Photovoltaic air conditioner, and control method and control apparatus therefor

Abstract

Disclosed in the present invention are a photovoltaic air conditioner, and a control method and control apparatus therefor. The method comprises: when a real-time target frequency of a photovoltaic air conditioner meets a set frequency condition, executing the following first control process: when a real-time air conditioner target power of the photovoltaic air conditioner is greater than a real-time photovoltaic output power of a photovoltaic array, performing photovoltaic multi-peak power scanning to obtain a photovoltaic maximum power point, and adjusting the actual operating frequency of the photovoltaic air conditioner on the basis of the photovoltaic maximum power point; or when the real-time air conditioner target power is not greater than the real-time photovoltaic output power, controlling the photovoltaic air conditioner to operate at the real-time target frequency; alternatively, when the real-time target frequency does not meet the set frequency condition, executing the following second control process: performing photovoltaic multi-peak power scanning to obtain a photovoltaic maximum power point, and adjusting the actual operating frequency of the photovoltaic air conditioner on the basis of the photovoltaic maximum power point. By means of the present invention, the operating stability of photovoltaic air conditioners can be improved.

Description

Photovoltaic air conditioning and its control methods and devices Technical Field

[0001] This invention belongs to the field of energy-saving air conditioning technology, specifically, it relates to photovoltaic air conditioners and their control methods and devices. Background Technology

[0002] As an energy-saving type of air conditioner, photovoltaic air conditioning has been widely used in many fields such as production and daily life due to the increasingly urgent need for energy conservation and emission reduction and the continuous maturation of photovoltaic technology.

[0003] Photovoltaic air conditioners utilize photovoltaic (PV) arrays within photovoltaic modules to convert solar energy into electrical energy, providing the power required for their operation. The performance of PV arrays is significantly affected by the environment. In unshaded environments, PV arrays typically have only one maximum power point (MPP). Traditional maximum power point tracking (MPPT) algorithms can effectively and quickly track this MPP, allowing the PV array to stably output maximum power and ensuring stable operation of the air conditioner. However, if the PV array is shaded, not only does its maximum power decrease, but multiple peak power points also appear. While existing technologies exist for tracking the MPP from multiple peak power points, the MPP tracking process is complex and has low accuracy, preventing the PV array from quickly, effectively, and stably outputting maximum power, thus affecting the stable operation of the air conditioner. Technical issues

[0004] One of the objectives of this invention is to provide a photovoltaic air conditioning control method and control device to improve the stability of photovoltaic air conditioning operation. Technical solutions

[0005] To achieve the above-mentioned objectives, the photovoltaic air conditioning control method provided by this invention adopts the following technical solution:

[0006] A photovoltaic air conditioning control method, comprising:

[0007] Obtain the real-time target frequency of the photovoltaic air conditioner;

[0008] When the real-time target frequency meets the set frequency condition, the following first control procedure is executed:

[0009] Obtain the real-time target power of the photovoltaic air conditioner and the real-time photovoltaic output power of the photovoltaic array;

[0010] When the real-time target power of the air conditioner is greater than the real-time photovoltaic output power, a photovoltaic multi-power peak scan is performed to obtain the photovoltaic maximum power point, and the actual operating frequency of the photovoltaic air conditioner is adjusted according to the photovoltaic maximum power point; when the real-time target power of the air conditioner is not greater than the real-time photovoltaic output power, the photovoltaic air conditioner is controlled to operate according to the real-time target frequency.

[0011] When the real-time target frequency does not meet the set frequency condition, the following second control process is executed:

[0012] Perform the photovoltaic multi-power peak scan to obtain the photovoltaic maximum power point, and adjust the actual operating frequency of the photovoltaic air conditioner according to the photovoltaic maximum power point;

[0013] The set frequency conditions include any one of the following: low frequency operation mode, less than the set frequency limit, or less than the set frequency range.

[0014] In some embodiments of this application, performing the photovoltaic multi-power peak scan to obtain the photovoltaic maximum power point specifically includes:

[0015] On the photovoltaic power-voltage curve, the operating point with the open-circuit voltage is taken as the initial search point. The search proceeds in the direction of decreasing voltage until the first peak power point is found. The first voltage and the first power corresponding to the first peak power point are recorded.

[0016] The difference voltage is determined based on the first voltage; the difference voltage is less than the first voltage.

[0017] The operating point where the voltage equals the voltage difference is used as the new search starting point to continue the search. The peak power point found in the subsequent search is recorded as the most recent peak power point, and the voltage and power corresponding to the most recent peak power point are recorded.

[0018] The sum of the voltage corresponding to the most recent peak power point and the difference voltage is used as the voltage of the next search starting point;

[0019] Determine whether the difference between the first voltage and the voltage of the next search starting point is less than the difference voltage; if not, take the operating point with a voltage equal to the voltage of the next search starting point as the new search starting point and continue searching; until the difference between the first voltage and the voltage of the next search starting point is less than the difference voltage, then stop searching;

[0020] After stopping the search, the point with the highest power among all the peak power points found is determined as the photovoltaic maximum power point.

[0021] In some embodiments of this application, determining the difference voltage based on the first voltage specifically includes:

[0022] The number N of the photovoltaic array connected in series is obtained, and the difference voltage is determined based on the first voltage and the number N. The difference voltage is positively correlated with the first voltage and negatively correlated with the number N.

[0023] In other embodiments of this application, determining the difference voltage based on the first voltage specifically includes:

[0024] In the first control process, the power difference between the real-time air conditioning target power and the real-time photovoltaic output power is obtained, and the difference voltage is determined based on the first voltage and the power difference. The difference voltage is positively correlated with the first voltage and negatively correlated with the power difference.

[0025] In the second control process, the frequency difference between the real-time target frequency and the set frequency value is obtained, and the difference voltage is determined based on the first voltage and the frequency difference. The difference voltage is positively correlated with the first voltage and negatively correlated with the frequency difference. The set frequency value is determined based on the set frequency condition.

[0026] In other embodiments of this application, determining the difference voltage based on the first voltage specifically includes:

[0027] During the first control process, the power difference between the real-time target power of the air conditioner and the real-time photovoltaic output power is obtained, and the number N of the solar panels connected in series in the photovoltaic array is also obtained. The difference voltage is determined based on the first voltage, the power difference, and the number N. The difference voltage is positively correlated with the first voltage, negatively correlated with the power difference, and negatively correlated with the number N.

[0028] During the second control process, the frequency difference between the real-time target frequency and the set frequency value is obtained, and the number N of the photovoltaic array connected in series is also obtained. The difference voltage is determined based on the first voltage, the frequency difference, and the number N. The difference voltage is positively correlated with the first voltage, negatively correlated with the frequency difference, and negatively correlated with the number N. The set frequency value is determined based on the set frequency condition.

[0029] In some embodiments of this application, the first control process further includes:

[0030] When the real-time target power of the air conditioner is greater than the real-time output power of the photovoltaic system, the number of times the photovoltaic air conditioner operates at reduced frequency in real-time is also obtained.

[0031] When the number of real-time frequency reduction operations is less than a preset threshold, the actual intermittent operation mode corresponding to the actual operating frequency is determined according to the correspondence between the operating frequency and the intermittent operation mode; the intermittent operation mode includes at least continuous operating time and downtime;

[0032] The operation of the photovoltaic air conditioner is controlled according to the actual operating frequency and the actual intermittent operating mode.

[0033] In some embodiments of this application, the continuous running time in the intermittent operation mode is a variable value and is determined using the following formula:

[0034] T = k1 × f + k2 × n;

[0035] Where T is the continuous running time, f is the actual running frequency, n is the number of times the real-time frequency reduction operation is performed, k1 is a known coefficient greater than 0, and k2 is a known coefficient less than 0.

[0036] In some embodiments of this application, the downtime in the intermittent operation mode is a variable value and is determined using the following formula:

[0037] t = k3 × n;

[0038] Where t is the downtime, n is the number of times the real-time frequency reduction operation is performed, and k3 is a known coefficient greater than 0.

[0039] To achieve the aforementioned objectives, the photovoltaic air conditioning control device provided by this invention employs the following technical solution:

[0040] A photovoltaic air conditioning control device, comprising:

[0041] Real-time target frequency acquisition unit, used to acquire the real-time target frequency of photovoltaic air conditioner;

[0042] A real-time air conditioning target power acquisition unit is used to acquire the real-time air conditioning target power of the photovoltaic air conditioner.

[0043] A real-time photovoltaic output power acquisition unit is used to acquire the real-time photovoltaic output power of the photovoltaic array in a photovoltaic air conditioner.

[0044] An execution unit is configured to execute a first control process when the real-time target frequency meets the set frequency condition and to execute a second control process when the real-time target frequency does not meet the set frequency condition.

[0045] The first control process includes: when the real-time air conditioner target power is greater than the real-time photovoltaic output power, performing photovoltaic multi-power peak scanning to obtain the photovoltaic maximum power point, and adjusting the actual operating frequency of the photovoltaic air conditioner according to the photovoltaic maximum power point; when the real-time air conditioner target power is not greater than the real-time photovoltaic output power, controlling the photovoltaic air conditioner to operate according to the real-time target frequency;

[0046] The second control process includes: performing the photovoltaic multi-power peak scan to obtain the photovoltaic maximum power point, and adjusting the actual operating frequency of the photovoltaic air conditioner according to the photovoltaic maximum power point;

[0047] The set frequency conditions include any one of the following: low frequency operation mode, less than the set frequency limit, or less than the set frequency range.

[0048] Another object of the present invention is to provide a photovoltaic air conditioner, including an air conditioner body and a photovoltaic array, wherein the photovoltaic air conditioner also includes the aforementioned photovoltaic air conditioner control device. Beneficial effects

[0049] Compared with the prior art, the advantages and positive effects of the present invention are:

[0050] The photovoltaic air conditioner and its control method and device provided by this invention, when the real-time target frequency of the photovoltaic air conditioner is low-frequency operation condition that meets the set frequency conditions, acquires and compares the real-time target power required by the air conditioner and the real-time photovoltaic output power that the photovoltaic array can provide. When the real-time target power of the air conditioner is greater than the real-time photovoltaic output power, the photovoltaic output cannot meet the actual needs of the air conditioner. At this time, a photovoltaic multi-power peak scan is performed to obtain the photovoltaic maximum power point, and the actual operating frequency of the photovoltaic air conditioner is adjusted according to the photovoltaic maximum power point to supply the air conditioner with the maximum photovoltaic output power, so as to meet the air conditioner's needs as much as possible. At the same time, it also makes the air conditioner's operation adapt to the instability of photovoltaic input, improving the stability of the air conditioner's operation. Under low-frequency operation conditions, if the real-time target power of the air conditioner is... If the photovoltaic output power is not greater than the real-time photovoltaic output power, the photovoltaic output can basically meet the actual needs of the air conditioner even if it does not operate at the maximum power point. In this case, photovoltaic multi-power peak scanning is not performed, and the air conditioner operates directly according to the real-time target frequency, avoiding the complexity of multi-power peak scanning and the instability of air conditioner operation caused by inaccurate scanning. However, if the real-time target frequency of the photovoltaic air conditioner is a non-low-frequency operating condition that does not meet the set frequency conditions, the power demand of the air conditioner is large. Therefore, the relationship between the real-time target power required by the air conditioner and the real-time photovoltaic output power that the photovoltaic array can provide is not considered. Photovoltaic multi-power peak scanning is performed to obtain the photovoltaic maximum power point, and the actual operating frequency of the photovoltaic air conditioner is adjusted according to the photovoltaic maximum power point. This improves the stability of air conditioner operation while meeting the air conditioner's needs as much as possible.

[0051] Other features and advantages of the present invention will become clearer after reading the detailed embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0053] Figure 1 is a flowchart of an embodiment of the photovoltaic air conditioning control method of the present invention;

[0054] Figure 2 is a flowchart of another embodiment of the photovoltaic air conditioning control method of the present invention;

[0055] Figure 3 is a schematic diagram of an embodiment of the photovoltaic air conditioning control device of the present invention. Embodiments of the present invention

[0056] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0057] It should be noted that the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they can be implemented by those skilled in the art. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0058] Figure 1 shows a flowchart of an embodiment of the photovoltaic air conditioning control method of the present invention.

[0059] As shown in Figure 1, this embodiment uses the following process control photovoltaic air conditioner.

[0060] S101: Obtain the real-time target frequency of the photovoltaic air conditioner.

[0061] The real-time target frequency is the target frequency of the compressor in the photovoltaic air conditioner, which is obtained in real time according to the set sampling frequency. The acquisition of the real-time target frequency is achieved using existing technology, which will not be specifically described or limited here.

[0062] S102: Determine whether the real-time target frequency meets the set frequency conditions, and execute different control processes based on the determination result.

[0063] The set frequency conditions are those that characterize the low-frequency operation of the air conditioner. Specifically, the set frequency conditions include any one of the following: low-frequency operation mode, frequency below the set frequency limit, or frequency below the set frequency range.

[0064] If the real-time target frequency meets the set frequency condition, it indicates that the air conditioner is operating in a low-frequency mode. In some embodiments, the set frequency condition is a low-frequency operating mode; if the real-time target frequency meets the low-frequency operating mode, it indicates that the air conditioner is operating in a low-frequency mode. In other embodiments, the set frequency condition is less than a set frequency limit; if the real-time target frequency is less than the set frequency limit, it indicates that the air conditioner is operating in a low-frequency mode. In still other embodiments, the set frequency condition is less than a set frequency range; if the real-time target frequency is less than a frequency within the set frequency range, it indicates that the air conditioner is operating in a low-frequency mode.

[0065] S103: Execute the first control process.

[0066] When S102 determines that the real-time target frequency meets the set frequency condition, indicating that the air conditioner is in low-frequency operation mode, the first control process from S103 to S107 is executed.

[0067] S104: Obtain the real-time target power P1 of the photovoltaic air conditioner and the real-time photovoltaic output power P2 of the photovoltaic array.

[0068] In the first control process, the real-time target power P1 of the photovoltaic air conditioner and the real-time photovoltaic output power P2 of the photovoltaic array are first acquired. The real-time target power of the air conditioner is the operating power required by the photovoltaic air conditioner, which is acquired in real time according to the set sampling frequency, while the real-time photovoltaic output power of the photovoltaic array is the output power that the photovoltaic array in the photovoltaic air conditioner can provide, which is acquired in real time according to the set sampling frequency. The methods for acquiring both powers are implemented using existing technologies, and will not be specifically described or limited here.

[0069] S105: Determine whether P1 > P2 is satisfied, and execute the control process of S106 or S107 according to the determination result.

[0070] S106: Perform photovoltaic multi-power peak scanning to obtain the photovoltaic maximum power point, and adjust the actual operating frequency of the photovoltaic air conditioner according to the photovoltaic maximum power point.

[0071] When S105 determines that P1 > P2, i.e., the real-time air conditioning target power is greater than the real-time photovoltaic output power, a photovoltaic multi-power peak scan is performed to obtain the photovoltaic maximum power point. Then, the actual operating frequency of the photovoltaic air conditioner is adjusted according to the photovoltaic maximum power point. Since the real-time air conditioning target power is greater than the real-time photovoltaic output power, the photovoltaic output power cannot meet the actual power requirements of the air conditioner. Therefore, the frequency of the air conditioner's compressor is adjusted according to the power that can be output from the photovoltaic maximum power point tracked by the scan. Specifically, the compressor operating frequency is reduced to maintain the operation of the air conditioner at a low frequency, avoiding compressor shutdown due to insufficient photovoltaic output power to support the compressor operating at the real-time target frequency. At the same time, the actual operating frequency of the air conditioner is adjusted according to the tracked photovoltaic maximum power point so that the air conditioner can utilize the output power at the photovoltaic maximum power point to the maximum extent possible to meet the air conditioner's operating requirements.

[0072] S107: Control the photovoltaic air conditioner to operate at the real-time target frequency.

[0073] When S105 determines that P1 > P2 is not satisfied, that is, when the real-time air conditioning target power is not greater than the real-time photovoltaic output power, the photovoltaic output can basically meet the actual needs of the air conditioning even if it does not operate at the maximum power point. Therefore, in this case, photovoltaic multi-power peak scanning is not performed, and the air conditioning operates directly according to the real-time target frequency to meet the air conditioning operation requirements. By not performing photovoltaic multi-power peak scanning, the complexity of multi-power peak scanning and the occurrence of air conditioning instability caused by inaccurate scanning are effectively avoided.

[0074] If S102 determines that the real-time target frequency does not meet the set frequency conditions, it indicates that the air conditioner is in a non-low frequency operating condition and will proceed to S108.

[0075] S108: Execute the second control process.

[0076] S109: Perform photovoltaic multi-power peak scanning to obtain the photovoltaic maximum power point, and adjust the actual operating frequency of the photovoltaic air conditioner according to the photovoltaic maximum power point.

[0077] If the air conditioner is not operating at low frequency and has a high power demand, the power effect will no longer be considered. Instead, a photovoltaic multi-power peak scan will be performed, and the actual operating frequency of the photovoltaic air conditioner will be adjusted based on the maximum power point of the photovoltaic obtained from the scan, so as to improve the stability of the air conditioner operation while meeting the air conditioner's needs as much as possible.

[0078] In the above embodiments, the photovoltaic multi-power peak scanning tracking and frequency control of the photovoltaic air conditioner are selectively executed based on the real-time target frequency, real-time target power of the air conditioner and the real-time photovoltaic output power of the photovoltaic array. This can improve the stability of air conditioner operation while meeting the air conditioner's needs as much as possible under various operating conditions.

[0079] Figure 2 shows a flowchart of another embodiment of the photovoltaic air conditioning control method of the present invention. Specifically, it is a flowchart of an embodiment in which the first control process is executed when the real-time target frequency meets the set frequency condition.

[0080] As shown in Figure 2, this embodiment uses the following process control photovoltaic air conditioner.

[0081] S201: During the first control process, when the real-time target power of the air conditioner is greater than the real-time photovoltaic output power, the number of real-time frequency reduction operations is obtained.

[0082] The conditions for entering the first control process are described in the embodiment of Figure 1. The meaning and acquisition method of the real-time air conditioning target power and real-time photovoltaic output power are also described in the embodiment of Figure 1. During the first control process, when the real-time air conditioning target power is greater than the real-time photovoltaic output power, the photovoltaic multi-power peak scanning process of the embodiment of Figure 1 is still executed, and the actual operating frequency of the photovoltaic air conditioner is adjusted according to the photovoltaic maximum power point. Furthermore, since the real-time air conditioning target power is greater than the real-time photovoltaic output power, the photovoltaic output power cannot meet the actual power requirements of the air conditioner, and the photovoltaic air conditioner typically operates at a reduced frequency.

[0083] In this embodiment, when the real-time target power of the air conditioner is greater than the real-time photovoltaic output power, the number of real-time frequency reduction operations is acquired. The number of frequency reduction operations reflects the number of times the photovoltaic air conditioner operates at a reduced frequency within a certain period because the real-time photovoltaic output power is less than the real-time target power of the air conditioner. Its initial value is 0. As long as the real-time photovoltaic output power is continuously less than the real-time target power of the air conditioner, its value is incremented by 1 each time the condition of frequency reduction due to less than the real-time target power of the air conditioner is met; when the condition of frequency reduction due to less than the real-time target power of the air conditioner is not met, its value is reset to zero. The number of real-time frequency reduction operations is the stored value of the number of frequency reduction operations acquired when entering the first control process and the real-time target power of the air conditioner is greater than the real-time photovoltaic output power.

[0084] S202: When the number of real-time frequency reduction operations is less than the preset threshold, the actual intermittent operation mode corresponding to the actual operating frequency is determined according to the correspondence between the operating frequency and the intermittent operation mode.

[0085] After obtaining the number of real-time frequency reduction operations, it is compared with a preset threshold. If the number of real-time frequency reduction operations is less than the preset threshold, frequency reduction processing is performed, that is, the actual operating frequency of the photovoltaic air conditioner is adjusted according to the photovoltaic maximum power point.

[0086] Simultaneously, an intermittent operation mode is defined. Specifically, a correspondence between operating frequency and intermittent operation mode is preset, and the intermittent operation mode includes at least continuous operating time and shutdown time. The continuous operating time is the duration of continuous operation of the photovoltaic air conditioner after entering the intermittent operation mode. It should be understood that the photovoltaic air conditioner will shut down after the continuous operating time is reached. The shutdown time is the duration of shutdown after the continuous operating time is reached after entering the intermittent operation mode. It should be understood that the photovoltaic air conditioner will restart operation after the shutdown duration is reached.

[0087] The preset correspondence between operating frequency and intermittent operating mode includes at least one corresponding intermittent operating mode for different operating frequency values, which corresponds to a continuous operating time and a downtime.

[0088] After determining the actual operating frequency of the photovoltaic air conditioner based on the photovoltaic maximum power point, the actual intermittent operating mode corresponding to the actual operating frequency can be obtained according to the preset correspondence between the operating frequency and the intermittent operating mode. Then, the continuous operating time and the downtime in the actual intermittent operating mode are determined as the actual continuous operating time and the actual downtime, respectively.

[0089] S203: Control the operation of the photovoltaic air conditioner according to the actual operating frequency and the actual intermittent operating mode.

[0090] Specifically, the photovoltaic air conditioner is controlled to operate at the actual operating frequency, and the continuous operating time is the actual continuous operating time; then the photovoltaic air conditioner is controlled to shut down, and the shutdown time is the actual shutdown time; after the shutdown time reaches the actual shutdown time, the photovoltaic air conditioner is controlled to restart.

[0091] In some other embodiments, after the downtime of the photovoltaic air conditioner stops according to the actual intermittent operation mode reaches the actual downtime, the photovoltaic air conditioner is controlled to start up. Then, the process of obtaining the number of real-time frequency reduction operations and making judgments and subsequent processing is executed again to realize the cyclic automatic operation control of the photovoltaic air conditioner.

[0092] In the above embodiments, during the first control process, when the real-time target power of the air conditioner is greater than the real-time photovoltaic output power, the number of frequency reduction operations is used as a reference quantity. When the number of real-time frequency reduction operations is less than a preset threshold, after obtaining the actual operating frequency of the air conditioner compressor after frequency reduction, the actual intermittent operation mode corresponding to the actual operating frequency is determined, and the photovoltaic air conditioner is controlled based on the actual operating frequency and the actual intermittent operation mode. Therefore, when the real-time photovoltaic output power is less than the real-time target power of the air conditioner, the air conditioner compressor is not controlled to operate continuously at low frequency. Instead, by setting the number of frequency reduction operations and the intermittent operation mode, different parameters and methods are used to adjust the low-frequency operation time of the compressor. The photovoltaic air conditioner stops after running for a period of time, and restarts after a certain period of shutdown. The continuous operation time and the shutdown duration are closely related to the actual operating frequency, thereby reasonably and reliably reducing the continuous low-frequency operation time of the compressor. Therefore, it is possible to maintain the operation of the photovoltaic air conditioner as much as possible while avoiding problems such as compressor wear, reduced reliability and service life of the compressor and photovoltaic air conditioning system, excessive noise, and loosening or even breakage of air conditioning pipes caused by the compressor running at low frequency for a long time. This achieves a balance between the reliability of photovoltaic air conditioner operation and the comfort of using photovoltaic air conditioner, and further improves the stability of photovoltaic air conditioner operation.

[0093] In some embodiments, the continuous running time and downtime in the intermittent operation mode may be fixed values.

[0094] In some other embodiments, the continuous running time and downtime in the intermittent operation mode are both variable values.

[0095] For the variable continuous operating time in intermittent operation mode, the following formula is used to determine it: T = k1 × f + k2 × n. Where T is the continuous operating time, f is the actual operating frequency, n is the number of real-time frequency reduction operations, k1 is a known coefficient greater than 0, and k2 is a known coefficient less than 0. That is, the continuous operating time is jointly determined by the actual operating frequency and the number of real-time frequency reduction operations, and the continuous operating time is positively correlated with the actual operating frequency, but negatively correlated with the actual number of frequency reduction operations. Controlling the photovoltaic air conditioner based on this determined continuous operating time can further improve the balance between the reliability of photovoltaic air conditioner operation and the comfort of using it.

[0096] For the variable downtime in intermittent operation mode, the following formula is used to determine it: t = k3 × n. Where t is the downtime, n is the number of real-time frequency reduction operations, and k3 is a known coefficient greater than 0. That is, the downtime is determined based on the number of real-time frequency reduction operations, and the two are positively correlated. Determining the downtime in this way allows for adaptive adjustment based on the output power status of the photovoltaic array, minimizing the low-frequency operation time of the compressor and further improving the stability of the photovoltaic air conditioner operation.

[0097] In some other embodiments, during the first control process, if the real-time air conditioning target power is greater than the real-time photovoltaic output power, and the number of times the real-time frequency reduction operation is not less than a preset threshold, it indicates that the photovoltaic air conditioning has repeatedly reduced its frequency because the real-time photovoltaic output power cannot meet the real-time air conditioning target power. This state indicates that the current lighting conditions are poor, and the photovoltaic array cannot provide sufficient output power in a short period of time. To protect the photovoltaic air conditioning and avoid the compressor from running at low frequency for a long time, the photovoltaic air conditioning will be controlled to shut down.

[0098] The method for obtaining the maximum power point of photovoltaics by multi-power peak scanning can be implemented using existing technologies.

[0099] In other instances, to improve scanning speed and accuracy, photovoltaic multi-power peak scanning is performed to obtain the photovoltaic maximum power point, specifically including:

[0100] On the photovoltaic power-voltage curve, the operating point where the voltage is the open-circuit voltage is used as the initial search point. The search proceeds in the direction of decreasing voltage until the first peak power point is found. The first voltage and the first power corresponding to the first peak power point are recorded. The search method employs existing technologies, such as the perturbation-observation method.

[0101] The difference voltage is determined based on the first voltage, and the difference voltage is less than the first voltage. The specific determination method is preset.

[0102] The operating point where the voltage equals the voltage difference is used as the new starting point for the search. The peak power point found in the subsequent search is recorded as the most recent peak power point, and the voltage and power corresponding to the most recent peak power point are recorded.

[0103] The sum of the voltage corresponding to the most recent peak power point and the voltage difference is used as the voltage of the next search starting point;

[0104] Before continuing the search, first determine whether the difference between the first voltage and the voltage of the next search starting point is less than the difference voltage; if not, take the operating point with a voltage equal to the voltage of the next search starting point as the new search starting point and continue the search; until the difference between the first voltage and the voltage of the next search starting point is less than the difference voltage, then stop the search.

[0105] It should be understood that if the difference between the first voltage and the voltage of the next search starting point is not less than the difference voltage, the operating point whose voltage equals the voltage of the next search starting point is used as the new search starting point to continue the search. After finding the peak power point, it is taken as the most recent peak power point, and the voltage and power corresponding to the peak power point are recorded. Then, the sum of the voltage corresponding to the peak power point and the difference voltage is used as the voltage of the next search starting point, and the above voltage judgment process is repeated.

[0106] After the search stops, the point with the highest power among all the peak power points found is determined as the photovoltaic maximum power point.

[0107] In the aforementioned multi-power peak scanning process, since the operating point with voltage equal to the voltage difference is used as the new search starting point, the magnitude of the voltage difference limits the search range. Furthermore, the sum of the voltage corresponding to the most recent peak power point and the voltage difference is used as the voltage of the next search starting point; therefore, the magnitude of the voltage difference also determines the distance between the next search starting point and the most recent peak power point. Before continuing the search, it is necessary to determine whether the difference between the first voltage and the voltage of the next search starting point is less than the voltage difference; therefore, the magnitude of the voltage difference also determines whether to end the search. Thus, it is clear that the magnitude of the voltage difference plays a crucial role in the multi-power peak scanning process, affecting both the search speed and the search accuracy.

[0108] In some embodiments, a method for calculating the difference voltage based on the first voltage can be determined based on experiments or experience.

[0109] In some embodiments, determining the difference voltage based on the first voltage specifically includes:

[0110] The number N of solar panels connected in series in the photovoltaic array is obtained. A differential voltage is determined based on a first voltage and the number N, with the differential voltage positively correlated with the first voltage and negatively correlated with the number N. The more solar panels connected in series in the photovoltaic array, the greater the photovoltaic output power, but also the greater the susceptibility to environmental influences and the more peak power points. Setting the differential voltage to be negatively correlated with the number N of solar panels—a larger number N results in a smaller differential voltage—increases the search range and search frequency, thereby improving the search speed and accuracy of the maximum power point.

[0111] In some embodiments, determining the difference voltage based on the first voltage specifically includes:

[0112] In the first control process, the power difference between the real-time target power of the air conditioner and the real-time output power of the photovoltaic is obtained. The difference voltage is determined based on the first voltage and the power difference, and the difference voltage is positively correlated with the first voltage and negatively correlated with the power difference.

[0113] In the second control process, the frequency difference between the real-time target frequency and the set frequency value is obtained, and the difference voltage is determined based on the first voltage and the frequency difference. The difference voltage is positively correlated with the first voltage and negatively correlated with the frequency difference. The set frequency value is determined based on the set frequency conditions.

[0114] The above method determines the differential voltage by using different parameters in different control processes, and can perform photovoltaic multi-power searches under different search ranges and search frequencies according to real-time operating conditions, which is beneficial to improving the search speed and search accuracy of the maximum power point.

[0115] In some other embodiments, determining the difference voltage based on the first voltage specifically includes:

[0116] In the first control process, the power difference between the real-time target power of the air conditioner and the real-time output power of the photovoltaic is obtained, and the number N of the photovoltaic array connected in series is also obtained. The difference voltage is determined based on the first voltage, the power difference and the number N, and the difference voltage is positively correlated with the first voltage, negatively correlated with the power difference and negatively correlated with the number N.

[0117] In the second control process, the frequency difference between the real-time target frequency and the set frequency value is obtained, and the number N of the photovoltaic array connected in series is also obtained. The difference voltage is determined based on the first voltage, the frequency difference, and the number N. The difference voltage is positively correlated with the first voltage, negatively correlated with the frequency difference, and negatively correlated with the number N. The set frequency value is determined based on the set frequency conditions.

[0118] The above method, combined with the number of series-connected solar panels, uses different parameters to determine the differential voltage in different control processes. It can perform photovoltaic multi-power searches under different search ranges and search frequencies according to real-time operating conditions, which is beneficial to improving the search speed and accuracy of the maximum power point.

[0119] Figure 3 shows a schematic diagram of an embodiment of the photovoltaic air conditioning control device of the present invention, which realizes the operation control of the photovoltaic air conditioner.

[0120] As shown in Figure 3, the control device of this embodiment includes structural units, the functions of the structural units, and the relationships between them, as detailed below:

[0121] The control device includes:

[0122] The real-time target frequency acquisition unit 31 is used to acquire the real-time target frequency of the photovoltaic air conditioner.

[0123] The real-time air conditioning target power acquisition unit 32 is used to acquire the real-time air conditioning target power of the photovoltaic air conditioner.

[0124] The real-time photovoltaic output power acquisition unit 33 is used to acquire the real-time photovoltaic output power of the photovoltaic array in the photovoltaic air conditioner.

[0125] The execution unit 34 is used to execute a first control process when the real-time target frequency acquired by the real-time target frequency acquisition unit 31 meets the set frequency conditions, and to execute a second control process when the real-time target frequency does not meet the set frequency conditions.

[0126] The first control process includes: when the real-time air conditioning target power acquired by the real-time air conditioning target power acquisition unit 32 is greater than the real-time photovoltaic output power acquired by the real-time photovoltaic output power acquisition unit 33, performing photovoltaic multi-power peak scanning to obtain the photovoltaic maximum power point, and adjusting the actual operating frequency of the photovoltaic air conditioner according to the photovoltaic maximum power point; when the real-time air conditioning target power is not greater than the real-time photovoltaic output power, controlling the photovoltaic air conditioner to operate according to the real-time target frequency;

[0127] The second control process includes: performing photovoltaic multi-power peak scanning to obtain the photovoltaic maximum power point, and adjusting the actual operating frequency of the photovoltaic air conditioner according to the photovoltaic maximum power point;

[0128] The frequency setting conditions include any one of the following: low frequency operation mode, less than the set frequency limit, or less than the set frequency range.

[0129] The photovoltaic air conditioning control device with the above structure runs the corresponding software program, performs the corresponding functions, and controls the photovoltaic air conditioning according to the process of the photovoltaic air conditioning control method embodiment shown in Figure 1 or Figure 2 and other embodiments, so as to achieve the technical effect corresponding to the method embodiment.

[0130] The photovoltaic air conditioning control device described in the above embodiment is applied to a photovoltaic air conditioner that has an air conditioning unit and a photovoltaic array to control the photovoltaic air conditioner and improve the stability of its operation.

[0131] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions claimed by the present invention.

Claims

1. A photovoltaic air conditioning control method, characterized in that, The method includes: Obtain the real-time target frequency of the photovoltaic air conditioner; When the real-time target frequency meets the set frequency condition, the following first control procedure is executed: Obtain the real-time target power of the photovoltaic air conditioner and the real-time photovoltaic output power of the photovoltaic array; When the real-time target power of the air conditioner is greater than the real-time photovoltaic output power, a photovoltaic multi-power peak scan is performed to obtain the photovoltaic maximum power point, and the actual operating frequency of the photovoltaic air conditioner is adjusted according to the photovoltaic maximum power point; when the real-time target power of the air conditioner is not greater than the real-time photovoltaic output power, the photovoltaic air conditioner is controlled to operate according to the real-time target frequency. When the real-time target frequency does not meet the set frequency condition, the following second control process is executed: Perform the photovoltaic multi-power peak scan to obtain the photovoltaic maximum power point, and adjust the actual operating frequency of the photovoltaic air conditioner according to the photovoltaic maximum power point; The set frequency conditions include any one of the following: low frequency operation mode, less than the set frequency limit, or less than the set frequency range.

2. The photovoltaic air conditioning control method according to claim 1, characterized in that, The photovoltaic multi-power peak scan is performed to obtain the photovoltaic maximum power point, specifically including: On the photovoltaic power-voltage curve, the operating point with the open-circuit voltage is taken as the initial search point. The search proceeds in the direction of decreasing voltage until the first peak power point is found. The first voltage and the first power corresponding to the first peak power point are recorded. The difference voltage is determined based on the first voltage; the difference voltage is less than the first voltage. The operating point where the voltage equals the voltage difference is used as the new search starting point to continue the search. The peak power point found in the subsequent search is recorded as the most recent peak power point, and the voltage and power corresponding to the most recent peak power point are recorded. The sum of the voltage corresponding to the most recent peak power point and the difference voltage is used as the voltage of the next search starting point; Determine whether the difference between the first voltage and the voltage of the next search starting point is less than the difference voltage; if not, take the operating point with a voltage equal to the voltage of the next search starting point as the new search starting point and continue searching; until the difference between the first voltage and the voltage of the next search starting point is less than the difference voltage, then stop searching; After stopping the search, the point with the highest power among all the peak power points found is determined as the photovoltaic maximum power point.

3. The photovoltaic air conditioning control method according to claim 2, characterized in that, Determining the difference voltage based on the first voltage specifically includes: The number N of the photovoltaic array connected in series is obtained, and the difference voltage is determined based on the first voltage and the number N. The difference voltage is positively correlated with the first voltage and negatively correlated with the number N.

4. The photovoltaic air conditioning control method according to claim 2, characterized in that, Determining the difference voltage based on the first voltage specifically includes: In the first control process, the power difference between the real-time air conditioning target power and the real-time photovoltaic output power is obtained, and the difference voltage is determined based on the first voltage and the power difference. The difference voltage is positively correlated with the first voltage and negatively correlated with the power difference. In the second control process, the frequency difference between the real-time target frequency and the set frequency value is obtained, and the difference voltage is determined based on the first voltage and the frequency difference. The difference voltage is positively correlated with the first voltage and negatively correlated with the frequency difference. The set frequency value is determined based on the set frequency condition.

5. The photovoltaic air conditioning control method according to claim 2, characterized in that, Determining the difference voltage based on the first voltage specifically includes: During the first control process, the power difference between the real-time target power of the air conditioner and the real-time photovoltaic output power is obtained, and the number N of the solar panels connected in series in the photovoltaic array is also obtained. The difference voltage is determined based on the first voltage, the power difference, and the number N. The difference voltage is positively correlated with the first voltage, negatively correlated with the power difference, and negatively correlated with the number N. During the second control process, the frequency difference between the real-time target frequency and the set frequency value is obtained, and the number N of the photovoltaic array connected in series is also obtained. The difference voltage is determined based on the first voltage, the frequency difference, and the number N. The difference voltage is positively correlated with the first voltage, negatively correlated with the frequency difference, and negatively correlated with the number N. The set frequency value is determined based on the set frequency condition.

6. The photovoltaic air conditioning control method according to any one of claims 1 to 5, characterized in that, The first control process further includes: When the real-time target power of the air conditioner is greater than the real-time output power of the photovoltaic system, the number of times the photovoltaic air conditioner operates at reduced frequency in real-time is also obtained. When the number of real-time frequency reduction operations is less than a preset threshold, the actual intermittent operation mode corresponding to the actual operating frequency is determined according to the correspondence between the operating frequency and the intermittent operation mode; the intermittent operation mode includes at least continuous operating time and downtime; The operation of the photovoltaic air conditioner is controlled according to the actual operating frequency and the actual intermittent operating mode.

7. The photovoltaic air conditioning control method according to claim 6, characterized in that, The continuous operating time in the intermittent operation mode is a variable value and is determined using the following formula: T = k1 × f + k2 × n; Where T is the continuous running time, f is the actual running frequency, n is the number of times the real-time frequency reduction operation is performed, k1 is a known coefficient greater than 0, and k2 is a known coefficient less than 0.

8. The photovoltaic air conditioning control method according to claim 6, characterized in that, The downtime in the intermittent operation mode is a variable value and is determined using the following formula: t = k3 × n; Where t is the downtime, n is the number of times the real-time frequency reduction operation is performed, and k3 is a known coefficient greater than 0.

9. A photovoltaic air conditioning control device, characterized in that, The device includes: Real-time target frequency acquisition unit, used to acquire the real-time target frequency of photovoltaic air conditioner; A real-time air conditioning target power acquisition unit is used to acquire the real-time air conditioning target power of the photovoltaic air conditioner. A real-time photovoltaic output power acquisition unit is used to acquire the real-time photovoltaic output power of the photovoltaic array in a photovoltaic air conditioner. An execution unit is configured to execute a first control process when the real-time target frequency meets the set frequency condition and to execute a second control process when the real-time target frequency does not meet the set frequency condition. The first control process includes: when the real-time air conditioner target power is greater than the real-time photovoltaic output power, performing photovoltaic multi-power peak scanning to obtain the photovoltaic maximum power point, and adjusting the actual operating frequency of the photovoltaic air conditioner according to the photovoltaic maximum power point; when the real-time air conditioner target power is not greater than the real-time photovoltaic output power, controlling the photovoltaic air conditioner to operate according to the real-time target frequency; The second control process includes: performing the photovoltaic multi-power peak scan to obtain the photovoltaic maximum power point, and adjusting the actual operating frequency of the photovoltaic air conditioner according to the photovoltaic maximum power point; The set frequency conditions include any one of the following: low frequency operation mode, less than the set frequency limit, or less than the set frequency range.

10. A photovoltaic air conditioner, comprising an air conditioner body and a photovoltaic array, characterized in that, The photovoltaic air conditioner also includes the photovoltaic air conditioner control device as described in claim 9.

Images