Network construction type distributed energy storage system

Abstract

The invention discloses a network construction type distributed energy storage system, which comprises a battery module, a network construction type power module and an energy storage management system, the battery module comprises a plurality of battery cells which are connected in series and a plurality of corresponding battery cell acquisition systems, and the net-forming type power module comprises a plurality of sub power modules corresponding to the battery cells. According to the application, the electrical core charge state is acquired through the electrical core acquisition system, the energy storage management system sends the preset operation parameters to the sub-power modules, and the sub-power modules acquire the three-phase voltage and current data of the corresponding electrical cores and the bus voltage data of the grid-connected point of the power station; and generating adjustment parameters according to the three-phase voltage and current data, the bus voltage data, preset operation parameters and the state of charge of the battery cell, generating an active control instruction and a reactive control instruction based on the adjustment parameters, and performing comprehensive control by the energy storage management system according to the active control instruction and the reactive control instruction. And the control precision and the control efficiency of the energy storage system are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage systems, and in particular to a grid-type distributed energy storage system. Background Art

[0002] With the rapid development of distributed renewable energy generation technology, the volatility of renewable energy generation has brought a series of challenges to the power system. Electrochemical energy storage systems are generally used to store and control renewable energy generation to ensure grid stability and improve the peak load, frequency and voltage regulation capabilities of the power system. At present, conventional electrochemical energy storage system converters are controlled based on current source logic and cannot provide active support for the stable operation of the grid.

[0003] In the prior art, the patent publication number CN115085252A, "A photovoltaic optimization network construction method for distribution network system", sets a photovoltaic network construction switch; sets a low-voltage distributed photovoltaic centralized network construction terminal; transforms the medium-voltage centralized photovoltaic inverter; sets a medium-voltage photovoltaic fast frequency / voltage support device; performs distribution network AVC photovoltaic group control transformation; performs power generation and load forecasting for main distribution coordination; collects data and performs predictive control based on data interaction relationships. By improving the friendly interaction ability of distributed photovoltaics with the power grid, the generalized virtual synchronization technology of medium and low voltage distributed photovoltaics is upgraded, the photovoltaic MPPT regulation potential and the DC bus capacitor energy of the inverter are fully tapped, and the inverter AC side output transient power is quickly adjusted according to the changes in the voltage and frequency of the power grid, providing active support for the power grid and realizing timely control of the power grid.

[0004] The above-mentioned existing energy storage control method will introduce delays in the transient process, and there is a risk of exacerbating the fluctuation amplitude of low voltage or overvoltage in the system. The control accuracy and control efficiency of the energy storage system are poor. Summary of the invention

[0005] The present invention provides a grid-type distributed energy storage system to solve the problem in the prior art that there is no relatively reliable control accuracy and control efficiency of the energy storage system.

[0006] On the one hand, the present invention provides a grid-type distributed energy storage system, including: a battery module, a grid-type power module and an energy storage management system.

[0007] The battery module includes a plurality of battery cells connected in series and a corresponding plurality of battery cell collection systems, and the networked power module includes a plurality of sub-power modules corresponding to the battery cells.

[0008] The battery cell collection system is used to collect the charge state of the battery cells.

[0009] The energy storage management system is used to send preset operating parameters to the sub-power module.

[0010] The sub-power module is also used to collect the three-phase voltage and current data of the corresponding battery cell and the bus voltage data of the power station grid connection point, generate adjustment parameters according to the three-phase voltage and current data, the bus voltage data, the preset operating parameters, and the battery cell charge state, and generate active control instructions and reactive control instructions based on the adjustment parameters.

[0011] The energy storage management system is also used to perform comprehensive control according to the active power control instruction and the reactive power control instruction.

[0012] In a possible implementation, the sub-power module is further configured to obtain a bus voltage deviation according to the bus voltage data and a preset bus voltage reference value.

[0013] The sub-power module is also used to generate an adjustment parameter when the bus voltage deviation is greater than a preset bus voltage deviation threshold, and to generate an active control instruction and a reactive control instruction based on the adjustment parameter.

[0014] The adjustment parameters include: reference three-phase voltage and current and reference reactive power.

[0015] In a possible implementation, the sub-power module is further used to generate a voltage phase control instruction value, namely, the active power control instruction, according to the state of charge of the battery cell, the three-phase voltage and current data, and the reference three-phase voltage and current.

[0016] The sub-power module is further used to generate a voltage amplitude control instruction value, namely, the reactive power control instruction, according to the bus voltage deviation and the reference reactive power.

[0017] The energy storage management system is also used to generate an internal potential control command value according to the voltage phase control command value and the voltage amplitude control command value, and perform internal potential control.

[0018] In a possible implementation, the preset operating parameters include: preset active power, preset reactive power, target frequency difference, and target voltage difference.

[0019] The sub-power module is further used to obtain the adjusted active power according to the preset active power and the target frequency difference, and to obtain the adjusted reactive power according to the preset reactive power and the target voltage difference.

[0020] The sub-power module is also used to obtain the reference three-phase voltage and current and the reference reactive power, that is, the adjustment parameters, according to the adjusted active power and the adjusted reactive power.

[0021] In a possible implementation manner, the preset operating parameters also include: a preset frequency.

[0022] The energy storage management system is also used to collect the battery cell AC frequency, and determine the target frequency difference according to the frequency difference between the battery cell AC frequency and the preset frequency.

[0023] In a possible implementation manner, the preset operating parameters also include: a preset voltage.

[0024] The energy storage management system is also used to collect the battery cell AC voltage and determine the target voltage difference according to the voltage difference between the battery cell AC voltage and the preset voltage.

[0025] In a possible implementation, the energy storage management system is further configured to generate an active power correction factor according to the state of charge of the battery cell and the rated capacity of the battery cell.

[0026] The energy storage management system is also used to construct a grid-type energy storage active power control model based on the traditional synchronous generator rotor motion equation, and set the active power correction coefficient in the grid-type energy storage active power control model.

[0027] In a possible implementation, the energy storage management system is also used to construct a reactive voltage droop control link and establish a grid-type energy storage reactive power control model according to the voltage regulation characteristics of a traditional synchronous generator.

[0028] In a possible implementation, the energy storage management system is also used to construct a voltage outer-loop proportional-integral control link and a current inner-loop proportional-integral control link according to a preset proportional-integral control strategy, and to establish a grid-type energy storage comprehensive control model based on the voltage outer-loop proportional-integral control link and the current inner-loop proportional-integral control link.

[0029] A grid-type distributed energy storage system in the present invention has the following advantages: The battery cell charge state is collected through the battery cell collection system, and the energy storage management system sends preset operating parameters to the sub-power module. The sub-power module collects the three-phase voltage and current data of the corresponding battery cell and the bus voltage data of the power station grid connection point, and generates adjustment parameters according to the three-phase voltage and current data, bus voltage data, preset operating parameters, and battery cell charge state. Active control instructions and reactive control instructions are generated based on the adjustment parameters. The energy storage management system performs comprehensive control according to the active control instructions and reactive control instructions, thereby improving the control accuracy and control efficiency of the energy storage system.

[0030] By obtaining the adjusted active power according to the preset active power and the target frequency difference, and obtaining the adjusted reactive power according to the preset reactive power and the target voltage difference, the reference three-phase voltage and current and the reference reactive power are obtained according to the adjusted active power and the adjusted reactive power, that is, the adjustment parameters, thereby improving the adjustment accuracy.

[0031] By collecting the AC frequency of the battery cell and determining the target frequency difference based on the frequency difference between the AC frequency of the battery cell and the preset frequency, and collecting the AC voltage of the battery cell and determining the target voltage difference based on the voltage difference between the AC voltage of the battery cell and the preset voltage, the reliability of regulating active power and regulating reactive power is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 A schematic diagram of the connection between a grid-connected distributed energy storage system and a power station grid connection point provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] like Figure 1 As shown, an embodiment of the present invention provides a grid-type distributed energy storage system, including: a battery module, a grid-type power module and an energy storage management system.

[0036] Specifically, the battery module is electrically connected to the grid-type power module, the grid-type power module is electrically connected to the power station grid connection point through the substation transformer, and the energy storage management system is electrically or communicatively connected to the battery module and the grid-type power module respectively.

[0037] The battery module includes a plurality of battery cells connected in series and a corresponding plurality of battery cell collection systems, and the networked power module includes a plurality of sub-power modules corresponding to the battery cells.

[0038] Specifically, the plurality of battery cells connected in series are electrically connected to the corresponding plurality of battery cell collection systems, the plurality of battery cells connected in series are also electrically connected to the corresponding sub-power modules, the sub-power modules are electrically connected to the power station grid connection point through the substation transformer, and the energy storage management system is electrically or communicatively connected to the battery cell collection system and the sub-power modules respectively.

[0039] The battery cell collection system is used to collect the charge state of the battery cells.

[0040] The energy storage management system is used to send preset operating parameters to the sub-power module.

[0041] The sub-power module is also used to collect the three-phase voltage and current data of the corresponding battery cell and the bus voltage data of the power station grid connection point, generate adjustment parameters according to the three-phase voltage and current data, the bus voltage data, the preset operating parameters, and the battery cell charge state, and generate active control instructions and reactive control instructions based on the adjustment parameters.

[0042] The energy storage management system is also used to perform comprehensive control according to the active power control instruction and the reactive power control instruction.

[0043] Specifically, the number of battery cells and battery cell collection systems in the battery module is the same as the number of sub-power modules and is at least 2.

[0044] In this embodiment, the sub-power module includes an energy storage PCS and a PCS controller. The DC end of the energy storage PCS is electrically connected to the corresponding battery cell, and the AC end is electrically connected to the power station grid point through the station area transformer. The energy storage PCS is used to convert the DC output of the battery cell into three-phase AC power and collect three-phase voltage and current data. The PCS controller is used for the bus voltage data of the power station grid point, generates adjustment parameters according to the three-phase voltage and current data, bus voltage data, preset operating parameters, and battery cell charge state, and generates active control instructions and reactive control instructions based on the adjustment parameters.

[0045] Exemplarily, the sub-power module is further used to obtain a bus voltage deviation according to the bus voltage data and a preset bus voltage reference value.

[0046] The sub-power module is also used to generate an adjustment parameter when the bus voltage deviation is greater than a preset bus voltage deviation threshold, and to generate an active control instruction and a reactive control instruction based on the adjustment parameter.

[0047] The adjustment parameters include: reference three-phase voltage and current and reference reactive power.

[0048] Specifically, the bus voltage deviation is the difference between the bus voltage data and the preset bus voltage reference value. When the bus voltage deviation is greater than the preset bus voltage deviation threshold, the sub-power module generates an adjustment parameter and generates an active control instruction and a reactive control instruction based on the adjustment parameter.

[0049] Exemplarily, the sub-power module is further used to generate a voltage phase control instruction value, namely, the active power control instruction, according to the state of charge of the battery cell, the three-phase voltage and current data and the reference three-phase voltage and current.

[0050] The sub-power module is further used to generate a voltage amplitude control instruction value, namely, the reactive power control instruction, according to the bus voltage deviation and the reference reactive power.

[0051] The energy storage management system is also used to generate an internal potential control command value according to the voltage phase control command value and the voltage amplitude control command value, and perform internal potential control.

[0052] Exemplarily, the preset operating parameters include: preset active power, preset reactive power, target frequency difference and target voltage difference.

[0053] The sub-power module is further used to obtain the adjusted active power according to the preset active power and the target frequency difference, and to obtain the adjusted reactive power according to the preset reactive power and the target voltage difference.

[0054] The sub-power module is also used to obtain the reference three-phase voltage and current and the reference reactive power, that is, the adjustment parameters, according to the adjusted active power and the adjusted reactive power.

[0055] Exemplarily, the preset operating parameters also include: a preset frequency.

[0056] The energy storage management system is also used to collect the battery cell AC frequency, and determine the target frequency difference according to the frequency difference between the battery cell AC frequency and the preset frequency.

[0057] Specifically, the target frequency difference is obtained based on a frequency modulation, including: collecting the battery cell AC frequency, obtaining the frequency difference between the battery cell AC frequency and the preset frequency, comparing the frequency difference with a preset first judgment range, when the frequency difference is within the first judgment range, the target frequency difference is 0, when the frequency difference is not within the first judgment range, the target frequency difference is the frequency difference.

[0058] Exemplarily, the preset operating parameters also include: a preset voltage.

[0059] The energy storage management system is also used to collect the battery cell AC voltage and determine the target voltage difference according to the voltage difference between the battery cell AC voltage and the preset voltage.

[0060] Specifically, the target voltage difference is obtained based on a primary voltage regulation, including: collecting the battery cell AC voltage, obtaining the voltage difference between the battery cell AC voltage and a preset voltage, comparing the voltage difference with a preset second judgment range, when the voltage difference is within the second judgment range, the target voltage difference is 0, when the voltage difference is not within the second judgment range, the target voltage difference is the voltage difference.

[0061] Exemplarily, the energy storage management system is further used to generate an active power correction factor according to the state of charge of the battery cell and the rated capacity of the battery cell.

[0062] The energy storage management system is also used to construct a grid-type energy storage active power control model based on the traditional synchronous generator rotor motion equation, and set the active power correction coefficient in the grid-type energy storage active power control model.

[0063] Specifically, the grid-type energy storage active power control model is used to execute the active power control instruction.

[0064] Exemplarily, the energy storage management system is also used to construct a reactive voltage droop control link and establish a grid-type energy storage reactive power control model based on the voltage regulation characteristics of a traditional synchronous generator.

[0065] Specifically, the grid-type energy storage reactive power control model is used to execute the reactive power control instruction.

[0066] Exemplarily, the energy storage management system is also used to construct a voltage outer-loop proportional-integral control link and a current inner-loop proportional-integral control link according to a preset proportional-integral control strategy, and to establish a grid-type energy storage comprehensive control model based on the voltage outer-loop proportional-integral control link and the current inner-loop proportional-integral control link.

[0067] Specifically, the grid-type energy storage comprehensive control model is used to perform internal potential control, namely, voltage outer loop proportional integral control and current inner loop proportional integral control.

[0068] The embodiment of the present invention collects the state of charge of the battery cell through the battery cell collection system, and the energy storage management system sends preset operating parameters to the sub-power module. The sub-power module collects the three-phase voltage and current data of the corresponding battery cell and the bus voltage data of the power station grid connection point, generates adjustment parameters according to the three-phase voltage and current data, the bus voltage data, the preset operating parameters, and the state of charge of the battery cell, and generates active control instructions and reactive control instructions based on the adjustment parameters. The energy storage management system performs comprehensive control according to the active control instructions and the reactive control instructions, thereby improving the control accuracy and control efficiency of the energy storage system.

[0069] By obtaining the adjusted active power according to the preset active power and the target frequency difference, and obtaining the adjusted reactive power according to the preset reactive power and the target voltage difference, the reference three-phase voltage and current and the reference reactive power are obtained according to the adjusted active power and the adjusted reactive power, that is, the adjustment parameters, thereby improving the adjustment accuracy.

[0070] By collecting the AC frequency of the battery cell and determining the target frequency difference based on the frequency difference between the AC frequency of the battery cell and the preset frequency, and collecting the AC voltage of the battery cell and determining the target voltage difference based on the voltage difference between the AC voltage of the battery cell and the preset voltage, the reliability of regulating active power and regulating reactive power is improved.

[0071] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0072] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A grid-type distributed energy storage system, characterized in that: include: Battery modules, grid-connected power modules and energy storage management systems; The battery module includes a plurality of battery cells connected in series and a corresponding plurality of battery cell collection systems, and the networked power module includes a plurality of sub-power modules corresponding to the battery cells; The battery cell collection system is used to collect the battery cell charge state; The energy storage management system is used to send preset operating parameters to the sub-power module; The sub-power module is also used to collect three-phase voltage and current data of the corresponding battery cell and bus voltage data of the power station grid connection point, generate adjustment parameters according to the three-phase voltage and current data, the bus voltage data, the preset operating parameters, and the battery cell charge state, and generate active control instructions and reactive control instructions based on the adjustment parameters; The energy storage management system is also used to perform comprehensive control according to the active power control instruction and the reactive power control instruction.

2. A grid-type distributed energy storage system according to claim 1, characterized in that: The sub-power module is also used to obtain a bus voltage deviation according to the bus voltage data and a preset bus voltage reference value; The sub-power module is also used to generate an adjustment parameter when the bus voltage deviation is greater than a preset bus voltage deviation threshold, and generate an active control instruction and a reactive control instruction based on the adjustment parameter; The adjustment parameters include: reference three-phase voltage and current and reference reactive power.

3. A grid-type distributed energy storage system according to claim 2, characterized in that: The sub-power module is also used to generate a voltage phase control instruction value, that is, the active power control instruction, according to the state of charge of the battery cell, the three-phase voltage and current data and the reference three-phase voltage and current; The sub-power module is also used to generate a voltage amplitude control instruction value, that is, the reactive power control instruction, according to the bus voltage deviation and the reference reactive power; The energy storage management system is also used to generate an internal potential control command value according to the voltage phase control command value and the voltage amplitude control command value, and perform internal potential control.

4. A grid-type distributed energy storage system according to claim 2, characterized in that: The preset operating parameters include: preset active power, preset reactive power, target frequency difference and target voltage difference; The sub-power module is further used to obtain the adjusted active power according to the preset active power and the target frequency difference, and to obtain the adjusted reactive power according to the preset reactive power and the target voltage difference; The sub-power module is also used to obtain the reference three-phase voltage and current and the reference reactive power, that is, the adjustment parameters, according to the adjusted active power and the adjusted reactive power.

5. A grid-type distributed energy storage system according to claim 4, characterized in that: The preset operating parameters also include: a preset frequency; The energy storage management system is also used to collect the battery cell AC frequency, and determine the target frequency difference according to the frequency difference between the battery cell AC frequency and the preset frequency.

6. A grid-type distributed energy storage system according to claim 4, characterized in that: The preset operating parameters also include: preset voltage; The energy storage management system is also used to collect the battery cell AC voltage and determine the target voltage difference according to the voltage difference between the battery cell AC voltage and the preset voltage.

7. A grid-type distributed energy storage system according to claim 1, characterized in that: The energy storage management system is also used to generate an active power correction coefficient according to the state of charge of the battery cell and the rated capacity of the battery cell; The energy storage management system is also used to construct a grid-type energy storage active power control model based on the traditional synchronous generator rotor motion equation, and set the active power correction coefficient in the grid-type energy storage active power control model.

8. A grid-type distributed energy storage system according to claim 1, characterized in that: The energy storage management system is also used to construct a reactive voltage droop control link and establish a grid-type energy storage reactive power control model according to the voltage regulation characteristics of a traditional synchronous generator.

9. A grid-type distributed energy storage system according to claim 1, characterized in that: The energy storage management system is also used to construct a voltage outer loop proportional integral control link and a current inner loop proportional integral control link according to a preset proportional integral control strategy, and to establish a grid-type energy storage comprehensive control model based on the voltage outer loop proportional integral control link and the current inner loop proportional integral control link.

Images