JP7607448B2 - Air conditioning system and transmission path estimation method - Google Patents

Description

This disclosure relates to an air conditioning system and a transmission path estimation method.

The center frequency and frequency band of noise generated by inverter circuits vary depending on the model, installation environment, and the rotation speed of the drive components (compressor, fan, etc.). Conventionally, in air conditioning systems that communicate using multi-carrier signals, it has been known to suppress the occurrence of communication anomalies by not using subcarriers in the frequency fluctuation range of noise that has been found through knowledge (for example, Patent Document 1).

In this case, subcarriers in frequency bands where noise is not actually generated or where the impact of noise is small will not be used, resulting in an excessive reduction in communication speed. In addition, there is the problem that it is not possible to deal with noise generated at frequencies other than the frequency bands previously assumed.

In response to this, a method is known in which transmission path estimation (also called channel estimation) is performed periodically to determine an optimal tone map (a summary of information about each subcarrier, such as whether it is in use or not, the number of bits to be allocated (i.e., modulation method), etc.) that matches the noise environment of the transmission path (for example, Patent Document 2).

Patent No. 6702471 International Publication No. 2012/014502

However, the above-mentioned transmission path estimation method requires regular communication using a communication frame dedicated to the estimation, which may affect the actual data communication traffic and lead to a decrease in communication speed.

The present disclosure has been made to solve the above problems, and aims to provide an air conditioning system and a transmission path estimation method that can reduce the effects of noise by using an optimal tone map while suppressing a decrease in communication speed.

In order to achieve the above object, the air conditioning system according to the present disclosure comprises:
An air conditioning system comprising an outdoor unit and an indoor unit, the outdoor unit and the indoor unit communicating with each other via a multicarrier signal,
a transmission path estimation necessity determination means for determining whether or not it is necessary to perform transmission path estimation;
a transmission channel estimation means for executing a transmission channel estimation to evaluate a signal quality of each subcarrier of the multicarrier signal when it is determined by the transmission channel estimation necessity determination means that it is necessary to execute the transmission channel estimation, and for determining a tone map;
The transmission path estimation necessity determining means determines that it is necessary to perform transmission path estimation when an inverter control state of the outdoor unit or the indoor unit changes .

According to the present disclosure, it is possible to suppress a decrease in communication speed while reducing the effects of noise through an optimal tone map.

FIG. 1 is a diagram showing an overall configuration of an air conditioning system according to a first embodiment. FIG. 1 is a block diagram showing a hardware configuration of an outdoor unit according to a first embodiment. FIG. 1 is a block diagram showing a hardware configuration of an indoor unit according to a first embodiment. FIG. 1 is a block diagram showing the functional configuration of a control circuit and a communication circuit provided in an outdoor unit and an indoor unit in a first embodiment. FIG. 1 shows an example of a multicarrier signal before a tone map is changed in the first embodiment. FIG. 1 shows an example of a multicarrier signal after a tone map is changed in the first embodiment. A flowchart showing the procedure of a transmission channel estimation process executed by the air conditioning system in the first embodiment. FIG. 11 is a block diagram showing the functional configuration of a control circuit provided in each of an outdoor unit and an indoor unit according to a second embodiment. FIG. 13 is a diagram showing the overall configuration of an air conditioning system according to a third embodiment. FIG. 13 is a block diagram showing the functional configuration of a control circuit provided in each of an outdoor unit and an indoor unit according to a third embodiment. FIG. 13 is a diagram showing the overall configuration of an air conditioning system according to a fourth embodiment. FIG. 13 is a block diagram showing the functional configuration of a control circuit provided in each of an outdoor unit and an indoor unit according to a fourth embodiment.

The following describes in detail the embodiments of the present disclosure with reference to the drawings.

(Embodiment 1)
1 is a diagram showing the overall configuration of an air conditioning system 1 in embodiment 1. The air conditioning system 1 is a system that is installed in a building such as a building or a store, for example, and performs air conditioning within the building, and includes an outdoor unit 2 and one or more indoor units 3. The air conditioning system 1 is an example of an air conditioning system according to the present disclosure.

The outdoor unit 2 and each indoor unit 3 are connected to a communication line 4 for communication by multicarrier signals. The outdoor unit 2 and each indoor unit 3 are also connected via refrigerant piping (not shown) for circulating refrigerant. If communication by multicarrier signals is possible, communication between the outdoor unit 2 and each indoor unit 3 may be performed wirelessly.

The outdoor unit 2 is an example of an outdoor unit according to the present disclosure. As shown in FIG. 2, the outdoor unit 2 includes a driving component 20, an inverter circuit 21, a control circuit 22, and a communication circuit 23. The driving component 20 is, for example, a compressor that compresses a refrigerant, a fan that draws in outside air and sends the air after heat exchange outdoors, etc. The inverter circuit 21 is a circuit that drives the driving component 20.

The control circuit 22 is a circuit that controls the inverter circuit 21 and the communication circuit 23. Although not shown, the control circuit 22 includes a CPU (Central Processing Unit) that controls the control circuit 22 overall, a ROM (Read Only Memory) that stores firmware, a RAM (Random Access Memory) that is used as a working area for the CPU, and an auxiliary storage device that stores programs for controlling the inverter circuit 21 and the communication circuit 23 and data used when the programs are executed. The auxiliary storage device is composed of a readable and writable non-volatile semiconductor memory such as an EEPROM (Electrically Erasable Programmable Read-Only Memory) or a flash memory.

The communication circuit 23 is a circuit for communicating data with other devices (here, each indoor unit 3) via the communication line 4 in accordance with instructions from the control circuit 22, and although none are shown, it includes a CPU that provides overall control of the communication circuit 23, a ROM that stores firmware for communication, and a RAM that is used as a working area for the CPU.

The indoor unit 3 is an example of an indoor unit according to the present disclosure. As shown in FIG. 3, the indoor unit 3 includes a drive component 30, an inverter circuit 31, a control circuit 32, and a communication circuit 33. The drive component 30 is, for example, a fan that draws in indoor air and sends the air after heat exchange into the room. The inverter circuit 31 is a circuit that drives the drive component 30.

The control circuit 32 is a circuit that controls the inverter circuit 31 and the communication circuit 33. Although not shown, the control circuit 32 includes a CPU that performs overall control of the control circuit 32, a ROM that stores firmware, a RAM that is used as a working area for the CPU, and an auxiliary storage device that stores programs for controlling the inverter circuit 31 and the communication circuit 33 and data used when the programs are executed. The auxiliary storage device is composed of a readable and writable non-volatile semiconductor memory such as an EEPROM or a flash memory.

The communication circuit 33 is a circuit for communicating data with other devices (here, the outdoor unit 2) via the communication line 4 in accordance with instructions from the control circuit 32, and although none are shown, it includes a CPU that provides overall control of the communication circuit 33, a ROM that stores firmware for communication, and a RAM that is used as a working area for the CPU.

Next, the functions of the control circuit 22 and communication circuit 23 provided in the outdoor unit 2, and the control circuit 32 and communication circuit 33 provided in the indoor unit 3 will be described in detail. As shown in FIG. 4, both the control circuit 22 and the control circuit 32 include a normal control unit 40 and a transmission path estimation necessity determination unit 41. In addition, both the communication circuit 23 and the communication circuit 33 include a communication control unit 50, a transmission unit 51, and a reception unit 52.

The normal control unit 40 is a functional unit for controlling the general operation of the inverter circuit 21 (or inverter circuit 31) and the communication circuit 23 (or communication circuit 33). The transmission path estimation necessity determination unit 41 is an example of a transmission path estimation necessity determination means according to the present disclosure. The transmission path estimation necessity determination unit 41 determines whether or not a trigger condition, which will be described later, is satisfied, thereby determining whether or not it is necessary to perform transmission path estimation (also called channel estimation). When the transmission path estimation necessity determination unit 41 determines that it is necessary to perform transmission path estimation, it instructs the communication circuit 23 (or communication circuit 33) to perform transmission path estimation.

The communication control unit 50 controls the execution of transmission path estimation, and encodes/decodes communication data using error correction codes. The transmission unit 51 modulates input data from the communication control unit 50 based on a tone map, generates a communication frame, and transmits it. The reception unit 52 extracts data from the received communication frame, demodulates it based on the tone map, and outputs it to the communication control unit 50.

In detail, the transmission unit 51 includes a modulation unit 510, a tone map control unit 511, a frame generation unit 512, and an inverse wavelet transformation unit 513. The transmission unit 51 modulates (e.g., PAM (Pulse Amplitude Modulation) modulation) the transmission data input from the communication control unit 50. The tone map control unit 511 controls the modulation unit by notifying the modulation method (i.e., multi-value degree) for each subcarrier based on a tone map determined by transmission path estimation described later.

The frame generation unit 512 converts the serial data modulated by the modulation unit 510 into parallel data on the frequency axis, and generates a communication frame using a preamble and a pilot symbol (a signal for compensating for amplitude and phase fluctuations on the receiving side), which are known signals. The inverse wavelet transformation unit 513 converts the communication frame generated by the frame generation unit 512 into data on the time axis by inverse wavelet transformation, and transmits it via an analog unit (AFE (Analog Front End)/IC (Integrated Circuit), D/A (Digital to Analog) converter, etc.) not shown.

The receiving unit 52 includes a wavelet transform unit 520, a data extraction unit 521, a transmission path estimation unit 522, and a demodulation unit 523. The wavelet transform unit 520 converts the communication frame received via an analog unit (AFE/IC, A/D (Analog to Digital) converter, etc.) (not shown) into parallel data on the frequency axis by discrete wavelet transform. The data extraction unit 521 converts the parallel data on the frequency axis converted by the wavelet transform unit 520 into serial data and extracts the received data (i.e., payload) from the communication frame. The transmission path estimation unit 522 is an example of a transmission path estimation means according to the present disclosure, and performs transmission path estimation (described later) using the received data extracted by the data extraction unit 521 to determine a tone map. The demodulation unit 523 demodulates the received data extracted by the data extraction unit 521 based on the tone map and outputs it to the communication control unit 50.

Next, we will explain in detail the transmission channel estimation that is realized by cooperation between the outdoor unit 2 and the indoor unit 3. First, when a trigger condition described later is met, the transmitting device (one of the outdoor unit 2 and the indoor unit 3) transmits an RCE (Request Channel Estimation) frame, which is a communication frame for requesting a transmission channel estimation, to the receiving device (the other of the outdoor unit 2 and the indoor unit 3).

The RCE frame clearly indicates that it is an RCE frame in the frame control header, and includes in the payload a known CE (Channel Estimation) signal that is recognized in advance by both the sending and receiving devices.

When the receiving device receives an RCE frame, the quality of the CE signal is evaluated by the transmission channel estimation unit 522, and the CINR (Carrier to Interference and Noise Ratio) for each subcarrier is calculated. In detail, the power error between a known CE signal (+1 or -1) and the actual received signal is calculated, and the root mean square value of this power error is calculated as the average noise amount. The transmission channel estimation unit 522 evaluates the CINR for each subcarrier by comparing the calculated CINR for each subcarrier with predetermined thresholds (first threshold and second threshold, described later).

The transmission channel estimation unit 522 determines a tone map based on the evaluation result of the CINR for each subcarrier. Here, the tone map is a compilation of information about each subcarrier, such as whether it is used (unused subcarriers are masked), the number of bits to be allocated (i.e., the modulation method), and the error correction method. The receiving device stores the tone map determined as described above in memory, and transmits a CER (Channel Estimation Response) frame containing the tone map to the transmitting device.

When the transmitting device receives a CER frame, it extracts the tone map and stores it in memory in association with the device ID of the receiving device that is the sender of the CER frame. The device ID is an ID (identification) for identifying each device (outdoor unit 2, indoor unit 3, etc.) that makes up the air conditioning system 1. This allows the tone map to be shared between the transmitting device and the receiving device. If there are multiple receiving devices, the transmitting device obtains a tone map for each receiving device. For example, if there are three receiving devices (receiving devices A to C), the transmitting device transmits an RCE frame to each of receiving devices A to C, requests a transmission path estimation, and obtains a tone map from each of receiving devices A to C.

The change in tone map due to the above-mentioned transmission path estimation will be specifically described with reference to Figures 5 and 6. Figure 5 shows a state in which a noise component Nx due to the inverter circuit 21 or inverter circuit 31 is mixed into the multicarrier signal Sx before the tone map is changed. In the multicarrier signal Sx, the subcarrier Cm that overlaps with the frequency of the noise component Nx has a poor CINR.

Figure 6 shows the multicarrier signal S1 after the tone map has been changed. As a result of the transmission channel estimation unit 522 determining that the CINR of subcarrier Cm is smaller than the first threshold, subcarrier Cm is masked and is not used for communication. In addition, even if the CINR is equal to or greater than the first threshold, the CINR of a subcarrier that is smaller than a second threshold (a threshold greater than the first threshold) is also considered to have deteriorated. Specifically, although not shown in Figure 6, for example, if the CINR of each of subcarriers Cm-1 and Cm+1 adjacent to subcarrier Cm on the frequency axis is equal to or greater than the first threshold and less than the second threshold, the CINR is considered to have deteriorated due to the influence of noise component Nx, and the modulation method (multi-value) is changed to one in which the number of bits contained in each subcarrier is smaller than before the tone map was changed.

Figure 7 is a flowchart showing the procedure of the transmission path estimation process executed by the air conditioning system 1. In the following transmission path estimation process, the outdoor unit 2 judges whether or not transmission path estimation is required, and transmits the above-mentioned RCE frame to the indoor unit 3. It is an arbitrary design matter which of the outdoor unit 2 and the indoor unit 3 is set as the side that transmits the RCE frame (i.e., the transmitting device). For example, a construction worker, a system administrator, etc. may operate a remote control device (not shown) in the air conditioning system 1 to set the device as the transmitting device, or may switch a switch provided on each of the outdoor unit 2 and the indoor unit 3 to set the device as the transmitting device, or may edit the initial data stored in each of the outdoor unit 2 and the indoor unit 3 to set the device as the transmitting device.

When the indoor unit 3 transmits an RCE frame to the outdoor unit 2, simply substitute the outdoor unit 2 for the indoor unit 3 in the operations of each process in the following flowchart.

(Step S101)
In the outdoor unit 2, the control circuit 22 judges whether or not a trigger condition, which is a requirement for executing the transmission channel estimation and will be described later, is satisfied. If the trigger condition is not satisfied (judgment result: NO), the control circuit 22 continues to judge whether or not the trigger condition is satisfied. On the other hand, if the trigger condition is satisfied (judgment result: YES), the processing of the air conditioning system 1 proceeds to step S102.

(Step S102)
In the outdoor unit 2, the control circuit 22 instructs the communication circuit 23 to execute transmission path estimation. Upon receiving such instruction, the communication circuit 23 transmits an RCE frame, which is a communication frame for requesting transmission path estimation, to all the indoor units 3. Here, the communication circuit 23 of the outdoor unit 2 may transmit the RCE frame to all the indoor units 3 by broadcast or sequentially by unicast.

(Step S103)
In each indoor unit 3, the communication circuit 33 receives the RCE frame and extracts the CE signal from the received RCE frame.

(Step S104)
Following the process of step S103, the communication circuit 33 calculates the CINR for each subcarrier based on the extracted CE signal.

(Step S105)
Following the process of step S104, the communication circuit 33 determines a tone map based on the calculated CINR for each subcarrier.

(Step S106)
Following the process of step S105, the communication circuit 33 stores the determined tone map in memory (a RAM (not shown) provided in the communication circuit 33).

(Step S107)
Furthermore, the communication circuit 33 transmits to the outdoor unit 2 a CER frame in which the determined tone map is stored.

(Step S108)
In the outdoor unit 2, the communication circuit 23 receives the CER frame, and stores the tone map extracted from the received CER frame in memory (a RAM, not shown, provided in the communication circuit 23) in association with the device ID of the indoor unit 3 that sent the frame. Thereafter, the new tone map is used in communications between the outdoor unit 2 and the indoor unit 3.

(Step S109)
Following the processing of step S108, the communication circuit 23 judges whether or not CER frames have been received from all of the indoor units 3. If CER frames have been received from all of the indoor units 3 (determination result: YES), the communication circuit 23 notifies the control circuit 22 of the completion of transmission path estimation, and thereafter, the processing of the air conditioning system 1 returns to step S101. On the other hand, if a CER frame has not been received from any of the indoor units 3 (determination result: NO), the processing of the air conditioning system 1 proceeds to step S110.

(Step S110)
In the outdoor unit 2, the communication circuit 23 sequentially transmits the RCE frame by unicast to all indoor units 3 that have not received the CER frame. After that, the processing of the air conditioning system 1 returns to step S103.

Next, we will explain in detail the trigger conditions, which are the requirements for performing transmission channel estimation. The trigger conditions include the following first and second requirements, and are met when either of the requirements is met.

<First Requirement>
The first requirement is when the communication state between the outdoor unit 2 and the indoor unit 3 has deteriorated. The communication state is, for example, a communication speed, a retransmission rate, an error rate, etc., and is determined by comparing each with a predetermined threshold value. For example, when the communication speed is below a corresponding threshold value, it is determined that the communication state has deteriorated. Also, when the retransmission rate and the error rate exceed the corresponding threshold value, it is determined that the communication state has deteriorated. Note that each threshold value can be set to any value, but if a strict value (for example, a smaller value for the retransmission rate and the error rate) is set, the frequency of transmission path estimation increases, so it is preferable to set the threshold value to a somewhat looser value.

<Second Requirement>
The second requirement is a change in the inverter control state. The inverter control state refers to a control state of the inverter circuit 21 (or inverter circuit 31) that drives the driving component 20 (or driving component 30) with respect to the driving component 20 (or driving component 30). For example, in the air conditioning system 1, when a change in the set temperature, a change in the wind speed, or the like occurs, the rotation speed of the compressor and the fan is changed, and thus a change in the inverter control state occurs.

When the set temperature is changed, the outdoor unit 2 may change the rotation speed of the compressor, which is the driving component 20, in stages to the target rotation speed, causing the control state of the inverter circuit 21 to change in stages. In this case, if it is determined that the second requirement has occurred each time the inverter control state changes, transmission path estimation will be repeated in a short period of time. Therefore, in such a case, it may be determined that the inverter control state has changed when the inverter circuit 21 changes the compressor rotation speed to the target rotation speed.

As described above, according to the air conditioning system 1 of this embodiment, a multicarrier signal is generated using an optimal tone map based on the evaluation results of the signal quality for each subcarrier, and communication is performed between the outdoor unit 2 and the indoor unit 3. This enables communication with reduced effects of noise.

In addition, because transmission path estimation is performed at an appropriate timing limited to when the communication state deteriorates or when a change occurs in the inverter control state, the frequency with which transmission path estimation is performed is reduced. As a result, the impact on data communication traffic in the air conditioning system 1 can be reduced, and a decrease in communication speed can be suppressed.

In addition, when both the first and second requirements are met, the transmission path estimation necessity determination unit 41 may determine that the trigger condition is met and that it is necessary to perform transmission path estimation.

In addition to the first and second requirements, the transmission channel estimation necessity determination unit 41 may determine that it is necessary to perform transmission channel estimation at an appropriate timing for the purpose of initializing the tone map, such as when the air conditioning system 1 starts up, or may determine that it is necessary to perform transmission channel estimation when a long time (e.g., three hours or more) has passed since the last transmission channel estimation was performed, and a trigger condition is met.

(Embodiment 2)
Next, a description will be given of a second embodiment of the present disclosure. In the following description, components and the like common to the first embodiment will be denoted by the same reference numerals, and description thereof will be omitted.

Figure 8 is a block diagram showing the functional configuration of the control circuit 22 and the control circuit 32 provided in the outdoor unit 2 and the indoor unit 3, respectively, in embodiment 2. Note that the functional configuration of the communication circuit 23 and the communication circuit 33 in this embodiment is the same as in embodiment 1.

As shown in FIG. 8, both the control circuit 22 and the control circuit 32 include a normal control unit 40, a transmission path estimation necessity determination unit 41A, and a learning unit 42. The normal control unit 40 is a functional unit for controlling the general operation of the inverter circuit 21 (or inverter circuit 31) and the communication circuit 23 (or communication circuit 33).

The transmission channel estimation necessity determination unit 41A is an example of a transmission channel estimation necessity determination means according to the present disclosure. Similar to the transmission channel estimation necessity determination unit 41 of the first embodiment, the transmission channel estimation necessity determination unit 41A determines whether or not it is necessary to perform transmission channel estimation by determining whether or not trigger conditions (first requirement, second requirement), which are requirements for performing transmission channel estimation, are satisfied.

The learning unit 42 is an example of a learning means according to the present disclosure. The learning unit 42 learns, by actual measurement, time periods during which the communication state between the outdoor unit 2 and the indoor unit 3 is likely to deteriorate, or time periods during which changes are likely to occur in the inverter control state of the outdoor unit 2 or the indoor unit 3. The learning unit 42 outputs time period data indicating the learned time periods as a result of the learning.

In this embodiment, the trigger condition further includes, as a third requirement, the arrival of the execution time of the transmission channel estimation based on the time zone data output by the learning unit 42. The execution time of the transmission channel estimation is a time included in the time zone indicated by the time zone data, and is set under any condition by the transmission channel estimation necessity determination unit 41A. For example, the execution time of the transmission channel estimation may be the start time of the learned time zone, or may be a time a predetermined time has elapsed since the start time.

When any of the first to third requirements is met, the transmission path estimation necessity determination unit 41A determines that the trigger condition is met, determines that it is necessary to perform transmission path estimation, and instructs the communication circuit 23 (or communication circuit 33) to perform transmission path estimation.

As described above, according to the air conditioning system 1 of this embodiment, a multicarrier signal is generated using an optimal tone map based on the evaluation results of the signal quality for each subcarrier, and communication is performed between the outdoor unit 2 and the indoor unit 3. This enables communication with reduced effects of noise.

In addition, when the communication state deteriorates, when there is a change in the inverter control state, or when the transmission path estimation is performed at an appropriate timing limited to time periods when the communication state is likely to deteriorate or when the inverter control state is likely to change, the frequency of execution of the transmission path estimation is reduced, and as a result, the impact on data communication traffic in the air conditioning system 1 can be reduced, and a decrease in communication speed can be suppressed.

The transmission path estimation necessity determination unit 41A may determine that the trigger condition is met and that it is necessary to perform transmission path estimation when two or more of the first to third requirements are met.

In addition to the first to third requirements, the transmission channel estimation necessity determination unit 41A may determine that it is necessary to perform transmission channel estimation at an appropriate timing for the purpose of initializing the tone map, such as when the air conditioning system 1 starts up, or may determine that it is necessary to perform transmission channel estimation when a long time (e.g., three hours or more) has passed since the last transmission channel estimation was performed, and a trigger condition is met.

(Embodiment 3)
Next, a third embodiment of the present disclosure will be described. In the following description, components and the like common to the first embodiment will be denoted by the same reference numerals, and description thereof will be omitted.

Figure 9 is a diagram showing the overall configuration of air conditioning system 1A in embodiment 3. Like air conditioning system 1 in embodiment 1, air conditioning system 1A is a system that is installed in a building such as a building or a store and performs air conditioning within the building, and includes an outdoor unit 2, one or more indoor units 3A, and a remote control device 5. Air conditioning system 1A is an example of an air conditioning system according to the present disclosure.

The outdoor unit 2 and each indoor unit 3A are connected to a communication line 4 for communication by multicarrier signals. The outdoor unit 2 and each indoor unit 3A are also connected via refrigerant piping (not shown) for circulating refrigerant. If communication by multicarrier signals is possible, communication between the outdoor unit 2 and each indoor unit 3A may be performed wirelessly.

The hardware configuration of the outdoor unit 2 in this embodiment is the same as that of the outdoor unit 2 in embodiment 1 (see FIG. 2). The indoor unit 3A is an example of an indoor unit according to the present disclosure, and includes the same hardware configuration as the indoor unit 3 in embodiment 1 (see FIG. 3), and further includes a communication circuit (not shown) for communicating with the remote control device 5 via a dedicated communication line 6.

The remote control device 5 is an example of a remote control device according to the present disclosure. The remote control device 5 is a user interface for receiving air conditioning-related operations from a user, and although none of these are shown, includes a communication interface for communicating with the indoor unit 3A via a communication line 6, a display device such as a liquid crystal display or an organic EL (Electro Luminescence) display, an input device for receiving input operations from the user, a CPU for overall control of the remote control device 5, a ROM, a RAM, and a readable/writable non-volatile semiconductor memory such as an EEPROM or a flash memory.

When a user performs an operation related to air conditioning (e.g., changing the set temperature, changing the fan speed, etc.) via the remote control device 5, a communication frame based on that operation is sent to the indoor unit 3A, and the operation content indicated in that communication frame is notified from the indoor unit 3A to the outdoor unit 2. As a result, the air conditioning system 1A operates in accordance with the user's operation content.

Figure 10 is a block diagram showing the functional configuration of the control circuit 22 and the control circuit 32 provided in the outdoor unit 2 and the indoor unit 3, respectively, in embodiment 3. Note that the functional configuration of the communication circuit 23 and the communication circuit 33 in this embodiment is the same as in embodiment 1.

As shown in FIG. 10, both the control circuit 22 and the control circuit 32 include a normal control unit 40 and a transmission path estimation necessity determination unit 41B. The normal control unit 40 is a functional unit for controlling the general operation of the inverter circuit 21 (or the inverter circuit 31) and the communication circuit 23 (or the communication circuit 33).

The transmission path estimation necessity determination unit 41B is an example of a transmission path estimation necessity determination means according to the present disclosure. The transmission path estimation necessity determination unit 41B determines whether or not it is necessary to perform transmission path estimation by determining whether or not the following trigger condition, which is a requirement for performing transmission path estimation, is satisfied.

In this embodiment, the trigger condition includes the first requirement as in the first embodiment, and further includes a fourth requirement. The fourth requirement is when a setting change related to air conditioning (change in set temperature, change in air speed, etc.) is made by a user operating the remote control device 5. When a setting change related to air conditioning is made, a change occurs in the inverter control state of the inverter circuit 21 (or inverter circuit 31).

When either the first or fourth requirement is met, the transmission path estimation necessity determination unit 41B determines that the trigger condition is met, determines that it is necessary to perform transmission path estimation, and instructs the communication circuit 23 (or the communication circuit 33) to perform transmission path estimation.

As described above, according to the air conditioning system 1A of this embodiment, a multicarrier signal is generated using an optimal tone map based on the evaluation results of the signal quality for each subcarrier, and communication is performed between the outdoor unit 2 and the indoor unit 3A. This enables communication with reduced effects of noise.

In addition, because transmission path estimation is performed at appropriate times limited to when the communication state deteriorates or when changes are made to the air conditioning settings, the frequency with which transmission path estimation is performed is reduced. As a result, the impact on data communication traffic in the air conditioning system 1A can be reduced, and a decrease in communication speed can be suppressed.

The transmission path estimation necessity determination unit 41B may determine that the trigger condition is met and that it is necessary to perform transmission path estimation when both the first and fourth requirements are met.

In addition to the first and fourth requirements, the transmission channel estimation necessity determination unit 41B may determine that it is necessary to perform transmission channel estimation at an appropriate timing for the purpose of initializing the tone map, such as when the air conditioning system 1A starts up, or may determine that it is necessary to perform transmission channel estimation when a long time (e.g., three hours or more) has passed since the last transmission channel estimation was performed, and a trigger condition is met.

The outdoor unit 2 and the remote control device 5 may be connected via a dedicated communication line 6, or the remote control device 5 may be connected to the communication line 4.

In addition, each of the control circuit 22 and the control circuit 32 may further include a learning unit 42 of the second embodiment, and the transmission channel estimation necessity determination unit 41B may determine that the trigger condition is met and that it is necessary to perform transmission channel estimation when any one of the first requirement, the third requirement, and the fourth requirement is met, or may determine that the trigger condition is met and that it is necessary to perform transmission channel estimation when two or more of the first requirement, the third requirement, and the fourth requirement are met.

(Embodiment 4)
Next, a fourth embodiment of the present disclosure will be described. In the following description, components and the like common to the first embodiment will be denoted by the same reference numerals, and description thereof will be omitted.

Figure 11 is a diagram showing the overall configuration of air conditioning system 1B in embodiment 4. Like air conditioning system 1 in embodiment 1, air conditioning system 1B is a system that is installed in a building such as a building or a store and provides air conditioning within the building, and includes an outdoor unit 2A and one or more indoor units 3. Air conditioning system 1B is an example of an air conditioning system according to the present disclosure.

The outdoor unit 2A and each indoor unit 3 are connected to a communication line 4 for communication by multicarrier signals. The outdoor unit 2A and each indoor unit 3 are also connected via refrigerant piping (not shown) for circulating the refrigerant. If communication by multicarrier signals is possible, the outdoor unit 2A and each indoor unit 3 may be configured to communicate wirelessly.

The outdoor unit 2A is an example of an outdoor unit according to the present disclosure, and includes the same hardware configuration as the outdoor unit 2 of the first embodiment (see FIG. 2), and further includes a communication circuit (not shown) for communicating with the inverter device 7 via a dedicated communication line 8. The hardware configuration of the indoor unit 3 in this embodiment is the same as that of the indoor unit 3 of the first embodiment (see FIG. 3).

The inverter device 7 is a device that includes a drive component, an inverter circuit that drives the drive component, and a control circuit that controls the inverter circuit, and is, for example, a ventilation device or a water heater. When a change occurs in the inverter control state of the inverter device 7, the inverter device 7 notifies the outdoor unit 2A of the change.

Figure 12 is a block diagram showing the functional configuration of the control circuit 22 and the control circuit 32 provided in the outdoor unit 2A and the indoor unit 3, respectively, in embodiment 4. Note that the functional configuration of the communication circuit 23 and the communication circuit 33 in this embodiment is the same as in embodiment 1.

As shown in FIG. 12, both the control circuit 22 and the control circuit 32 include a normal control unit 40 and a transmission path estimation necessity determination unit 41C. The normal control unit 40 is a functional unit for controlling the general operation of the inverter circuit 21 (or the inverter circuit 31) and the communication circuit 23 (or the communication circuit 33).

The transmission path estimation necessity determination unit 41C is an example of a transmission path estimation necessity determination means according to the present disclosure. The transmission path estimation necessity determination unit 41C determines whether or not it is necessary to perform transmission path estimation by determining whether or not the following trigger conditions, which are requirements for performing transmission path estimation, are satisfied.

In this embodiment, the trigger conditions include the first and second requirements similar to those in the first embodiment, and further include a fifth requirement. The fifth requirement is when the inverter control state of the inverter device 7 changes.

When any one of the first, second, and fifth requirements is met, the transmission path estimation necessity determination unit 41C determines that the trigger condition is met, determines that it is necessary to perform transmission path estimation, and instructs the communication circuit 23 (or the communication circuit 33) to perform transmission path estimation.

As described above, according to the air conditioning system 1B of this embodiment, a multicarrier signal is generated using an optimal tone map based on the evaluation results of the signal quality for each subcarrier, and communication is performed between the outdoor unit 2A and the indoor unit 3. This enables communication with reduced effects of noise.

In addition, because transmission path estimation is performed at appropriate timing limited to when the communication state deteriorates, when there is a change in the inverter control state in the air conditioning system 1B, or when the inverter control state of the inverter device 7 changes, the frequency with which transmission path estimation is performed is reduced. As a result, the impact on data communication traffic in the air conditioning system 1B can be reduced, and a decrease in communication speed can be suppressed.

The transmission path estimation necessity determination unit 41C may determine that the trigger condition is met and that it is necessary to perform transmission path estimation when two or more of the first, second, and fifth requirements are met.

In addition, the transmission channel estimation necessity determination unit 41C may determine that transmission channel estimation needs to be performed at an appropriate timing for the purpose of initializing the tone map, for example, when the air conditioning system 1B starts up, in addition to the first, second, and fifth requirements, or may determine that a trigger condition is met and that transmission channel estimation needs to be performed when a long time (for example, three hours or more) has passed since the last transmission channel estimation was performed.

The indoor unit 3 and the inverter device 7 may be connected via a dedicated communication line 8, or the inverter device 7 may be connected to the communication line 4. When the indoor unit 3 and the inverter device 7 are connected via the communication line 8, the notification from the inverter device 7 that a change has occurred in the inverter control state is also notified to the outdoor unit 2A via the indoor unit 3.

In addition, each of the control circuit 22 and the control circuit 32 may further include a learning unit 42 of the second embodiment, and the transmission channel estimation necessity determination unit 41C may determine that the trigger condition is met and that it is necessary to perform transmission channel estimation when any one of the first requirement to the third requirement and the fifth requirement is met, or may determine that the trigger condition is met and that it is necessary to perform transmission channel estimation when two or more of the first requirement to the third requirement and the fifth requirement are met.

Alternatively, the transmission path estimation necessity determination unit 41C may determine that the trigger condition is met and that it is necessary to perform transmission path estimation when any one of the first requirement, the fourth requirement, and the fifth requirement is met, or may determine that the trigger condition is met and that it is necessary to perform transmission path estimation when two or more of the first requirement, the fourth requirement, and the fifth requirement are met.

This disclosure is not limited to the above-described embodiments, and various modifications are of course possible without departing from the spirit of this disclosure.

1, 1A, 1B Air conditioning system, 2, 2A Outdoor unit, 3, 3A Indoor unit, 4, 6, 8 Communication line, 5 Remote control device, 7 Inverter device, 20, 30 Drive parts, 21, 31 Inverter circuit, 22, 32 Control circuit, 23, 33 Communication circuit, 40 Normal control unit, 41, 41A, 41B, 41C Transmission path estimation necessity determination unit, 50 Communication control unit, 51 Transmission unit, 52 Reception unit, 510 Modulation unit, 511 Tone map control unit, 512 Frame generation unit, 513 Inverse wavelet transformation unit, 520 Wavelet transformation unit, 521 Data extraction unit, 522 Transmission path estimation unit, 523 Demodulation unit

Claims (9)

An air conditioning system comprising an outdoor unit and an indoor unit, the outdoor unit and the indoor unit communicating with each other via a multicarrier signal,
a transmission path estimation necessity determination means for determining whether or not it is necessary to perform transmission path estimation;
a transmission channel estimation means for executing a transmission channel estimation to evaluate a signal quality of each subcarrier of the multicarrier signal when it is determined by the transmission channel estimation necessity determination means that it is necessary to execute the transmission channel estimation, and for determining a tone map;
The air conditioning system, wherein the transmission path estimation necessity determining means determines that it is necessary to perform transmission path estimation when an inverter control state of the outdoor unit or the indoor unit changes. An air conditioning system comprising an outdoor unit and an indoor unit, the outdoor unit and the indoor unit communicating with each other via a multicarrier signal,
a transmission path estimation necessity determination means for determining whether or not it is necessary to perform transmission path estimation;
a transmission channel estimation means for performing a transmission channel estimation to evaluate a signal quality of each subcarrier of the multicarrier signal and determine a tone map when the transmission channel estimation necessity determination means determines that it is necessary to perform the transmission channel estimation;
A learning means for learning a time period during which a change in the inverter control state of the outdoor unit or the indoor unit is likely to occur,
The air conditioning system, wherein the transmission channel estimation necessity determining means determines that it is necessary to perform transmission channel estimation when a set time arrives within the range of the time period obtained by the learning means. An air conditioning system comprising an outdoor unit, an indoor unit, and a remote control device, the outdoor unit and the indoor unit communicating with each other via a multicarrier signal,
a transmission path estimation necessity determination means for determining whether or not it is necessary to perform transmission path estimation;
a transmission channel estimation means for executing a transmission channel estimation to evaluate a signal quality of each subcarrier of the multicarrier signal when it is determined by the transmission channel estimation necessity determination means that it is necessary to execute the transmission channel estimation, and for determining a tone map;
The air conditioning system, wherein the transmission channel estimation necessity determining means determines that it is necessary to perform transmission channel estimation when a setting related to air conditioning is changed by a user's operation via the remote control device. An air conditioning system comprising an outdoor unit and an indoor unit, the outdoor unit and the indoor unit communicating with each other by a multicarrier signal, and connected to an inverter device different from both the outdoor unit and the indoor unit so as to be able to communicate with each other,
a transmission path estimation necessity determination means for determining whether or not it is necessary to perform transmission path estimation;
a transmission channel estimation means for executing a transmission channel estimation to evaluate a signal quality of each subcarrier of the multicarrier signal when it is determined by the transmission channel estimation necessity determination means that it is necessary to execute the transmission channel estimation, and for determining a tone map;
The air conditioning system, wherein the transmission path estimation necessity determining means determines that it is necessary to perform transmission path estimation when an inverter control state of the inverter device changes. the outdoor unit is provided with the transmission path estimation necessity determination means,
The air conditioning system according to claim 1 , wherein the indoor unit is provided with the transmission channel estimating means. A transmission path estimation method executed by an air conditioning system including an outdoor unit and an indoor unit, the outdoor unit and the indoor unit communicating with each other using a multicarrier signal, comprising:
A transmission path estimation method comprising: performing transmission path estimation for evaluating signal quality for each subcarrier of the multicarrier signal when an inverter control state of the outdoor unit or the indoor unit changes; and determining a tone map. A transmission path estimation method executed by an air conditioning system including an outdoor unit and an indoor unit, the outdoor unit and the indoor unit communicating with each other using a multicarrier signal, comprising:
learning a time period during which a change in the inverter control state of the outdoor unit or the indoor unit is likely to occur;
a transmission channel estimation method for performing a transmission channel estimation to evaluate a signal quality for each subcarrier of the multicarrier signal at a set time within the range of the time period obtained by the learning, and determining a tone map. A transmission channel estimation method executed by an air conditioning system including an outdoor unit, an indoor unit, and a remote control device, the outdoor unit and the indoor unit communicating with each other using a multicarrier signal, comprising:
A transmission path estimation method for performing transmission path estimation to evaluate the signal quality of each subcarrier of the multicarrier signal when a user changes settings related to air conditioning through operation of the remote control device, and determining a tone map. A transmission path estimation method executed by an air conditioning system comprising an outdoor unit and an indoor unit, the outdoor unit and the indoor unit communicating with each other using a multicarrier signal, and the air conditioning system being communicatively connected to an inverter device different from both the outdoor unit and the indoor unit, comprising:
A transmission path estimation method, comprising: performing transmission path estimation for evaluating signal quality for each subcarrier of the multicarrier signal when an inverter control state of the inverter device changes; and determining a tone map.

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