to-one correspondence, and the control end is connected to the controlled end of the selection circuit. The control circuit is used to control the switching of the first channel and the second channel.

7. The air conditioning system according to claim 6, characterized in that: The bus includes a power line and a ground line, and the selection circuit includes: A first switch, whose input end is used to connect to the power line, whose first output end is connected to the power interface, and whose second output end is connected to a communication end of the control circuit; A second switch, whose input end is used to connect to the ground line, whose first output end is connected to the ground interface, and whose second output end is connected to another communication end of the control circuit; A coil, a first end of which is used to connect to a power line; The optocoupler has a first end on its light-emitting side connected to a first power source, a second end on its light-emitting side electrically connected to the control circuit, a first end on its receiving side connected to the ground wire, and a second end on its receiving side connected to the second end of the coil.

8. The air conditioning system according to claim 6, characterized in that: The control circuit comprises: A communication circuit, comprising a first differential end, a second differential end, a first transmitting end and a first receiving end, wherein the first differential end and the second differential end are two communication ends of the control circuit; A processor, comprising a detection end, a second transmitting end and a second receiving end, wherein the second transmitting end is connected to the first receiving end, and the second receiving end is connected to the first transmitting end; A sampling circuit, connected in series between the power interface and the detection end, the sampling circuit is used to collect power parameters of the external power supply; The processor is used to communicate with the host through the communication circuit, and determine the power supply information according to the received power supply parameter.

9. The air conditioning system according to claim 8, characterized in that: The control circuit further comprises: A delay circuit is connected in parallel to the power supply terminal of the processor and the ground terminal of the processor, and the delay circuit is used to output the stored electric energy to the processor when the external power supply stops being connected; The processor is further configured to control the first channel to be turned on within a delay time after outputting the power transmission request information, according to the acquired bus idle information, so as to connect the external power source output by the bus.

10. The air conditioning system according to claim 6, characterized in that: The slave device further comprises: A power supply management circuit, whose input end is connected to the power supply interface, and whose output end is respectively connected to the power supply end of the control circuit and the power supply end of the selection circuit. The power supply management circuit is used to power the control circuit and the selection circuit after voltage conversion processing of the external power supply.

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