A photovoltaic charging control method, device and system

Abstract

The present application relates to photovoltaic charging technical field, mainly provide a kind of photovoltaic charging control method, device and system, applied to photovoltaic charging control system, by obtaining the photovoltaic input voltage of the photovoltaic input source, and when the photovoltaic input voltage is greater than preset threshold, start the energy storage inverter.Then the output voltage of the energy storage inverter is obtained, whether the output voltage is in the preset voltage range is detected, when the output voltage is not in the preset voltage range, the first duty cycle of the step-down circuit in the energy storage inverter is adjusted, to access the power load when the output voltage of the energy storage inverter is in the preset range, at this time, the output current of the energy storage inverter is adjusted to target current based on MPPT principle, and the output power of the energy storage inverter is maximum power when the energy storage inverter works with the target current, based on this, the power load can be powered with maximum output power.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic charging, and in particular to a photovoltaic charging control method, device and system. Background Technology

[0002] Energy storage inverters, as electronic devices capable of bidirectional conversion between grid power and battery power, are widely used in the field of photovoltaic charging technology. When a photovoltaic input source charges the energy storage inverter, the charging process is primarily controlled by a photovoltaic control system.

[0003] In existing technology, the maximum input voltage of the charging port of the energy storage inverter is 145V, while the photovoltaic input source is directly connected to the energy storage inverter. When the output voltage of the photovoltaic input source is too high, it may damage the energy storage inverter. Therefore, in order to ensure the normal operation of the energy storage inverter, it is necessary to control the output voltage of the photovoltaic input source. Summary of the Invention

[0004] This invention provides a photovoltaic charging control method, device, and system, aiming to solve the technical problem of low charging efficiency in existing photovoltaic charging control systems.

[0005] To solve the above-mentioned technical problems, one technical solution adopted in this invention is: providing a photovoltaic charging control method applied to a photovoltaic charging control system, wherein the photovoltaic charging control system includes multiple photovoltaic input ports and multiple energy storage inverters, each photovoltaic input port is connected to one of the energy storage inverters, the photovoltaic input ports are used to connect to a photovoltaic input source, and the method is used to control one of the energy storage inverters, the method comprising:

[0006] Obtain the photovoltaic input voltage of the photovoltaic input source;

[0007] When the photovoltaic input voltage is greater than a preset threshold, the energy storage inverter is started, and the output voltage of the energy storage inverter is obtained; it is then detected whether the output voltage is within a preset voltage range.

[0008] When the output voltage is not within the preset voltage range, the first duty cycle of the step-down circuit in the energy storage inverter is adjusted to bring the output voltage within the preset voltage range, and the electrical load is connected to the energy storage inverter.

[0009] Based on the MPPT principle, the output current of the energy storage inverter is adjusted so that the output current is the target current and supplies power to the electrical load.

[0010] Optionally, the step of adjusting the first duty cycle of the buck circuit in the energy storage inverter when the output voltage is not within the preset voltage range includes:

[0011] When the output voltage is not within the preset voltage range, if the output voltage is less than the first preset voltage, the first duty cycle of the buck circuit is increased according to the preset increase until the output voltage is within the preset voltage range.

[0012] If the output voltage is greater than the second preset voltage, the first duty cycle of the buck circuit is reduced according to the preset reduction rate until the output voltage is within the preset voltage range, wherein the first preset voltage is less than the second preset voltage.

[0013] Optionally, the step of adjusting the first duty cycle of the buck circuit in the energy storage inverter when the output voltage is not within the preset voltage range further includes:

[0014] If the output voltage is greater than the third preset voltage, the energy storage inverter will be turned off.

[0015] Optionally, the step of adjusting the output current of the energy storage inverter based on the MPPT principle to make the output current the target current includes:

[0016] Obtain the current output current of the energy storage inverter and record the second duty cycle input to the buck circuit of the energy storage inverter at this time;

[0017] Use the current output current as the target current;

[0018] The second duty cycle of the buck circuit of the energy storage inverter is increased by a preset amount, and the first current output by the energy storage inverter is obtained.

[0019] Determine whether the first current is less than the target current;

[0020] If the first current is greater than or equal to the target current, return to the step of obtaining the current output current of the energy storage inverter, and record the first current as the current output current;

[0021] If the first current is less than the target current, the second duty cycle of the buck circuit of the energy storage inverter is reduced by a preset amount, and the second current output by the energy storage inverter is obtained; and it is determined whether the second current is less than the target current.

[0022] If the second current is greater than or equal to the target current, then the second current is taken as the target current, and the process returns to the step of reducing the second duty cycle of the buck circuit of the energy storage inverter by a preset amount.

[0023] If the second current is less than the target current, then the second duty cycle is output, and the process returns to the step of obtaining the current output current of the energy storage inverter.

[0024] Optionally, the step of outputting the second duty cycle and returning to obtain the current output current of the energy storage inverter includes:

[0025] Output the second duty cycle and obtain the photovoltaic input voltage corresponding to the output of the second duty cycle;

[0026] Real-time detection of the current photovoltaic input voltage, and determination of whether the difference between the current photovoltaic input voltage and the corresponding photovoltaic input voltage is within a preset range;

[0027] If so, then continue outputting the second duty cycle;

[0028] If not, return to the step of obtaining the current output current of the energy storage inverter.

[0029] Optionally, the step of outputting a second duty cycle and returning to obtain the current output current of the energy storage inverter further includes:

[0030] Obtain the current limiting threshold of the energy storage inverter;

[0031] Based on the feedback adjustment method, the third duty cycle corresponding to the current limiting threshold is obtained, and it is determined whether the second duty cycle is greater than the third duty cycle;

[0032] If so, output the third duty cycle and return to the step of obtaining the current output current of the energy storage inverter;

[0033] If not, output the second duty cycle and return to the step of obtaining the current output current of the energy storage inverter.

[0034] Optionally, the step of adjusting the output current of the energy storage inverter based on the MPPT principle to make the output current the target current includes:

[0035] After the energy storage inverter starts charging, the third current corresponding to the first charging of the energy storage inverter is obtained, and the third current is used as the target current.

[0036] Obtain the current output current and third duty cycle of the energy storage inverter;

[0037] Determine whether the current output current is less than the target current;

[0038] If the current output current is greater than or equal to the target current, then the current output current is taken as the target current, and the third duty cycle of the energy storage inverter is increased by a preset magnitude, and the process returns to the step of obtaining the current output current of the energy storage inverter.

[0039] If the current output current is less than the target current, the current output current is increased by a preset bias amount, and it is determined whether the increased current output current is less than the target current.

[0040] If the increased current output current is greater than or equal to the target current, then the third duty cycle of the energy storage inverter is increased by a preset magnitude, and the process returns to the step of obtaining the current output current of the energy storage inverter.

[0041] If the increased current output current is less than the target current, then the third duty cycle of the energy storage inverter is reduced by a preset magnitude, and the process returns to the step of obtaining the current output current of the energy storage inverter.

[0042] Optionally, the method further includes:

[0043] Obtain the temperature of the photovoltaic charging control system;

[0044] When the temperature is higher than the first preset temperature, the duty cycle of the photovoltaic charging control system is adjusted to reduce the temperature of the photovoltaic charging control system.

[0045] When the temperature is lower than the second preset temperature, the duty cycle is adjusted again so that the output current of the photovoltaic charging control system is the target current.

[0046] To solve the above-mentioned technical problems, another technical solution adopted in the embodiments of the present invention is: providing a photovoltaic charging control device, the photovoltaic charging control device being used to control one of the energy storage inverters, including:

[0047] The acquisition module is used to acquire the photovoltaic input voltage of the photovoltaic input source;

[0048] The detection module is used to start the energy storage inverter when the photovoltaic input voltage is greater than a preset threshold, and to obtain the output voltage of the energy storage inverter; and to detect whether the output voltage is within a preset voltage range.

[0049] The first adjustment module is used to adjust the first duty cycle of the step-down circuit in the energy storage inverter when the output voltage is not within the preset voltage range, so as to adjust the output voltage to the preset voltage range and connect the electrical load to the energy storage inverter.

[0050] The second adjustment module is used to adjust the output current of the energy storage inverter based on the MPPT principle, so that the output current is the target current and supplies power to the electrical load.

[0051] To solve the above-mentioned technical problems, another technical solution adopted in the embodiments of the present invention is: to provide a photovoltaic charging control system, the photovoltaic charging control system comprising:

[0052] At least one photovoltaic input source;

[0053] Multiple photovoltaic input ports connected to the at least one photovoltaic input source;

[0054] Energy storage inverters connected to the plurality of photovoltaic input ports; and

[0055] Controller;

[0056] The controller includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the photovoltaic charging control method as described above.

[0057] Unlike related technologies, this invention provides a photovoltaic charging control method, device, and system applied to a photovoltaic charging control system. It primarily acquires the photovoltaic input voltage of the photovoltaic input source and, when the photovoltaic input voltage exceeds a preset threshold, activates the energy storage inverter. Then, it acquires the output voltage of the energy storage inverter and detects whether the output voltage is within a preset voltage range. If the output voltage is outside the preset voltage range, it adjusts the first duty cycle of the step-down circuit in the energy storage inverter to connect the electrical load when the output voltage of the energy storage inverter is within the preset range. At this time, based on the MPPT principle, the output current of the energy storage inverter is adjusted to a target current. When the energy storage inverter operates at the target current, its output power is at its maximum. Therefore, the maximum output power can be used to supply power to the electrical load. Attached Figure Description

[0058] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0059] Figure 1 This is a structural block diagram of a photovoltaic charging control system provided in an embodiment of the present invention;

[0060] Figure 2This is a structural block diagram of a controller provided in an embodiment of the present invention;

[0061] Figure 3 This is a flowchart of a photovoltaic charging control method provided in an embodiment of the present invention;

[0062] Figure 4 This is a flowchart of adjusting the output voltage of the energy storage inverter provided in an embodiment of the present invention;

[0063] Figure 5 This is a flowchart of MPPT-based adjustment provided in an embodiment of the present invention;

[0064] Figure 6 This is a flowchart of MPPT-based adjustment provided in another embodiment of the present invention;

[0065] Figure 7 This is a structural block diagram of a photovoltaic charging control device provided in an embodiment of the present invention. Detailed Implementation

[0066] 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. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0067] It should be noted that, unless otherwise specified, the various features in the embodiments of the present invention can be combined with each other, and all are within the protection scope of the present invention. Furthermore, although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different module division or in a different order than that shown in the device schematic diagram or the flowchart.

[0068] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0069] Please see Figure 1 , Figure 1 This is a structural block diagram of a photovoltaic charging control system provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the photovoltaic charging control system 100 includes at least one photovoltaic input source 11 and multiple photovoltaic input ports 12 connected to the at least one photovoltaic input source 11. The multiple photovoltaic input ports 12 are also connected to multiple energy storage inverters 13, wherein each photovoltaic input port 12 is connected to one energy storage inverter 13. Figure 1 Taking a photovoltaic input source 11, a photovoltaic input port 12, and an energy storage inverter 13 as an example, the photovoltaic charging control system 100 also includes a controller 14, which is connected to the energy storage inverter 13 and the photovoltaic input source 11 respectively.

[0070] Specifically, during the operation of the photovoltaic charging control system 100, the controller 14 monitors the photovoltaic input voltage of the photovoltaic input source 11 in real time. When the photovoltaic input voltage exceeds a preset threshold, the energy storage inverter 13 is activated. At this time, the voltage in the photovoltaic input source 11 is input to the energy storage inverter 13 through the photovoltaic input port 12. After the energy storage inverter 13 is activated, the controller 14 monitors the output voltage of the energy storage inverter 13 in real time and determines whether the output voltage of the energy storage inverter 13 is within a preset range. Furthermore, the energy storage inverter 13 includes a step-down circuit 131. When the output voltage is not within the preset range, the controller 14 starts adjusting the duty cycle of the step-down circuit 131 to bring the output voltage of the energy storage inverter 13 within the preset range. Then, the energy storage inverter 13 is connected to the electrical load 15 to supply power to the electrical load 15. By controlling the output voltage of the energy storage inverter 13 within a preset range, damage to the electrical load 15 caused by high voltage can be avoided.

[0071] Please see Figure 2 , Figure 2 This is a structural block diagram of a controller provided in an embodiment of the present invention, such as... Figure 2 As shown, the controller 14 includes at least one processor 141. Figure 2 Taking a processor 141 as an example; the at least one processor 141 is communicatively connected to a memory 142. Figure 2 Taking the example of a connection between China and Israel via a bus.

[0072] The memory 142 stores instructions that can be executed by the at least one processor 141, which are executed by the at least one processor 141 to enable the at least one processor 141 to perform the following photovoltaic charging control method.

[0073] The memory 142, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules, such as the program instructions / modules corresponding to the photovoltaic charging control method in the embodiments of the present invention. The processor 141 executes various functional applications and data processing of the controller 14 by running the non-volatile software programs, instructions, and modules stored in the memory 142, thereby implementing the photovoltaic charging control method in the following method embodiments.

[0074] Memory 142 may include a program storage area and a data storage area, wherein the program storage area may store the operating system and application programs required for at least one function. Furthermore, memory 142 may include high-speed random access memory and may also include non-volatile memory. For example, it may include at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some embodiments, memory 142 may optionally include memory remotely located relative to processor 141.

[0075] The one or more modules are stored in the memory 142, and when executed by the one or more processors 141, they execute the photovoltaic charging control method in any of the following method embodiments.

[0076] The controller described above can execute the methods provided in the embodiments of the present invention and has corresponding functional modules for executing the methods. Technical details not described in detail in this embodiment can be found in the methods provided in the embodiments of the present invention.

[0077] Please see Figure 3 , Figure 3 This is a flowchart of a photovoltaic charging control method provided in an embodiment of the present invention, such as... Figure 3 As shown, the method includes:

[0078] S1. Obtain the photovoltaic input voltage of the photovoltaic input source.

[0079] Specifically, when the photovoltaic input source is connected to the energy storage inverter, the input voltage of the photovoltaic input source is obtained, wherein the input voltage of the photovoltaic input source is obtained based on the solar photovoltaic panel.

[0080] S2. When the photovoltaic input voltage is greater than a preset threshold, start the energy storage inverter and obtain the output voltage of the energy storage inverter; detect whether the output voltage is within the preset voltage range.

[0081] Specifically, after the energy storage inverter starts up, the controller also inputs an initial control signal to the buck circuit in the energy storage inverter to obtain the output voltage of the energy storage inverter. The initial control signal can be determined based on the photovoltaic input voltage or historical records. After obtaining the output voltage of the energy storage inverter, it is necessary to check whether the output voltage is within a preset voltage range. If the output voltage is within the preset voltage range, the electrical load is connected to the energy storage inverter. The preset voltage range is obtained empirically; by setting an appropriate voltage range, damage to the electrical load due to excessive output voltage can be avoided after the energy storage inverter is connected. Furthermore, by setting a preset threshold, the output of the energy storage inverter can be ensured to be within the preset voltage range more quickly, thus saving adjustment time. Optionally, the preset threshold is 120V, and the preset voltage range is 65–125V.

[0082] S3. When the output voltage is not within the preset voltage range, adjust the first duty cycle of the step-down circuit in the energy storage inverter to adjust the output voltage to the preset voltage range, and connect the electrical load to the energy storage inverter.

[0083] When the energy storage inverter is unloaded, the output voltage of the energy storage inverter is a floating voltage. At this time, the controller adjusts the first duty cycle of the buck circuit in the energy storage inverter to ensure that the output voltage is within the preset voltage range.

[0084] For details, please refer to Figure 4 , Figure 4 This is a flowchart of adjusting the output voltage of the energy storage inverter provided in an embodiment of the present invention, including:

[0085] S31, Obtain the output voltage;

[0086] When the output voltage exceeds the preset threshold, the output voltage of the energy storage inverter is acquired in real time.

[0087] S32. Is the output voltage less than the first preset voltage?

[0088] If yes, proceed to step S33; otherwise, proceed to step S34.

[0089] S33. Increase the first duty cycle according to the preset increase, and return to step S31;

[0090] When the output voltage is less than a first preset voltage, the first duty cycle of the buck circuit is gradually increased by a preset increment, and then the process returns to step S31. The preset increment is obtained empirically; increasing the first duty cycle by the preset increment allows the output voltage to rise rapidly. Optionally, the preset increment can be a 5% increase in the duty cycle every 7.5 ms.

[0091] S34. Is the output voltage greater than the second preset voltage?

[0092] If yes, proceed to step S35; otherwise, proceed to step S36.

[0093] Wherein, the first preset voltage is less than the second preset voltage.

[0094] S35. Reduce the first duty cycle according to the preset reduction rate;

[0095] When the output voltage is greater than the second preset voltage, the first duty cycle of the buck circuit is reduced according to a preset reduction rate, and then the process returns to step S31. The preset reduction rate is obtained empirically, and the preset increase rate is greater than the preset reduction rate. Optionally, the preset reduction rate can be a decrease of 0.03% of the duty cycle every 7.5ms.

[0096] S36. Connect the electrical load to the energy storage inverter.

[0097] When the output voltage of the energy storage inverter is greater than the first preset voltage and less than the second preset voltage, it proves that the output voltage of the energy storage inverter is within the preset voltage range. At this time, the electrical load can be connected to the energy storage inverter to supply power to the electrical load. It should be noted that in this invention, before the load is connected to the energy storage inverter, the output voltage of the energy storage inverter is first adjusted to the preset range to avoid damage to the load due to excessively high voltage, and also to avoid power loss of the load due to insufficient photovoltaic voltage after the photovoltaic system wakes up the load.

[0098] In some embodiments, when the output voltage exceeds a third preset voltage, the energy storage inverter may be in a high-voltage state, potentially posing a safety hazard. The third preset voltage is greater than the second preset voltage. In this case, the first duty cycle of the step-down circuit in the energy storage inverter can be cleared to shut down the inverter's drive, thereby rapidly reducing the output voltage and improving the inverter's safety.

[0099] S4. Based on the MPPT principle, adjust the output current of the energy storage inverter so that the output current is the target current and supplies power to the electrical load.

[0100] Specifically, the MPPT (Maximum Power Point Tracking) can detect the voltage generated by the solar photovoltaic panel in real time and track the highest voltage and current values, enabling the energy storage inverter to supply power to the electrical load at maximum power output. Since the output voltage of the energy storage inverter is constant, the higher the output current, the higher the output power of the energy storage inverter. Therefore, the output current of the energy storage inverter can be adjusted by regulating the duty cycle of the step-down circuit in the energy storage inverter, thereby maximizing the output power of the energy storage inverter.

[0101] Please participate Figure 5 , Figure 5 This is a flowchart based on MPPT adjustment provided in an embodiment of the present invention, including:

[0102] S410. Obtain the current output current of the energy storage inverter and record the second duty cycle input to the buck circuit of the energy storage inverter at this time.

[0103] The second duty cycle is obtained based on the first duty cycle. Specifically, when the buck circuit input of the energy storage inverter is the first duty cycle, the output voltage of the energy storage inverter is not within the preset voltage range. In this case, by adjusting the first duty cycle input to the buck circuit of the energy storage inverter to the second duty cycle, the output voltage of the energy storage inverter is brought within the preset voltage range, and then the current output current of the energy storage inverter operating at the second duty cycle is obtained. In some embodiments, when the energy storage inverter starts up and its output voltage is within the preset voltage range, the second duty cycle is equal to the first duty cycle.

[0104] S411. Use the current output current as the target current;

[0105] Specifically, after obtaining the current output current based on the second duty cycle, the current output current is set as the target current, where the target current refers to the maximum output current of the energy storage inverter.

[0106] S412. Increase the second duty cycle of the buck circuit of the energy storage inverter by a preset amount, and obtain the first current output by the energy storage inverter;

[0107] Specifically, when the second duty cycle changes, the output current of the energy storage inverter also changes accordingly. By increasing the second duty cycle by a preset amount, the current output current of the energy storage inverter can be controlled to change according to a certain pattern. At this time, the first current corresponding to the adjusted second duty cycle is obtained.

[0108] S413. Determine whether the first current is less than the target current;

[0109] If not, proceed to step S414; if yes, proceed to step S415.

[0110] S414. Record the first current as the current output current and return to step S410;

[0111] Specifically, if the first current is greater than the target current, the first current is recorded as the current output current, and the second duty cycle is updated to the duty cycle corresponding to the first current, i.e., the adjusted second duty cycle. Specifically, by determining whether the current output current corresponding to the second duty cycle, which is increased by a preset amount, has increased, if it has increased, the second duty cycle is gradually increased to obtain the target current of the energy storage inverter.

[0112] S415. Reduce the second duty cycle of the buck circuit of the energy storage inverter by a preset amount, and obtain the second current output by the energy storage inverter;

[0113] If the current output current decreases instead of increasing the second duty cycle by a preset amount, then the second duty cycle is decreased by a preset amount to determine whether the current output current increases when the second duty cycle is decreased.

[0114] S416. Determine whether the second current is less than the target current;

[0115] If not, proceed to step S417; if yes, proceed to step S418.

[0116] S417. Take the second current as the target current and return to step S415;

[0117] If the second duty cycle is reduced by a preset amount, the current output current will increase accordingly. Then, step S415 can be repeated to gradually reduce the second duty cycle until the current output current is the target current.

[0118] S418. Output the second duty cycle and execute step S410.

[0119] Since the input voltage of the photovoltaic input source changes with the environment, and the duty cycle corresponding to the maximum output power also changes when the input voltage changes, it is necessary to detect the input voltage of the photovoltaic input source in real time so as to adjust the second duty cycle of the buck circuit in the energy storage inverter in real time according to the input voltage, thereby ensuring that the energy storage inverter outputs the maximum power.

[0120] Specifically, when the current output current decreases regardless of whether the second duty cycle is increased or decreased by a preset amount, the current second duty cycle is acquired, along with the photovoltaic input voltage corresponding to that duty cycle. Then, the current photovoltaic input voltage of the photovoltaic input source is monitored in real time, and the difference between the photovoltaic input voltage corresponding to the second duty cycle and the current photovoltaic input voltage is acquired. It is determined whether the difference is within a preset range. If it is, the second duty cycle is continuously output; otherwise, the process returns to step S410 to reacquire the current output current of the energy storage inverter. By determining whether the change in the photovoltaic input source voltage exceeds a preset range to decide whether to reacquire the current output current of the energy storage inverter, the step of frequently recalculating the current output current is avoided, thereby reducing the computational load on the controller and extending its service life. The preset range is obtained based on multiple experiments. By using this preset range, the error between the output power and the maximum output power of the energy storage inverter can be reduced while simultaneously reducing the computational load on the controller.

[0121] In some embodiments, when the current output current of the energy storage inverter continues to increase, it may exceed the current carrying capacity of the photovoltaic charging control system. If the current output current continues to increase, it will damage the devices in the photovoltaic charging control system. Therefore, it is necessary to set a current limiting threshold for the output current of the energy storage inverter based on the carrying capacity of the devices in the photovoltaic charging control system. After obtaining the current limiting threshold of the energy storage inverter, a third duty cycle corresponding to the current limiting threshold is calculated based on a feedback adjustment method. Here, the feedback adjustment method refers to adjusting the operation of the system based on its own operating effect. Then, the magnitude of the third duty cycle and the second duty cycle is determined. If the third duty cycle is less than the second duty cycle, it proves that when the energy storage inverter operates at the second duty cycle, the current output current will be greater than the current limiting threshold. Therefore, when the third duty cycle is less than the second duty cycle, the buck circuit in the energy storage inverter is controlled to operate at the third duty cycle, and the process returns to step S410 to re-obtain the current output current of the energy storage inverter. If the third duty cycle is greater than the second duty cycle, it proves that the current output current has not exceeded the current limiting threshold. At this time, the buck circuit in the energy storage inverter is controlled to work at the second duty cycle, and the process returns to step S410 to obtain the current output current of the energy storage inverter again.

[0122] Please see Figure 6 , Figure 6 This is a flowchart based on MPPT adjustment provided in another embodiment of the present invention, including:

[0123] S420: After the energy storage inverter starts charging, obtain the third current corresponding to the first charging of the energy storage inverter, and use the third current as the target current.

[0124] Specifically, when the energy storage inverter starts charging the electrical load, and when the energy storage inverter is charging for the first time, the third current corresponding to the first charging is obtained. At this time, since the energy storage inverter is charging for the first time, the third current is the maximum output current, that is, the third current is the target current. When the energy storage inverter is not charging, the third duty cycle of the buck circuit in the energy storage inverter needs to be cleared to shut down the output.

[0125] S421. Obtain the current output current and third duty cycle of the energy storage inverter;

[0126] When the energy storage inverter is not being charged for the first time, obtain the current output current and the third duty cycle of the energy storage inverter.

[0127] S422. Determine whether the current output current is less than the target current;

[0128] If not, proceed to step S423; if yes, proceed to step S424.

[0129] S423. Take the current output current as the target current and execute step S426;

[0130] When the current output current is greater than the target current, the current output current is considered to be the maximum output current. In this case, the target current needs to be updated to the current output current so that the output power of the energy storage inverter is the maximum power.

[0131] S424. Increase the current output current according to the preset bias amount;

[0132] The preset bias value was obtained through multiple experiments. By setting this preset bias value, the probability of misjudgment is reduced. In other words, when the current output current is detected to be less than the target current, the preset bias value is added to the current output current to avoid misjudgment due to fluctuations in the current output current. It should be noted that the preset bias value is much smaller than the current output current.

[0133] S425. Determine whether the increased current output current is less than the target current;

[0134] If not, proceed to step S426; if yes, proceed to step S427.

[0135] S426. Increase the third duty cycle of the energy storage inverter by a preset amplitude, and return to step S420;

[0136] S427. Reduce the third duty cycle of the energy storage inverter by a preset amplitude, and return to step S420.

[0137] Specifically, the duty cycle of the buck circuit in the energy storage inverter is adjusted in real time by obtaining the comparison result between the current output current and the target current, so as to control the output power of the energy storage inverter to the maximum power.

[0138] In some embodiments, during the operation of the photovoltaic charging control system, it is also necessary to monitor the temperature of the photovoltaic charging control system in real time to avoid safety hazards caused by excessively high temperatures. Specifically, the temperature of the photovoltaic charging control system is first obtained, and it is determined whether the temperature is greater than a first preset temperature. If it is greater, the duty cycle of the photovoltaic charging control system is adjusted to reduce the temperature. When the temperature is lower than a second preset temperature, the duty cycle is adjusted again to make the output current of the photovoltaic charging control system the target current. Specifically, when the temperature of the photovoltaic charging control system is higher than the first preset temperature, the output current is reduced by adjusting the duty cycle based on high-temperature current reduction, thereby lowering the temperature of the photovoltaic charging control system. When the temperature is lower than the second preset temperature, the duty cycle is adjusted to make the output current of the photovoltaic charging control system the target current, thereby achieving the goal of maximum output power. It should be noted that the first and second preset temperatures are obtained based on multiple experiments; for example, the first preset temperature is 80 degrees Celsius, and the second preset temperature is 65 degrees Celsius.

[0139] In some embodiments, when the photovoltaic charging control system operates with multiple photovoltaic input sources in parallel, for example, a first photovoltaic input source and a second photovoltaic input source operate in parallel, the system acquires the input voltages of the first and second photovoltaic input sources within a preset time period, calculates the difference between the input voltages, and then determines whether the difference is less than a preset difference. If so, the system acquires the fourth duty cycle corresponding to the first photovoltaic input source and controls the duty cycle of the step-down circuit in the energy storage inverter corresponding to the second photovoltaic input source to be the fourth duty cycle, so that the second photovoltaic input source follows the first photovoltaic input source, thereby achieving the effect of current sharing between the two inputs. If not, individual control is performed. It should be noted that as energy storage power sources continue to develop, their capacities are becoming increasingly larger. To improve the charging efficiency of energy storage power sources, a single energy storage power source is usually connected to multiple photovoltaic input sources located adjacent to each other, with the photovoltaic input sources receiving essentially the same light intensity. Therefore, an energy storage inverter is regulated according to the photovoltaic charging control method. For ease of understanding, the energy storage inverter regulated by the photovoltaic charging control method is referred to as the first energy storage inverter. As for the regulation strategy of other energy storage inverters, by judging that the voltage difference between the voltage of other photovoltaic inputs and the voltage of the regulated photovoltaic input source is within a preset difference range, the other energy storage inverters are regulated according to the control signal output by the first energy storage inverter. This eliminates the need for other energy storage inverters to perform recalculation, thereby reducing the amount of memory used.

[0140] This invention provides a photovoltaic charging control method applied to a photovoltaic charging control system. It primarily involves acquiring the photovoltaic input voltage of the photovoltaic input source and activating the energy storage inverter when the photovoltaic input voltage exceeds a preset threshold. Then, it acquires the output voltage of the energy storage inverter and checks whether the output voltage is within a preset voltage range. If the output voltage is outside the preset voltage range, it adjusts the first duty cycle of the step-down circuit in the energy storage inverter to connect the electrical load when the output voltage of the energy storage inverter is within the preset range. At this time, based on the MPPT principle, the output current of the energy storage inverter is adjusted to a target current. When the energy storage inverter operates at the target current, its output power is at its maximum. Therefore, the load can be powered at its maximum output power.

[0141] Please see Figure 7 , Figure 7 This is a structural block diagram of a photovoltaic charging control device provided in an embodiment of the present invention, as shown below. Figure 7 As shown, the photovoltaic charging control device 400 includes an acquisition module 41, a detection module 42, a first adjustment module 43, and a second adjustment module 44.

[0142] The acquisition module 41 is used to acquire the photovoltaic input voltage of the photovoltaic input source.

[0143] The detection module 42 is used to start the energy storage inverter and obtain the output voltage of the energy storage inverter when the photovoltaic input voltage is greater than a preset threshold; and to detect whether the output voltage is within a preset voltage range.

[0144] The first adjustment module 43 is used to adjust the first duty cycle of the step-down circuit in the energy storage inverter when the output voltage is not within the preset voltage range, so as to adjust the output voltage to the preset voltage range and connect the electrical load to the energy storage inverter.

[0145] The second adjustment module 44 is used to adjust the output current of the energy storage inverter based on the MPPT principle, so that the output current is the target current and supplies power to the electrical load.

[0146] It should be noted that the above-described photovoltaic charging control device can execute the photovoltaic charging control method provided in the embodiments of the present invention, and has the corresponding functional modules and beneficial effects of the method. Technical details not described in detail in the embodiments of the photovoltaic charging control device can be found in the photovoltaic charging control method provided in the embodiments of the present invention.

[0147] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented using software and a general-purpose hardware platform, or of course, using hardware. Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0148] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; under the concept of the present invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the present invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A photovoltaic charging control method applied to a photovoltaic charging control system, characterized in that, The photovoltaic charging control system includes multiple photovoltaic input ports and multiple energy storage inverters. Each photovoltaic input port is connected to one of the energy storage inverters. The photovoltaic input ports are used to connect to a photovoltaic input source. The method is used to control one of the energy storage inverters. The method includes: Obtain the photovoltaic input voltage of the photovoltaic input source; When the photovoltaic input voltage is greater than a preset threshold, the energy storage inverter is started, and the output voltage of the energy storage inverter is obtained; it is then detected whether the output voltage is within a preset voltage range. When the output voltage is not within the preset voltage range, the first duty cycle of the step-down circuit in the energy storage inverter is adjusted to bring the output voltage within the preset voltage range, and the electrical load is connected to the energy storage inverter. Based on the MPPT principle, the output current of the energy storage inverter is adjusted so that the output current is the target current and supplies power to the electrical load. The step of adjusting the output current of the energy storage inverter based on the MPPT principle to make the output current the target current includes: Obtain the current output current of the energy storage inverter and record the second duty cycle input to the buck circuit of the energy storage inverter at this time; Use the current output current as the target current; The second duty cycle of the buck circuit of the energy storage inverter is increased by a preset amount, and the first current output by the energy storage inverter is obtained. Determine whether the first current is less than the target current; If the first current is greater than or equal to the target current, return to the step of obtaining the current output current of the energy storage inverter, and record the first current as the current output current; If the first current is less than the target current, the second duty cycle of the buck circuit of the energy storage inverter is reduced by a preset amount, and the second current output by the energy storage inverter is obtained; and it is determined whether the second current is less than the target current. If the second current is greater than or equal to the target current, then the second current is taken as the target current, and the process returns to the step of reducing the second duty cycle of the buck circuit of the energy storage inverter by a preset amount. If the second current is less than the target current, then the second duty cycle is output, and the process returns to the step of obtaining the current output current of the energy storage inverter. The step of outputting the second duty cycle and returning to obtain the current output current of the energy storage inverter includes: Output the second duty cycle and obtain the photovoltaic input voltage corresponding to the output of the second duty cycle; Real-time detection of the current photovoltaic input voltage, and determination of whether the difference between the current photovoltaic input voltage and the corresponding photovoltaic input voltage is within a preset range; If so, then continue outputting the second duty cycle; If not, return to the step of obtaining the current output current of the energy storage inverter.

2. The photovoltaic charging control method of claim 1, wherein, The step of adjusting the first duty cycle of the buck circuit in the energy storage inverter when the output voltage is not within the preset voltage range includes: When the output voltage is not within the preset voltage range, if the output voltage is less than the first preset voltage, the first duty cycle of the buck circuit is increased according to the preset increase until the output voltage is within the preset voltage range. If the output voltage is greater than the second preset voltage, the first duty cycle of the buck circuit is reduced according to the preset reduction rate until the output voltage is within the preset voltage range, wherein the first preset voltage is less than the second preset voltage.

3. The photovoltaic charging control method according to claim 2, characterized in that, The step of adjusting the first duty cycle of the buck circuit in the energy storage inverter when the output voltage is not within the preset voltage range further includes: If the output voltage is greater than the third preset voltage, the energy storage inverter will be turned off.

4. The photovoltaic charging control method according to claim 1, characterized in that, The step of outputting the second duty cycle and returning to obtain the current output current of the energy storage inverter further includes: Obtain the current limiting threshold of the energy storage inverter; Based on the feedback adjustment method, the third duty cycle corresponding to the current limiting threshold is obtained, and it is determined whether the second duty cycle is greater than the third duty cycle; If so, output the third duty cycle and return to the step of obtaining the current output current of the energy storage inverter; If not, output the second duty cycle and return to the step of obtaining the current output current of the energy storage inverter.

5. The photovoltaic charging control method according to claim 1, characterized in that, The step of adjusting the output current of the energy storage inverter based on the MPPT principle to make the output current the target current includes: After the energy storage inverter starts charging, the third current corresponding to the first charging of the energy storage inverter is obtained, and the third current is used as the target current. Obtain the current output current and third duty cycle of the energy storage inverter; Determine whether the current output current is less than the target current; If the current output current is greater than or equal to the target current, then the current output current is taken as the target current, and the third duty cycle of the energy storage inverter is increased by a preset magnitude, and the process returns to the step of obtaining the current output current of the energy storage inverter. If the current output current is less than the target current, the current output current is increased by a preset bias amount, and it is determined whether the increased current output current is less than the target current. If the increased current output current is greater than or equal to the target current, then the third duty cycle of the energy storage inverter is increased by a preset magnitude, and the process returns to the step of obtaining the current output current of the energy storage inverter. If the increased current output current is less than the target current, then the third duty cycle of the energy storage inverter is reduced by a preset magnitude, and the process returns to the step of obtaining the current output current of the energy storage inverter.

6. The method according to any one of claims 1 to 5, characterized in that, The method further includes: Obtain the temperature of the photovoltaic charging control system; When the temperature is higher than the first preset temperature, the duty cycle of the photovoltaic charging control system is adjusted to reduce the temperature of the photovoltaic charging control system. When the temperature is lower than the second preset temperature, the duty cycle is adjusted again so that the output current of the photovoltaic charging control system is the target current.

7. A photovoltaic charging control device, characterized in that, For executing the photovoltaic charging control method as described in any one of claims 1-6, the photovoltaic charging control device is used to control an energy storage inverter, comprising: The acquisition module is used to acquire the photovoltaic input voltage of the photovoltaic input source; The detection module is used to start the energy storage inverter when the photovoltaic input voltage is greater than a preset threshold, and to obtain the output voltage of the energy storage inverter; and to detect whether the output voltage is within a preset voltage range. The first adjustment module is used to adjust the first duty cycle of the step-down circuit in the energy storage inverter when the output voltage is not within the preset voltage range, so as to adjust the output voltage to the preset voltage range and connect the electrical load to the energy storage inverter. The second adjustment module is used to adjust the output current of the energy storage inverter based on the MPPT principle, so that the output current is the target current and supplies power to the electrical load.

8. A photovoltaic charging control system, characterized in that, The photovoltaic charging control system includes: At least one photovoltaic input source; Multiple photovoltaic input ports connected to the at least one photovoltaic input source; A plurality of energy storage inverters are connected to the plurality of photovoltaic input ports, wherein each energy storage inverter includes at least one buck circuit; and Controller; The controller includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the photovoltaic charging control method according to any one of claims 1 to 6.

Images