Parallel operation control device of power supply module, power supply module and energy storage parallel operation system

Abstract

The invention relates to the technical field of power supplies, and discloses a parallel operation control device of a power supply module, the power supply module and an energy storage parallel operation system. The device comprises a sampling module, a communication module and a controller, and the controller is used for dynamically switching different loop control strategies so as to control the output of a power supply module in an energy storage parallel operation system; wherein the loop comprises a voltage loop, a first current loop and a second current loop, the voltage loop is used for adjusting the output voltage, and the first current loop is used for adjusting the charge state or the output current in combination with communication feedback data obtained by the communication module, so that the charge state or the output current is balanced with the charge state or the output current of other power modules in the energy storage parallel operation system; the second current loop is used for adjusting the output current. According to the invention, through independent loop control, different loops are dynamically switched according to load change to adjust self output, so as to ensure that the power supply module in a parallel operation state keeps load balance under different working conditions.

Description

Technical Field

[0001] The present application relates to the field of power supply technology, and in particular to a parallel control device for a power module, a power module, and an energy storage parallel system. Background Art

[0002] The bidirectional power parallel system plays an important role in modern power systems, especially in application scenarios that require high reliability, high efficiency, and flexible power dispatch. In common power system designs, a single power supply device may not be able to meet the needs of high-power loads, or a backup power supply is required to ensure power supply continuity when a single power supply fails. The bidirectional power parallel system connects multiple power supply devices in parallel to supply power to the load together, which not only increases the total output power of the system, but also enhances the stability and redundancy of the system.

[0003] However, when multiple power modules are working in parallel, it is often difficult to ensure that they can evenly distribute the load current (current sharing) and maintain the same state (State of Charge) in the battery system. That is, load imbalance is likely to occur between the power modules in the parallel system, which will lead to low operating efficiency and poor reliability of the entire parallel system. Summary of the invention

[0004] In view of this, in order to solve the technical problem of uneven loads on each power module in a parallel system in the prior art, the present application provides a parallel control device for a power module, a power module and an energy storage parallel system.

[0005] In a first aspect, the present application provides a parallel control device for a power module, comprising:

[0006] A sampling module, used for collecting the state data of the power module in real time;

[0007] Communication module, used to connect other power modules in the energy storage parallel system to obtain communication feedback data;

[0008] A controller, used for dynamically switching different loop control strategies according to the self-state data to control the output of the power module in the energy storage parallel system;

[0009] The loop includes a voltage loop, a first current loop and a second current loop. The voltage loop is used to adjust the output voltage of the power module. The first current loop is used to adjust the charge state or output current of the power module in combination with the communication feedback data to achieve balance with the charge state or output current of other power modules in the energy storage parallel system; the second current loop is used to adjust the output current of the power module within a preset current range.

[0010] In an optional embodiment, the controller is used to call a voltage loop control strategy according to an actual output voltage of the power module after the power modules are connected in parallel, so as to control the output voltage of the power module within a preset voltage fluctuation range through the voltage loop.

[0011] In an optional embodiment, the controller is used to call the first current loop control strategy according to the set working mode of the power module when the output voltage of the power module is within the voltage fluctuation range, so as to control the balanced output of the power module through the first current loop;

[0012] The types of working modes include current sharing mode and charge sharing state mode.

[0013] In an optional implementation manner, the communication feedback data includes a parallel maximum SOC value, and the self-state data includes a local SOC value;

[0014] The controller is also used to determine whether to execute the operation of calling the first current loop control strategy according to the set working mode of the power module according to the difference between the maximum SOC value of the parallel machine and the local SOC value;

[0015] If the difference is within the allowable deviation range, it is determined to maintain the operation of calling the voltage loop control strategy;

[0016] If the difference is not within the allowable deviation range, it is determined to execute the operation of calling the first current loop control strategy according to the set working mode of the power module.

[0017] In an optional embodiment, the communication feedback data includes an average load current;

[0018] The controller is used to adjust the output current according to the load average current when entering the current sharing mode.

[0019] In an optional implementation manner, the communication feedback data includes the average load current, the average load SOC value and the number of parallel machines;

[0020] The controller is used for calculating a first current reference value when entering the equalized charge state mode, if it is determined that the first current value is less than a preset overload current, so as to adjust the output current according to the first current reference value;

[0021] If it is determined that the first current value is not less than the preset overload current, calculating a second current reference value to adjust the state of charge according to the second current reference value;

[0022] Wherein, the calculation expression of the first current value is:

[0023] The first current value = maximum parallel SOC value / (number of parallel machines * average load SOC value) * number of parallel machines * average load current;

[0024] The calculation expression of the first current reference value is:

[0025] The first current reference value = local SOC value / (number of parallel machines * average SOC value of load) * number of parallel machines * average current of load;

[0026] The calculation expression of the second current reference value is:

[0027] The second current reference value=local SOC value / (number of parallel machines*average SOC value of load)*number of parallel machines*average load current+number of parallel machines*preset parameter value.

[0028] In an optional embodiment, it also includes:

[0029] A step trigger is used to monitor the step current change event of the load;

[0030] The controller is also used to call a second current loop control strategy when the step current change event is triggered, so as to control the output current of the power module within the preset current range through the second current loop; or, call a voltage loop control strategy to control the output voltage of the power module within the preset voltage range through the voltage loop.

[0031] In an optional embodiment, the step trigger is specifically used to determine that the step current change event is triggered if it is determined that the integral value of the change in the local current value in the own state data within the target time period is within the allowable change range or exceeds the allowable change range.

[0032] In an optional implementation, the controller is further configured to: if it is determined that the integral value exceeds the allowable variation range, call the voltage loop control strategy to control the output voltage of the power module within the preset voltage range through the voltage loop;

[0033] If it is determined that the integral value is within the allowable variation range, the second current loop control strategy is called to ensure that the output current of the power module is within the preset current range.

[0034] In an optional embodiment, after performing corresponding control according to the step current change event, the controller is further used to determine the working mode of the power module and call the first current loop control strategy to control the balanced output of the power module through the first current loop.

[0035] In an optional embodiment, it also includes:

[0036] The data processing module is used to pre-process the current data and the self-state data in the communication feedback data respectively, and the pre-processed current data and self-state data are used to be input into the controller for processing.

[0037] In an optional implementation manner, the data processing module is specifically used to filter the self-state data;

[0038] The data processing module is specifically used to filter the current data in the communication feedback data, and then use a ramp function to converge the filtered current data to obtain updated current data for input into the first current loop.

[0039] In a second aspect, the present application provides a power supply module, comprising the parallel control device as described above.

[0040] In a third aspect, the present application provides an energy storage parallel system, comprising a plurality of power modules as described above, each of the power modules being connected in parallel, and each of the power modules being used to implement a parallel control function through its own parallel control device when in a parallel state.

[0041] In an optional embodiment, the parallel system is used to determine one of the power modules as a communication master and the other power modules as communication slaves according to a bus communication protocol used between the power modules;

[0042] The communication host is used to obtain the slave status data of each of the communication slaves, process according to its own status data and the slave status data, obtain communication feedback data, and send the communication feedback data to each of the communication slaves;

[0043] Each of the power modules is also used to determine whether it is a parallel control master or a parallel control slave according to the communication feedback data; wherein, when serving as the parallel control slave, the parallel control function is realized through its own parallel control device.

[0044] The embodiments of the present application have the following beneficial effects:

[0045] The embodiment of the present application provides a parallel control device, which includes a sampling module, a communication module and a controller. The sampling module is used to collect the self-state data of the power module in real time; the communication module is used to connect other power modules in the energy storage parallel system to obtain communication feedback data; the controller is used to dynamically switch different loop control strategies according to its own state data to control the output of the power module in the energy storage parallel system; wherein the loop includes a voltage loop, a first current loop and a second current loop, the voltage loop is used to adjust the output voltage of the power module, the first current loop is used to adjust the charge state or output current of the power module in combination with the communication feedback data to achieve balance with the charge state or output current of other power modules in the energy storage parallel system; the second current loop is used to adjust the output current of the power module within a preset current range. The embodiment of the present application uses independent loop control to dynamically switch different loops according to load changes to adaptively adjust its own output, and ultimately only one of the three loops has a valid output to ensure that the power module in the parallel state maintains load balance under different working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present application and should not be regarded as limiting the scope of protection of the present application. For ordinary technicians in this field, other related drawings can also be obtained based on these drawings without creative work.

[0047] Figure 1 A schematic diagram of the structure of the energy storage parallel system in the embodiment of the present application is shown;

[0048] Figure 2 A schematic diagram of the structure of a parallel control device in an embodiment of the present application is shown;

[0049] Figure 3 A schematic diagram of a loop control principle of the parallel control device in the parallel control process in an embodiment of the present application is shown;

[0050] Figure 4 A schematic diagram of a flow chart of a parallel control process of a parallel control device in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0052] The components of the embodiments of the present application generally described and shown in the drawings herein may be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0053] Hereinafter, the terms "including", "having" and their cognates, which may be used in various embodiments of the present application, are intended only to indicate specific features, numbers, steps, operations, elements, components, or combinations of the foregoing items, and should not be understood as first excluding the existence of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing items or adding the possibility of one or more features, numbers, steps, operations, elements, components, or combinations of the foregoing items.

[0054] Furthermore, the terms “first”, “second”, “third”, etc. are merely used for distinguishing descriptions and are not to be understood as indicating or implying relative importance.

[0055] Unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meanings as those generally understood by those skilled in the art to which the various embodiments of the present application belong. The terms (such as those defined in generally used dictionaries) will be interpreted as having the same meanings as the contextual meanings in the relevant technical field and will not be interpreted as having idealized meanings or overly formal meanings unless clearly defined in the various embodiments of the present application.

[0056] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0057] Bidirectional power refers to a power system that can achieve bidirectional energy flow, which can output energy to the outside world and absorb energy from the outside world. Typical bidirectional power applications include energy exchange between energy storage systems (such as batteries) and power grids, and energy feedback from electric vehicles (Vehicle-to-Grid, V2G).

[0058] Parallel operation refers to the operation of multiple power modules in parallel, which enables the system to increase capacity or redundancy and improve reliability. During parallel operation, it is necessary to ensure that all power modules can evenly bear the load to avoid overloading some modules and leaving some modules idle.

[0059] PID (Proportion-Integral-Differential), which means proportional-integral-differential, is a commonly used closed-loop controller.

[0060] The bidirectional power parallel system can realize the bidirectional flow of energy, that is, it can supply power to the load and absorb energy from the load, which is of great significance in some special application scenarios, such as energy storage systems and electric vehicle charging stations. This bidirectional management of energy requires the system to have efficient energy conversion and management capabilities, and also needs to ensure the load balance between the various power modules in the parallel system, so as to ensure the safety and stability of the parallel system under different working conditions.

[0061] Based on this, see Figure 1 The embodiment of the present application provides an energy storage parallel system 1000 (hereinafter referred to as the parallel system 1000), which includes a plurality of power modules 100 (such as power module 1, power module 2, ..., power module n shown in the figure, where n is an integer not equal to 0), and each power module 100 is connected in parallel; wherein, the power module 100 described in this embodiment includes but is not limited to devices or modules such as battery packs, inverters, DC-DC converters, etc., and this embodiment is not limited to this.

[0062] It can be understood that the parallel system 1000 can be connected to multiple power modules 100, and each power module 100 can work in parallel at the same time to improve the operating efficiency of the system.

[0063] In some examples, the power modules 100 in the parallel system 1000 may communicate with each other using a bus communication protocol such as CAN, and this embodiment does not limit the bus communication protocol.

[0064] Furthermore, the parallel system 1000 can determine one of the power modules 100 as the communication host through the bus communication protocol, and the other power modules 100 of the parallel system 1000 are the communication slaves; the communication host is used to obtain the status data of each communication slave, and process the status data of each communication slave and its own status data to obtain communication feedback data, and send the communication feedback data to each communication slave. Each power module 100 can autonomously adjust the local output based on the communication feedback data to ensure the load balance between the power modules 100 in the parallel system 1000 and realize parallel control. Among them, the status data includes but is not limited to current data and charge state data.

[0065] Exemplarily, if each power module 100 communicates with each other through the CAN communication protocol, the parallel system 1000 determines a CAN communication host according to the CAN communication protocol between each power module 100, and the communication host obtains the current data and charge state data of each communication slave and itself, and calculates the communication feedback data including the average load current (denoted as Ave_Current), the number of online devices in parallel (denoted as Online_Packs), the maximum SOC value of parallel (denoted as Max_Soc), the minimum SOC value of parallel (denoted as Min_Soc) and the average load SOC value (denoted as Ave_Soc) through the current data and charge state data of all power modules 100. Then, the communication host sends the communication feedback data to each communication slave, so that each power module 100 performs parallel control according to the communication feedback data.

[0066] Furthermore, each power module 100 can determine whether it is a parallel control master or a parallel control slave through the communication feedback data. If it is determined that it is not a parallel control master, that is, when the power module 100 acts as a parallel control slave, it adjusts its own charge state or output current to realize the parallel control function, thereby achieving load balancing within the parallel system 1000.

[0067] Optionally, in this embodiment, the specific positions of the communication host and the parallel control host can also be determined by the CAN bus numbers corresponding to the power modules 100. Furthermore, the working processes of the communication host and the parallel control host do not interfere with each other.

[0068] In this embodiment, a parallel control device 110 may be provided in each power module 100 , and each power module 100 is used to implement a parallel control function through the parallel control device 110 when the power module 100 is in a parallel state.

[0069] For reference, Figure 2 As shown, the parallel control device 110 includes a sampling module 111 , a communication module 112 and a controller 113 , and the sampling module 111 , the communication module 112 and the controller 113 communicate with each other.

[0070] Further, the sampling module 111 is used to collect the self-state data of the power module 100 in real time; wherein the self-state data includes but is not limited to the local current value (recorded as L_Current) and the local SOC value (recorded as L_Soc), etc. In addition, the sampling module 111 can adopt a sampling method such as dual-channel interleaved sampling and / or 8 times oversampling when acquiring the self-state data to improve the accuracy and reliability of the data, etc., but this embodiment does not limit the sampling method adopted.

[0071] In this embodiment, the communication module 112 is used to connect to other power modules 100 in the parallel system 1000 to obtain communication feedback data of other power modules 100; wherein, the communication feedback data includes but is not limited to the average load current, the number of parallel online devices, the maximum parallel SOC value, the minimum parallel SOC value and the average load SOC value, etc., which are not limited in this embodiment.

[0072] In addition, the communication module 112 is also used to transmit the state data collected by the sampling module 111 to other power modules 100. That is, each power module 100 in parallel operation realizes data exchange through its own communication module 112.

[0073] In some examples, the parallel control device 110 further includes a data processing module, which is used to pre-process the communication feedback data and the self-state data respectively, and the pre-processed communication feedback data and the self-state data are used to be input into the controller 113 for processing.

[0074] Furthermore, the preprocessing operation of the data processing module on its own state data is filtering the own state data to remove noise or interference data in the own state data.

[0075] Taking the current data in the communication feedback data as an example, the data processing module preprocesses the communication feedback data, that is, filters the current data and converges the filtered current data using a ramp function to obtain updated current data for input into the first current loop.

[0076] In this embodiment, one or more filtering algorithms may be used in the above two filtering processes, and the type of the adopted filtering algorithm is not limited.

[0077] Exemplarily, the process of converging the current data in this embodiment may be that if the corresponding current value in the current data is greater than the average current of the load, the ramp function is used to converge slowly; wherein, this embodiment may define the slope of the ramp function according to actual needs, and generate a corresponding ramp function, so as to control the current data by using the slope of the ramp function as the control amplitude; wherein, the higher the degree to which the target current value is greater than the average current of the load, the greater the corresponding slope; it can be understood that the greater the difference between the target current value and the average current of the load, the greater the control amplitude when the target current value is converged by the ramp function. For example, if (target current - average current of the load)>50mA, the ramp function is used to converge quickly, so that the target current is controlled to 50mA; if (target current - average current of the load)>100mA, the ramp function is used to converge quickly, so that the target current is controlled to 100mA.

[0078] In this embodiment, the communication feedback data can be converged by a ramp function to slow down the rate of change of each communication feedback data, so as to avoid the situation where the output of the parallel system 1000 fluctuates greatly (overshoot and undershoot) when approaching the target value; that is, the ramp function gradually changes the value of the parameter to make it smoothly transition to the target value, thereby avoiding the negative impact caused by sudden changes. For example, when the current data is gradually converged by the ramp function, the current can be made to reach the target value smoothly, avoiding large fluctuations in the current in a short time, thereby reducing the transient response of the system during the adjustment process and improving the stability and robustness of the system. In summary, this embodiment uses the ramp function to achieve a smooth transition of each communication feedback data, suppress overshoot and undershoot, so as to improve the stability of the system and adapt to dynamic load changes, so as to make the system output more stable and controllable.

[0079] In one embodiment, when processing the communication feedback data and its own status data respectively, each power module 100 gives priority to processing its own status data, thereby avoiding overload of a single power module 100 and improving the balancing performance and reliability of the parallel system 1000.

[0080] Furthermore, the controller 113 is used to dynamically switch different loop control strategies according to the state data thereof, so as to control the output of the power module 100 itself in the parallel system 1000 .

[0081] Among them, the internal loop of each power module 100 includes a voltage loop, a first current loop and a second current loop; the voltage loop is used to adjust the output voltage of the power module 100; the first current loop is used to adjust the charge state or output current of the power module 100 in combination with the communication feedback data to achieve balance with the charge state or output current of other power modules 100 in the parallel system 1000; the second current loop is used to adjust the output current of the power module 100 within a preset current range.

[0082] It can be understood that each power module 100 in the parallel system 1000 can autonomously adjust its output according to its own state data and communication feedback data through the internal loop structure, that is, each power module 100 can adaptively control the local balanced output, so that the output of each power module 100 in the parallel system 1000 remains consistent, and the load balance and state balance between the power modules 100 in the parallel system 1000 are achieved, and the stability of the operation of the parallel system 1000 is ensured. In addition, when the load changes, each power module can be locally controlled through an independent internal loop to autonomously achieve balanced adjustment without waiting for the instructions of the parallel system 1000 or other global controllers, so that decentralized autonomous control can be achieved, avoiding the impact caused by the reduced response speed to system load changes due to communication delays, and significantly improving the reliability of the parallel system.

[0083] The following example illustrates the process of dynamically switching different loop control strategies to regulate output after the power modules 100 are connected in parallel.

[0084] In one embodiment, after the power modules 100 are connected in parallel, the controller 113 of each power module 100 is used to call the voltage loop control strategy according to the actual output voltage of the power module 100, so as to control the output voltage of the power module 100 within a preset voltage fluctuation range through the voltage loop.

[0085] The voltage loop control strategy corresponding to the voltage loop is to determine a voltage reference value (denoted as Vref) according to the local voltage value (i.e., the current actual output voltage) in the communication feedback data and the self-state data, and input the voltage reference value Vref into the voltage loop to adjust the output voltage of the power module 100 through the voltage reference value Vref. Under the control of the voltage loop, the output voltage at the next moment is infinitely close to the voltage reference value; and this embodiment does not limit the determination process of the voltage reference value.

[0086] That is, the output voltage value at the next moment output by the power supply module 100 controlled by the voltage loop can be within the voltage fluctuation range corresponding to the voltage reference value. The upper and lower limits of the fluctuation range can be set according to actual needs, and this embodiment does not limit this.

[0087] In one example, if Figure 3 As shown, the voltage loop can use a PID closed-loop controller to implement the voltage loop control strategy. That is, the PID closed-loop controller calculates the difference between the input parameter value (the actual output voltage (i.e., Vout) and the voltage reference value (i.e., Vref)), and then determines the adjustment amount according to the difference, and then determines the output voltage size at the next moment according to the adjustment amount, so that the power module 100 outputs an output voltage of corresponding size.

[0088] In this embodiment, the voltage loop and its voltage loop control strategy are used to ensure the stability of the overall voltage output of the parallel system 1000, especially when the load fluctuates or the environment changes, so that the output voltage inside each power module 100 is stabilized within a predetermined range, thereby achieving the voltage stability of the parallel system 1000 under different load conditions, reducing voltage fluctuations, and thus improving the overall operation stability of the system; avoiding fluctuations in the system due to large load changes caused by voltage instability.

[0089] It is worth noting that after each power module 100 is powered on in parallel, it preferentially uses the internal voltage loop and the voltage loop control strategy corresponding to the voltage loop to ensure stable voltage output (i.e., ensures that the output voltage of the power module 100 is within a preset voltage fluctuation range), and after ensuring stable voltage output, it enters the corresponding balancing mode (such as current equalization mode or charge equalization state mode) to control its own balanced output through the first current loop.

[0090] Furthermore, the controller 113 of each power module 100 is also used to call the first current loop control strategy according to the set working mode of the power module 100 when the output voltage of the power module 100 is within a preset voltage fluctuation range, so as to control the balanced output of the power module 100 through the first current loop.

[0091] In some examples, before controlling the balanced output of the power module 100 through the first current loop, the controller 113 is also used to determine whether to execute the operation of calling the first current loop control strategy according to the set working mode of the power module 100 based on the difference between the maximum parallel SOC value and the local SOC value; wherein, if the difference between the maximum parallel SOC value and the local SOC value is within the allowable deviation range, it is determined to maintain the operation of calling the voltage loop control strategy; if the difference between the maximum parallel SOC value and the local SOC value is not within the allowable deviation range, it is determined to execute the operation of calling the first current loop control strategy according to the set working mode of the power module 100.

[0092] The upper and lower limits of the allowable deviation range can be set according to actual needs, and this embodiment does not limit this. For example, the allowable deviation range can be 1%. For example, if (Max_Soc-L_Soc)<=1%, the operation of calling the voltage loop control strategy is maintained to control the output of the power module 100 itself through the voltage loop; if (Max_Soc-L_Soc)>1%, the output of the power module 100 itself is controlled through the first current loop.

[0093] It can be understood that if the deviation between the maximum parallel SOC value and the local SOC value is too large, the local SOC is adjusted through the first current loop and its corresponding first current loop control strategy to ensure the balance of the charge state between each power module 100; if the deviation between the maximum parallel SOC value and the local SOC value is small, it means that the local charge state has reached the maximum, and there is no need to adjust it through the first current loop, but to stabilize its own voltage output through the voltage loop and its voltage loop control strategy.

[0094] It should be noted that the first current loop control strategies are different in different working modes, wherein the types of the working modes include a current sharing mode and a charge sharing state mode.

[0095] It is worth noting that in the current sharing mode, the controller adjusts the output current through the first current loop so that the current output of each power module remains balanced; in the charge state sharing mode, the controller adjusts the output current through the first current loop, and then adjusts its own charge state by adjusting the output current, so that the charge state of each power module remains balanced.

[0096] Further, in some examples, the controller 113 is used for, when entering the current sharing mode, the first current loop control strategy is to adjust its own output current by using the load average current as a third current reference value (recorded as Iref1), that is, by using the third current reference value Iref1 to perform closed-loop feedback adjustment on its own actual local current value (recorded as Iout1) using the first current loop, so as to use the load average current as the desired output current. It can be understood that under the regulation of the first current loop, the output current at the next moment approaches the third current reference value Iref1.

[0097] In some examples, when entering the evenly charged state mode, the process of the controller 113 executing the first current loop control strategy may be: first calculate the first current value (denoted as I1) based on the communication feedback data and its own state data; wherein, the calculation process of the first current value is: calculate the first product value of the number of parallel machines and the average SOC value of the load, then calculate the first quotient value of the maximum parallel SOC and the first product value, and then calculate the first quotient value and the second product value between the number of parallel machines and the average load current.

[0098] The calculation expression of the first current value is:

[0099] I1=Max_Soc / (Online_Packs*Ave_Soc)*Online_Packs*Ave_Current.

[0100] Further, if it is determined that the first current value is less than the preset overload current, the second quotient of the local SOC value and the second product value is calculated, and then the third product value between the second quotient and the number of parallel machines and the average load current is calculated, and then the magnitude of the output current is adjusted by the third product value, that is, the calculated third product value is used as the first current reference value (recorded as Iref2) and the actual local current value collected by itself (recorded as Iout1) and input into the first current loop to calculate the output current at the next moment, so as to achieve the purpose of adjusting the state of charge by adjusting the local output current. Among them, the magnitude of the output current at the next moment is close to the first current reference value Iref2.

[0101] For example, the calculation expression of the first current reference value Iref2 in this case is as follows:

[0102] Iref2=L_Soc / (Online_Packs*Ave_Soc)*Online_Packs*Ave_Current.

[0103] On the contrary, if it is determined that the first current value is not less than the preset overload current, the fourth product value between the number of parallel machines and the preset parameter is calculated, and then the sum value between the fourth product value and the third product value is calculated, so as to adjust the local output current by the size of the sum value, wherein the sum value can be used as the second current reference value Iref3 input into the first current loop, and the first current loop calculates the output current at the next moment by the second current reference value Iref3. Among them, the preset parameter value can be set according to actual needs, for example, it can be set to 1A, etc.

[0104] For example, the calculation expression of the second current reference value Iref3 in the above case is as follows:

[0105] Iref3=L_Soc / (Online_Packs*Ave_Soc)*Online_Packs*Ave_Current+Online_Packs*1A.

[0106] It should be noted that an external controller such as a host computer or a cloud platform or the parallel system 1000 can also send a mode instruction to each power module 100. The mode instruction is used to instruct each power module 100 to execute the corresponding working mode (current sharing mode or charge sharing mode). That is, after receiving the mode instruction, each power module 100 executes the working mode indicated in the mode instruction.

[0107] In addition, the parallel system 1000 can select either the current equalization module or the equalized charge state mode as the default operating mode, that is, when the output voltage of the power module 100 is within the preset voltage fluctuation range, each power module 100 can automatically call the first current loop control strategy directly according to the default operating mode without receiving additional mode instructions, so as to control the balanced output of the power module 100 through the first current loop.

[0108] In one example, if Figure 3 As shown, the first current loop can use a PID closed-loop controller to implement the first current loop control strategy. That is, the PID closed-loop controller determines the adjustment amount of the output current according to the input parameter value (the current reference value (Iref1, Iref2, Iref3) obtained according to the communication feedback data and the local current value (i.e., Iout1) in its own state data), and then adjusts the magnitude of the output current according to the adjustment amount, so that the power module 100 outputs an output current of corresponding magnitude, thereby realizing the regulation of the current sharing or charge sharing state in the corresponding working mode.

[0109] In this embodiment, the parallel system 1000 ensures current output balance or SOC balance between the power modules 100 by adjusting the current distribution of each power module 100 and monitoring and adjusting the output current of each module in real time; wherein, the current output control of each power module 100 is achieved through the first current loop inside each power module 100 and its first current loop control strategy, that is, each power module 100 achieves current balanced output through the internal first current loop to ensure load balance of the parallel system 1000, prevent overload or underload problems caused by uneven current between the power modules 100, and ensure uniform distribution of current load when the power modules 100 are operated in parallel, thereby achieving current balance or SOC balance between the power modules 100.

[0110] It is worth noting that after each power module 100 is powered on in parallel and ensures stable voltage output, if its own output voltage or local SOC value is determined to be the maximum value among each power module 100 based on the received communication feedback data, it can be determined that it is the parallel control master; otherwise, it is determined that it is the parallel control slave.

[0111] For reference, each power module 100 can exchange data with other power modules 100 through the internal communication module 112, so that its own local output voltage or local SOC value can be compared with other power modules 100 to determine whether it is the maximum value, and thus determine whether it is the parallel control host.

[0112] Optionally, each power module 100 can update its own identity (i.e., whether it is a parallel control host or a parallel control slave) according to real-time changing communication feedback data, that is, the location of the parallel control host can be dynamically updated according to the real-time output of each power module 100.

[0113] Moreover, during the regulation process of each power module 100 in the current sharing mode or the equalized charge state module, only the parallel control slave calls the first current loop control strategy to control the balanced output of the power module 100 through the first current loop; and the parallel control host does not need to call the first current loop control strategy, and in this process, the parallel control host continues to call the voltage loop control strategy to control the local stable output voltage through the voltage loop; wherein the stable voltage value output by the parallel control host is provided to each parallel control slave to regulate its own balanced output.

[0114] It can be understood that during the current sharing control or charge sharing state control process of the parallel system 1000, the parallel control host only calls the voltage loop control strategy to provide a stable voltage value to each parallel control slave through the voltage loop, so that each parallel control slave calls the first current loop control strategy, controls its own current output through the first current loop, and then controls its own current output to regulate its own local voltage value to slowly approach the stable voltage value or be within a suitable fluctuation range including the stable voltage value.

[0115] In some examples, the parallel control device 110 further includes a step trigger, where the step trigger is used to monitor a step current change event of the load.

[0116] Furthermore, during the process of monitoring the step current change event, if the step trigger determines that the integral value of the change amount of the local current value in the state data within the target time period is within the allowable change range or exceeds the allowable change range, then the step current change event is determined to be triggered. On the contrary, if the step trigger determines that the integral value is not within the allowable change range and does not exceed the allowable change range, then the step current change event is determined not to be triggered.

[0117] It can be understood that this embodiment uses the step trigger to monitor the change of the local current value output by itself, and calculates the integral value of the change amount of the local current value within the target time period, so as to determine whether to trigger the step current change event according to the integral value. Among them, the values ​​of the target time period and the allowable change range can be set according to actual needs, and this embodiment does not limit this.

[0118] The controller 113 is also used to call the second current loop control strategy when the step current change event is triggered, so as to control the output current of the power module 100 within a preset current range through the second current loop; or, to call the voltage loop control strategy so as to control the output voltage of the power module 100 within a preset voltage range through the voltage loop.

[0119] Furthermore, if it is determined that the step current change event is triggered and the integral value of the change in the local current value within the target time period is within the allowable change range, the controller 113 calls the second current loop control strategy to control the output current of the power module 100 within a preset current range through the second current loop.

[0120] For reference, the output current regulation process of the second current loop is that the controller 113 first determines a fourth current reference value according to the maximum current value of the current load (recorded as Iref4) and the current data in the communication feedback data, and inputs the fourth current reference value into the second current loop. The second current loop adjusts the local current value (recorded as Iout2) according to the fourth current reference value, so that the local output current at the next moment is within a preset current range. Among them, the upper and lower limits of the preset current range can be set according to actual needs and are not limited here.

[0121] In one embodiment, if Figure 3 As shown, the second current loop can use a PID closed-loop controller to execute the corresponding second current loop control strategy according to the corresponding working mode. That is, the PID closed-loop controller determines the adjustment amount of the output current in the corresponding working mode according to the input parameter value (the fourth current reference value Iref4 and the local current value Iout2 in its own state data), and then adjusts the magnitude of the output current according to the adjustment amount, so that the power module 100 outputs an output current of a corresponding magnitude, thereby ensuring that the output current of each power module 100 remains consistent, avoiding the situation in which some power modules 100 in the system are overloaded, some power modules 100 are idle, or some power modules 100 are overcharged or over-discharged.

[0122] It can be understood that this embodiment realizes step control through the second current loop and its second current loop control strategy, so that each power module 100 can quickly adjust the local current output size when the load changes suddenly, quickly respond to the load change, and ensure that the parallel system 1000 can still maintain a stable current output during transient changes. Obviously, this embodiment significantly improves the dynamic load response speed through the step trigger, ensures that the current can be quickly stabilized when the load changes in steps, thereby reducing current overshoot and undershoot, and overcomes the problems of slow response and poor transient performance in the balanced control process in the prior art, so that the parallel system 1000 can quickly adjust the current output when facing a sudden load change, ensuring the stability of operation.

[0123] In addition, in actual scenarios, the sudden change speed of the load current is much faster than the transmission of communication. Therefore, when this embodiment uses the step trigger to implement step detection, it can avoid the control lag caused by communication delay, thereby reducing the probability of insufficient dynamic response and communication delay problems in the parallel system 1000.

[0124] Further, if it is determined that the step current change event is triggered and the integral value of the change amount of the local current value within the target time period exceeds the allowable change range, the controller 113 calls the voltage loop control strategy to control the output voltage of the power module 100 within the preset voltage range through the voltage loop. Among them, the upper and lower limits of the preset voltage range can be set according to actual needs and are not limited here.

[0125] It can be understood that when the voltage is regulated by the voltage loop, the output voltage itself can be adjusted to the ideal state more quickly, that is, the output itself can be quickly regulated by the voltage loop, thereby indirectly and quickly adjusting the size of the local output current.

[0126] Therefore, when the integral value of the change is greater than the allowable change range (that is, it means that the load mutation is too large), the controller 113 can call the voltage loop control strategy to quickly adjust its own voltage output through the voltage loop, so that the power module 100 can quickly achieve a stable voltage output, and then indirectly quickly stabilize its own current output to ensure the stability of the parallel system 1000.

[0127] For example, if the local current rise value is greater than a predetermined current change value (such as 10A) per unit time (such as within 4 cycles), or the communication bus current rise value within a communication cycle reaches a preset threshold value (this embodiment does not limit the value of the preset threshold value; for example, the preset threshold value = 10*total number of power modules 100), then each power module 100 can switch the loop to local voltage loop control through the parallel control device 110, thereby making the parallel system 1000 as a whole under voltage loop control, thereby achieving passive voltage current sharing. At this time, the parallel system 1000 can bear the maximum load of (power of a single power module 100*total number of power modules 100).

[0128] It should be noted that after achieving step control through the second current loop and its second current loop control strategy, or when it is determined that the integral value of the change exceeds the allowable change range, the voltage loop control strategy is used to control and output a stable voltage value, the controller 113 can also call the first current loop control strategy again to regulate its own balanced output through the first current loop.

[0129] That is, after the controller 113 completes the step control, it can determine the working mode (current sharing mode or charge sharing state mode) of the power module 100 again, and call the first current loop control strategy corresponding to the working mode to control the balanced output of the power module 100 through the first current loop. Among them, the process of determining the working mode in this step can be to follow the working mode to be entered set by the power module 100 itself, or to adaptively select the working mode to be entered, or to determine the working mode according to the received mode instruction; the determination process is not limited here.

[0130] It can be understood that after this embodiment realizes output regulation under abnormal conditions through the second current loop, the voltage loop and its corresponding control strategy, it can continue to realize local balanced output through the first current loop, so that each power supply module 100 itself is always in a balanced state to ensure the stability of the parallel system 1000 during operation.

[0131] In summary, if Figure 4 As shown, the process of realizing parallel control of a single power module 100 can be briefly understood as follows: after the parallel machine is powered on, the corresponding data is obtained through the sampling module 111 and the communication module 112, and the controller 113 then controls itself to output a stable voltage through the voltage loop according to the data, and then enters the current sharing mode or the charge sharing state mode to control its own balanced output through the first current loop; in this process, the step current change event of the load can also be monitored through a step trigger. After the step current change event is triggered, the controller 113 controls its own current output through the second current loop, and after determining that its own current output is stable under the control of the second current loop, it can continue to control its own balanced output through the first current loop. That is, each power module 100 controls the output through one of the three loops, and dynamically adjusts the loop control status according to the feedback of the actual situation to ensure the stability of the output of the power module 100 itself, and at the same time ensure that the load of each power module 100 in the parallel system 1000 is evenly distributed, so that the parallel system 1000 can still maintain stable current and voltage output when dealing with complex load changes, thereby improving the reliability of the parallel system 1000.

[0132] In this embodiment, through the independent loop control inside each power module 100 in the parallel system 1000, according to the load change, the output is adaptively adjusted to ensure the load balance between each power module 100, so that the parallel system 1000 can adapt to different working environments. In addition, only one loop output is effective among the three loops to ensure that the system maintains stable operation and current balance between the power modules 100 under different working conditions, and ensures that the SOC of the power modules 100 is consistent; it can be seen that the internal loop control logic of each power module 100 is essentially a first-order processing logic, so that the power module 100 has higher stability and response speed. Through the dynamic switching control of the local loop between each power module 100, a fast dynamic response to load changes and a fast adjustment of stable voltage output, balanced current distribution and consistent SOC management are achieved, and the overall performance of the parallel system 1000 is optimized. Compared with the dual-loop control commonly used in the prior art, this embodiment comprehensively improves the dynamic response, stability and balanced management of the parallel system 1000 through the three-loop control mechanism.

[0133] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and structure diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in an alternative implementation, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the structure diagram and / or the flow diagram, and the combination of boxes in the structure diagram and / or the flow diagram, can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0134] In addition, the functional modules or units in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0135] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a smart phone, a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the various embodiments of the present application.

[0136] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A parallel control device for a power module, characterized in that: include: A sampling module, used for collecting the state data of the power module in real time; Communication module, used to connect other power modules in the energy storage parallel system to obtain communication feedback data; A controller, used for dynamically switching different loop control strategies according to the self-state data to control the output of the power module in the energy storage parallel system; The loop includes a voltage loop, a first current loop and a second current loop. The voltage loop is used to adjust the output voltage of the power module. The first current loop is used to adjust the charge state or output current of the power module in combination with the communication feedback data to achieve balance with the charge state or output current of other power modules in the energy storage parallel system; the second current loop is used to adjust the output current of the power module within a preset current range.

2. The parallel control device according to claim 1, characterized in that: The controller is used to call a voltage loop control strategy according to the actual output voltage of the power module after the power modules are connected in parallel, so as to control the output voltage of the power module within a preset voltage fluctuation range through the voltage loop.

3. The parallel control device according to claim 1 or 2, characterized in that: The controller is used for, when the output voltage of the power module is within the voltage fluctuation range, calling the first current loop control strategy according to the set working mode of the power module, so as to control the balanced output of the power module through the first current loop; The types of working modes include current sharing mode and charge sharing state mode.

4. The parallel control device according to claim 3, characterized in that: The communication feedback data includes the maximum SOC value of the parallel machine, and the self-state data includes the local SOC value; The controller is also used to determine whether to execute the operation of calling the first current loop control strategy according to the set working mode of the power module according to the difference between the maximum SOC value of the parallel machine and the local SOC value; If the difference is within the allowable deviation range, it is determined to maintain the operation of calling the voltage loop control strategy; If the difference is not within the allowable deviation range, it is determined to execute the operation of calling the first current loop control strategy according to the set working mode of the power module.

5. The parallel control device according to claim 4, characterized in that: The communication feedback data includes the average load current; The controller is used to adjust the output current according to the load average current when entering the current sharing mode.

6. The parallel control device according to claim 4, characterized in that: The communication feedback data includes the average load current, the average load SOC value and the number of parallel machines; The controller is used for calculating a first current reference value when entering the equalized charge state mode, if it is determined that the first current value is less than a preset overload current, so as to adjust the output current according to the first current reference value; If it is determined that the first current value is not less than the preset overload current, calculating a second current reference value to adjust the state of charge according to the second current reference value; Wherein, the calculation expression of the first current value is: The first current value = maximum parallel SOC value / (number of parallel machines * average load SOC value) * number of parallel machines * average load current; The calculation expression of the first current reference value is: The first current reference value = local SOC value / (number of parallel machines * average SOC value of load) * number of parallel machines * average current of load; The calculation expression of the second current reference value is: The second current reference value=local SOC value / (number of parallel machines*average SOC value of load)*number of parallel machines*average load current+number of parallel machines*preset parameter value.

7. The parallel control device according to claim 1, characterized in that: Also includes: A step trigger is used to monitor the step current change event of the load; The controller is further configured to call a second current loop control strategy when the step current change event is triggered, so as to control the output current of the power module within the preset current range through the second current loop; Alternatively, a voltage loop control strategy is called to control the output voltage of the power module within a preset voltage range through the voltage loop.

8. The parallel control device according to claim 7, characterized in that: The step trigger is specifically used to determine to trigger the step current change event if it is determined that the integral value of the change amount of the local current value in the own state data within the target time period is within the allowable change range or exceeds the allowable change range.

9. The parallel control device according to claim 8, characterized in that: The controller is further used for: if it is determined that the integral value exceeds the allowable variation range, calling the voltage loop control strategy to control the output voltage of the power module within the preset voltage range through the voltage loop; If it is determined that the integral value is within the allowable variation range, the second current loop control strategy is called to ensure that the output current of the power module is within the preset current range.

10. The parallel control device according to any one of claims 7 to 9, characterized in that: After performing corresponding control according to the step current change event, the controller is further used to determine the working mode of the power module and call the first current loop control strategy to control the balanced output of the power module through the first current loop.

11. The parallel control device according to claim 1, characterized in that: Also includes: The data processing module is used to pre-process the current data and the self-state data in the communication feedback data respectively, and the pre-processed current data and self-state data are used to be input into the controller for processing.

12. The parallel control device according to claim 11, characterized in that: The data processing module is specifically used to filter the self-state data; The data processing module is specifically used to filter the current data in the communication feedback data, and then use a ramp function to converge the filtered current data to obtain updated current data for input into the first current loop.

13. A power module, characterized in that: It comprises the parallel control device as claimed in any one of claims 1 to 12.

14. An energy storage parallel system, characterized in that: It comprises a plurality of power modules as claimed in claim 13, each of the power modules is connected in parallel, and each of the power modules is used to realize a parallel control function through its own parallel control device when in a parallel state.

15. The energy storage parallel system according to claim 14, characterized in that: The parallel system is used to determine one of the power modules as a communication master and the other power modules as communication slaves according to the bus communication protocol adopted between the power modules; The communication host is used to obtain the slave status data of each of the communication slaves, process according to its own status data and the slave status data, obtain communication feedback data, and send the communication feedback data to each of the communication slaves; Each of the power modules is also used to determine whether it is a parallel control master or a parallel control slave according to the communication feedback data; wherein, when serving as the parallel control slave, the parallel control function is realized through its own parallel control device.

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