Solar power generation system and current sharing control method of parallel solar controller of solar power generation system

Abstract

The invention provides a solar power generation system and a current sharing control method of a parallel solar controller of the solar power generation system, in the current sharing process, state parameters and identity information of all solar controllers in the solar power generation system are obtained, and the state parameters comprise a target voltage, a charging stage and a charging current. Based on the identity information, the control role of each solar controller is determined, and the control role comprises a master controller and a slave controller. And under the condition that the execution controller is the slave controller, the target voltage and the charging stage on the master controller are followed. After following, according to the charging current of all the solar controllers in the system, the target voltage of the execution controller is subjected to cyclic stepping adjustment, so that the current-sharing control of the solar controllers connected in parallel in the solar power generation system is realized, the communication among the controllers is realized by using a serial communication protocol, the data sharing speed is increased, and the data sharing efficiency is improved. Current sharing is achieved by adjusting the target voltage in a stepping mode, and the accuracy of current sharing is improved.

Description

Technical Field

[0001] The present application relates to the field of solar power generation, and in particular to a solar power generation system and a current sharing control method of a parallel solar controller thereof. Background Art

[0002] With the continuous expansion of the installed capacity of solar power generation systems and the increasing dispersion of solar panels, a single solar charge controller has gradually been unable to meet the needs of the entire solar power generation system, and multiple solar charge controllers are required to work in parallel.

[0003] In the prior art, the input ends of multiple solar charge controllers in the system are respectively connected to the corresponding solar panels, while the output ends are connected in parallel to the battery or the inverter.

[0004] Such a parallel setting will cause uneven charging current between each solar charge controller. Therefore, when multiple solar charge controllers work in parallel, how to avoid large charging current value differences between each solar charge controller has become an urgent problem to be solved. Summary of the invention

[0005] The present application provides a solar power generation system and a current sharing control method of a parallel solar controller thereof, which improves the speed and accuracy of current sharing.

[0006] According to a first aspect of the present application, a current sharing control method for parallel solar controllers is provided, wherein a solar power generation system comprises a plurality of solar panels and solar controllers corresponding to the solar panels one by one, wherein an input end of the solar controller is connected to the corresponding solar panel, and an output end of the solar controller is connected to an energy storage device; and communication connection is achieved between the solar controllers based on a serial communication protocol;

[0007] The current sharing control method of the parallel solar controller is applied to the solar controller; the current sharing control method of the parallel solar controller includes:

[0008] Obtaining state parameters and identity information of all the solar controllers in the solar power generation system, wherein the state parameters include target voltage, charging stage and charging current;

[0009] Based on the identity information, determining the control role of each of the solar controllers, wherein the control roles include a master controller and a slave controller;

[0010] In the case where the executing controller is the slave controller, following the target voltage and the charging stage on the master controller;

[0011] After that, the target voltage of the execution controller is adjusted in a cyclic step according to the charging current of all the solar controllers in the system.

[0012] Optionally, after determining the control role of each solar controller based on the identity information, the method further includes:

[0013] In the case where the execution controller is the main controller, the main controller is adjusted to a maximum power point tracking mode.

[0014] Optionally, the identity information includes an identity identification number;

[0015] The step of determining the control role of each solar controller based on the identity information includes:

[0016] Determine the solar controller with the smallest identification number as the main controller;

[0017] The solar controllers other than the master controller are all determined as slave controllers.

[0018] Optionally, following the target voltage and the charging stage on the main controller comprises:

[0019] adjusting the charging phase of the execution controller to be the same as the charging phase of the main controller;

[0020] and, adjusting the target voltage of the execution controller to be the same as the target voltage of the main controller.

[0021] Optionally, the stepping-by-step adjustment of the target voltage of the execution controller according to the state parameter of the execution controller and the average value of the charging current in the system includes:

[0022] Calculating the average value according to the charging currents of all the solar controllers in the solar power generation system;

[0023] In a case where the difference between the average value and the charging current of the execution controller is greater than a preset current difference, the target voltage of the execution controller is increased by a step value and the process returns to the step of calculating the average value.

[0024] Optionally, after calculating the average value according to the charging currents of all the solar controllers in the solar power generation system, the method further includes:

[0025] In the case where the difference between the average value and the charging current of the execution controller is less than or equal to the preset current difference, determining whether the target voltage and the charging current of the execution controller meet a target reduction condition, wherein the target reduction condition is that the charging current of the execution controller is greater than the average value and the target voltage of the execution controller is greater than the target voltage of the main controller;

[0026] When the target voltage and the charging current of the execution controller meet the target reduction condition, the target voltage of the execution controller is reduced by the step value and the average value is calculated.

[0027] When the target voltage and the charging current of the execution controller do not satisfy the target reduction condition, the process directly returns to the step of calculating the average value.

[0028] Optionally, the serial communication protocol includes a Modbus communication protocol or a CAN communication protocol.

[0029] Optionally, the step value is less than or equal to 0.1V.

[0030] According to a second aspect of the present application, a solar controller is provided, and the solar controller is used to execute any current sharing control method of parallel solar controllers described in the first aspect.

[0031] According to a third aspect of the present application, a solar power generation system is provided, comprising: a plurality of solar panels and the solar controllers described in the second aspect corresponding one to the solar panels; the input end of the solar controller is connected to the corresponding solar panel, and the output end of the solar controller is connected to an energy storage device; and the solar controllers are connected to each other based on a serial communication protocol.

[0032] The solar power generation system and the current sharing control method of the parallel solar controller provided by the embodiment of the present invention obtain the state parameters and identity information of all solar controllers in the solar power generation system during the current sharing process, wherein the state parameters include the target voltage, the charging stage and the charging current. Based on the identity information, the control role of each solar controller is determined, wherein the control role includes the master controller and the slave controller. In the case where the execution controller is a slave controller, the target voltage and the charging stage on the master controller are followed. After following, the target voltage of the execution controller is adjusted cyclically and stepwise according to the charging current of all solar controllers in the system, thereby realizing the current sharing control of each solar controller in parallel in the solar power generation system. On the one hand, the method uses a serial communication protocol to communicate and connect each solar controller, thereby improving the sharing speed of the state parameters. On the other hand, the current is shared by stepping through the target voltage, thereby greatly improving the accuracy of the current sharing.

[0033] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the present application or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 A schematic diagram of the composition of a solar power generation system provided by an embodiment of the present invention;

[0036] Figure 2 A schematic flow chart of a current sharing control method for a parallel solar controller provided in an embodiment of the present invention;

[0037] Figure 3 A schematic flow chart of a current sharing control method for a parallel solar controller provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0039] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in this application should be understood by people with ordinary skills in the field to which this application belongs. The words "first", "second" and similar words used in this application do not indicate any order, quantity or importance, but are only used to distinguish different components. "Including" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0040] As mentioned in the background technology, in the prior art, the input ends of multiple solar charging controllers in the system are respectively connected to their corresponding solar panels, while the output ends are connected in parallel to batteries or inverters. Such a parallel setting will cause the problem of uneven charging current between the solar charging controllers. The inventors have found that the main reasons for this problem are: on the one hand, each controller in the system will have sampling and calibration deviations, and it is impossible for all controllers to enter the floating charging stage from the boost stage at the same time. On the other hand, if multiple controllers perform MPPT point tracking control at the same time, the charging current of the controller will vary greatly, greatly increasing the difficulty of achieving current balancing.

[0041] In order to solve the above problems, the present invention proposes a current sharing control method for parallel solar controllers, which is applied to the solar controller in the solar power generation system. For the convenience of understanding, before introducing the current sharing control method for parallel solar controllers proposed by the present invention, the solar controller to which it is applied and the solar power generation system in which it is located are first introduced. Figure 1 A schematic diagram of a solar power generation system according to an embodiment of the present invention is shown in FIG. Figure 1The solar power generation system 100 includes a plurality of solar panels 101 and solar controllers 102 corresponding to the solar panels 101. For example, the number of solar panels 101 and solar controllers 102 in a solar power generation system 100 can be 16. The solar controller 102 refers to a solar charging control device arranged between the power output end of the corresponding solar panel and the input end of the energy storage device, and is used to control the real-time working state of the corresponding solar panel 101. For example, the solar controller 102 can be an MPPT (Maximum Power Point Tracking) solar controller. The input end of the solar controller 102 is connected to the corresponding solar panel 101, and the output end of the solar controller 102 is connected to the energy storage device 103. The communication connection between the solar controllers 102 in the solar power generation system 100 is realized based on the serial communication protocol, so that information transmission can be realized between the solar controllers 102 in the system.

[0042] Figure 2 A flow chart of a current sharing control method for a parallel solar controller provided by an embodiment of the present invention, combined with Figure 1 and Figure 2 , a current sharing control method for parallel solar controllers, comprising:

[0043] S201, obtaining status parameters and identity information of all solar controllers in the solar power generation system.

[0044] Specifically, the status parameters may include target voltage, charging stage, charging voltage, charging current and temperature. Identity information refers to an identifier that can distinguish the identity of the solar controller. The identity information may include an identity number that corresponds to the solar controller one by one. The identity number of each solar controller in the solar power generation system is unique. During the operation of the solar power generation system, each solar controller actively reports its own status parameters and identity information through a serial communication protocol. The frequency of information reporting may be once every preset time interval. At the same time, each solar controller also monitors the data sent by other solar controllers on the communication line to obtain the status parameters and identity information of other solar controllers.

[0045] S202: Determine the control role of each solar controller based on the identity information.

[0046] Specifically, the control role refers to the functional role of each solar controller in the current sharing control method. The control roles include the master controller and the slave controller. The master controller plays a leading role and provides the target voltage and charging stage benchmark for other slave controllers. The slave controller performs subsequent current sharing adjustments based on this benchmark. Exemplarily, the solar controller with the identity number of the preset number is determined as the only master controller, and the other solar controllers in the solar power generation system are determined as slave controllers, which can ensure the consistency and predictability of the status of all solar controllers in the solar power generation system.

[0047] S203: When the execution controller is the main controller, adjust the main controller to a maximum power point tracking mode.

[0048] Specifically, the execution controller refers to the solar controller that executes the method, that is, the execution subject of the method. The execution controller is the main controller, that is, the control role of the solar controller that currently executes the method is the main controller of the solar power generation system. The maximum power point tracking mode is also called the MPPT mode. The main controller in the maximum power point tracking mode can adjust the output power of its corresponding solar panel according to different external environmental characteristics such as ambient temperature and light intensity, so that the solar panel always outputs the maximum power it can currently reach, wherein the method for adjusting the output power can include rotating the setting direction and angle of each power generation unit on the solar panel. It should be particularly noted that this step can be selected, replaced or deleted according to actual needs, and no restrictions are made here.

[0049] S204: When the executing controller is a slave controller, follow the target voltage and charging stage on the master controller.

[0050] Specifically, the execution controller is a slave controller, that is, the control role of the solar controller currently executing the present method is a slave controller, which is one of the multiple slave controllers of the solar power generation system. Following the target voltage and charging stage on the master controller means that the target voltage of the execution controller actively follows the target voltage of the master controller, and the charging stage of the execution controller also actively follows the charging stage of the master controller. Exemplarily, the target voltage of the execution controller can be set to be equal to the target voltage of the master controller or positively correlated with the target voltage of the master controller. The charging stage of the execution controller can be set to be the same as the charging stage of the master controller.

[0051] S205, after following, according to the charging current of all solar controllers in the solar power generation system, the target voltage of the execution controller is adjusted in a cyclic step.

[0052] Specifically, the cyclic step adjustment is an operation step obtained by cyclically combining the judgment of the necessity of adjustment and the step adjustment, wherein each adjustment amount of the step adjustment is a preset step value, and illustratively, the preset step value can be less than or equal to 0.1V. After following the target voltage and charging stage of the main controller, the execution controller further determines whether the charging current of the execution controller meets the current sharing requirement condition according to the charging current of all solar controllers in the solar power generation system, and then, when the execution controller meets the current sharing requirement, the target voltage of the execution controller is step-adjusted until the execution controller does not meet the current sharing requirement, wherein the current sharing requirement condition refers to the condition used to determine whether the current state of the solar controller needs to be adjusted for the current average of each controller in the system. If the charging current of the execution controller meets the current sharing requirement condition, it means that the execution controller needs to make further adjustments, and if the charging current of the execution controller does not meet the current sharing requirement condition, it means that the execution controller does not need to make further adjustments. Exemplarily, the current sharing requirement condition may include that the absolute value of the difference between the charging current and the average charging current of each solar controller in the system needs to be less than a preset value.

[0053] When the charging current of the execution controller meets the current sharing requirement, the target voltage of the execution controller can be further adjusted in steps. The corresponding step adjustment means that if the charging current of the execution controller is lower than the average level in the system, the target voltage of the execution controller will be increased accordingly, and if the charging current of the execution controller is higher than the average level in the system, the target voltage of the execution controller will be lowered accordingly.

[0054] The current sharing control method of parallel solar controllers in this embodiment obtains the state parameters and identity information of all solar controllers in the solar power generation system, wherein the state parameters include the target voltage, charging stage and charging current. Based on the identity information, the control role of each solar controller is determined, wherein the control roles include the master controller and the slave controller. In the case where the execution controller is a slave controller, the target voltage and charging stage on the master controller are followed. After following, the target voltage of the execution controller is cyclically stepped according to the charging current of all solar controllers in the system, thereby realizing the current sharing control of each solar controller in parallel in the solar power generation system. On the one hand, this method utilizes a serial communication protocol to communicate and connect each solar controller, facilitating the sharing of state parameters, and on the other hand, the current is shared by stepping through the target voltage adjustment, which greatly improves the accuracy of current sharing.

[0055] Figure 3 A flow chart of a current sharing control method for a parallel solar controller provided in an embodiment of the present invention is provided. Based on the above embodiment, Figure 1 and Figure 3The current sharing control method of the parallel solar controller may also include:

[0056] S301, obtaining status parameters and identity information of all solar controllers in the solar power generation system.

[0057] Specifically, the state parameters may include a target voltage, a charging stage, a charging voltage, a charging current, and a temperature. The identity information may include an identity identification number (also referred to as an ID number) that corresponds one-to-one to the solar controller. During the operation of the solar power generation system, each solar controller actively reports its own state parameters and identity information through a serial communication protocol. The frequency of the parameter report may be reported once every preset time interval. For example, the preset interval may be 1 second. The serial communication protocol may include a Modbus communication protocol or a CAN communication protocol. At the same time, each solar controller also monitors the data sent by other solar controllers on the communication line to realize online statistics of the online number, state parameters, and identity information of other solar controllers.

[0058] S302: Determine the solar controller with the smallest identification number as the main controller.

[0059] Specifically, the solar controller with the smallest identification number among all online solar controllers is determined as the main controller. The main controller plays a leading role in the solar power generation system and provides the target voltage and charging stage benchmark for other slave controllers in the system. Selecting the solar controller with the smallest identification number as the main controller can ensure the consistency and predictability of the overall adjustment of the system. Online means that the communication is online. The solar controller in the online state has information exchange with other solar controllers. After being determined as the main controller, the solar controller can add an identity to the information it sends.

[0060] S303, all solar controllers other than the master controller are determined as slave controllers.

[0061] Specifically, among all online solar controllers, all other solar controllers except the master controller are determined as slave controllers. The slave controller can make subsequent current sharing adjustments based on the target voltage provided by the master controller and the benchmark of the charging stage. It should be noted here that the execution order of step S302 and step S303 is not distinguished. The flowchart only takes S302 first and S303 later as an example. In practice, S303 can also be first and S302 later, or S302 and S303 can be executed in parallel.

[0062] S304: When the execution controller is the main controller, adjust the main controller to a maximum power point tracking mode.

[0063] Specifically, the execution controller refers to the solar controller that executes the method, that is, the execution subject of the method. The execution controller is the main controller, that is, the control role of the solar controller that currently executes the method is the main controller of the solar power generation system. The maximum power point tracking mode is also called the MPPT mode. The main controller in the maximum power point tracking mode can adjust the output power of its corresponding solar panel according to different external environmental characteristics such as ambient temperature and light intensity, so that the solar panel always outputs the maximum power it can currently reach, wherein the method for adjusting the output power can include rotating the setting direction and angle of each power generation unit on the solar panel. It should be particularly noted that this step can be selected, replaced or deleted according to actual needs, and no restrictions are made here.

[0064] S305, adjusting the charging phase of the execution controller to be the same as the charging phase of the main controller.

[0065] Specifically, the solar controller will switch its charging stage according to the state of itself, the solar panel and / or the corresponding battery during operation. Exemplarily, the charging stage of the solar controller may include a constant current charging stage (also called a high current charging stage), a constant voltage charging stage and a floating charging stage. One of the operations of following the target voltage and charging stage on the master controller is to adjust the charging stage of the execution controller to be the same as the charging stage of the master controller when the execution controller is a slave controller.

[0066] S306, adjusting the target voltage of the execution controller to be the same as the target voltage of the main controller.

[0067] Specifically, another operation of following the target voltage and charging stage on the master controller is, when the execution controller is a slave controller, adjusting the target voltage of the execution controller to be equal to the target voltage of the master controller. It should be particularly noted here that the execution order of step S305 and step S306 is not distinguished, and the flowchart only takes S305 first and S306 later as an example. In practice, S306 can also be first and S305 later, or S305 and S306 can be executed in parallel.

[0068] S307, calculating an average value according to the charging currents of all solar controllers in the solar power generation system.

[0069] Specifically, the execution controller adds the local charging current and the collected charging current of other solar controllers in the solar power generation system to obtain the total charging current provided by the solar power generation system for the energy storage device. The total charging current is then divided by the number of solar controllers that can be online in the system to determine the average charging current of each solar controller in the solar power generation system.

[0070] S308: When the difference between the average value and the charging current of the execution controller is greater than the preset current difference, the target voltage of the execution controller is increased by the step value and the process returns to the step of calculating the average value.

[0071] Specifically, the execution controller whose control role is a slave controller also calculates the difference between the average value and the charging current of the execution controller, and then determines whether the difference is greater than the preset current difference, wherein the preset current difference is the preset upper limit threshold of the difference, and its value can be determined according to experiments. For example, the preset current difference can be set to 1A. If the difference between the average value and the charging current of the execution controller is greater than the preset current difference, it indicates that the charging current of the execution controller is significantly different from the average level of the charging current of the system, which may increase the risk of damage to the solar power generation system. In this case, the execution controller whose control role is a slave controller can increase its own target voltage by the step value, thereby realizing the autonomous improvement of the charging current of the execution controller, wherein the step value can be greater than 0 and less than or equal to 0.1V. By gradually adjusting the target voltage in small steps, it is possible to avoid causing excessive impact on the system and achieve smooth current sharing. It should be particularly noted here that the step of returning to calculate the average value refers to returning to step S307 and recalculating the average value based on the latest acquired state parameters of all solar controllers.

[0072] S309: When the difference between the average value and the charging current of the execution controller is less than or equal to the preset current difference, determine whether the target voltage and charging current of the execution controller meet the target reduction condition.

[0073] Specifically, if the difference between the average value and the charging current of the execution controller is less than or equal to the preset current difference, it may indicate that the charging current of the execution controller has met the current sharing requirement, that is, the charging current of the execution controller is not much different from the average value of the system charging current; it may also indicate that the difference between the average value and the charging current of the execution controller is a negative value, that is, the charging current of the execution controller is greater than the average value. In the case where the charging current of the execution controller is greater than the average value, it is necessary to further determine whether the charging current of the execution controller meets the target reduction condition, where the target reduction condition is that the charging current of the execution controller is greater than the average value and the target voltage of the execution controller is greater than the target voltage of the main controller.

[0074] S310: When the target voltage and charging current of the execution controller both meet the target reduction condition, the target voltage of the execution controller is reduced by a step value and the process returns to the step of calculating the average value.

[0075] Specifically, the target voltage of the execution controller meets the target reduction condition, which means that the target voltage of the execution controller is greater than the target voltage of the main controller, which indicates that the step adjustment in the previous cycle caused the target voltage of the execution controller to exceed the target voltage of the main controller. The charging current meets the target reduction condition, which means that the charging current of the execution controller is greater than the average charging current in the system. When the target voltage and charging current of the execution controller both meet the target reduction condition, the target voltage of the execution controller can be reduced by the step value, and illustratively, the step value can be equal to 0.1V.

[0076] S311. When the target voltage and charging current of the execution controller do not meet the target reduction condition, directly return to the step of calculating the average value.

[0077] In the cyclic step adjustment step of the current sharing control method of the parallel solar controller provided in this embodiment, the average value is calculated according to the charging current of all solar controllers in the solar power generation system. When the difference between the average value and the charging current of the execution controller is greater than the preset current difference, the target voltage of the execution controller is increased by the step value and the step of calculating the average value is returned. When the difference between the average value and the charging current of the execution controller is less than or equal to the preset current difference, it is determined whether the target voltage and charging current of the execution controller meet the target reduction condition. When the target voltage and charging current of the execution controller meet the target reduction condition, the target voltage of the execution controller is reduced by the step value and the step of calculating the average value is returned. When the target voltage and charging current of the execution controller do not meet the target reduction condition, the step of calculating the average value is directly returned, so as to realize the cyclic step adjustment of the charging current, and the execution controller monitors its own charging current in real time, and compares and adjusts it with the latest acquired state parameters of other controllers, thereby improving the current sharing efficiency.

[0078] Optionally, based on the above-mentioned embodiment, the current sharing control method of the parallel solar controller can also add a step of judging whether the difference between the target voltage value of the execution controller and the target voltage value of the main controller is greater than or equal to three times the step value after each increase in the step value. For example, when the step value is equal to 0.1V, the three times step value is equal to 0.3V. If the difference between the target voltage value of the execution controller and the target voltage value of the main controller is greater than or equal to three times the step value, the cycle and the increase of the step value will no longer continue, and a reminder message will be generated and sent to the monitoring device to remind the on-duty personnel to conduct inspections and maintenance to prevent further damage to the equipment caused by current imbalance. If the difference between the target voltage value of the execution controller and the target voltage value of the main controller is less than three times the step value, the original process will continue to be implemented.

[0079] In the current sharing control method of the parallel solar controller provided in this embodiment, the executive controller can dynamically adjust its own target voltage according to the state parameters obtained in real time to respond to the current sharing requirements of the system. By gradually adjusting the target voltage in small steps, it is possible to avoid excessive impact on the system by directly adjusting the charging current, while achieving smooth current sharing. The maximum voltage adjustment limit is set to prevent damage to the battery or controller caused by excessive voltage. The executive controller also monitors its own charging current in real time and compares it with the state parameters of other controllers in the system to quickly respond to the requirements of current sharing control. In this method, multiple solar controllers can work together to ensure that the charging current is evenly distributed among the controllers, thereby improving the charging efficiency and stability of the entire system.

[0080] The embodiment of the present invention also provides a solar controller. Figure 1 The solar controller 102 is used to execute the current sharing control method of the parallel solar controllers of any of the previous embodiments.

[0081] The embodiment of the present invention also provides a solar power generation system. Figure 1 The solar power generation system 100 includes a plurality of solar panels 101 and solar controllers 102 corresponding to the solar panels 101. The input end of the solar controller 102 is connected to the corresponding solar panel 101, and the output end of the solar controller 102 is connected to the energy storage device 103; the solar controllers 102 are connected to each other based on a serial communication protocol.

[0082] Some embodiments of the present application are described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0083] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present application (including the claims) is limited to these examples. In line with the concept of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present application as above, which are not provided in detail for the sake of simplicity.

[0084] Although the present application has been described in conjunction with specific embodiments thereof, many alternatives, modifications and variations of these embodiments will be apparent to those skilled in the art in light of the foregoing description.

Claims

1. A current sharing control method for parallel solar controllers. It is characterized in that The solar power generation system includes a plurality of solar panels and solar controllers corresponding to the solar panels one by one, wherein the input end of the solar controller is connected to the corresponding solar panel, and the output end of the solar controller is connected to the energy storage device; the solar controllers are connected to each other based on a serial communication protocol; The current sharing control method of the parallel solar controller is applied to the solar controller; The current sharing control method of the parallel solar controller includes: Obtaining state parameters and identity information of all the solar controllers in the solar power generation system, wherein the state parameters include target voltage, charging stage and charging current; Based on the identity information, determining the control role of each of the solar controllers, wherein the control roles include a master controller and a slave controller; In the case where the executing controller is the slave controller, following the target voltage and the charging stage on the master controller; After that, the target voltage of the execution controller is adjusted in a cyclic step according to the charging current of all the solar controllers in the system.

2. The current sharing control method of the parallel solar controller according to claim 1, It is characterized in that After determining the control role of each solar controller based on the identity information, the method further includes: In the case where the execution controller is the main controller, the main controller is adjusted to a maximum power point tracking mode.

3. The current sharing control method of the parallel solar controller according to claim 1, It is characterized in that The identity information includes an identity identification number; The step of determining the control role of each solar controller based on the identity information includes: Determine the solar controller with the smallest identification number as the main controller; The solar controllers other than the master controller are all determined as slave controllers.

4. The current sharing control method of the parallel solar controller according to claim 1, It is characterized in that The following the target voltage and the charging stage on the main controller includes: adjusting the charging phase of the execution controller to be the same as the charging phase of the main controller; and, adjusting the target voltage of the execution controller to be the same as the target voltage of the main controller.

5. The current sharing control method of the parallel solar controller according to claim 1, It is characterized in that The step of adjusting the target voltage of the execution controller in a cyclic step according to the state parameter of the execution controller and the average value of the charging current in the system includes: Calculating the average value according to the charging currents of all the solar controllers in the solar power generation system; In a case where the difference between the average value and the charging current of the execution controller is greater than a preset current difference, the target voltage of the execution controller is increased by a step value and the process returns to the step of calculating the average value.

6. The current sharing control method of the parallel solar controller according to claim 5, It is characterized in that After calculating the average value according to the charging current of all the solar controllers in the solar power generation system, the method further includes: In the case where the difference between the average value and the charging current of the execution controller is less than or equal to the preset current difference, determining whether the target voltage and the charging current of the execution controller meet a target reduction condition, wherein the target reduction condition is that the charging current of the execution controller is greater than the average value and the target voltage of the execution controller is greater than the target voltage of the main controller; When the target voltage and the charging current of the execution controller meet the target reduction condition, the target voltage of the execution controller is reduced by the step value and the average value is calculated again; When the target voltage and the charging current of the execution controller do not satisfy the target reduction condition, the process directly returns to the step of calculating the average value.

7. The current sharing control method of the parallel solar controller according to any one of claims 1 to 6, It is characterized in that The serial communication protocol includes Modbus communication protocol or CAN communication protocol.

8. The current sharing control method of the parallel solar controller according to any one of claims 5 or 6, It is characterized in that The step value is less than or equal to 0.1V.

9. A solar controller, It is characterized in that Used to implement the current sharing control method of the parallel solar controllers described in any one of claims 1-8.

10. A solar power generation system, It is characterized in that include: A plurality of solar panels and a solar controller as described in claim 9 corresponding to the solar panels one by one; the input end of the solar controller is connected to the corresponding solar panel, and the output end of the solar controller is connected to an energy storage device; and the communication connection between each of the solar controllers is achieved based on a serial communication protocol.

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