Collected leakage current minimization control method suitable for switching working conditions of photovoltaic direct-current converter

Abstract

The invention discloses a collection leakage current minimization control method suitable for the switching working condition of a photovoltaic direct current converter, and belongs to the technical field of power grid control. The method comprises the following steps: for a direct-current power supply system formed by collecting a plurality of photovoltaic direct-current converters, respectively calculating a phase shift angle of each photovoltaic direct-current converter so as to minimize the collected leakage current of the direct-current power supply system; monitoring the quit or newly-added access condition of the photovoltaic DC converter in the DC power supply system in real time; updating the number of the photovoltaic direct-current converters in the direct-current power supply system according to the condition that the photovoltaic direct-current converters exit or are newly added and connected; recalculating the optimal phase shift angle of each photovoltaic direct-current converter according to the number of the updated photovoltaic direct-current converters; and controlling each photovoltaic direct-current converter to perform uniform phase shift according to the optimal phase shift angle. According to the method, after the convergence leakage current balance is damaged, new balance can be rapidly returned by taking the minimum convergence leakage current as a target.

Description

Technical Field

[0001] This invention belongs to the technical field of power electronics and power network control, and mainly relates to a method for minimizing the pooled leakage current under the operation conditions of photovoltaic DC converters. Background Technology

[0002] In photovoltaic-integrated low-voltage direct current (PV-LVDC) systems, photovoltaic panel arrays are generally connected using non-isolated DC-DC converters, which offer advantages such as high efficiency and low cost. However, non-isolated DC-DC converters eliminate the need for transformers, resulting in a lack of electrical isolation between the photovoltaic panels and the DC bus. Furthermore, the large area of ​​photovoltaic panels leads to significant parasitic capacitance to ground. The high-frequency switching of power devices in the non-isolated DC-DC converter can generate high-frequency time-varying voltages acting on these parasitic capacitances, thus inducing leakage current (also known as common-mode current or ground current) in the common-mode loop composed of the panel parasitic capacitance, the non-isolated DC-DC converter, the DC grid, and the ground. As photovoltaic capacity increases, the leakage current generated by each individual non-isolated DC-DC converter in the PV-LVDC system will also converge at the DC bus, forming a system-level pooled leakage current. The presence of this pooled leakage current can cause DC bus current distortion, affecting power quality and potentially endangering personnel and equipment safety, thus impacting the safe and stable operation of the PV-LVDC system.

[0003] Furthermore, in actual PV-LVDC systems, there are frequent situations where photovoltaic DC converters fail and shut down or new DC converters are added. In a parallel system of multiple DC converters that have been operating stably and have achieved minimum pooled leakage current, the sudden shutdown or addition of a converter will disrupt the stable state of the minimum pooled leakage current of the PV-LVDC system, making it impossible to continue to achieve minimum pooled leakage current tracking control of the parallel system. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method for minimizing the pooled leakage current under the conditions of photovoltaic DC converter commissioning and decommissioning. This method can quickly restore the pooled leakage current balance after it has been disrupted and increased, thereby minimizing the pooled leakage current as much as possible.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, the present invention provides a method for minimizing pooled leakage current under photovoltaic DC converter commissioning and shutdown conditions, comprising:

[0007] For a DC power supply system composed of multiple photovoltaic DC converters, calculate the optimal phase shift angle for each photovoltaic DC converter to minimize the combined leakage current of the DC power supply system.

[0008] Monitor the connection status of photovoltaic DC converters in the DC power supply system, and in response to the situation where photovoltaic DC converters are removed or added to the DC power supply system, obtain the number of photovoltaic DC converters after removal or addition.

[0009] Based on the number of photovoltaic DC converters that are disconnected or added to the grid

[0010] Recalculate the optimal phase shift angle for each photovoltaic DC converter;

[0011] Based on the optimal phase shift angle, each photovoltaic DC converter is controlled to perform uniform phase shift, thereby minimizing the leakage current collected in the DC power supply system.

[0012] Optionally, the present invention monitors the access status of the photovoltaic DC converter in the DC power supply system to obtain the commissioning and decommissioning status of the photovoltaic DC converter, specifically including: polling the heartbeat frames of each photovoltaic DC converter through the communication bus;

[0013] In response to the detection of a heartbeat frame for a newly added photovoltaic DC-DC converter device ID, the new access event is confirmed to be valid, and the newly added photovoltaic DC-DC converter device ID is updated to the preset photovoltaic DC-DC converter device list; in response to the loss of a heartbeat frame for an existing photovoltaic DC-DC converter device ID, the corresponding photovoltaic DC-DC converter device is considered to have exited, and the corresponding photovoltaic DC-DC converter device information is deleted from the photovoltaic DC-DC converter device list.

[0014] Based on the updated list of photovoltaic DC-DC converter devices, determine the number of photovoltaic DC-DC converters that will be connected to the DC power supply system in real time.

[0015] Optionally, to further avoid misjudgments of commissioning / decommissioning situations, such as misjudgments of converter decommissioning due to communication anomalies, in some possible embodiments, monitoring the access status of the photovoltaic DC converter in the DC power supply system further includes:

[0016] Obtain the input voltage, input current, output voltage, and output current of the DC branch corresponding to each photovoltaic DC converter, and calculate the input power and output power.

[0017] When polling the heartbeat frames of each photovoltaic DC converter via the communication bus, if the heartbeat frame of the original photovoltaic DC converter device ID is lost, it is determined whether the electrical quantity criteria are met: whether the input current and output current are both lower than 10% of the corresponding rated current and maintained for more than the set time, and whether the input voltage is maintained above 90% of the port open circuit voltage and maintained for more than the set time.

[0018] If both the heartbeat frame loss and the electrical quantity criterion are met simultaneously, the corresponding photovoltaic DC converter exit event is deemed valid.

[0019] In addition, other electrical quantities and switching quantities, such as the status of the relay auxiliary contacts connected to the photovoltaic DC converter, can be used to further ensure the confirmation of the DC converter's on / off status and reduce system instability caused by the subsequent adjustment of the phase angle after misjudgment of on / off status.

[0020] Optionally, each photovoltaic DC converter in the DC power supply system is connected in parallel.

[0021] Optionally, the optimal phase angle of the DC power supply system is ,in This indicates the number of photovoltaic DC converters with the same switching frequency connected in parallel in the DC power supply system;

[0022] For all photovoltaic-DC converters connected in parallel with the same switching frequency, the optimal phase shift angle for each photovoltaic-DC converter is calculated using the following formula:

[0023] ,

[0024] in, Indicates the first The optimal phase shift angle for a photovoltaic DC-DC converter This indicates the number of photovoltaic DC converters with the same switching frequency that are connected in parallel in the DC power supply system.

[0025] Optionally, if all photovoltaic-DC converters connected in parallel in the DC power supply system have multiple switching frequencies, then the photovoltaic-DC converters with the same switching frequency are grouped together. For each photovoltaic-DC converter in each group, the optimal phase shift angle is calculated according to the following formula:

[0026]

[0027] In the formula, Indicates the first The number of photovoltaic DC converters connected in parallel in a DC power supply system at various switching frequencies. For the first The optimal phase shift angle for a photovoltaic DC-DC converter.

[0028] Optionally, the method of the present invention further includes: sorting the photovoltaic DC converters at each switching frequency according to the order in which they are connected to the DC power supply system;

[0029] After calculating the optimal phase shift angle for each photovoltaic DC converter, the optimal phase shift angles are sequentially sent to the control loop of each photovoltaic DC converter according to the aforementioned order.

[0030] Based on the above sorting, when a new photovoltaic DC converter is added to the network, the newly added photovoltaic DC converter is updated to the end of the original sorting; when a photovoltaic DC converter is removed from the network, the photovoltaic DC converters in the current access status are re-sorted according to their access time.

[0031] After each calculation of the optimal phase shift angle, the phase shift angles are distributed sequentially according to the latest sorting.

[0032] Optionally, when the photovoltaic DC converter shifts phase uniformly according to the phase shift angle, the vector sum of the leakage currents of all photovoltaic DC converters is zero, and the combined leakage currents of each photovoltaic DC converter cancel each other out.

[0033] In a second aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the pooled leakage current minimization control method described in the first aspect.

[0034] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0035] In a DC power supply system that has achieved minimum control of pooled leakage current and is operating stably, this invention can quickly restore a new balance after the pooled leakage current balance of the DC power supply system is disrupted, and ensure that the pooled leakage current is minimized, by calculating the phase shift angle of each photovoltaic DC converter based on the number of DC converters connected to the DC power supply system and the switching frequency in real time, and performing uniform phase shift. Attached Figure Description

[0036] Figure 1 The diagram shown is a schematic diagram of a method for minimizing pooled leakage current provided by the present invention;

[0037] Figure 2 The diagram shows a DC power supply system of the present invention, which consists of multiple photovoltaic DC converters connected in parallel.

[0038] Figure 3 The figure shows the change in the collected leakage current when the fourth photovoltaic DC converter is deactivated at 10.01s in an embodiment of the present invention.

[0039] Figure 4 The diagram shows the phase shift angle configuration before and after the fourth photovoltaic DC converter is deactivated in an embodiment of the present invention, and the system leakage current vector diagram when the system reaches the minimum pooled leakage current stable state again.

[0040] Figure 5 The figure shows the change in the optimal phase shift angle of the minimum collected leakage current tracking control system before and after the fourth photovoltaic DC converter is deactivated in an embodiment of the present invention.

[0041] Figure 6 The figure shows the phase shift of the DC converter in the system before and after the fourth photovoltaic DC converter is deactivated in an embodiment of the present invention.

[0042] Figure 7 The figure shows the changes in the collected leakage current and the changes in the amplitude of the collected leakage current at the switching frequency when the fourth photovoltaic DC converter is deactivated in an embodiment of the present invention.

[0043] Figure 8 The figure shows the change in the collected leakage current when the eighth photovoltaic DC converter is added in 0.01s in an embodiment of the present invention.

[0044] Figure 9 The diagram shows the phase shift angle configuration before and after adding the eighth photovoltaic DC converter in this embodiment of the invention, and the system leakage current vector diagram when the system reaches the minimum pooling leakage current stable state again.

[0045] Figure 10 The figure shows the change in the optimal phase shift angle of the minimum pooling leakage current tracking control system before and after adding the eighth photovoltaic DC converter in this embodiment of the invention.

[0046] Figure 11 The figure shows the phase shift of the DC converter in the system before and after adding the eighth photovoltaic DC converter in an embodiment of the present invention;

[0047] Figure 12 The figure shows the changes in the collected leakage current and the changes in the amplitude of the collected leakage current at the switching frequency when an eighth photovoltaic DC converter is added in an embodiment of the present invention. Detailed Implementation

[0048] The following description, in conjunction with the accompanying drawings and specific embodiments, provides further details.

[0049] Example 1

[0050] refer to Figure 1 This embodiment introduces a method for minimizing the pooled leakage current to adapt to the commissioning and shutdown conditions of photovoltaic DC converters, including:

[0051] For a DC power supply system composed of multiple photovoltaic DC converters, calculate the optimal phase shift angle for each photovoltaic DC converter to minimize the combined leakage current of the DC power supply system.

[0052] Monitor the connection status of photovoltaic DC converters in the DC power supply system, and in response to the situation where photovoltaic DC converters are removed or added to the DC power supply system, obtain the number of photovoltaic DC converters after removal or addition.

[0053] Based on the number of photovoltaic DC converters that are disconnected or added to the grid

[0054] Recalculate the optimal phase shift angle for each photovoltaic DC converter;

[0055] Based on the optimal phase shift angle, each photovoltaic DC converter is controlled to perform uniform phase shift, thereby minimizing the leakage current collected in the DC power supply system.

[0056] By monitoring the withdrawal or addition of DC converters in the DC power supply system in real time, and updating the optimal phase shift angle of the system and the phase shift angle of each DC converter accordingly, the system can control the uniform phase shift angle of all photovoltaic DC converters. This allows the system to quickly return to a new balance after the system's pooled leakage current balance is disrupted, minimizing the pooled leakage current as much as possible.

[0057] Example 2

[0058] Based on the method of Embodiment 1, in this embodiment, each photovoltaic DC converter in the DC power supply system is connected in parallel. All photovoltaic DC converters may have the same switching frequency or have multiple different switching frequencies.

[0059] When the number of photovoltaic DC converters of the same frequency connected in parallel in a DC power supply system is fixed, the optimal phase angle of the DC power supply system is: ,in This indicates the number of photovoltaic DC converters with the same switching frequency that are connected in parallel in the DC power supply system.

[0060] For all photovoltaic-DC converters connected in parallel with the same switching frequency, the optimal phase shift angle for each photovoltaic-DC converter is calculated using the following formula:

[0061] ,

[0062] in, Indicates the first The optimal phase shift angle for a photovoltaic DC-DC converter This indicates the number of photovoltaic DC converters with the same switching frequency that are connected in parallel in the DC power supply system.

[0063] If all photovoltaic DC converters connected in parallel in a DC power supply system have multiple switching frequencies, then photovoltaic DC converters with the same switching frequency are grouped together. For each photovoltaic DC converter in each group, the optimal phase shift angle is calculated according to the following formula:

[0064]

[0065] In the formula, Indicates the first The number of photovoltaic DC converters connected in parallel in a DC power supply system at various switching frequencies. For the first The optimal phase shift angle for a photovoltaic DC-DC converter.

[0066] When the photovoltaic DC converter shifts phase uniformly according to the phase shift angle, the vector sum of the leakage currents of all photovoltaic DC converters is zero, and the combined leakage currents of each photovoltaic DC converter cancel each other out.

[0067] In some possible implementations, the method for minimizing the pooled leakage current to adapt to the commissioning and decommissioning conditions of photovoltaic DC converters also includes sorting the photovoltaic DC converters at each switching frequency according to the order of their connection to the DC power supply system, such as by sorting the devices in the device ID list.

[0068] After calculating the optimal phase shift angle for each photovoltaic DC converter, the optimal phase shift angles are sequentially sent to the control loop of each photovoltaic DC converter according to the aforementioned order.

[0069] Based on the above sorting, when a new photovoltaic DC converter is added to the network, the newly added photovoltaic DC converter will be updated to the end of the original sorting; when a photovoltaic DC converter exits the network, the sorting will be re-ordered according to the access time of the photovoltaic DC converters in the current access status, or the corresponding exited device will be deleted from the device ID list and the sorting will be automatically updated.

[0070] After each calculation to obtain the optimal phase shift angle, the phase shift angle is sequentially sent to the control loop of each DC converter according to the latest sorting to achieve uniform phase shift.

[0071] When the photovoltaic DC converter shifts the phase uniformly according to the phase shift angle, the vector sum of the leakage currents of all photovoltaic DC converters is zero, and the collected leakage currents of each photovoltaic DC converter cancel each other out, thus minimizing the area of ​​collected leakage current.

[0072] Example 3

[0073] Based on the same inventive concept as Embodiment 1, this embodiment specifically introduces the practical application of a method for minimizing pooled leakage current control.

[0074] Taking a DC power supply system consisting of seven photovoltaic DC converters connected in parallel at the same frequency as an example, the phase shift angle of each photovoltaic DC converter is first calculated using the following formula:

[0075] ,

[0076] The phase shift angles of the seven photovoltaic DC converters are 0°, 51.43°, 102.86°, 154.29°, 205.71°, 257.14°, and 308.57°, respectively. Each photovoltaic DC converter is uniformly phase-shifted according to its corresponding phase shift angle. At this time, the vector sum of the leakage currents of the seven DC converters is zero, and the combined leakage current is minimized.

[0077] like Figure 3 As shown, the system has the minimum leakage current at this time, with a leakage current amplitude of only 0.022A at the switching frequency.

[0078] After the system stabilizes, the fourth photovoltaic DC converter is deactivated at 0.01 seconds, and the leakage current changes are recorded as follows: Figure 3 As shown, after the photovoltaic DC converter is deactivated, the system's pooled leakage current increases significantly, reaching 1.89A at the switching frequency.

[0079] like Figure 4 As shown in (a), in the DC power supply system, the phase shift angle of each converter after the fourth photovoltaic DC converter is automatically shifted forward, and the optimal phase shift angle required by the DC power supply system after the change in the number of photovoltaic DC converters is recalculated. The remaining photovoltaic DC converters are then uniformly phase-shifted according to the changed optimal phase shift angle. At this time, the leakage current vector diagram of each photovoltaic DC converter in the system is shown in Figure (a). Figure 4 As shown in (b).

[0080] After the fourth converter exits, the system's cumulative leakage current increases rapidly. The controller responds quickly, calculating the optimal phase shift angle required for each photovoltaic-DC converter at this point. The calculation process is as follows: Figure 5 As shown, the optimal phase shift angle of the system before the converter exits is... After the converter exits, the optimal phase shift angle of the system is .

[0081] The phase shift angles of the remaining converters in the system are adjusted according to the optimal phase shift angle change. The remaining six converters are uniformly phase shifted by 0°, 60°, 120°, 180°, 240°, and 300° respectively. Figure 6 As shown.

[0082] like Figure 7 As shown, the pooled leakage current at the system switching frequency increases briefly after the converter is shut down, but decreases rapidly after the phase angle of the photovoltaic DC converter is adjusted. When the DC power supply system reaches a new stable state with minimum pooled leakage current, the amplitude of the pooled leakage current at the switching frequency is only 0.061A.

[0083] Example 4

[0084] Based on the same inventive concept as Embodiment 1, this embodiment specifically introduces a method for minimizing pooled leakage current control.

[0085] Taking a DC power supply system consisting of seven photovoltaic DC converters connected in parallel at the same frequency as an example, the phase shift angle of each photovoltaic DC converter is first calculated using the following formula:

[0086] ,

[0087] The phase shift angles of the seven photovoltaic DC converters are 0°, 51.43°, 102.86°, 154.29°, 205.71°, 257.14°, and 308.57°, respectively. Each photovoltaic DC converter is uniformly phase-shifted according to its corresponding phase shift angle. At this time, the vector sum of the leakage currents of the seven DC converters is zero, and the combined leakage current is minimized.

[0088] like Figure 8 As shown, the system has the minimum leakage current at this time, with a leakage current amplitude of only 0.022A at the switching frequency.

[0089] After the system stabilizes, a eighth photovoltaic DC converter is added at 0.01 seconds, and the leakage current changes are recorded as follows: Figure 8 As shown, after the addition of the photovoltaic DC converter, the system's pooled leakage current increased significantly, reaching 1.74A at the switching frequency.

[0090] like Figure 9 As shown in (a), when a new converter is added to the system, this converter is added to the end of the system, and its phase shift angle is set to... And recalculate the optimal phase shift angle required by the system after the change in the number of converters, and uniformly shift the existing converters in the system according to the changed optimal phase shift angle, such as... Figure 9 As shown in (a), the leakage current vector diagram of each DC converter in the system at this time is as follows: Figure 9 As shown in (b).

[0091] After the addition of the eighth converter, the system's pooled leakage current increased rapidly, and the controller responded quickly. The optimal phase shift angle required for each photovoltaic-DC converter at this point was calculated, as follows: Figure 10 As shown, the optimal phase shift angle of the system before the converter exits is... After adding the converter, the optimal phase shift angle of the system is .

[0092] The phase shift angles of the remaining converters in the system are adjusted according to the optimal phase shift angle change. The remaining six converters are uniformly phase shifted by 0°, 45°, 90°, 135°, 180°, 225°, 270°, and 315° respectively. Figure 11 As shown.

[0093] like Figure 12As shown, the pooled leakage current at the system switching frequency increases briefly after the addition of the converter, but decreases rapidly after the phase shift angle of the photovoltaic DC converter is adjusted. When the DC power supply system reaches a new stable state with minimum pooled leakage current, the amplitude of the pooled leakage current at the switching frequency is only 0.093A.

[0094] Example 5

[0095] Based on the method for minimizing pooled leakage current adapted to the commissioning and decommissioning conditions of photovoltaic DC converters described in Example 1, the present invention provides a control system for minimizing pooled leakage current, including: a controller and a DC power supply system composed of multiple photovoltaic DC converters.

[0096] The controller includes a monitoring module and a phase shift angle calculation module;

[0097] The monitoring module is used to monitor the status of photovoltaic DC converters being disconnected or newly connected in the DC power supply system;

[0098] The phase shift angle calculation module is used to calculate the optimal phase shift angle required by the DC control system and the phase shift angle of each photovoltaic DC converter in the DC power supply system based on the monitoring status of the monitoring module.

[0099] In the DC power supply system, each photovoltaic DC converter is connected in parallel.

[0100] The phase shift angle calculation module calculates the phase shift angle of each photovoltaic DC converter in the following way:

[0101] ,

[0102] in, Indicates the first Phase shift angle of photovoltaic DC converter, This indicates the number of photovoltaic DC converters in the DC power supply system.

[0103] The phase shift angle calculation module calculates the optimal phase shift angle required by the DC control system as follows: ,in This indicates the number of photovoltaic DC converters in the DC power supply system.

[0104] When the photovoltaic DC converter performs uniform phase shifting based on the phase shift angle calculated by the phase shift angle calculation module, the vector sum of the leakage currents of all photovoltaic DC converters is zero, and the combined leakage currents of each photovoltaic DC converter cancel each other out.

[0105] Example 6

[0106] This embodiment describes a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the method for minimizing pooled leakage current adapted to the commissioning and shutdown conditions of photovoltaic DC converters as described in any of embodiments 1-4.

[0107] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0108] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0109] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0110] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0111] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for minimizing the pooled leakage current under photovoltaic DC converter commissioning and shutdown conditions, characterized in that, include: For a DC power supply system composed of multiple photovoltaic DC converters, calculate the optimal phase shift angle for each photovoltaic DC converter to minimize the combined leakage current of the DC power supply system. Monitor the connection status of photovoltaic DC converters in the DC power supply system, and in response to the situation where photovoltaic DC converters are removed or added to the DC power supply system, obtain the number of photovoltaic DC converters after removal or addition. Based on the number of photovoltaic DC converters that are disconnected or added to the grid Recalculate the optimal phase shift angle for each photovoltaic DC converter; Based on the optimal phase shift angle, each photovoltaic DC converter is controlled to perform uniform phase shift, thereby minimizing the leakage current collected in the DC power supply system.

2. The method for minimizing pooled leakage current according to claim 1, characterized in that, Monitoring the access status of photovoltaic DC converters in the DC power supply system includes: polling the heartbeat frames of each photovoltaic DC converter via the communication bus; In response to the detection of a heartbeat frame for a newly added photovoltaic DC-DC converter device ID, the new access event is confirmed to be valid, and the newly added photovoltaic DC-DC converter device ID is updated to the preset photovoltaic DC-DC converter device list; in response to the loss of a heartbeat frame for an existing photovoltaic DC-DC converter device ID, the corresponding photovoltaic DC-DC converter device is considered to have exited, and the corresponding photovoltaic DC-DC converter device information is deleted from the photovoltaic DC-DC converter device list. The number of photovoltaic DC-DC converters to be connected to the DC power supply system in real time is determined based on the updated photovoltaic DC-DC converter equipment list.

3. The method for minimizing pooled leakage current according to claim 2, characterized in that, Monitoring the connection status of the photovoltaic DC converter in the DC power supply system also includes: Obtain the input voltage, input current, output voltage, and output current of the DC branch corresponding to each photovoltaic DC converter, and calculate the input power and output power. When polling the heartbeat frames of each photovoltaic DC converter via the communication bus, if the heartbeat frame of the original photovoltaic DC converter device ID is lost, it is determined whether the electrical quantity criteria are met: whether the input current and output current are both lower than 10% of the corresponding rated current and maintained for more than the set time, and whether the input voltage is maintained above 90% of the port open circuit voltage and maintained for more than the set time. If both the heartbeat frame loss and the electrical quantity criterion are met simultaneously, the corresponding photovoltaic DC converter exit event is deemed valid.

4. The method for minimizing pooled leakage current according to claim 1, characterized in that, In the DC power supply system, each photovoltaic DC converter is connected in parallel.

5. The method for minimizing pooled leakage current according to claim 4, characterized in that, The optimal phase angle of the DC power supply system is: ,in This indicates the number of photovoltaic DC converters with the same switching frequency connected in parallel in the DC power supply system; For all photovoltaic-DC converters connected in parallel with the same switching frequency, the optimal phase shift angle for each photovoltaic-DC converter is calculated using the following formula: ， in, Indicates the first The optimal phase shift angle for a photovoltaic DC-DC converter This indicates the number of photovoltaic DC converters with the same switching frequency that are connected in parallel in the DC power supply system.

6. The method for minimizing pooled leakage current according to claim 1, characterized in that, If all photovoltaic DC converters connected in parallel in a DC power supply system have multiple switching frequencies, then photovoltaic DC converters with the same switching frequency are grouped together. For each photovoltaic DC converter in each group, the optimal phase shift angle is calculated according to the following formula: ， In the formula, Indicates the first The number of photovoltaic DC converters connected in parallel in a DC power supply system at various switching frequencies. For the first The optimal phase shift angle for a photovoltaic DC-DC converter.

7. The method for minimizing pooled leakage current according to claim 6, characterized in that, Also includes: The photovoltaic DC converters at each switching frequency are sorted according to the order in which they are connected to the DC power supply system. After calculating the optimal phase shift angle for each photovoltaic DC converter, the optimal phase shift angles are sequentially sent to the control loop of each photovoltaic DC converter according to the aforementioned order.

8. The method for minimizing pooled leakage current according to claim 7, characterized in that, When a new photovoltaic DC converter is added to the grid, the newly added photovoltaic DC converter will be updated to the end of the original sorting. When a photovoltaic DC-DC converter exits an event, the photovoltaic DC-DC converters in the current connection status are reordered according to their connection time.

9. The method for minimizing pooled leakage current according to claim 1, characterized in that, When the photovoltaic DC converter shifts phase uniformly according to the phase shift angle, the vector sum of the leakage currents of all photovoltaic DC converters is zero, and the combined leakage currents of each photovoltaic DC converter cancel each other out.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the pooled leakage current minimization control method as described in any one of claims 1-9.

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