Energy management control device of common direct current bus multi-machine operation energy storage system

Abstract

The invention discloses a common DC bus multi-machine operation energy storage system energy management control device, which comprises a DC bus, a plurality of loads, a control module, an energy management module and an energy storage module, and is characterized in that the input end group of the control module is electrically connected with a plurality of power sensors; the signal output end of the control module is connected with the control signal input end of an energy management module, the energy management module is electrically connected with a first switching module through a DC / DC conversion module, the first switching module is electrically connected with each load, and the energy management module is electrically connected with a first conversion module. The control module judges the working state of each load according to the real-time power data of each load acquired by the power sensor, and when the power value of a certain load is smaller than a second power preset threshold value, the load can be judged to be in a braking state; and braking energy generated by braking of the load is transferred to the energy storage module for storage through the first switching module and the DC / DC conversion module.

Description

Technical Field

[0001] This invention relates to the field of energy management and control technology, specifically to an energy management and control device for a multi-unit energy storage system operating on a common DC bus. Background Technology

[0002] With the increasing automation of industrial production, multi-motor drive systems are widely used in manufacturing. Each motor operates in both driving and braking states during operation. The energy generated during braking is largely consumed as heat, resulting in significant energy loss. An effective solution is to use a common DC bus configuration to centrally control and manage energy, enabling self-consumption of energy among loads and greatly improving system energy utilization. However, this method still has the problem of excessive braking energy that the system cannot consume internally. The excess braking energy will still accumulate at the DC bus, causing a voltage surge.

[0003] Therefore, Chinese patent CN202011270303.7 proposes an energy management and control device for a multi-machine energy storage system operating on a common DC bus to solve the above problems. However, this device suffers from drawbacks such as multiple steps, complex control logic, low reliability, and high implementation difficulty when coordinating energy distribution between the motor in braking and motoring states. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an energy management and control device for a multi-unit energy storage system operating on a common DC bus, thus solving the problems mentioned in the background section.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an energy management and control system for a multi-unit energy storage system operating on a common DC bus, comprising a DC bus, multiple loads, a control module, an energy management module, and an energy storage module. The input terminals of the control module are electrically connected to multiple power sensors. The signal output terminal of the control module is connected to the control signal input terminal of the energy management module. The energy management module is electrically connected to a first switching module via a DC / DC conversion module. The first switching module is electrically connected to each load. The energy management module is electrically connected to a first conversion module. The first conversion module is electrically connected to a second switching module. The second switching module is connected to the power input terminal of each load. Both the first and second switching modules are electrically connected to the control module. The energy management module is electrically connected to the energy storage module.

[0006] Preferably, the DC bus is electrically connected to a plurality of second conversion modules, the second conversion modules are electrically connected to a power distribution module, the power distribution module is electrically connected to the load, a first current detection module is provided between the power distribution module and the load, a current limiting energy-saving device is provided between the energy management module and the energy storage module, and a second current detection module is provided between the second switching module and the load.

[0007] Preferably, the control module is electrically connected to the plurality of loads, the control module is electrically connected to a voltage and current detection module, and the voltage and current detection module is electrically connected to the DC bus and the AC / DC conversion module.

[0008] Preferably, the energy management module includes a charging management unit, a discharging management unit, and a control execution unit. The control execution unit is electrically connected to the energy storage module, the control module, the charging management unit, and the discharging management unit, respectively. The charging management unit is electrically connected to the DC / DC conversion module, and the discharging management unit is electrically connected to the first conversion module.

[0009] Beneficial effects This invention provides an energy management and control device for a multi-unit energy storage system operating on a common DC bus. Compared with the prior art, it has the following advantages: 1. The energy management and control device of the multi-unit operation energy storage system with a common DC bus, the control module judges the working status of each load according to the real-time power data of each load obtained by the power sensor. When the power value of a certain load is less than the second preset power threshold, it can be judged that the load is in a braking state. In this state, the braking energy needs to be transferred to avoid the braking energy causing the DC bus energy to accumulate and cause the DC bus voltage to rise. The control module sends a control signal to the first switching module and the energy management module to make the connection between the load and the DC / DC conversion module, and between the charging management unit and the energy storage module, so as to realize the transfer of the braking energy generated by the braking of the load to the energy storage module for storage through the first switching module and the DC / DC conversion module.

[0010] 2. The energy management and control device of the multi-unit energy storage system operating on a common DC bus, the control module judges the working status of each load based on the real-time power data of each load obtained by the power sensor. When the power value of a load is greater than the first preset power threshold, it can be judged that the load is in full-load working state. The control module sends a control signal to the second switching module and the energy management module, so that the energy storage module and the discharge management unit, as well as the second switching module and the load, are connected. The electrical energy stored in the energy storage module is delivered to the full-load load through the first conversion module and the second switching module, which can reduce the load of the entire power supply system. At the same time, the first current detection module detects the current used by the load, and the second current detection module detects the current output of the energy storage module. Then the data is transmitted to the control module. The control module compares the current of the load with the current of the full-load load to obtain the difference, and then controls the current limiting device to limit the current released by the energy storage module to prevent energy waste.

[0011] 3. The energy management and control device of the multi-unit energy storage system with a common DC bus, under normal load conditions, measures the DC bus voltage and the three-phase voltage and three-phase current at the output side of the AC / DC conversion module using a voltage and current detection module; reconstructs the DC bus current based on the three-phase voltage and three-phase current at the output side of the AC / DC conversion module; and estimates the DC bus capacitance value using a recursive least squares method based on the DC bus voltage and the reconstructed DC bus current. The specific steps for estimating the DC bus capacitance value using the recursive least squares method based on the DC bus voltage and the reconstructed DC bus current are described in the following formula. This improves estimation accuracy and ensures the DC bus capacitance can operate normally without affecting the stable operation of the load. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the energy management module in this invention.

[0013] In the diagram: 1. DC bus; 2. AC / DC conversion module; 3. Second conversion module; 4. Power distribution module; 5. Load; 6. Power sensor; 7. Control module; 8. Second switching module; 9. First conversion module; 10. Energy management module; 11. Energy storage module; 12. First switching module; 13. DC / DC conversion module; 14. Voltage and current detection module; 15. Charging management unit; 16. Discharging management unit; 17. Control execution unit; 18. First current detection module; 19. Current limiting and energy saving device; 20. Second current detection module. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] Please see Figure 1-2 This invention provides a technical solution: an energy management and control system for a multi-unit operating energy storage system with a common DC bus, comprising a DC bus 1, multiple loads 5, a control module 7, an energy management module 10, and an energy storage module 11. Multiple power sensors 6 are electrically connected to the input terminals of the control module 7. The signal output terminal of the control module 7 is connected to the control signal input terminal of the energy management module 10. The energy management module 10 is electrically connected to a first switching module 12 via a DC / DC conversion module 13. The first switching module 12 is electrically connected to each load 5. The energy management module 10 is also electrically connected to a first conversion module 9. The first conversion module 9 is electrically connected to a second switching module 8, which is connected to the power input terminal of each load 5. Both the first switching module 12 and the second switching module 8 are electrically connected to the control module 7. The energy management module 10... The DC bus 1 is electrically connected to the energy storage module 11, and multiple second conversion modules 3 are electrically connected to the DC bus 1. The second conversion modules 3 are electrically connected to the power distribution module 4. The power distribution module 4 is electrically connected to the load 5. A first current detection module 18 is provided between the power distribution module 4 and the load 5. A current limiting and saving device 19 is provided between the energy management module 10 and the energy storage module 11. A second current detection module 20 is provided between the second switching module 8 and the load 5. The energy management module 10 includes a charging management unit 15, a discharging management unit 16 and a control execution unit 17. The control execution unit 17 is electrically connected to the energy storage module 11, the control module 7, the charging management unit 15 and the discharging management unit 16 respectively. The charging management unit 15 is electrically connected to the DC / DC conversion module 13. The discharging management unit 16 is electrically connected to the first conversion module 9. In Example 1, the control module 7 judges the working status of each load 5 based on the real-time power data of each load 5 obtained by the power sensor 6. When the power value of a certain load 5 is less than the second power preset threshold, it can be determined that the load 5 is in a braking state. In this state, the braking energy needs to be transferred to avoid the braking energy causing the DC bus 1 to accumulate energy and cause the DC bus 1 voltage to rise. The control module 7 sends a control signal to the first switching module 12 and the energy management module 10, so that the load 5 and the DC / DC conversion module 13 are connected, and the charging management unit 15 and the energy storage module 11 are connected, so as to realize the braking energy generated by the braking of the load 5 is transferred to the energy storage module 11 for storage through the first switching module 12 and the DC / DC conversion module 13. In Example 2, the control module 7 judges the working status of each load 5 based on the real-time power data of each load 5 obtained by the power sensor 6. When the power value of a certain load 5 is greater than the first power preset threshold, it can be determined that the load 5 is in a full-load working state. The control module 7 sends a control signal to the second switching module 8 and the energy management module 10, so that the energy storage module 11 and the discharge management unit 16, as well as the second switching module 8 and the load 5, are connected. The electrical energy stored in the energy storage module 11 is transmitted to the fully loaded load 5 through the first conversion module 9 and the second switching module 8, which can reduce the load of the entire power supply system. At the same time, the first current detection module 18 detects the current used by the load 5, and the second current detection module 20 detects the current output by the energy storage module 11. Then the data is transmitted to the control module 7. The control module 7 compares the current of the load 5 with the current of the full-load load 5 to obtain the difference. Then the current limiting device 19 is controlled to limit the current of the energy released by the energy storage module 11 to prevent energy waste. Furthermore, the control module 7 is electrically connected to multiple loads 5, and the control module 7 is electrically connected to a voltage and current detection module 14. The voltage and current detection module 14 is electrically connected to the DC bus 1 and the AC / DC conversion module 2. Example 3: Under normal operating conditions of load 5, the voltage and current detection module 14 measures the voltage of DC bus 1 and the three-phase voltage and three-phase current at the output side of AC / DC conversion module 2; the current of DC bus 1 is reconstructed based on the three-phase voltage and three-phase current at the output side of AC / DC conversion module 2; based on the voltage of DC bus 1 and the reconstructed current of DC bus 1, the capacitance value of DC bus 1 is estimated using the recursive least squares method; the specific steps for estimating the capacitance value of DC bus 1 using the recursive least squares method based on the voltage of DC bus 1 and the reconstructed current of DC bus 1 are performed using the following formula; the specific steps for estimating the capacitance value of DC bus 1 using the recursive least squares method based on the voltage of DC bus 1 and the reconstructed current of DC bus 1 are performed using the following formula: ;in, Indicates the first The estimated DC bus 1 capacitance value from each sampling point Greater than or equal to 1 Indicates the gain coefficient. Indicates the estimation error; The calculation formula is: Where P(n) represents the nth The intermediate coefficients of each sampling point Indicates the first The rate of change of DC bus 1 voltage measured at each sampling point The calculation formula is: , The calculation formula is: , Indicates the first The DC bus voltage value measured at each sampling point. Indicates time; The calculation formula is: ,in, Indicates the first The reconstructed DC bus 1 current value obtained from the measurements at each sampling point The calculation formula is: This allows for real-time online estimation of the DC bus 1 capacitor. Furthermore, the recursive least squares method results in a more accurate estimation, thus improving estimation precision. This ensures that the DC bus 1 capacitor can operate normally without affecting the stable operation of load 5.

[0016] Furthermore, any content not described in detail in this specification is existing technology known to those skilled in the art.

[0017] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, the phrase "comprising an element defined as..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0018] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An energy management and control device for a multi-unit energy storage system operating on a common DC bus, characterized in that, The system includes a DC bus (1), multiple loads (5), a control module (7), an energy management module (10), and an energy storage module (11). The input terminals of the control module (7) are electrically connected to multiple power sensors (6). The signal output terminals of the control module (7) are connected to the control signal input terminals of the energy management module (10). The energy management module (10) is electrically connected to a first switching module (12) via a DC / DC conversion module (13). The first switching module (12) is electrically connected to each load (5). The energy management module (10) is electrically connected to a first conversion module (9). The first conversion module (9) is electrically connected to a second switching module (8). The second switching module (8) is connected to the power input terminals of each load (5). Both the first switching module (12) and the second switching module (8) are electrically connected to the control module (7). The energy management module (10) is electrically connected to the energy storage module (11).

2. The energy management and control device for a multi-unit energy storage system operating on a common DC bus as described in claim 1, characterized in that: The DC bus (1) is electrically connected to multiple second conversion modules (3), and the second conversion modules (3) are electrically connected to a power distribution module (4). The power distribution module (4) is electrically connected to the load (5). A first current detection module (18) is provided between the power distribution module (4) and the load (5). A current limiting and energy saving device (19) is provided between the energy management module (10) and the energy storage module (11). A first current detection module (18) is provided between the power distribution module (4) and the load (5). A current limiting and energy saving module (19) is provided between the energy management module (10) and the energy storage module (11). A second current detection module (20) is provided between the second switching module (8) and the load (5).

3. The energy management and control device for a multi-unit energy storage system operating on a common DC bus as described in claim 2, characterized in that: The control module (7) is electrically connected to the multiple loads (5), and the control module (7) is electrically connected to a voltage and current detection module (14). The voltage and current detection module (14) is electrically connected to the DC bus (1) and the AC / DC conversion module (2).

4. The energy management and control device for a multi-unit energy storage system operating on a common DC bus as described in claim 3, characterized in that: The energy management module (10) includes a charging management unit (15), a discharging management unit (16), and a control execution unit (17). The control execution unit (17) is electrically connected to the energy storage module (11), the control module (7), the charging management unit (15), and the discharging management unit (16), respectively. The charging management unit (15) is electrically connected to the DC / DC conversion module (13), and the discharging management unit (16) is electrically connected to the first conversion module (9).

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