Multi-connected air conditioning system and control method thereof

Abstract

The application provides a multi-connected air conditioner system and a control method thereof, the system comprising an air conditioner network data link layer, an air conditioner network data transmission layer and an air conditioner network data application layer, a transceiver of an outdoor master machine communicating with a transceiver of each outdoor slave machine and a transceiver of each indoor slave machine through a CAN bus, the transceiver of the outdoor master machine, the transceiver of the outdoor slave machine and the transceiver of the indoor slave machine all communicating with respective corresponding function modules, a control module of the outdoor master machine communicating with a corresponding management module thereof, and a control module of each outdoor slave machine and a control module of each indoor slave machine both communicating with respective corresponding function modules. The application can meet the needs of application scenarios with a large number of nodes and intelligent management of air conditioner big data.

Description

Technical Field

[0001] This invention relates to the field of multi-split air conditioning technology, and in particular to a multi-split air conditioning system and its control method. Background Technology

[0002] Multi-split air conditioning systems allow multiple outdoor units to control multiple indoor units in parallel. Since there are multiple indoor units, the demand for operating each unit varies. The outdoor units adjust the compressor frequency based on the demand from the indoor units to achieve the desired indoor cooling effect.

[0003] The communication mechanisms of multi-split air conditioning systems on the market vary greatly. Poor communication mechanisms and control methods can affect the working efficiency of air conditioning systems and cannot meet the needs of application scenarios with a large number of nodes or the needs of intelligent management of air conditioning big data. Summary of the Invention

[0004] This invention provides a multi-split air conditioning system and its control method to address the limitations of existing technologies in meeting the needs of application scenarios with a large number of nodes and the requirements for intelligent management of air conditioning big data.

[0005] In a first aspect, the present invention provides a multi-split air conditioning system, the system comprising:

[0006] The air conditioning network data link layer is configured with a corresponding transceiver for each air conditioning node. Multiple air conditioning nodes include an outdoor host, multiple outdoor slaves, and multiple indoor slaves. The transceiver of the outdoor host communicates with the transceivers of each outdoor slave and each indoor slave via a CAN bus.

[0007] The air conditioning network data transmission layer is equipped with a management module and a function module for the outdoor unit, and a function module is also equipped for each outdoor slave unit and each indoor slave unit. The transceiver of the outdoor unit, the transceiver of the outdoor slave unit, and the transceiver of the indoor slave unit all communicate with their respective function modules.

[0008] The air conditioning network data application layer is equipped with a control module for monitoring the operating status of the outdoor unit, each outdoor slave unit, and each indoor slave unit. The control module of the outdoor unit communicates with its corresponding management module, and the control modules of each outdoor slave unit and each indoor slave unit communicate with their respective functional modules.

[0009] In one embodiment of the present invention, each air conditioning node is equipped with an MCU, a transceiver chip circuit and a CAN adaptive control circuit at the air conditioning network data link layer. The chip circuit includes a first transceiver chip and a second transceiver chip. The MCU outputs an enable signal to control the CAN adaptive control circuit to selectively turn on either the first transceiver chip or the second transceiver chip to achieve polarity switching of the CAN bus.

[0010] In one embodiment of the present invention, the MCU is configured with a data stream receiving interface, a data stream sending interface, a data protocol packet converter, a data receiving filter, a receiving register, a main sending register, a secondary sending register, a clock prescaler, and a transceiver controller.

[0011] The data stream receiving interface receives data packets from the CAN bus, and the data packet converter unpacks the data packets and inputs them to the data receiving filter to filter the CAN ID. After filtering the CAN ID data, the data is stored in the receiving register. The transceiver controller uses the peripheral high-speed bus or receives an interrupt command to allow the air conditioning network data transmission layer to retrieve the data from the receiving register and perform data processing.

[0012] The air conditioning network data transmission layer sends a data transmission command to the transceiver controller to start data transmission. The transceiver controller controls the main transmission register or the secondary transmission register to be ready. The air conditioning network data transmission layer writes the data to be transmitted into the main transmission register or the secondary transmission register through the peripheral high-speed bus.

[0013] After the data protocol packet converter acquires control of the CAN bus, it sends the data buffered in the main transmit register or the secondary transmit register through the data stream transmission interface. When the transceiver controller detects that the data transmission is complete, it notifies the air conditioning network data transmission layer of the data transmission completion information through an interrupt command.

[0014] In one embodiment of the present invention, the management module of the outdoor host is used to manage all outdoor slave units and indoor slave units. The management includes the application and allocation of IP addresses for each air conditioning node, communication initiation and timing control. The outdoor host initiates communication on the CAN bus at regular intervals through the management module.

[0015] In one embodiment of the present invention, the functional modules of the outdoor host, each outdoor slave unit and each indoor slave unit are configured with a digital filter, a data transceiver queue module and a data transmission control interface connected in sequence. The digital filter is connected to its corresponding transceiver, and the data transmission control interface is connected to its corresponding control module or management module.

[0016] The outdoor unit's digital filter is used for filtering device IDs or project numbers, filtering CAN IDs, data packet verification, and CAN adaptive control.

[0017] The data transceiver queue module of the outdoor host is used for sending queues, receiving queues, queue overflow management, and queue sending and receiving timing management.

[0018] The data transmission control interface of the outdoor unit includes the engineering code or IP address management interface of the indoor slave unit, which includes the air conditioner node operation status interface, the air conditioner node operation control interface, the protocol converter data transceiver interface, the centralized controller or PC data transceiver interface, and the air conditioner node OTA data transceiver interface.

[0019] In one embodiment of the present invention, the air conditioning network data application layer includes an application layer for each air conditioning device, a central controller device application layer, a protocol converter device application layer, a DTU device application layer, a WIFI central controller device application layer, and an OTA function application layer.

[0020] In one embodiment of the present invention, each transceiver is further configured with a CAN bus access port, a bus protection circuit, an end resistor, and an isolation chip circuit. Each transceiver is connected to the CAN bus through its respective CAN bus access port. The CAN bus access port is connected to the bus protection circuit. The bus protection circuit is connected to the first transceiver chip and the second transceiver chip respectively. The MCU is connected to the first transceiver chip and the second transceiver chip respectively through the isolation chip circuit.

[0021] In one embodiment of the present invention, the CAN bus access port includes a first port, a second port, a third port, and a terminal resistor. The first ends of the first port, the second port, and the third port are all connected to the bus protection circuit. The second ends of the first port and the second port are both connected to the CAN bus. The second end of the third port is connected to the terminal resistor.

[0022] In one embodiment of the present invention, the CAN adaptive control circuit includes a first resistor R56, a second resistor R57, a third resistor R61, a first transistor Q2, a second transistor Q5, and a third transistor Q6. The enable terminal of the isolation chip circuit is connected to the first terminal of the first resistor R56 and the second terminal of the third transistor Q6. The second terminal of the first resistor R56 is connected to the base of the first transistor Q2 and the first terminal of the second resistor R57. The emitter of the first transistor Q2 and the second terminal of the second resistor R57 are both grounded. The collector of the first transistor Q2 is connected to the first terminal of the third resistor R61 and the second terminal of the second transistor Q5. The third terminal of the second transistor Q5... The third terminal of the first transceiver IC10 is connected to the VCC pin and the NC pin of the second transceiver IC11, respectively. The third terminal of the third transistor Q6 is connected to the VCC pin and the NC pin of the second transceiver IC11, respectively. The TXD pin of the first transceiver IC10 is connected to the TXD pin of the second transceiver IC11, the RXD pin of the first transceiver IC10 is connected to the RXD pin of the second transceiver IC11, the CANH pin of the first transceiver IC10 is connected to the CANL pin of the second transceiver IC11 and the bus protection circuit, respectively. The CANL pin of the first transceiver IC10 is connected to the CANH pin of the second transceiver IC11 and the bus protection circuit, respectively.

[0023] In one embodiment of the present invention, the isolation chip circuit includes an isolation chip IC8. The TX-CAN pin of the MCU is connected to the INA pin of the isolation chip IC8 through a fifth resistor R52. The RX-CAN pin of the MCU is connected to the OUTC pin of the isolation chip IC8 through a sixth resistor R54. The OUTA pin of the isolation chip IC8 is connected to the TXD pin of the first transceiver chip IC10 and the TXD pin of the second transceiver chip IC11, respectively. The INC pin of the isolation chip IC8 is connected to the RXD pin of the first transceiver chip IC10 and the RXD pin of the second transceiver chip IC11, respectively. The OUTB pin of the isolation chip IC8 is connected to the enable terminal CS of the CAN adaptive control circuit to output an enable signal to the CAN adaptive control circuit.

[0024] In a second aspect, the present invention also provides a control method for a multi-split air conditioning system, the control method being applied to the multi-split air conditioning system as described in the first aspect, the control method comprising:

[0025] Based on the preset values ​​of prescaler, CAN clock frequency and baud rate set in the MCU register, the value ranges of the first target phase buffer segment, the second target phase buffer segment and the target resynchronization compensation width are obtained.

[0026] The register is controlled to send data based on the value range, and the sending status information of the register is read to obtain the success rate;

[0027] The values ​​of the first target phase buffer segment, the second target phase buffer segment, and the target resynchronization compensation width are adjusted according to the success rate to obtain the optimal baud rate setting.

[0028] In one embodiment of the present invention, the step of obtaining the value ranges of the first target phase buffer segment, the second target phase buffer segment, and the target resynchronization compensation width based on the preset values ​​of prescaler, CAN clock frequency, and baud rate set in the MCU register includes:

[0029] The time quantum is obtained based on the prescaler and CAN clock frequency set in the MCU registers;

[0030] Based on the preset values ​​of time quantum and baud rate, and according to the baud rate calculation formula, the first value range of the first target phase buffer segment, the second target phase buffer segment, and the target resynchronization compensation width is obtained;

[0031] The formula for calculating this time quantum is:

[0032] TQ = (PRESC + 1) / fcan_clk, where TQ represents the time quantum, PRESC represents the prescaler set in the MCU register, and fcan_clk represents the CAN clock frequency;

[0033] The baud rate calculation formula is as follows:

[0034] BT = TSEG1 + TSEG2 = ((SEG_1 + 2) + (SEG_2 + 1)) × TQ, where BT represents the baud rate, SEG1 represents the first target phase buffer segment, SEG2 represents the second target phase buffer segment, SEG_1 represents the first reference phase buffer segment, SEG_2 represents the second reference phase buffer segment, and T represents time.

[0035] In one embodiment of the present invention, the step of obtaining a first range of values ​​for the first target phase buffer segment, the second target phase buffer segment, and the target resynchronization compensation width based on the preset values ​​of the time quantum and baud rate, and according to the baud rate calculation formula, includes:

[0036] The first reference phase buffer segment and the second reference phase buffer segment are set through the first reference phase buffer segment bit and the second reference phase buffer segment bit in the register, and the corresponding reference value range is:

[0037] 0≤SEG_1≤63, 0≤SEG_2≤7, 0≤SJW_1≤7, and

[0038] SEG_2+1≤SEG_1,SJW_1≤SEG_2,SJW_1 represents the reference resynchronization compensation width;

[0039] Based on the baud rate calculation formula, and according to the time quantum, the preset baud rate value, and the reference value range, the first target phase buffer segment, the second target phase buffer segment, and the first value range of the target resynchronization compensation width are obtained.

[0040] In one embodiment of the present invention, the step of controlling the register to send data based on the value range includes:

[0041] Based on the first value range, the set values ​​of the first target phase buffer segment, the second target phase buffer segment, and the target resynchronization compensation width are written into the register, which includes a transmit register and a receive register.

[0042] Set the transmit register to CAN transmit data mode and the corresponding receive register to CAN receive data mode;

[0043] Monitor the CAN bus for CAN communication data at preset time intervals;

[0044] If no CAN communication data is available, the polarity of the CAN bus is switched and listening continues; if CAN communication data is available, the received CAN communication data is written into the transmit register and the transmit register is controlled to transmit the data.

[0045] In one embodiment of the present invention, the step of reading the transmission status information of the register to obtain the success rate includes:

[0046] Read the transmission status information of the transmission register, calculate the success rate based on the number of data transmitted and the number of data successfully transmitted within the time window, and calculate the error value based on the success rate;

[0047] The formulas for calculating the success rate and error value are as follows:

[0048] Fm = Tount1 / Tcount0 * 100%;

[0049] ΔFm = 100% - Fm;

[0050] Where Fm represents the success rate, Tount1 represents the number of data successfully sent, Tcount0 represents the number of data sent, and ΔFm represents the error value.

[0051] In one embodiment of the present invention, the step of adjusting the values ​​of the first target phase buffer segment, the second target phase buffer segment, and the target resynchronization compensation width according to the success rate to obtain the optimal baud rate setting includes:

[0052] Based on the error value and the preset baud rate value, and according to the baud rate calculation formula, the first target phase buffer segment and the second target phase buffer segment are increased, and the time quantum is decreased to perform fuzzy adjustment;

[0053] Based on the result of the fuzzy adjustment, it is determined whether the error value has decreased;

[0054] If the error value increases, the first target phase buffer segment and the second target phase buffer segment are lowered and the time quantum is increased according to the baud rate calculation formula to perform fuzzy adjustment.

[0055] Based on the fuzzy adjustment method that can reduce the error value, proportional-integral-derivative adjustment is performed while keeping the time quantum constant, so as to obtain the adjusted values ​​of the second target phase buffer segment and the target resynchronization compensation width;

[0056] Based on the adjustment value, a second range of values ​​for the second target phase buffer segment and the target resynchronization compensation width is determined.

[0057] In one embodiment of the present invention, the step of adjusting the values ​​of the first target phase buffer segment, the second target phase buffer segment, and the target resynchronization compensation width according to the success rate to obtain the optimal baud rate setting value further includes:

[0058] Based on the second value range, assign values ​​to the second target phase buffer segment and the target resynchronization compensation width;

[0059] Based on the assigned value, determine whether the error value has decreased and whether it is within the adjustment period of the optimal baud rate setting;

[0060] If the error value decreases and is within the adjustment period of the optimal baud rate setting, then when the error value is lower than or equal to the first preset threshold, the first target phase buffer segment, the second target phase buffer segment, the target resynchronization compensation width, and the time quantum are determined to be the target assignment.

[0061] The optimal baud rate setting value is obtained according to the target value and the baud rate calculation formula.

[0062] In one embodiment of the present invention, after the step of determining the optimal baud rate setting value according to the baud rate calculation formula based on the target assignment, the control method further includes:

[0063] Determine whether the adjustment period for determining the optimal baud rate setting exceeds the second preset threshold;

[0064] If it is determined that the adjustment period of the most baud rate setting exceeds the second preset threshold, then return to the step of assigning values ​​to the second target phase buffer segment and the target resynchronization compensation width based on the second value range.

[0065] This invention provides a multi-split air conditioning system and its control method. By setting up a network hierarchical topology structure of air conditioning network data link layer, air conditioning network data transmission layer and air conditioning network data application layer, it can meet the needs of application scenarios with a large number of nodes and intelligent management of air conditioning big data, improve the installation efficiency of multi-split air conditioning, expand the total number of access nodes, and has high data transmission efficiency. The network layer structure is clear and supports the rapid intelligent iteration of multi-split air conditioning. Attached Figure Description

[0066] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0067] Figure 1 This is a schematic diagram of the structure of the multi-split air conditioning system provided by the present invention;

[0068] Figure 2 This is a schematic diagram of the structure of the multi-split air conditioning system provided in an embodiment of the present invention.

[0069] Figure 3 This is a circuit diagram of multiple transceivers in the data link layer provided in an embodiment of the present invention;

[0070] Figure 4 yes Figure 3 The circuit diagram of the transceiver shown in the dashed line section;

[0071] Figure 5 This is a schematic diagram of the MCU circuit for the data link layer provided in an embodiment of the present invention;

[0072] Figure 6 This is a schematic diagram of the data transmission layer module provided in an embodiment of the present invention;

[0073] Figure 7 This is a flowchart illustrating the control method for a multi-split air conditioning system provided by the present invention;

[0074] Figure 8 This is a CAN bit timing diagram for CAN baud rate setting provided in an embodiment of the present invention. Detailed Implementation

[0075] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0076] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein.

[0077] The technical terms involved in this invention are described below:

[0078] CAN bus is short for Controller Area Network, a serial communication bus standard that enables distributed real-time control.

[0079] To address the limitations of existing technologies in meeting the needs of applications with a large number of nodes and the requirements for intelligent management of air conditioning big data, this invention provides a multi-split air conditioning system and its control method. By setting up a network hierarchical topology structure consisting of an air conditioning network data link layer, an air conditioning network data transmission layer, and an air conditioning network data application layer, this system can meet the needs of applications with a large number of nodes and the requirements for intelligent management and control of air conditioning big data. It improves the installation efficiency of multi-split air conditioning, expands the total number of access nodes, and has high data transmission efficiency. The network layer structure is clear and supports rapid intelligent iteration of multi-split air conditioning systems.

[0080] The following is combined with Figures 1-8 This invention describes a multi-split air conditioning system and its control method.

[0081] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of the multi-split air conditioning system provided by the present invention. The multi-split air conditioning system includes an air conditioning network data link layer, an air conditioning network data transmission layer, and an air conditioning network data application layer.

[0082] For example, the air conditioning network data link layer is configured with a corresponding transceiver for each air conditioning node. The multiple air conditioning nodes include an outdoor host, multiple outdoor slaves and multiple indoor slaves. The transceiver of the outdoor host communicates with the transceivers of each outdoor slave and each indoor slave via a CAN bus.

[0083] It should be noted that one outdoor unit can be designated as the outdoor master unit, and the other outdoor units can be designated as outdoor slave units.

[0084] For example, the air conditioning network data transmission layer is configured with a management module and a function module for the outdoor host, and a function module is configured for each outdoor slave unit and each indoor slave unit. The transceiver of the outdoor host, the transceiver of the outdoor slave unit, and the transceiver of the indoor slave unit all communicate with their respective function modules.

[0085] For example, the air conditioning network data application layer is equipped with a control module for monitoring the operating status of the outdoor host, each outdoor slave unit and each indoor slave unit. The control module of the outdoor host communicates with its corresponding management module, and the control module of each outdoor slave unit and the control module of each indoor slave unit communicate with their respective functional modules.

[0086] Therefore, the multi-split air conditioning system of the present invention adopts a clear network layer structure (such as air conditioning network data link layer, air conditioning network data transmission layer and air conditioning network data application layer), which can meet the application scenarios with a large number of nodes (for example, the number of indoor air conditioning units reaches 80 or more) and meet the needs of intelligent management and control of air conditioning big data, improve the installation efficiency of multi-split air conditioning, expand the total number of access nodes, and has high data transmission efficiency and supports the rapid intelligent iteration of multi-split air conditioning.

[0087] The above-mentioned multi-split air conditioning system is described below through an embodiment.

[0088] Please refer to Figure 2 , Figure 2 This is a schematic diagram of the structure of a multi-split air conditioning system provided in an embodiment of the present invention. The multi-split air conditioning system includes multiple outdoor units and multiple indoor units. One outdoor unit is selected as the outdoor master unit, and the other outdoor units act as outdoor slave units. The multiple indoor units act as indoor slave units. The network layer structure of the multi-split air conditioning system, configured sequentially from the underlying hardware to the upper-level software, is as follows: air conditioning network data link layer, air conditioning network data transmission layer, and air conditioning network data application layer. The transceiver of the outdoor master unit is connected to the terminal resistors of the other transceivers via a CAN bus.

[0089] For example, in the data link layer of an air conditioning network, Figure 3 This is a circuit diagram of multiple transceivers at the data link layer provided in an embodiment of the present invention. Figure 4 yes Figure 3 The section marked with dashed lines represents the transceiver circuit diagram, specifically the CAN Bus Circuit. From... Figure 2 It can be seen that an air conditioning node (such as an outdoor unit, an outdoor slave unit, or an indoor slave unit) includes an MCU chip, a CAN controller, and a CAN transceiver. However, from... Figure 3 , Figure 4 As can be seen, the air conditioning node shown in this invention uses an MCU chip with an integrated CAN controller and a CAN transceiver.

[0090] For example, such as Figure 4 As shown, each air conditioning node is equipped with an MCU (such as Indoor-MCU CAN slave for indoor slave, Outdoor-MCU CAN master for outdoor master, and Outdoor-MCU CAN slave for outdoor slave), isolation chip circuit, transceiver chip circuit, CAN adaptive control circuit, bus protection circuit, CAN bus access port, and end resistor at the air conditioning network data link layer.

[0091] For example, the CAN bus access interface provides a first connector CN13, a second connector CN14, and a third connector CN15. The first terminals of the first connector CN13, the second connector CN14, and the third connector CN15 are all connected to a bus protection circuit for accessing the CAN bus. The second terminals of the first connector CN13 and the second connector CN14 are both connected to the CAN bus. The second terminal of the third connector CN15 is connected to an end resistor. The connection of the third connector CN15 to the end resistor End-R allows for convenient selection of the air conditioner at the end of the CAN bus, facilitating air conditioning installation.

[0092] For example, such as Figure 3 The first port CN13 of one transceiver is shown to be connected to the first port CN13 or the second port CN14 of another transceiver via a CAN bus.

[0093] For example, the bus protection circuit is connected to the CAN bus access port respectively, and includes diodes DZ1 to DZ3. Through the bus protection circuit, interference such as electrostatic discharge / lightning strikes on the bus can be prevented, ensuring the electrical reliability of the CAN bus.

[0094] For example, the transceiver chip circuit includes a first transceiver chip IC10 and a second transceiver chip IC11. One signal line of the bus protection circuit is connected to the CANL pin of the first transceiver chip IC10 and the CANH pin of the second transceiver chip IC11 via resistor R91. The other signal line of the bus protection circuit is connected to the CANH pin of the first transceiver chip IC10 and the CANL pin of the second transceiver chip IC11 via resistor R92. Since the CAN bus network is connected to CAN_H and CAN_L, and each air conditioning node uses these two lines for serial differential signal transmission, resistors R91 and R92 are connected between CAN_H and CAN_L to avoid signal reflection and interference.

[0095] Therefore, the transceiver chip circuit (i.e., the CAN transceiver, including the first transceiver chip IC10 and the second transceiver chip IC11) is responsible for the conversion between logic level and signal level. That is, it outputs the logic level (TXD) from the MCU to the CAN transceiver, and then converts the logic level into the differential level (CANH / CANL) of the CAN bus through the internal conversion of the CAN transceiver.

[0096] For example, the isolation chip circuit includes an isolation chip IC8. The TX-CAN (for transmitting CAN signals) pin of the MCU is connected to the INA pin of the isolation chip IC8 through a fifth resistor R52. The RX-CAN (for receiving CAN signals) pin of the MCU is connected to the OUTC pin of the isolation chip IC8 through a sixth resistor R54. The OUTA pin of the isolation chip IC8 is connected to the TXD pin of the first transceiver chip IC10 and the TXD pin of the second transceiver chip IC11, respectively. The INC pin of the isolation chip IC8 is connected to the RXD pin of the first transceiver chip IC10 and the RXD pin of the second transceiver chip IC11, respectively. The OUTB pin of the isolation chip IC8 is connected to the enable terminal CS of the CAN adaptive control circuit to output an enable signal to the CAN adaptive control circuit.

[0097] For example, the CAN adaptive control circuit includes a first resistor R56, a second resistor R57, a third resistor R61, a first transistor Q2, a second transistor Q5, and a third transistor Q6. The enable terminal CS of the isolation chip circuit is connected to the first terminal of the first resistor R56 and the second terminal of the third transistor Q6. The second terminal of the first resistor R56 is connected to the base of the first transistor Q2 and the first terminal of the second resistor R57. The emitter of the first transistor Q2 and the second terminal of the second resistor R57 are both grounded. The collector of the first transistor Q2 is connected to the first terminal of the third resistor R61 and the second terminal of the second transistor Q5. The third terminal of the second transistor Q5 is connected to... The VCC and NC pins of the first transceiver chip IC10 are connected. The third terminal of the third transistor Q6 is connected to the VCC and NC pins of the second transceiver chip IC11. The TXD pin of the first transceiver chip IC10 is connected to the TXD pin of the second transceiver chip IC11. The RXD pin of the first transceiver chip IC10 is connected to the RXD pin of the second transceiver chip IC11. The CANH pin of the first transceiver chip IC10 is connected to the CANL pin of the second transceiver chip IC11 and the bus protection circuit. The CANL pin of the first transceiver chip IC10 is connected to the CANH pin of the second transceiver chip IC11 and the bus protection circuit.

[0098] Therefore, by controlling the CAN adaptive control circuit through the MCU output enable signal CS to selectively activate either the first or second transceiver chip, the polarity of the CAN bus is switched. This achieves adaptive CAN access, enabling immediate use upon connection, and also provides foolproof protection for connection. Furthermore, through the isolation chip circuit, reliable transmission of CAN bus data to the MCU chip processor is achieved through filtering and isolation.

[0099] Please continue to refer to this. Figure 5 , Figure 5 This is a schematic diagram of the MCU circuit for the data link layer provided in an embodiment of the present invention. The main function of the MCU is to handle data transmission and reception between the air conditioning network data link layer and the air conditioning network data transmission layer.

[0100] For example, the MCU includes a data stream receive interface CAN_RxD, a data stream transmit interface CAN_TxD, a data protocol packet converter CAN Protocol Machine (Receive Path, Transmit Path), a data receive filter, a receive register Receive Buffer (RB), a primary transmit register Primary Transmit Buffer (PTB), a secondary transmit register Secondary Transmit Buffer (STB), a clock prescaler (for CAN clock input), and a transceiver controller Host Controller Interface CAN (with a peripheral high-speed bus AHB-IF interface / receive interrupt interface).

[0101] For example, the data reception control implementation process is as follows:

[0102] The data stream receiver interface receives data packets from the CAN bus. After the data packet is unpacked (Receive Path) by the data protocol packet converter, the packet is input to the data receive filter to filter the CAN ID. The filtered CAN ID data is then stored in the receive register for later data retrieval. The transceiver controller notifies the air conditioning network data transmission layer via the peripheral high-speed bus or a receive interrupt command, so that the air conditioning network data transmission layer can retrieve the data from the receive register and process it.

[0103] For example, the data transmission control implementation process is as follows:

[0104] The air conditioning network data transmission layer sends a data transmission command to the transceiver controller to start data transmission. The transceiver controller controls the main transmission register or the secondary transmission register to be ready. The air conditioning network data transmission layer writes the data to be transmitted into the main transmission register or the secondary transmission register through the peripheral high-speed bus.

[0105] After the data protocol packet converter wins the CAN bus control, it sends the data buffered in the main or secondary transmit register through the data stream transmission interface. When the transceiver controller detects that the data transmission is complete, it notifies the air conditioning network data transmission layer of the data transmission completion information through an interrupt command.

[0106] Please continue to refer to this. Figure 6 , Figure 6 This is a schematic diagram of the data transmission layer module provided in an embodiment of the present invention. Figure 6 The diagram shows the management module and functional modules of an outdoor unit. The management module manages all outdoor and indoor slave units, including the application and allocation of IP addresses or equipment project numbers for each air conditioning node, communication initiation, and timing control. The outdoor unit initiates communication on the CAN bus periodically through the management module, for example, by initiating communication (e.g., broadcast / unicast). At this time, only host data is present on the CAN bus. When a slave unit receives a relevant execution command from the host, all slave units on the bus respond by sending their own execution data.

[0107] For example, the host needs to periodically send a round of communication to prevent the CAN bus from being continuously occupied by faulty devices without any idle time. The content managed by the host (outdoor host) for all slave units (including outdoor slave units and indoor slave units) includes:

[0108] (1) The host initiates a new round of communication.

[0109] (2) The slave transceiver determines the communication polarity. The polarity can be switched every preset time period (e.g., 5 seconds) until the correct host data is received, then the communication polarity is fixed and switching stops.

[0110] (3) The outdoor slave unit starts requesting an IP address, and the outdoor host responds and assigns an IP address. After receiving any data from the host, it starts requesting an IP address, requesting once every preset time period (e.g., 3 seconds) until it receives the requested IP address.

[0111] (4) The indoor slave unit starts to request an IP address, and the outdoor host responds and assigns an IP address. After receiving any data from the host, it starts to request an IP address, requesting once every preset time period (e.g., 3 seconds) until it receives the requested IP address.

[0112] (5) The outdoor host controls the outdoor slave unit, and the outdoor slave unit responds. The outdoor slave unit must respond to the query command received by the outdoor host, but may not respond to the control command received by the outdoor host.

[0113] (6) The outdoor host controls and queries the indoor slave unit, and the indoor slave unit responds. The indoor slave unit must respond to the query command received by the outdoor host, but may not respond to the control command received by the outdoor host.

[0114] (7) The debugger controls and queries the indoor slave unit, and the indoor slave unit responds. The indoor slave unit must respond to the query command received by the debugger, but may not respond to the control command received by the debugger.

[0115] (8) The communication module and the unit controller control and query the indoor slave unit, and the indoor slave unit responds. The indoor slave unit must respond to the query command received by the communication module and the unit controller, but may not respond to the control command received by the communication module and the unit controller.

[0116] (9) The simplified central controller controls and queries the indoor slave units, and the indoor slave units respond. The indoor slave units must respond to the query commands received from the simplified central controller, but may not respond to the control commands received from the simplified central controller.

[0117] (10) Detect the operating status of the outdoor slave unit. Send the operating status data of the outdoor slave unit once per communication cycle.

[0118] (11) Detect the operating status of the indoor slave unit. Send the operating status data of the indoor slave unit once per communication round.

[0119] Therefore, through the management module, the project number of the internal node can be quickly queried in the communication access bus system.

[0120] For example, the outdoor host, each outdoor slave unit, and each indoor slave unit are equipped with a digital filter, a data transceiver queue module, and a data transmission control interface connected in sequence. The digital filter is connected to its corresponding transceiver, and the data transmission control interface is connected to its corresponding control module or management module. For example, the control module of each outdoor slave unit or each indoor slave unit is connected to its corresponding data transmission control interface, and the control module of the outdoor host unit is connected to its corresponding management module.

[0121] Specifically, the digital filters of the outdoor host include a device ID / project number filter, a CAN-ID filter, a data packet verification unit, and a CAN adaptive control unit.

[0122] The digital filter, through the CAN adaptive control unit, detects the presence of bus broadcast data. If present, it maintains the current CAN transmit / receive polarity; otherwise, it switches the CAN transmit / receive polarity and continues waiting for bus master broadcast data. If successful, it maintains the switched CAN transmit / receive polarity. If CAN bus data is still not received, it continues polling and switching while waiting for bus data. If the waiting time exceeds a threshold, it reports a CAN transmit / receive fault to the upper layer. This adaptive mechanism enables immediate data connection upon access to bus devices.

[0123] The data packet verification unit is used to verify the integrity of CAN bus data transmission and reception, ensuring high data reliability and the reliability of air conditioner operation status data and OTA (Over-the-Air Technology) function data for intelligent monitoring on the bus.

[0124] The device ID / project number filter and CAN-ID filter are used to filter target frames to reduce the amount of data uploaded to the application layer. By detecting valid data, they improve the efficiency of device data transmission and reception, reduce interference from bus noise data, improve the transmission and reception rate of CAN devices, and enhance the reliability of subsequent data.

[0125] Specifically, the outdoor host's data transceiver queue module is used for sending queues, receiving queues, queue overflow management, and queue transmission / reception timing management. As a supporting module for the data transmission control interface, this data transceiver queue module is called by the digital transmission control interface to achieve data packetization and transmission / reception timing management. Furthermore, this data transceiver queue module also integrates queue overflow management and retransmission management for failed transmissions.

[0126] Specifically, the data transmission control interface of the outdoor unit includes an engineering code or IP address management interface for the indoor slave unit, an air conditioning node operation status interface, an air conditioning node operation control interface, a protocol converter data transceiver interface, a centralized controller or PC data transceiver interface, and an air conditioning node OTA data transceiver interface.

[0127] It should be noted that the data transmission control interface connected to the air conditioning network data application layer adopts a standardized application programming interface (API), which can achieve standard support for different types of application layers, is well compatible with different device types, and supports iterative expansion of devices.

[0128] The air conditioning network data application layer manages its own project number / IP address / online / offline status by calling the indoor slave unit's project code or IP address management interface; it sends its own operating status to the bus / outdoor unit by calling the air conditioning node operating status interface; and it sends operating mode / electronic expansion valve / windshield / protection application controls to the bus / indoor unit by calling the air conditioning operation control interface. The protocol converter acquires and centrally controls device data on the bus system by calling the protocol converter data transceiver interface. The concentrator acquires and controls device data on the bus through the centralized controller / PC data transceiver interface.

[0129] For example, the air conditioning network data application layer can be constructed according to the different types and functions of the devices. It includes the application layer of each air conditioning device, the application layer of the central controller device, the application layer of the protocol converter device, the application layer of the DTU (Data Transfer Unit) device, the application layer of the WIFI central controller device, and the OTA function application layer. Through various standardized API interfaces of the air conditioning network data transmission layer, standard support for different types of application layers can be achieved, which can be well compatible with different device types and support the iterative expansion of devices.

[0130] In summary, compared with existing technologies that use RS485 which cannot effectively expand bus data bandwidth or use CAN without master-slave competition which cannot ensure the data priority of the outdoor unit, this invention ensures both the high priority of the network host and the simultaneous competitive transmission of data from the slave units. It better solves the problem of poor data transmission and reception of air conditioning nodes on the bus, ensures the real-time reliability of control, and supports the expansion of bus data capacity and bandwidth.

[0131] It should be noted that the technical solution of the multi-split air conditioning system described in this invention can also be applied to other multi-node access application scenarios, such as the automotive field.

[0132] The control method for the multi-split air conditioning system provided by the present invention is described below. The control method described below can be referred to in correspondence with the multi-split air conditioning system described above.

[0133] Please refer to Figure 7 , Figure 7 This is a flowchart illustrating the control method for a multi-split air conditioning system provided by the present invention. A control method for a multi-split air conditioning system, the control method being applied to the multi-split air conditioning system described above, the control method comprising:

[0134] Step 710: Based on the preset values ​​of prescaler, CAN clock frequency and baud rate set in the MCU register, obtain the value range of the first target phase buffer segment, the second target phase buffer segment and the target resynchronization compensation width.

[0135] Step 720: Control the register to send data based on the value range, and read the transmission status information of the register to obtain the success rate.

[0136] Step 730: Adjust the values ​​of the first target phase buffer segment, the second target phase buffer segment, and the target resynchronization compensation width according to the success rate to obtain the optimal baud rate setting value.

[0137] The above steps 710 to 730 are described below through an embodiment.

[0138] Please refer to Figure 8 , Figure 8 This is a CAN bit timing diagram for CAN baud rate setting provided in an embodiment of the present invention. When the number of air conditioning nodes on the CAN bus is very large (e.g., >84 nodes) and the CAN data transmission distance is very long (e.g., >2km), the interference signal on the CAN bus is large, the arbitration competition on the CAN bus is very intense, and the quality of CAN chips on the market varies, resulting in low data transmission rate and data congestion on the CAN bus, sub-device disconnection, and data loss problems. Therefore, the present invention provides a control method for a multi-split air conditioning system, which uses an adaptive optimization algorithm for bus competition arbitration failure of multi-split CAN to solve the above problems.

[0139] The CAN bus uses asynchronous serial communication and lacks a separate clock line to ensure clock consistency between transceivers. Each transceiver segments the levels on the bus according to a pre-set baud rate, resulting in baud rate synchronization errors. Therefore, accurate baud rate settings are crucial for stable CAN bus communication. The CAN protocol defines two types of synchronization: hard synchronization and resynchronization (also known as soft synchronization). This invention employs soft synchronization.

[0140] In the CAN protocol, the scalar value of bit period (NOMINAL BIT TIME, NBT) refers to the time required for one (binary) bit to be transmitted on the CAN bus. That is, the scalar value of bit period (also known as "nominal bit time") is the reciprocal of nominal bit rate (NOMINAL BIT RATE, NBR), which refers to the number of bits transmitted per second by an ideal transmitter without resynchronization.

[0141] like Figure 8As shown, the CAN protocol specifies that each bit can be divided into several non-overlapping time segments: SYNC_SEG (synchronization segment), PROP_SEG (propagation time segment), PHASE_SEG1 (first reference phase buffer segment), and PHASE_SEG2 (second reference phase buffer segment). SYNC_SEG is located at the beginning of a bit. CAN-bus specifies that the transition edge is the synchronization signal, but there is a network propagation delay between the transmitting node sending a bit and the receiving node receiving it. PROP_SEG is used to compensate for this propagation delay. Since the sampling point is located between PHASE_SEG1 and PHASE_SEG2, the sampling point position can be adjusted by setting the values ​​of PHASE_SEG1 and PHASE_SEG2 to ensure consistent sampling for each bit. The length adjustment range of the buffer segments (PHASE_SEG1, PHASE_SEG2) is determined by the resynchronization transition width SJW.

[0142] These segments consist of the smallest unit of time called a Time Quantum (TQ). The length of each segment can be represented by an integer time quantum, which is obtained by dividing the system's clock oscillator.

[0143] Therefore, one bit is divided into four segments, and each segment consists of several TQs, which is called bit timing. The number of TQs in one bit, and the number of TQs in each segment, can be arbitrarily set in the bit timing. By setting the bit timing, multiple nodes can sample simultaneously, and the sampling points can be arbitrarily set. That is, each node can obtain different bit rates and sampling accuracies through different configurations. For example, a frequency of 100MHz divided by 4 results in 25MHz, with PRESC=4.

[0144] In practical applications, due to baud rate synchronization errors, it is necessary to set the baud rate, which requires defining the CAN control register (e.g., ...). Figure 8 As shown), the scalar value of one bit period is divided into a first target phase buffer segment SEGMENGT1 and a second target phase buffer segment SEGMENT2. See below:

[0145] NBT=SYNC_SEG+PROP_SEG+PHASE_SEG1+PHASE_SEG2;

[0146] =SEGMENGT1+SEGMENT2.

[0147] In this context, PHASE_SEG1 will be abbreviated as SEG_1, PHASE_SEG2 as SEG_2, SEGMENGT1 as SEG1, and SEGMENT2 as SEG2.

[0148] The CAN bit timing register (CAN_BTR) is used to set parameters such as SEG1, SEG2, BRP (Baud Rate Prescaler), and SJW (reSynchronization Jump Width), which directly determine the CAN baud rate.

[0149] For example, in step 710 above, the step of obtaining the value range of the first target phase buffer segment, the second target phase buffer segment, and the target resynchronization compensation width based on the preset values ​​of prescaler, CAN clock frequency, and baud rate set in the MCU register includes:

[0150] Step 711: Obtain the time quantum based on the prescaler and CAN clock frequency set in the MCU register.

[0151] The formula for calculating this time quantum is:

[0152] TQ = (PRESC + 1) / f can_clk TQ represents time quantum, PRESC represents the prescaler set in the MCU register, which can be set via the PRESC bit in the BT register. can_clk Indicates the CAN clock frequency.

[0153] For example, the clock frequency used in CAN communication is can_clk (e.g., Figure 5 The clock source is an external oscillator (e.g., its frequency is 8MHz), so for example, the CAN clock frequency Fre = 50 prescaler and can_clk = 160KHz can be set.

[0154] It should be noted that TQ equals one CAN clock cycle. Generally, TQ is calculated first when determining the baud rate. The frequency is equal to the reciprocal of the cycle. CAN clock frequency = 1 / TQ = 1 / CAN clock cycle. Bit time equals the sum of the times of the above segments, and baud rate equals the reciprocal of bit time. Therefore, in the CAN bus, communication at different baud rates is achieved by controlling the bit timing register in the CAN air conditioning node.

[0155] Step 712: Based on the preset values ​​of time quantum and baud rate, and according to the baud rate calculation formula, obtain the first value range of the first target phase buffer segment, the second target phase buffer segment, and the target resynchronization compensation width.

[0156] It should be noted that the value range of step 710 above includes a first value range (see step 712) and a second value range (see step 734). The first value range is obtained based on the preset baud rate value and the chip's reference value, while the second value range is obtained based on the actual measured error value and adjustment.

[0157] When starting the system, you need to set a preset value for the CAN baud rate of the indoor air conditioner unit (e.g., set the preset value to 20Kbps).

[0158] The baud rate calculation formula is as follows:

[0159] BT=T SEG1 +T SEG2 = ((SEG_1+2)+(SEG_2+1))×TQ, where BT represents bit time (bit time is the reciprocal of baud rate), SEG1 represents the first target phase buffer segment, SEG2 represents the second target phase buffer segment, SEG_1 represents the first reference phase buffer segment, SEG_2 represents the second reference phase buffer segment, and T represents time.

[0160] It should be noted that the SYNC_SEG segment in the above formula is a hardware identification transition bit and is not included in the baud rate calculation formula, so the PROP_SEG segment is (2+1)×TQ=3TQ.

[0161] The reference value ranges for SEG_1, SEG_2, and SJW_1 in the above baud rate calculation formula are as follows:

[0162] 0 ≤ SEG_1 ≤ 63, 0 ≤ SEG_2 ≤ 7, 0 ≤ SJW_1 ≤ 7, and SEG_2 + 1 ≤ SEG_1, SJW_1 ≤ SEG_2. Here, SJW_1 represents the reference resynchronization compensation width, which is the design range given by the chip, as shown in the table below:

[0163]

[0164] Therefore, based on the above baud rate calculation formula, and according to the time quantum TQ, the baud rate preset value 1 / BT, and the reference value range (SEG_1, SEG_2, SJW_1), the first target phase buffer segment SEG1, the second target phase buffer segment SEG2, and the first value range of the target resynchronization compensation width SJW are obtained.

[0165] For example, in step 720 above, the step of controlling the register to send data based on the value range includes:

[0166] Step 721: Based on the first value range, take the set values ​​of the first target phase buffer segment SEG1, the second target phase buffer segment SEG2, and the target resynchronization compensation width SJW and write them into the register (also known as the baud rate register BT).

[0167] The registers include a transmit register and a receive register, and the transmit register may also include a main transmit register and a secondary transmit register (e.g., ...). Figure 5 (As shown).

[0168] Step 722: Set the transmit register to CAN transmit data mode and set the corresponding receive register to CAN receive data mode.

[0169] Step 723: Monitor the CAN bus for CAN communication data at preset time intervals. If no communication data is found, proceed to step 724; otherwise, proceed to step 725.

[0170] Step 724: If no CAN communication data is found, switch the polarity of the CAN bus and return to step 723 to continue listening.

[0171] Step 725: If CAN communication data exists, the transceiver controller writes the received CAN communication data into the transmit register and controls the transmit register to transmit the data.

[0172] For example, in step 720 above, the step of reading the transmission status information of the register to obtain the success rate includes:

[0173] Step 726: Read the transmission status information of the transmission register, calculate the success rate based on the number of data transmitted and the number of data successfully transmitted within the time window, and calculate the error value based on the success rate.

[0174] Specifically, the criteria for determining whether data was sent successfully are as follows:

[0175]

[0176]

[0177] The formulas for calculating the success rate and error value are as follows:

[0178] Fm = Tount1 / Tcount0 * 100%;

[0179] ΔFm = 100% - Fm;

[0180] Where Fm represents the success rate, Tount1 represents the number of data successfully sent, Tcount0 represents the number of data sent, and ΔFm represents the error value.

[0181] For example, in step 730 above, the step of adjusting the values ​​of the first target phase buffer segment, the second target phase buffer segment, and the target resynchronization compensation width according to the success rate to obtain the optimal baud rate setting includes:

[0182] Step 731: Based on the error value and the preset baud rate value, and according to the baud rate calculation formula, increase the first target phase buffer segment and the second target phase buffer segment, and then decrease the time quantum to perform fuzzy adjustment.

[0183] For example, assuming BT is a baud rate of 20K, the analog-to-digital conversion is adjusted based on the error value ΔFm, for example, by positively increasing the first target phase buffer segment and the second target phase buffer segment, thereby decreasing the time quantum, i.e., SEG1+, SEG2+, TQ-.

[0184] Step 732: Based on the result of the fuzzy adjustment, determine whether the error value has decreased. If the error value has increased, proceed to step 733; if the error value has decreased, proceed to step 734.

[0185] Step 733: If the error value increases, then adjust the first target phase buffer segment and the second target phase buffer segment according to the baud rate calculation formula, and then increase the time quantum for fuzzy adjustment.

[0186] For example, if the error value increases, it indicates that the direction of the fuzz adjustment in step 731 is incorrect, and a positive downward fuzz adjustment should be performed, which lowers the first target phase buffer segment and the second target phase buffer segment and then increases the time quantum, namely SEG1-, SEG2-, TQ+.

[0187] Step 734: Perform proportional-integral-derivative (PID) adjustment that keeps the time quantum constant according to the fuzzy adjustment method that can reduce the error value, so as to obtain the adjusted values ​​of the second target phase buffer segment and the target resynchronization compensation width.

[0188] It should be noted that by obtaining the adjustment values ​​of the adjusted second target phase buffer segment and the target resynchronization compensation width, the adjustment value of the adjusted first target phase buffer segment can also be obtained.

[0189] Step 734: Based on the adjustment value, determine the second value range for the second target phase buffer segment and the target resynchronization compensation width. Specifically:

[0190] First, assume the deviation of the clock frequency from the expected frequency value is the reference clock error (Δf). FCLK,max / min represents the maximum or minimum reference clock frequency, and FCLK,rat represents the rated reference clock frequency. The clock cycle will also have an error. TSCL,min represents the minimum system clock cycle, TSCL,max represents the maximum system clock cycle, and TSCL,rat represents the rated system clock cycle. Since Δf << 1, an approximate value can be used.

[0191] TSCL,min=(TSCL,rat) / (1+Δf)≈TSCL,rat×(1-Δf);

[0192] TSCL,max=(TSCL,rat) / (1-Δf)≈TSCL,rat×(1+Δf).

[0193] Secondly, calculate the transmission delay error. The transmission delay time is determined by the physical bus delay (tBUS), the bus driver delay (Ttran), and the transmission delay of other devices (Toth). Other devices include communication controllers, isolation mechanisms, etc.

[0194] tprop=2×(tBUS+ttran+toth);

[0195] The scalar value of transmission delay PROP = tprop / fcan_clk.

[0196] Then, calculate the scalar value of the bit period (NBT) =

[0197] Tbit / TSCL=SYNC_SEG+TSEG1+TSEG2;

[0198]

[0199] SJW max =4;

[0200] TSEG2 min =MAX{2,SJW};

[0201]

[0202] Δf is obtained through chip frequency oscillator calibration calculation, that is, through chip clock calibration calculation.

[0203] For example, in step 730 above, the step of adjusting the values ​​of the first target phase buffer segment, the second target phase buffer segment, and the target resynchronization compensation width according to the success rate to obtain the optimal baud rate setting value further includes:

[0204] Step 735: Based on the second value range, assign values ​​to the second target phase buffer segment and the target resynchronization compensation width.

[0205] For example, the second range of values ​​for determining the second target phase buffer segment and the target resynchronization compensation width is: SEG2 = 1, 2, 3, SJW = 1, 2, 3; then

[0206] When SEG2 = 1, iterate through SJW;

[0207] When SEG2 = 2, iterate through SJW;

[0208] When SEG2=3, traverse SJW.

[0209] The purpose of traversal is to select the set of values ​​with the smallest error (e.g., an error of 0%) from the traversal results and assign it to the register.

[0210] Step 736: Based on the assigned value, determine whether the error value has decreased and whether it is within the adjustment period of the optimal baud rate setting.

[0211] If the error value decreases and is within the adjustment period of the optimal baud rate setting, proceed to step 737; otherwise, return to step 736.

[0212] Step 737: If the error value decreases and is within the adjustment period of the optimal baud rate setting, then when the error value is lower than or equal to the first preset threshold (for example, the first preset threshold is 0%), the first target phase buffer segment, the second target phase buffer segment, the target resynchronization compensation width, and the time quantum are determined to be the target assignment.

[0213] If a set of values ​​with an error of 0% is found in the traversal results, then this set of values ​​is used as the target value and assigned to the register.

[0214] Step 738: Based on the target value, obtain the optimal baud rate setting value according to the baud rate calculation formula.

[0215] For example, after performing step 738, the control method for the multi-split air conditioning system further includes:

[0216] Step 739: Determine whether the adjustment period for determining the optimal baud rate setting exceeds the second preset threshold (e.g., the second preset threshold is 30 seconds).

[0217] If the adjustment period for the optimal baud rate setting exceeds the second preset threshold, then return to step 735 above, that is, assign values ​​to the second target phase buffer segment and the target resynchronization compensation width based on the second value range. In other words, this invention adjusts the baud rate setting every second preset threshold to ensure reliable data transmission.

[0218] Understandably, in the CAN communication protocol, the communication baud rate, the sampling position and number of samples per bit cycle can all be set by the user. The design philosophy of CAN is to provide users with flexibility in optimizing network communication performance during practical applications. To optimize performance by setting the baud rate, it's necessary to understand the relationship between bit timing parameters, reference clock errors, and signal delays within the system. If the sampling position within a bit cycle is further back, a larger signal transmission delay can be tolerated, and correspondingly, the bus transmission distance can be extended; conversely, if the sampling position within a cycle is closer to the middle, reference clock errors between system nodes can be tolerated. However, this is clearly contradictory. To reconcile this contradiction, the bit timing parameters need to be adaptively and dynamically optimized.

[0219] Therefore, by optimizing the baud rate setting in the control method of the multi-split air conditioning system described in this invention, even when the number of indoor unit nodes reaches a preset value (e.g., 80) or more, the probability of indoor unit nodes going offline can be reduced in the bus system, and when multiple nodes are transmitting data concurrently, the probability of data delay or even loss at indoor unit nodes can also be reduced.

[0220] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-split air conditioning system, characterized in that, The system includes: The air conditioning network data link layer is configured with a corresponding transceiver for each air conditioning node. Multiple air conditioning nodes include an outdoor host, multiple outdoor slaves, and multiple indoor slaves. The transceiver of the outdoor host communicates with the transceivers of each outdoor slave and each indoor slave via a CAN bus. The air conditioning network data transmission layer is equipped with a management module and a function module for the outdoor unit, and a function module is also equipped for each outdoor slave unit and each indoor slave unit. The transceiver of the outdoor unit, the transceiver of the outdoor slave unit, and the transceiver of the indoor slave unit all communicate with their respective function modules. The air conditioning network data application layer is equipped with a control module for monitoring the operating status of the outdoor unit, each outdoor slave unit and each indoor slave unit. The control module of the outdoor unit communicates with its corresponding management module, and the control modules of each outdoor slave unit and each indoor slave unit communicate with their respective functional modules. Each air conditioning node is equipped with an MCU at the air conditioning network data link layer, and the MCU has at least one register; The multi-split air conditioning system is configured to perform the following control method: Based on the preset values ​​of prescaler, CAN clock frequency and baud rate set in the register of the MCU, the value range of the first target phase buffer segment, the second target phase buffer segment and the target resynchronization compensation width are obtained. The register is controlled to send data based on the value range, and the sending status information of the register is read to obtain the success rate; The values ​​of the first target phase buffer segment, the second target phase buffer segment, and the target resynchronization compensation width are adjusted according to the success rate to obtain the optimal baud rate setting.

2. The multi-split air conditioning system according to claim 1, characterized in that, Each air conditioning node is also equipped with a transceiver chip circuit and a CAN adaptive control circuit at the air conditioning network data link layer. The transceiver chip circuit includes a first transceiver chip and a second transceiver chip. The CAN adaptive control circuit controls the first transceiver chip or the second transceiver chip to be turned on by the MCU outputting an enable signal to realize the polarity switching of the CAN bus.

3. The multi-split air conditioning system according to claim 2, characterized in that, The MCU is equipped with a data stream receiving interface, a data stream sending interface, a data protocol packet converter, a data receiving filter, a receiving register, a main sending register, a secondary sending register, a clock prescaler, and a transceiver controller. The data stream receiving interface receives data packets from the CAN bus, and the data packet converter unpacks the data packets and inputs them to the data receiving filter to filter the CAN ID. After filtering the CAN ID data, the data is stored in the receiving register. The transceiver controller uses the peripheral high-speed bus or receives an interrupt command to allow the air conditioning network data transmission layer to retrieve the data from the receiving register and perform data processing. The air conditioning network data transmission layer sends a data transmission command to the transceiver controller to start data transmission. The transceiver controller controls the main transmission register or the secondary transmission register to be ready. The air conditioning network data transmission layer writes the data to be transmitted into the main transmission register or the secondary transmission register through the peripheral high-speed bus. After the data protocol packet converter acquires control of the CAN bus, it sends the data buffered in the main transmit register or the secondary transmit register through the data stream transmission interface. When the transceiver controller detects that the data transmission is complete, it notifies the air conditioning network data transmission layer of the data transmission completion information through an interrupt command.

4. The multi-split air conditioning system according to claim 1, characterized in that, The management module of the outdoor unit is used to manage all outdoor and indoor slave units. The management includes the application and allocation of IP addresses for each air conditioning node, communication initiation, and timing control. The outdoor unit initiates communication on the CAN bus periodically through the management module.

5. The multi-split air conditioning system according to claim 4, characterized in that, The outdoor main unit, each outdoor slave unit and each indoor slave unit are equipped with a digital filter, a data transceiver queue module and a data transmission control interface connected in sequence. The digital filter is connected to its corresponding transceiver, and the data transmission control interface is connected to its corresponding control module or management module. The outdoor unit's digital filter is used for filtering device IDs or project numbers, filtering CAN IDs, data packet verification, and CAN adaptive control. The data transceiver queue module of the outdoor host is used for sending queues, receiving queues, queue overflow management, and queue sending and receiving timing management. The data transmission control interface of the outdoor unit includes the engineering code or IP address management interface of the indoor slave unit, which includes the air conditioner node operation status interface, the air conditioner node operation control interface, the protocol converter data transceiver interface, the centralized controller or PC data transceiver interface, and the air conditioner node OTA data transceiver interface.

6. The multi-split air conditioning system according to claim 1, characterized in that, The air conditioning network data application layer includes the application layer of each air conditioning device, the application layer of the central controller device, the application layer of the protocol converter device, the application layer of the DTU device, the application layer of the WIFI central controller device, and the OTA function application layer.

7. The multi-split air conditioning system according to claim 2, characterized in that, Each transceiver is also equipped with a CAN bus access port, a bus protection circuit, a terminal resistor, and an isolation chip circuit. Each transceiver is connected to the CAN bus through its own CAN bus access port. The CAN bus access port is connected to the bus protection circuit. The bus protection circuit is connected to the first transceiver chip and the second transceiver chip respectively. The MCU is connected to the first transceiver chip and the second transceiver chip respectively through the isolation chip circuit.

8. The multi-split air conditioning system according to claim 7, characterized in that, The CAN bus access port includes a first port, a second port, a third port, and a terminal resistor. The first ends of the first port, the second port, and the third port are all connected to the bus protection circuit. The second ends of the first port and the second port are both connected to the CAN bus. The second end of the third port is connected to the terminal resistor.

9. The multi-split air conditioning system according to claim 7, characterized in that, The CAN adaptive control circuit includes a first resistor (R56), a second resistor (R57), a third resistor (R61), a first transistor (Q2), a second transistor (Q5), and a third transistor (Q6). The enable terminal of the isolation chip circuit is connected to the first terminal of the first resistor (R56) and the second terminal of the third transistor (Q6). The second terminal of the first resistor (R56) is connected to the base of the first transistor (Q2) and the first terminal of the second resistor (R57). The emitter of the first transistor (Q2) and the second terminal of the second resistor (R57) are both grounded. The collector of the first transistor (Q2) is connected to the first terminal of the third resistor (R61) and the second terminal of the second transistor (Q5). The third terminal of the second transistor (Q5) is connected to the base of the first transistor (Q2) and the second terminal of the second transistor (Q6). The third terminal of the first transceiver chip (IC10) is connected to the VCC pin and the NC pin of the second transceiver chip (IC11), respectively. The third terminal of the third transistor (Q6) is connected to the VCC pin and the NC pin of the second transceiver chip (IC11), respectively. The TXD pin of the first transceiver chip (IC10) is connected to the TXD pin of the second transceiver chip (IC11). The RXD pin of the first transceiver chip (IC10) is connected to the RXD pin of the second transceiver chip (IC11). The CANH pin of the first transceiver chip (IC10) is connected to the CANL pin of the second transceiver chip (IC11) and the bus protection circuit, respectively. The CANL pin of the first transceiver chip (IC10) is connected to the CANH pin of the second transceiver chip (IC11) and the bus protection circuit, respectively.

10. The multi-split air conditioning system according to claim 9, characterized in that, The isolation chip circuit includes an isolation chip (IC8). The TX-CAN pin of the MCU is connected to the INA pin of the isolation chip (IC8) through a fifth resistor (R52). The RX-CAN pin of the MCU is connected to the OUTC pin of the isolation chip (IC8) through a sixth resistor (R54). The OUTA pin of the isolation chip (IC8) is connected to the TXD pin of the first transceiver chip (IC10) and the TXD pin of the second transceiver chip (IC11). The INC pin of the isolation chip (IC8) is connected to the RXD pin of the first transceiver chip (IC10) and the RXD pin of the second transceiver chip (IC11). The OUTB pin of the isolation chip (IC8) is connected to the enable terminal (CS) of the CAN adaptive control circuit to output an enable signal to the CAN adaptive control circuit.

11. A control method for a multi-split air conditioning system, characterized in that, The control method is applied to the multi-split air conditioning system as described in any one of claims 1 to 10, and the control method includes: Based on the preset values ​​of prescaler, CAN clock frequency and baud rate set in the MCU register, the value ranges of the first target phase buffer segment, the second target phase buffer segment and the target resynchronization compensation width are obtained. The register is controlled to send data based on the value range, and the sending status information of the register is read to obtain the success rate; The values ​​of the first target phase buffer segment, the second target phase buffer segment, and the target resynchronization compensation width are adjusted according to the success rate to obtain the optimal baud rate setting.

12. The control method for a multi-split air conditioning system according to claim 11, characterized in that, The step of obtaining the value ranges of the first target phase buffer segment, the second target phase buffer segment, and the target resynchronization compensation width based on the preset values ​​of prescaler, CAN clock frequency, and baud rate set in the MCU register includes: The time quantum is obtained based on the prescaler and CAN clock frequency set in the MCU registers; Based on the preset values ​​of time quantum and baud rate, and according to the baud rate calculation formula, the first value range of the first target phase buffer segment, the second target phase buffer segment, and the target resynchronization compensation width is obtained; The formula for calculating this time quantum is: TQ=(PRESC+1) / f can_clk TQ represents time quantum, PRESC represents the prescaler set in the MCU register, and f can_clk Indicates the CAN clock frequency; The baud rate calculation formula is as follows: BT=T SEG1 +T SEG2 = ((SEG_1+2)+(SEG_2+1))×TQ, where BT represents the baud rate, SEG1 represents the first target phase buffer segment, SEG2 represents the second target phase buffer segment, SEG_1 represents the first reference phase buffer segment, SEG_2 represents the second reference phase buffer segment, and T represents time.

13. The control method for a multi-split air conditioning system according to claim 12, characterized in that, The step of obtaining the first value range of the first target phase buffer segment, the second target phase buffer segment, and the target resynchronization compensation width based on the preset values ​​of the time quantum and baud rate, and according to the baud rate calculation formula, includes: The first reference phase buffer segment and the second reference phase buffer segment are set through the first reference phase buffer segment bit and the second reference phase buffer segment bit in the register, and the corresponding reference value range is: 0≤SEG_1≤63, 0≤SEG_2≤7, 0≤SJW_1≤7, and SEG_2+1≤SEG_1,SJW_1≤SEG_2,SJW_1 represents the reference resynchronization compensation width; Based on the baud rate calculation formula, and according to the time quantum, the preset baud rate value, and the reference value range, the first target phase buffer segment, the second target phase buffer segment, and the first value range of the target resynchronization compensation width are obtained.

14. The control method for a multi-split air conditioning system according to claim 13, characterized in that, The step of controlling the register to send data based on the value range includes: Based on the first value range, the set values ​​of the first target phase buffer segment, the second target phase buffer segment, and the target resynchronization compensation width are written into the register, which includes a transmit register and a receive register. Set the transmit register to CAN transmit data mode and the corresponding receive register to CAN receive data mode; Monitor the CAN bus for CAN communication data at preset time intervals; If no CAN communication data is available, the polarity of the CAN bus is switched and listening continues; if CAN communication data is available, the received CAN communication data is written into the transmit register and the transmit register is controlled to transmit the data.

15. The control method for a multi-split air conditioning system according to claim 14, characterized in that, The step of reading the transmission status information of the register to obtain the success rate includes: Read the transmission status information of the transmission register, calculate the success rate based on the number of data transmitted and the number of data successfully transmitted within the time window, and calculate the error value based on the success rate; The formulas for calculating the success rate and error value are as follows: Fm = Tount1 / Tcount0 * 100%; △Fm = 100% - Fm; Where Fm represents the success rate, Tount1 represents the number of data successfully sent, Tcount0 represents the number of data sent, and △Fm represents the error value.

16. The control method for a multi-split air conditioning system according to claim 15, characterized in that, The step of adjusting the values ​​of the first target phase buffer segment, the second target phase buffer segment, and the target resynchronization compensation width according to the success rate to obtain the optimal baud rate setting includes: Based on the error value and the preset baud rate value, and according to the baud rate calculation formula, the first target phase buffer segment and the second target phase buffer segment are increased, and the time quantum is decreased to perform fuzzy adjustment; Based on the result of the fuzzy adjustment, it is determined whether the error value has decreased; If the error value increases, the first target phase buffer segment and the second target phase buffer segment are lowered and the time quantum is increased according to the baud rate calculation formula to perform fuzzy adjustment. Based on the fuzzy adjustment method that can reduce the error value, proportional-integral-derivative adjustment is performed while keeping the time quantum constant, so as to obtain the adjusted values ​​of the second target phase buffer segment and the target resynchronization compensation width; Based on the adjustment value, a second range of values ​​for the second target phase buffer segment and the target resynchronization compensation width is determined.

17. The control method for a multi-split air conditioning system according to claim 16, characterized in that, The step of adjusting the values ​​of the first target phase buffer segment, the second target phase buffer segment, and the target resynchronization compensation width according to the success rate to obtain the optimal baud rate setting also includes: Based on the second value range, assign values ​​to the second target phase buffer segment and the target resynchronization compensation width; Based on the assigned value, determine whether the error value has decreased and whether it is within the adjustment period of the optimal baud rate setting; If the error value decreases and is within the adjustment period of the optimal baud rate setting, then when the error value is lower than or equal to the first preset threshold, the first target phase buffer segment, the second target phase buffer segment, the target resynchronization compensation width, and the time quantum are determined to be the target assignment. The optimal baud rate setting value is obtained according to the target value and the baud rate calculation formula.

18. The control method for a multi-split air conditioning system according to claim 17, characterized in that, After the step of determining the optimal baud rate setting value according to the baud rate calculation formula based on the target assignment, the control method further includes: Determine whether the adjustment period for determining the optimal baud rate setting exceeds the second preset threshold; If it is determined that the adjustment period of the most baud rate setting exceeds the second preset threshold, then return to the step of assigning values ​​to the second target phase buffer segment and the target resynchronization compensation width based on the second value range.

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