Air conditioner

Abstract

To suppress leakage of a high frequency signal in an air conditioner.SOLUTION: An air conditioner includes: an indoor unit 12; an outdoor unit 11; a transmitting circuit 24 which is provided in the indoor unit 12 and transmits a high frequency signal; a receiving circuit 44 which is provided in the outdoor unit 11 and receives the high frequency signal from the indoor unit 12; power feed wiring Wt2 which connects the outdoor unit 11 and the indoor unit 12, and supplies electric power from the outdoor unit 11 to the indoor unit 12; a communication wiring Wt1 which connects the outdoor unit 11 and the indoor unit 12, includes a power wire L1 constituting a part of the power feed wiring Wt2, and transmits the high frequency signal from the transmitting circuit 24 to the receiving circuit 44; an attenuation device 33 which attenuates the high frequency signal transmitted from the transmitting circuit 24; and control sections 23, 43 which control an attenuation amount of the high frequency signal by the attenuation device 33.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to an air conditioner.

Background Art

[0002] Patent Document 1 below discloses an air conditioner in which an outdoor unit and an indoor unit are communicably connected. In this air conditioner, the outdoor unit is connected to a commercial power supply, and power is supplied from the outdoor unit to the indoor unit via a power supply wiring. A power line that forms part of this power supply wiring is also used as a communication wiring, and a high-frequency signal for communication transmitted between the outdoor unit and the indoor unit is superimposed.

[0003] When a power line is used as a communication wiring as described above, there is a risk that a high-frequency signal may leak to the commercial power supply side through the power line. Therefore, in the outdoor unit of Patent Document 1, a low-pass filter for reducing the high-frequency signal is provided in the wiring connected to the commercial power supply.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present disclosure is to provide a new technique for suppressing leakage of a high-frequency signal in an air conditioner.

Means for Solving the Problems

[0006] (1) The air conditioner of the present disclosure includes an indoor unit, an outdoor unit, a transmission circuit provided in the indoor unit for transmitting a high-frequency signal, a reception circuit provided in the outdoor unit for receiving the high-frequency signal from the indoor unit, A power supply wiring that connects the outdoor unit and the indoor unit and supplies power from the outdoor unit to the indoor unit, A communication wiring that connects the outdoor unit and the indoor unit, includes power lines that form part of the power supply wiring, and transmits a high-frequency signal from the transmission circuit to the reception circuit, An attenuation device that attenuates the high-frequency signal transmitted from the transmission circuit, A control unit that controls the attenuation amount of the high-frequency signal by the attenuation device.

[0007] The air conditioner having the above configuration can reduce the signal strength of the high-frequency signal from the transmission circuit to the reception circuit by controlling the attenuation amount of the high-frequency signal by the attenuation device, and suppress the leakage of the high-frequency signal from the outdoor unit to the commercial power supply side.

[0008] (2) In the air conditioner of (1) above, preferably, the control unit controls the attenuation amount by the attenuation device based on the attenuation amount of the high-frequency signal in the communication wiring. The high-frequency signal attenuates in the communication wiring, and the attenuation amount varies depending on the length of the communication wiring. According to the above configuration, when the communication wiring is short, the overall attenuation amount required to suppress the leakage of the high-frequency signal can be ensured by increasing the attenuation amount by the attenuation device. Conversely, when the communication wiring is long, the overall required attenuation amount can be ensured even if the attenuation amount by the attenuation device is decreased.

[0009] (3) In the air conditioner of (2) above, preferably, the control unit obtains the attenuation amount of the high-frequency signal in the communication wiring and determines the attenuation amount of the high-frequency signal by the attenuation device based on this attenuation amount. With such a configuration, control of the attenuation amount by the control unit can be realized.

[0010] (4) In the air conditioner of (3) above, preferably, the control unit acquires information regarding the communication quality of the communication wiring and obtains the attenuation amount of the high-frequency signal in the communication wiring based on this information. The communication quality of the communication wiring varies depending on the length of the communication wiring, similar to the attenuation amount. Therefore, there is a correlation between the communication quality of the communication wiring and the attenuation amount, and the attenuation amount can be obtained using information regarding the communication quality.

[0011] (5) In the air conditioner according to any one of (1) to (4) above, preferably, the attenuation device includes an attenuator whose attenuation amount can be adjusted under the control of the control unit. With such a configuration, the attenuation amount of the high-frequency signal can be controlled using an attenuation device with a simple structure.

[0012] (6) In the air conditioner according to any one of (1) to (4) above, preferably, the attenuation device includes a plurality of attenuators having a predetermined attenuation amount, and the control unit controls the attenuation amount by the attenuation device by changing the number or type of the attenuators connected to the communication wiring. With such a configuration, the attenuation amount can be easily controlled.

[0013] (7) In the air conditioner according to any one of (1) to (6) above, a second communication wiring for transmitting a high-frequency signal from the transmission circuit to another device through a path different from the communication wiring is provided. According to this configuration, the attenuation amount can be controlled by the attenuation device without affecting the communication between the transmission circuit and another device.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0015] Hereinafter, embodiments of an air conditioner will be described in detail with reference to the accompanying drawings. [First Embodiment] FIG. 1 is an overall configuration diagram of an air conditioner according to a first embodiment. The air conditioner 10 of the present embodiment includes an outdoor unit 11 installed outside a building such as a building, a store, or a house, and an indoor unit 12 installed inside the building. The air conditioner 10 shown in FIG. 1 includes one outdoor unit 11 and a plurality of indoor units 12. The outdoor unit 11 and the plurality of indoor units 12 are connected by a refrigerant pipe P, and refrigerant is circulated between the outdoor unit 11 and the indoor unit 12 through this refrigerant pipe P to perform cooling and heating inside the building.

[0016] The outdoor unit 11 is connected to a commercial power supply 100 by a power supply wiring Wa1, and power is supplied from the commercial power supply 100. The indoor unit 12 is connected to the outdoor unit 11 by a power supply wiring Wa2, and power is supplied from the commercial power supply 100 via the outdoor unit 11. The outdoor unit 11 and the indoor unit 12 are connected by a communication wiring Wt. The outdoor unit 11 and the indoor unit 12 are communicably connected via the communication wiring Wt.

[0017] The air conditioner 10 includes a centralized controller 13. The centralized controller 13 is communicably connected to the outdoor unit 11 and the indoor unit 12 via the communication wiring Wt. The centralized controller 13 is used for managing or operating the outdoor unit 11 and the indoor unit 12.

[0018] Figure 2 is a block diagram showing the configuration related to communication between the outdoor unit and the indoor unit of the air conditioner. (Configuration of the indoor unit) The indoor unit 12 includes a power receiving circuit 21. The power receiving circuit 21 receives power from the commercial power supply 100 via the power supply wiring Wa1, Wa2, and the wiring in the outdoor unit 11 connected to the power supply wiring Wa1, Wa2. The power receiving circuit 21 supplies power to the devices inside the indoor unit 12.

[0019] The indoor unit 12 includes a fan inverter 22, an MCU (Micro Control Unit) 23, a high-frequency transceiver circuit 24, a low-frequency receiving circuit 25, and a low-frequency transceiver circuit 26. These devices are driven by the power supplied from the power receiving circuit 21.

[0020] The indoor unit 12 includes an indoor fan and an indoor heat exchanger (not shown). The fan inverter 22 is an inverter for operating the indoor fan. The indoor fan generates an air flow passing through the indoor heat exchanger. The MCU 23 functions as a control unit for controlling the internal devices of the indoor unit 12.

[0021] The MCU 23 includes a processor and a memory. The processor of the MCU 23 is composed of a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), a gate array, or an FPGA (Field Programmable Gate Array), etc. The ASIC, or a programmable logic device such as a gate array or an FPGA, is configured to be able to execute the same processing as the control program.

[0022] The memory of the MCU 23 includes volatile memories such as SRAM (Static Random Access Memory) and DRAM (Dynamic Random Access Memory), and non-volatile memories such as flash memory, hard disk, and ROM (Read Only Memory). The control program, which is a computer program, and control data are stored in the non-volatile memory. The MCU 23 exhibits various functions when the processor executes the control program. For example, the MCU 23 exhibits a function of controlling the attenuation amount of the high-frequency signal by the attenuation device 33 described later.

[0023] The power receiving circuit 21 includes an impedance booster 27, a noise filter 28, a rectifier circuit 29, a smoothing circuit 30, and a switching power supply 31. The impedance booster 27 increases the impedance of the power receiving circuit 21 and suppresses the communication signal in the current loop CL described later from being absorbed by the power receiving circuit 21. The noise filter 28 reduces the noise included in the power supplied from the commercial power supply 100. The rectifier circuit 29 rectifies the AC power with the noise reduced by the noise filter 28 and converts it into DC power, and outputs the DC power. The smoothing circuit 30 reduces the pulsation included in the output of the rectifier circuit 29.

[0024] The DC power output from the smoothing circuit 30 is supplied to the fan inverter 22 and the switching power supply 31. The switching power supply 31 converts the voltage supplied from the smoothing circuit 30 into a DC voltage smaller than the supplied voltage and supplies it to the devices inside the indoor unit 12. The switching power supply 31 supplies power to, for example, the MCU 23, the high-frequency transceiver circuit 24, the low-frequency receiving circuit 25, and the low-frequency transceiver circuit 26.

[0025] The indoor unit 12 and the outdoor unit 11 are connected by a first communication wiring Wt1 constituted by a power line L1 forming part of the power supply wiring Wa2 and a communication line L2. This first communication wiring Wt1 forms a current loop CL between the indoor unit 12 and the outdoor unit 11. The indoor unit 12 can transmit and receive low-frequency current signals via the current loop CL by means of a low-frequency transmission and reception circuit 26.

[0026] The indoor unit 12 includes a band-pass filter 32, an attenuation device 33, a coupling circuit 34, and a noise filter 35. The band-pass filter 32 allows a high-frequency voltage signal (high-frequency signal) transmitted and received by the high-frequency transmission and reception circuit 24 to pass through. The band-pass filter 32 is connected to the wiring of the current loop CL via the attenuation device 33, the coupling circuit 34, and the noise filter 35. Therefore, the high-frequency transmission and reception circuit 24 can transmit and receive high-frequency signals via the wiring of the current loop CL.

[0027] The attenuation device 33 attenuates the high-frequency signal transmitted from the high-frequency transmission and reception circuit 24 and reduces the signal intensity. Specifically, the high-frequency signal transmitted from the high-frequency transmission and reception circuit 24 is transmitted to the outdoor unit 11 through the first communication wiring Wt1 and received by the high-frequency transmission and reception circuit 44 of the outdoor unit 11. If the signal intensity of the high-frequency signal is high, the signal sent from the first communication wiring Wt1 to the outdoor unit 11 may leak to the commercial power supply 100 side along the path indicated by the arrow X1. Such leaked high-frequency signals may violate regulations such as the Radio Law depending on their signal intensity. In this embodiment, in order to suppress such leakage of high-frequency signals, the attenuation device 33 attenuates the high-frequency signal. The attenuation device 33 of this embodiment is configured to be able to change the attenuation amount of the high-frequency signal. The adjustment of the attenuation amount by the attenuation device 33 will be described later.

[0028] The coupling circuit 34 is a circuit that allows the AC component to pass through while blocking the DC component for the transmission and reception of high-frequency signals. The coupling circuit 34 is constituted by, for example, a coupling capacitor. The coupling circuit 34 allows the high-frequency signal transmitted through the wiring of the current loop CL to pass through. The noise filter 35 reduces the noise of the high-frequency signal that has passed through the coupling circuit 34.

[0029] The high-frequency transmission and reception circuit 24 of the indoor unit 12 is connected to the second communication wiring Wt2 via a high-pass filter 36. The high-frequency transmission and reception circuit 24 can transmit and receive high-frequency signals through the second communication wiring Wt2.

[0030] The low-frequency reception circuit 25 of the indoor unit 12 is connected to the second communication wiring Wt2 via a low-pass filter 37. The low-frequency reception circuit 25 of the indoor unit 12 can receive low-frequency signals through the second communication wiring Wt2. The high-frequency signal and the low-frequency signal transmitted and received through the second communication wiring Wt2 are voltage signals that transmit information by changing the voltage.

[0031] In the present disclosure, the high-frequency signal is a signal with a frequency of 100 kHz or more, and the low-frequency signal is a signal with a frequency of 10 kHz or less.

[0032] (Configuration of the outdoor unit) The outdoor unit 11 includes a power reception circuit 41. The power reception circuit 41 receives power from the commercial power supply 100 and supplies power to the devices inside the outdoor unit 11. The outdoor unit 11 includes an inverter 47, a fan inverter 42, an MCU 43, a high-frequency transmission and reception circuit 44, a low-frequency transmission circuit 45, and a low-frequency transmission and reception circuit 46. These are driven by the power supplied to the inside of the outdoor unit 11 by the power reception circuit 41.

[0033] The outdoor unit 11 includes a compressor, an outdoor fan, and an outdoor heat exchanger (not shown). The compressor compresses the refrigerant and circulates the refrigerant between the outdoor unit 11 and the indoor unit 12. The inverter 47 supplies power to the compressor to operate the compressor. The fan inverter 42 is an inverter for operating the outdoor fan. The outdoor fan generates an air flow passing through the outdoor heat exchanger. The MCU 43 functions as a control unit for controlling the internal devices of the outdoor unit 11.

[0034] The MCU 43 includes a processor and a memory. The processor of the MCU 43 is composed of a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), a gate array, or an FPGA (Field Programmable Gate Array), etc. The ASIC, or a programmable logic device such as a gate array or an FPGA, is configured to be able to execute the same processing as the control program.

[0035] The memory of the MCU 23 includes a volatile memory such as an SRAM (Static Random Access Memory) or a DRAM (Dynamic Random Access Memory), and a non-volatile memory such as a flash memory, a hard disk, or a ROM (Read Only Memory). The control program and control data, which are computer programs, are stored in the non-volatile memory. The indoor unit 12 exhibits various functions when the processor executes the control program.

[0036] The power receiving circuit 41 includes a noise filter 48, a rectifier circuit 49, a smoothing circuit 50, and a switching power supply 51. The noise filter 48 reduces the noise contained in the power supplied from the commercial power supply 100. The rectifier circuit 49 rectifies the AC power with the noise reduced by the noise filter 48 and converts it into DC power, and outputs the DC power.

[0037] The smoothing circuit 50 reduces the pulsation contained in the output of the rectifying circuit 49. The DC power output from the smoothing circuit 50 is supplied to the inverter 47 and the fan inverter 42.

[0038] The switching power supply 51 rectifies the AC power with the noise reduced by the noise filter 48, converts it into DC power, and outputs the DC power to the devices inside the outdoor unit 11. The switching power supply 51 supplies power to, for example, the MCU 43, the high-frequency transceiver circuit 44, the low-frequency transmission circuit 45, and the low-frequency transceiver circuit 46.

[0039] A power supply wiring Wa2 for supplying the power from the commercial power supply 100 to the indoor unit 12 is connected to the outdoor unit 11. The outdoor unit 11 includes a low-pass filter 58 for reducing the high-frequency noise superimposed on the power to supply power to the indoor unit 12 via the power supply wiring Wa2. This low-pass filter 58 also reduces the high-frequency components of the signal flowing from the outdoor unit 11 to the commercial power supply 100 side.

[0040] The outdoor unit 11 performs transmission and reception of low-frequency current signals via the current loop CL by the low-frequency transceiver circuit 46. The frequencies of the current signals of the low-frequency transceiver circuit 46 of the outdoor unit 11 and the low-frequency transceiver circuit 26 of the indoor unit 12 are preferably set to be the same as the frequency of the commercial power supply 100 applied to the power supply wiring Wa2.

[0041] The outdoor unit 11 includes a band-pass filter 52, an attenuation device 53, a coupling circuit 54, and a noise filter 55. The band-pass filter 52 passes the high-frequency voltage signal transmitted and received by the high-frequency transceiver circuit 44. The band-pass filter 52 is connected to the current loop CL via the attenuation device 53, the coupling circuit 54, and the noise filter 55. Therefore, the high-frequency transceiver circuit 44 can transmit and receive the high-frequency voltage signal via the wiring of the current loop CL.

[0042] The attenuation device 53 attenuates the high-frequency signal transmitted from the high-frequency transceiver circuit 44 and reduces the signal strength. The high-frequency signal transmitted from the high-frequency transceiver circuit 44 is transmitted to the indoor unit 12 through the first communication wiring Wt1 and received by the high-frequency transceiver circuit 24 of the indoor unit 12. However, if the signal strength of the high-frequency signal is high, there is a possibility of leakage from the current loop CL to the commercial power supply 100 side through the path indicated by the arrow X2 in FIG. 2. To suppress such leakage of the high-frequency signal, the attenuation device 53 attenuates the high-frequency signal. Different from the attenuation device 33 of the indoor unit 12, a device with a fixed attenuation amount of the high-frequency signal is used for this attenuation device 53 of the outdoor unit 11.

[0043] The coupling circuit 54 is a circuit that allows the AC component to pass through without allowing the DC component to pass through for the transmission and reception of high-frequency signals. The coupling circuit 54 is composed of, for example, a coupling capacitor. The coupling circuit 54 allows the high-frequency signal transmitted using the current loop CL to pass through. The noise filter 55 reduces the noise of the high-frequency signal that has passed through the coupling circuit 54.

[0044] The high-frequency transceiver circuit 44 of the outdoor unit 11 is connected to the second communication wiring Wt2 via a high-pass filter 56. The high-frequency transceiver circuit 44 can transmit and receive high-frequency signals through the second communication wiring Wt2.

[0045] The low-frequency transmission circuit 45 of the outdoor unit 11 is connected to the second communication wiring Wt2 via a low-pass filter 57. The low-frequency transmission circuit 45 of the outdoor unit 11 can transmit low-frequency signals through the second communication wiring Wt2.

[0046] The outdoor unit 11 and the indoor unit 12 can communicate using a current loop CL via the first communication wiring Wt1. The low-frequency signal used in the communication using the current loop CL is sent from the low-frequency transceiver circuit 26 of the indoor unit 12 through the first communication wiring Wt1 (power line L1 and communication line L2) to the low-frequency transceiver circuit 46 of the outdoor unit 11. Also, the low-frequency signal is sent from the low-frequency transceiver circuit 46 of the outdoor unit 11 through the first communication wiring Wt1 (power line L1 and communication line L2) to the low-frequency transceiver circuit 26 of the indoor unit 12. This low-frequency signal is a current signal due to the change in the current flowing through the power line L1 and the communication line L2.

[0047] The outdoor unit 11 and the indoor unit 12 can communicate high-frequency signals using the first communication wiring Wt1. The high-frequency signal is transmitted from the high-frequency transceiver circuit 44 of the outdoor unit 11 and is sent to the high-frequency transceiver circuit 24 of the indoor unit 12 via the band-pass filter 52, the attenuation device 53, the coupling circuit 54, the noise filter 55, the first communication wiring Wt1 (power line L1 and communication line L2), the noise filter 35, the coupling circuit 34, the attenuation device 33, and the band-pass filter 32.

[0048] Also, the high-frequency signal is sent from the high-frequency transceiver circuit 24 of the indoor unit 12 to the high-frequency transceiver circuit 44 of the outdoor unit 11 via the band-pass filter 32, the attenuation device 33, the coupling circuit 34, the noise filter 35, the first communication wiring Wt1 (power line L1 and communication line L2), the noise filter 55, the coupling circuit 54, the attenuation device 53, and the band-pass filter 52.

[0049] The outdoor unit 11, the indoor unit 12, and the central controller 13 can communicate using the second communication wiring Wt2. The central controller 13 can include, for example, the same MCU, high-frequency transceiver circuit, and low-frequency receiving circuit as the outdoor unit 11 or the indoor unit 12, and can communicate using high-frequency signals and low-frequency signals. The internal configuration for communication of the central controller 13 can use the same configuration as the outdoor unit 11 or the indoor unit 12.

[0050] The low-frequency signal transmitted from the low-frequency transmission circuit 45 of the outdoor unit 11 is received by the low-frequency reception circuit 25 of the indoor unit 12 via the low-pass filter 57, the second communication wiring Wt2, and the low-pass filter 37. This low-frequency signal is used, for example, to recognize each system when there are multiple refrigerant circuits formed by the outdoor unit 11, the indoor unit 12, and the refrigerant pipe P.

[0051] The high-frequency signal transmitted from the high-frequency transmission / reception circuit 44 of the outdoor unit 11 is transmitted to the high-frequency transmission / reception circuit 24 of the indoor unit 12 via the high-pass filter 56, the second communication wiring Wt2, and the high-pass filter 36. The high-frequency signal transmitted from the high-frequency transmission / reception circuit 24 of the indoor unit 12 is received by the high-frequency transmission / reception circuit 44 of the outdoor unit 11 via the high-pass filter 36, the second communication wiring Wt2, and the high-pass filter 56. This high-frequency signal is used, for example, for the aforementioned system recognition and communication between the outdoor unit 11 and the indoor unit 12 during normal operation of the air conditioner 10 after system recognition.

[0052] Similar to the transmission and reception of the low-frequency signal and the high-frequency signal between the outdoor unit 11 and the indoor unit 12, the low-frequency signal and the high-frequency signal can be transmitted and received between the outdoor unit 11 and the centralized controller 13. Also, the high-frequency signal can be transmitted and received between the centralized controller 13 and the indoor unit 12. Note that the communication between the centralized controller 13 and the indoor unit 12 using the high-frequency signal can be performed using the high-frequency transmission / reception circuit of the centralized controller 13 and the high-frequency transmission / reception circuit 24 of the indoor unit 12. Similar to the transmission and reception of the low-frequency signal and the high-frequency signal between the outdoor unit 11 and the indoor unit 12, it may be configured such that the low-frequency signal and the high-frequency signal can be transmitted and received between the centralized controller 13 and the outdoor unit 11 and the indoor unit 12.

[0053] (Control of the attenuation device 33) FIG. 3 is a schematic configuration diagram of the attenuation device. As described above, the attenuation device 33 provided in the indoor unit 12 is configured to be able to change the attenuation amount of the high-frequency signal. The attenuation device 33 includes a plurality of attenuators 61a, 61b, 61c, 61d and a plurality of switches 62a, 62b, 62c, 62d, 62z between the input terminal 60a and the output terminal 60b. The plurality of attenuators 61a, 61b, 61c, 61d each include a resistance element that attenuates the high-frequency signal. The plurality of attenuators 61a, 61b, 61c, 61d are connected in parallel with each other. The plurality of attenuators 61a, 61b, 61c, 61d attenuate the high-frequency signal with different attenuation amounts. For example, the attenuator 61a attenuates the high-frequency signal with an attenuation amount of 5 dB, the attenuator 61b attenuates the high-frequency signal with an attenuation amount of 10 dB, the attenuator 61c attenuates the high-frequency signal with an attenuation amount of 15 dB, and the attenuator 61d attenuates the high-frequency signal with an attenuation amount of 20 dB.

[0054] The plurality of switches 62a, 62b, 62c, 62d are provided in series corresponding to the plurality of attenuators 61a, 61b, 61c, 61d. The plurality of switches 62a, 62b, 62c, 62d switch the presence or absence of the input of the high-frequency signal to each attenuator 61a, 61b, 61c, 61d. Another switch 62z does not correspond to any of the attenuators and forms a path of the high-frequency signal that does not pass through any of the attenuators. The plurality of switches 62a, 62b, 62c, 62d, 62z are turned on and off by the MCU 23.

[0055] The attenuation device 33 of the present embodiment can adjust the attenuation amount by selectively turning on any one of the plurality of switches 62a, 62b, 62c, 62d, 62z. Since the attenuation device 33 of the present embodiment includes four attenuators 61a, 61b, 61c, 61d and five switches 62a, 62b, 62c, 62d, the attenuation amount can be adjusted in five steps including 0. Further, the attenuation device 33 of the present embodiment can also adjust the attenuation amount in more steps by selectively turning on two or more of the plurality of switches 62a, 62b, 62c, 62d.

[0056] The MCU 23 of the indoor unit 12 controls the attenuation device 33. Specifically, the MCU 23 controls (adjusts) the attenuation amount of the high-frequency signal by the attenuation device 33. The MCU 23 adjusts the attenuation amount of the high-frequency signal by the attenuation device 33 by selectively turning on a plurality of switches 62a, 62b, 62c, 62d of the attenuation device 33. In the present embodiment, based on the length of the first communication wiring Wt1 between the outdoor unit 11 and the indoor unit 12, in other words, the distance between the outdoor unit 11 and the indoor unit 12, the MCU 23 adjusts the attenuation amount by the attenuation device 33.

[0057] The high-frequency signal, which is a voltage signal transmitted between the outdoor unit 11 and the indoor unit 12, is attenuated by the resistance of the first communication wiring Wt1 as it passes through the first communication wiring Wt1. The attenuation amount of the high-frequency signal in the first communication wiring Wt1 changes according to the length of the first communication wiring Wt1. For example, when the first communication wiring Wt1 becomes shorter, the attenuation amount of the high-frequency signal becomes smaller, and when the first communication wiring Wt1 becomes longer, the attenuation amount of the high-frequency signal becomes larger. Therefore, the longer the first communication wiring Wt1, the greater the impact of the attenuation amount by the first communication wiring Wt1 on the communication of the high-frequency signal.

[0058] In order to suppress the leakage of the high-frequency signal to the commercial power supply 100 side shown by the path X1 in FIG. 2, it is necessary to attenuate the high-frequency signal with a predetermined attenuation amount regardless of the length of the first communication wiring Wt1. Therefore, assuming that the attenuation amount of the high-frequency signal by the attenuation device 33 is fixed at a constant value, even if the high-frequency signal can be attenuated with an appropriate attenuation amount in the first communication wiring Wt1 of a certain length, in the first communication wiring Wt1 longer than that length, the high-frequency signal may be excessively attenuated, which may cause a problem in communication. As a result, the length of the first communication wiring Wt1 is limited to a predetermined value, and there are also restrictions on the installation of the air conditioner 10, particularly the installation interval between the outdoor unit 11 and the indoor unit 12. Further, assuming that the attenuation amount of the high-frequency signal by the attenuation device 33 is fixed at a constant value, even if the high-frequency signal can be attenuated with an appropriate attenuation amount in the first communication wiring Wt1 of a certain length, in the first communication wiring Wt1 shorter than that length, the high-frequency signal may not be sufficiently attenuated, and there is a possibility that the leakage of the high-frequency signal to the commercial power supply 100 side cannot be appropriately suppressed.

[0059] In view of the above circumstances, in this embodiment, a damping device 33 capable of changing the damping amount is applied, and further, the MCU 23 controls the damping device 33 based on the damping amount of the high-frequency signal through the first communication wiring Wt1, and adjusts the damping amount of the high-frequency signal by the damping device 33. Hereinafter, the control procedure of the damping device by the MCU 23 will be described.

[0060] FIG. 4 is a table illustrating the relationship between the PHY rate and the damping amount. FIG. 5 is a flowchart showing the procedure for controlling the damping amount by the damping device. The MCU 23 of this embodiment stores information such as the table shown in FIG. 4 or an arithmetic expression corresponding to the table in the memory. The PHY rate shown in FIG. 4 is information indicating the communication quality between the high-frequency transmission / reception circuit 24 of the indoor unit 12 and the high-frequency transmission / reception circuit 44 of the outdoor unit 11. The PHY rate is substantially the communication speed (Mbps) when a predetermined signal is transmitted between the two high-frequency transmission / reception circuits 24 and 44. The high-frequency transmission / reception circuits 24 and 44 have a function of measuring the PHY rate.

[0061] The damping amount shown in FIG. 4 is an estimated value of the damping amount of the high-frequency signal by the first communication wiring Wt1 corresponding to the PHY rate. In FIG. 4, an estimated value of the wiring length, which is the length of the first communication wiring Wt1, is also shown for reference. These estimated values can be values obtained from test results actually performed using the first communication wiring Wt1, the characteristics of the first communication wiring Wt1, and the like. Note that the relationship between the PHY rate, the damping amount, and the wiring length of the first communication wiring Wt1 in FIG. 4 is merely an example. The PHY rate is affected by the configuration related to the communication between the outdoor unit 11 and the indoor unit 12 of the air conditioner 10 shown in FIG. 2, and the type and winding method of the first communication wiring Wt1. Therefore, the relationship between the PHY rate, the damping amount, and the wiring length of the first communication wiring Wt1 is obtained in advance for each air conditioner 10.

[0062] In step S1 of FIG. 5, the MCU 23 acquires the value of PHYrate from the high-frequency transceiver circuit 24. Next, in step S2, the MCU 23 obtains the attenuation amount of the high-frequency signal in the first communication wiring Wt1 using the acquired PHYrate. For example, when the input PHYrate is 200 Mbps, the MCU 23 obtains the attenuation amount (5 dB) by the first communication wiring Wt1 based on the relationship shown in FIG. 4.

[0063] Next, in step S3, the MCU 23 determines the attenuation amount of the high-frequency signal by the attenuation device 33. Specifically, the MCU 23 needs to attenuate the high-frequency signal transmitted from the high-frequency transceiver circuit 24 of the indoor unit 12 over the entire path (leakage path) X1 from the high-frequency transceiver circuit 24 to the commercial power supply 100 in order to prevent the high-frequency signal from leaking to the commercial power supply 100 side. The MCU 23 obtains the attenuation amount of the high-frequency signal by the attenuation device 33 from the relationship between the attenuation amount of the high-frequency signal required for the entire leakage path X1 and the attenuation amount of the high-frequency signal by the first communication wiring Wt1. For example, when the attenuation amount required for the entire leakage path X1 is "20 dB" and the attenuation amount by the first communication wiring Wt1 is "5 dB", a value obtained by subtracting the latter from the former (20 dB - 5 dB = 15 dB) is obtained and determined as the attenuation amount by the attenuation device 33.

[0064] Finally, in step S4, the MCU 23 controls the attenuation device 33 so that the attenuation amount by the attenuation device 33 becomes the attenuation amount determined in step S3. Specifically, the attenuation amount of the attenuation device 33 is adjusted by selectively turning on the plurality of switches 62a to 62d, 62z shown in FIG. 3.

[0065] Note that the attenuation device 53 of the outdoor unit 11 is not affected by the attenuation by the first communication wiring Wt1 when suppressing the leakage of the high-frequency signal transmitted from the high-frequency transceiver circuit 44 of the outdoor unit 11 to the commercial power supply 100 side. Therefore, the attenuation device 53 of the outdoor unit 11 attenuates the high-frequency signal with a fixed attenuation amount that cannot be changed.

[0066] [Second Embodiment] FIG. 6 is a schematic configuration diagram of an attenuation device of an air conditioner according to the second embodiment. The attenuation device 33 shown in Fig. 6 includes a known attenuator 63 (so-called programmable attenuator) whose attenuation amount can be adjusted by software. This attenuation device 33 can obtain an arbitrary attenuation amount stepwise with a predetermined resolution according to a control signal transmitted from the MCU 23. In this embodiment, it is not necessary to provide a plurality of attenuators and a plurality of switches like the attenuation device 33 of the first embodiment, and the attenuation device 33 can be simply configured.

[0067] [Third Embodiment] Fig. 7 is a block diagram showing a configuration related to communication between the outdoor unit and the indoor unit of the air conditioner according to the third embodiment. In this embodiment, the attenuation device 33 is the wiring of the current loop CL in the indoor unit 12, and the attenuation device 33 is arranged in the leakage path (path indicated by arrow X1) of the high-frequency signal from the noise filter 35 to the commercial power supply 100. Therefore, also in this embodiment, the high-frequency signal can be attenuated by the attenuation device 33, and the leakage to the commercial power supply 100 side can be suppressed.

[0068] In the indoor unit 12, a high-frequency signal with a higher voltage flows through the wiring on the noise filter 35 side than the wiring on the band-pass filter 32 side from the coupling circuit 34. Therefore, a high-frequency signal with a lower voltage than the attenuation device 33 of the third embodiment flows through the attenuation device 33 of the first embodiment, and for the attenuation of the high-frequency signal, one with a smaller resistance value can be used. Therefore, from this viewpoint, it is more preferable to provide the attenuation device 33 between the coupling circuit 34 and the band-pass filter 32 as in the first embodiment.

[0069] [Fourth Embodiment] Fig. 8 is a block diagram showing a configuration related to communication between the outdoor unit and the indoor unit of the air conditioner according to the fourth embodiment. In this embodiment, the attenuation device 33 is provided in the leakage path of the high-frequency signal (the path indicated by the arrow X1) in the outdoor unit 11. Specifically, the attenuation device 33 is provided in the wiring in the outdoor unit 11 that connects the power supply wiring Wa1 and the power supply wiring Wa2. More specifically, the attenuation device 33 of the present embodiment is provided in place of the low-pass filter 58 in the first embodiment (see FIG. 2). However, the attenuation device 33 may be provided together with the low-pass filter 58.

[0070] When the attenuation device 33 is provided in the outdoor unit 11, the MCU 43 of the outdoor unit 11 controls the attenuation device 33. Information such as the table shown in FIG. 4 or an arithmetic formula corresponding to the table is stored in the memory of the MCU 43. The high-frequency transmission / reception circuit 44 of the outdoor unit 11 has a function of measuring PHYrate as information indicating the communication quality between the high-frequency transmission / reception circuit 24 of the indoor unit 12. The MCU 43 acquires the PHYrare from the high-frequency transmission / reception circuit 44, obtains the attenuation amount in the communication wiring Wt1 based on the table shown in FIG. 4, and can adjust the attenuation amount in the attenuation device 33.

[0071] [Other Embodiments] The installation location of the attenuation device 33 is not particularly limited as long as it is in the leakage path X1 of the high-frequency signal. The attenuation device 33 can also be installed by combining both the type shown in FIG. 3 and the type shown in FIG. 6. The attenuation device 53 provided in the outdoor unit 11 is not limited to the one in which the attenuation amount of the high-frequency signal is fixed, and may be configured to be able to change the attenuation amount.

[0072] For the attenuation device 33 illustrated in FIG. 3, the attenuation amounts of the plurality of attenuators 61a, 61b, 61c, and 61d may be the same. In this case, the attenuation amount can be adjusted by changing the number of switches that are turned on among the plurality of switches 62a, 62b, 62c, and 62d.

[0073] [Functions and Effects of the Embodiment] (1) The air conditioner 10 of the above embodiment includes an indoor unit 12, an outdoor unit 11, a transmission circuit (high-frequency transmission and reception circuit) 24 provided in the indoor unit 12 for transmitting a high-frequency signal, a reception circuit (high-frequency transmission and reception circuit) 44 provided in the outdoor unit 11 for receiving the high-frequency signal from the indoor unit 12, a power supply wiring (second power supply wiring) Wa2 connecting the outdoor unit 11 and the indoor unit 12 and supplying power from the outdoor unit 11 to the indoor unit 12, a communication wiring (first communication wiring) Wt1 connecting the outdoor unit 11 and the indoor unit 12 and including a power line L1 constituting a part of the power supply wiring Wa2 for transmitting the high-frequency signal from the transmission circuit 24 to the reception circuit 44, an attenuation device 33 for attenuating the high-frequency signal transmitted from the transmission circuit 24, and a control unit (MCU) 23, 43 for controlling the attenuation amount of the high-frequency signal by the attenuation device 33. Thereby, the signal strength of the high-frequency signal from the transmission circuit 24 to the reception circuit 44 can be reduced, and the leakage of the high-frequency signal from the outdoor unit 11 to the commercial power supply 100 can be suppressed.

[0074] (2) In the above embodiment, the control units 23, 43 control the attenuation amount by the attenuation device 33 based on the attenuation amount of the high-frequency signal in the communication wiring Wt1. The communication wiring Wt1 attenuates the high-frequency signal by itself acting as a resistor. The attenuation amount of the high-frequency signal in this communication wiring Wt1 changes according to the length of the communication wiring Wt1, in other words, the communication distance between the indoor unit 12 and the outdoor unit 11. For example, when the communication wiring Wt1 becomes longer, the attenuation amount of the high-frequency signal becomes larger, and when the communication wiring becomes shorter, the attenuation amount of the high-frequency signal becomes smaller. According to the above configuration, the control units 23, 43 control the attenuation amount by the attenuation device 33 based on the attenuation amount of the high-frequency signal in the communication wiring Wt1. Therefore, when the communication wiring Wt1 is short, by increasing the attenuation amount by the attenuation device 33, it is possible to ensure the overall attenuation amount (the entire leakage path X1) required for suppressing the leakage of the high-frequency signal. Conversely, when the communication wiring Wt1 is long, even if the attenuation amount by the attenuation device 33 is reduced, the required overall attenuation amount can be ensured. In other words, by reducing the attenuation amount by the attenuation device 33, the communication distance can be extended.

[0075] (3) In the above embodiment, the control units 23 and 43 obtain the attenuation amount of the high-frequency signal in the communication wiring Wt1, and determine the attenuation amount of the high-frequency signal by the attenuation device 33 based on this attenuation amount. Thereby, the control of the attenuation amount by the control units 23 and 43 can be realized.

[0076] (4) In the above embodiment, the control units 23 and 43 obtain information regarding the communication quality of the communication wiring Wt1, and obtain the attenuation amount of the high-frequency signal in the communication wiring Wt1 based on this information. The communication quality of the communication wiring Wt1 varies depending on the length of the communication wiring Wt1, similarly to the attenuation amount. Therefore, there is a correlation between the communication quality of the communication wiring Wt1 and the attenuation amount, and the attenuation amount can be obtained using the information regarding the communication quality.

[0077] (5) In the above embodiment, the attenuation device 33 includes an attenuator 63 whose attenuation amount can be adjusted under the control of the control units 23 and 43. Thereby, the attenuation amount of the high-frequency signal can be controlled using an attenuation device 33 having a simple structure.

[0078] (6) In the above embodiment, the attenuation device 33 includes a plurality of attenuators 61a to 61d having a predetermined attenuation amount, and the control units 23 and 43 control the attenuation amount by the attenuation device 33 by changing the number or type of the attenuators 61a to 61d connected to the communication wiring Wt1. Thereby, the attenuation amount can be easily controlled.

[0079] (7) In the above embodiment, a second communication wiring Wt2 is provided for transmitting a high-frequency signal from the transmission circuit 24 to another device (for example, a central controller) 13 through a path different from the communication wiring Wt1. Thereby, the attenuation amount by the attenuation device 33 can be controlled without affecting the communication between the transmission circuit 24 and another device 13. Here, the "another device" is not limited to the central controller 13, and can be another indoor unit 12 or other communicable devices.

[0080] As described above, the embodiments have been explained, but it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims.

Explanation of Symbols

[0081] 10: Air conditioner 11: Outdoor unit 12: Indoor unit 13: Central controller 23: MCU (Control unit) 24: High-frequency transceiver circuit (Transmission circuit) 33: Attenuation device 43: MCU (Control unit) 44: High-frequency transceiver circuit (Receiving circuit) 61a: Attenuator 61b: Attenuator 61c: Attenuator 61d: Attenuator 63: Attenuator L1: Power line L2: Communication line Wa2: Power supply wiring Wt1: First communication wiring Wt2: Second communication wiring

Claims

1. An indoor unit (12), an outdoor unit (11) supplied with power from a commercial power supply (100), a transmission circuit (24) provided in the indoor unit (12) for transmitting a high-frequency signal, a reception circuit (44) provided in the outdoor unit (11) for receiving the high-frequency signal from the indoor unit (12), a power supply wiring (Wa2) connecting the outdoor unit (11) and the indoor unit (12) and supplying power from the outdoor unit (11) to the indoor unit (12), a communication wiring (Wt1) connecting the outdoor unit (11) and the indoor unit (12), including a power line (L1) that forms part of the power supply wiring (Wa2), and transmitting a high-frequency signal from the transmission circuit (24) to the reception circuit (44), an attenuation device (33) for attenuating the high-frequency signal transmitted from the transmission circuit (24), a control unit (23, 43) for controlling the attenuation amount of the high-frequency signal by the attenuation device (33), an air conditioner, wherein the attenuation device (33) is arranged on a path of the high-frequency signal including the communication wiring (Wt1) from the transmission circuit (24) to the commercial power supply (100).

2. The air conditioner according to claim 1, wherein the control unit (23, 43) controls the attenuation amount by the attenuation device (33) based on the attenuation amount of the high-frequency signal in the communication wiring (Wt1).

3. The air conditioner according to claim 2, wherein the control unit (23, 43) obtains the attenuation amount of the high-frequency signal in the communication wiring (Wt1) and determines the attenuation amount of the high-frequency signal by the attenuation device (33) based on this attenuation amount.

4. The air conditioner according to claim 3, wherein the control unit (23, 43) acquires information regarding the communication quality of the communication wiring (Wt1) and obtains the attenuation amount of the high-frequency signal in the communication wiring (Wt1) based on the information.

5. The air conditioner according to any one of claims 1 to 4, wherein the attenuation device (33) includes an attenuator (63) whose attenuation amount can be adjusted under the control of the control unit (23, 43).

6. The attenuation device (33) includes a plurality of attenuators (61a, 61b, 61c, 62d) having a predetermined attenuation amount, The air conditioner according to any one of claims 1 to 4, wherein the control unit (23, 43) controls the attenuation amount by the attenuation device by changing the number or type of the attenuators connected to the communication wiring (Wt1).

7. The air conditioner according to any one of claims 1 to 4, further comprising a second communication wiring (Wt2) that transmits a high-frequency signal from the transmission circuit (24) to another device (13) through a path different from the communication wiring (Wt1).

8. An indoor unit (12), an outdoor unit (11), a transmission circuit (24) provided in the indoor unit (12) for transmitting a high-frequency signal, a reception circuit (44) provided in the outdoor unit (11) for receiving the high-frequency signal from the indoor unit (12), a power supply wiring (Wa2) that connects the outdoor unit (11) and the indoor unit (12) and supplies power from the outdoor unit (11) to the indoor unit (12), a communication wiring (Wt1) that connects the outdoor unit (11) and the indoor unit (12), includes a power line (L1) that forms part of the power supply wiring (Wa2), and transmits a high-frequency signal from the transmission circuit (24) to the reception circuit (44), an attenuation device (33) that attenuates the high-frequency signal transmitted from the transmission circuit (24), and a control unit (23, 43) that controls the attenuation amount of the high-frequency signal by the attenuation device (33), wherein the control unit (23, 43) controls the attenuation amount by the attenuation device (33) based on the attenuation amount of the high-frequency signal in the communication wiring (Wt1).

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