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

Abstract

The invention relates to the technical field of air conditioners, and provides a control method and device of an air conditioning system and the air conditioning system.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, and the four-quadrant rectifier, the wind power system, the photovoltaic system, the energy storage system and the air conditioner are connected with the direct-current bus; the control method comprises the following steps: acquiring DC bus voltage; acquiring energy storage information of an energy storage system; and 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 operates to the target preset voltage. The power supply and demand balance of the whole air conditioning system can be realized, the stability and reliability of system operation are ensured, the preferential local consumption of photovoltaic wind power can be realized, the loss in the alternating current and direct current energy conversion process is reduced, the energy utilization rate is improved, and the centralized and unified management and control of the whole system can be realized; the linkage degree of all parts of the system is improved, and the complexity of system control is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and in particular to a control method and a control device of an air conditioning system and an air conditioning system. Background Art

[0002] In the related technologies, energy conservation and environmental protection can be achieved by applying new energy to air-conditioning systems. For example, photovoltaic systems, wind power systems, energy storage systems, mains power grids and air conditioners are combined to form a multi-renewable energy powered air-conditioning system, in which the photovoltaic system, wind power system, energy storage system and air conditioners are all centered on the mains power grid, and each serves as a subsystem of the mains power grid, and realizes energy transmission in the form of alternating current through the AC bus.

[0003] At present, the air conditioning system has the following problems: (1) Since the photovoltaic system generates electricity in the form of direct current, it needs to be converted into alternating current through an inverter and connected to the grid before it can be provided to loads such as air conditioners. Losses are easily generated during the inversion and grid-connected transmission process, and due to the instability, intermittency and volatility of photovoltaics themselves, it is not suitable for direct grid connection; (2) The energy storage system stores electricity in the form of direct current, and needs to use a bidirectional energy storage inverter to realize the conversion between direct current and alternating current and connect to the grid to realize the storage and release of electricity. Losses are also generated during the inversion process; (3) Although the wind power system generates alternating current, in order to maximize the utilization of wind power generation , wind turbines cannot be directly connected to the grid. The current 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 a wind turbine inverter and connect it to the grid for transmission and reuse. Similar to the characteristics of photovoltaic power, wind power itself also has disadvantages such as instability, intermittency and volatility that are not suitable for grid connection. In addition, losses are also generated in the process of the wind turbine inverter converting DC power into AC power; (4) As a large power consumer, air conditioners need to rectify the AC power of the municipal power 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, which makes the control complex and the degree of linkage low. Summary of the invention

[0004] The present invention provides a control method, a control device and an air-conditioning system, which can achieve a balance between electricity supply and demand of the entire air-conditioning system, ensure the stable and reliable operation of the system, and can realize the priority on-site consumption of photovoltaic and wind power, effectively reduce the loss in multiple AC and DC energy conversion processes, improve energy utilization, and realize centralized and unified control of the entire system, improve the degree of linkage between various parts of the system, and reduce the complexity of system control.

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

[0006] Get the DC bus voltage;

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

[0008] According to 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 run to a target preset voltage.

[0009] According to a control method of an air conditioning system provided by the present invention, the energy storage information includes: remaining power; and the steps of 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 specifically include:

[0010] In the case where the DC bus voltage is less than the target preset voltage, when the DC bus voltage reaches a 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] It is determined that the DC bus voltage reaches the target preset voltage and the energy storage system is in a closed 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 be 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 a 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] Determine that the DC bus voltage reaches the target preset voltage, and control the four-quadrant rectifier to turn off.

[0017] According to a control method of an air conditioning system provided by the present invention, the energy storage information further includes: remaining capacity; and the steps of 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 specifically include:

[0018] In the case where the DC bus voltage is greater than the target preset voltage, when the DC bus voltage reaches a 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] It is determined that the DC bus voltage reaches the target preset voltage and the energy storage system is in a closed 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 be 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 a fourth preset voltage, the four-quadrant rectifier is adjusted to control the DC bus to feed power to the commercial power grid, so that the DC bus starts to operate with the fourth preset voltage as the initial voltage;

[0024] Determine that the DC bus voltage reaches the target preset voltage, and control the four-quadrant rectifier to turn off.

[0025] A control method for an air conditioning system according to 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 connected to the DC bus, a wind power system, a photovoltaic system, an energy storage system and an air conditioner, and the four-quadrant rectifier is connected to a commercial power grid; the control device comprises:

[0028] A first acquisition module, used for acquiring a DC bus voltage;

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

[0030] A 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 that the DC bus runs to a target preset voltage.

[0031] The present invention further provides an air-conditioning system, comprising the control device of the air-conditioning system, or adopting the control method of the air-conditioning system when executing control.

[0032] The control method, control device and air-conditioning system provided by the present invention can achieve the purpose of energy saving and environmental protection by integrating the wind power system, photovoltaic system, energy storage system, mains power grid and air-conditioning to form a wind-solar-storage-grid-air-station-type new energy air-conditioning system; and by directly connecting the wind power system, photovoltaic system and energy storage system to the air-conditioning via a DC bus instead of directly connecting them to the AC mains power grid, that is, no AC-DC conversion is required between the wind power system, photovoltaic system, energy storage system and air-conditioning, and all are connected in DC, which can be directly utilized and consumed on site without grid connection, thereby reducing the losses of AC-DC conversion and long-distance power transmission and effectively improving energy utilization; and by adopting a four-quadrant rectifier, energy can be controlled to flow bidirectionally between the mains power grid and the DC bus, thereby achieving the purpose of actively controlling the DC bus voltage; by obtaining the DC bus voltage and the energy storage information of the energy storage system, and 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, the DC bus can be operated to the target preset voltage, thereby balancing the power supply and demand of the entire system and ensuring the stable and normal operation of the system. Therefore, the present invention can realize the priority on-site consumption of photovoltaic and wind power, effectively reduce the loss in multiple AC and DC energy conversion processes, improve energy utilization, and realize centralized and unified control of the entire system, improve the degree of linkage between various parts of the system, and reduce the complexity of system control. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the present invention or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

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

[0035] Figure 2 It is one of the flow charts of the control method of the air conditioning system provided by the present invention;

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

[0037] Figure 4 This is a third flow chart of the control method of the air conditioning system provided by the present invention;

[0038] Figure 5 This is a fourth flow chart of the control method of the air conditioning system provided by the present invention;

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

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

[0041] Reference numerals:

[0042] 1: Mains 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 DESCRIPTION

[0045] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

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

[0047] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0048] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0049] Combine the following Figure 1-Figure 7 The control method, control device and air conditioning system of the present invention are described.

[0050] According to one embodiment of the present invention, referring to Figure 1 As shown, the present invention provides an air conditioning system, which mainly includes: a city 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. The system of the present invention can be understood as a wind-solar-storage-grid-air-station-type new energy air conditioning system after combining the above parts, which can achieve the purpose of energy saving and environmental protection by using new energy such as photovoltaics and wind power for power supply.

[0051] Among them, the mains power grid 1 is connected to the input side of the four-quadrant rectifier 2 via the AC bus 7, the output side of the four-quadrant rectifier 2 is connected to the DC bus 8, and the wind power system 3, the photovoltaic system 4, the energy storage system 5 and the air conditioner 6 are directly connected to the DC bus 8 respectively, and are not directly connected to the mains power grid 1. With this design, there is no need for AC-DC conversion between the wind power system 3, the photovoltaic system 4, the energy storage system 5 and the air conditioner 6, and all are connected by DC. Energy such as wind power and photovoltaic power can be directly consumed locally, that is, it is not directly fed to the mains power grid 1, but is used to supply power to the local air conditioner 6 load, without the need for grid connection, reducing the loss of AC-DC conversion and long-distance power transmission, and effectively improving energy utilization.

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

[0053] It is understandable that the present invention does not impose any particular limitation on the specific type of the four-quadrant rectifier 2 as long as it can play the role 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 the air conditioner 6 via the DC bus 8, and have an MPPT (maximum power point tracking) function, and can always operate at the maximum power output allowed by the MPPT. There is no need to adjust its output power during operation, thereby achieving the most efficient use of wind power and photovoltaic energy, and reducing the startup time of the air conditioner 6.

[0055] The energy storage system 5 can realize bidirectional energy flow with the DC bus 8, realize the charging and discharging process, so as to adjust the DC bus voltage to reach the target preset voltage, thereby 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 air conditioning system, and the control method mainly includes the steps of:

[0057] S100, obtaining DC bus voltage;

[0058] S200, obtaining energy storage information of the energy storage system 5;

[0059] S300 , according to 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 run to a target preset voltage.

[0060] For example, when the DC bus voltage is less than the target preset voltage, 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 is controlled to discharge directly to the DC bus 8 to increase the voltage; and, during the continuous discharge of the energy storage system 5, if the remaining power of the energy storage system 5 is less than the preset power, it means that the discharge capacity of the energy storage system 5 is insufficient. At this time, if the DC bus voltage still does not reach the target preset voltage, the four-quadrant rectifier 2 can be adjusted to make the energy of the mains power grid 1 flow unidirectionally to the DC bus 8 for power supply to increase 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 means 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 to improve the energy recycling rate; and during the continuous charging process of the energy storage system 5, if the remaining capacity of the energy storage system 5 is less than the preset capacity, it means 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 does not reach 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 grid 1 for feeding to reduce the voltage until the target preset voltage is reached.

[0062] It should be noted that in the relevant technology, in order to balance the supply and demand of electricity in the entire system, it is necessary to control the power supply of the wind power system 3 and the photovoltaic system 4 and the charging and discharging of the energy storage system 5. During the control process, it is necessary to detect multiple control parameters such as the power supply of the wind power system 3 and the photovoltaic system 4 and the energy storage information of the energy storage system 5 in real time, and the control process is relatively complicated.

[0063] To this end, the embodiment of the present 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, without the need to control the wind power system 3 and the photovoltaic system 4. The control objects of the whole process are relatively few, and the charging and discharging judgment of the energy storage system 5 and the controllable rectification or inverter grid-connected judgment of the four-quadrant rectifier 2 do not require external instructions. It is only necessary to automatically judge according to the level of the DC bus voltage, so that the DC bus voltage can be quickly adjusted, the control efficiency is improved, and the complexity of the control of the whole air-conditioning system is reduced.

[0064] The control method of the air-conditioning system provided in the embodiment of the present invention can achieve a balance between electricity supply and demand of the entire air-conditioning system, ensure the stable and reliable operation of the system, and can realize the priority on-site consumption of photovoltaic and wind power energy, effectively reduce the loss in multiple AC and DC energy conversion processes, improve energy utilization, and realize centralized and unified 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 the energy storage system 5 includes: the remaining power; according to the DC bus voltage and the energy storage information of the energy storage system 5, the steps of controlling the energy storage system 5 and the four-quadrant rectifier 2 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 reaches the target preset voltage and the energy storage system 5 is in a closed 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, resulting in the DC bus voltage being less 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, and during the discharge process, the DC bus 8 starts to boost operation 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] Different from the above-mentioned embodiment, the discharge amount of the energy storage system 5 is controlled to keep the DC bus running at the first preset voltage for a certain period of time, thereby improving the stability and reliability of the operation of the air conditioner 6. In this process, the total power supply power of the wind power system 3 and the photovoltaic system 4 can be detected in real time. When the total power supply power shows an upward trend and is greater than 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 step of determining that the DC bus voltage reaches the target preset voltage and the energy storage system 5 is in the off state specifically includes:

[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, the energy storage system 5 is controlled to be shut down.

[0072] Specifically, during the continuous discharge of the energy storage system 5, if the DC bus voltage reaches the target preset voltage, but at this time, the remaining power of the energy storage system 5 is still greater than the preset power, in order to avoid overpowering, the energy storage system 5 should be shut down to ensure the balance of power supply and demand 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 reaches 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 reaches the target preset voltage, and control the four-quadrant rectifier 2 to turn off.

[0076] Specifically, during the continuous discharge of the energy storage system 5, if the DC bus 8 still does not reach the target preset voltage, it means that the discharge capacity of the energy storage system 5 is insufficient at this time, and the energy storage system 5 can be shut down by itself or 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 municipal 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 be shut down.

[0077] Different from the above-mentioned embodiment, the four-quadrant rectifier 2 is controlled to keep the DC bus 8 running at the second preset voltage for a certain period of time, thereby improving the stability and reliability of the operation of the air conditioner 6, and 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 also be increased 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 a staged buffer boost.

[0078] According to one embodiment of the present invention, referring to Figure 5As shown, the energy storage information also includes: remaining capacity; according to the DC bus voltage and the energy storage information of the energy storage system 5, the steps of controlling the energy storage system 5 and the four-quadrant rectifier 2 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: Determine that the DC bus voltage reaches the target preset voltage and the energy storage system 5 is in a closed 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, resulting in the DC bus voltage being 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 step down 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] Different from the above-mentioned embodiment, the DC bus 8 is kept running at the third preset voltage for a certain period of time by controlling the charging amount of the energy storage system 5, thereby improving the stability and reliability of the operation of the air conditioner 6, and in this process, the total power supply power of the wind power system 3 and the photovoltaic system 4 is detected in real time. When the total power supply power 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 step of determining that the DC bus voltage reaches the target preset voltage and the energy storage system 5 is in the off state specifically includes:

[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, the energy storage system 5 is controlled to be shut down.

[0085] Specifically, during the continuous charging process of the energy storage system 5, if the DC bus voltage reaches the target preset voltage, but at this time, the remaining capacity of the energy storage system 5 is still greater than the preset capacity, in order to avoid excessive power consumption, the energy storage system 5 should be shut down 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 reaches 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 reaches the target preset voltage, and control the four-quadrant rectifier 2 to turn off.

[0089] Specifically, during the continuous charging process of the energy storage system 5, if the DC bus 8 still does not reach the target preset voltage, it means that the power supply capacity of the energy storage system 5 is insufficient at this time, and the energy storage system 5 can be shut down automatically or 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, and the DC bus 8 starts to step down 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 be shut down.

[0090] Different from the above-mentioned embodiment, the four-quadrant rectifier 2 is controlled to keep the DC bus 8 running at the fourth preset voltage for a certain period of time, thereby improving the stability and reliability of the operation of the air conditioner 6, and 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 power shows a downward trend and is less than the power consumption of the air conditioner 6, the DC bus voltage may also be reduced to the third preset voltage for a period of time. During this operation, when the total power supply power shows a downward trend again and is less than the power consumption of the air conditioner 6, the target preset voltage is reached, thereby realizing staged buffer voltage reduction.

[0091] According to one embodiment of the present invention, the control method of the air-conditioning system of the present invention also includes: controlling the wind power system 3 and the photovoltaic system 4 to always operate at the maximum power output allowed by MPPT, and the output power of the wind power system 3 and the photovoltaic system 4 does not need to be adjusted during the entire process, so as to maximize the utilization rate of photovoltaic and wind power.

[0092] For example, when the air conditioner 6 starts running, the wind power system 3 and the photovoltaic system 4 are controlled to always run at the maximum power output allowed by MPPT, so that power can be directly supplied to the air conditioner 6 to reduce the start-up time of the air conditioner 6. If the electric energy 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 electric energy can be transmitted to the municipal 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 controlled to always run at the maximum power output allowed by the MPPT, and the generated electric energy can be transmitted to the commercial power grid 1 for grid-connected power generation.

[0094] The control device of the air-conditioning system provided by the present invention is described below. The control device of the air-conditioning system described below and the control method of the air-conditioning system described above can be referred to each other.

[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 comprising: a DC bus 8 and a four-quadrant rectifier 2 connected to the DC bus 8, a wind power system 3, a photovoltaic system 4, an energy storage system 5 and an air conditioner 6, 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 is used to acquire the DC bus voltage; the second acquisition module 10 is used to acquire the energy storage information of the energy storage system 5; the control module 11 is used to control the energy storage system 5 and the four-quadrant rectifier 2 according to the DC bus voltage and the energy storage information of the energy storage system 5, so that the DC bus 8 runs to the target preset voltage. For the specific control process of the control device, please refer to the above, which will not be repeated here.

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

[0098] On the other hand, the present invention further provides an air-conditioning system, including the control device of the air-conditioning system of the above embodiment, or adopting the control method of the air-conditioning system of the above embodiment when performing control.

[0099] Since the air-conditioning system of the embodiment of the present invention 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 described in detail here.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control method for an air conditioning system, characterized in that: The air conditioning system comprises: a DC bus and a four-quadrant rectifier connected to the DC bus, a wind power system, a photovoltaic system, an energy storage system and an air conditioner, and the four-quadrant rectifier is connected to a commercial power grid; the control method comprises: Get the DC bus voltage; Acquiring energy storage information of the energy storage system; According to 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 run to a target preset voltage.

2. The control method of the air conditioning system according to claim 1, characterized in that: The energy storage information includes: remaining power; and the steps of 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 specifically include: In the case where the DC bus voltage is less than the target preset voltage, when the DC bus voltage reaches a 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; It is determined that the DC bus voltage reaches the target preset voltage and the energy storage system is in a closed state.

3. The control method of the air conditioning system according to claim 2, characterized in that: 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: 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 be shut down.

4. The control method of the air conditioning system according to claim 3, characterized in that: 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: During the discharge process, if the DC bus voltage does not reach the target preset voltage and the DC bus voltage reaches a 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; Determine that the DC bus voltage reaches the target preset voltage, and control the four-quadrant rectifier to turn off.

5. The control method of the air conditioning system according to claim 1, characterized in that: The energy storage information also includes: remaining capacity; and the steps of 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, specifically including: In the case where the DC bus voltage is greater than the target preset voltage, when the DC bus voltage reaches a 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; It is determined that the DC bus voltage reaches the target preset voltage and the energy storage system is in a closed state.

6. The control method of the air conditioning system according to claim 5, characterized in that: 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: 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 be shut down.

7. The control method of the air conditioning system according to claim 6, characterized in that: 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: During the charging process, 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 power to the commercial power grid, so that the DC bus starts to operate with the fourth preset voltage as the initial voltage; Determine that the DC bus voltage reaches the target preset voltage, and control the four-quadrant rectifier to turn off.

8. The control method of the air conditioning system according to any one of claims 1 to 7, characterized in that: Also includes: The wind power system and the photovoltaic system are controlled to always operate at the maximum power output allowed by the MPPT.

9. A control device for an air conditioning system, characterized in that: The air conditioning system comprises: a DC bus and a four-quadrant rectifier connected to the DC bus, a wind power system, a photovoltaic system, an energy storage system and an air conditioner, and the four-quadrant rectifier is connected to the mains power grid; the control device comprises: A first acquisition module, used for acquiring a DC bus voltage; A second acquisition module, used to acquire energy storage information of the energy storage system; A 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 that the DC bus runs to a target preset voltage.

10. An air conditioning system, characterized in that: The invention comprises the control device of the air conditioning system as claimed in claim 9, or when performing control, adopts the control method of the air conditioning system as claimed in any one of claims 1 to 8.

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