Photovoltaic air conditioning system and control method and control device thereof

Abstract

The invention discloses a photovoltaic air conditioning system and a control method and device thereof. The technical problem that an existing photovoltaic air conditioning system is unstable in operation is solved. The control method comprises the steps that the real-time output power of a photovoltaic module in the photovoltaic air conditioner system and the real-time required power of an air conditioner load are obtained; when the photovoltaic air conditioning system is in an off-grid state and the real-time output power of the photovoltaic module is smaller than the real-time required power of the air conditioning load, the first control process and the second control process are executed in sequence; the first control process comprises the steps that a first target rotating speed is determined according to the real-time direct-current bus voltage of the photovoltaic air conditioner system, and an air conditioner compressor is controlled to operate according to the first target rotating speed; and the second control process comprises the steps that after the first control process is finished, a second target rotating speed is determined according to the real-time output power of the photovoltaic module and the real-time required power of the air conditioner load, and the air conditioner compressor is controlled to operate according to the second target rotating speed.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy-saving air treatment, and in particular, relates to a photovoltaic air conditioning system and a control method and a control device thereof. Background Art

[0002] As an energy-saving air-conditioning system, photovoltaic air-conditioning system has been widely used in many fields such as production and life with the increasingly urgent demand for energy conservation and emission reduction and the continuous maturity of photovoltaic technology.

[0003] In order to meet the user's demand for air conditioning and make full use of solar energy, when the power grid is normally powered, the photovoltaic air conditioning system usually operates in a hybrid power mode, with the power grid and photovoltaic modules simultaneously powering the air conditioning system. After the power grid is cut off, the photovoltaic air conditioning system is off-grid, and the photovoltaic modules provide power for the air conditioning system. When the power provided by the photovoltaic modules cannot meet the power required by the air conditioning system, the air conditioning system often loses step or shuts down, causing the air conditioning system to operate unstably and affecting the use of the air conditioning system. Summary of the invention

[0004] The object of the present invention is to provide a control method and a control device for a photovoltaic air-conditioning system, so as to improve the operation stability of the photovoltaic air-conditioning system.

[0005] In order to achieve the above-mentioned purpose of the invention, the control method of the photovoltaic air conditioning system provided by the present invention is implemented by adopting the following technical scheme: A control method for a photovoltaic air conditioning system, comprising: Obtain the real-time output power of the photovoltaic components in the photovoltaic air-conditioning system and the real-time required power of the air-conditioning load; When the photovoltaic air-conditioning system is in an off-grid state and the real-time output power of the photovoltaic module is less than the real-time required power of the air-conditioning load, the following first control process and second control process are sequentially executed; The first control process includes: determining a first target speed according to a real-time DC bus voltage of the photovoltaic air conditioning system, and controlling the operation of the air conditioning compressor according to the first target speed so that the operation of the air conditioning follows the change of the DC bus voltage; The second control process includes: after the first control process is completed, determining a second target speed according to the real-time output power of the photovoltaic component and the real-time required power of the air-conditioning load, and controlling the operation of the air-conditioning compressor according to the second target speed so that the operation of the air-conditioning follows the changes in power supply and demand.

[0006] In some embodiments of the present application, determining the first target speed according to the real-time DC bus voltage of the photovoltaic air conditioning system specifically includes: Obtaining a difference between a given DC bus voltage and the real-time DC bus voltage as a bus voltage deviation; Processing the bus voltage deviation to obtain a first compensation speed; Obtaining a difference between a given speed and the first compensation speed as a first compensated speed; The first compensated rotational speed is determined as the first target rotational speed.

[0007] In some embodiments of the present application, controlling the operation of the air-conditioning compressor according to the first target speed specifically includes: Processing the first compensation speed to obtain a first speed adjustment step; Obtaining a real-time speed of the air-conditioning compressor and comparing it with the first target speed; When the real-time speed is less than or equal to the first target speed, the real-time speed is used as the base speed, the first speed adjustment step length is used as the speed adjustment step length, the real-time speed is increased to obtain a first actual speed, and the air-conditioning compressor is controlled to operate at the first actual speed until the first actual speed increases to the first target speed; When the real-time speed is greater than the first target speed, the real-time speed is used as the base speed, and the first speed adjustment step is used as the speed adjustment step to reduce the real-time speed to obtain the second actual speed, and the air-conditioning compressor is controlled to operate at the second actual speed until the second actual speed is reduced to the first target speed.

[0008] In some embodiments of the present application, processing the first compensation speed to obtain a first speed adjustment step size specifically includes: Performing a proportional operation or a proportional integral operation on the first compensation speed to obtain an operation result; The calculation result is limited to obtain the first speed adjustment step.

[0009] In some embodiments of the present application, determining the second target speed according to the real-time output power of the photovoltaic assembly and the real-time required power of the air conditioning load specifically includes: Obtaining a difference between the real-time required power of the air-conditioning load and the real-time output power of the photovoltaic module as a power deviation; Processing the power deviation to obtain a second compensation rotation speed; Obtaining a difference between a given speed and the second compensation speed as a second compensated speed; The second compensated rotational speed is determined as the second target rotational speed.

[0010] In some embodiments of the present application, controlling the operation of the air-conditioning compressor according to the second target speed specifically includes: Processing the second compensation speed to obtain a second speed adjustment step length; Obtaining a real-time speed of the air-conditioning compressor, and comparing it with the second target speed; When the real-time speed is less than or equal to the second target speed, taking the real-time speed as the base speed and the second speed adjustment step as the speed adjustment step, increasing the real-time speed to obtain a third actual speed, and controlling the operation of the air-conditioning compressor with the third actual speed until the third actual speed increases to the second target speed; When the real-time speed is greater than the second target speed, the real-time speed is used as the base speed, and the second speed adjustment step is used as the speed adjustment step to reduce the real-time speed to obtain a fourth actual speed, and the air-conditioning compressor is controlled to operate at the fourth actual speed until the fourth actual speed is reduced to the second target speed.

[0011] In some embodiments of the present application, processing the second compensation speed to obtain a second speed adjustment step size specifically includes: Performing a proportional operation or a proportional integral operation on the second compensation speed to obtain an operation result; The calculation result is limited to obtain the second speed adjustment step.

[0012] In some embodiments of the present application, the speed setting is determined by the following process: Obtain the real-time temperature and humidity of the indoor environment where the photovoltaic air-conditioning system is located and the real-time fan speed of the indoor unit in the photovoltaic air-conditioning system; Determine a real-time effective temperature index according to the real-time temperature, the real-time humidity and the real-time fan speed; Obtaining a difference between a given effective temperature index and the real-time effective temperature index as an effective temperature index deviation; The effective temperature deviation is processed to obtain the rotational speed setting.

[0013] In order to achieve the above-mentioned purpose of the invention, the control device of the photovoltaic air conditioning system provided by the present invention adopts the following technical solutions: A control device for a photovoltaic air conditioning system, comprising: A real-time output power acquisition unit of a photovoltaic module, used to acquire the real-time output power of a photovoltaic module in a photovoltaic air-conditioning system; The real-time power demand acquisition unit of the air-conditioning load is used to acquire the real-time power demand of the air-conditioning load in the photovoltaic air-conditioning system; A control unit, configured to sequentially execute the following first control process and second control process when the photovoltaic air conditioning system is in an off-grid state and the real-time output power of the photovoltaic module is less than the real-time required power of the air conditioning load; The first control process includes: determining a first target speed according to a real-time DC bus voltage of the photovoltaic air conditioning system, and controlling the operation of the air conditioning compressor according to the first target speed so that the operation of the air conditioning follows the change of the DC bus voltage; The second control process includes: after the first control process is completed, determining a second target speed according to the real-time output power of the photovoltaic component and the real-time required power of the air-conditioning load, and controlling the operation of the air-conditioning compressor according to the second target speed so that the operation of the air-conditioning follows the changes in power supply and demand.

[0014] Another object of the present invention is to provide a photovoltaic air-conditioning system, comprising a photovoltaic component and an air-conditioner, wherein the photovoltaic air-conditioning system also comprises the control device of the photovoltaic air-conditioning system mentioned above.

[0015] Compared with the prior art, the advantages and positive effects of the present invention are: The photovoltaic air-conditioning system and its control method and control device provided by the present invention are as follows: when the photovoltaic air-conditioning system is in an off-grid state where the power grid is cut off, the photovoltaic air-conditioning system is powered by a photovoltaic module. When the real-time output power of the photovoltaic module is less than the real-time power demand of the air-conditioning load, the first target speed is first determined according to the real-time DC bus voltage of the photovoltaic air-conditioning system, and the air-conditioning compressor is controlled to operate at the first target speed, so that the operation of the air-conditioning follows the change of the DC bus voltage. Since the DC bus voltage changes greatly after the photovoltaic power grid is cut off, the target speed of the air-conditioning compressor is first adjusted according to the DC bus voltage, which can quickly respond to the power supply state and ensure the stable operation of the air-conditioning; then, the second target speed is determined according to the real-time output power of the photovoltaic module and the real-time power demand of the air-conditioning load, and the air-conditioning compressor is controlled to operate at the second target speed, so that the operation of the air-conditioning follows the change of power supply and demand, and the air-conditioning compressor speed is prevented from being adjusted too quickly and overshooting occurs, thereby affecting the stable operation of the air-conditioning; thus, when the photovoltaic air-conditioning system is in an off-grid state, two different control processes are used to adjust the compressor speed in stages, which can improve the continuous operation stability of the photovoltaic air-conditioning system and ensure the use of the air-conditioning system.

[0016] After reading the specific embodiments of the present invention in conjunction with the accompanying drawings, other features and advantages of the present invention will become more clear. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, a brief introduction will be given below to the drawings required for use in the embodiments. 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 creative work.

[0018] Figure 1 It is a flow chart of a first embodiment of a control method for a photovoltaic air conditioning system of the present invention; Figure 2 A flow chart of a second embodiment of a control method for a photovoltaic air conditioning system of the present invention; Figure 3 It is a flow chart of a third embodiment of the control method of the photovoltaic air conditioning system of the present invention; Figure 4 is a flow chart of a fourth embodiment of a control method for a photovoltaic air conditioning system of the present invention; Figure 5 is a flow chart of a fifth embodiment of a control method for a photovoltaic air conditioning system of the present invention; Figure 6 It is a structural schematic diagram of an embodiment of a control device of a photovoltaic air conditioning system of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0020] It should be noted that the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0021] Figure 1 The flowchart of the first embodiment of the control method of the photovoltaic air conditioning system of the present invention is shown. In this embodiment, the photovoltaic air conditioning system includes a photovoltaic module and an air conditioner, and the air conditioner can be powered by a power grid and / or a photovoltaic module. The control method of this embodiment includes: S11: Determine that the photovoltaic air-conditioning system is in an off-grid state and the real-time output power of the photovoltaic components is less than the real-time required power of the air-conditioning load.

[0022] In this embodiment, it is necessary to obtain the real-time output power of the photovoltaic components in the photovoltaic air-conditioning system and the real-time required power of the air-conditioning load.

[0023] The real-time output power of the photovoltaic module is the output power of the photovoltaic module obtained in real time according to the set sampling period, and the real-time demand power of the air-conditioning load is the demand power of the air-conditioning load obtained in real time according to the set sampling period. The method for obtaining the real-time output power of the photovoltaic module can be implemented by using relevant technologies, and this embodiment does not limit the specific acquisition method. In some embodiments, the real-time output power of the photovoltaic module is obtained according to the real-time output voltage and real-time output current of the photovoltaic module. In some other embodiments, the real-time output power of the photovoltaic module is obtained according to the prediction of the photovoltaic module power generation prediction model. The method for obtaining the real-time demand power of the air-conditioning load can be implemented by using relevant technologies, and this embodiment does not limit the specific acquisition method. In some embodiments, the real-time demand power of the air-conditioning load is obtained according to the prediction of the air-conditioning load prediction model. In some other embodiments, the real-time demand power of the air-conditioning load is calculated based on the real-time temperature and set temperature of the indoor environment where the air-conditioning is located.

[0024] In this embodiment, the grid state is also detected in real time. When the grid is powered off, it is determined that the photovoltaic air conditioning system is in an off-grid state. In the off-grid state, the photovoltaic air conditioning system is powered solely by the photovoltaic module. In addition, in the off-grid state, the obtained real-time output power of the photovoltaic module is compared with the real-time required power of the air conditioning load to determine whether the real-time output power of the photovoltaic module is less than the real-time required power of the air conditioning load.

[0025] If the real-time output power of the photovoltaic module is less than the real-time required power of the air conditioning load, it means that the power provided by the photovoltaic module cannot meet the power required by the air conditioning system. To ensure the use of the air conditioning, it is necessary to control the air conditioning to reduce the actual operating power. In addition, to ensure the stability of the air conditioning when it is running at reduced power, this embodiment uses the following two different control processes S12 and S13 to control the air conditioning.

[0026] S12: Under the condition that the photovoltaic air-conditioning system is in an off-grid state and the real-time output power of the photovoltaic components is less than the real-time required power of the air-conditioning load, the first control process is first executed, and the first target speed is determined according to the real-time DC bus voltage of the photovoltaic air-conditioning system. The operation of the air-conditioning compressor is controlled according to the first target speed, so that the operation of the air-conditioning changes with the change of the DC bus voltage.

[0027] The real-time DC bus voltage is the DC bus voltage of the photovoltaic air conditioning system acquired in real time according to a set sampling period, and the acquisition method thereof can be implemented by using relevant technologies, and this embodiment does not limit the specific acquisition method.

[0028] This embodiment does not limit the specific implementation method of determining the first target speed according to the real-time DC bus voltage of the photovoltaic air-conditioning system. All implementation methods that can make the operation of the air conditioner change with the change of the DC bus voltage to maintain stable operation of the air conditioner fall within the protection scope of the present invention.

[0029] S13: After the first control process is completed, the second control process is executed to determine the second target speed according to the real-time output power of the photovoltaic module and the real-time required power of the air-conditioning load, and the operation of the air-conditioning compressor is controlled according to the second target speed, so that the operation of the air-conditioning changes with the change of power supply and demand.

[0030] This embodiment does not limit the specific implementation method of determining the second target speed based on the real-time output power of the photovoltaic module and the real-time required power of the air-conditioning load. All implementation methods that can make the operation of the air conditioner change with the changes in power supply and demand to maintain stable operation of the air conditioner fall within the protection scope of the present invention.

[0031] The photovoltaic air-conditioning system is controlled by the method of the above embodiment. When the photovoltaic module is in an off-grid state, when the real-time output power of the photovoltaic module is less than the real-time power demand of the air-conditioning load, the first target speed is first determined according to the real-time DC bus voltage of the photovoltaic air-conditioning system, and the air-conditioning compressor is controlled to operate at the first target speed, so that the operation of the air-conditioning follows the change of the DC bus voltage. Since the DC bus voltage changes greatly after the photovoltaic power grid is powered off, the target speed of the air-conditioning compressor is first adjusted according to the DC bus voltage, which can quickly respond to the power supply state and ensure the stable operation of the air-conditioning; then, the second target speed is determined according to the real-time output power of the photovoltaic module and the real-time power demand of the air-conditioning load, and the air-conditioning compressor is controlled to operate at the second target speed, so that the operation of the air-conditioning follows the change of power supply and demand, and avoids the air-conditioning compressor speed adjustment too fast to cause overshoot and affect the stable operation of the air-conditioning; thus, when the photovoltaic air-conditioning system is in an off-grid state, two different control processes are used to adjust the compressor speed in stages, which can improve the continuous operation stability of the photovoltaic air-conditioning system and ensure the use of the air-conditioning system.

[0032] In some other embodiments, in an off-grid state, if the real-time output power of the photovoltaic module is not less than the real-time required power of the air-conditioning load, it indicates that the power provided by the photovoltaic module is sufficient and the air-conditioning operates normally and stably with the real-time required power.

[0033] In some other embodiments, whether the first control process is ended is determined in the following manner: if the duration of the compressor running at the first target speed reaches a set duration, it is determined that the first control process is ended; otherwise, it is determined that the first control process is not ended.

[0034] Figure 2 The flowchart of the second embodiment of the control method of the photovoltaic air conditioning system of the present invention is shown. In this embodiment, the photovoltaic air conditioning system includes a photovoltaic module and an air conditioner. When the photovoltaic air conditioning system is off-grid and the real-time output power of the photovoltaic module is less than the real-time required power of the air conditioning load, the air conditioner is controlled. Figure 1The first control process and the second control process of the embodiment are sequentially controlled. In the first control process, the first target speed is determined according to the real-time DC bus voltage of the air conditioning system, and the air conditioning compressor is controlled to operate according to the first target speed. Moreover, the first target speed is determined by the following process.

[0035] S21: Obtain the difference between the given DC bus voltage and the real-time DC bus voltage as the bus voltage deviation.

[0036] The DC bus voltage is given and known, and the real-time DC bus voltage is obtainable.

[0037] S22: Process the bus voltage deviation to obtain a first compensation speed.

[0038] The first compensation speed is determined according to the bus voltage deviation and changes with the bus voltage deviation. This embodiment does not limit the specific determination method of the first compensation speed. In some embodiments, the bus voltage deviation is processed by proportional integration to obtain the first compensation speed.

[0039] S23: Obtain a difference between the given speed and the first compensation speed as a first compensated speed, and determine the first compensated speed as a first target speed.

[0040] The speed setting is known. In some embodiments, the speed setting is a set value, which is a fixed value.

[0041] In some other embodiments, the rotation speed is set as a variable value.

[0042] In some other embodiments, the speed setting is a dynamically variable value that follows the temperature, humidity, and the speed of the fan of the air conditioner indoor unit, and the speed setting is determined by the following process: Obtain the real-time temperature and humidity of the indoor environment where the photovoltaic air-conditioning system is located, as well as the real-time fan speed of the indoor unit in the photovoltaic air-conditioning system.

[0043] The real-time effective temperature index is determined according to the real-time temperature, the real-time humidity and the real-time fan speed. The specific determination method is not limited and can be implemented by using relevant technologies.

[0044] The difference between the given effective temperature index and the real-time effective temperature index is obtained as the effective temperature index deviation, wherein the given effective temperature index is known.

[0045] The effective temperature deviation is processed to obtain a given speed. The given speed changes with the change of the effective temperature deviation, and this embodiment does not limit the specific determination method. In some embodiments, the effective temperature deviation is processed by proportional integration to obtain the given speed.

[0046] By determining the real-time effective temperature index according to the real-time temperature, real-time humidity and real-time fan speed, and determining the speed setting based on the real-time effective temperature index, so that the speed setting matches the real-time condition of the indoor environment, and then determining the target speed of the compressor according to the speed setting, and controlling the compressor to operate at the target speed, it can adapt to the real-time indoor environment and improve the comfort of the air conditioner in regulating the indoor environment.

[0047] Figure 3 The flowchart of the third embodiment of the control method of the photovoltaic air conditioning system of the present invention is shown. In this embodiment, the photovoltaic air conditioning system includes a photovoltaic module and an air conditioner. When the photovoltaic air conditioning system is off-grid and the real-time output power of the photovoltaic module is less than the real-time required power of the air conditioning load, the air conditioner is sequentially controlled by the first control process and the second control process of the aforementioned embodiment. In the first control process, the first target speed is determined according to the real-time DC bus voltage of the aforementioned air conditioning system, and the air conditioning compressor is controlled to operate according to the first target speed. Moreover, the specific process of controlling the operation of the air conditioning compressor according to the first target speed is as follows.

[0048] S31: Process the first compensation rotation speed to obtain a first rotation speed adjustment step.

[0049] For the method of obtaining the first compensation rotation speed, refer to the description of the above embodiment.

[0050] The first rotation speed adjustment step size changes with the change of the first compensation rotation speed, and this embodiment does not limit the specific determination method.

[0051] In some embodiments, a proportional operation or a proportional integral operation is performed on the first compensation speed to obtain an operation result; then, the operation result is subjected to a limiting process to obtain the first compensation speed. The limiting process of the operation result includes a maximum value limiting process and a minimum value limiting process on the operation result. By performing a limiting process on the operation result to obtain the first compensation speed, it is prevented that the first compensation speed is too large or too small, which affects the operation stability during the subsequent air conditioning control.

[0052] S32: Obtain the real-time rotation speed of the air conditioner, and compare it with the first target rotation speed.

[0053] The method for obtaining the first target speed is described in the above embodiment. The real-time speed of the air conditioner is the speed of the air conditioner compressor obtained in real time according to a set sampling period.

[0054] S33: According to the comparison result, the air-conditioning compressor is controlled to operate in combination with the real-time speed, the first speed adjustment step and the first target speed.

[0055] Specifically, if the real-time speed is less than or equal to the first target speed, the compressor is controlled to increase the speed. Furthermore, when increasing the speed, the real-time speed is used as the base speed, and the first speed adjustment step is used as the speed adjustment step. The real-time speed is increased to obtain the first actual speed, and the air-conditioning compressor is controlled to operate at the first actual speed until the first actual speed increases to the first target speed, and the speed adjustment is stopped. It should be understood that the first actual speed obtained by adding the first speed adjustment step to the current real-time speed will be used as the real-time speed for the next speed adjustment, and the first speed adjustment step will be added on this basis to obtain the next first actual speed. For example, the first real-time speed is recorded as N up , the first speed adjustment step is recorded as N a1 , the first actual speed is recorded as N n1 , then: N n1 = N up +i×N a1 , i is a natural number, indicating the number of adjustments.

[0056] If the real-time speed is greater than the first target speed, the compressor is controlled to reduce the speed. Furthermore, when reducing the speed, the real-time speed is used as the base speed, and the first speed adjustment step is used as the speed adjustment step. The real-time speed is reduced to obtain the second actual speed, and the air-conditioning compressor is controlled to operate at the second actual speed until the second actual speed is reduced to the first target speed. Similarly, the second actual speed obtained by reducing the first speed adjustment step from the current real-time speed will be used as the real-time speed for the next speed adjustment, and the first speed adjustment step will be reduced on this basis to obtain the next second actual speed. For example, the first real-time speed is recorded as N down , the first speed adjustment step is recorded as N a1 , the second actual speed is recorded as N n2 , then: N n2 = N down -j×N a1 , j is a natural number, indicating the number of adjustments.

[0057] In the above embodiment, the first speed adjustment step is dynamically determined according to the first compensation speed, and the first compensation speed is dynamically determined according to the bus voltage deviation, and the bus voltage deviation is dynamically determined according to the given DC bus voltage and the real-time DC bus voltage. Since the real-time DC bus voltage is a non-fixed value, the first speed adjustment step finally determined is also a non-fixed value. Based on the non-fixed first speed adjustment step, the speed of the air-conditioning compressor is dynamically and gradually increased or decreased, so that the speed of the air-conditioning compressor can adapt to the changes in different working conditions of the photovoltaic air-conditioning system, effectively solving the problem of unstable air-conditioning operation caused by sudden changes in the DC bus voltage.

[0058] Figure 4The flowchart of the fourth embodiment of the control method of the photovoltaic air conditioning system of the present invention is shown. In this embodiment, the photovoltaic air conditioning system includes a photovoltaic module and an air conditioner. When the photovoltaic air conditioning system is off-grid and the real-time output power of the photovoltaic module is less than the real-time required power of the air conditioning load, the air conditioner is controlled. Figure 1 The first control process and the second control process of the embodiment are sequentially controlled. In the second control process, the second target speed is determined according to the real-time output power of the photovoltaic module and the real-time required power of the air-conditioning load, and the air-conditioning compressor is controlled to operate according to the second target speed. Moreover, the second target speed is determined by the following process.

[0059] S41: Obtain the difference between the real-time required power of the air conditioning load and the real-time output power of the photovoltaic module as the power deviation.

[0060] The real-time required power of the air-conditioning load and the real-time output power of the photovoltaic module can both be obtained. The obtaining method is described in the above embodiment.

[0061] S42: Process the power deviation to obtain a second compensation rotation speed.

[0062] The second compensation speed is determined according to the power deviation and changes with the change of the power deviation. This embodiment does not limit the specific determination method of the second compensation speed. In some embodiments, the power deviation is processed by proportional integration to obtain the second compensation speed.

[0063] S43: Obtain a difference between the given speed and the second compensation speed as the second compensated speed, and determine the second compensated speed as the second target speed.

[0064] The speed setting is known. In some embodiments, the speed setting is a set value, which is a fixed value.

[0065] In some other embodiments, the rotation speed is set as a variable value.

[0066] In some other embodiments, the speed setting is a dynamically variable value that follows the temperature, humidity, and the speed of the fan of the air conditioner indoor unit, and the speed setting is determined by the following process: Obtain the real-time temperature and humidity of the indoor environment where the photovoltaic air-conditioning system is located, as well as the real-time fan speed of the indoor unit in the photovoltaic air-conditioning system.

[0067] The real-time effective temperature index is determined according to the real-time temperature, the real-time humidity and the real-time fan speed. The specific determination method is not limited and can be implemented by using relevant technologies.

[0068] The difference between the given effective temperature index and the real-time effective temperature index is obtained as the effective temperature index deviation, wherein the given effective temperature index is known.

[0069] The effective temperature deviation is processed to obtain a given speed. The given speed changes with the change of the effective temperature deviation, and this embodiment does not limit the specific determination method. In some embodiments, the effective temperature deviation is processed by proportional integration to obtain the given speed.

[0070] By determining the real-time effective temperature index according to the real-time temperature, real-time humidity and real-time fan speed, and determining the speed setting based on the real-time effective temperature index, so that the speed setting matches the real-time condition of the indoor environment, and then determining the target speed of the compressor according to the speed setting, and controlling the compressor to operate at the target speed, it can adapt to the real-time indoor environment and improve the comfort of the air conditioner in regulating the indoor environment.

[0071] Figure 5 The flowchart of the fifth embodiment of the control method of the photovoltaic air conditioning system of the present invention is shown. In this embodiment, the photovoltaic air conditioning system includes a photovoltaic module and an air conditioner. When the photovoltaic air conditioning system is off-grid and the real-time output power of the photovoltaic module is less than the real-time power demand of the air conditioning load, the air conditioner is sequentially controlled by the first control process and the second control process of the above-mentioned embodiment. In the second control process, the second target speed is determined according to the real-time output power of the photovoltaic module and the real-time power demand of the air conditioning load, and the air conditioning compressor is controlled to operate according to the second target speed. Moreover, the specific process of controlling the operation of the air conditioning compressor according to the second target speed is as follows.

[0072] S51: Process the second compensation rotation speed to obtain a second rotation speed adjustment step.

[0073] For the method of obtaining the second compensation rotation speed, refer to the description of the above embodiment.

[0074] The second rotation speed adjustment step size changes with the change of the second compensation rotation speed, and this embodiment does not limit the specific determination method.

[0075] In some embodiments, a proportional operation or a proportional integral operation is performed on the second compensation speed to obtain an operation result; then, the operation result is subjected to a limiting process to obtain the second compensation speed. The limiting process of the operation result includes a maximum value limiting process and a minimum value limiting process on the operation result. By performing a limiting process on the operation result to obtain the second compensation speed, it is prevented that the second compensation speed is too large or too small, which affects the operation stability during the subsequent air conditioning control.

[0076] S52: Obtain the real-time rotation speed of the air conditioner, and compare it with the second target rotation speed.

[0077] The method for obtaining the second target speed is described in the above embodiment. The real-time speed of the air conditioner is the speed of the air conditioner compressor obtained in real time according to a set sampling period.

[0078] S53: According to the comparison result, the air-conditioning compressor is controlled to operate in combination with the real-time speed, the second speed adjustment step and the second target speed.

[0079] When the real-time speed is less than or equal to the second target speed, the compressor is controlled to increase the speed. Furthermore, when increasing the speed, the real-time speed is used as the base speed, and the second speed adjustment step is used as the speed adjustment step. The real-time speed is increased to obtain a third actual speed, and the air-conditioning compressor is controlled to operate at the third actual speed until the third actual speed increases to the second target speed, and the speed adjustment is stopped. It should be understood that the third actual speed obtained by adding the second speed adjustment step to the current real-time speed will be used as the real-time speed for the next speed adjustment, and the second speed adjustment step will be added to obtain the next third actual speed. For example, the first real-time speed is still recorded as N up , the second speed adjustment step is recorded as N a2 , the third actual speed is recorded as N n3 , then: N n3 = N up +k×N a2 , k is a natural number, indicating the number of adjustments.

[0080] If the real-time speed is greater than the second target speed, the compressor is controlled to reduce the speed. Furthermore, when reducing the speed, the real-time speed is used as the base speed and the second speed adjustment step length is used as the speed adjustment step length to reduce the real-time speed to obtain a fourth actual speed. The air-conditioning compressor is controlled to operate at the fourth actual speed until the fourth actual speed is reduced to the second target speed. Similarly, the fourth actual speed obtained by reducing the second speed adjustment step length from the current real-time speed will be used as the real-time speed for the next speed adjustment. On this basis, the second speed adjustment step length will be reduced to obtain the next fourth actual speed. For example, the first real-time speed is still recorded as N down , the second speed adjustment step is recorded as N a2 , the fourth actual speed is recorded as N n4 , then: N n4 = N down -m×N a2 , m is a natural number, indicating the number of adjustments.

[0081] In the above embodiment, the second speed adjustment step is dynamically determined according to the second compensation speed, and the second compensation speed is dynamically determined according to the power deviation, and the power deviation is dynamically determined according to the real-time power demand of the air-conditioning load and the real-time output power of the photovoltaic module. Since the real-time power demand of the air-conditioning load and the real-time output power of the photovoltaic module are usually non-fixed values, the second speed adjustment step determined at last is also a non-fixed value. Then, based on the non-fixed second speed adjustment step, the speed of the air-conditioning compressor is dynamically and gradually increased or decreased, so that the speed of the air-conditioning compressor can adapt to the changes in different working conditions of the photovoltaic air-conditioning system, and effectively solve the problem of unstable air-conditioning operation caused by sudden changes in the power demand of the air-conditioning load and / or the output power of the photovoltaic module.

[0082] Figure 6 The schematic diagram of the structure of an embodiment of the control device of the photovoltaic air conditioning system of the present invention is shown. In this embodiment, the photovoltaic air conditioning system includes a photovoltaic module and an air conditioner, and the air conditioner can be powered by a power grid and / or a photovoltaic module. The control device of this embodiment includes structural units, functions of the structural units, and relationships between them, as follows: The control device includes: The real-time output power acquisition unit 61 of the photovoltaic module is used to acquire the real-time output power of the photovoltaic module in the photovoltaic air-conditioning system.

[0083] The real-time required power acquisition unit 62 of the air-conditioning load is used to acquire the real-time required power of the air-conditioning load in the photovoltaic air-conditioning system.

[0084] The control unit 63 is used to execute the first control process and the second control process when the photovoltaic air-conditioning system is in an off-grid state and the real-time output power of the photovoltaic module obtained by the real-time output power acquisition unit 61 of the photovoltaic module is less than the real-time required power of the air-conditioning load obtained by the real-time required power acquisition unit 62 of the air-conditioning load. The first control process includes: determining the first target speed according to the real-time DC bus voltage of the photovoltaic air-conditioning system, and controlling the operation of the air-conditioning compressor according to the first target speed, so that the operation of the air-conditioning follows the change of the DC bus voltage. The second control process includes: after the first control process is completed, determining the second target speed according to the real-time output power of the photovoltaic module and the real-time required power of the air-conditioning load, and controlling the operation of the air-conditioning compressor according to the second target speed, so that the operation of the air-conditioning follows the change of power supply and demand.

[0085] The control device of the above structure runs the corresponding software program and performs the corresponding functions according to Figure 1 The photovoltaic air conditioning system is controlled by the control method embodiment and the process of other embodiments to achieve the same Figure 1 The corresponding technical effects of the embodiment and other embodiments.

[0086] The control devices of the above-mentioned embodiments are applied to a photovoltaic air-conditioning system, which can improve the continuous operation stability of the photovoltaic air-conditioning system and ensure the use of the air-conditioning system.

[0087] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for a person skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to replace some of the technical features therein by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions claimed to be protected by the present invention.

Claims

1. A control method for a photovoltaic air conditioning system, characterized in that: The control method comprises: Obtain the real-time output power of the photovoltaic components in the photovoltaic air-conditioning system and the real-time required power of the air-conditioning load; When the photovoltaic air-conditioning system is in an off-grid state and the real-time output power of the photovoltaic module is less than the real-time required power of the air-conditioning load, the following first control process and second control process are sequentially executed; The first control process includes: determining a first target speed according to a real-time DC bus voltage of the photovoltaic air conditioning system, and controlling the operation of the air conditioning compressor according to the first target speed so that the operation of the air conditioning follows the change of the DC bus voltage; The second control process includes: after the first control process is completed, determining a second target speed according to the real-time output power of the photovoltaic component and the real-time required power of the air-conditioning load, and controlling the operation of the air-conditioning compressor according to the second target speed so that the operation of the air-conditioning follows the changes in power supply and demand.

2. The control method of the photovoltaic air conditioning system according to claim 1, characterized in that: Determining the first target speed according to the real-time DC bus voltage of the photovoltaic air conditioning system specifically includes: Obtaining a difference between a given DC bus voltage and the real-time DC bus voltage as a bus voltage deviation; Processing the bus voltage deviation to obtain a first compensation speed; Obtaining a difference between a given speed and the first compensation speed as a first compensated speed; The first compensated rotational speed is determined as the first target rotational speed.

3. The control method of the photovoltaic air conditioning system according to claim 2, characterized in that: Controlling the operation of the air-conditioning compressor according to the first target speed specifically includes: Processing the first compensation speed to obtain a first speed adjustment step; Obtaining a real-time speed of the air-conditioning compressor and comparing it with the first target speed; When the real-time speed is less than or equal to the first target speed, the real-time speed is used as the base speed, the first speed adjustment step length is used as the speed adjustment step length, the real-time speed is increased to obtain a first actual speed, and the air-conditioning compressor is controlled to operate at the first actual speed until the first actual speed increases to the first target speed; When the real-time speed is greater than the first target speed, the real-time speed is used as the base speed, and the first speed adjustment step is used as the speed adjustment step to reduce the real-time speed to obtain the second actual speed, and the air-conditioning compressor is controlled to operate at the second actual speed until the second actual speed is reduced to the first target speed.

4. The control method of the photovoltaic air conditioning system according to claim 3, characterized in that: Processing the first compensation speed to obtain a first speed adjustment step size specifically includes: Performing a proportional operation or a proportional integral operation on the first compensation speed to obtain an operation result; The calculation result is limited to obtain the first speed adjustment step.

5. The control method of the photovoltaic air conditioning system according to claim 1, characterized in that: Determining the second target speed according to the real-time output power of the photovoltaic assembly and the real-time required power of the air conditioning load specifically includes: Obtaining a difference between the real-time required power of the air-conditioning load and the real-time output power of the photovoltaic module as a power deviation; Processing the power deviation to obtain a second compensation rotation speed; Obtaining a difference between a given speed and the second compensation speed as a second compensated speed; The second compensated rotational speed is determined as the second target rotational speed.

6. The control method of the photovoltaic air conditioning system according to claim 5, characterized in that: Controlling the operation of the air-conditioning compressor according to the second target speed specifically includes: Processing the second compensation speed to obtain a second speed adjustment step length; Obtaining a real-time speed of the air-conditioning compressor, and comparing it with the second target speed; When the real-time speed is less than or equal to the second target speed, taking the real-time speed as the base speed and the second speed adjustment step as the speed adjustment step, increasing the real-time speed to obtain a third actual speed, and controlling the operation of the air-conditioning compressor with the third actual speed until the third actual speed increases to the second target speed; When the real-time speed is greater than the second target speed, the real-time speed is used as the base speed, and the second speed adjustment step is used as the speed adjustment step to reduce the real-time speed to obtain a fourth actual speed, and the air-conditioning compressor is controlled to operate at the fourth actual speed until the fourth actual speed is reduced to the second target speed.

7. The control method of the photovoltaic air conditioning system according to claim 6, characterized in that: Processing the second compensation speed to obtain a second speed adjustment step size specifically includes: Performing a proportional operation or a proportional integral operation on the second compensation speed to obtain an operation result; The calculation result is limited to obtain the second speed adjustment step.

8. The control method of the photovoltaic air conditioning system according to claim 2 or 5, characterized in that: The speed setting is determined by the following process: Obtain the real-time temperature and humidity of the indoor environment where the photovoltaic air-conditioning system is located and the real-time fan speed of the indoor unit in the photovoltaic air-conditioning system; Determine a real-time effective temperature index according to the real-time temperature, the real-time humidity and the real-time fan speed; Obtaining a difference between a given effective temperature index and the real-time effective temperature index as an effective temperature index deviation; The effective temperature deviation is processed to obtain the rotational speed setting.

9. A control device for a photovoltaic air conditioning system, characterized in that: The control device comprises: A real-time output power acquisition unit of a photovoltaic module, used to acquire the real-time output power of a photovoltaic module in a photovoltaic air-conditioning system; The real-time power demand acquisition unit of the air-conditioning load is used to acquire the real-time power demand of the air-conditioning load in the photovoltaic air-conditioning system; A control unit, configured to sequentially execute the following first control process and second control process when the photovoltaic air conditioning system is in an off-grid state and the real-time output power of the photovoltaic module is less than the real-time required power of the air conditioning load; The first control process includes: determining a first target speed according to a real-time DC bus voltage of the photovoltaic air conditioning system, and controlling the operation of the air conditioning compressor according to the first target speed so that the operation of the air conditioning follows the change of the DC bus voltage; The second control process includes: after the first control process is completed, determining a second target speed according to the real-time output power of the photovoltaic component and the real-time required power of the air-conditioning load, and controlling the operation of the air-conditioning compressor according to the second target speed so that the operation of the air-conditioning follows the changes in power supply and demand.

10. A photovoltaic air conditioning system, comprising a photovoltaic module and an air conditioner, characterized in that: The photovoltaic air-conditioning system also includes the control device of the photovoltaic air-conditioning system as described in claim 9 above.

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