Modularized integrated energy storage system and dynamic cooperative control method thereof

Abstract

The invention discloses a modular integrated energy storage system and a dynamic cooperative control method thereof, and the dynamic cooperative control method comprises the steps: segmenting according to the total power of the system, and improving the efficiency of the system through the cooperative cooperation of adjusting the number of operation modules and switching modulation modes. The lower the total power of the system is, the less the number of modules put into operation is. And adjusting a module switching instruction according to the accumulated working time, preferentially switching on the power module with the shorter accumulated working time, and preferentially switching off the power module with the longest accumulated working time. The main controller is provided with a power detection unit, a dormancy management unit and a modulation switching unit; the power detection unit monitors the total power Pset of the system in real time; the modulation switching unit determines a modulation mode and the number of operation modules according to the total power Pset of the system; and the dormancy management unit counts the accumulated working time of each module, and adjusts a module switching instruction according to the accumulated working time. According to the invention, the capability of maintaining high-efficiency output of the modularized integrated energy storage system in a full power section can be improved.

Description

Technical Field

[0001] The present invention relates to the field of new energy storage and power electronics technology, and in particular to a dynamic collaborative control method for a modular integrated energy storage system and a modular integrated energy storage system adopting the control method. Background Art

[0002] The modular, integrated energy storage system primarily consists of energy storage batteries, a modular energy storage converter (PCS), a battery management system (BMS), an energy management system (EMS), a temperature control system, fire protection, and security systems. The modular energy storage converter (PCS), as the core component of the integrated energy storage system, enables bidirectional power conversion between the energy storage system and the main grid, improving the quality and reliability of the microgrid's power supply. The energy management system (EMS) acts as the brain of the energy storage system, monitoring, controlling, and optimizing its operation, providing efficient and stable energy management. Therefore, effective coordination and control between the energy storage converter and the energy management system, as well as between them, are crucial for ensuring the efficient and safe operation of the energy storage system.

[0003] In traditional modular integrated energy storage systems, when performing power control, the energy management system issues power control commands. Upon receiving these commands, the modular energy storage inverter distributes its power evenly to each module, achieving power control output. This control approach can cause all modules to operate in light-load mode during low- to medium-power operation, resulting in low energy storage system conversion efficiency. Furthermore, the traditional rotating switching control strategy of modular inverters relies solely on switching modules in a fixed sequence, resulting in some modules experiencing significantly higher cumulative operating hours than others.

[0004] Secondly, traditional energy storage converter control methods use a single modulation method, either fixed continuous pulse width modulation (SVPWM) or discontinuous pulse width modulation (DPWM), across the entire power range. SVPWM boasts high maturity, ease of digitization, and low harmonic THD, but relatively low system conversion efficiency. Discontinuous pulse width modulation (DPWM) offers high conversion efficiency but suffers from high harmonic THD at low and medium power levels, making it difficult to meet grid connection standards. Therefore, traditional energy storage systems operating over a wide power range use a single modulation method, resulting in high switching losses and low efficiency at light loads. Under heavy loads, the need for harmonic suppression and efficiency become increasingly conflicting.

[0005] Therefore, in view of the shortcomings of the existing technology, it is necessary to provide a modular integrated energy storage system dynamic collaborative control method and a modular integrated energy storage system using the control method to overcome the shortcomings of the existing technology. Summary of the Invention

[0006] The purpose of the present invention is to avoid the shortcomings of the existing technology and provide a modular integrated energy storage system dynamic collaborative control method, which can improve the ability of the modular integrated energy storage system to maintain high-efficiency output in the full power range.

[0007] The purpose of the present invention is achieved through the following technical measures.

[0008] A dynamic collaborative control method for a modular integrated energy storage system is provided. According to the total power segmentation of the system, the system efficiency is improved by adjusting the number of operating modules and coordinating the switching of modulation modes.

[0009] Preferably, in the above-mentioned dynamic coordinated control method of the modular integrated energy storage system, the modulation mode is switched specifically to SVPWM or DPWM.

[0010] Preferably, in the above-mentioned dynamic coordinated control method of the modular integrated energy storage system, the lower the total system power, the fewer the number of modules put into operation.

[0011] Preferably, the above-mentioned dynamic collaborative control method of the modular integrated energy storage system counts the cumulative working time of each module, adjusts the module switching instructions according to the cumulative working time, gives priority to switching on power modules with shorter cumulative working time, and gives priority to switching off power modules with the longest cumulative working time.

[0012] Preferably, in the above-mentioned dynamic collaborative control method for the modular integrated energy storage system, the main controller adopts a dynamic collaborative control method for control.

[0013] Preferably, in the above-mentioned modular integrated energy storage system dynamic collaborative control method, the main controller is provided with a power detection unit, a sleep management unit and a modulation switching unit;

[0014] The power detection unit monitors the total system power Pset in real time;

[0015] The modulation switching unit determines the modulation mode and the number of operating modules according to the total system power Pset;

[0016] The sleep management unit counts the cumulative working time of each module and adjusts the module switching instructions according to the cumulative working time.

[0017] Preferably, in the above-mentioned dynamic coordinated control method for the modular integrated energy storage system, the modulation switching unit statistics triggers the switching control mode when the power exceeds the threshold for 5 seconds.

[0018] Preferably, in the above-mentioned dynamic coordinated control method of the modular integrated energy storage system, the modular integrated energy storage system has three-module converters, and the AC and DC sides of the three modules adopt a parallel control mode;

[0019] The main controller integrates a power detection unit, a sleep management unit, and a modulation switching unit to monitor the total system power Pset in real time and determine the power range. The dynamic collaborative control logic of the main controller is as follows:

[0020] The power detection unit monitors the total system power, Pset, in real time. When Pset is less than 30%, SVPWM is enabled, enabling one module to operate. When 30% ≤ Pset < 60%, DPWM is enabled, enabling two modules to operate. When Pset is ≥ 60%, DPWM is enabled, enabling three modules to operate. The sleep management unit calculates the cumulative operating time of each module and adjusts module switching instructions based on this cumulative operating time, prioritizing the switching of power modules with the shortest cumulative operating time and the disconnection of power modules with the longest cumulative operating time.

[0021] The present invention also provides a modular integrated energy storage system that adopts the above-mentioned dynamic coordinated control method.

[0022] The present invention's dynamic coordinated control method for a modular, integrated energy storage system improves system efficiency by adjusting the number of operating modules and switching modulation modes according to the system's total power segmentation. This method enhances the modular, integrated energy storage system's ability to maintain high-efficiency output across the full power range. Applicable to integrated energy storage systems with multiple modules connected in parallel, this method addresses the widespread issues of low system efficiency, high switching losses, and energy waste caused by redundant module operation.

[0023] Figures in the specification

[0024] The present invention is further described with reference to the accompanying drawings, but the contents in the drawings do not constitute any limitation to the present invention.

[0025] Figure 1 This is a schematic diagram of the modulation switching control strategy of a module in a modular integrated energy storage system collaborative control method of the present invention.

[0026] Figure 2 This is a logic diagram of intelligent body sleep control in a modular integrated energy storage system dynamic collaborative control method of the present invention. DETAILED DESCRIPTION

[0027] The present invention will be further described with reference to the following examples.

[0028] Example 1.

[0029] A dynamic collaborative control method for a modular integrated energy storage system improves system efficiency by adjusting the number of operating modules and coordinating the switching of modulation modes according to the total system power segmentation, thereby achieving a balanced optimization of efficiency and harmonics.

[0030] The modulation mode switching is specifically to select SVPWM (continuous pulse width modulation) or DPWM (discontinuous pulse width modulation). In this modular integrated energy storage system dynamic collaborative control method, the lower the total system power, the fewer modules are put into operation.

[0031] This modular integrated energy storage system dynamic collaborative control method counts the cumulative working time of each module and adjusts the module switching instructions according to the cumulative working time, giving priority to switching on power modules with shorter cumulative working time and prioritizing switching off power modules with the longest cumulative working time.

[0032] The modular integrated energy storage system adopts a dynamic collaborative control method, and the main controller adopts a dynamic collaborative control method for control.

[0033] The main controller is equipped with a power detection unit, a sleep management unit, and a modulation switching unit. The power detection unit monitors the total system power Pset in real time. The modulation switching unit determines the modulation mode and the number of operating modules based on the total system power Pset. The sleep management unit counts the cumulative operating time of each module and adjusts the module switching instructions based on the accumulated operating time.

[0034] This modular integrated energy storage system dynamic collaborative control method modulates the switching unit statistics to trigger the switching control mode when the power exceeds the threshold for 5 seconds continuously, avoiding frequent switching due to power fluctuations and sampling errors.

[0035] Traditional solutions achieve power distribution only through fixed module rotation (quantity control) or fixed modulation methods (such as full-range SVPWM). However, this invention adopts dynamic coordinated control to dynamically couple the two. Divide by power segment: The number of modules and the modulation method are adjusted in conjunction to avoid light-load efficiency loss and excessive heavy-load harmonics. Module life balance: By counting the accumulated working hours of the modules, the switching order is dynamically adjusted (prioritizing the start and stop of modules with low working hours) to avoid excessive wear and tear on a single module.

[0036] This invention combines module dormancy with modulation mode control for the first time, breaking through the efficiency bottleneck of a single dimension, achieving high-efficiency output across the entire power range and improving the charging and discharging benefits of the energy storage system.

[0037] Module sleep control automatically switches on or off some modules according to the load power, avoiding long-term light-load operation of modules and improving the overall efficiency of the system. At the same time, it balances the working time between modules, avoiding long-term overload operation of some modules, reducing failure rate and extending module service life.

[0038] The modulation mode control is based on the efficiency intersection point of different modulation modes, and dynamically adjusts the switching threshold to achieve high-efficiency output in the full power range.

[0039] The solution of the present invention improves efficiency, effectively suppresses harmonics, and extends the overall system lifespan. This method reduces the number of operating modules in the low-power range, adopts high-efficiency DPWM in the mid- and high-power ranges, and flattens the efficiency curve across the entire power range. By combining the number of modules with the modulation method, multiple modules are connected in parallel to offset harmonics within the high-efficiency range of DPWM. An intelligent sleep strategy prevents significant differences in operating hours between modules, extending the overall system lifespan.

[0040] Example 2.

[0041] A method for dynamic coordinated control of a modular integrated energy storage system. In this embodiment, the modular integrated energy storage system has three-module converters, and the AC and DC sides of the three modules adopt a parallel control mode.

[0042] The main controller integrates a power detection unit, a sleep management unit, and a modulation switching unit to monitor the total system power Pset in real time and determine the power range. The dynamic collaborative control logic of the main controller is as follows:

[0043] The power detection unit monitors the total system power Pset in real time. When Pset < 30%, SVPWM is enabled and one module is enabled for operation; when 30% ≤ Pset < 60%, DPWM is enabled and two modules are enabled for operation; when Pset ≥ 60%, DPWM is enabled and three modules are enabled for operation.

[0044] When Pset < 30%, only one module is activated and the rest are in sleep mode. SVPWM (continuous pulse width modulation) is used for modulation. At this point, the system is in a low-power scenario, and the total system power demand is low (< 30% of rated power). If all modules are running, all modules will be lightly loaded (low efficiency). Although SVPWM has low efficiency, its harmonic characteristics are good (low THD), making it suitable for grid connection requirements under low power conditions. Running only one module avoids the cumulative loss of multiple modules with light loads, and the load rate of a single module is increased to nearly 30%, allowing it to operate in a relatively high-efficiency range.

[0045] When 30% ≤ Pset < 60%, two modules are activated for operation and one is put into sleep mode, using DPWM (discontinuous pulse width modulation). In this state, the system is in a medium-power scenario, and the total power is increased to 30% to 60%, requiring a balance between efficiency and harmonics. DPWM reduces switching losses and improves efficiency by reducing the number of switches (turning off the device for part of the time period); however, DPWM harmonics are large, so it is necessary to increase the number of operating modules (two modules in parallel) to share the power, reducing the load rate of a single module to 15% to 30%, reducing the harmonic amplitude (the harmonic phase staggering of parallel modules can partially offset it), and effectively ensuring efficiency. This avoids the existing technology of using SVPWM + 3 modules, where the load rate of all modules is only 10% to 20%, which is extremely inefficient.

[0046] When Pset ≥ 60%, all three modules are activated and DPWM modulation continues to be used. The total power demand is high (≥ 60%), and efficiency must be maximized while meeting harmonic limits. DPWM has significant efficiency advantages under high loads (the proportion of switching losses is reduced). The three modules share power equally, with a single module load factor of approximately 20% to 33%. The harmonic amplitude is further reduced (the harmonic cancellation effect of parallel modules is enhanced), meeting grid connection standards.

[0047] Taking any module i in the three-module converter as an example, the modulation switching control strategy principle of module i is as follows: Figure 1 shown.

[0048] Figure 1 The modulation switching control closed loop of module i is demonstrated. Its core is to achieve high efficiency and low harmonic output through dynamic modulation mode selection (SVPWM / DPWM) and current closed-loop control. The input is the total system power command Pset (from the energy management system EMS). The output is the PWM modulation signal of module i, which drives the converter switching devices.

[0049] Key component functions are as follows:

[0050] (1) Power-current conversion (PT and PLC)

[0051] PT (Power Tracking): Decomposes the total system power command Pset into the reference current I of module i i,ref , considering the module sleep state (such as when the total power is <30% only one module is running,

[0052] I i,ref =Pset / Vdc).

[0053] PLC (Power Logic Controller): Dynamically switches the modulation mode (SVPWM / DJWM) and module switching instructions according to the power range (such as 30% and 60%).

[0054] (2) Current closed-loop control (PI and dqo conversion)

[0055] abc / dqo conversion: convert the three-phase AC current I abc Converted to DC quantity I in rotating coordinate system d ,I q , eliminating the complexity of AC quantity control.

[0056] PI controller: adjusts I d ,I q The error, output modulation wave signal V d ,V q , and then generate a three-phase modulated wave through inverse DQO transformation.

[0057] (3) Modulation mode switching (DPWM / SVPWM): Select the modulation mode according to the power range.

[0058] The specific collaborative control strategy and the linkage of module i are as follows:

[0059] (1) Power segment control

[0060] Low power range (Pset < 30%): If module i is activated, SVPWM is used to ensure low harmonics (meeting grid connection standards). At this time, only one module is running and the others are dormant to avoid light load losses of multiple modules.

[0061] Medium power range (30% ≤ Pset < 60%): Switch to DPWM to improve efficiency. Two modules run simultaneously to share power and reduce the harmonic amplitude of each module.

[0062] High power range (Pset ≥ 60%): Maintain DPWM, all three modules are running, maximizing efficiency and offsetting harmonics through parallel connection.

[0063] When module i is put into sleep mode or the modulation mode is switched, the integrator is reset to avoid current shock during restart due to accumulated error.

[0064] System-level coordination is coordinated through the master controller, ensuring global synchronization of modulation methods. The master controller, through the power detection unit and sleep management unit, issues module switching commands to each module's PLC, ensuring balanced operating hours across modules (with low-operating-hour modules prioritized). All operating modules uniformly switch to the same modulation method (e.g., DPWM in the mid-power range) to avoid circulating currents or harmonic superposition caused by modulation differences.

[0065] By switching between modulation modes (SVPWM / DPWM) and adjusting the number of modules in each power segment, efficiency across the entire power range is improved by 10%-15%, and harmonic distortion (THD) is reduced to within grid-connected standards (<5%). This achieves a balanced efficiency and harmonic balance. Module operating time statistics and intelligent switching extend system life by over 20%. Integrator reset and PLC logic ensure stability during modulation mode switching, with a transition time of <10ms, enabling fast response.

[0066] The sleep management unit counts the cumulative working time of each module and adjusts the module switching instructions according to the cumulative working time, giving priority to switching on the power module with the shorter cumulative working time and giving priority to switching off the power module with the longest cumulative working time. The principle diagram is as follows Figure 2 The modulation switching unit counts that when the power exceeds the threshold for 5 seconds, it triggers the switching control mode to avoid frequent switching due to power fluctuations and sampling errors.

[0067] This invention combines module dormancy with modulation mode control for the first time, breaking through the efficiency bottleneck of a single dimension, achieving high-efficiency output across the entire power range and improving the charging and discharging benefits of the energy storage system.

[0068] Module sleep control automatically switches on or off some modules according to the load power, avoiding long-term light-load operation of modules and improving the overall efficiency of the system. At the same time, it balances the working time between modules, avoiding long-term overload operation of some modules, reducing failure rate and extending module service life.

[0069] The modulation mode control is based on the efficiency intersection point of different modulation modes, and dynamically adjusts the switching threshold to achieve high-efficiency output in the full power range.

[0070] The solution of the present invention can improve efficiency, effectively suppress harmonics, and increase the overall life of the system.

[0071] Example 3.

[0072] The present invention also provides a modular, integrated energy storage system that utilizes the dynamic coordinated control method of Example 1 or 2. This system achieves high-efficiency output across the entire power range, improving the charging and discharging efficiency of the energy storage system. This solution improves efficiency, effectively suppresses harmonics, and extends the overall lifespan of the system.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A modular integrated energy storage system dynamic collaborative control method, characterized by: According to the total system power segmentation, the system efficiency is improved by adjusting the number of operating modules and coordinating the switching of modulation modes.

2. The modular integrated energy storage system dynamic coordinated control method according to claim 1, characterized in that: The modulation mode switching is specifically selecting to switch to SVPWM or DPWM.

3. The method for dynamic coordinated control of a modular integrated energy storage system according to claim 2, characterized in that: The lower the total system power, the fewer modules are put into operation.

4. The method for dynamic coordinated control of a modular integrated energy storage system according to any one of claims 1 to 3, characterized in that: The accumulated working time of each module is counted, and the module switching instructions are adjusted according to the accumulated working time. The power modules with shorter accumulated working time are prioritized, and the power modules with the longest accumulated working time are prioritized.

5. The method for dynamic coordinated control of a modular integrated energy storage system according to claim 4, characterized in that: The main controller adopts dynamic cooperative control method for control.

6. The method for dynamic coordinated control of a modular integrated energy storage system according to claim 5, characterized in that: The main controller is provided with a power detection unit, a sleep management unit and a modulation switching unit; The power detection unit monitors the total system power Pset in real time; The modulation switching unit determines the modulation mode and the number of operating modules according to the total system power Pset; The sleep management unit counts the cumulative working time of each module and adjusts the module switching instructions according to the cumulative working time.

7. The method for dynamic coordinated control of a modular integrated energy storage system according to claim 6, characterized in that: The modulation switching unit statistics triggers the switching control mode when the power exceeds the threshold for 5 seconds.

8. The method for dynamic coordinated control of a modular integrated energy storage system according to claim 7, characterized in that: The modular integrated energy storage system is configured as a three-module converter, with the AC and DC sides of the three modules adopting a parallel control mode; The main controller integrates a power detection unit, a sleep management unit, and a modulation switching unit to monitor the total system power Pset in real time and determine the power range. The dynamic collaborative control logic of the main controller is as follows: When Pset<30%, SVPWM is enabled and one module is enabled for operation; when 30%≤Pset<60%, DPWM is enabled and two modules are enabled for operation; when Pset≥60%, DPWM is enabled and three modules are enabled for operation.

9. A modular integrated energy storage system, characterized in that: A dynamic collaborative control method as described in any one of claims 1 to 8 is adopted.

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