air conditioning system

Abstract

A direct-current power source (110, 210) generates a power source voltage that is a direct current voltage. A communication circuit (130, 230) is driven by means of the power source voltage generated by the direct-current power source (110, 210). The communication circuit (130, 230) communicates via communication lines with another communication circuit (130, 230) using a communication scheme that employs a high frequency signal. The communication lines are core wires (301, 302) included in a cable (300) having a shield (303). At both ends of the cable (300), the shield (303) is connected to a ground of the communication circuit (130, 230).

Description

[Technical Field]

[0001] The present disclosure relates to air conditioning systems. [Background technology]

[0002] In recent years, communication traffic within air conditioning systems has tended to increase with the advancement of control content and improvements in analytical technology using sensing data. In order to deal with this increase in communication traffic, consideration is being given to changing the communication method between air conditioning devices to one that enables high-speed communication. For example, Patent Document 1 describes an air conditioning system in which indoor and outdoor units communicate using a communication method compatible with Orthogonal Frequency Division Multiplexing (OFDM).

[0003] Incidentally, when the communication lines of one air conditioning system run parallel to the communication lines of another air conditioning system, crosstalk can occur due to capacitive coupling caused by stray capacitance between the communication lines, inductive coupling caused by mutual inductance, etc. When crosstalk occurs, information sent from one air conditioning device can be mistakenly transmitted to an air conditioning device that is not the intended recipient. Such crosstalk is more likely to occur the higher the frequency of the signals used for communication. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-152426 Summary of the Invention [Problem to be solved by the invention]

[0005] However, Patent Document 1 does not describe a method for suppressing such crosstalk. In other words, in the air conditioning system described in Patent Document 1, crosstalk may occur when air conditioning devices communicate using high-frequency signals. Therefore, there is a demand for technology that suppresses the occurrence of crosstalk when air conditioning devices communicate using high-frequency signals.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide an air conditioning system that suppresses the occurrence of crosstalk when communicating between air conditioning devices using high-frequency signals. [Means for solving the problem]

[0007] In order to achieve the above object, the air conditioning system according to the present disclosure comprises: An air conditioning system comprising a plurality of air conditioning devices and a communication line connecting the plurality of air conditioning devices to each other, the communication line is a core wire included in a cable equipped with a shield, The plurality of air conditioning devices a DC power supply that generates a power supply voltage that is a DC voltage; a communication circuit driven by the power supply voltage generated by the DC power supply; a terminal block for connecting the communication line to the communication circuit; a metal housing that houses the terminal block and a portion of the cable where the core wire is not covered by the shield; Equipped with the communication circuit communicates with another communication circuit via the communication line using a communication method that uses a high-frequency signal; before At both ends of the cable, the shield is connected to the ground of the communication circuit. And, The metal housing does not have an opening longer than a length threshold corresponding to the wavelength of the high-frequency signal. . [Effects of the Invention]

[0008] In the present disclosure, the communication lines connecting multiple air conditioners to each other are core wires included in a cable with a shield, and the shields are connected to the ground of the communication circuit at both ends of the cable. Therefore, according to the present disclosure, it is possible to suppress the occurrence of crosstalk when communicating between air conditioners using high-frequency signals. [Brief explanation of the drawings]

[0009] [Figure 1] Configuration diagram of an air conditioning system according to embodiment 1 [Figure 2] Configuration diagram of an outdoor unit according to the first embodiment [Figure 3] An explanatory diagram of connections between devices included in a refrigerant system according to the first embodiment. [Figure 4] Cable connection diagram [Figure 5] An illustration of how crosstalk is suppressed [Figure 6] An explanatory diagram of connections between devices included in a refrigerant system according to a second embodiment. [Figure 7] Configuration diagram of a DC power supply according to a third embodiment [Figure 8] Configuration diagram of a DC power supply according to a fourth embodiment DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals.

[0011] (Embodiment 1) FIG. 1 is a diagram showing the configuration of an air conditioning system 2000 according to the first embodiment. The air conditioning system 2000 is a system for conditioning the air inside a building, condominium, apartment, factory, or the like. The air conditioning system 2000 includes a plurality of refrigerant systems 1000 and a transmission line 40 that interconnects the plurality of refrigerant systems 1000. The number of refrigerant systems 1000 included in the air conditioning system 2000 can be adjusted as appropriate. In this embodiment, the air conditioning system 2000 includes at least two refrigerant systems 1000, namely, a refrigerant system 1000A and a refrigerant system 1000B. Note that the refrigerant systems 1000A and 1000B will be collectively referred to as the refrigerant system 1000 as appropriate.

[0012] The transmission path 40 is a transmission path capable of high-speed baseband communication, for example, a transmission path compatible with Ethernet (registered trademark). The transmission path 40 interconnects the outdoor units 100 equipped with a plurality of refrigerant systems 1000. The communication speed of the baseband communication using the transmission path 40 is, for example, 100 Mbps. A LAN (Local Area Network) is constructed by the transmission path 40.

[0013] The refrigerant system 1000 is a unit that conditions indoor air. The refrigerant system 1000 includes an outdoor unit 100, at least one indoor unit 200, and a transmission path 30 that interconnects the outdoor unit 100 and the at least one indoor unit 200. The number of indoor units 200 can be adjusted as appropriate. In this embodiment, the refrigerant system 1000A includes an outdoor unit 100A, an indoor unit 200A, and a transmission path 30A. The refrigerant system 1000B includes an outdoor unit 100B, an indoor unit 200B, and a transmission path 30B.

[0014] Air conditioners belonging to the same refrigerant system 1000 are connected to each other by refrigerant piping (not shown), allowing for the exchange of refrigerant. Air conditioners belonging to the same refrigerant system 1000 are also connected to each other by transmission path 30, allowing for communication. Outdoor unit 100A and outdoor unit 100B are collectively referred to as outdoor unit 100, as appropriate. Indoor unit 200A and indoor unit 200B are collectively referred to as indoor unit 200, as appropriate. Outdoor unit 100 and indoor unit 200 are collectively referred to as air conditioners, as appropriate. Transmission path 30A and transmission path 30B are collectively referred to as transmission path 30, as appropriate.

[0015] The outdoor unit 100 is a piece of equipment that conditions indoor air and is installed outdoors. Conditioning indoor air means adjusting the temperature, humidity, air cleanliness, etc. of the indoor air. The outdoor unit 100 communicates with at least one indoor unit 200 via a transmission path 30. The outdoor unit 100 circulates refrigerant between the outdoor unit 100 and at least one indoor unit 200 via refrigerant piping (not shown). The outdoor unit 100 is an example of an air conditioning device.

[0016] The configuration of the outdoor unit 100 will be described with reference to Fig. 2. Fig. 2 mainly shows only the configuration related to communication among the configuration of the outdoor unit 100. As shown in Fig. 2, the outdoor unit 100 includes a control unit 11, a storage unit 12, a first communication unit 13, and a second communication unit 14.

[0017] The control unit 11 includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), RTC (Real Time Clock), etc. The CPU is also called a central processing unit, central arithmetic unit, processor, microprocessor, microcomputer, DSP (Digital Signal Processor), etc., and functions as a central arithmetic processing unit that executes processes and calculations related to the control of the outdoor unit 100. In the control unit 11, the CPU reads out programs and data stored in the ROM and uses the RAM as a work area to perform overall control of the outdoor unit 100. The RTC is, for example, an integrated circuit with a timekeeping function. The CPU can determine the current date and time from the time information read out from the RTC.

[0018] The storage unit 12 includes a nonvolatile semiconductor memory such as a flash memory, an EPROM (Erasable Programmable ROM), or an EEPROM (Electrically Erasable Programmable ROM), and serves as a so-called auxiliary storage device. The storage unit 12 stores programs and data used by the control unit 11 to execute various processes. The storage unit 12 also stores data generated or acquired by the control unit 11 as a result of executing various processes.

[0019] The first communication unit 13 communicates with other outdoor units 100 via the transmission path 40 in accordance with the control of the control unit 11. The first communication unit 13 includes a communication interface for connecting to the transmission path 40. The first communication unit 13 includes, for example, a LAN card compatible with Ethernet (registered trademark).

[0020] The second communication unit 14 communicates with at least one indoor unit 200 via the transmission path 30 under the control of the control unit 11. The second communication unit 14 communicates with the indoor unit 200 via the transmission path 30 using a communication method that uses high-frequency signals. For example, the second communication unit 14 communicates with the indoor unit 200 using a multicarrier transmission method. The multicarrier transmission method is a transmission method in which signals are superimposed on subcarriers having multiple frequency spectra that do not interfere with each other. A typical multicarrier transmission method is the Orthogonal Frequency Division Multiplexing (OFDM) method. The frequency of the high-frequency signal is preferably 1 MHz or higher. In this embodiment, the frequency of the high-frequency signal is several MHz to several tens of MHz. The second communication unit 14 has a communication interface for connecting to the transmission path 30.

[0021] The indoor unit 200 is a piece of equipment that conditions indoor air and is installed indoors. The indoor unit 200 blows out conditioned air into the room. The conditioned air is air for conditioning the air in the room, and is basically heated air or cooled air. The heated air is air for heating the room and has a temperature higher than the temperature of the air in the room. The cooled air is air for cooling the room and has a temperature lower than the temperature of the air in the room.

[0022] The indoor unit 200 includes a control unit (not shown), a memory unit (not shown), and a communication unit (not shown). The control unit is basically configured in the same way as the control unit 11. The memory unit is basically configured in the same way as the memory unit 12. The communication unit is basically configured in the same way as the second communication unit 14. The indoor unit 200 is an example of an air conditioning device.

[0023] The transmission path 30 is a transmission path that interconnects the outdoor unit 100 and at least one indoor unit 200 within one refrigerant system 1000. The transmission path 30 includes a communication line for communication between the outdoor unit 100 and the indoor unit 200. When the refrigerant system 1000 includes multiple indoor units 200, for example, the transmission path 30 connects the multiple indoor units 200 in parallel to the outdoor unit 100.

[0024] If the transmission path 30A of the refrigerant system 1000A and the transmission path 30B of the refrigerant system 1000B are arranged in close proximity to each other in parallel, crosstalk may occur, in which a signal propagates from one transmission path 30A to the other. The higher the frequency of the high-frequency signal used for communication, the more likely crosstalk occurs. The main causes of crosstalk include capacitive coupling due to stray capacitance, inductive coupling due to mutual inductance, and radio wave radiation. If crosstalk occurs during the network configuration recognition process, the network configuration may be erroneously recognized.

[0025] For example, in the recognition process in the refrigerant system 1000A, the outdoor unit 100A confirms that the indoor unit 200A belongs to the refrigerant system 1000A. In this case, the outdoor unit 100A broadcasts a recognition signal to the transmission path 30A. In response to receiving the recognition signal, the indoor unit 200A transmits a response signal including its own address to the outdoor unit 100A via the transmission path 30A. The outdoor unit 100A considers that the indoor unit 200A that transmitted the response signal belongs to the refrigerant system 1000A.

[0026] Here, for example, assume that a recognition signal is transmitted to the indoor unit 200B via the transmission paths 30A and 30B due to crosstalk. In this case, the indoor unit 200B outputs a response signal including its own address to the transmission path 30B. Then, due to crosstalk, this response signal may be transmitted to the outdoor unit 100A via the transmission paths 30B and 30A. In this case, the outdoor unit 100A erroneously recognizes that the indoor unit 200B that returned the response signal belongs to the refrigerant system 1000A.

[0027] Therefore, in this embodiment, the occurrence of crosstalk is suppressed by using a shielded cable as the transmission line 30. Hereinafter, the connections between the devices in the refrigerant system 1000 will be described with reference to FIG.

[0028] The outdoor unit 100 includes a DC power supply 110, a control circuit 120, a communication circuit 130, a terminal block 140, and a metal housing 150. The indoor unit 200 includes a DC power supply 210, a control circuit 220, a communication circuit 230, a terminal block 240, and a metal housing 250. The outdoor unit 100 and the indoor unit 200 are connected to each other by a cable 300. The outdoor unit 100 and the indoor unit 200 receive power from an external power supply 400. In this embodiment, the external power supply 400 is a commercial power supply that supplies single-phase 200V AC power. The external power supply 400 is an example of an external power supply.

[0029] The DC power supply 110 generates a DC voltage, which is a power supply voltage, from power supplied from the external power supply 400. This power supply voltage is used to drive the control circuit 120 and the communication circuit 130. In FIG. 3, this power supply voltage is indicated as DC (Direct Current). The DC power supply 110 applies the generated power supply voltage between a power supply terminal 111 and a ground terminal 112. The power supply terminal 111 is a terminal to which the power supply voltage generated by the DC power supply 110 is applied. The ground terminal 112 is a terminal set to a ground potential, which is a potential that serves as a reference for circuit operation.

[0030] The DC power supply 110 converts AC power supplied from the external power supply 400 into DC power and outputs a power supply voltage. The DC power supply 110 includes an AC (Alternating Current) / DC converter (not shown) for converting AC to DC. This AC / DC converter (not shown) includes, for example, a diode bridge rectifier (not shown), an input capacitor (not shown), a switching element (not shown), a control circuit (not shown), a high-speed rectifying diode (not shown), and an output capacitor (not shown). The DC power supply 110 is an example of a DC power supply.

[0031] The control circuit 120 controls the communication circuit 130 to execute various processes related to communication. For example, the control circuit 120 generates a communication command to be transmitted by the communication circuit 130 to the indoor unit 200, and supplies the generated communication command to the communication circuit 130. The control circuit 120 also acquires a communication command received by the communication circuit 130 from the indoor unit 200, and analyzes the acquired communication command. The control circuit 120 operates on a power supply voltage generated by the DC power supply 110. That is, the control circuit 120 is connected to a power supply terminal 111 and a ground terminal 112, and operates on the power supply voltage applied between the power supply terminal 111 and the ground terminal 112. The control circuit 120 includes a CPU (not shown), a ROM (not shown), a RAM (not shown), etc. The control circuit 120 corresponds to the control unit 11.

[0032] The communication circuit 130 communicates with the indoor unit 200 under the control of the control circuit 120. For example, the communication circuit 130 transmits a communication command generated by the control circuit 120 to the indoor unit 200 via the cable 300. For example, the communication circuit 130 modulates a carrier wave with a baseband signal corresponding to the communication command to be transmitted, and applies the high-frequency signal obtained by the modulation between the two core wires of the cable 300. This high-frequency signal is a differential signal applied between the two core wires. The frequencies of the carrier wave and the high-frequency signal are preferably 1 MHz or higher. In this embodiment, the frequencies of the carrier wave and the high-frequency signal are several MHz to several tens of MHz.

[0033] Furthermore, the communication circuit 130 receives communication commands from the indoor unit 200 via the cable 300 and supplies the received communication commands to the control circuit 120. For example, the communication circuit 130 demodulates a high-frequency signal applied between two core wires of the cable 300 and acquires a baseband signal corresponding to the received communication command.

[0034] The communication circuit 130 operates on the power supply voltage generated by the DC power supply 110. That is, the communication circuit 130 is connected to a power supply terminal 111 and a ground terminal 112, and operates on the power supply voltage applied between the power supply terminal 111 and the ground terminal 112. The communication circuit 130 includes a communication driver IC (Integrated Circuit), a communication interface represented by a pulse transformer, and the like. The communication circuit 130 corresponds to the second communication unit 14. The communication circuit 130 is an example of a communication circuit.

[0035] Terminal block 140 is a terminal block for connecting cable 300, which is transmission path 30, to outdoor unit 100. Terminal block 140 includes terminals 141, 142, and 143. The configuration and connections of cable 300 will be described below with reference to FIG. 4.

[0036] Cable 300 is a cable used for power supply, communication, etc. Cable 300 is a shielded two-core cable, and includes core wire 301, core wire 302, shield 303, insulating member 311, insulating member 312, and insulating member 313. Core wire 301 and core wire 302 are electric wires for transmitting power, electrical signals, etc., and are made of, for example, copper, aluminum, etc.

[0037] The shield 303 covers and shields the core wire 301 and the core wire 302. In other words, the shield 303 prevents noise radiated from the external space from entering the core wire 301 and the core wire 302. The shield 303 also prevents noise from radiating from the core wire 301 and the core wire 302 to the external space. The shield 303 is made of, for example, copper, aluminum, or the like. The insulating member 311 is an insulator that covers the core wire 301. The insulating member 312 is an insulator that covers the core wire 302. The insulating member 313 is an insulator that covers the shield 303. The insulating members 311, 312, and 313 are made of, for example, vinyl chloride resin, or the like.

[0038] One end of core wire 301 is connected to terminal 141, which is connected to communication circuit 130. Therefore, one end of core wire 301 is connected to communication circuit 130. One end of core wire 302 is connected to terminal 142, which is connected to communication circuit 130. Therefore, one end of core wire 302 is connected to communication circuit 130. One end of shield 303 is connected to terminal 143, which is connected to ground terminal 112.

[0039] The other end of core wire 301 is connected to terminal 241, which is connected to communication circuit 230. Therefore, the other end of core wire 301 is connected to communication circuit 230. The other end of core wire 302 is connected to terminal 242, which is connected to communication circuit 230. Therefore, the other end of core wire 302 is connected to communication circuit 230. The other end of shield 303 is connected to terminal 243, which is connected to ground terminal 212.

[0040] In this way, the cable 300 is a shielded cable that includes core wires 301 and 302 used for communication between the outdoor unit 100 and the indoor unit 200, and a shield 303 that shields the core wires 301 and 302. The cable 300 is an MVVS cable, a CVVS cable, or the like. When there are multiple indoor units 200, the terminal blocks 240 provided on the multiple indoor units 200 are connected to each other by the cable 300.

[0041] Metal housing 150 is a housing made of metal. Metal housing 150 shields the circuits housed inside from the outside. Metal housing 150 houses control circuit 120, communication circuit 130, and terminal block 140. As shown in FIG. 4 , metal housing 150 also houses uncoated portion 321 at one end of cable 300. Uncoated portion 321 is a portion at one end of cable 300 where core wires 301 and 302 are not covered by shield 303.

[0042] The length of the openings in the metal housing 150 is sufficiently shorter than the wavelength of the high-frequency signal used for communication. In other words, the metal housing 150 does not have any openings longer than a length threshold corresponding to the wavelength of the high-frequency signal used for communication. The length threshold is preferably, for example, 1 / 100 or less of the wavelength of the high-frequency signal. The metal housing 150 has various openings for passing wiring connecting the inside and outside. The length of the longest part of each of these various openings is equal to or less than the length threshold.

[0043] For example, metal housing 150 has opening 151 for passing cable 300. The length of the longest part of opening 151 is equal to or less than the length threshold. In this way, metal housing 150 only has opening 151 whose length is sufficiently shorter than the wavelength of the high-frequency signal. Therefore, radio waves emitted from terminal block 140 and uncoated portion 321 in conjunction with the transmission of the high-frequency signal are blocked by metal housing 150. This suppresses the occurrence of crosstalk due to radio wave emission.

[0044] The DC power supply 210 generates a power supply voltage, which is a DC voltage, from power supplied from the external power supply 400. This power supply voltage is used to drive the control circuit 220 and the communication circuit 230. The DC power supply 210 applies the generated power supply voltage between a power supply terminal 211 and a ground terminal 212. The power supply terminal 211 is a terminal to which the power supply voltage generated by the DC power supply 210 is applied. The ground terminal 212 is a terminal set to a ground potential, which is a potential that serves as a reference for circuit operation. The DC power supply 210 basically has the same configuration as the DC power supply 110. The DC power supply 210 is an example of a DC power supply.

[0045] The control circuit 220 controls the communication circuit 230 to execute various processes related to communication. For example, the control circuit 220 generates a communication command to be transmitted by the communication circuit 230 to the outdoor unit 100, and supplies the generated communication command to the communication circuit 230. The control circuit 220 also acquires a communication command received by the communication circuit 230 from the outdoor unit 100, and analyzes the acquired communication command. The control circuit 220 operates on a power supply voltage generated by the DC power supply 210. In other words, the control circuit 220 is connected to a power supply terminal 211 and a ground terminal 212, and operates on a power supply voltage applied between the power supply terminal 211 and the ground terminal 212. The control circuit 220 basically has the same configuration as the control circuit 120.

[0046] The communication circuit 230 communicates with the outdoor unit 100 under the control of the control circuit 220. For example, the communication circuit 230 transmits a communication command generated by the control circuit 220 to the outdoor unit 100 via the cable 300. For example, the communication circuit 230 modulates a carrier wave with a baseband signal corresponding to the communication command to be transmitted, and applies the high-frequency signal obtained by the modulation between the two core wires of the cable 300.

[0047] Furthermore, the communication circuit 230 receives a communication command from the outdoor unit 100 via the cable 300, and supplies the received communication command to the control circuit 220. For example, the communication circuit 230 demodulates a high-frequency signal applied between two core wires of the cable 300, and acquires a baseband signal corresponding to the received communication command.

[0048] The communication circuit 230 operates on the power supply voltage generated by the DC power supply 210. That is, the communication circuit 230 is connected to a power supply terminal 211 and a ground terminal 212, and operates on the power supply voltage applied between the power supply terminal 211 and the ground terminal 212. The communication circuit 230 basically has the same configuration as the communication circuit 130. The communication circuit 230 is an example of a communication circuit.

[0049] The terminal block 240 is a terminal block for connecting the cable 300, which is the transmission path 30, to the indoor unit 200. The terminal block 240 includes a terminal 241, a terminal 242, and a terminal 243. As described above, the other end of the core wire 301 is connected to the communication circuit 230 via the terminal 241. The other end of the core wire 302 is connected to the communication circuit 230 via the terminal 242. The other end of the shield 303 is connected to the ground terminal 212 via the terminal 243.

[0050] Metal housing 250 is a housing made of metal. Metal housing 250 shields the circuits housed inside from the outside. Metal housing 250 houses control circuit 220, communication circuit 230, and terminal block 240. As shown in FIG. 4 , metal housing 250 also houses uncoated portion 322 at the other end of cable 300. Uncoated portion 322 is a portion at the other end of cable 300 where core wires 301 and 302 are not covered by shield 303.

[0051] Metal housing 250 does not have any openings longer than the length threshold. Metal housing 250 has various openings for passing wires connecting the inside and outside. The length of the longest part of these various openings is equal to or less than the length threshold. For example, metal housing 250 has opening 251 for passing cable 300. The length of the longest part of this opening 251 is equal to or less than the length threshold.

[0052] As described above, metal housing 250 has only opening 251 whose length is sufficiently shorter than the wavelength of the high-frequency signal. Therefore, radio waves emitted from terminal block 240 and uncoated portion 322 in association with the transmission of the high-frequency signal are blocked by metal housing 250. Therefore, the occurrence of crosstalk due to radio wave emission is suppressed.

[0053] Next, the reason why the occurrence of crosstalk is suppressed will be explained. Causes of crosstalk include capacitive coupling due to electrostatic induction based on stray capacitance, inductive coupling due to electromagnetic induction based on mutual inductance, and radio wave radiation. This stray capacitance is the stray capacitance between the core wire 301 or the core wire 302 and another core wire. Furthermore, this mutual inductance is the mutual inductance between the core wire 301 or the core wire 302 and another core wire. Note that the other core wire is a core wire included in the transmission path 30 provided in another refrigerant system 1000.

[0054] First, if core wire 301 and core wire 302 are not covered with shield 303, when a high-frequency signal is transmitted, electrostatic induction based on stray capacitance may cause capacitive coupling between core wire 301 or 302 and another core wire, resulting in the possibility of the high-frequency signal being transmitted from core wire 301 or 302 to the other core wire. At this time, electromagnetic induction based on mutual inductance may cause inductive coupling between core wire 301 or 302 and the other core wire, resulting in the high-frequency signal being transmitted from core wire 301 or 302 to the other core wire. At this time, radio wave radiation may cause the high-frequency signal to be transmitted from core wire 301 or 302 to the other core wire.

[0055] On the other hand, in this embodiment, core wire 301 and core wire 302 are covered by shield 303, and shield 303 is connected to the ground. Therefore, when a high-frequency signal is transmitted, shield 303, which functions as an electrostatic shield, blocks the electric field, thereby suppressing transmission of the high-frequency signal due to capacitive coupling. Also, when a high-frequency signal is transmitted, shield 303, which functions as an electromagnetic shield, blocks the magnetic field, thereby suppressing transmission of the high-frequency signal due to inductive coupling. Also, when a high-frequency signal is transmitted, shield 303, which functions as an electromagnetic shield, blocks radio waves, thereby suppressing transmission of the high-frequency signal due to radio wave radiation.

[0056] Hereinafter, with reference to FIG. 5, the reason why transmission of high-frequency signals due to inductive coupling is suppressed when the communication circuit 130 included in the outdoor unit 100 transmits high-frequency signals to the communication circuit 230 included in the indoor unit 200 will be described.

[0057] When communication circuit 130 transmits a high-frequency signal to communication circuit 230, transmission current It1 flows through core wire 301 from communication circuit 130 toward communication circuit 230. When transmission current It1 flows through core wire 301, noise current In1 is generated in a portion of shield 303 that faces core wire 301. This noise current In1 flows to the ground of communication circuit 130, which is connected to one end of shield 303.

[0058] Here, the direction of the transmission current It1 flowing through the core wire 301 is opposite to the direction of the noise current In1 flowing through the shield 303. Therefore, the magnetic fields generated by the transmission current It1 and the noise current In1 cancel each other out. This suppresses crosstalk due to inductive coupling between the transmission paths 30. For example, when the outdoor unit 100A transmits a high-frequency signal to the indoor unit 200A via the transmission path 30A, no strong magnetic field is generated in the space outside the transmission path 30A. This prevents inductive coupling between the transmission paths 30A and 30B, and prevents the high-frequency signal from propagating from the transmission path 30A to the transmission path 30B.

[0059] Furthermore, when communication circuit 130 transmits a high-frequency signal to communication circuit 230, transmission current It1 flows from communication circuit 130 toward communication circuit 230 in core wire 301, and transmission current It2 flows from communication circuit 230 toward communication circuit 130 in core wire 302. The same can be said about transmission current It2 as about transmission current It1. In other words, when transmission current It2 flows in core wire 301, noise current In2 is generated in a portion of shield 303 facing core wire 302. This noise current In2 flows to the ground of communication circuit 130 connected to one end of shield 303.

[0060] Here, the direction of the transmission current It2 flowing through the core wire 302 is opposite to the direction of the noise current In2 flowing through the shield 303. Therefore, the magnetic fields generated by the transmission current It2 and the noise current In2 cancel each other out, thereby suppressing crosstalk due to inductive coupling between the transmission lines 30.

[0061] The above has described the case where communication circuit 130 transmits a high-frequency signal to communication circuit 230, but the same applies to the case where communication circuit 230 transmits a high-frequency signal to communication circuit 130. In other words, a noise current generated by a transmission current passed from communication circuit 230 to communication circuit 130 flows to the ground of communication circuit 230, thereby suppressing crosstalk due to inductive coupling between transmission paths 30.

[0062] In this embodiment, the communication line connecting multiple air conditioning apparatuses to each other is core wires 301 and 302 included in cable 300 having shield 303, and shield 303 is connected to ground at both ends of cable 300. This suppresses electrostatic coupling and inductive coupling between transmission paths 30, and suppresses crosstalk to air conditioning apparatuses that are not connected to cable 300. In this way, according to this embodiment, it is possible to suppress the occurrence of crosstalk when communicating between air conditioning apparatuses using high-frequency signals.

[0063] In this embodiment, metal housing 150, which does not have an opening longer than the length threshold, houses terminal block 140 and uncoated portion 321 of cable 300, and metal housing 250, which does not have an opening longer than the length threshold, houses terminal block 240 and uncoated portion 322 of cable 300. According to this embodiment, it is possible to suppress the occurrence of crosstalk due to radio wave radiation from terminal block 140, terminal block 240, uncoated portion 321, and uncoated portion 322.

[0064] (Embodiment 2) In the first embodiment, an example was described in which one end of the shield 303 is directly connected to the ground of the communication circuit 130, and the other end of the shield 303 is directly connected to the ground of the communication circuit 230. In the present embodiment, an example will be described in which one end of the shield 303 is indirectly connected to the ground of the communication circuit 130, and the other end of the shield 303 is indirectly connected to the ground of the communication circuit 230. Hereinafter, descriptions of configurations and functions similar to those in the first embodiment will be omitted or simplified as appropriate.

[0065] 6, a refrigerant system 1001 according to this embodiment includes an outdoor unit 101, an indoor unit 201, and a cable 300 serving as a transmission path 30. The outdoor unit 101 includes a DC power supply 110, a control circuit 120, a communication circuit 130, a terminal block 140, a metal housing 150, and a capacitor 160. The indoor unit 201 includes a DC power supply 210, a control circuit 220, a communication circuit 230, a terminal block 240, a metal housing 250, and a capacitor 260.

[0066] In this embodiment as well, control circuit 120 and communication circuit 130 are connected to power supply terminal 111 and ground terminal 112, and operate on the power supply voltage applied between power supply terminal 111 and ground terminal 112. Control circuit 220 and communication circuit 230 are connected to power supply terminal 211 and ground terminal 212, and operate on the power supply voltage applied between power supply terminal 211 and ground terminal 212.

[0067] In this embodiment, shield 303 is grounded at both ends of cable 300. Specifically, one end of shield 303 is connected to terminal 143, which is grounded via metal casing 150, and is grounded. The other end of shield 303 is connected to terminal 243, which is grounded via metal casing 250, and is grounded. Note that if metal casings 150 and 250 are large in size, metal casings 150 and 250 may not be grounded, and metal casings 150 and 250 themselves may be considered to be earthed.

[0068] In this embodiment, the impedance at the frequency of the high-frequency signal between the grounds at both ends of the cable 300 is equal to or less than a predetermined impedance threshold. The impedance threshold is a value at which the signal or noise is not significantly attenuated. In other words, in this embodiment, the signal or noise having the above frequency can pass between the grounds without being significantly attenuated.

[0069] In this embodiment, in order to connect the ground and the ground with low impedance at the above frequency, the grounds are grounded at both ends of the cable 300 via capacitors having a capacitance equal to or greater than a capacitance threshold. Specifically, at one end of the cable 300, the ground of the communication circuit 130 is grounded via a capacitor 160 having a capacitance equal to or greater than a capacitance threshold. At the other end of the cable 300, the ground of the communication circuit 230 is grounded via a capacitor 260 having a capacitance equal to or greater than a capacitance threshold. The capacitance threshold is a threshold corresponding to the frequency of the above high-frequency signal. The lower the frequency of the above high-frequency signal, the larger the capacitance threshold. The capacitance threshold is, for example, 1000 pF.

[0070] In this embodiment, the impedance at the above frequency is low between one end of shield 303 and the ground of communication circuit 130. Therefore, a noise current generated by the transmission current that communication circuit 130 passes to communication circuit 230 flows to the ground of communication circuit 130, thereby suppressing capacitive coupling, inductive coupling, and crosstalk due to radio wave radiation.

[0071] Furthermore, the impedance at the above frequency between the other end of shield 303 and the ground of communication circuit 230 is low. Therefore, a noise current generated by the transmission current that communication circuit 230 passes to communication circuit 130 flows to the ground of communication circuit 230, thereby suppressing capacitive coupling, inductive coupling, and crosstalk due to radio wave radiation.

[0072] In this embodiment, the ground of communication circuit 130 is connected to the ground via capacitor 160, and the ground of communication circuit 230 is connected to the ground via capacitor 260. Capacitor 160 and capacitor 260 function as a Y capacitor. That is, capacitor 160 channels common mode noise generated in cable 300 to the ground so that the noise does not flow into communication circuit 130. Capacitor 260 channels common mode noise generated in cable 300 to the ground so that the noise does not flow into communication circuit 230.

[0073] As described above, in this embodiment, shield 303 is grounded at both ends of cable 300, and the impedance at the frequency of the high-frequency signal between the grounds at both ends of cable 300 is equal to or less than a predetermined impedance threshold. Therefore, according to this embodiment, it is possible to reduce common-mode noise and suppress crosstalk.

[0074] (Embodiment 3) In the first embodiment, an example was described in which the inflow of noise into other devices via the external power supply 400 was not taken into consideration. In the present embodiment, a method for suppressing the inflow of noise into other devices via the external power supply 400 will be described. This noise is noise associated with communication using high-frequency signals, and is, for example, noise generated on the transmission path 30. This noise is, for example, noise corresponding to the noise current In1, noise current In2, etc., flowing within the shield 303. Hereinafter, descriptions of the same configurations and functions as those in the first and second embodiments will be omitted or simplified as appropriate.

[0075] As shown in FIG. 7, a DC power supply 110A according to this embodiment includes a power supply terminal 111, a ground terminal 112, a terminal 113, a terminal 114, an AC / DC converter 115, and a filter circuit 500.

[0076] The power supply terminal 111 is a terminal to which the power supply voltage output by the DC power supply 110A is applied. The ground terminal 112 is a terminal to which the ground potential of the DC power supply 110A is applied. The terminal 113 is a terminal connected to one end of the external power supply 400. The terminal 114 is a terminal connected to the other end of the external power supply 400. The AC / DC converter 115 converts the AC power supplied from the external power supply 400 via the filter circuit 500 into DC power.

[0077] The filter circuit 500 is a circuit for removing high frequencies, and is disposed between the external power supply 400 and the output portion of the DC power supply 110A. The output portion of the DC power supply 110A corresponds to the power supply terminal 111 and the ground terminal 112. The filter circuit 500 suppresses propagation of high-frequency components from the external power supply 400 to the AC / DC converter 115, and suppresses propagation of high-frequency components from the AC / DC converter 115 to the external power supply 400. Therefore, the filter circuit 500 attenuates noise flowing from the transmission path 30 to the external power supply 400 via the AC / DC converter 115. The filter circuit 500 is an example of a filter circuit.

[0078] Filter circuit 500 includes terminals 511, 512, 513, 521, 522, 523, resistor 531, capacitor 532, common mode coil 540, capacitors 551, 552, and 553. Terminals 511 and 512 are input terminals. Terminals 521 and 522 are output terminals. Terminals 513 and 523 are terminals that are grounded via metal housing 150.

[0079] Resistor 531 is a discharge resistor connected between the lines. Capacitor 532 and capacitor 551 are capacitors connected between the lines and primarily function to attenuate normal mode noise. Capacitor 552 and capacitor 553 are capacitors connected between the lines and earth and function to attenuate common mode noise.

[0080] Common mode coil 540 is a coil in which copper wire is wound in phase around a core made of magnetic material, and the magnetic fluxes of the currents flowing through both coils cancel each other out, preventing saturation of the core and achieving large inductance. Common mode coil 540 includes coil 541 provided on one line and coil 542 provided on the other line.

[0081] In this embodiment, noise generated during communication using a high-frequency signal is attenuated when passing through filter circuit 500. Therefore, this embodiment suppresses noise from flowing into other devices via external power supply 400. The other devices are devices connected to external power supply 400 other than the target device, which is a device having DC power supply 110A. For example, if the target device is outdoor unit 100A, the other devices are outdoor unit 100B, indoor unit 200A, indoor unit 200B, etc.

[0082] (Fourth embodiment) In the third embodiment, an example was described in which filter circuit 500 is arranged closer to external power supply 400 than AC / DC converter 115. In the present embodiment, an example will be described in which AC / DC converter 115 is arranged closer to external power supply 400 than filter circuit 500. Hereinafter, descriptions of configurations and functions similar to those of the first to third embodiments will be omitted or simplified as appropriate.

[0083] 8, the DC power supply 110B according to this embodiment includes a power supply terminal 111, a ground terminal 112, a terminal 113, a terminal 114, an AC / DC converter 115, and a filter circuit 500. In the DC power supply 110B, the AC / DC converter 115 is arranged closer to the external power supply 400 than the filter circuit 500.

[0084] That is, AC / DC converter 115 is connected to terminals 113, 114, 511, and 512, converts AC power supplied via terminals 113 and 114 into DC power, and supplies the DC power obtained by the conversion to filter circuit 500 via terminals 511 and 512. Furthermore, terminal 521 of filter circuit 500 is connected to power supply terminal 111, and terminal 522 of filter circuit 500 is connected to ground terminal 112. Filter circuit 500 attenuates noise flowing from transmission path 30 to external power supply 400 via AC / DC converter 115.

[0085] In this embodiment, noise generated during communication using a high-frequency signal is attenuated when passing through filter circuit 500. Therefore, according to this embodiment, the inflow of noise to other devices via external power supply 400 is suppressed.

[0086] (Variation) Although the embodiments of the present disclosure have been described above, various modifications and applications are possible when implementing the present disclosure. It is optional which parts of the configurations, functions, and operations described in the above embodiments are adopted in the present disclosure. Furthermore, in addition to the above-described configurations, functions, and operations, further configurations, functions, and operations may also be adopted in the present disclosure. Furthermore, the configurations, functions, and operations described in the above-described embodiments can be freely combined.

[0087] In the first embodiment, an example has been described in which crosstalk is suppressed by connecting the shields 303 of the cables 300 to the ground in both the outdoor unit 100 and the indoor unit 200. When the refrigerant system 1000 includes multiple indoor units 200, crosstalk can be suppressed by connecting the shields 303 of the cables 300 to the ground in both of the multiple indoor units 200.

[0088] In the first embodiment, an example has been described in which the transmission path 30 is used only for communication. The transmission path 30 may be used for power supply in addition to communication. For example, the outdoor unit 100 may supply the power supply voltage generated by the DC power supply 110 to the indoor unit 200 via the core wires 301 and 302 of the cable 300. Alternatively, the indoor unit 200 may supply the power supply voltage generated by the DC power supply 210 to the outdoor unit 100 via the core wires 301 and 302.

[0089] In the first embodiment, an example has been described in which the outdoor unit 100 and the indoor unit 200 communicate using high-frequency signals corresponding to a multi-carrier transmission method. The outdoor unit 100 and the indoor unit 200 may communicate using high-frequency signals corresponding to a transmission method other than the multi-carrier transmission method.

[0090] In the first embodiment, an example has been described in which a foil-shaped shield is used as the shield 303 included in the cable 300. A mesh-shaped shield may be used as the shield 303 included in the cable 300. In this case, it is preferable that the mesh spacing be sufficiently shorter than the wavelength of the high-frequency signal. For example, it is preferable that the mesh spacing be equal to or less than the above-mentioned length threshold, for example, equal to or less than 1 / 100 of the wavelength of the high-frequency signal. In this case, leakage of electric fields, magnetic fields, and radio waves from gaps in the shield 303 is suppressed, and crosstalk due to capacitive coupling, inductive coupling, radio wave radiation, etc. is suppressed.

[0091] In the third and fourth embodiments, an example has been described in which the filter circuit 500 is provided inside the DC power supply 110A or the DC power supply 110B. The filter circuit 500 may be provided outside the DC power supply 110A or the DC power supply 110B. Furthermore, in the third and fourth embodiments, an example has been described in which the filter circuit 500 is provided at one end of the DC power supply 110A or the DC power supply 110B. The filter circuit 500 may be provided at both ends of the DC power supply 110A or the DC power supply 110B.

[0092] Furthermore, filter circuit 500 is not limited to the circuits described in Embodiments 3 and 4. For example, filter circuit 500 may include terminals 511, 512, 513, 521, 522, 523, and common mode coil 540, but may not include resistor 531, capacitor 532, capacitor 551, capacitor 552, or capacitor 553.

[0093] The present disclosure allows various embodiments and modifications without departing from the broad spirit and scope of the present disclosure. Furthermore, the above-described embodiments are intended to illustrate the present disclosure and do not limit the scope of the present disclosure. That is, the scope of the present disclosure is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and the meaning of equivalent disclosures are considered to be within the scope of the present disclosure. [Industrial Applicability]

[0094] The present disclosure is applicable to air conditioning systems equipped with outdoor units and indoor units. [Explanation of symbols]

[0095] 11 control unit, 12 memory unit, 13 first communication unit, 14 second communication unit, 30, 30A, 30B, 40 transmission path, 100, 100A, 100B, 101 outdoor unit, 110, 110A, 110B, 210 DC power supply, 111, 211 power terminal, 112, 212 ground terminal, 113, 114, 141, 142, 143, 241, 242, 243, 511, 512, 513, 521, 522, 523 terminal, 115 AC / DC converter, 120, 220 control circuit, 130, 230 communication circuit, 140, 240 terminal block, 150, 250 metal housing, 151, 251 Opening, 160, 260, 532, 551, 552, 553 Capacitor, 200, 200A, 200B, 201 Indoor unit, 300 Cable, 301, 302 Core wire, 303 Shield, 311, 312, 313 Insulating material, 321, 322 Uncoated part, 400 External power supply, 500 Filter circuit, 531 Resistor, 540 Common mode coil, 541, 542 Coil, 1000, 1000A, 1000B, 1001 Refrigerant system, 2000 Air conditioning system

Claims

1. An air conditioning system comprising a plurality of air conditioning devices and a communication line connecting the plurality of air conditioning devices to each other, the communication line is a core wire included in a cable equipped with a shield, The plurality of air conditioning devices a DC power supply that generates a power supply voltage that is a DC voltage; a communication circuit driven by the power supply voltage generated by the DC power supply; a terminal block for connecting the communication line to the communication circuit; a metal housing that houses the terminal block and a portion of the cable where the core wire is not covered by the shield, the communication circuit communicates with another communication circuit via the communication line using a communication method that uses a high-frequency signal; At both ends of the cable, the shield is connected to the ground of the communication circuit; the metal housing does not have an opening longer than a length threshold corresponding to the wavelength of the high frequency signal; Air conditioning system.

2. At both ends of the cable, the shield is grounded; At both ends of the cable, the impedance at the frequency of the high frequency signal between the ground of the communication circuit and earth is equal to or less than a predetermined impedance threshold. The air conditioning system of claim 1 .

3. At both ends of the cable, the ground of the communication circuit is grounded via a capacitor having a capacitance equal to or greater than a capacitance threshold corresponding to the frequency of the high-frequency signal. The air conditioning system according to claim 2 .

4. the DC power supply generates the power supply voltage from power supplied from an external power supply; The plurality of air conditioning devices each include a filter circuit between the external power supply and an output portion of the DC power supply for removing high frequency waves. The air conditioning system according to any one of claims 1 to 3.

5. The frequency of the high frequency signal is 1 MHz or more. The air conditioning system according to any one of claims 1 to 3.

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