Air conditioning system

Abstract

The application discloses an air conditioning system, wherein the air conditioning system comprises: a plurality of slaves, each slave is used for acquiring corresponding power supply information, and outputting power supply request information when the power supply information comprises power-off information; a master is electrically connected with the plurality of slaves through a bus, the master is used for determining that the slave is a target slave when receiving the power supply request information, and determining that other slaves except the target slave are non-target slaves, and sending a power supply instruction to the non-target slaves; the non-target slave is used for switching from a communication mode to a power supply mode to supply power to the target slave and drive an electromagnetic valve of the target slave to be disconnected when receiving the power supply instruction; and the technical scheme of the application aims to reduce the situation that the air conditioning system works abnormally due to the fact that the electromagnetic valve cannot be closed when the indoor unit loses power.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air conditioners, in particular to an air conditioning system. BACKGROUND

[0002] In a multi-connected air conditioning unit, one main machine is often used to drive multiple indoor machines. Due to the distributed installation of different indoor machine units, the electricity taken by the indoor machines may not be in the same power grid, so it cannot be guaranteed that the power supply of each indoor machine is in a normal state. Under the influence of external factors, or in the case of abnormal switch power supply of the indoor machine unit, the indoor machine may lose power, at which time the electromagnetic valve of the indoor machine always maintains the state before power failure. If the user's indoor machine is in a refrigeration mode before power failure, the refrigerant will be connected due to the open electromagnetic valve after power failure. And because the fan stops working, the cold air accumulates near the condenser and cannot be blown out, causing the evaporator of the indoor machine to frost, which may seriously affect the operation of the entire refrigeration system. SUMMARY

[0003] The main purpose of the present application is to provide an air conditioning system, which aims to reduce the situation that the air conditioning system works abnormally due to the failure of the electromagnetic valve to close when the indoor machine loses power.

[0004] To achieve the above-mentioned purpose, the air conditioning system provided by the present application comprises:

[0005] A plurality of slave machines, each of which is used to obtain corresponding power supply information and output power-on request information when the power supply information includes power failure information;

[0006] A main machine electrically connected to the plurality of slave machines through a bus, the main machine being used to determine that a slave machine is a target slave machine when receiving the power-on request information, and determine that other slave machines except the target slave machine are non-target slave machines, and send a power-on instruction to the non-target slave machines;

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

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

[0009] In some embodiments, the main machine is further used to switch from the communication mode to the power supply mode to supply power to the target slave machine after outputting the power-on instruction.

[0010] In some embodiments, the main machine is further used to time after switching to the power supply mode, and 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 a powered-off mode when the power-off information is acquired, and switch from the powered-off mode to the communication mode after the electromagnetic valve is disconnected.

[0012] In some embodiments, the slave comprises:

[0013] a power interface for accessing an external power supply, and a ground interface for grounding;

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

[0015] a control circuit comprising a control end and two communication ends, the two communication ends being connected to the two output ends of the second channel respectively, and the control end being connected to a controlled end of the selection circuit, the control circuit being configured to control the first channel and the second channel to switch on.

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

[0017] a first switch, an input end of the first switch being connected to the power line, a first output end of the first switch being connected to the power interface, and a second output end of the first switch being connected to a communication end of the control circuit;

[0018] a second switch, an input end of the second switch being connected to the ground line, a first output end of the second switch being connected to the ground interface, and a second output end of the second switch being connected to another communication end of the control circuit;

[0019] a coil, a first end of the coil being connected to the power line;

[0020] an optocoupler, a first end of an emitting side of the optocoupler being connected to a first power supply, a second end of the emitting side of the optocoupler being connected to the control circuit, a first end of a receiving side of the optocoupler being connected to the ground line, and a second end of the receiving side of the optocoupler being connected to a 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 sending end, and a first receiving end, the first differential end and the second differential end being the two communication ends of the control circuit;

[0023] a processor comprising a detection end, a second sending end, and a second receiving end, the second sending end being connected to the first receiving end, and the second receiving end being connected to the first sending end;

[0024] a sampling circuit connected in series between the power interface and the detection terminal, the sampling circuit being configured to collect the power parameter of the external power supply;

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

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

[0027] a delay circuit connected in parallel between the power terminal of the processor and the ground terminal of the processor, the delay circuit being configured to output stored electric energy to the processor when the external power supply stops being connected.

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

[0029] In some embodiments, the slave further comprises:

[0030] a power supply management circuit, an input terminal of which is connected to the power interface, and output terminals of which are connected to the power terminal of the control circuit and the power terminal of the selection circuit respectively, the power supply management circuit being configured to supply power to the control circuit and the selection circuit after voltage conversion of the external power supply.

[0031] The technical scheme of the present application can realize time-sharing multiplexing of the bus by connecting the bus in the multi-connected air conditioning system, so that when the power supply information acquired by any slave includes power-off information, the slave can output a power supply request to the host, and the host can control other slaves to connect the external power supply connected by the slaves to the bus to supply power to the slave, drive the slave to close the electromagnetic valve, thereby reducing the situation that the air conditioning system is affected by external factors, or the internal unit power supply is abnormal, the internal unit is powered off, the electromagnetic valve is kept open to connect the refrigerant, the evaporator of the internal unit is frosted, and the air conditioning system is abnormally operated. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to the structures shown in the drawings without creative labor.

[0033] Figure 1 The structure diagram of an embodiment of the air conditioning system of the present application;

[0034] Figure 2 Fig. 2 is a structural schematic diagram of another embodiment of the air conditioning system of the present application;

[0035] Figure 3 Fig. 3 is a structural schematic diagram of still another embodiment of the air conditioning system of the present application;

[0036] Figure 4 Fig. 4 is a structural schematic diagram of yet another embodiment of the air conditioning system of the present application;

[0037] Figure 5 Fig. 5 is a circuit schematic diagram of an embodiment of the air conditioning system of the present application;

[0038] Figure 6 Fig. 6 is a circuit schematic diagram of another embodiment of the air conditioning system of the present application;

[0039] Figure 7 Fig. 7 is a flow schematic diagram of an embodiment of the air conditioning system of the present application.

[0040] BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Reference Name Reference Name 100 Slave 133 Sampling circuit 111 Power interface 134 Delay circuit 112 Ground interface 140 Power supply management circuit 120 Selection circuit 200 Master 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 dividing resistor

[0042] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be apparently and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those of ordinary skill in the art without any creative work fall within the protection scope of the present application.

[0044] In addition, the description such as "first", "second" and the like in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of various embodiments can be combined with each other, but it must be based on the fact that the technical solutions can be realized by those of ordinary skill in the art. When the combination of technical solutions appears to be contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope required by the present application.

[0045] The present application provides an air conditioning system.

[0046] Referring to Figure 1 and Figure 7 In an embodiment, the air conditioning system comprises:

[0047] a plurality of slaves 100, each of which is configured to acquire corresponding power supply information and output power-on request information when the power supply information includes power-off information;

[0048] a master 200, which is electrically connected to the plurality of slaves 100 through a bus, and is configured to determine a target slave 100 when receiving the power-on request information, determine other slaves 100 as non-target slaves 100 except for the target slave 100, and send a power-on instruction to the non-target slaves 100;

[0049] The non-target slaves 100 are configured to switch from a communication mode to a power supply mode to supply power to the target slave 100 and drive an electromagnetic valve of the target slave 100 to be disconnected when receiving the power-on instruction.

[0050] It should be noted that in a multi-split air conditioning system, the master 200 is usually an outdoor unit for unified heat exchange with the outside world, and the slave 100 is an indoor unit for heat exchange with indoor air. The condenser of each indoor unit is connected to the master 200 through a pipeline for refrigerant transmission and is controlled by an electrically controlled valve to open and close the condenser inlet. When the slave 100 is powered off due to external factors or abnormal switching power supply, the electrically controlled valve is not powered off, the pipeline continues to transmit refrigerant to the condenser, and at the same time, the fan of the indoor unit stops due to power loss, resulting in the accumulation of cold air around the condenser in the slave 100.

[0051] In the embodiment, the initial running state of the slave 100 and the master 200 is a communication state, in which the plurality of slaves 100 respectively communicate with the master 200 through a bus to transmit data such as load information and environmental information. The slave 100 acquires power supply information of an external power source in real time when working, and the power supply information can include input voltage, input current, or input power. When it is detected that the external power source is 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 a preset low voltage value or the input current is lower than a preset undercurrent value. At this time, the slave 100 outputs power-on request information with the address of the slave 100 to the master 200 through the bus.

[0052] The master 200 determines a target slave according to the address in the power-on request information when receiving the power-on request information. At this time, the master 200 determines other slaves 100 as non-target slaves 100 except for the target slave 100, and outputs a power-on instruction to at least one non-target slave 100 through the bus.

[0053] When any slave 100 receives the power supply instruction, the slave 100 switches its current operation mode to the power supply mode. It can be understood that the power supply mode is realized by the internal circuit of the slave 100, which connects the bus to the external power supply connected to the slave 100, so that the bus is changed from transmitting communication data to transmitting external power supply. Thus, by using the principle of current transmission from high potential to low potential, the external power supply in the bus is output to the slave 100 that loses power, so that it drives the electromagnetic valve to close by using the power output by the bus, thereby avoiding the continuous transmission of refrigerant.

[0054] The technical scheme of the present application uses the scheme of connecting through the bus in the multi-connected air conditioning system, and time-multiplexes the bus, so that when the power supply information obtained by any slave 100 includes power failure information, the slave 100 can output a power supply request to the master 200, and the master 200 controls other slaves 100 to connect the external power supply connected to each slave 100 to the bus to supply power to the slave 100 and drive the electromagnetic valve to close, thereby reducing the situation that the indoor unit loses power due to external factors or abnormality of the indoor unit switch power supply, and the electromagnetic valve remains open to connect the refrigerant, causing the evaporator of the indoor unit to frost, and even the air conditioning system to work abnormally.

[0055] Further, in addition to controlling the non-target slave to supply power to the target slave, the master 200 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.

[0056] Reference Figure 1 and Figure 7 In an embodiment, the non-target slave is also used to time after switching to the power supply mode, and switch from the power supply mode to the communication mode when the first preset time is reached.

[0057] It can be understood that the non-target slave sets the power supply mode only to drive the target slave to close the electromagnetic valve, and if the power supply is continued, it will affect the communication between the non-target slave and the master 200, causing the master 200 to be unable to obtain the working condition of the non-target slave in time.

[0058] Since the non-target slave cannot communicate with the master 200 or other slaves 100 in the power supply mode, it cannot determine when to re-establish communication, therefore, in this embodiment, a first preset time is set in the slave 100, which should be a redundant value based on the normal operation time of the electromagnetic 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, the first preset time is started, and the communication mode is switched after the timing is ended, so as to communicate with the master 200 in time and transmit the current working data.

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

[0060] In this embodiment, the second preset time is also taken as a redundant value according to the conventional action time of the electromagnetic valve, and the second preset time can be the same as or different from the first preset time.

[0061] After the host 200 switches to the power supply mode, the second preset time is started, and after the timing ends, the communication mode is switched to the communication mode, and the communication normal information is broadcast to the bus, so as to restore the normal communication state of the bus in time.

[0062] Referring to Figure 1 and Figure 7 In an embodiment, the target slave is further configured to switch from the communication mode to the power receiving mode when the power down information is obtained, and switch from the power receiving mode to the communication mode after the electromagnetic valve is disconnected.

[0063] In this embodiment, the power receiving mode is the same as the power supply mode described above. By the action of the internal circuit of the slave 100, the bus is connected to the power supply end inside the slave 100, so that the output of the external power supply of the other slave 100 or the host 200 connected to the bus is output to the inside of the slave 100, and the slave 100 is driven to work, and the electromagnetic valve is driven to close.

[0064] At the same time, in order to avoid the target slave still maintaining the power receiving mode after the power supply of the power grid is restored, the connected external power supply is input to the bus, which affects the normal communication of the host 200 and other slaves 100. The target slave is configured to switch from the power receiving mode to the communication mode after the electromagnetic valve is disconnected, and the third preset time is timed. The third preset time can be a redundant time of 10s, 15s, etc.

[0065] Referring to Figure 2 In an embodiment, the slave 100 comprises:

[0066] The power supply interface 111 is connected to the ground interface 112, the power supply interface 111 is used to connect the external power supply, and the ground interface 112 is grounded.

[0067] The selection circuit 120 comprises a first channel 121 and a second channel 122, the input ends of the first channel 121 and the second channel 122 are connected to the bus respectively, and the two output ends of the first channel 121 are connected to the power supply interface 111 and the ground interface 112 respectively.

[0068] The control circuit 130 comprises a control terminal and two communication terminals, the two communication terminals are connected to the two output terminals of the second channel 122 respectively, the control terminal is connected to the controlled terminal of the selection circuit 120, and the control circuit 130 is used for controlling the first channel 121 and the second channel 122 to switch on.

[0069] In the embodiment, the power interface 111 can access the switching power supply, BMS (power management circuit) and the like in the internal machine, and access the external power supply output as the power supply of the host 200.

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

[0071] The ground interface 112 is used for forming a current loop with the power interface 111 when the first channel 121 is on.

[0072] Referring to Figure 2 , Figure 5 and Figure 6 , in an embodiment, the bus comprises a power line and a ground line, and the selection circuit 120 comprises:

[0073] A first switch S1, an input terminal of the first switch S1 is used for accessing the power line, a first output terminal of the first switch S1 accesses the power interface 111, and a second output terminal of the first switch S1 accesses a communication terminal of the control circuit 130;

[0074] A second switch S2, an input terminal of the second switch S2 is used for accessing the ground line, a first output terminal of the second switch S2 accesses the ground interface 112, and a second output terminal of the second switch S2 accesses another communication terminal of the control circuit 130;

[0075] A coil L1, a first end of the coil L1 is used for accessing the power line;

[0076] a light coupling U1, a first end of a light emitting side of which is connected to the first power supply, a second end of the light emitting side of which is electrically connected to the control circuit 130, a first end of a receiving side of which is connected to the ground, and a second end of the receiving side of which is connected to the second end of the coil L1.

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

[0078] When the slave 100 is in normal operation, the control circuit 130 collects the power supply information at the power supply interface 111 in real time. When the collected power supply information does not include power-off information, the control circuit 130 outputs an off control signal to the light coupling U1, so as to keep the light coupling U1 off. At this time, the current loop in which the coil L1 is located is disconnected, and the first switch S1 and the second switch S2 are not actuated. When the collected power supply information includes power-off information, the control circuit 130 outputs a conductive control signal to the light coupling U1, so as to control the light coupling U1 to be conductive. At this time, the current loop in which the coil L1 is located is connected, and the first switch S1 and the second switch S2 are actuated under the action of the coil L1, so as to connect the corresponding first output end and the input end.

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

[0080] Referring to Figure 3 and Figure 5 In an embodiment, the control circuit 130 comprises:

[0081] a communication circuit 131 comprising a first differential end, a second differential end, a first sending end and a first receiving end, the first differential end and the second differential end being two communication ends of the control circuit 130;

[0082] a processor 132 comprising a detection end, a second sending end and a second receiving end, the second sending end being connected to the first receiving end, and the second receiving end being connected to the first sending end;

[0083] a sampling circuit 133 connected in series between the power supply interface 111 and the detection end, the sampling circuit 133 being configured to collect a power supply parameter of the external power supply;

[0084] the processor 132 is configured 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 the embodiment, the communication circuit 131 can include a 485 communication chip, which is used to convert bus communication and 485 communication of the processor 132.

[0086] When the slave 100 is powered on, the sampling circuit 133 collects the external power source accessed through the power supply interface 111. Specifically, the sampling circuit 133 can include a voltage dividing circuit formed by a sampling resistor R1 and at least one voltage dividing resistor R2 in series. The voltage change between the two ends of the sampling resistor R1 reflects the power supply parameters of the external power source, such as output voltage or output current, etc.

[0087] Therefore, when the processor 132 detects that the power supply information includes power-off information according to the power supply parameters, the processor 132 outputs the power-on request information through the communication circuit 131, or when the power supply information does not include power-off information and the power-on instruction is accessed through the communication circuit 131, the processor 132 controls the selection circuit 120 to switch the channel.

[0088] Referring to Figure 3 and Figure 5 In an embodiment, the control circuit 130 further includes:

[0089] a delay circuit 134 connected in parallel between the power supply end of the processor 132 and the ground end of the processor 132. The delay circuit 134 is used to output stored electrical energy to the processor 132 when the external power source stops being accessed.

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

[0091] In the embodiment, the delay circuit 134 can include a capacitor. Since the capacitor is connected to the power supply end of the processor 132, the capacitor can store the accessed electrical energy when the external power source is not powered off. Therefore, when the external power source is powered off, the capacitor discharges to supply power to the processor 132, so as to prolong the working time of the processor 132 after power-off.

[0092] It can be understood that the delay time obtained by the processor 132 is related to the electrical energy storage capacity of the capacitor. The capacity of the capacitor is designed to be able to send a power-on request signal to the bus while having a certain redundant time to wait for the bus to be idle after the processor 132 is powered off. The theoretical capacity can be calculated according to the charge amount formula Q=I*t and the capacitor capacity formula , that is: wherein Q is the charge amount, I is the current flowing through the capacitor, t is the delay time, C is the capacity of the capacitor, and U is the voltage between the two ends of the capacitor.

[0093] Thus, after the external power supply is powered off, the control circuit 130 can perform delayed power-off through the delay circuit 134, and perform signal transmission and bus state information collection. The bus state information can be determined according to whether data transmission exists in the bus or whether the level of the bus output is the level representing the idle state. When it is detected that no data transmission exists in the bus or the level of the bus output is the level representing the idle state, it is determined that the collected bus state information is the bus idle information.

[0094] Referring to Figure 4 and Figure 5 In an embodiment, the slave 100 further comprises:

[0095] The power supply management circuit 140 is connected to the power supply interface 111, and the output ends of the power supply management circuit 140 are connected to the power supply ends of the control circuit 130 and the selection circuit 120, respectively. The power supply management circuit 140 is used to convert the voltage of the external power supply and supply power to the control circuit 130 and the selection circuit 120.

[0096] In the embodiment, the power supply management circuit 140 is connected to the power supply interface 111. When the area power grid where the slave 100 is located is normally powered, the external power supply of the area is connected through the power supply interface 111. When the slave 100 is powered off and powered by the bus by other slaves 100 and the master 200, the external power supply of other areas transmitted by the bus is connected. After the external power supply is connected, the voltage of the external power supply is converted, and the power supply matching the control circuit 130 and the selection circuit 120 is output.

[0097] Specifically, the power supply management circuit 140 can include a voltage reduction chip and a plurality of capacitors. The input end and the output end of the voltage reduction chip are connected to the ground through the capacitors, respectively, for voltage stabilization of the power supply connected to or output by the voltage reduction chip. The input end of the voltage reduction chip can be further provided with a PTC (thermistor) circuit to avoid the impact of large current on the voltage reduction chip during power-on.

[0098] The above description is only an optional embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation made according to the content of the present application specification and drawings, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. An air conditioning system, characterized by, The application relates to a power supply system, which comprises: a plurality of slave machines, each of which is used for acquiring corresponding power supply information and outputting power supply request information when the power supply information comprises power-off information; a master machine which is electrically connected with the plurality of slave machines through a bus, and is used for determining a target slave machine when the power supply request information is received, determining other slave machines as non-target slave machines except for the target slave machine, and sending power supply instructions to the non-target slave machines; the non-target slave machine is used for switching from a communication mode to a power supply mode to supply power to the target slave machine and drive an electromagnetic valve of the target slave machine to be disconnected when the power supply instructions are received; the slave machine comprises: a power supply interface and a ground interface, the power supply interface is used for accessing an external power supply, and the ground interface is grounded; a selection circuit which comprises a first channel and a second channel, input ends of the first channel and the second channel are respectively connected with the bus, and two output ends of the first channel are respectively connected with the power supply interface and the ground interface; a control circuit which comprises a control end and two communication ends, the two communication ends are respectively connected with two output ends of the second channel in one-to-one correspondence, the control end is connected with a controlled end of the selection circuit, and the control circuit is used for controlling the first channel and the second channel to switch on; the bus comprises a power supply line and a ground line, and the selection circuit comprises: a first switch, an input end of the first switch is used for accessing the power supply line, a first output end of the first switch is connected with the power supply interface, and a second output end of the first switch is connected with a communication end of the control circuit; a second switch, an input end of the second switch is used for accessing the ground line, a first output end of the second switch is connected with the ground interface, and a second output end of the second switch is connected with another communication end of the control circuit; a coil, a first end of the coil is used for accessing the power supply line; an optical coupler, a first end of a light-emitting side of the optical coupler is connected with a first power supply, a second end of the light-emitting side of the optical coupler is electrically connected with the control circuit, a first end of a receiving side of the optical coupler is connected with the ground line, and a second end of the receiving side of the optical coupler is connected with a second end of the coil.

2. The air conditioning system of claim 1, wherein, the non-target slave machine is further used for timing after switching to the power supply mode, and switching from the power supply mode to the communication mode when the timing reaches a first preset time.

3. The air conditioning system of claim 1, wherein, the master machine is further used for switching from the communication mode to the power supply mode to supply power to the target slave machine after outputting the power supply instructions.

4. The air conditioning system of claim 3, wherein, the master machine is further used for timing after switching to the power supply mode, and switching from the power supply mode to the communication mode when the timing reaches a second preset time.

5. The air conditioning system according to any one of claims 1 to 4, wherein the target slave machine is further used for switching from the communication mode to a power receiving mode when the power-off information is acquired, and switching from the power receiving mode to the communication mode after the electromagnetic valve is disconnected.

6. The air conditioning system of claim 1, wherein, the control circuit comprises: a communication circuit which comprises a first differential end, a second differential end, a first sending end and a first receiving end, the first differential end and the second differential end are the two communication ends of the control circuit; a processor which comprises a detection end, a second sending end and a second receiving end, the second sending end is connected with the first receiving end, and the second receiving end is connected with the first sending end. A sampling circuit is connected in series between the power interface and the detection terminal, and is configured to collect the power parameter of the external power supply; The processor is configured to communicate with the host through the communication circuit, and determine the power supply information according to the received power parameter.

7. The air conditioning system of claim 6, wherein, The control circuit further comprises: A delay circuit is connected in parallel between the power terminal of the processor and the ground terminal of the processor, and is configured to output the stored electric energy to the processor when the external power supply stops being connected. The processor is further configured to, after outputting the power supply request information, control the first channel to be connected within a delay time according to the obtained bus idle information, so as to connect the external power supply output by the bus.

8. The air conditioning system of claim 1, wherein, The slave further comprises: A power supply management circuit, an input end of which is connected to the power interface, and output ends of which are connected to the power terminal of the control circuit and the power terminal of the selection circuit respectively, and is configured to supply power to the control circuit and the selection circuit after voltage conversion processing of the external power supply.

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