Dynamic distribution method for communication time periods of indoor unit and outdoor unit of air conditioner

Abstract

The invention provides a dynamic distribution method for communication time periods of indoor units and outdoor units of an air conditioner, and relates to the field of air conditioner multiplexing communication, which comprises the following steps of: sharing the same communication channel by the outdoor units and a plurality of indoor units, dividing the communication time of the communication channel into a plurality of time frames with fixed lengths, dividing each time frame into an uplink time slot and a downlink time slot, dividing the uplink time slot into a plurality of sub time slots with fixed lengths; at the beginning, sub-time slots with corresponding numbers are distributed to each internal unit, and a time slot distribution table is generated; each inner unit sends data to the outer unit in sequence according to the sub-time slots of the corresponding numbers, and the outer unit sends the data to the inner units through the downlink time slots; and in other communication periods of subsequent frames, the outdoor unit can regenerate a new time slot allocation table, and the indoor unit executes data sending operation according to the new time slot allocation table. According to the method, the communication time periods between the multiple indoor units and the single outdoor unit of the air conditioner group control system are dynamically allocated, and the problem that the multiple indoor units send data at the same time, so that communication conflicts occur, and instructions are lost or delayed is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of air conditioner multiplex communication, and particularly relates to a method for dynamically allocating communication time periods between an indoor unit and an outdoor unit of an air conditioner. Background Art

[0002] In an air conditioner group control system, such as a multi-connected unit system, generally an outdoor unit as a single host is connected to multiple indoor units. The multiple indoor units need to frequently interact with the outdoor unit as a single host. For example, the indoor unit uploads user settings and real-time status (such as temperature requests, compressor status, etc.) to the outdoor unit, and the outdoor unit allocates resources according to global information, such as dynamically adjusting the output power to match the total load of all indoor units, avoiding frequent start-stop or overload, and improving the comprehensive energy efficiency ratio. Another example is that the indoor and outdoor units report faults to each other in real time to trigger a protection mechanism (such as shutdown, frequency reduction) to prevent the spread of faults.

[0003] The data communication transmission between the outdoor unit and the indoor unit is generally divided into wired and wireless. Wired communication includes RS485 or CAN bus that supports master-slave communication of multiple nodes (indoor units) and a single host (outdoor unit). However, when the number of indoor units is relatively large and the communication distance is relatively long, affected by the installation environment, the cost is relatively high, the installation is complex, and the quality level, distance, and technical ability of the installation personnel of the communication line all affect the communication quality. Wireless connection does not require the use of communication lines, and a wireless module is used between the indoor and outdoor units to maintain communication, with simple installation and low cost.

[0004] However, for the wireless communication method, there are the following problems:

[0005] a. Signal collision: Multiple indoor units send data simultaneously, resulting in communication conflicts and causing instruction loss or delay;

[0006] b. Resource competition: The outdoor unit needs to respond to requests from multiple indoor units. If the scheduling is improper, it will lead to confusion in response priorities;

[0007] c. Increased energy consumption: Frequent retransmission of data exacerbates the system power consumption and reduces the energy efficiency;

[0008] Therefore, how to solve the above problems has become an important research topic for the current communication between indoor and outdoor units of air conditioners. Summary of the Invention

[0009] In view of the problems raised in the background art, the present invention proposes a method for dynamically allocating communication time periods between an indoor unit and an outdoor unit of an air conditioner.

[0010] To achieve this purpose, the present invention adopts the following technical solutions:

[0011] A method for dynamically allocating communication time periods between an indoor unit and an outdoor unit of an air conditioner, including using the same wireless frequency band for the outdoor unit and multiple indoor units in an air conditioner group control system to share the same communication channel, dividing the communication time of the communication channel into multiple time frames of fixed length, dividing each time frame into an uplink time slot and a downlink time slot, dividing the uplink time slot into multiple sub-time slots of fixed length, where the uplink time slot is used for multiple indoor units to send data to the outdoor unit, and the downlink time slot is used for the outdoor unit to send data to multiple indoor units, including:

[0012] Step A: When dividing the uplink time slot into sub-time slots, the number of sub-time slots is greater than or equal to the number of indoor units;

[0013] Step B: Initially, the outdoor unit sequentially numbers each sub-time slot, assigns the sub-time slot with the corresponding number to each indoor unit according to the SN code of each indoor unit and generates a time slot allocation table, and the outdoor unit broadcasts the time slot allocation table to all indoor units through the downlink time slot;

[0014] Step C: During the communication cycle of the current frame, each indoor unit sends data to the outdoor unit in sequence according to the corresponding numbered sub-time slot, and the outdoor unit sends data to all indoor units in the form of broadcast according to all indoor unit addresses through the downlink time slot or sends data to the corresponding indoor unit in the form of unicast according to the target indoor unit address;

[0015] Step D: During the communication cycles of subsequent frames, the outdoor unit reallocates the sub-time slots of all indoor units according to the communication data volume or communication priority of all indoor units and generates a new time slot allocation table to broadcast to all indoor units, and all indoor units perform data sending operations according to the new time slot allocation table;

[0016] Step E: When a new indoor unit is connected to the air conditioner group control system, steps A to D are executed again.

[0017] Preferably, obtain the online operation status of all indoor units to determine the communication status of all sub-time slots in the current frame, mark the sub-time slots corresponding to the online operating indoor units as static time slots in a busy state, and mark the sub-time slots corresponding to the non-online operating indoor units as dynamic time slots in an idle state.

[0018] Preferably, at least one sub-time slot is divided in the uplink time slot as a shared contention time slot, and the shared contention time slot is used for an indoor unit to initiate an additional request for the communication requirement of the next frame to the outdoor unit by preempting the shared contention time slot or for an indoor unit to send additional data again;

[0019] Dividing at least one shared contention time slot includes:

[0020] Operation 1: In addition to dividing the number of sub-time slots required by the indoor units in the uplink time slot, at least one sub-time slot needs to be divided as a shared contention time slot, and the numbers of the shared contention time slots are arranged at the end;

[0021] OR operation two: If there are dynamic time slots in the idle state in the current frame, based on operation one, the dynamic time slots in the idle state are used as shared contention time slots.

[0022] Preferably, the additional data is emergency warning data or fault data;

[0023] After the outdoor unit receives an additional request or additional data in the current frame, it reallocates the sub-time slots of all indoor units according to the additional request or additional data, generates a new time slot allocation table for the communication cycle of subsequent frames, and sends the new time slot allocation table to all indoor units through the downlink time slot of the current frame. All indoor units perform data transmission operations according to the new time slot allocation table in the communication cycle of subsequent frames.

[0024] Preferably, when all indoor units are online and running, each indoor unit sends data to the outdoor unit according to the corresponding static time slot;

[0025] When there are indoor units that are not online and running, if the current indoor unit itself needs to send this data, and this data does not include additional data or additional requests, then it is judged whether there are N dynamic time slots in front of the static time slot corresponding to the current indoor unit and there are no other static time slots. N > a, where a represents the number of sub-time slots reserved for other indoor units to preempt. If so, the nth dynamic time slot is allocated to the current indoor unit to send data, a + 1 ≤ n ≤ N, and at the same time, the static time slot corresponding to the current indoor unit is reserved. If not, the current indoor unit sends data according to the corresponding static time slot;

[0026] Or it is judged whether there are N dynamic time slots between the static time slot corresponding to the current indoor unit and another static time slot in front of it. N > a, where a represents the number of sub-time slots reserved for other indoor units to preempt. If so, the nth dynamic time slot between the two static time slots is allocated to the current indoor unit to send data, a + 1 ≤ n ≤ N, and at the same time, the static time slot corresponding to the current indoor unit is reserved. If not, the current indoor unit sends data according to the corresponding static time slot.

[0027] Preferably, when the nth dynamic time slot allocated to the current indoor unit to send data is preempted by other indoor units as a shared contention time slot to send additional requests or additional data, the (n + 1)th dynamic time slot is allocated to the current indoor unit. If the (n + 1)th dynamic time slot is also preempted by other indoor units as a shared contention time slot to send additional requests or additional data, the (n + 2)th dynamic time slot is allocated to the current indoor unit, and so on... until there are no dynamic time slots available for the current indoor unit to send this data, the current indoor unit sends data according to the corresponding static time slot.

[0028] Preferably, all sub-time slots divided by the uplink time slot are embedded with guard times, and the interval lengths of the guard times corresponding to each sub-time slot are the same;

[0029] The calculation formula for the protection time is as follows:

[0030] T = T mpd + T ce + T pre ;

[0031] Wherein, T represents the protection time, T mpd represents the maximum propagation delay, T ce represents the clock error, T pre represents the pre-allocated time, and the total length of the pre-allocated time of all indoor units is the length of one sub-slot.

[0032] Preferably, when the outdoor unit receives data sent from all indoor units and receives additional data or additional requests sent from different indoor units within consecutive communication cycles of multiple frames, the outdoor unit shortens the protection time of each sub-slot, combines the pre-allocated time in the original protection time to divide out one more new sub-slot, uses the new sub-slot as a shared contention slot, re-formulates a new time slot allocation table and broadcasts it to all indoor units through the downlink time slot;

[0033] The calculation formula for the shortened protection time is as follows:

[0034] T = T mpd + T ce .

[0035] Preferably, when the outdoor unit sends data to the indoor unit through the downlink time slot, it further includes:

[0036] Dividing the downlink time slot into sub-slots with the same number as the indoor units, and allocating each sub-slot to the corresponding indoor unit, so that the outdoor unit sends specified data for different indoor units in different sub-slots.

[0037] Preferably, when the outdoor unit sends data to the indoor unit through the downlink time slot in the current frame, it will attach a start identifier at the frame start point, and all indoor units align their clocks with the start identifier as the synchronization signal.

[0038] The beneficial effects of the present invention compared with the prior art:

[0039] The present invention dynamically allocates communication time periods between multiple indoor units and a single outdoor unit in an air conditioner group control system, including dynamically adjusting the structure of a time frame according to actual requirements, using idle time slots as shared contention time slots for other indoor units to compete for preemption, dynamically scheduling the use of idle time slots in accordance with the principle of avoiding shared contention time slots to prevent waste of time slot resources. At the same time, a pre-allocated time is added to the guard time of each time slot, and the pre-allocated time can be used to form the length of a time slot to add new time slots, effectively solving the problem of communication conflicts caused by multiple indoor units sending data simultaneously, resulting in lost or delayed instructions, solving the problem that the outdoor unit needs to respond to requests from multiple indoor units, and improper scheduling may lead to confusion in response priorities, and solving the problem that frequent retransmission of data by indoor units exacerbates system power consumption and reduces energy efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a flowchart of a method for dynamically allocating communication time periods between an indoor unit and an outdoor unit of the present invention;

[0041] Figure 2 is a communication schematic diagram of multiple time frames (downlink time slots are not divided into multiple sub-time slots) in an embodiment of the present invention;

[0042] Figure 3 is a communication schematic diagram of the current time frame (downlink time slots are divided into multiple sub-time slots) in an embodiment of the present invention;

[0043] Figure 4 is a communication schematic diagram of dividing at least one shared contention time slot in an embodiment of the present invention;

[0044] Figure 5 is a communication schematic diagram of other indoor units scheduling the use of other idle sub-time slots in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0045] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0046] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0047] In the description and claims of the present invention, and in the above-mentioned drawings, terms such as "first" and "second" are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, device, product or terminal that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products or terminals.

[0048] Reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present invention. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0049] In an air-conditioning group control system, such as a multi-split system, multiple indoor units (indoor machines) and an outdoor unit (outdoor machine) need to frequently exchange data. The essence of the communication of such an air-conditioning group control system is "demand allocation and global optimization". The indoor units upload "demands" and "statuses", and the outdoor unit, as a "quasi central processing unit", coordinates information such as refrigerant flow rate, power output, and fault handling, and finally realizes efficient, stable, and intelligent operation. For example, the data and control logic transmitted in the interaction between the indoor unit and the outdoor unit include:

[0050] 1. The indoor unit sends user-set data

[0051] Basic instructions: power on / off, mode (cooling / heating / dehumidifying / air supply), set temperature (such as 18°C), wind speed (low / medium / high / automatic), swing angle; Special functions: sleep mode (automatic temperature adjustment), energy-saving mode (limiting maximum load), self-cleaning request.

[0052] Response of the outdoor unit:

[0053] According to the mode, switch the running direction of the compressor (a four-way valve is required for heating), calculate the target superheat / subcooling degree according to the set temperature, and adjust the opening of the electronic expansion valve; The wind speed affects the air volume of the indoor unit, and the outdoor unit synchronously adjusts the fan speed (such as increasing the condenser heat dissipation at high wind speed).

[0054] 2. The indoor unit sends real-time status data

[0055] Indoor environment: current room temperature (collected by a thermocouple / infrared sensor), humidity (used for dehumidifying mode judgment); Equipment status: indoor unit fan speed, electronic expansion valve opening, filter clogging signal (sensor or running time estimation).

[0056] Response of the outdoor unit:

[0057] Calculate the load of a single indoor unit (such as the temperature difference between the room temperature and the set value multiplied by the air volume), and adjust the compressor frequency after accumulating the loads of all indoor units (such as running at a low frequency when the total load is low); when the filter is dirty or blocked, the outdoor unit can reduce the refrigerant flow rate or prompt the user to clean it to avoid a decrease in efficiency caused by insufficient air volume.

[0058] 3. The indoor unit sends fault and protection data

[0059] Fault codes: indoor unit sensor failure (such as a short circuit of the room temperature sensor), motor abnormality, communication interruption. Protection signals: overheat protection (the temperature of the indoor unit heat exchanger is too high), anti-freezing protection (the evaporator temperature ≤ 0°C).

[0060] Response of the outdoor unit:

[0061] After receiving the fault code, trigger local or global protection: for example, when a single indoor unit fails, close the solenoid valve of that indoor unit, and the other indoor units continue to operate; if the outdoor unit detects high-pressure protection (such as refrigerant leakage), then all indoor units stop.

[0062] When multiple indoor units send data to the outdoor unit, there may be a problem of signal collision. When the outdoor unit sends data or commands to multiple indoor units, there may be a problem of improper scheduling and incorrect response to priority requests. In actual R & D, it is found that the TDMA (Time Division Multiple Access) communication technology allows multiple devices to use the same frequency for communication in different time slots, that is, the communication time is divided into multiple time frames of fixed length, and each time frame contains multiple time slots. Each device is assigned one or more time slots for sending and receiving data within that time slot, which can isolate the transmissions of different devices in time, reduce the mutual interference between devices, and through time slot allocation, the resource allocation can be flexibly adjusted according to the device requirements to meet the communication needs of different devices. And how to optimize the TDMA technology according to the actual needs of the air conditioner group control system to adapt to the frequent data interaction between multiple indoor units and a single outdoor unit is a current direction of air conditioner communication R & D. Based on this, this application proposes a method for dynamically allocating communication time periods between an air conditioner indoor unit and an outdoor unit;

[0063] Specifically, as Figure 1 and Figure 2 shown, the outdoor unit and multiple indoor units in the air conditioner group control system use the same wireless frequency band to share the same communication channel, divide the communication time of the communication channel into multiple time frames of fixed length, divide each time frame into an uplink time slot and a downlink time slot, divide the uplink time slot into multiple sub-time slots of fixed length, the uplink time slot is used for multiple indoor units to send data to the outdoor unit, and the downlink time slot is used for the outdoor unit to send data to multiple indoor units;

[0064] The outdoor unit and multiple indoor units need to be connected to the same wireless frequency band, aiming to ensure that both the outdoor unit and indoor units can share the same communication channel, dynamically allocate communication time slots, and ensure that each device exclusively occupies the channel within the specified time window to avoid collisions. In this embodiment, the time frame is a complete communication cycle that includes all time slots. The length of the time frame needs to balance real-time performance and efficiency, avoiding problems such as delays caused by an overly long time frame or insufficient time slots due to an overly short time frame. Specifically, the length of the time frame needs to be set according to the actual usage requirements of the air conditioner, such as the number of indoor units, the amount of data exchanged between the indoor and outdoor units, the online operation status of the indoor units, the communication rate, etc. For example, during the off-peak season of air conditioner use, each sub-time slot of 4 indoor units is allocated 50 ms (milliseconds), and the downlink time slot of the outdoor unit is allocated 40 ms. Then, the cycle of one frame is 200 ms for the uplink time slot, 40 ms for the downlink time slot, and 240 ms in total. After reserving the optimization cycle length, we optimize the cycle length of one frame to 250 ms; for the peak season of air conditioner use, such as in summer, each indoor unit in a group of 10 indoor units needs to send at least 100 bytes of uplink data packets per frame, and the downlink instructions of the outdoor unit are at least 50 bytes. If the communication rate is 9600 bps for every 8 bytes, then the length of the uplink time slot of one frame is 10 units × 100 bytes × 8 bit / 9600 bps ≈ 833 ms. Therefore, the uplink time slot is allocated 900 ms (including the protection time of 7 ms for each sub-time slot corresponding to each indoor unit). If there is no sub-time slot for the downlink time slot, the length of a single downlink time slot is half of the length of a single sub-time slot of the uplink time slot, that is, 50 ms. So, the length of one frame is 900 ms (uplink) + 50 ms (downlink) = 950 ms, and after optimization, it is a 1-second cycle;

[0065] Further, a sub-time slot is a fixed time period allocated to a single device for exclusive data transmission. If the cycle is 100 ms, each of the 5 indoor units is allocated a 20-ms time slot, and each indoor unit only sends data during its exclusive time slot. For example, 0 - 20 ms is the sending period of the first indoor unit, 20 - 40 ms is the sending period of the second indoor unit...

[0066] The specific implementation of this method is as follows:

[0067] Step A: When dividing the uplink time slot into sub-time slots, the number of sub-time slots is greater than or equal to the number of indoor units;

[0068] The number of sub-time slots should be greater than or equal to the number of indoor units. For example, if the current number of indoor units in the air conditioner group control system is 10, then the number of sub-time slots divided from the uplink time slot is at least 10. Usually, we will add 2 more sub-time slots, that is, 12 sub-time slots, for subsequent allocation to new indoor units if new indoor units are connected to the air conditioner group control system. However, the number of additional sub-time slots cannot be too large, as it will increase the cycle length of the frame or shorten the length of each sub-time slot. Therefore, when increasing the number of sub-time slots, it needs to be designed according to the actual requirements.

[0069] Step B: Initially, the outdoor unit sequentially numbers each sub-slot, assigns the sub-slot with the corresponding number to each indoor unit according to the SN code of each indoor unit, and generates a time slot allocation table. The outdoor unit broadcasts the time slot allocation table to all indoor units through the downlink time slot.

[0070] In this embodiment, which sub-slot or in which time period each indoor unit sends data to the outdoor unit is allocated by the outdoor unit. Initially, the outdoor unit sequentially numbers each sub-slot, for example, sub-slots numbered 0-9, and assigns the sub-slot with the corresponding number to each indoor unit according to the SN code of each indoor unit to form a time slot allocation table. The reason for allocating and designating with the SN code of the indoor unit is that the electronic control board of the whole machine will be burned with SN codes, including the SN code of the indoor unit and the SN code of the outdoor unit. The outdoor unit and the indoor unit mutually store the SN codes of each other, and the SN code is unique. Allocating in this way can make each indoor unit clear its own sub-slot.

[0071] Step C: During the communication cycle of the current frame, each indoor unit sends data to the outdoor unit in sequence according to the sub-slot with the corresponding number. The outdoor unit sends data to all indoor units in the form of broadcast according to all indoor unit addresses through the downlink time slot or sends data to the corresponding indoor unit in the form of unicast according to the target indoor unit address.

[0072] For example, during the communication cycle of a frame, indoor unit A is allocated to sub-slot 0, indoor unit B is allocated to sub-slot 1, and indoor unit C is allocated to sub-slot 2. The length of each sub-slot is 20 ms. Then indoor unit A sends data in the time period of 0-20 ms, indoor unit B sends data in the time period of 20-40 ms, and indoor unit C sends data in the time period of 40-60 ms. Indoor unit B needs to wait for indoor unit A to finish sending data before sending its own data. If indoor unit A does not send data, indoor unit B still needs to wait for the time period of 0-20 ms to pass before indoor unit B can send its own data in the time period of 20-40 ms. The limitation of this rule is the setting of the TDMA technology itself to ensure that each indoor unit can not interfere with each other. However, this setting will also cause the indoor unit that needs to send data to wait for the previous sub-slot to finish, which will lead to waste of time periods. And this application also improves the problem of waste of time periods. For details, please refer to the following text.

[0073] Further, after receiving the data from the indoor unit, the outdoor unit will issue targeted instructions or control commands, etc., and then send the data to all indoor units in the form of broadcast through the downlink time slot or send the data to the corresponding indoor unit in the form of unicast. When sending data to all indoor units in the form of broadcast, the data sent is generally global instructions, such as compressor start / stop, temperature setting, mode switching, etc. When sending data to a specific indoor unit in the form of unicast, the data sent is generally a specific indoor unit control instruction, such as the opening degree of the electronic expansion valve of indoor unit A. Whether it is broadcast or unicast, it needs to be sent through the address field of the indoor unit. Therefore, the outdoor unit needs to store the address field of the indoor unit in the initial stage. Of course, the effect of unicast can also be achieved through the form of broadcast. For example, when sending "the opening degree of the electronic expansion valve of indoor unit A" to all outdoor units, all indoor units will receive and parse the instruction. After parsing, only indoor unit A will open the electronic expansion valve, and other indoor units do not need to execute. In this case, the indoor unit needs to have the function of parsing instructions.

[0074] Step D: In other communication cycles of subsequent frames, the outdoor unit reallocates the sub-time slots of all indoor units according to the communication data volume or communication priority of all indoor units and generates a new time slot allocation table to broadcast to all indoor units. All indoor units perform data sending operations according to the new time slot allocation table;

[0075] In this embodiment, the time slot allocation table formulated by the outdoor unit in the initial stage will not be used all the time. The time slot allocation table needs to be set according to the actual communication situation. For example, after running for a period of time, the outdoor unit finds that the communication data volume of indoor unit A is particularly large and the data priority of indoor unit B sent each time is much higher than that of other indoor units after counting the communication data volume and communication priority of all indoor units in the communication cycles of a period of time. Then the outdoor unit may allocate one more sub-time slot to indoor unit A and indoor unit B so that indoor unit A and indoor unit B can send data to the outdoor unit twice in the communication cycle of the current frame. When a new time slot allocation table is formed, all indoor units will execute according to the new time slot allocation table. It should be noted that after the outdoor unit of the current frame formulates the new time slot allocation table, all indoor units will execute in the next frame.

[0076] Step E: When a new indoor unit is connected to the air conditioner group control system, steps A to D are executed again.

[0077] Preferably, obtain the online operation status of all indoor units to determine the communication status of all sub-time slots in the current frame. Mark the sub-time slots corresponding to the online indoor units as static time slots in a busy state, and mark the sub-time slots corresponding to the offline indoor units as dynamic time slots in an idle state.

[0078] As mentioned above, in this solution, corresponding sub-slots are allocated to all indoor units. After each indoor unit goes online and runs, it can send data to the outdoor unit through the corresponding sub-slot. However, not all indoor units will go online and run, which makes the communication status of the sub-slots corresponding to the indoor units that do not go online and run idle. For example, indoor unit A corresponds to sub-slot 0, indoor unit B corresponds to sub-slot 1, and indoor unit C corresponds to sub-slot 2. If indoor units A and B do not go online and run, indoor unit C needs to wait for the two time periods of sub-slot 0 and sub-slot 1 to pass before it can send data using sub-slot 2, which will waste the two time periods of sub-slot 0 and sub-slot 1. Therefore, in this application, the communication status of all sub-slots in the current frame is determined based on the online running status of all indoor units. The sub-slots corresponding to the indoor units that have gone online and run are marked as static slots in a busy state, and the sub-slots corresponding to the indoor units that do not go online and run are marked as dynamic slots in an idle state. A dynamic slot means that within the communication cycle of the current frame, it can be used to be scheduled for other online indoor units to use. When the outdoor unit schedules the time slot allocation table, it only needs to synchronously set the logic allowing other indoor units to use the dynamic slot. After the indoor unit receives the time slot allocation table, it will execute the allow logic operation. The dynamic scheduling of the dynamic slot can be, for example, the shared competition slot as described below or moving the indoor unit with a later number to the dynamic slot with a previous number to send data.

[0079] Preferably, at least one sub-slot is divided in the uplink time slot as a shared competition slot, and the shared competition slot is used for the indoor unit to initiate an additional request for the communication requirement of the next frame to the outdoor unit or the indoor unit to resend additional data by preempting the shared competition slot in the current frame;

[0080] Within the communication cycle of a current frame, corresponding sub-slots are allocated to each indoor unit for the indoor unit to send data, but there will still be some problems, such as the following situations:

[0081] Situation 1: When a certain indoor unit has already sent data to the outdoor unit through its corresponding sub-slot, the sub-slot quota of this indoor unit has been used up, but this indoor unit suddenly detects faulty data or an emergency warning data and needs to send it to the outdoor unit in the current frame. However, other indoor units with subsequent numbers need to send data in the other sub-slots. Then, there is no additional sub-slot available for this indoor unit to send additional data to the outdoor unit;

[0082] Situation 2: Regarding Situation 1, it is possible that more than one indoor unit needs to send additional data to the outdoor unit;

[0083] Case 3: The length of the sub - time slot allocated to a certain indoor unit is not sufficient to support the amount of data to be sent by the indoor unit in the current frame. In this case, the indoor unit can only send part of the data to the outdoor unit. After receiving the data, the outdoor unit does not know that the data is incomplete, or the indoor unit sends an additional request during its sub - time slot and leaves the data to be sent to the next frame. In either case, an additional sub - time slot is required for the indoor unit to initiate an additional request for the communication requirements of the next frame to the outdoor unit in the current frame, that is, to inform the outdoor unit in the current frame that this indoor unit needs to occupy more sub - time slots to send data in the next frame, so that the indoor unit can report its requirements to the outdoor unit, and the outdoor unit can re - arrange the time slot allocation table;

[0084] Therefore, in either of the above cases, we need to reserve at least one shared contention time slot in the uplink time slot, so that the indoor unit can initiate an additional request for the communication requirements of the next frame to the outdoor unit in the current frame or re - send additional data. The shared contention time slot needs to be occupied by multiple indoor units in a competitive pre - emption form. In short, the indoor unit that pre - empts first can use it.

[0085] As Figure 4 shown, dividing at least one shared contention time slot includes:

[0086] Operation 1: In addition to dividing the required number of sub - time slots for the indoor units in the uplink time slot, at least one sub - time slot needs to be divided as a shared contention time slot, and the numbers of the shared contention time slots are arranged at the end;

[0087] Or Operation 2: If there are dynamic time slots in the current frame that are in an idle state, on the basis of Operation 1, the dynamic time slots in the idle state are used as shared contention time slots.

[0088] In this embodiment, two operations for dividing the shared contention time slot are provided. Operation 1 is that in addition to allocating the required number of sub - time slots for all indoor units, for example, allocating one sub - time slot to each indoor unit or multiple sub - time slots to a certain indoor unit, on the basis of the required number of sub - time slots for all indoor units, at least one additional sub - time slot is added as a shared contention time slot, and the added shared contention time slots are by default arranged with the last numbers, without affecting the sending of other indoor units. As Figure 4 shown in the first frame of, time slot 3 is the added shared contention time slot, and indoor unit A, indoor unit B, and indoor unit C can all pre - empt time slot 3.

[0089] Further, Operation 2 is set based on Operation 1. As mentioned above, not all indoor units will go online and run. For those indoor units that do not go online and run, their sub-slots are in an idle state. We mark them as dynamic slots. If these dynamic slots are not used, they will still complete their time periods. Therefore, we can utilize these dynamic slots and use them as shared contention slots to increase the number of shared contention slots to meet multiple indoor units that need to send additional requests or additional data. For example Figure 4 In the second frame of Figure 4 , Slot 1 of indoor unit B is in an idle state and is used as a shared contention slot. Both indoor unit A and indoor unit C can preempt Slot 1. If all indoor units go online and run, it means that there are no dynamic slots in the current frame. Then, at this time, the indoor units can only send additional requests and additional data through the shared contention slots divided by Operation 1.

[0090] Preferably, among them, the additional data is emergency warning data or fault data;

[0091] After receiving the additional request or additional data in the current frame, the outdoor unit reallocates the sub-slots of all indoor units according to the additional request or additional data, generates a new time slot allocation table for the communication cycle of the subsequent frame, and sends the new time slot allocation table to all indoor units through the downlink time slot of the current frame. All indoor units perform data sending operations according to the new time slot allocation table in the communication cycle of the subsequent frame.

[0092] In this embodiment, when the outdoor unit receives an additional request, it will allocate more sub-slots to the indoor unit that sends the additional request in the next frame. Similarly, when the outdoor unit receives additional data, it is default that the indoor unit that sends the additional data needs to send fault data in addition to the daily data (such as temperature and other operating status data). Therefore, it will also allocate more sub-slots to the indoor unit that sends the additional data. When the length of the frame cannot be adjusted, more sub-slots can be formed by shortening the length of all sub-slots to be allocated to the indoor units in need.

[0093] Preferably, when all indoor units go online and run, each indoor unit sends data to the outdoor unit according to the corresponding static time slot;

[0094] When there are indoor units that do not go online and run, if the current indoor unit itself needs to send this data, and this data does not include additional data or additional requests, then it is judged whether there are N dynamic slots before the static time slot corresponding to the current indoor unit and there are no other static time slots, N > a, where a represents the number of sub-slots reserved for other indoor units to preempt. If so, the nth dynamic time slot is allocated to the current indoor unit to send data, a + 1 ≤ n ≤ N, and at the same time, the static time slot corresponding to the current indoor unit is reserved. If not, the current indoor unit sends data according to the corresponding static time slot;

[0095] Or determine whether there are N dynamic time slots between the static time slot corresponding to the current indoor unit and another static time slot in front of it, where N > a, and a represents the number of sub-time slots reserved for other indoor units to preempt. If so, allocate the nth dynamic time slot between the two static time slots to the current indoor unit for data transmission, where a + 1 ≤ n ≤ N. At the same time, retain the static time slot corresponding to the current indoor unit. If not, the current indoor unit sends data according to the corresponding static time slot.

[0096] In this embodiment, when there is an indoor unit that is not online and running, it means that some sub-time slots are in an idle state. We need to use these dynamic time slots to avoid wasting time period resources. Therefore, for indoor units with data transmission requirements, scheduling can be performed by judging the dynamic time slots. For example, Figure 5 As shown, there are 8 indoor units in the air conditioner group control system, namely A, B, C, D, E, F, G, and H, which respectively correspond to the sub-time slots numbered 0 - 7. When a = 1, where a represents the number of sub-time slots reserved for other indoor units to preempt, if only indoor units C, D, and H are online and running:

[0097] Example 1: The 2nd sub-time slot corresponding to indoor unit C is a static time slot. There are 2 dynamic time slots, namely 0 and 1, in front of it, and there is no other static time slot in front of the 2nd static time slot. At this time, N = 2 and N > a. Then indoor unit C can use the nth dynamic time slot, that is, a + 1 = 2 ≤ n ≤ N = 2. So n = 2, which means indoor unit C can use the 2nd dynamic time slot, that is, the 1st dynamic time slot.

[0098] Example 2: The 7th sub-time slot corresponding to indoor unit H is a static time slot. In front of it is the 3rd static time slot of indoor unit D. Then there are 3 dynamic time slots, namely 4, 5, and 6, between indoor unit H and indoor unit D. That is, N = 3 and N > a. Then indoor unit H can use the nth static time slot, that is, a + 1 = 2 ≤ n ≤ N = 3. So n = 2 or 3. Therefore, indoor unit H can use the 2nd or 3rd dynamic time slot among the 3 dynamic time slots 4, 5, and 6, that is, the 5th and 6th dynamic time slots.

[0099] Example 3: The 3rd sub-time slot corresponding to indoor unit D is a static time slot. In front of it is the 2nd static time slot of indoor unit C, and there are no other dynamic time slots between them. Then indoor unit D can only send data using its own corresponding 3rd static time slot and cannot be scheduled to other dynamic time slots.

[0100] It should be noted that a represents the number of sub - time slots reserved for other indoor units to preempt. For example, in Example 1, a = 1, which means the number of sub - time slots reserved for other indoor units to preempt is 1. That is, there are two dynamic time slots, slot 0 and slot 1, in front of indoor unit C. However, slot 0 is used as a shared competition time slot for other indoor units to preempt. Therefore, indoor unit C can only be scheduled to slot 1. In Example 2, there are three dynamic time slots, slot 4, slot 5, and slot 6, between indoor unit H and indoor unit D. When a = 1, it means that slot 4 is used as a shared competition time slot for other indoor units to preempt. Therefore, indoor unit H can only be scheduled to slot 5 and slot 6. Since the priority of preempting the shared competition time slot is higher than the priority of scheduling and using other dynamic time slots, N must be greater than a, leaving a dynamic time slots as shared competition time slots for other indoor units to preempt. The size of a is set according to the actual situation.

[0101] Preferably, when the nth dynamic time slot allocated to the current indoor unit for sending data is preempted by other indoor units as a shared competition time slot to send additional requests or additional data, the (n + 1)th dynamic time slot is allocated to the current indoor unit. If the (n + 1)th dynamic time slot is also preempted by other indoor units as a shared competition time slot to send additional requests or additional data, the (n + 2)th dynamic time slot is allocated to the current indoor unit, and so on... until there are no dynamic time slots available for the current indoor unit to send this data, the current indoor unit sends data according to the corresponding static time slot.

[0102] In this embodiment, since the priority of using the dynamic time slot as a shared competition time slot preempted by other indoor units is higher than the priority of the indoor unit scheduling and using other dynamic time slots to send data, the scheduling and use must follow the avoidance principle. For example, in Example 2 above, there are three dynamic time slots, slot 4, slot 5, and slot 6, between indoor unit H and indoor unit D. Slot 4 is reserved as a shared competition time slot from the beginning. Indoor unit H can only be scheduled to the second dynamic time slot, i.e., slot 5, or the third dynamic time slot, i.e., slot 6. At this time, the indoor unit preferentially uses the second dynamic time slot, i.e., slot 5. If slot 5 is still preempted by other indoor units as a shared competition time slot at this time, indoor unit H needs to give way to the third dynamic time slot, i.e., slot 6. If slot 6 is also preempted by other indoor units as a shared competition time slot at this time, then there are no other dynamic time slots available for indoor unit H to schedule, and indoor unit H can only use its corresponding static time slot 7.

[0103] Further, when the indoor unit C and the indoor unit H can use other dynamic time slots for scheduling and sending data in advance, the static time slots corresponding to the indoor unit C and the indoor unit H themselves still have to be reserved for their own use. One reason is that even though there are dynamic time slots available for scheduling, the dynamic time slots may be preempted at any time as shared contention time slots. Therefore, it is necessary to reserve the static time slots corresponding to themselves to prevent the situation where, after scheduling, they are preempted but there are no sub-time slots available for sending messages. For the indoor unit with successful scheduling, for the static time slot corresponding to itself, we allow the indoor unit with successful scheduling to repeatedly send the same data or send other real-time data.

[0104] Preferably, all sub-time slots divided from the uplink time slot are embedded with guard time, and the interval lengths of the guard time corresponding to each sub-time slot are the same;

[0105] The calculation formula for the guard time is:

[0106] T = T mpd + T ce + T pre ;

[0107] where T represents the guard time, T mpd represents the maximum propagation delay, T ce represents the clock error, T pre represents the pre-allocated time, and the total length of the pre-allocated time for all indoor units is the length of one sub-time slot.

[0108] Preferably, when the outdoor unit receives data sent from all indoor units and receives additional data or additional requests sent from different indoor units within consecutive communication cycles of multiple frames, the outdoor unit shortens the guard time of each sub-time slot, merges the pre-allocated time in the original guard time to be used for dividing one more new sub-time slot, uses the new sub-time slot as a shared contention time slot, and the outdoor unit re-formulates a new time slot allocation table and broadcasts it to all indoor units through the downlink time slot;

[0109] The calculation formula for the shortened guard time is:

[0110] T = T mpd + T ce 。

[0111] In this embodiment, the guard time is used as the buffer time between time slots, and the purpose is to prevent signal overlap caused by clock drift or transmission delay. Therefore, each sub-time slot needs to be embedded with guard time. In the existing TDMA technology, the guard time is generally the sum of the maximum propagation delay and the clock error. In the present invention, the pre-allocated time is added, and the total length of the pre-allocated time for all sub-time slots constitutes the length of one sub-time slot, so that the pre-allocated time can be removed later to add a new sub-time slot as a shared contention time slot, solving the problem of insufficient shared contention time slots;

[0112] After adding new sub - time slots, all atomic time slots can still maintain their original actual available lengths while retaining the basic protection time. For example, during the off - peak season of air - conditioner use, each of the 5 indoor units is allocated a sub - time slot of 12 ms. The 12 - ms sub - time slot includes a protection time of 4 ms. The actual available time for each sub - time slot is 8 ms. In the 4 - ms protection time, the maximum propagation delay is 1.5 ms, the clock error is 0.5 ms, and the pre - allocated time is 2 ms. That is, in an atomic time slot, the actual available length of 8 ms plus the protection time of 4 ms (maximum propagation delay of 1.5 ms, clock error of 0.5 ms, pre - allocated time of 2 ms) equals 12 ms. There are 5 indoor units in the uplink time slot, so the total length of the uplink time slot is 5×12 ms = 60 ms. Now, if we remove the 2 - ms pre - allocated time and retain the basic protection time, and add a new sub - time slot, that is, there are a total of 6 sub - time slots. Then, in these 6 sub - time slots, the length of each is the actual available length of 8 ms plus the protection time of 2 ms (maximum propagation delay of 1.5 ms, clock error of 0.5 ms), which equals 10 ms. The total length of the uplink time slot is 6×10 ms = 60 ms. That is, the total length of the uplink time slot remains unchanged, and there is no need to change the frame period length. After adding new sub - time slots, the actual available length of each sub - time slot remains unchanged, and the basic protection time is retained to prevent signal overlap caused by clock drift or transmission delay.

[0113] Preferably, as Figure 3 shown, the outdoor unit sending data to the indoor unit through the downlink time slot further includes:

[0114] Dividing the downlink time slot into sub - time slots with the same number as the indoor units, and allocating each sub - time slot to the corresponding indoor unit, so that the outdoor unit sends specified data for different indoor units in different sub - time slots.

[0115] In this embodiment, in addition to being able to send data to all indoor units or specific indoor units in the form of broadcast or unicast by monopolizing the downlink time slot, the outdoor unit can also divide the downlink time slot according to the division method of the uplink time slot into sub - time slots with the same number as the indoor units, so that the outdoor unit sends instructions for different indoor units in different sub - time slots. For example, if the outdoor unit needs to control indoor unit A (set temperature), indoor unit B (adjust wind speed), and indoor unit C (switch mode) simultaneously, the downlink time slot can be divided into 3 sub - time slots to send the corresponding instructions respectively, thereby improving the instruction transmission efficiency and avoiding redundant broadcast data.

[0116] Preferably, when the outdoor unit sends data to the indoor unit through the downlink time slot in the current frame, it will attach a start identifier at the frame starting point, and all indoor units use the start identifier as a synchronization signal to align the clocks.

[0117] In this embodiment, it is necessary to ensure that the clocks of all indoor units and outdoor units are aligned so that the sub-time slots can be accurately switched and scheduled. Therefore, within the communication cycle of each frame, the outdoor unit will send a start identifier to the indoor unit through the downlink time slot, enabling all indoor units to align their clocks with the start identifier as the synchronization signal.

[0118] The technical principle of the present invention has been described above in conjunction with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be construed in any way as a limitation on the protection scope of the present invention. Based on the explanations herein, those skilled in the art can readily conceive of other specific embodiments of the present invention without creative efforts, and these embodiments will fall within the protection scope of the present invention.

Claims

1. A method for dynamically allocating communication time periods between an indoor unit and an outdoor unit of an air conditioner, which includes using the same wireless frequency band for the outdoor unit and multiple indoor units in an air conditioner group control system to share the same communication channel, dividing the communication time of the communication channel into multiple time frames of fixed length, dividing each time frame into an uplink time slot and a downlink time slot, dividing the uplink time slot into multiple sub - time slots of fixed length, where the uplink time slot is used for multiple indoor units to send data to the outdoor unit, and the downlink time slot is used for the outdoor unit to send data to multiple indoor units, and is characterized in that: Step A: When dividing the uplink time slot into sub - time slots, the number of the sub - time slots is greater than or equal to the number of indoor units; Step B: Initially, the outdoor unit sequentially numbers each sub - time slot, assigns the sub - time slot with the corresponding number to each indoor unit according to the SN code of each indoor unit and generates a time slot allocation table, and the outdoor unit broadcasts the time slot allocation table to all indoor units through the downlink time slot; Step C: During the communication cycle of the current frame, each indoor unit sends data to the outdoor unit in sequence according to the corresponding numbered sub - time slot, and the outdoor unit sends data to all indoor units in a broadcast form according to all indoor unit addresses or sends data to the corresponding indoor unit in a unicast form according to the target indoor unit address through the downlink time slot; Step D: During other communication cycles of subsequent frames, the outdoor unit re - allocates the sub - time slots of all indoor units according to the communication data volume or communication priority of all indoor units, generates a new time slot allocation table and broadcasts it to all indoor units, and all indoor units perform data sending operations according to the new time slot allocation table; Step E: When a new indoor unit is connected to the air conditioner group control system, steps A to D are re - executed.

2. The method for dynamically allocating communication time periods between an indoor unit and an outdoor unit of an air conditioner according to claim 1, characterized in that: Obtain the online operation status of all indoor units to determine the communication status of all sub - time slots in the current frame, mark the sub - time slots corresponding to the online - running indoor units as static time slots in a busy state, and mark the sub - time slots corresponding to the non - online - running indoor units as dynamic time slots in an idle state.

3. The method for dynamically allocating communication time periods between an indoor unit and an outdoor unit of an air conditioner according to claim 2, characterized in that: Divide at least one sub - time slot in the uplink time slot as a shared contention time slot, and the shared contention time slot is used for an indoor unit to initiate an additional request for the communication requirement of the next frame to the outdoor unit in the current frame by preempting the shared contention time slot or for the indoor unit to send additional data again; Dividing at least one shared contention time slot includes: Operation 1: In addition to dividing the number of sub - time slots required by the indoor units in the uplink time slot, at least one sub - time slot needs to be divided as a shared contention time slot, and the number of the shared contention time slot is arranged at the end; Or Operation 2: If there are dynamic time slots in an idle state in the current frame, on the basis of Operation 1, the dynamic time slots in an idle state are used as shared contention time slots.

4. The method for dynamically allocating communication time periods between an indoor unit and an outdoor unit of an air conditioner according to claim 3, characterized in that: Among them, The additional data is emergency warning data or fault data; After the outdoor unit receives an additional request or additional data in the current frame, it reallocates the sub-slots of all indoor units according to the additional request or additional data, generates a new time slot allocation table for the communication cycle of subsequent frames, and sends the new time slot allocation table to all indoor units through the downlink time slot of the current frame. All indoor units perform data transmission operations according to the new time slot allocation table in the communication cycle of subsequent frames.

5. The method for dynamically allocating communication time periods between an air conditioner indoor unit and an outdoor unit according to claim 4, characterized in that: When all indoor units are online and running, each indoor unit sends data to the outdoor unit according to the corresponding static time slot. When there are indoor units that are not online and running, if the current indoor unit itself needs to send this data, and this data does not include additional data or additional requests, then it is judged whether there are N dynamic time slots in front of the static time slot corresponding to the current indoor unit when there are no other static time slots in front of the static time slot corresponding to the current indoor unit. N > a, where a represents the number of sub-slots reserved for other indoor units to preempt and occupy. If so, the nth dynamic time slot is allocated to the current indoor unit for data transmission, where a + 1 ≤ n ≤ N, and at the same time, the static time slot corresponding to the current indoor unit is reserved. If not, the current indoor unit sends data according to the corresponding static time slot. Or it is judged whether there are N dynamic time slots between the static time slot corresponding to the current indoor unit and another static time slot in front of it. N > a, where a represents the number of sub-slots reserved for other indoor units to preempt and occupy. If so, the nth dynamic time slot between the two static time slots is allocated to the current indoor unit for data transmission, where a + 1 ≤ n ≤ N, and at the same time, the static time slot corresponding to the current indoor unit is reserved. If not, the current indoor unit sends data according to the corresponding static time slot.

6. The method for dynamically allocating communication time periods between an air conditioner indoor unit and an outdoor unit according to claim 5, characterized in that: When the nth dynamic time slot allocated to the current indoor unit for data transmission is preempted by other indoor units as a shared competition time slot to send additional requests or additional data, the (n + 1)th dynamic time slot is allocated to the current indoor unit. If the (n + 1)th dynamic time slot is also preempted by other indoor units as a shared competition time slot to send additional requests or additional data, the (n + 2)th dynamic time slot is allocated to the current indoor unit, and so on... until there are no dynamic time slots available for the current indoor unit to send this data, the current indoor unit sends data according to the corresponding static time slot.

7. The method for dynamically allocating communication time periods between an air conditioner indoor unit and an outdoor unit according to claim 4, characterized in that: All sub-slots divided by the uplink time slot are embedded with guard times, and the interval lengths of the guard times corresponding to each sub-slot are the same. The calculation formula for the guard time is: T = T mpd + T ce + T pre ; Among them, T represents the protection time, T mpd represents the maximum propagation delay, T ce represents the clock error, T pre represents the pre-allocated time, and the total length of the pre-allocated time of all internal machines is the length of one sub-slot.

8. The method for dynamically allocating communication time periods between an air conditioner indoor unit and an outdoor unit according to claim 7, characterized in that: When, in the communication cycles of consecutive multiple frames, the outdoor unit receives data sent by all indoor units and receives additional data or additional requests sent by different indoor units, the outdoor unit shortens the guard time of each sub-slot, combines the pre-allocated time in the original guard time to be used for dividing one more new sub-slot, uses the new sub-slot as a shared competition time slot, and the outdoor unit re-formulates a new time slot allocation table and broadcasts it to all indoor units through the downlink time slot. The calculation formula for the shortened protection time is as follows: T = T mpd + T ce 。 9. A method for dynamically allocating communication time slots between an indoor unit and an outdoor unit of an air conditioner according to claim 1, characterized in that: When the outdoor unit sends data to the indoor unit through a downlink time slot, it further includes: Dividing the downlink time slot into sub-time slots with the same number as the indoor units, and allocating each sub-time slot to a corresponding indoor unit, so that the outdoor unit sends specified data for different indoor units in different sub-time slots.

10. A method for dynamically allocating communication time slots between an indoor unit and an outdoor unit of an air conditioner according to claim 1, characterized in that: When the outdoor unit sends data to the indoor unit through a downlink time slot in the current frame, a start identifier is attached at the frame start point, and all indoor units align their clocks with the start identifier as the synchronization signal.

Images