Control method, system and equipment of multi-machine parallel direct current converter and storage medium

Abstract

The invention relates to the technical field of electric power control, in particular to a control method, system and device of a multi-machine parallel direct current converter and a storage medium, and is used for controlling a plurality of direct current converters connected in parallel in an energy storage system. Selecting one of the direct-current converters in the normal working state as a new host, and using the other direct-current converters as slaves; taking the total system reference value released by the old host in the previous period as the initial value of the voltage loop integral quantity of the new host, executing current and voltage double-closed-loop control, and releasing the voltage loop output of the new host as the total system reference value of the current period; and according to the total system reference value issued by the new host in the current period and the state parameters of the energy storage units corresponding to the direct-current converters in the current period, calculating to obtain the reference power of the direct-current converters. According to the invention, the bus voltage can be kept stable and the continuity of load power distribution can be ensured in the master-slave switching process, so that the system can operate stably.

Description

Technical Field

[0001] This application relates to the field of power control technology, and in particular to a control method, system, device and storage medium for a multi-machine parallel DC-DC converter. Background Technology

[0002] In modern energy storage systems, to meet the demands of large capacity and high reliability, multiple DC-DC converters are often connected in parallel to work together, achieving power sharing and system redundancy. Parallel control methods are mainly divided into master-slave control and peer-to-peer control. In the existing master-slave control method, one DC-DC converter is designated as the master, responsible for calculating global system parameters and issuing control commands. The remaining DC-DC converters act as slaves, only executing power or current commands issued by the master. The master performs voltage / current dual closed-loop control, while the slaves only perform current loop following. When the master fails and a switchover is required, the new master re-establishes the control loop based on its currently detected bus voltage and current, and starts executing current / voltage dual closed-loop control from the initial state. This control method can centrally manage the system's operating status, improve control accuracy and the coordination consistency of each DC-DC converter, thereby ensuring the stability of bus voltage and system power under steady-state and dynamic conditions.

[0003] However, in the master-slave control process of multiple DC-DC converters in parallel, when the master converter fails and needs to be switched over, the new master converter needs to re-establish voltage / current dual closed-loop control from the initial state. Since the slave converter only performs current loop following before the switchover and lacks the ability to regulate the bus voltage, the establishment of its control loop is not continuous at the moment the new master converter takes over control. Temporary fluctuations in voltage and current control quantities will occur, causing instantaneous deviations in bus voltage and output power. This may affect the overall steady-state performance and load distribution of the system, thus causing the system to be unable to maintain stable operation. Summary of the Invention

[0004] This application provides a control method, system, device, and storage medium for a multi-machine parallel DC-DC converter, which can maintain bus voltage stability and ensure the continuity of load power distribution during master-slave switching, thus enabling the overall system to maintain stable operation. This application provides the following technical solutions: In a first aspect, this application provides a control method for a multi-machine parallel DC-DC converter, used to control multiple DC-DC converters connected in parallel in an energy storage system. The control method includes the following steps: When the system is powered on for the first time or when the existing master fails, one of the DC converters that are in normal working condition is selected as the new master, and the other DC converters that are in normal working condition are selected as slaves. The system total reference value published by the old host in the previous cycle is used as the initial value of the voltage loop integral of the new host, and the new host is made to perform current and voltage dual closed-loop control. The voltage loop output of the new host is published to the outside as the system total reference value of the current cycle. Based on the total system reference value released by the new host in the current cycle and the state parameters of the energy storage units corresponding to each DC converter in the current cycle, the reference power of each DC converter is calculated.

[0005] In one specific implementation scheme, the step of calculating the reference power of each DC-DC converter based on the total system reference value published by the new host in the current period and the state parameters of the energy storage units corresponding to each DC-DC converter in the current period includes the following steps: Obtain the status parameters of the energy storage units corresponding to all DC-DC converters in normal operating condition. The status parameters include the SOC value and the SOP limit value. Based on the state parameters of the energy storage units corresponding to each DC-DC converter, the power allocation ratio of each DC-DC converter is determined. The power allocation ratio of each DC-DC converter is directly proportional to the SOC value of the corresponding energy storage unit when the corresponding energy storage unit is in the discharge state, and inversely proportional to the SOC value of the corresponding energy storage unit when the corresponding energy storage unit is in the charging state. The reference current of each DC converter is calculated based on the total system reference value and the power allocation ratio of each DC converter released by the new host, and the power of the reference current is calculated in combination with the DC bus voltage to obtain the reference power of each DC converter.

[0006] In one specific implementation scheme, determining the power allocation ratio of each DC-DC converter based on the state parameters of the energy storage unit corresponding to each DC-DC converter includes the following steps: The SOC values ​​of the corresponding energy storage units of all DC-DC converters in normal operating condition are summed to obtain the accumulated SOC value. When the energy storage unit corresponding to each DC-DC converter is in a discharging state, the ratio of the SOC value of the energy storage unit to the accumulated SOC value is used as the power allocation ratio of the DC-DC converter corresponding to that energy storage unit.

[0007] In one specific implementation scheme, determining the power allocation ratio of each DC-DC converter based on the state parameters of the energy storage unit corresponding to each DC-DC converter further includes the following steps: When the energy storage unit corresponding to each DC converter is in the charging state, the energy storage units corresponding to all DC converters in normal working state are sorted from low to high according to the SOC value to obtain the ranking index of each energy storage unit. The ranking index starts counting from zero. Based on the SOC value corresponding to the ranking index of each energy storage unit and the accumulated SOC value, the power allocation ratio of each DC converter is determined according to the following formula. : ; in, For the first Power allocation ratio of each DC-DC converter This represents the number of energy storage units corresponding to a DC-DC converter in normal operating condition. For the first Ranking index of energy storage units corresponding to each DC-DC converter. Indicates the first The SOC value corresponding to each index position. This is the accumulated value of the SOC.

[0008] In one specific implementation scheme, when the reference power of a DC-DC converter exceeds the SOP limit of its corresponding energy storage unit, the excess reference power is allocated to other DC-DC converters that are in normal operating condition for compensation.

[0009] In one specific implementation scheme, the step of selecting a new master converter from those in normal working condition when the system is first powered on or when an existing master converter fails includes: When the system is powered on for the first time, the operating status of all parallel DC-DC converters is polled and detected. One of the DC-DC converters that is in normal operating status in two consecutive detection cycles is selected as the new master. When the existing host fails, the operating status of all parallel DC-DC converters is polled and detected, and one of the DC-DC converters that is in normal working condition in one detection cycle is selected as the new host.

[0010] In one specific implementation, in the step of polling and detecting the operating status of all parallel DC-DC converters when the system is first powered on, and selecting one of the DC-DC converters that are in normal operating status in two consecutive detection cycles as the new master, if the same DC-DC converter in normal operating status is selected in two consecutive detection cycles, that DC-DC converter is selected as the new master.

[0011] Secondly, this application provides a control system for a multi-machine parallel DC-DC converter, used to control multiple DC-DC converters connected in parallel in an energy storage system, the control system comprising: The master selection module is used to select one DC-DC converter that is in normal working condition as the new master when the system is powered on for the first time or when the existing master fails, and the other DC-DC converters that are in normal working condition are used as slaves. The host inheritance module is used to take the total system reference value published by the old host in the previous cycle as the initial value of the voltage loop integral of the new host, and enable the new host to perform current and voltage dual closed-loop control, and publish the voltage loop output of the new host as the total system reference value of the current cycle. The power allocation module is used to calculate the reference power of each DC converter based on the total system reference value released by the new host in the current cycle and the state parameters of the energy storage units corresponding to each DC converter in the current cycle.

[0012] Thirdly, this application provides an electronic device including a processor and a memory, wherein the memory stores a program that is loaded and executed by the processor to implement the control method for a multi-machine parallel DC-DC converter as described above.

[0013] Fourthly, this application provides a computer-readable storage medium storing a program that, when executed by a processor, is used to implement the control method for a multi-machine parallel DC-DC converter as described above.

[0014] When the system is first powered on or the existing master fails, a DC-DC converter in normal operation is selected as the new master. The total system reference value published by the old master in the previous cycle is used as the initial value of the voltage loop integral of the new master, enabling the new master to smoothly execute current / voltage dual closed-loop control when taking over control. By publishing the voltage loop output of the new master as the total system reference value for the current cycle, each slave calculates the reference power based on the total system reference value and the state parameters of its corresponding energy storage unit in the current cycle, thereby achieving power coordination and balanced distribution among the DC-DC converters. Compared with the existing master-slave control method, the new master does not need to establish a control loop from scratch. Instead, it directly inherits the total system reference value published by the old master in the previous cycle as the initial value of the voltage loop integral, allowing the voltage loop to smoothly inherit the existing control information from the original master's operating state. Based on this, current / voltage dual closed-loop control is executed to achieve a smooth transition of control quantities, thus minimizing the sudden changes in voltage and current during master switching. Therefore, the new master can maintain the stability of the bus voltage and ensure the continuity of load power distribution during master-slave switching, ensuring the overall stable operation of the system.

[0015] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, the preferred embodiments of this application are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0016] Figure 1 This is a structural block diagram of the energy storage system in the embodiments of this application.

[0017] Figure 2This is a flowchart illustrating the control method for a multi-machine parallel DC-DC converter in an embodiment of this application.

[0018] Figure 3 This is a flowchart illustrating step S103 in an embodiment of this application.

[0019] Figure 4 This is a schematic diagram of the host selection process in an embodiment of this application.

[0020] Figure 5 This is a block diagram of the control system of the multi-machine parallel DC-DC converter in the embodiments of this application.

[0021] Figure 6 This is a block diagram of the electronic device controlling the multi-machine parallel DC-DC converter in the embodiments of this application. Detailed Implementation

[0022] The specific embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but are not intended to limit the scope of this application.

[0023] This application provides a control method for a multi-machine parallel DC-DC converter, used to control multiple DC-DC converters connected in parallel in an energy storage system, referring to... Figure 1 The diagram below shows the structural block diagram of the energy storage system in this embodiment. Multiple DC-DC converters connected in parallel are connected to the energy storage units and connected to the bus to achieve energy integration and coordinated output among the energy storage units. The DC-DC converters communicate with each other through the mCAN bus to synchronize control information. In one embodiment, the energy storage unit is a battery.

[0024] Optionally, in this embodiment, the mCAN bus is used as the communication bus between all parallel DC-DC converters. Alternatively, CAN bus, Modbus bus, EtherCAT bus, or other communication buses suitable for energy storage system control information transmission may be used. This application does not limit the specific type of communication bus.

[0025] Reference Figure 2 This is a flowchart illustrating a control method for a multi-machine parallel DC-DC converter according to an embodiment of this application. The control method includes at least the following steps: Step S101: When the system is powered on for the first time or when the existing host fails, select one of the DC converters that are in normal working condition as the new host, and the other DC converters that are in normal working condition as slaves.

[0026] In step S101, the operating states of the DC-DC converter include standby, soft start, fault, and normal operation, where standby, soft start, and fault states are all considered abnormal operating states. When the system is powered on for the first time, the operating states of all parallel DC-DC converters are polled, and one DC-DC converter that has been in normal operation for two consecutive detection cycles is selected as the new master converter. When the existing master converter fails, the operating states of all parallel DC-DC converters are polled, and one DC-DC converter that has been in normal operation for one detection cycle is selected as the new master converter.

[0027] Specifically, when the system powers on for the first time, it first checks whether all parallel DC-DC converters have completed one round of testing. If not, the operating status of all parallel DC-DC converters is polled, and the lowest-numbered converter among those in normal operating condition is selected as the candidate master. If one round of testing has been completed, a second round of testing is performed. The DC-DC converter with the lowest number in normal operating condition during the second round is selected and recorded as the current DC-DC converter. It is then checked whether the current DC-DC converter matches the candidate master selected in the previous round. If they match, the current DC-DC converter is selected as the master. If they do not match, the current DC-DC converter is updated as the candidate master, and a new round of testing continues until the DC-DC converter selected in the new round matches the candidate master. It should be noted that using at least two rounds of testing during the system's first power-on is to avoid inconsistent master selection results due to differences in the status judgment of different DC-DC converters during a single testing process. By confirming that the same DC-DC converter is in normal working condition in two consecutive testing cycles, the selection of the new host can be effectively guaranteed to be unique and consistent, thereby avoiding the election conflict caused by multiple DC-DC converters being judged as candidate hosts at the same time.

[0028] When the existing master converter fails, the operating status of all parallel DC-DC converters is polled and monitored in one monitoring cycle. Among the DC-DC converters operating normally in one monitoring cycle, the one with the lowest number is selected as the new master converter, and the remaining DC-DC converters operating normally become slave converters. It should be noted that only one monitoring cycle is needed to determine the new master converter when the existing master converter fails because the operating status of all parallel DC-DC converters has been updated in the previous stage before the master converter fails. At this point, the system can make a judgment directly based on the latest status information. Furthermore, to complete the selection of the new master converter in the shortest possible time and avoid control loop failure due to prolonged master converter absence, a single monitoring cycle enables rapid switching, thereby ensuring the continuous and stable operation of the system.

[0029] Optionally, in this embodiment, the DC-DC converter with the lowest number is selected as the new host after polling detection. Alternatively, the selection can be made based on other conditions, such as selecting the new host based on the various parameters of the DC-DC converter. This application does not impose any restrictions on the specific method of selecting the new host.

[0030] Step S102: Use the total system reference value published by the old host in the previous cycle as the initial value of the voltage loop integral of the new host, and make the new host perform current and voltage dual closed-loop control, and publish the voltage loop output of the new host as the total system reference value of the current cycle.

[0031] In step S102, to ensure a smooth transition of the control loop during master-slave switching, the control modes of the new master and the remaining slaves need to be adjusted. Specifically, when the master switching flag is detected to be set, the system determines that a master-slave switching operation is required. After selecting the new master in the manner described in step S101, the new master switches from its original working mode of only performing current loop control as a slave to simultaneously performing dual closed-loop control of both the voltage loop and the current loop. To avoid a sudden change in the voltage loop output during master-slave switching, the new master inherits the system total reference value published by the old master in the previous cycle and uses it as the initial value of its own voltage loop integral, allowing the voltage loop to run continuously based on existing control results, rather than rebuilding the loop from scratch. Subsequently, the new master generates a new voltage loop output value based on the voltage / current dual-loop calculation results and publishes this voltage loop output value externally via the mCAN bus in the current cycle as the new system total reference value.

[0032] Meanwhile, the other slave devices operating normally need to synchronously update their controlled objects, switching from receiving the old master's system reference value to receiving the new master's system reference value published in the current cycle. This process ensures the continuity of the control loop during master-slave switching, preventing voltage and current control values ​​from jumping during the switch, thus guaranteeing the stability and continuity of bus voltage and system power distribution.

[0033] Step S103: Calculate the reference power of each DC converter based on the total system reference value released by the new host in the current cycle and the state parameters of the energy storage units corresponding to each DC converter in the current cycle.

[0034] Reference Figure 3 The diagram below illustrates step S103 in an embodiment of this application. The method includes at least the following steps: Step S1031: Obtain the status parameters of the energy storage units corresponding to all DC-DC converters in normal operating condition. The status parameters include the SOC value and the SOP limit value.

[0035] In step S1031, after the new host selects and publishes the system's total reference value to the outside world through the mCAN bus, it collects the status parameters of the energy storage units corresponding to all DC-DC converters that are in normal working condition through the mCAN bus. The status parameters include the SOC value and SOP limit of the energy storage unit.

[0036] Step S1032: Based on the state parameters of the energy storage units corresponding to each DC-DC converter, determine the power allocation ratio of each DC-DC converter. The power allocation ratio of each DC-DC converter is directly proportional to the SOC value of the corresponding energy storage unit when the corresponding energy storage unit is in a discharging state, and inversely proportional to the SOC value of the corresponding energy storage unit when the corresponding energy storage unit is in a charging state.

[0037] Specifically, the SOC values ​​of the corresponding energy storage units of all DC-DC converters in normal working condition are summed to obtain the accumulated SOC value. When the energy storage unit corresponding to each DC-DC converter is in the discharge state, the ratio of the SOC value of the energy storage unit to the accumulated SOC value is used as the power allocation ratio of the DC-DC converter corresponding to that energy storage unit.

[0038] When the energy storage units corresponding to each DC-DC converter are in the charging state, all energy storage units corresponding to all DC-DC converters in normal operation are sorted from low to high according to their State of Charge (SOC) values, resulting in a ranking index for each energy storage unit, starting from zero. Then, based on the SOC value corresponding to each energy storage unit's ranking index and the accumulated SOC value, the power allocation ratio of each DC-DC converter is determined according to the following formula. : ; in, For the first Power allocation ratio of each DC-DC converter This represents the number of energy storage units corresponding to a DC-DC converter in normal operating condition. For the first Ranking index of energy storage units corresponding to each DC-DC converter. Indicates the first The SOC value corresponding to each index position. This is the accumulated SOC value.

[0039] Step S1033: Calculate the reference current of each DC converter based on the total system reference value and power allocation ratio value released by the new host, and calculate the power of the reference current in combination with the DC bus voltage to obtain the reference power of each DC converter.

[0040] Specifically, the reference current of the DC-DC converter The calculation formula is as follows: ; in, Total system reference values ​​released for the new host.

[0041] Reference power of DC-DC converter The calculation formula is as follows: ; in, This is the DC bus voltage.

[0042] Step S1034: When the reference power of a DC-DC converter exceeds the SOP limit of its corresponding energy storage unit, the excess reference power is allocated to other DC-DC converters that are in normal working condition for compensation.

[0043] Specifically, if the reference power of a parallel DC-DC converter corresponding to an energy storage unit exceeds its safe operating power limit, i.e., the SOP limit, then the DC-DC converter will only operate according to the SOP limit, and the excess power demand will be shared and compensated by other DC-DC converters that are in normal operating condition. In this way, the risk of overload due to a single energy storage unit exceeding its safe operating power is avoided, while ensuring that the overall power demand of the system is met.

[0044] In the entire power allocation process of step S103, reference power is allocated only to DC-DC converters in normal operating condition. Therefore, even if one or more slave devices fail during operation, it will not affect the overall power allocation and normal operation of the system, further improving the robustness and reliability of the system. Furthermore, for energy storage systems, from the perspectives of system safety, operating efficiency, and battery life, the ideal state is for multiple parallel energy storage units to maintain a consistent State of Charge (SOC), allowing each unit to be charged and discharged synchronously, avoiding situations where one unit is depleted while others still have significant capacity. If charging and discharging power is allocated solely based on SOC, the bus stability may be compromised due to SOP limits, potentially damaging battery units. Conversely, if power allocation is based solely on SOP, SOC imbalance will occur, shortening the system's lifespan. The power allocation method proposed in this step considers both SOC and SOP parameters during power allocation, achieving a balance between safety and balance. This allows the system to meet power requirements and bus stability while extending the lifespan of energy storage units and improving the overall operating efficiency and stability of the system.

[0045] The following describes the master selection method in the control method for multi-parallel DC-DC converters provided in this embodiment using a specific example. In this embodiment, to achieve status monitoring and master selection of the parallel DC-DC converters, the system uses a polling method to detect the operating status of each DC-DC converter. The polling method refers to each DC-DC converter sequentially sending its own information frame on the communication bus according to its number. For example, when DC-DC converters A, B, and C exist, DC-DC converter B, after receiving the information frame from DC-DC converter A, then sends its own information frame; DC-DC converter C, after receiving the information frame from DC-DC converter B, then sends its own information frame, and so on, until all DC-DC converters have completed one information transmission, achieving status updates and synchronization for all DC-DC converters. Through this polling mechanism, the system can ensure that each DC-DC converter obtains complete parallel status information, thereby providing a reliable data foundation for subsequent master selection.

[0046] In order to efficiently manage and store the status information of each DC-DC converter during the polling test, this application uses a ModInfo array to carry the status information of each DC-DC converter. An example of the ModInfo array is a three-row, N-column structure ModInfo[3][N], where N represents the number of parallel modules. The first row of the array stores the number of each DC-DC converter, the second row stores the SOC value of the corresponding energy storage unit of the DC-DC converter, and the third row stores the working status bit of each DC-DC converter, where 0 indicates that the DC-DC converter is in normal working state and 1 indicates that the DC-DC converter is in abnormal state. In each round of polling test, the DC-DC converter sends its own number, the SOC value of the corresponding energy storage unit and the working status bit to the bus and updates the ModInfo array, so that all DC-DC converters can obtain the information of the entire parallel system in a timely manner.

[0047] Optionally, the ModInfo array used in this embodiment is only one optional data structure form. Other data structures or methods can also be used to store and transmit the number, SOC value and status information of each DC-DC converter. This application does not impose any restrictions on the form of the data structure.

[0048] Figure 4The diagram illustrates the host selection process in this embodiment. First, it checks if the initial entry flag is 0. The initial entry flag indicates whether this is the first time the host selection process has been executed. If the initial entry flag is not 0, it means the system has completed at least one host selection, and the process enters the regular host check phase. The system first checks the current host's status in the ModInfo array. Since array indices start from 0, and DC-DC converter numbers start from 1, "host ID-1" is used to retrieve the array element corresponding to the current host. If the ModInfo[host ID-1] status value is 1, it indicates the current host is in an abnormal working state, and a new host needs to be selected; if the status value is 0, it indicates the current host is still normal, and the process ends directly without changing the host.

[0049] When a new master converter needs to be selected, the system initializes counter i to 0 and loops to check the status of each DC-DC converter for N loops, where N is the number of DC-DC converters connected in parallel. In each loop, the system checks if ModInfo[i] is 0 (i.e., the DC-DC converter is in normal operating condition). If ModInfo[i] is not 0, it returns to the initial operation and continues polling the next DC-DC converter; if ModInfo[i] is 0, the DC-DC converter number is set as the new master converter ID. Then, it checks if the master converter ID matches the DC-DC converter number currently being executed. If they match, it means the current DC-DC converter has been selected as the new master converter. In this case, the master converter change flag is set to notify other DC-DC converters that a master switch has occurred. Simultaneously, the voltage loop reset flag is set to ensure that the new master converter can correctly initialize the voltage loop integral when taking over control, smoothly transitioning to voltage / current dual closed-loop control. After completing these operations, the DC-DC converter exits the master converter selection loop, and the current master selection process ends. If there is a discrepancy, it means that the current DC-DC converter is not the selected host. In this case, the current DC-DC converter does not need to perform host-related initialization operations or set the flag bit. The current DC-DC converter directly exits the loop and ends the current host selection process, waiting for the control command of the new host.

[0050] If the initial entry flag is 0, it indicates that the system has not yet completed the host selection process, corresponding to the system's first power-on. At this time, the system first determines whether a communication cycle has been completed. If not, the process ends directly, waiting for the next round of polling. After completing a communication cycle, the system initializes counter i to 0 and cyclically checks the operating status of each DC-DC converter according to its number. For DC-DC converters with a status value of 0, i.e., those in normal operating condition, the system further determines whether their number matches the LastHostID recorded in the previous round. LastHostID is used to record the number of the candidate host in the previous round of detection, so as to determine whether the same DC-DC converter continues to be in normal condition in two consecutive rounds of detection. If the current DC-DC converter number matches LastHostID, the DC-DC converter is identified as the host, the initial entry flag is set to 1, and LastHostID is updated to the current DC-DC converter number; if they do not match, LastHostID is updated to the current DC-DC converter number, the loop exits, and the current round of host selection process ends. Through this two-round detection mechanism, the system can avoid inconsistencies in the selection of the host by different DC converters, thereby ensuring that the host selected is unique and stable during the first power-on or host switching.

[0051] In summary, by selecting one of the DC-DC converters in normal operation as the new master converter when the system is first powered on or when the existing master converter fails, and using the total system reference value published by the old master converter in the previous cycle as the initial value of the voltage loop integral of the new master converter, the new master converter can smoothly execute current / voltage dual closed-loop control when taking over control. By publishing the voltage loop output of the new master converter as the total system reference value for the current cycle, each slave converter calculates the reference power based on the total system reference value and the state parameters of its corresponding energy storage unit in the current cycle, thereby achieving power coordination and balanced distribution among the DC-DC converters. Compared with the existing master-slave control method, the new master converter does not need to establish a control loop from scratch, but directly inherits the total system reference value published by the old master converter in the previous cycle as the initial value of the voltage loop integral. This allows the voltage loop to smoothly inherit the existing control information from the original master converter's operating state, and on this basis, executes current / voltage dual closed-loop control to achieve a smooth transition of control quantities, thereby minimizing the sudden changes in voltage and current during master switching. Therefore, the new master converter can maintain stable bus voltage and ensure the continuity of load power distribution during master-slave switching, enabling the overall system to maintain stable operation.

[0052] Figure 5 This is a structural block diagram of a control system for a multi-machine parallel DC-DC converter according to an embodiment of this application. The control system is used to control multiple DC-DC converters connected in parallel in an energy storage system. The control system includes at least the following modules: The master selection module is used to select one DC-DC converter that is in normal working condition as the new master when the system is powered on for the first time or when the existing master fails, and the other DC-DC converters that are in normal working condition are used as slaves. The host inheritance module is used to take the total system reference value published by the old host in the previous cycle as the initial value of the voltage loop integral of the new host, and enable the new host to perform current and voltage dual closed-loop control, and publish the voltage loop output of the new host as the total system reference value of the current cycle. The power allocation module is used to calculate the reference power of each DC converter based on the total system reference value released by the new host in the current cycle and the state parameters of the energy storage units corresponding to each DC converter in the current cycle.

[0053] For relevant details, please refer to the above method implementation examples.

[0054] Figure 6 This is a block diagram of an electronic device provided in one embodiment of the present application, the device including at least a processor 601 and a memory 602.

[0055] Processor 601 may include one or more processing cores, such as a quad-core, octa-core, or other multi-core processor. Processor 601 may be implemented using a DSP (Digital Signal Processor), FPGA (Field-Programmable Gate Array), PLA (Programmable Logic Array), or any combination of the above hardware forms. In some embodiments, processor 601 may include a main processor and a coprocessor, wherein the main processor is used to execute the main control and current / voltage dual closed-loop control algorithms of the parallel DC-DC converter, and the coprocessor is used to handle slave monitoring, communication protocols, or low-power computing tasks. Furthermore, processor 601 may also integrate a GPU (Graphics Processing Unit) for displaying the monitoring interface, or an AI processor for executing energy storage management strategies and power allocation optimization calculations.

[0056] The memory 602 may include one or more computer-readable storage media, which may be non-transitory and used to store program code, system parameters, and historical state information. The memory 602 may also include high-speed random access memory and non-volatile memory, such as a hard disk or flash memory. In some embodiments, the non-transitory storage media in the memory 602 may store at least one instruction set, which is executed by the processor 601 to implement the control method for the multi-machine parallel DC-DC converter provided in this application, including master selection, power allocation, and voltage / current dual closed-loop control.

[0057] In some embodiments, the electronic device may also optionally include a peripheral device interface and at least one peripheral device, with the processor 601, memory 602, and peripheral device interface connected via a bus or signal line. Each peripheral device can be connected to the peripheral device interface via a bus, signal line, or circuit board. Indicatively, peripheral devices include, but are not limited to: a display or touch interface, a communication module, a power monitoring and alarm device, etc.

[0058] Of course, electronic devices may also include fewer or more components, and this embodiment does not limit this.

[0059] Optionally, this application also provides a computer-readable storage medium storing a program that is loaded and executed by a processor to implement the control method of the multi-machine parallel DC-DC converter described in the above method embodiments.

[0060] Optionally, this application also provides a computer product including a computer-readable storage medium storing a program, which is loaded and executed by a processor to implement the control method of the multi-machine parallel DC-DC converter described in the above method embodiments.

[0061] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0062] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A control method for a multi-machine parallel DC-DC converter, characterized in that, The control method for controlling multiple DC-DC converters connected in parallel in an energy storage system includes the following steps: When the system is powered on for the first time or when the existing master fails, one of the DC converters that are in normal working condition is selected as the new master, and the other DC converters that are in normal working condition are selected as slaves. The system total reference value published by the old host in the previous cycle is used as the initial value of the voltage loop integral of the new host, and the new host is made to perform current and voltage dual closed-loop control. The voltage loop output of the new host is published to the outside as the system total reference value of the current cycle. Based on the total system reference value released by the new host in the current cycle and the state parameters of the energy storage units corresponding to each DC converter in the current cycle, the reference power of each DC converter is calculated.

2. The control method according to claim 1, characterized in that, The step of calculating the reference power of each DC-DC converter based on the total system reference value published by the new host in the current period and the state parameters of the energy storage units corresponding to each DC-DC converter in the current period includes the following steps: Obtain the status parameters of the energy storage units corresponding to all DC-DC converters in normal operating condition. The status parameters include the SOC value and the SOP limit value. Based on the state parameters of the energy storage units corresponding to each DC-DC converter, the power allocation ratio of each DC-DC converter is determined. The power allocation ratio of each DC-DC converter is directly proportional to the SOC value of the corresponding energy storage unit when the corresponding energy storage unit is in the discharge state, and inversely proportional to the SOC value of the corresponding energy storage unit when the corresponding energy storage unit is in the charging state. The reference current of each DC converter is calculated based on the total system reference value and the power allocation ratio of each DC converter released by the new host, and the power of the reference current is calculated in combination with the DC bus voltage to obtain the reference power of each DC converter.

3. The control method according to claim 2, characterized in that, Determining the power allocation ratio of each DC-DC converter based on the state parameters of the corresponding energy storage unit of each DC-DC converter includes the following steps: The SOC values ​​of the corresponding energy storage units of all DC-DC converters in normal operating condition are summed to obtain the accumulated SOC value. When the energy storage unit corresponding to each DC-DC converter is in a discharging state, the ratio of the SOC value of the energy storage unit to the accumulated SOC value is used as the power allocation ratio of the DC-DC converter corresponding to that energy storage unit.

4. The control method according to claim 3, characterized in that, The process of determining the power allocation ratio of each DC-DC converter based on the state parameters of the corresponding energy storage unit of each DC-DC converter also includes the following steps: When the energy storage unit corresponding to each DC converter is in the charging state, the energy storage units corresponding to all DC converters in normal working state are sorted from low to high according to the SOC value to obtain the ranking index of each energy storage unit. The ranking index starts counting from zero. Based on the SOC value corresponding to the ranking index of each energy storage unit and the accumulated SOC value, the power allocation ratio of each DC converter is determined according to the following formula. : ； in, For the first Power allocation ratio of each DC-DC converter This represents the number of energy storage units corresponding to a DC-DC converter in normal operating condition. For the first Ranking index of energy storage units corresponding to each DC-DC converter. Indicates the first The SOC value corresponding to each index position. This is the accumulated value of the SOC.

5. The control method according to any one of claims 1-4, characterized in that, Also includes: When the reference power of a DC-DC converter exceeds the SOP limit of its corresponding energy storage unit, the excess reference power is allocated to other DC-DC converters that are in normal working condition for compensation.

6. The control method according to any one of claims 1-4, characterized in that, The step of selecting a new master converter from those in normal working condition when the system is first powered on or when the existing master converter fails includes: When the system is powered on for the first time, the operating status of all parallel DC-DC converters is polled and detected. One of the DC-DC converters that is in normal operating status in two consecutive detection cycles is selected as the new master. When the existing host fails, the operating status of all parallel DC-DC converters is polled and detected, and one of the DC-DC converters that is in normal working condition in one detection cycle is selected as the new host.

7. The control method according to claim 6, characterized in that, In the step of polling and detecting the operating status of all parallel DC-DC converters when the system is first powered on, and selecting one of the DC-DC converters that is in normal operating status in two consecutive detection cycles as the new master, if the same DC-DC converter in normal operating status is selected in two consecutive detection cycles, that DC-DC converter is selected as the new master.

8. A control system for a multi-machine parallel DC-DC converter, characterized in that, The control system is used to control multiple DC-DC converters connected in parallel in an energy storage system, and includes: The master selection module is used to select one DC-DC converter that is in normal working condition as the new master when the system is powered on for the first time or when the existing master fails, and the other DC-DC converters that are in normal working condition are used as slaves. The host inheritance module is used to take the total system reference value published by the old host in the previous cycle as the initial value of the voltage loop integral of the new host, and enable the new host to perform current and voltage dual closed-loop control, and publish the voltage loop output of the new host as the total system reference value of the current cycle. The power allocation module is used to calculate the reference power of each DC converter based on the total system reference value released by the new host in the current cycle and the state parameters of the energy storage units corresponding to each DC converter in the current cycle.

9. An electronic device, characterized in that, It includes a processor and a memory, wherein the memory stores a program that is loaded and executed by the processor to implement the control method for a multi-machine parallel DC-DC converter as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a program that, when executed by a processor, is used to implement the control method for a multi-machine parallel DC-DC converter as described in any one of claims 1-7.

Images