Control method and control device of air conditioning system, and air conditioning system

Abstract

The application relates to the air conditioning technical field and provides an air conditioner system control method, a control device and an air conditioner system.The air conditioner system comprises a direct-current bus, a four-quadrant rectifier, a wind power system, a photovoltaic system, an energy storage system and an air conditioner connected with the direct-current bus, and the four-quadrant rectifier is connected with a commercial power grid; the control method comprises the following steps: obtaining a direct-current bus voltage; obtaining energy storage information of the energy storage system; and controlling the energy storage system and the four-quadrant rectifier according to the direct-current bus voltage and the energy storage information of the energy storage system, so that the direct-current bus runs to a target preset voltage.The application can realize the balance between power supply and demand of the entire air conditioner system, guarantee the stable reliability of system operation, realize the preferential local consumption of photovoltaic wind power, reduce the loss in the AC-DC energy conversion process, improve the energy utilization rate, realize the centralized and unified management and control of the entire system, improve the linkage degree between each part of the system, and reduce the complexity of system control.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and in particular to a control method, control device and air conditioning system for an air conditioning system. Background Technology

[0002] In related technologies, by applying new energy sources to air conditioning systems, energy conservation and environmental protection can be achieved. For example, combining photovoltaic systems, wind power systems, energy storage systems, and the mains power grid with air conditioning can form a multi-new energy power supply air conditioning system. In this system, the photovoltaic system, wind power system, energy storage system, and air conditioning are all centered on the mains power grid, each acting as a subsystem of the mains power grid, and energy is transferred to each other in the form of alternating current through an AC bus.

[0003] Currently, the air conditioning system has the following problems: (1) Since the photovoltaic system generates electricity in the form of DC, it needs to be converted into AC through an inverter and transmitted to the grid before it can be used by loads such as air conditioners. Losses are easily generated during the inverter and grid transmission process. Moreover, due to the instability, intermittency and volatility of photovoltaics, it is not suitable for direct grid connection; (2) The energy storage system stores electricity in the form of DC. It needs to be converted into AC through a bidirectional energy storage inverter to realize the storage and release of electricity. Losses are also generated during the inverter process; (3) Although the wind power system generates AC, in order to maximize the utilization of wind power generation, Wind turbines cannot be directly connected to the grid. The common practice is to first rectify the AC power generated by the wind turbine into DC power, and then convert it into AC power through the wind turbine inverter for grid connection and transmission before use. Similar to photovoltaics, wind power itself also has the disadvantages of instability, intermittency and fluctuation, which make it unsuitable for grid connection. In addition, losses are also generated in the process of the wind turbine inverter converting DC power into AC power. (4) Air conditioners are large power consumers. They need to rectify the AC power of the grid into DC power and then invert it for use. Losses are also generated in the rectification process. (5) Each part of the system is independent of each other and needs to be controlled independently. The control is complicated and the linkage is low. Summary of the Invention

[0004] This invention provides a control method, control device, and air conditioning system for an air conditioning system. It can achieve a balance between power supply and demand for the entire air conditioning system, ensure the stability and reliability of system operation, and enable the priority local consumption of photovoltaic and wind power. It can effectively reduce losses in the process of multiple AC / DC energy conversion, improve energy utilization, and achieve centralized and unified management and control of the entire system, improve the linkage between various parts of the system, and reduce the complexity of system control.

[0005] This invention provides a control method for an air conditioning system, the air conditioning system comprising: a DC bus and a four-quadrant rectifier, a wind power system, a photovoltaic system, an energy storage system, and an air conditioner connected to the DC bus, wherein the four-quadrant rectifier is connected to the mains power grid; the control method comprises:

[0006] Obtain the DC bus voltage;

[0007] Obtain the energy storage information of the energy storage system;

[0008] Based on the DC bus voltage and the energy storage information of the energy storage system, the energy storage system and the four-quadrant rectifier are controlled to make the DC bus operate at the target preset voltage.

[0009] According to a control method for an air conditioning system provided by the present invention, the energy storage information includes: remaining power; the steps of controlling the energy storage system and the four-quadrant rectifier based on the DC bus voltage and the energy storage information of the energy storage system specifically include:

[0010] When the DC bus voltage is less than the target preset voltage, when the DC bus voltage reaches the first preset voltage, if the remaining power of the energy storage system is greater than the preset power, the energy storage system is controlled to discharge to the DC bus, so that the DC bus starts to operate with the first preset voltage as the initial voltage.

[0011] Once the DC bus voltage reaches the target preset voltage, the energy storage system is in a shut-off state.

[0012] According to a control method for an air conditioning system provided by the present invention, the step of determining that the DC bus voltage reaches the target preset voltage and the energy storage system is in a closed state specifically includes:

[0013] During the discharge process, if the DC bus voltage reaches the target preset voltage and the remaining power of the energy storage system is greater than the preset power, the energy storage system is controlled to shut down.

[0014] According to a control method for an air conditioning system provided by the present invention, the step of determining that the DC bus voltage reaches the target preset voltage and the energy storage system is in a closed state further includes:

[0015] During the discharge process, if the DC bus voltage does not reach the target preset voltage and the DC bus voltage reaches the second preset voltage, the four-quadrant rectifier is adjusted to control the mains power grid to supply power to the DC bus, so that the DC bus starts to operate with the second preset voltage as the initial voltage.

[0016] Once the DC bus voltage reaches the target preset voltage, the four-quadrant rectifier is controlled to shut down.

[0017] According to a control method for an air conditioning system provided by the present invention, the energy storage information further includes: remaining capacity; the step of controlling the energy storage system and the four-quadrant rectifier based on the DC bus voltage and the energy storage information of the energy storage system specifically includes:

[0018] When the DC bus voltage is greater than the target preset voltage, when the DC bus voltage reaches the third preset voltage, if the remaining capacity of the energy storage system is greater than the preset capacity, the energy storage system is controlled to draw power from the DC bus for charging, so that the DC bus starts to operate with the third preset voltage as the initial voltage.

[0019] Once the DC bus voltage reaches the target preset voltage, the energy storage system is in a shut-off state.

[0020] According to a control method for an air conditioning system provided by the present invention, the step of determining that the DC bus voltage reaches the target preset voltage and the energy storage system is in a closed state specifically includes:

[0021] During the charging process, if the DC bus voltage reaches the target preset voltage and the remaining capacity of the energy storage system is greater than the preset capacity, the energy storage system is controlled to shut down.

[0022] According to a control method for an air conditioning system provided by the present invention, the step of determining that the DC bus voltage reaches the target preset voltage and the energy storage system is in a closed state further includes:

[0023] During the charging process, if the DC bus voltage does not reach the target preset voltage and the DC bus voltage reaches the fourth preset voltage, the four-quadrant rectifier is adjusted to control the DC bus to feed power to the mains grid, so that the DC bus starts to operate with the fourth preset voltage as the initial voltage.

[0024] Once the DC bus voltage reaches the target preset voltage, the four-quadrant rectifier is controlled to shut down.

[0025] A control method for an air conditioning system provided by the present invention further includes:

[0026] The wind power system and the photovoltaic system are controlled to always operate at the maximum power output allowed by the MPPT.

[0027] The present invention also provides a control device for an air conditioning system, the air conditioning system comprising: a DC bus and a four-quadrant rectifier, a wind power system, a photovoltaic system, an energy storage system, and an air conditioner connected to the DC bus, wherein the four-quadrant rectifier is connected to the mains power grid; the control device comprises:

[0028] The first acquisition module is used to acquire the DC bus voltage;

[0029] The second acquisition module is used to acquire the energy storage information of the energy storage system;

[0030] The control module is used to control the energy storage system and the four-quadrant rectifier according to the DC bus voltage and the energy storage information of the energy storage system, so as to make the DC bus operate at the target preset voltage.

[0031] The present invention also provides an air conditioning system, including the control device of the air conditioning system described above, or, when performing control, employing the control method of the air conditioning system described above.

[0032] The air conditioning system control method, control device, and air conditioning system provided by this invention integrate a wind power system, a photovoltaic system, an energy storage system, a mains power grid, and an air conditioner to form a wind-solar-storage-grid air conditioning system, achieving energy conservation and environmental protection. Furthermore, by directly connecting the wind power system, photovoltaic system, and energy storage system to the air conditioner via a DC bus, instead of directly connecting them to the AC mains power grid, no AC / DC conversion is required between the four systems. All connections are DC, allowing for direct local utilization and consumption without grid connection, reducing losses from AC / DC conversion and long-distance power transmission, and effectively improving energy efficiency. Moreover, by employing a four-quadrant rectifier, bidirectional energy flow between the mains power grid and the DC bus can be controlled, thereby achieving active control of the DC bus voltage. By acquiring the DC bus voltage and energy storage information of the energy storage system, and controlling the energy storage system and the four-quadrant rectifier based on this information, the DC bus can be operated to the target preset voltage, thus balancing the power supply and demand of the entire system and ensuring its stable and normal operation. Therefore, this invention can enable priority local consumption of photovoltaic and wind power, effectively reduce losses in the process of multiple AC / DC energy conversion, improve energy utilization, and achieve centralized and unified management and control of the entire system, improve the linkage between various parts of the system, and reduce the complexity of system control. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in this invention or related technologies, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the air conditioning system provided by the present invention;

[0035] Figure 2 This is one of the flowcharts illustrating the control method of the air conditioning system provided by the present invention;

[0036] Figure 3 This is the second flowchart illustrating the control method of the air conditioning system provided by the present invention;

[0037] Figure 4 This is the third flowchart illustrating the control method for the air conditioning system provided by the present invention;

[0038] Figure 5 This is the fourth flowchart illustrating the control method for the air conditioning system provided by the present invention;

[0039] Figure 6 This is the fifth flowchart illustrating the control method of the air conditioning system provided by the present invention;

[0040] Figure 7 This is a schematic diagram of the structure of the control device for the air conditioning system provided by the present invention.

[0041] Figure label:

[0042] 1: Municipal power grid; 2: Four-quadrant rectifier; 3: Wind power system; 4: Photovoltaic system;

[0043] 5: Energy storage system; 6: Air conditioning; 7: AC bus; 8: DC bus;

[0044] 9: First acquisition module; 10: Second acquisition module; 11: Control module. Detailed Implementation

[0045] 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.

[0046] In the description of the embodiments of the present invention, it should be noted that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0047] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0048] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0049] The following is combined Figures 1-7 The present invention describes a control method, a control device, and an air conditioning system.

[0050] According to one embodiment of the present invention, referring to Figure 1 As shown, this invention provides an air conditioning system, which mainly includes: a mains power grid 1, a four-quadrant rectifier 2, a wind power system 3, a photovoltaic system 4, an energy storage system 5, and an air conditioner 6. This invention can be understood as a wind-solar-storage-grid-air-power station type new energy air conditioning system that combines the above components. By utilizing new energy sources such as photovoltaics and wind power for power supply, it can achieve the purpose of energy conservation and environmental protection.

[0051] In this design, the mains power grid 1 is connected to the input side of the four-quadrant rectifier 2 via AC bus 7, and the output side of the four-quadrant rectifier 2 is connected to the DC bus 8. The wind power system 3, photovoltaic system 4, energy storage system 5, and air conditioning system 6 are directly connected to the DC bus 8, not directly to the mains power grid 1. This design eliminates the need for AC / DC conversion between the four systems, allowing them to be fully DC connected. Wind and photovoltaic energy can be preferentially consumed locally, without directly feeding power to the mains power grid 1, but instead used to power the local air conditioning system 6 load. This eliminates the need for grid connection, reduces losses from AC / DC conversion and long-distance transmission, and effectively improves energy utilization.

[0052] The four-quadrant rectifier 2 can control the bidirectional flow of energy between the mains power grid 1 and the DC bus 8, thereby actively controlling the DC bus voltage to achieve the target preset voltage, thus balancing the power supply and demand of the entire system and ensuring the normal and stable operation of the entire system.

[0053] It is understood that the present invention does not impose any particular restrictions on the specific type of the four-quadrant rectifier 2, as long as it can perform the functions mentioned in the present invention.

[0054] The wind power system 3 and the photovoltaic system 4 are mainly used to directly supply power to loads such as air conditioner 6 via DC bus 8, and have MPPT (maximum power point tracking) function, which can always operate at the maximum power output allowed by MPPT. During operation, there is no need to adjust its output power, so as to realize the most efficient use of wind and photovoltaic energy and reduce the start-up time of air conditioner 6.

[0055] The energy storage system 5 can achieve bidirectional energy flow with the DC bus 8, realizing the charging and discharging process, thereby regulating the DC bus voltage to reach the target preset voltage, thus balancing the power supply and demand of the entire system and ensuring the normal and stable operation of the entire system.

[0056] According to one embodiment of the present invention, referring to Figure 2 As shown, the present invention provides a control method for the above-mentioned air conditioning system, the control method mainly including the following steps:

[0057] S100, Obtain DC bus voltage;

[0058] S200: Obtain energy storage information from energy storage system 5;

[0059] S300: Based on the DC bus voltage and the energy storage information of the energy storage system 5, control the energy storage system 5 and the four-quadrant rectifier 2 to make the DC bus 8 operate at the target preset voltage.

[0060] For example, if the DC bus voltage is less than the target preset voltage, but the remaining charge of the energy storage system 5 is greater than the preset charge, it indicates that the discharge capacity of the energy storage system 5 is sufficient. At this time, the energy storage system 5 is controlled to discharge directly to the DC bus 8 to increase the voltage. Furthermore, if the remaining charge of the energy storage system 5 is less than the preset charge during the continuous discharge process, it indicates that the discharge capacity of the energy storage system 5 is insufficient. If the DC bus voltage still does not reach the target preset voltage, the four-quadrant rectifier 2 can be adjusted to allow the energy of the mains grid 1 to flow unidirectionally to the DC bus 8 to supply power, thereby increasing the voltage until the target preset voltage is reached.

[0061] Similarly, when the DC bus voltage is greater than the target preset voltage, if the remaining capacity of the energy storage system 5 is greater than the preset capacity, it indicates that the charging capacity of the energy storage system 5 is sufficient. At this time, the energy storage system 5 is controlled to directly draw power from the DC bus 8 for charging to reduce the voltage. At the same time, the energy storage system 5 can be used for the next discharge through charging, improving the energy recycling rate. Furthermore, if the remaining capacity of the energy storage system 5 is less than the preset capacity during the continuous charging process, it indicates that the energy storage system 5 is close to being fully charged and the charging capacity is insufficient. At this time, if the DC bus voltage still has not reached the target preset voltage, the four-quadrant rectifier 2 can be adjusted to make the energy of the DC bus 8 flow unidirectionally to the mains power grid 1 for power supply to reduce the voltage until the target preset voltage is reached.

[0062] It should be noted that in order to achieve a balance between power supply and demand in the entire system, it is necessary to control the power supply of wind power system 3 and photovoltaic system 4, as well as the charging and discharging process of energy storage system 5. During the control process, it is necessary to monitor multiple control parameters in real time, such as the power supply of wind power system 3 and photovoltaic system 4, and the energy storage information of energy storage system 5. The control process is relatively complex.

[0063] Therefore, this embodiment of the invention controls the four-quadrant rectifier 2 and the energy storage system 5 by detecting the DC bus voltage and the energy storage information of the energy storage system. There is no need to control the wind power system 3 and the photovoltaic system 4. The number of controlled objects in the whole process is relatively small. Furthermore, the judgment of charging and discharging of the energy storage system 5 and the judgment of controllable rectification or grid connection of the four-quadrant rectifier 2 do not require external commands. They can be automatically judged based on the level of the DC bus voltage. This allows for rapid adjustment of the DC bus voltage, improves control efficiency, and reduces the complexity of the entire air conditioning system control.

[0064] The air conditioning system control method provided in this embodiment of the invention can achieve a balance between power supply and demand for the entire air conditioning system, ensure the stability and reliability of system operation, and enable the priority local consumption of photovoltaic and wind power energy, effectively reduce losses in the process of multiple AC / DC energy conversion, improve energy utilization, and achieve centralized and unified management and control of the entire system, improve the degree of linkage between various parts of the system, and reduce the complexity of system control.

[0065] According to one embodiment of the present invention, referring to Figure 3 As shown, the energy storage information of energy storage system 5 includes: remaining power; the steps for controlling energy storage system 5 and four-quadrant rectifier 2 based on DC bus voltage and energy storage information of energy storage system 5 specifically include:

[0066] S301. When the DC bus voltage is less than the target preset voltage, when the DC bus voltage reaches the first preset voltage, if the remaining power of the energy storage system 5 is greater than the preset power, control the energy storage system 5 to discharge to the DC bus 8, so that the DC bus starts to operate with the first preset voltage as the initial voltage.

[0067] S302. Determine that the DC bus voltage has reached the target preset voltage, and the energy storage system 5 is in the off state.

[0068] Specifically, during the operation of the air conditioning system, when the total power supply of the wind power system 3 and the photovoltaic system 4 is less than the power consumption of the air conditioner 6, the DC bus voltage is lower than the target preset voltage. At this time, when the DC bus voltage drops to the first preset voltage, the discharge capacity of the energy storage system 5 is first judged. If the remaining power of the energy storage system 5 is greater than the preset power, it means that the discharge capacity of the energy storage system 5 is sufficient. At this time, the energy storage system 5 can be controlled to discharge directly to the DC bus 8. During the discharge process, the DC bus 8 starts to rise with the first preset voltage as the initial voltage until the target preset voltage is reached. This process does not require the control of the wind power system 3 and the photovoltaic system 4, thereby reducing the complexity of the control of the entire air conditioning system.

[0069] Unlike the above embodiments, by controlling the discharge amount of the energy storage system 5, the DC bus is kept running at a first preset voltage for a certain period of time, thereby improving the stability and reliability of the air conditioner 6. In this process, the total power supply of the wind power system 3 and the photovoltaic system 4 can be detected in real time. When the total power supply shows an upward trend and exceeds the power consumption of the air conditioner 6, the DC bus voltage may also reach the target preset voltage. At this time, the discharge amount of the energy storage system 5 can be reduced accordingly, and the energy storage system 5 can be shut down in advance.

[0070] According to one embodiment of the present invention, referring to Figure 4 As shown, the steps for determining that the DC bus voltage has reached the target preset voltage and the energy storage system 5 is in a shut-off state specifically include:

[0071] S3021. During the discharge process, if the DC bus voltage reaches the target preset voltage and the remaining power of the energy storage system 5 is greater than the preset power, control the energy storage system 5 to shut down.

[0072] Specifically, if the DC bus voltage reaches the target preset voltage during the continuous discharge process of the energy storage system 5, but the remaining power of the energy storage system 5 is still greater than the preset power, the energy storage system 5 should be shut down to avoid over-supply, so as to ensure the power supply and demand balance of the entire air conditioning system and improve the stability of the air conditioning system.

[0073] According to one embodiment of the present invention, referring to Figure 4 As shown, the step of determining that the DC bus voltage has reached the target preset voltage and the energy storage system 5 is in the off state also includes:

[0074] S3022. During the discharge process, if the DC bus voltage does not reach the target preset voltage and the DC bus voltage reaches the second preset voltage, adjust the four-quadrant rectifier 2 to control the mains power grid 1 to supply power to the DC bus 8, so that the DC bus 8 starts to operate with the second preset voltage as the initial voltage.

[0075] S3023. Determine that the DC bus voltage has reached the target preset voltage, and control the four-quadrant rectifier 2 to shut down.

[0076] Specifically, if the DC bus 8 still does not reach the target preset voltage during the continuous discharge process of the energy storage system 5, it indicates that the discharge capacity of the energy storage system 5 is insufficient. The energy storage system 5 can shut down automatically or be shut down under control. When the DC bus voltage drops to the second preset voltage, the four-quadrant rectifier 2 is adjusted to perform controllable rectification, so that the energy of the mains power grid 1 flows unidirectionally to the DC bus 8 to supply power to it, so that the DC bus 8 starts to operate with the second preset voltage as the initial voltage until the target preset voltage is reached, and the four-quadrant rectifier 2 is controlled to shut down.

[0077] Unlike the above embodiments, by controlling the four-quadrant rectifier 2, the DC bus 8 is kept running at the second preset voltage for a certain period of time, thereby improving the stability and reliability of the air conditioner 6. In this process, the total power supply of the wind power system 3 and the photovoltaic system 4 can be detected in real time. When the total power supply shows an upward trend and is greater than the power consumption of the air conditioner, the DC bus 8 may be raised to the first preset voltage and run for a period of time. During this operation, when the total power supply shows an upward trend again and is greater than the power consumption of the air conditioner, the target preset voltage is reached, thereby realizing the phased buffer voltage boost.

[0078] According to one embodiment of the present invention, referring to Figure 5As shown, the energy storage information also includes: remaining capacity; the steps for controlling the energy storage system 5 and the four-quadrant rectifier 2 based on the DC bus voltage and the energy storage information of the energy storage system 5 specifically include:

[0079] S303. When the DC bus voltage is greater than the target preset voltage, when the DC bus voltage reaches the third preset voltage, if the remaining capacity of the energy storage system 5 is greater than the preset capacity, control the energy storage system 5 to draw power from the DC bus 8 for charging, so that the DC bus 8 starts to operate with the third preset voltage as the initial voltage.

[0080] S304. Once the DC bus voltage reaches the target preset voltage, the energy storage system 5 is in the off state.

[0081] Specifically, during the operation of the air conditioning system, when the total power supply of the wind power system 3 and the photovoltaic system 4 is greater than the power consumption of the air conditioner 6, the DC bus voltage will be greater than the target preset voltage. At this time, when the DC bus voltage rises to the third preset voltage, the charging capacity of the energy storage system 5 is first judged. If the remaining capacity of the energy storage system 5 is greater than the preset capacity, it means that the charging capacity of the energy storage system 5 is sufficient. At this time, the energy storage system 5 can be controlled to directly draw power from the DC bus 8 for charging and storage. During the charging process, the DC bus 8 starts to reduce the voltage with the third preset voltage as the initial voltage until the target preset voltage is reached. This process does not require the control of the wind power system 3 and the photovoltaic system 4, thereby reducing the complexity of the control of the entire air conditioning system.

[0082] Unlike the above embodiments, by controlling the charging amount of the energy storage system 5, the DC bus 8 is kept running at a third preset voltage for a certain period of time, thereby improving the stability and reliability of the air conditioner 6. In this process, the total power supply of the wind power system 3 and the photovoltaic system 4 is monitored in real time. When the total power supply shows a downward trend and is less than the power consumption of the air conditioner 6, the DC bus voltage may also reach the target preset voltage. At this time, the charging amount of the energy storage system 5 can be reduced accordingly, and the energy storage system 5 can be shut down in advance.

[0083] According to one embodiment of the present invention, referring to Figure 6 As shown, the steps for determining that the DC bus voltage has reached the target preset voltage and the energy storage system 5 is in a shut-off state specifically include:

[0084] S3041. During the charging process, if the DC bus voltage reaches the target preset voltage and the remaining capacity of the energy storage system 5 is greater than the preset capacity, control the energy storage system 5 to shut down.

[0085] Specifically, if the DC bus voltage reaches the target preset voltage during the continuous charging process of the energy storage system 5, but the remaining capacity of the energy storage system 5 is still greater than the preset capacity, the energy storage system 5 should be shut down to avoid excessive power consumption, so as to ensure the balance of power supply and demand of the entire system and improve the stability of the air conditioning system.

[0086] According to one embodiment of the present invention, referring to Figure 6 As shown, the step of determining that the DC bus voltage has reached the target preset voltage and the energy storage system 5 is in the off state also includes:

[0087] S3042. During the charging process, if the DC bus voltage does not reach the target preset voltage and the DC bus voltage reaches the fourth preset voltage, adjust the four-quadrant rectifier 2 to control the DC bus 8 to feed power to the mains grid 1, so that the DC bus 8 starts to operate with the fourth preset voltage as the initial voltage.

[0088] S3043. Determine that the DC bus voltage has reached the target preset voltage, and control the four-quadrant rectifier 2 to shut down.

[0089] Specifically, if the DC bus 8 does not reach the target preset voltage during the continuous charging process of the energy storage system 5, it indicates that the energy storage system 5 has insufficient power extraction capacity. The energy storage system 5 can shut down automatically or be shut down under control. When the DC bus voltage rises to the fourth preset voltage, the four-quadrant rectifier 2 is adjusted to perform inverter grid connection, so that the energy of the DC bus 8 flows unidirectionally to the mains power grid 1. The DC bus 8 starts to operate at a reduced voltage with the fourth preset voltage as the initial voltage until the target preset voltage is reached, and the four-quadrant rectifier 2 is controlled to shut down.

[0090] Unlike the above embodiments, by controlling the four-quadrant rectifier 2, the DC bus 8 is kept running at the fourth preset voltage for a certain period of time, thereby improving the stability and reliability of the air conditioner 6. In this process, the total power supply of the wind power system 3 and the photovoltaic system 4 can be detected in real time. When the total power supply shows a downward trend and is less than the power consumption of the air conditioner 6, the DC bus voltage may be reduced to the third preset voltage for a period of time. During this operation, when the total power supply shows a downward trend again and is less than the power consumption of the air conditioner 6, the target preset voltage is reached, thereby achieving phased buffer voltage reduction.

[0091] According to one embodiment of the present invention, the control method of the air conditioning system of the present invention further includes: controlling the wind power system 3 and the photovoltaic system 4 to always operate at the maximum power output allowed by MPPT, without adjusting the output power of the wind power system 3 and the photovoltaic system 4 throughout the process, so as to maximize the utilization rate of photovoltaic and wind power.

[0092] For example, when the air conditioner 6 is started, the wind power system 3 and the photovoltaic system 4 are always operating at the maximum power output allowed by the MPPT, which can directly supply power to the air conditioner 6 and reduce the start-up time of the air conditioner 6. If the power generated by the wind power system 3 and the photovoltaic system 4 is greater than the power consumption of the air conditioner 6, the excess power can be transmitted to the mains power grid 1 for grid-connected power generation.

[0093] When the air conditioner 6 stops running, the wind power system 3 and the photovoltaic system 4 are always operating at the maximum power output allowed by the MPPT, and the generated electricity can be transmitted to the mains power grid 1 for grid-connected power generation.

[0094] The control device for the air conditioning system provided by the present invention is described below. The control device for the air conditioning system described below can be referred to in correspondence with the control method for the air conditioning system described above.

[0095] According to one embodiment of the present invention, referring to Figure 1 and Figure 7 As shown, the present invention also provides a control device for an air conditioning system, the air conditioning system including: a DC bus 8 and a four-quadrant rectifier 2, a wind power system 3, a photovoltaic system 4, an energy storage system 5 and an air conditioner 6 connected to the DC bus 8, and the four-quadrant rectifier 2 is connected to the mains power grid 1.

[0096] The control device mainly includes a first acquisition module 9, a second acquisition module 10, and a control module 11. The first acquisition module 9 acquires the DC bus voltage; the second acquisition module 10 acquires the energy storage information of the energy storage system 5; and the control module 11 controls the energy storage system 5 and the four-quadrant rectifier 2 based on the DC bus voltage and the energy storage information of the energy storage system 5, so that the DC bus 8 operates at the target preset voltage. The specific control process of the control device is described above and will not be repeated here.

[0097] The control device for the air conditioning system provided in this embodiment of the invention, through the first acquisition module 9, the second acquisition module 10 and the control module 11, can realize the balance of power supply and demand of the entire air conditioning system, ensure the stable and reliable operation of the system, and enable the priority local consumption of photovoltaic and wind power energy, effectively reduce the loss in the process of multiple AC-DC energy conversion, improve energy utilization, and realize centralized and unified management and control of the entire system, improve the linkage between various parts of the system, and reduce the complexity of system control.

[0098] On the other hand, the present invention also provides an air conditioning system, including the control device of the air conditioning system of the above embodiments, or, when performing control, employing the control method of the air conditioning system of the above embodiments.

[0099] Since the air conditioning system of this embodiment includes the control device or control method of the air conditioning system of the above embodiment, it has all the technical effects of the control device or control method of the air conditioning system of the above embodiment, which will not be elaborated here.

[0100] 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 control method of an air conditioning system, characterized by, The air conditioning system comprises a direct current bus, a four-quadrant rectifier, a wind power system, a photovoltaic system, an energy storage system and an air conditioner connected with the direct current bus, and the four-quadrant rectifier is connected with a power grid; the control method comprises: obtaining a direct current bus voltage; obtaining energy storage information of the energy storage system; controlling the energy storage system and the four-quadrant rectifier according to the direct current bus voltage and the energy storage information of the energy storage system, so that the direct current bus operates to a target preset voltage; the energy storage information comprises a residual power; the step of controlling the energy storage system and the four-quadrant rectifier according to the direct current bus voltage and the energy storage information of the energy storage system specifically comprises: in the case that the direct current bus voltage is less than the target preset voltage, when the direct current bus voltage reaches a first preset voltage, if the residual power of the energy storage system is greater than a preset power, discharging the energy storage system to the direct current bus is controlled, so that the direct current bus starts to operate with the first preset voltage as an initial voltage; determining that the direct current bus voltage reaches the target preset voltage and the energy storage system is in a closed state; the step of determining that the direct current bus voltage reaches the target preset voltage and the energy storage system is in a closed state specifically comprises: in the process of discharging, if the direct current bus voltage reaches the target preset voltage and the residual power of the energy storage system is greater than the preset power, the energy storage system is controlled to be closed; the energy storage information further comprises a residual capacity; the step of controlling the energy storage system and the four-quadrant rectifier according to the direct current bus voltage and the energy storage information of the energy storage system specifically comprises: in the case that the direct current bus voltage is greater than the target preset voltage, when the direct current bus voltage reaches a third preset voltage, if the residual capacity of the energy storage system is greater than a preset capacity, taking power from the direct current bus to charge the energy storage system is controlled, so that the direct current bus starts to operate with the third preset voltage as an initial voltage; determining that the direct current bus voltage reaches the target preset voltage and the energy storage system is in a closed state; the step of determining that the direct current bus voltage reaches the target preset voltage and the energy storage system is in a closed state specifically comprises: in the process of charging, if the direct current bus voltage reaches the target preset voltage and the residual capacity of the energy storage system is greater than the preset capacity, the energy storage system is controlled to be closed.

2. The control method of the air conditioning system according to claim 1, characterized by, the step of determining that the direct current bus voltage reaches the target preset voltage and the energy storage system is in a closed state further comprises: in the process of discharging, if the direct current bus voltage does not reach the target preset voltage and the direct current bus voltage reaches a second preset voltage, the four-quadrant rectifier is adjusted to control the power grid to supply power to the direct current bus, so that the direct current bus starts to operate with the second preset voltage as an initial voltage; determining that the direct current bus voltage reaches the target preset voltage and controlling the four-quadrant rectifier to be closed.

3. The control method of the air conditioning system according to claim 1, characterized by, the step of determining that the direct current bus voltage reaches the target preset voltage and the energy storage system is in a closed state further comprises: In the process of charging, if the DC bus voltage does not reach the target preset voltage, and the DC bus voltage reaches a fourth preset voltage, the four-quadrant rectifier is adjusted to control the DC bus to feed the power grid, so that the DC bus starts running with the fourth preset voltage as the initial voltage; It is determined that the DC bus voltage reaches the target preset voltage, and the four-quadrant rectifier is controlled to be closed.

4. The control method of an air conditioning system according to any one of claims 1 to 3, characterized by, Also includes: The wind power system and the photovoltaic system are controlled to always run at the maximum power output allowed by MPPT.

5. A control device of an air conditioning system, characterized by comprising: The control method of the air conditioning system according to any one of claims 1 to 4, the air conditioning system comprising: a DC bus, a four-quadrant rectifier, a wind power system, a photovoltaic system, an energy storage system and an air conditioner connected to the DC bus, and the four-quadrant rectifier being connected to a power grid; the control device comprising: A first acquisition module for acquiring a DC bus voltage; A second acquisition module for acquiring energy storage information of the energy storage system; A control module for controlling the energy storage system and the four-quadrant rectifier according to the DC bus voltage and the energy storage information of the energy storage system, so that the DC bus runs to a target preset voltage.

6. An air conditioning system characterized by comprising: The control device of the air conditioning system according to claim 5, or the control method of the air conditioning system according to any one of claims 1 to 4 is used when the control is performed.

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