Power control methods, devices and power conversion systems

Abstract

This application relates to the field of power control, and more particularly to a power control method, device, and power conversion system. The method is applied to a power conversion system including multiple parallel conversion modules. The method includes: obtaining the actual total power value of the power conversion system; when the actual total power value is greater than a predetermined total power reference value, reducing and outputting a branch electrical signal reference value through a first control loop; obtaining the actual branch electrical signal values ​​of each conversion module in the power conversion system; determining target conversion modules based on the fact that the actual branch electrical signal values ​​are greater than the branch electrical signal reference values; and adjusting each target conversion module, with the larger the actual branch electrical signal value, the earlier its actual branch electrical signal value is reduced, until the actual total power value is less than or equal to the total power reference value. This method achieves precise control of the total system power and allows most conversion modules to continue operating within their respective high-efficiency ranges, effectively improving the overall system energy efficiency and capacity utilization.

Description

Technical Field

[0001] This application relates to the field of power control, and more particularly to a power control method, device and power conversion system. Background Technology

[0002] Power conversion systems typically include multiple parallel conversion modules. For example, the photovoltaic energy storage industry often has application scenarios with multiple DC-DC (DC-DC) modules connected in parallel, including multiple parallel MPPT (Maximum Power Point Tracking) modules of photovoltaic inverters, multiple parallel DC-DC energy storage modules, and multiple parallel DC-DC energy storage clusters.

[0003] For the purposes of system thermal management and hardware protection, it is necessary to limit the total power of the system. Currently, independent power limits are usually set for each conversion module. Although this distributed control strategy is simple, it is difficult to accurately limit the total power of the system because each module operates independently, and it is not conducive to improving the overall energy efficiency and capacity utilization of the system. Summary of the Invention

[0004] In view of this, embodiments of this application provide a power control method, apparatus and power conversion system to solve the problem of low power control accuracy in the prior art, which is not conducive to improving the overall energy efficiency and capacity utilization of the system.

[0005] A first aspect of this application provides a power control method applied to a power conversion system including multiple parallel conversion modules, the method comprising:

[0006] Obtain the actual total power value of the power conversion system; When the actual total power value is greater than the predetermined total power reference value, the first control loop reduces and outputs the branch electrical signal reference value. Obtain the actual values ​​of the branch electrical signals of each parallel conversion module in the power conversion system; The target conversion module is determined based on the fact that the actual value of the branch electrical signal is greater than the reference value of the branch electrical signal. Through the adjustment of the second control loop, the branch electrical signal of the target conversion module with the larger actual value is reduced first, until the actual value of the total power is less than or equal to the reference value of the total power.

[0007] In conjunction with the first aspect, in a first possible implementation of the first aspect, reducing and outputting the reference value of the branch electrical signal through the first control loop includes: The first control loop reduces and outputs a reference value for the branch power. Obtaining the actual values ​​of the branch electrical signals of each parallel conversion module in the power conversion system includes: Obtain the actual branch power values ​​of each parallel conversion module in the power conversion system; The target conversion module is determined based on the fact that the actual value of the branch electrical signal is greater than the reference value of the branch electrical signal. Through the adjustment of the second control loop, among the target conversion modules, the one with the larger actual value of the branch electrical signal will have its actual value of the branch electrical signal decrease first, until the actual value of the total power is less than or equal to the reference value of the total power, including: The target conversion module is determined based on the fact that the actual value of the branch power is greater than the reference value of the branch power. Through the adjustment of the second control loop, the branch power of the target conversion module with the larger actual value of the branch power will decrease first, until the actual value of the total power is less than or equal to the reference value of the total power.

[0008] In conjunction with the first aspect, in a second possible implementation of the first aspect, the reference value of the branch electrical signal is reduced and output through the first control loop, including: The first control loop reduces and outputs the branch power reference value, and the branch current reference value of each branch is determined based on the branch power reference value and the voltage of each branch. Obtaining the actual values ​​of the branch electrical signals of each parallel conversion module in the power conversion system includes: Obtain the actual value of the branch current of each parallel branch of the transformation module; The target conversion module is determined based on the fact that the actual value of the branch electrical signal is greater than the reference value of the branch electrical signal. Through the adjustment of the second control loop, among the target conversion modules, the one with the larger actual value of the branch electrical signal will have its actual value of the branch electrical signal decrease first, until the actual value of the total power is less than or equal to the reference value of the total power, including: The target conversion module is determined based on the fact that the actual value of the branch current is greater than the reference value of the branch current. Through the adjustment of the second control loop, the branch current of the target conversion module with the larger actual value is reduced first, until the actual value of the total power is less than or equal to the reference value of the total power.

[0009] In conjunction with the second possible implementation of the first aspect, in the third possible implementation of the first aspect, the branch current reference value of each branch is determined based on the branch power reference value and the voltage of each branch, including: Based on the branch power reference value and the input voltage of the conversion module in each branch, determine the branch current reference value of the conversion module in each branch; or, Based on the branch power reference value and the output voltage of the conversion module of each branch, determine the branch current reference value of the conversion module of each branch.

[0010] In conjunction with the first aspect, in a fourth possible implementation of the first aspect, reducing and outputting the reference value of the branch electrical signal through the first control loop includes: The first control loop includes a first controller, which takes the total power reference value as an instruction and the actual total power value as feedback, and inputs the total power reference value into the first controller. Through the adjustment of the first controller, the reference value of the branch electrical signal is reduced and output.

[0011] In conjunction with the first aspect, in the fifth possible implementation of the first aspect, through the adjustment of the second control loop, the branch electrical signal of the module with the larger actual value decreases first, including: The second control loop includes a second controller. For each target conversion module, the actual value of its branch electrical signal is used as feedback, and the reference value of the branch electrical signal is used as an instruction. The second controller is used to adjust the actual value of the branch electrical signal of the target conversion module, so that the larger the actual value of the branch electrical signal of each target conversion module, the earlier the actual value of its branch electrical signal decreases.

[0012] In conjunction with the first aspect, in a sixth possible implementation of the first aspect, before determining the target transformation module based on the fact that the actual value of the branch electrical signal is greater than the reference value of the branch electrical signal, the method further includes: Obtain the electrical signal limit instructions of each conversion module and determine the electrical signal limit values ​​of each conversion module; The minimum reference value of the branch electrical signal is determined based on the smaller of the defined electrical signal value and the reference value of the branch electrical signal. The target transformation module, which determines that the actual value of the branch electrical signal is greater than the reference value of the branch electrical signal, includes: The target transformation module is determined based on the fact that the actual value of the branch electrical signal is greater than the minimum reference value of the branch electrical signal.

[0013] In conjunction with any one of the first to sixth possible implementations of the first aspect, in the seventh possible implementation of the first aspect, obtaining the actual total power value of the power conversion system includes: The total power of the power conversion system is determined by the sum of the input power of the multiple parallel conversion modules. Alternatively, the total power of the power conversion system can be determined based on the sum of the output power of the multiple parallel conversion modules; Alternatively, the actual total power of the power conversion system can be determined based on the input power of the same inverter module connected in series with the multiple parallel conversion modules.

[0014] A second aspect of this application provides a power control device applied to a power conversion system including multiple parallel conversion modules, the device comprising: A total power actual value acquisition unit is used to acquire the total power actual value of the power conversion system; The branch electrical signal reference value reduction unit is used to reduce and output the branch electrical signal reference value through the first control loop when the actual value of the total power is greater than the predetermined total power reference value; A branch electrical signal actual value acquisition unit is used to acquire the actual values ​​of the branch electrical signals of each parallel conversion module in the power conversion system. The total power actual value adjustment unit is used to determine the target conversion module based on the fact that the actual value of the branch electrical signal is greater than the reference value of the branch electrical signal. Through the adjustment of the second control loop, the branch electrical signal actual value of the target conversion module with the larger actual value is reduced first, until the total power actual value is less than or equal to the total power reference value.

[0015] A third aspect of this application provides a power conversion system, including multiple parallel conversion modules, a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the power conversion system performs the method as described in any of the first aspects.

[0016] A fourth aspect of this application provides a computer program product that, when run on a computer, causes the computer to execute the methods described in the first aspect or its various implementations.

[0017] A fifth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the method as described in any of the first aspects.

[0018] A sixth aspect of this application provides a chip for implementing the methods in the various implementations of the first aspect described above. Specifically, the chip includes a processor for calling and running a computer program from a memory, causing a device equipped with the chip to perform the methods as described in the first aspect or its various implementations.

[0019] The beneficial effects of this application embodiment compared with the prior art are as follows: When performing power control on a power conversion system including multiple parallel conversion modules, if the actual total power of the power conversion system is greater than the total power reference value, the first control loop reduces and outputs the reference value of the branch electrical signal, obtains the actual value of the branch electrical signal of each parallel branch, and determines the target conversion module based on the fact that the actual value of the branch electrical signal is greater than the reference value of the branch electrical signal. Through the adjustment of the second control loop, the branch electrical signal of the target conversion module with the larger actual value is reduced first, until the actual total power is less than or equal to the total power reference value. This achieves precise control of the total power of the system. Furthermore, when avoiding the total power of the system from exceeding the limit, it is achieved by prioritizing the reduction of the actual value of the branch electrical signal of the conversion module with the larger actual value of the branch electrical signal, thereby enabling most conversion modules to continue to operate within their respective high-efficiency range, effectively improving the overall energy efficiency and capacity utilization of the system. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of a string photovoltaic inverter provided in an embodiment of this application; Figure 2 This is a schematic diagram of an energy storage inverter structure provided in an embodiment of this application; Figure 3 This is a schematic diagram of an energy storage inverter structure provided in an embodiment of this application; Figure 4 This is a schematic diagram illustrating the implementation process of a power control method provided in an embodiment of this application; Figure 5 This is a schematic diagram illustrating the calculation of the actual total power value provided in an embodiment of this application; Figure 6 This is a schematic diagram of a control structure provided in an embodiment of this application; Figure 7 This is a schematic diagram of a control loop structure provided in an embodiment of this application; Figure 8 This is a schematic diagram of a control loop structure provided in an embodiment of this application; Figure 9 This is a schematic diagram of a power control process provided in an embodiment of this application; Figure 10 This is a schematic diagram of a power control device provided in an embodiment of this application; Figure 11 This is a schematic diagram of an energy conversion system provided in an embodiment of this application. Detailed Implementation

[0022] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0023] To illustrate the technical solution described in this application, specific embodiments are provided below.

[0024] In power conversion systems, multiple parallel conversion modules, such as multiple parallel DC-DC (DCDC) converter modules, are a common configuration, especially in the field of photovoltaic energy storage. Typical structures include, but are not limited to: multiple parallel MPPT modules in photovoltaic inverters for maximum power point tracking; multiple independent DCDC energy storage modules in parallel in energy storage converters; and energy storage systems composed of multiple battery clusters connected in parallel via independent DCDC modules.

[0025] To achieve thermal management and hardware protection in power conversion systems, it is typically necessary to impose upper limits on the total output or input power of the system. Existing technologies often employ a scheme that sets independent power limits for each conversion module. However, this decentralized control strategy has significant limitations: firstly, due to the lack of a system-level coordination mechanism, it is difficult to achieve precise limiting of the total power; secondly, when the total system power exceeds the limit, all modules are simultaneously and indiscriminately derated, resulting in the idle capacity of lower-power modules, thereby reducing the overall energy efficiency and capacity utilization of the system.

[0026] for example, Figure 1 The diagram shows a typical string photovoltaic inverter, which includes multiple parallel MPPT (Maximum Power Point Tracking) modules (i.e., DC / DC converters in the diagram). Each MPPT module is typically connected to a set of photovoltaic strings, and maximum power point tracking and voltage conversion are performed through an independent DC / DC converter. The outputs of multiple DC / DC converters are connected in parallel and then fed into the inverter module DCAC to convert DC power into AC power for grid connection.

[0027] Figure 2The diagram shows a typical energy storage inverter structure. This inverter comprises multiple parallel-connected battery cells. Each cell is managed for charging and discharging via an independent DC-DC converter module to control voltage and current, thereby reducing imbalances between battery clusters and extending battery life. The DC-DC converter modules are connected in parallel, and their outputs are aggregated to supply the inverter module (DCAC), enabling bidirectional energy flow between DC energy storage and the AC grid.

[0028] Figure 3 The diagram shows a typical energy storage inverter structure. This inverter structure includes multiple battery clusters, each containing multiple cells connected in series. The clusters are then connected in parallel via independent DC-DC converter modules. This design allows for high-power energy storage systems, meeting voltage requirements while simultaneously isolating clusters through the DC-DC converter modules to prevent inter-cluster circulating currents or fault propagation. The DC-DC converter modules independently regulate the power of each cluster, ultimately outputting in parallel to the inverter module (DCAC), enabling bidirectional energy flow between DC energy storage and the AC grid.

[0029] Not limited to Figure 1-3 The power conversion system architecture shown may or may not include an inverter module; furthermore, the conversion module in the power conversion system is not limited to... Figure 1-3 The DC / DC module shown can also be a DC / AC module; that is, multiple parallel converter modules in a power conversion system can also be multiple DC / AC modules connected in parallel. Furthermore, it is not limited to... Figure 1-3 The multi-parallel converter module shown represents the outputs of multiple converter modules connected in parallel. In a power conversion system, the multi-parallel converter module can also have its inputs and outputs connected in parallel, such as the interleaved parallel module in an energy storage system. Alternatively, the multi-parallel converter module can also have its inputs connected in parallel. The power control method proposed in this application is applicable to all the power conversion system architectures described above.

[0030] Figure 4 This application provides a schematic diagram of the implementation process of a power control method, which is applied to a power conversion system including multiple parallel conversion modules. The method includes: In S401, the actual total power value of the power conversion system is obtained.

[0031] The total power actual value in the embodiments of this application refers to the sum of the actual power of multiple parallel converter modules.

[0032] When obtaining the actual value of total power, as shown in the example Figure 5 Taking the power conversion system architecture shown as an example, it can include multiple acquisition methods.

[0033] Method 1: The input power of each converter module (DCDC module in the diagram) can be determined based on its input voltage and current. The total actual power is obtained by summing the input power of all converter modules. The total actual power can be expressed as: P Where PwrSum is the actual total power value, Let be the input voltage of the i-th conversion module. Let be the input current of the i-th conversion module, and n be the number of conversion modules.

[0034] Method 2: If the losses of each conversion module are ignored, the output power of each conversion module can be determined based on its output voltage and output current. Summing the output power of all conversion modules yields the actual total power. The actual total power can be expressed as: Where PwrSum is the actual total power value, This is the bus voltage, because the outputs of each converter module are connected in parallel to the bus (i.e., the DC bus). Therefore, the bus voltage is also the output voltage of each converter module. Let be the output current of the i-th conversion module, and n be the number of conversion modules.

[0035] Method 3: If the losses of each conversion module are ignored, the actual total power of the power conversion system can be determined based on the input power of the same inverter module (DC / AC in the diagram) connected in series with the multiple parallel conversion modules. The actual total power can be expressed as: Where PwrSum is the actual total power value, This is the bus voltage. This is the input current of the inverter module.

[0036] In S402, when the actual value of the total power is greater than the predetermined reference value of the total power, the reference value of the branch electrical signal is reduced and output through the first control loop.

[0037] When the actual total power value is greater than the predetermined total power reference value, it indicates that the current actual total power value is too high and needs to be reduced. In this case, the branch electrical signal reference value is reduced through the first control loop so that the adjusted branch electrical signal reference value can be compared with the actual branch electrical signal values ​​of each conversion module.

[0038] The reference value for the branch electrical signal in the embodiments of this application can be either the branch power reference value or the branch current reference value.

[0039] When the branch electrical signal reference value is the branch power reference value, and the first control loop reduces and outputs the branch electrical signal reference value, it can be done as follows: Figure 6 In the control structure diagram shown, the first control loop includes a first controller, with the total power reference value Pwr_Sum As an instruction, the actual total power value Pwr_Sum is used as feedback and input to the first controller. Through the adjustment of the first controller, the reference value of the branch electrical signal is reduced and output, as shown in the figure, which is the branch power reference value Pwr. .

[0040] The second control loop includes a second controller, using branch electrical signal reference values ​​(such as the branch power reference value Pwr in the diagram). The first controller takes the actual value of the branch electrical signal (such as the actual branch power value Pwr in the figure) as the instruction and the actual value of the branch electrical signal (such as the actual branch power value Pwr in the figure) as feedback. The second controller adjusts the actual value of the branch electrical signal (such as the actual branch power value Pwr in the figure) of the target conversion module. The first controller and the second controller can be, but are not limited to, PID controllers, PI controllers or PD controllers.

[0041] When the branch electrical signal reference value is the branch current reference value, the branch current reference value of each branch can be determined based on the branch power reference value and the branch voltage. For example, the branch power reference value of the i-th branch is Pwr_i. If the input voltage of the converter module in the i-th branch is Uin_i, then the reference value of the branch current in the i-th branch is Curr_i. =Pwr_i / Uin_i.

[0042] In another possible implementation, the branch current reference value of each branch's conversion module can be determined based on the power reference value of each branch and the output voltage of the conversion module in each branch. For example, the branch power reference value of the i-th branch is Pwr_i. If the output voltage of the converter module in the i-th branch is Ubus_i, then the reference value of the branch current in the i-th branch is Curr_i. =Pwr_i / Ubus_i.

[0043] In S403, the actual values ​​of the branch electrical signals of each parallel conversion module in the power conversion system are obtained.

[0044] When obtaining the actual values ​​of the branch electrical signals of each conversion module in a power conversion system, one can obtain the actual values ​​of the branch power of each conversion module, or one can obtain the actual values ​​of the branch current of each conversion module.

[0045] When obtaining the actual branch power value of the converter module, it can be determined by multiplying the input voltage and input current of the converter module. Ignoring converter module losses, the actual branch power value can be determined by the output voltage and output current of the converter module.

[0046] When obtaining the actual value of the branch current of the conversion module, the input current of the conversion module can be determined as the actual value of the branch current of the conversion module, and the output current of the conversion module can also be determined as the actual value of the branch current of the conversion module.

[0047] In S404, a target conversion module is determined based on the fact that the actual value of the branch electrical signal is greater than the reference value of the branch electrical signal. Through the adjustment of the second control loop, the branch electrical signal of the target conversion module with the larger actual value is reduced first, until the actual value of the total power is less than or equal to the reference value of the total power.

[0048] The actual value of the branch electrical signal is compared with the reference value of the branch electrical signal. If the actual value of the branch electrical signal is greater than the reference value, it indicates that the power of the conversion module of that branch is too high, and the power of the conversion module of that branch needs to be adjusted, including reducing the actual value of the branch power of the conversion module or reducing the actual value of the branch current of the conversion module.

[0049] When the reference value of the branch electrical signal is the reference value of the branch power, and the actual value of the branch electrical signal is the actual value of the branch power, one or more target conversion modules can be determined based on the fact that the actual value of the branch power is greater than the reference value of the branch power. Based on the determined target conversion modules, power adjustment is performed through the second control loop, so that the actual value of the branch power of the conversion module with the larger actual value of the branch power decreases first, until the actual value of the total power is less than or equal to the total power reference value.

[0050] When the branch current reference value is the branch current reference value and the actual branch current value is the branch current actual value, the target conversion module can be determined based on the fact that the actual branch current value is greater than the branch current reference value. Through the adjustment of the second control loop, the branch current actual value of each target conversion module with the larger actual branch current value will decrease first, until the total power actual value is less than or equal to the total power reference value.

[0051] The second control loop may include a second controller. When adjusting through the second control loop, for each target conversion module, its branch electrical signal reference value is used as an instruction, and its branch electrical signal actual value is used as feedback, which is input to the second controller corresponding to that target conversion module. The second controller adjusts the actual value of the branch electrical signal of the target conversion module so that, among all target conversion modules, the one with the larger actual value of its branch electrical signal decreases its actual value first.

[0052] When reducing the actual value of the branch electrical signal, the reference value of the branch electrical signal can be gradually reduced. The transformation module whose actual value of the branch electrical signal is greater than the reference value of the branch electrical signal is identified as the target transformation module. The actual value of the branch electrical signal of the target transformation module is adjusted to reduce it, thereby reducing the actual value of the total power until the actual value of the total power is less than or equal to the reference value of the total power.

[0053] When adjusting the actual value of the branch electrical signal of the target conversion module through the second controller, the adjustment can be carried out by means including but not limited to PID controller, PI controller or PD controller. For each target conversion module, the actual value of its branch electrical signal is used as feedback and the reference value of its branch electrical signal is used as instruction. The second controller corresponding to the target conversion module is input, and the adjustment is carried out by means including but not limited to PID adjustment, PI adjustment or PD adjustment, etc., to gradually reduce the actual value of the branch electrical signal of the target conversion module until the actual value of the total power is less than or equal to the reference value of the total power.

[0054] In a possible implementation, before determining the target conversion module based on the actual value of the branch electrical signal being greater than the reference value of the branch electrical signal, this embodiment of the application may also obtain electrical signal limitation instructions for each conversion module and determine the electrical signal limitation value for each conversion module. This electrical signal limitation value may include, for example, a power limitation value or a current limitation value. The electrical signal limitation instructions may be instructions generated based on system safety, system anomalies, or other conditions, or instructions generated based on other control loops.

[0055] Upon receiving an electrical signal limitation command, to enable more reliable system control, the minimum reference value of the branch electrical signal can be determined based on the smaller of the electrical signal limitation value and the branch electrical signal reference value. When determining the target conversion module based on the actual value of the branch electrical signal being greater than its reference value, the target conversion module can be determined based on the actual value of the branch electrical signal being greater than its minimum reference value.

[0056] for example Figure 7 The diagram shown is a schematic of a control loop structure provided in an embodiment of this application. In the first control loop, the total power reference value (PwrSum) is... The reference value of the first control loop (SumPwrLoop) is used as the reference value. At the same time, the actual values ​​of the branch power of all conversion modules, Pwr1, Pwr2, ..., Pwrn, are obtained. The total actual power value (PwrSum) is calculated by the summation module. The total power reference value is used as the instruction and the total actual power value is used as the feedback input to the first controller. When the total actual power value is greater than the total power reference value, the first controller of the first control loop adjusts the value to reduce the branch power reference value and outputs it.

[0057] During the inner loop (second control loop) execution phase, each inner loop receives the same branch power reference value Pwr. It receives power limiting instructions and determines the power limiting value Pwrother1 for each branch. Pwrother2 ... Pwrothern Based on the smaller of the power limit value and the power reference value of each branch, the minimum reference value of the branch power is determined. The minimum reference value of the branch power is used as the reference value of the second control loop of each branch. At the same time, the actual branch power values ​​Pwr1, Pwr2, ..., Pwrn of the conversion module of each branch are obtained. When the actual branch power value is greater than the minimum reference value of the branch power, the conversion module of that branch is determined as the target conversion module. The actual branch power value of the branch where the target conversion module is located is reduced by adjusting the second controller of the corresponding second control loop.

[0058] for example Figure 8 The diagram shown is a schematic of another control loop structure provided in an embodiment of this application. In the first control loop, the total power reference value (PwrSum) The reference value of the first control loop (SumPwrLoop) is used as the reference value. At the same time, the actual values ​​of the branch currents Curr1, Curr2, ..., Currn of all conversion modules are obtained. These values ​​are multiplied by the corresponding branch voltages Ui and then calculated by the summation module to obtain the actual total power value (PwrSum). The total power reference value is used as an instruction and the actual total power value is used as feedback input to the first controller. When the actual total power value is greater than the total power reference value, the first controller of the first control loop adjusts the value to reduce the power and output the branch power reference value.

[0059] During the inner loop (second control loop) execution phase, each inner loop receives the same branch power reference value Pwr. The reference value Curr1 of the branch current of each branch transformation module is calculated by combining the corresponding branch voltage Ui. Curr2 ... Currn Receive current limiting instructions and determine the current limiting value Currother1 for each branch. Currother2 Currothern Based on the smaller of the current limit value and the reference value of the branch current for each branch, the minimum reference value of the branch current is determined. The minimum reference value of the branch current is used as the reference value of the second control loop for each branch. At the same time, the actual values ​​of the branch current Curr1, Curr2, ..., Currn of the conversion module of each branch are collected. When the actual value of the branch current is greater than the minimum reference value of the branch current, the conversion module of that branch is determined as the target conversion module. The actual value of the branch current of the target conversion module is reduced by adjusting the second controller of the corresponding second control loop.

[0060] The first controller and the second controller can be the same controller or different controllers.

[0061] The entire power control process is as follows Figure 9 As shown, assuming the number of parallel converter modules is 3, the actual branch power values ​​of each converter module are Pwr1, Pwr2, and Pwr3, respectively, and the total power reference value is Pwr_Sum. The actual total power value is Pwr_Sum, and the reference value of the branch power output from the first control loop is Pwr. At time t0, due to the increased power of the converter module in the first branch, the actual total power value Pwr_Sum begins to increase. At time t1, the actual total power value Pwr_Sum equals the reference total power value Pwr_Sum. After t1, as the actual total power value Pwr_Sum continues to increase, the actual total power value Pwr_Sum becomes greater than the reference total power value Pwr_Sum. The first control loop reduces and outputs the branch power reference value Pwr (Similarly, the actual value of the branch current can also be calculated from the branch voltage for current comparison.) At time t2, the reference value of the branch power Pwr Similar to the actual power value Pwr1 of the first branch, after t2, since the actual total power value Pwr_Sum is still greater than the reference total power value Pwr_Sum... The reference value of the branch power output by the first control loop, Pwr Continue to decrease. Because the actual power value Pwr1 of the first branch is greater than the reference power value Pwr of the branch. By adjusting the second control loop, the actual power value of the first branch is reduced, thereby decreasing the actual power value of the first branch.

[0062] When the actual power value of the first branch decreases to time t3, the actual total power value Pwr_Sum equals the reference total power value Pwr_Sum. At this point, the branch power reference value output by the first control loop no longer decreases. Therefore, through the adjustment of the second control loop, the actual power value of the first branch, following the branch power reference value, also no longer decreases, thus completing the automatic adjustment of the system power. Throughout this process, the actual power values ​​of the conversion modules of the second and third branches, namely the second actual power value Pwr2 and the third actual power value Pwr3, are always less than the branch power reference value Pwr. Therefore, the second control loop corresponding to the conversion modules of the second and third branches will not be adjusted to reduce the actual values ​​of the second and third power, so that the conversion modules of the second and third branches can maintain the original power output.

[0063] In summary, during the entire power control and regulation process, the reference value of the branch electrical signal gradually decreases, and priority is given to optimizing the power of branches with larger actual values ​​of branch electrical signals. This not only achieves precise control of the total system power, but also allows most conversion modules to continue operating within their respective high-efficiency ranges, thereby improving the overall energy efficiency of the system and the capacity utilization rate.

[0064] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0065] Figure 10 This is a schematic diagram of a power control device provided in an embodiment of this application. The device is applied to a power conversion system including multiple parallel conversion modules. The device includes: The total power actual value acquisition unit 1001 is used to acquire the total power actual value of the power conversion system.

[0066] The branch electrical signal reference value reduction unit 1002 is used to reduce and output the branch electrical signal reference value through a first control loop when the actual value of the total power is greater than a predetermined total power reference value.

[0067] The branch electrical signal actual value acquisition unit 1003 is used to acquire the actual values ​​of the branch electrical signals of each conversion module connected in parallel in the power conversion system.

[0068] The total power actual value adjustment unit 1004 is used to determine the target conversion module based on the fact that the actual value of the branch electrical signal is greater than the reference value of the branch electrical signal. Through the adjustment of the second control loop, the branch electrical signal actual value of the target conversion module with the larger actual value is reduced first, until the total power actual value is less than or equal to the total power reference value.

[0069] Figure 10The power control device shown is, and Figure 4 The power control method shown corresponds to this.

[0070] Figure 11 This is a schematic diagram of a power conversion system provided in an embodiment of this application. Figure 11 As shown, the power conversion system 11 of this embodiment includes: multiple parallel conversion modules (not shown in the figure), a processor 110, a memory 111, and a computer program 112, such as a power control program, stored in the memory 111 and executable on the processor 110. When the processor 110 executes the computer program 112, it implements the steps in the various power control method embodiments described above. Alternatively, when the processor 110 executes the computer program 112, it implements the functions of each module / unit in the various device embodiments described above.

[0071] For example, the computer program 112 may be divided into one or more modules / units, which are stored in the memory 111 and executed by the processor 110 to complete this application. The one or more modules / units may be a series of computer program instruction segments capable of performing specific functions, which describe the execution process of the computer program 112 in the power conversion system 11.

[0072] The power conversion system may include, but is not limited to, a processor 110 and a memory 111. Those skilled in the art will understand that... Figure 11 This is merely an example of a power conversion system 11 and does not constitute a limitation on the power conversion system 11. It may include more or fewer components than shown, or combine certain components, or different components. For example, the power conversion system may also include input / output devices, network access devices, buses, etc.

[0073] The processor 110 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0074] The memory 111 can be an internal storage unit of the power conversion system 11, such as a hard disk or memory of the power conversion system 11. The memory 111 can also be an external storage device of the power conversion system 11, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., equipped on the power conversion system 11. Furthermore, the memory 111 can include both internal storage units and external storage devices of the power conversion system 11. The memory 111 is used to store the computer program and other programs and data required by the power conversion system. The memory 111 can also be used to temporarily store data that has been output or will be output.

[0075] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0076] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0077] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0078] In the embodiments provided in this application, it should be understood that the disclosed devices / terminal equipment and methods can be implemented in other ways. For example, the device / terminal equipment embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling or direct coupling or communication connection may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0079] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0080] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0081] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by hardware related to computer program instructions. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0082] In addition, this application also provides a computer program product that, when run on a computer, causes the computer to execute the methods in the above-described implementations.

[0083] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application 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. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A power control method, characterized in that, The method is applied to a power conversion system including multiple parallel conversion modules, and the method includes: Obtain the actual total power value of the power conversion system; When the actual total power value is greater than the predetermined total power reference value, the first control loop reduces and outputs the branch electrical signal reference value. Obtain the actual values ​​of the branch electrical signals of each parallel conversion module in the power conversion system; The target conversion module is determined based on the fact that the actual value of the branch electrical signal is greater than the reference value of the branch electrical signal. Through the adjustment of the second control loop, the branch electrical signal of the target conversion module with the larger actual value is reduced first, until the actual value of the total power is less than or equal to the reference value of the total power.

2. The method according to claim 1, characterized in that, The reference value of the branch electrical signal is reduced and output through the first control loop, including: The first control loop reduces and outputs a reference value for the branch power. Obtaining the actual values ​​of the branch electrical signals of each parallel conversion module in the power conversion system includes: Obtain the actual branch power values ​​of each parallel conversion module in the power conversion system; The target conversion module is determined based on the fact that the actual value of the branch electrical signal is greater than the reference value of the branch electrical signal. Through the adjustment of the second control loop, among the target conversion modules, the one with the larger actual value of the branch electrical signal will have its actual value of the branch electrical signal decrease first, until the actual value of the total power is less than or equal to the reference value of the total power, including: The target conversion module is determined based on the fact that the actual value of the branch power is greater than the reference value of the branch power. Through the adjustment of the second control loop, the branch power of the target conversion module with the larger actual value of the branch power will decrease first, until the actual value of the total power is less than or equal to the reference value of the total power.

3. The method according to claim 1, characterized in that, The reference value of the branch electrical signal is reduced and output through the first control loop, including: The first control loop reduces and outputs the branch power reference value, and the branch current reference value of each branch is determined based on the branch power reference value and the voltage of each branch. Obtaining the actual values ​​of the branch electrical signals of each parallel conversion module in the power conversion system includes: Obtain the actual value of the branch current of each parallel branch of the transformation module; The target conversion module is determined based on the fact that the actual value of the branch electrical signal is greater than the reference value of the branch electrical signal. Through the adjustment of the second control loop, among the target conversion modules, the one with the larger actual value of the branch electrical signal will have its actual value of the branch electrical signal decrease first, until the actual value of the total power is less than or equal to the reference value of the total power, including: The target conversion module is determined based on the fact that the actual value of the branch current is greater than the reference value of the branch current. Through the adjustment of the second control loop, the branch current of the target conversion module with the larger actual value is reduced first, until the actual value of the total power is less than or equal to the reference value of the total power.

4. The method according to claim 3, characterized in that, Based on the branch power reference value and the voltage of each branch, determine the branch current reference value for each branch, including: Based on the branch power reference value and the input voltage of the conversion module in each branch, determine the branch current reference value of the conversion module in each branch; or, Based on the branch power reference value and the output voltage of the conversion module of each branch, determine the branch current reference value of the conversion module of each branch.

5. The method according to claim 1, characterized in that, The reference values ​​for reducing and outputting the branch electrical signal through the first control loop include: The first control loop includes a first controller, which takes the total power reference value as an instruction and the actual total power value as feedback, and inputs the total power reference value into the first controller. Through the adjustment of the first controller, the reference value of the branch electrical signal is reduced and output.

6. The method according to claim 1, characterized in that, Through the adjustment of the second control loop, in each target transformation module, the branch with the larger actual value of the branch electrical signal will have its actual value decrease first, including: The second control loop includes a second controller. For each target conversion module, the actual value of its branch electrical signal is used as feedback, and the reference value of the branch electrical signal is used as an instruction. The second controller is used to adjust the actual value of the branch electrical signal of the target conversion module, so that the larger the actual value of the branch electrical signal of each target conversion module, the earlier the actual value of its branch electrical signal decreases.

7. The method according to claim 1, characterized in that, Before determining the target transformation module based on the fact that the actual value of the branch electrical signal is greater than the reference value of the branch electrical signal, the method further includes: Obtain the electrical signal limit instructions of each conversion module and determine the electrical signal limit values ​​of each conversion module; The minimum reference value of the branch electrical signal is determined based on the smaller of the defined electrical signal value and the reference value of the branch electrical signal. The target transformation module, which determines that the actual value of the branch electrical signal is greater than the reference value of the branch electrical signal, includes: The target transformation module is determined based on the fact that the actual value of the branch electrical signal is greater than the minimum reference value of the branch electrical signal.

8. The method according to any one of claims 1-7, characterized in that, Obtaining the actual total power value of the power conversion system includes: The total power of the power conversion system is determined by the sum of the input power of the multiple parallel conversion modules. Alternatively, the total power of the power conversion system can be determined based on the sum of the output power of the multiple parallel conversion modules; Alternatively, the actual total power of the power conversion system can be determined based on the input power of the same inverter module connected in series with the multiple parallel conversion modules.

9. A power control device, characterized in that, The device is applied to a power conversion system including multiple parallel conversion modules, and the device includes: A total power actual value acquisition unit is used to acquire the total power actual value of the power conversion system; The branch electrical signal reference value reduction unit is used to reduce and output the branch electrical signal reference value through the first control loop when the actual value of the total power is greater than the predetermined total power reference value; A branch electrical signal actual value acquisition unit is used to acquire the actual values ​​of the branch electrical signals of each parallel conversion module in the power conversion system. The total power actual value adjustment unit is used to determine the target conversion module based on the fact that the actual value of the branch electrical signal is greater than the reference value of the branch electrical signal. Through the adjustment of the second control loop, the branch electrical signal actual value of the target conversion module with the larger actual value is reduced first, until the total power actual value is less than or equal to the total power reference value.

10. A power conversion system, comprising multiple parallel conversion modules, a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it causes the power conversion system to implement the method as described in any one of claims 1-8.

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