Three-axis driving frequency converter, air conditioner electric control box and air conditioner equipment

Abstract

The utility model discloses a three-axis drive frequency converter, an air conditioner electric control box and air conditioning equipment, relates to the technical field of power electronics, is used for providing a frequency conversion control function, and provides the three-axis drive frequency converter aiming at the problems caused by the scheme that three split-type frequency converters are adopted for a compressor, a fan and a water pump at present. Three original split-type frequency converters corresponding to a compressor, a fan and a water pump in the air conditioning equipment are achieved through a one-to-one single-shaft frequency conversion module and a one-to-two double-shaft frequency conversion module, and the single-shaft frequency conversion module and the double-shaft frequency conversion module are integrated on the same mainboard. Three motor devices can be simultaneously controlled to operate through one circuit board. According to the scheme, the problem that the overall size is increased due to a split-type frequency converter is solved, connecting wire harnesses between the frequency converters are reduced, the material cost of air conditioning equipment can be controlled, and the overall production efficiency can be improved.

Description

Technical Field

[0001] This utility model relates to the field of power electronics, and in particular to a three-axis drive frequency converter, an air conditioner control box, and an air conditioner device. Background Technology

[0002] In many fields, including industry, there is a common requirement for complete equipment: energy saving. For air conditioning equipment, compressors, fans, and water pumps are gradually shifting from fixed-frequency control to variable-frequency control based on these energy-saving requirements.

[0003] However, in the process of realizing this utility model, the inventors discovered that the existing technology has at least the following problems: Components such as compressors, fans, and water pumps are all independent power electronic devices, connected and combined with each other via cables to meet the application requirements of the overall industrial equipment. These independent power electronic devices all require corresponding frequency converters for control, resulting in an increasing number of frequency converter devices required inside the overall control box, a larger overall control box design, and an increase in the number of connection harnesses for the frequency converter devices, ultimately increasing the material cost of the entire equipment.

[0004] Therefore, those skilled in the art urgently need a three-axis drive frequency converter to solve the problems caused by the need for frequency conversion control of compressors, fans, and water pumps in air conditioning equipment. Utility Model Content

[0005] The purpose of this invention is to provide a three-axis drive frequency converter, an air conditioning control box, and an air conditioning device to solve the problems of large size and high cost of wiring harness materials in current air conditioning control boxes.

[0006] To solve the above-mentioned technical problems, this utility model provides a three-axis drive frequency converter, including: a dual-axis frequency converter module and a single-axis frequency converter module;

[0007] The single-axis frequency converter module and the dual-axis frequency converter module are integrated on the same motherboard and share the power input terminal of the motherboard for power supply. The single-axis frequency converter module is used to perform frequency conversion control on one of the compressor, fan and water pump, and the dual-axis frequency converter module is used to perform frequency conversion control on the other two of the compressor, fan and water pump.

[0008] In one possible embodiment, the single-axis inverter module is used for inverter control of the compressor, and the dual-axis inverter module is used for inverter control of the fan and the water pump.

[0009] In one possible embodiment, it further includes: an AFE module;

[0010] The AFE module is used to rectify and convert the three-phase power input from the outside, and provides two DC power inputs to supply the single-axis frequency converter module and the dual-axis frequency converter module.

[0011] In one possible embodiment, the AFE module is mounted on an AFE circuit board, which is connected to the main board to form a single circuit board. The AFE module is electrically connected to the single-axis inverter module and the dual-axis inverter module via copper busbars and cables.

[0012] In one possible embodiment, it further includes: a communication module, which is connected to a communication terminal on the AFE circuit board and the motherboard;

[0013] The communication terminal on the motherboard is a common terminal for the single-axis frequency converter module and the dual-axis frequency converter module to communicate with external devices; the communication terminal on the AFE circuit board is a port for the AFE module to communicate with external devices.

[0014] In one possible embodiment, the communication module includes: an analog input terminal, a digital input terminal, an analog output terminal, and an external communication terminal for communicating with external devices, and an internal communication terminal for communicating with the single-axis frequency converter module, the dual-axis frequency converter module, and the AFE module.

[0015] In one possible embodiment, the communication module is a PLC communication module and is mounted on a PLC communication board;

[0016] The PLC communication board is positioned above the AFE circuit board and is fixedly connected to the AFE circuit board.

[0017] In one possible embodiment, the PLC communication board and the AFE circuit board are fixedly connected by spacers;

[0018] The length of the spacer column is greater than the maximum vertical height of the electrical components on the AFE circuit board, but less than the maximum vertical height of the electrical components on the motherboard.

[0019] To solve the above-mentioned technical problems, this application also provides an air conditioner control box, including: a three-axis drive frequency converter and a control box housing as described above.

[0020] To solve the above-mentioned technical problems, this application also provides an air conditioning device, including: an air conditioning control box as described above, and a compressor, a fan and a water pump connected to the air conditioning control box.

[0021] This utility model provides a three-axis drive frequency converter. Through integrated design, it combines the three separate frequency converters originally used in air conditioning equipment (corresponding to the compressor, fan, and water pump) into a single-axis frequency converter module (one-to-one) and a dual-axis frequency converter module (one-to-two). The single-axis and dual-axis frequency converter modules are integrated onto a single motherboard, enabling simultaneous control of all three motors from a single circuit board. This solution solves the problem of increased overall size caused by separate frequency converters, reduces the wiring harnesses between frequency converters, helps control material costs for air conditioning equipment, and improves overall production efficiency.

[0022] The air conditioning control box and air conditioning equipment provided in this application correspond to the above-mentioned three-axis drive frequency converter and have the same effect. Attached Figure Description

[0023] To more clearly illustrate the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A mainboard structure diagram of a three-axis drive frequency converter provided by this utility model;

[0025] Figure 2 A schematic diagram of an integrated board structure for a three-axis drive frequency converter provided by this utility model;

[0026] Figure 3 A schematic diagram of an integrated board structure for a three-axis drive frequency converter provided by this utility model;

[0027] Among them, 10 is the main board, 11 is the dual-axis frequency converter module, 12 is the single-axis frequency converter module, 20 is the AFE circuit board, 21 is the AFE module, and 30 is the PLC communication board. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] The core of this utility model is to provide a three-axis drive frequency converter, an air conditioning control box, and an air conditioning device.

[0030] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] A complete unit refers to an electromechanical product that is either a set or a single unit. For example, an air conditioning unit refers to a complete set of equipment consisting of a compressor, a fan, a water pump, and electrical electronic equipment such as a control box that controls the first three components, all connected and combined by cables.

[0032] Due to increasing energy-saving requirements in industrial applications, air conditioning equipment needs to use variable frequency drives (VFDs) to control the compressor, fan, and water pump. In related technologies, each of these independent power electronic devices—compressor, fan, and water pump—requires a separate VFD controller. This means that the air conditioning unit's control box needs to house three separate VFDs for driving and controlling the compressor, fan, and water pump. This inevitably leads to a more complex electrical connection structure, and the control box needs to be larger to accommodate the three VFDs. Consequently, this creates higher barriers to entry for end-users in terms of installation and use of air conditioning equipment, including but not limited to: increased requirements for the installation environment, increased installation difficulty, and increased material costs for the entire unit.

[0033] Therefore, to solve the above problems, this application provides a three-axis drive frequency converter, such as... Figure 1 As shown, it includes: a dual-axis frequency converter module 11 and a single-axis frequency converter module 12.

[0034] The single-axis inverter module 12 and the dual-axis inverter module 11 are integrated on the same motherboard 10 and share the power input terminal of the motherboard 10 to connect to the power supply. The single-axis inverter module 12 is used to perform frequency conversion control on one of the compressor, fan and water pump, and the dual-axis inverter module 11 is used to perform frequency conversion control on the other two of the compressor, fan and water pump.

[0035] Specifically, the aforementioned single-axis inverter module 12 can be implemented by a single-axis inverter, that is, used for inverter drive control of one motor. Similarly, the dual-axis inverter module 11 can be implemented by a dual-axis inverter, that is, used for inverter drive control of two motors. Therefore, the single-axis inverter module 12 and the dual-axis inverter module 11 described above can meet the inverter drive control requirements of the air conditioning equipment for the three power electronic devices: compressor, fan, and water pump.

[0036] It should be noted that a single-axis drive module can implement variable frequency drive control for one motor, meaning the controlled object can be any one of the compressor, fan, or water pump. Similarly, a dual-axis drive module can implement variable frequency drive control for two motors, thus handling the variable frequency drive control of the remaining two power electronic devices in the compressor, fan, and water pump. However, this embodiment does not impose restrictions on the specific correspondence between the single-axis and dual-axis drive modules and the compressor, fan, and water pump; it can be freely determined according to actual engineering application needs, circuit design requirements, and other requirements.

[0037] However, in one possible application scenario, the power level required to implement variable frequency drive control of a compressor is greater than that required to implement variable frequency drive control of a fan or water pump. Therefore, this embodiment provides a suitable implementation scheme for this possible application scenario:

[0038] The single-axis inverter module 12 is used for inverter control of the compressor, and the dual-axis inverter module 11 is used for inverter control of the fan and water pump.

[0039] In this embodiment, the single-axis inverter module 12 independently implements the inverter drive control of the compressor with a relatively higher power level, while the dual-axis inverter module 11 implements the inverter drive control of the fan and water pump with a relatively lower power level. This makes the power levels of the single-axis inverter module 12 and the dual-axis inverter module 11 integrated on the same motherboard 10 more balanced, thereby facilitating circuit design and wiring layout.

[0040] It should also be noted that, in this embodiment, the single-axis inverter module 12 and the dual-axis inverter module 11 are integrated on a single motherboard 10, and their common ports, such as the power input terminal (e.g., Figure 2 The 24V input and 720V DC input in the model, as well as the communication terminals that may exist in subsequent embodiments, can share a single port on the motherboard 10. However, their unique output ports still need to be configured separately. For example, the single-axis inverter module 12 and the dual-axis inverter module 11 correspond to the three sets of output ports of the compressor, fan, and water pump, respectively (e.g., ...). Figure 2 Center: U, V, W; U1, V1, W1; U2, V2, W2).

[0041] On the other hand, this embodiment also provides a further implementation scheme, such as... Figure 2 As shown, the three-axis drive inverter also includes an AFE (Active Front End, which functions as a rectification / feedback unit) module 21. The AFE module 21 is used to rectify and convert the externally input three-phase power, providing two DC power inputs to supply the single-axis inverter module 12 and the dual-axis inverter module 11.

[0042] It should be noted that the two DC power inputs here are not provided separately to the single-axis inverter module 12 and the dual-axis inverter module 11. As can be seen from the above embodiments, the single-axis inverter module 12 and the dual-axis inverter module 11 can be implemented by single-axis inverters and dual-axis inverters, respectively. That is, each inverter module is equivalent to one control circuit section + one or two drive circuit sections. The power supply used by the control circuit section is used to power the control circuit section, especially the control devices such as the microcontroller that play a control role. Generally, a lower voltage level power input such as 24V DC is required, which can be called the control power input. The drive circuit section, on the other hand, depends on the driving needs of the driven object (compressor, fan, water pump). The power input it is connected to generally requires a higher voltage level power input such as 720V DC, which can be called the drive power input. Therefore, the AFE module 21 is needed to convert the external power supply such as AC mains into two power inputs that can be used by the single-axis inverter module 12 and the dual-axis inverter module 11. Furthermore, these two power inputs are shared by the single-axis inverter module 12 and the dual-axis inverter module 11, with each power input passing through a corresponding power input terminal on the main board 10 (e.g., Figure 2 Connect the 24V and DC-IN pins.

[0043] The implementation scheme provided in this embodiment provides harmonic mitigation function to the external power input through AFE module 21, which can effectively suppress harmonic components in the power grid and improve the power factor, thereby providing better power input conditions for the three-axis drive frequency converter to control the operation of the compressor, fan and water pump, and improving the overall working efficiency of the whole equipment.

[0044] Furthermore, regarding the settings of the aforementioned AFE module 21, as follows: Figure 3 As shown, this embodiment also provides a possible implementation scheme:

[0045] AFE module 21 is mounted on AFE circuit board 20. AFE circuit board 20 and main board 10 are spliced ​​together to form a single circuit board. AFE module 21 is electrically connected to single-axis inverter module 12 and dual-axis inverter module 11 through copper busbars and cables.

[0046] In one possible application scenario, the assembled AFE circuit board 20 and the motherboard 10 are as follows: Figure 3 As shown. Among them, Figure 3 The portion to the left of the dashed line represents the AFE circuit board 20 and the AFE module 21 mounted on the AFE circuit board 20. Figure 3 The part to the right of the dotted line is the mainboard 10, and the single-axis inverter module 12 and dual-axis inverter module 11 set on the mainboard 10. The AFE circuit board 20 is spliced ​​with the mainboard 10, and they are electrically connected to each other through copper busbars and cables. The whole unit adopts an integrated design, which further reduces the overall size.

[0047] On the other hand, as can be seen from the above embodiments, the three-axis drive frequency converter provided in this application achieves frequency conversion control function by integrating three originally separate frequency converters onto a single circuit board, thereby simplifying circuit size and wiring complexity. However, compared to the original separate design, this integrated approach may make certain compromises in data communication between each frequency converter and the outside world; that is, it is more difficult for the integrated frequency converters to interact with external devices. To solve this problem, this embodiment also provides a further implementation scheme, such as... Figure 2 As shown, the above-mentioned three-axis drive frequency converter also includes: a communication module, which is connected to the communication terminal on the AFE circuit board 20 and the main board 10;

[0048] The communication terminal on the motherboard 10 is a common terminal for communication between the single-axis frequency converter module 12 and the dual-axis frequency converter module 11 and external devices; the communication terminal on the AFE circuit board 20 is a port for communication between the AFE module 21 and external devices.

[0049] In other words, in this embodiment, by adding a communication module, the integrated single-axis inverter module 12, dual-axis inverter module 11 and AFE module 21 can communicate with external devices. This allows the module to receive control commands from external devices or return the electrical parameters it has collected to external devices, which is beneficial to the operation of the air conditioning equipment.

[0050] It is particularly important to note that, based on the integrated design requirements of the single-axis inverter module 12 and the dual-axis inverter module 11 in the above embodiments, the single-axis inverter module 12 and the dual-axis inverter module 11 in this embodiment also share a communication port on the motherboard 10 as a port for connecting to the communication module. Since there is only one AFE module 21 on the AFE circuit board 20, only one communication port needs to be reserved for communication with external devices, and no additional configuration is required. The specifications and standards of the aforementioned communication ports are determined by the communication protocol on which the communication module communicates with the motherboard 10 and the AFE circuit board 20, and this embodiment does not impose any restrictions on this. However, further considering that in the actual application scenarios of air conditioning equipment, the three-axis drive inverter provided in this application usually needs to operate in an environment with strong electromagnetic interference, the communication protocol used between the aforementioned communication module and the motherboard 10 and the AFE circuit board 20 can specifically be RS-485 (a communication protocol). RS-485 has strong resistance to electromagnetic interference and lightning interference, which can ensure communication quality in the harsh working environment where air conditioning equipment is used.

[0051] Furthermore, regarding how the communication module communicates with external devices, one or more communication methods, such as wired or wireless, can be used. This embodiment does not impose any restrictions on this; the appropriate settings can be made according to the communication needs of the external devices. However, for air conditioning equipment, strong electromagnetic interference exists in its working environment, and wireless communication would compromise communication quality or be prohibitively expensive. Therefore, wired communication is generally used. Further, in one possible embodiment, such as... Figure 2 As shown, the communication module described above specifically includes:

[0052] Analog input (AI), digital input (DI), analog output (AO), and external communication terminal (communication) for communicating with external devices, as well as internal communication terminal (RS485) for communicating with single-axis frequency converter module 12, dual-axis frequency converter module 11, and AFE module 21.

[0053] In other words, in this embodiment, the communication module and external devices can be wired through multiple communication ports, including digital and analog signal input and output, to meet the different communication requirements of different external devices. It can also establish communication connections with multiple external devices at the same time, making the establishment of communication connections more flexible and convenient.

[0054] Furthermore, as can be seen from the aforementioned embodiments of the mainboard 10 and AFE circuit board 20, the three-axis drive frequency converter provided in this application can be implemented in a highly integrated integrated board form, for example... Figure 3 The integrated board shown is composed of a main board 10 and an AFE circuit board 20.

[0055] Accordingly, this embodiment also provides a specific implementation scheme for the communication module provided in the previous embodiment:

[0056] The communication module is a programmable logic controller (PLC) communication module and is mounted on the PLC communication board 30. The PLC communication board 30 is positioned above the AFE circuit board 20 and is fixedly connected to the AFE circuit board 20.

[0057] It should be noted that the term "above" in this embodiment refers to the direction in the physical space where the AFE circuit board 20 with the side containing the electrical components is placed vertically upwards.

[0058] Specifically, in the actual production design of the integrated board composed of the motherboard 10 and the AFE circuit board 20, it was found that: due to the presence of electrical components such as inductors on the motherboard 10, when the motherboard 10 is placed flat on a horizontal surface, its vertical height is significantly greater than that of the AFE circuit board 20. And the integrated board is obtained by splicing the motherboard 10 and the AFE circuit board 20, as... Figure 3 As shown, this splicing relationship is generally horizontal. Therefore, in actual production design, unless a non-standard shell is used as the outer casing of the integrated board, there will be some wasted space above the AFE circuit board 20. To address this, this embodiment implements the aforementioned communication module using a PLC, and the corresponding circuit board containing the communication module is the PLC communication board 30. The communication module circuit structure implemented by the PLC is simple and compact, well-suited to the underutilized space above the AFE circuit board 20. Therefore, this embodiment implements the communication module using a PLC and places the PLC communication board 30 above the AFE circuit board 20. The main board 10, AFE circuit board 20, and PLC communication board 30 together form an integrated board. The resulting integrated board has a relatively regular shape, and even using a regular-shaped shell as the protective casing, it still has a high space utilization rate, which meets the implementation design requirements of the electrical control box in current air conditioning equipment.

[0059] Furthermore, in the above embodiment, the PLC communication board 30 is fixed to the AFE circuit board 20 to achieve an integrated design. Regarding the fixed connection between the PLC communication board 30 and the AFE circuit board 20, this embodiment also provides a possible implementation scheme:

[0060] The PLC communication board 30 and the AFE circuit board 20 are fixedly connected by spacers. The length of the spacers is greater than the maximum vertical height of the electrical components mounted on the AFE circuit board 20, but less than the maximum vertical height of the electrical components mounted on the main board 10.

[0061] Similar to the previous embodiment, the maximum vertical height of the electrical components on the AFE circuit board 20 and main board 10 mentioned in this embodiment is also the height when the AFE circuit board 20 / main board 10 is placed flat on a horizontal surface with the side containing the electrical components facing vertically upwards. In this embodiment, the length of the spacer column must not be less than the maximum height of the electrical components on the AFE circuit board 20 to prevent the PLC communication board 30, which is positioned above the AFE circuit board 20, from squeezing the electrical components on the AFE circuit board 20. The length of the spacer column must not be greater than the maximum height of the electrical components on the main board 10 to ensure that when the PLC communication board 30 is positioned above the AFE circuit board 20, the space not fully utilized due to the height difference between the main board 10 and the AFE circuit board 20 at the maximum height of the electrical components can be effectively utilized, thereby further improving the integration level of the three-axis drive inverter and reducing the overall size.

[0062] In summary, this application discloses a three-axis drive frequency converter. By integrating three separate frequency converters from a traditional air conditioning unit into a single three-axis drive frequency converter, the operation of three motor devices can be simultaneously controlled via a single circuit board. This significantly reduces the circuit size of the frequency conversion control section in the air conditioning unit and also reduces the wiring harness between frequency converters, thus helping to reduce the overall material cost of the air conditioning unit. Furthermore, in several possible embodiments, this application also integrates an AFE module 21 and a communication module into the three-axis drive frequency converter, which are used to implement harmonic mitigation of the external power input and communication connection with external devices, respectively. The AFE module 21 and the communication module are integrated with the main board, further reducing the overall size through splicing and fixing methods, and making greater use of the limited space in the water-cooled air conditioning control box.

[0063] In the above embodiments, a three-axis drive frequency converter has been described in detail. This application also provides an embodiment corresponding to an air conditioner control box. An air conditioner control box device includes: a three-axis drive frequency converter as described in any of the above embodiments.

[0064] Since the embodiments of the air conditioner control box and the three-axis drive inverter correspond to each other, please refer to the description of the embodiments of the three-axis drive inverter for the embodiment of the air conditioner control box, which will not be repeated here.

[0065] The air conditioning control box in this embodiment uses the three-axis drive inverter provided in the above embodiment, which can further reduce the overall circuit volume while ensuring the frequency conversion control of the compressor, fan and water pump. As a result, the air conditioning control box provided in this embodiment is smaller and more advantageous in size compared with the traditional control box that houses three separate inverter designs.

[0066] Similarly, this application also provides an embodiment of an air conditioning device, which includes: an air conditioning control box as described in the previous embodiment, and a compressor, a fan, and a water pump connected to the air conditioning control box.

[0067] Since the embodiments of the air conditioning equipment section correspond to the embodiments of the three-axis drive inverter section, the embodiments of the air conditioning equipment section can also refer to the description of the embodiments of the three-axis drive inverter section, which will not be repeated here.

[0068] As can be seen from the above, the air conditioning equipment in this embodiment adopts the three-axis drive inverter provided in the above embodiment, which can meet the energy-saving requirements of the whole machine in actual application without significantly increasing the size and number of wiring harnesses of the air conditioning equipment due to the circuit of the inverter control part, thereby ensuring the ease of implementation and installation of this air conditioning equipment on the end user side.

[0069] The above provides a detailed description of a three-axis drive frequency converter, an air conditioning control box, and an air conditioning device provided by this utility model. The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section. It should be noted that those skilled in the art can make various improvements and modifications to this utility model without departing from its principles, and these improvements and modifications also fall within the protection scope of this utility model.

[0070] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A three-axis drive frequency converter, characterized by Comprise: A dual-shaft variable frequency module and a single-shaft variable frequency module; Wherein, the single-shaft variable frequency module and the dual-shaft variable frequency module are integrated on the same mainboard, and share the power input end of the mainboard to access the power supply; the single-shaft variable frequency module is used for variable frequency control of one of the compressor, the fan and the water pump, and the dual-shaft variable frequency module is used for variable frequency control of the other two of the compressor, the fan and the water pump.

2. The three-axis drive frequency inverter according to claim 1, characterized by The single-shaft variable frequency module is used for variable frequency control of the compressor, and the dual-shaft variable frequency module is used for variable frequency control of the fan and the water pump.

3. The three-axis drive frequency inverter according to claim 1, characterized by Also comprise: AFE module; Wherein, the AFE module is used for rectification and voltage conversion of the three-phase power input from the outside, and provides two-way DC power input to supply the single-shaft variable frequency module and the dual-shaft variable frequency module.

4. The three-axis drive frequency inverter according to claim 3, characterized by The AFE module is arranged on the AFE circuit board, and the AFE circuit board is spliced with the mainboard into one circuit board, and the AFE module is electrically connected with the single-shaft variable frequency module and the dual-shaft variable frequency module through copper bars and cables.

5. The three-axis drive frequency inverter according to claim 4, characterized by Also comprise: Communication module, the communication module is connected with the communication end on the AFE circuit board and the mainboard; Wherein, the communication end on the mainboard is a common end for the single-shaft variable frequency module and the dual-shaft variable frequency module to communicate with external equipment; the communication end on the AFE circuit board is a port for the AFE module to communicate with external equipment.

6. The three-axis drive frequency inverter of claim 5, wherein, The communication module comprises: an analog input end, a digital input end, an analog output end and an external communication end for communicating with external equipment, and an internal communication end for communicating with the single-shaft variable frequency module, the dual-shaft variable frequency module and the AFE module.

7. The three-axis drive frequency inverter of claim 5, wherein, The communication module is a PLC communication module, and is arranged on a PLC communication board; The PLC communication board is arranged above the AFE circuit board and is fixedly connected with the AFE circuit board.

8. The three-axis drive frequency inverter of claim 7, wherein, The PLC communication board and the AFE circuit board are fixedly connected through a spacing column; Wherein, the length of the spacing column is greater than the maximum height of the electrical elements arranged on the AFE circuit board in the vertical direction, and less than the maximum height of the electrical elements arranged on the mainboard in the vertical direction.

9. An air conditioner electric control box, characterized by, Comprise: The three-shaft drive frequency converter and the electric control box shell according to any one of claims 1 to 8.

10. An air conditioning apparatus characterized by comprising: Comprise: The air conditioner electric control box according to claim 9, and the compressor, the fan and the water pump connected with the air conditioner electric control box.

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