Active control method and system for energy storage power station combining inertia and droop characteristics and medium

Abstract

The invention discloses an energy storage power station active control method combining inertia and droop characteristics. The method comprises the following steps: establishing a mathematical model of an inverter circuit in an energy storage power station according to an electromagnetic characteristic equation of a synchronous generator; calculating the output power of the energy storage power station according to the mathematical model; calculating the output power according to the droop characteristic to obtain a voltage reference value of the output voltage of the inverter circuit; calculating a voltage difference value, and calculating a grid-connected current reference value according to the voltage difference value; and obtaining a reference modulation voltage wave according to the grid-connected current actual value and the grid-connected current reference value, wherein the reference modulation voltage wave is used for modulating the voltage wave of the energy storage power station to realize the balance of the three-phase grid-connected current. According to the method, by simulating a characteristic equation of a synchronous generator, establishing a mathematical model of an energy storage converter and designing active and reactive control outer rings and a voltage and current control inner ring, an energy storage power station can realize self-synchronization grid connection while having external characteristics of a voltage source, and voltage and frequency support is provided for a power grid when necessary.

Description

Technical Field

[0001] This invention relates to the field of power system technology, specifically to an active control method, system, equipment, and medium for an energy storage power station that combines inertia and droop characteristics. Background Technology

[0002] With the escalating energy crisis, various new energy sources, such as wind power, solar power, and fuel cell power generation systems, are being widely adopted. In high-power wind power systems, energy storage converters are a crucial component for achieving power feedback to the grid, and the control performance of the converter's grid-side current directly determines the system's performance. The control strategy of the energy storage converter is key to grid-connected control; all grid-connected power generation systems, regardless of the type of new energy source, must have a grid-side DC-AC conversion unit. Active and reactive power control of the grid-connected inverter can be achieved by controlling the output current vector of the energy storage converter. The grid-connected control method is actually indirectly controlling the output current vector through the AC-side voltage vector of the energy storage converter, hence the name indirect current control. This indirect current control method requires no current detection and is simple to control; however, it is highly sensitive to changes in system parameters. Because it is based on the system's steady-state model, its dynamic response is slow, and the lack of current feedback control makes it difficult to guarantee the waveform quality of the energy storage converter's output current. Due to the shortcomings of indirect current control, the existing technology adopts a direct current control scheme. By controlling the amplitude of the output current vector of the energy storage converter and its phase relative to the grid voltage vector, the active and reactive currents of the energy storage converter can be controlled, thereby realizing the control of the energy storage converter.

[0003] In grid-connected systems, the total harmonic distortion rate of the grid-connected current of the energy storage converter is required to be sufficiently small. Therefore, the output filtering of the energy storage converter is particularly important. In the existing technology, there are resonance peaks in the amplitude-frequency characteristics of the output filter of the energy storage converter, which reduces the control stability of the energy storage converter and causes the energy storage converter to oscillate. Summary of the Invention

[0004] The purpose of this invention is to provide an active control method, system, device, and medium for energy storage power stations that combines inertia and droop characteristics, thereby solving the technical problems existing in the prior art.

[0005] This invention is achieved through the following technical solution: In a first aspect, the first embodiment of the present invention provides an active control method for an energy storage power station that combines inertia and droop characteristics, comprising: A mathematical model of the inverter circuit in the energy storage power station is established based on the electromagnetic characteristic equation of the synchronous generator. The output power of the energy storage power station is calculated based on the mathematical model, and the output power includes active power and reactive power. The output power is calculated based on the droop characteristic to obtain the voltage reference value of the inverter circuit output voltage; Calculate the voltage difference based on the voltage reference value and the voltage value at the grid connection point, and calculate the grid connection current reference value based on the voltage difference; A reference modulated voltage wave is obtained based on the actual value of the grid-connected current and the calculated reference value of the grid-connected current. The reference modulated voltage wave is used to modulate the voltage wave of the energy storage power station to achieve the balance of the three-phase grid-connected current.

[0006] Furthermore, the mathematical model is as follows: ; in, This refers to the voltage on the bridge arm side of the inverter. Where L is the output voltage of the inverter, and L is the reactance. R is the output current of the inverter, and R is the internal resistance.

[0007] Furthermore, the formula for calculating the output power of the energy storage power station based on the mathematical model is as follows: ; Where P represents the active power of the energy storage power station, and Q represents the reactive power of the energy storage power station. , , These are the corresponding electric potentials , , phase voltage, , , These are the corresponding electric potentials , , The phase current.

[0008] Furthermore, the step of calculating the output power based on the droop characteristic to obtain the voltage reference value of the inverter circuit output voltage specifically includes: Based on the droop characteristic, the first command value of the output voltage phase angle is obtained through the active power. The phase angle of the output voltage is then adjusted in reverse using the first command value to obtain the phase angle of the reference voltage. The second command value of the output voltage amplitude is obtained by using the reactive power based on the droop characteristic, and the amplitude of the reference voltage is obtained by using the second command value to adjust the amplitude of the output voltage in reverse. The voltage reference value of the inverter circuit output voltage is obtained based on the phase angle and amplitude of the reference voltage.

[0009] Furthermore, the formula for calculating the voltage reference value of the inverter circuit output voltage based on the phase angle and amplitude of the reference voltage is as follows: ; ; in, The magnitude of the synthesized potential. This is the no-load potential. This is the voltage regulation coefficient. This is the reactive power regulation coefficient. This is a reference value for reactive power. This is the reactive power output value. The phase angle, This is the voltage reference value. This is the voltage output value.

[0010] Further, the voltage difference is calculated based on the voltage reference value and the voltage value at the grid connection point, and the grid connection current reference value is calculated based on the voltage difference, specifically including: The voltage feedback value of the inverter circuit is used as the voltage value at the grid connection point; Calculate the voltage difference between the voltage reference value and the voltage feedback value; The grid-connected current reference value is calculated using the voltage difference and virtual impedance.

[0011] Furthermore, the step of obtaining the reference modulation voltage wave based on the actual value of the grid-connected current and the calculated reference value of the grid-connected current specifically includes: Calculate the current difference between the reference value and the actual value of the grid-connected current; A reference modulation voltage wave is obtained using a quasi-PR regulator based on the current difference.

[0012] Secondly, another embodiment of the present invention provides an active control system for an energy storage power station that combines inertia and droop characteristics, used in the method described in the first embodiment above, the system comprising: The model building module is used to build a mathematical model of the inverter circuit in the energy storage power station based on the electromagnetic characteristic equations of the synchronous generator. The first calculation module is used to calculate the output power of the energy storage power station according to the mathematical model, wherein the output power includes active power and reactive power. The second calculation module is used to calculate the output power based on the droop characteristics and obtain the voltage reference value of the inverter circuit output voltage. The third calculation module is used to calculate the voltage difference based on the voltage reference value and the voltage value at the grid connection point, and to calculate the grid connection current reference value based on the voltage difference; The modulation module is used to obtain a reference modulation voltage wave based on the actual value of the grid-connected current and the calculated reference value of the grid-connected current. The reference modulation voltage wave is used to modulate the voltage wave of the energy storage power station to achieve the balance of the three-phase grid-connected current.

[0013] Thirdly, another embodiment of the present invention provides an electronic device comprising: a processor, an input device, an output device, and a memory, wherein the processor, the input device, the output device, and the memory are interconnected, the memory is used to store a computer program, the computer program includes program instructions, and the processor is configured to invoke the program instructions to execute the method described in the first embodiment above.

[0014] Fourthly, another embodiment of the present invention provides a computer-readable storage medium storing a computer program, the computer program including program instructions that, when executed by a processor, cause the processor to perform the method described in the first embodiment above.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0016] This invention provides an active control method, system, terminal, and medium for an energy storage power station that combines inertial and droop characteristics. The active support control strategy for the energy storage power station combines inertial and droop control. By simulating the characteristic equations of a synchronous generator, a mathematical model of the energy storage converter is established. An outer loop of active and reactive power control and an inner loop of voltage and current control are designed, enabling the energy storage power station to achieve self-synchronization and grid connection while possessing external voltage source characteristics, and to provide voltage and frequency support to the grid when necessary. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 A flowchart illustrating an active control method for an energy storage power station that combines inertia and droop characteristics, provided in the first embodiment of the present invention; Figure 2 This is a schematic diagram of the energy storage converter in an embodiment of the present invention; Figure 3 A schematic diagram of the active support overall control structure for a self-synchronizing voltage source type energy storage power station; Figure 4 This is a schematic diagram of the structure of an active control system for an energy storage power station that combines inertia and droop characteristics, provided as another embodiment of the present invention. Detailed Implementation

[0018] To make the objectives, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. The described embodiments should not be regarded as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0021] In the following description, the terms "first" and "second" are used merely to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first" and "second" may be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0023] It should be noted that the grid voltage-oriented energy storage converter control can employ a dual-loop control structure consisting of a DC voltage outer loop and active and reactive current inner loops. The DC voltage outer loop aims to stabilize or regulate the DC voltage. Clearly, introducing DC-side voltage feedback and using a PI regulator achieves zero steady-state error control of the DC voltage. Since DC voltage control can be achieved through the control of 'aa', the output of the DC voltage outer loop PI regulator is the current reference value of the active current inner loop, thereby regulating the active power output of the energy storage converter. The reactive current inner loop's current reference value is obtained from the reactive power reference value to be supplied to the grid as needed. When this value is 0, the energy storage converter operates at unity power factor, meaning it only supplies active power to the grid. The current inner loop is controlled in the d-coordinate system; that is, the detected value of the energy storage converter's output current is converted into a DC value in the synchronously rotating dq coordinate system through a three-phase to two-phase, two-phase stationary to two-phase rotating coordinate transformation. The current reference value is compared with that of the inner current loop, and zero steady-state error control of ia and iq is achieved through corresponding PI regulators. The output signal of the inner current loop PI regulator, after undergoing a two-phase rotating-two-phase stationary inverse transformation, can be used to obtain the corresponding switching drive signal for the energy storage converter via SPWM or SVPWM. This enables grid-connected control of the energy storage converter. The energy storage converter in the energy storage power station of this application adopts a dual-loop control structure with a DC voltage outer loop and active and reactive current inner loops.

[0024] like Figure 1 The diagram shows a flowchart of an active control method for an energy storage power station that combines inertia and droop characteristics, provided in the first embodiment of the present invention. The method includes: S1. Establish a mathematical model of the inverter circuit in the energy storage power station based on the electromagnetic characteristic equation of the synchronous generator.

[0025] like Figure 2 The diagram shows the main circuit topology and control structure of the energy storage oscillator in the energy storage power station of this application. The DC voltage source is the output of the energy storage unit after passing through a DC / DC converter. When designing the active support control strategy, it can be considered as a constant DC voltage source Udc. S1~S6 are fully controlled power switches forming the three-phase bridge inverter circuit; in this embodiment, insulated-gate bipolar transistors (IGBTs) are used. The output side of the inverter circuit is connected to an LC filter circuit, consisting of filter inductors and capacitors on the bridge arm side, and is connected to the power grid or load via an AC contactor.

[0026] In this application, to achieve active support control of the energy storage power station, the inverter circuit needs to simulate the characteristic equations of a synchronous generator. This is because... Figure 2It can be observed that there is a one-to-one correspondence between the inverter circuit of the energy storage power station and the synchronous generator. If the voltage on the bridge arm side of the grid-connected inverter is regarded as the induced electromotive force of a synchronous generator, then the filter reactance at the output of the grid-connected inverter can be regarded as the synchronous reactance of a synchronous generator. Similarly, the output voltage of the grid-connected inverter after the filter circuit can be regarded as the terminal voltage of the synchronous generator. In this application, the inverter is a three-phase inverter.

[0027] Therefore, based on the electromagnetic characteristic equation of a synchronous generator, the mathematical model of the inverter circuit in an energy storage power station is obtained. The mathematical model is as follows: ; in, This refers to the voltage on the bridge arm side of the inverter. L is the output voltage of the inverter; L is the reactance. R is the output current of the inverter; R is the internal resistance.

[0028] S2 calculates the output power of the energy storage power station based on the mathematical model. The output power includes active power and reactive power.

[0029] like Figure 3 As shown, a schematic diagram of the overall active support control structure of a self-synchronizing voltage source type energy storage power station is presented.

[0030] Based on the inverter's output voltage and output current The active power P and reactive power Q output by the energy storage power station can be calculated using the following method: ; Where P is the active power of the energy storage power station; Q is the reactive power of the energy storage power station. , , These are the corresponding electric potentials , , Phase voltage; , , These are the corresponding electric potentials , , The phase current.

[0031] S3, calculate the output power based on the droop characteristic to obtain the voltage reference value of the inverter circuit output voltage.

[0032] It should be noted that droop control uses a frequency-first droop characteristic curve similar to that of a traditional generator as the control method for the inverter. That is, stable frequency and voltage are obtained through P / f droop control and QNV droop control respectively. This control method controls the active and reactive power output of the grid-connected inverter separately, without the need for communication coordination between units. It achieves the goals of plug-and-play micro-sources and peer control, ensuring power balance and frequency uniformity, and has the characteristics of simplicity and reliability.

[0033] In some embodiments, the output power is calculated based on the droop characteristic to obtain a voltage reference value for the inverter circuit output voltage, specifically including: Based on the droop characteristic, the first command value of the output voltage phase angle is obtained through the active power. The phase angle of the output voltage is then adjusted in reverse using the first command value to obtain the phase angle of the reference voltage. Based on the droop characteristic, the second command value of the output voltage amplitude is obtained through reactive power. The second command value is used to adjust the output voltage amplitude in reverse to obtain the reference voltage amplitude. Based on the phase angle and amplitude of the adjusted output reference voltage, the voltage reference value of the inverter circuit output voltage is obtained.

[0034] In this application, droop control controls the amplitude and power angle of the output voltage by controlling active and reactive power. Essentially, each inverter unit detects its own output power, obtains command values ​​for the output voltage frequency and amplitude through the droop characteristic, and then fine-tunes its output voltage amplitude and frequency in reverse to achieve a reasonable distribution of active and reactive power in the system.

[0035] It should be noted that the reactive power-voltage control actively supported by the energy storage power station in this application mainly simulates the characteristics of the synchronous generator excitation regulator. This characteristic is obtained from the reactive power-voltage droop characteristic equation, specifically: .

[0036] Based on the phase angle and amplitude of the reference voltage, the energy storage power station exhibits the characteristics of a voltage source. The reference value for the three-phase inverter output voltage can be obtained from the phase angle and amplitude of the reference voltage, as detailed below. ; in, This represents the magnitude of the synthesized potential. This is the no-load potential; This is the voltage regulation coefficient; This is the reactive power regulation coefficient; This is a reference value for reactive power; This is the reactive power output value; Phase angle; This is the voltage reference value; This is the voltage output value.

[0037] S4. Calculate the voltage difference based on the voltage reference value and the voltage value at the grid connection point, and then calculate the grid connection current reference value based on the voltage difference.

[0038] It is understood that the energy storage power station provided in this application has a two-layer control structure, in which the active power loop and reactive power loop are the outer control loops, and the voltage and current dual closed loops are the inner control loops. The phase angle of the reference voltage output by the active power outer loop and the amplitude of the reference voltage output by the reactive power outer loop are combined to form the voltage vector reference value of the energy storage converter.

[0039] In some embodiments, a voltage difference is obtained based on a voltage reference value and a voltage value at the grid connection point, and a grid connection current reference value is calculated based on the voltage difference, specifically including: The voltage feedback value of the inverter circuit is used as the voltage value at the grid connection point; Calculate the voltage difference between the voltage reference value and the voltage feedback value; The reference value of grid-connected current is calculated using the voltage difference and virtual impedance.

[0040] Understandably, in order to prevent interference between the outer control loop and the inner control loop, the frequency bands need to be staggered in this application.

[0041] A low system gain at the power frequency is detrimental to improving system control accuracy. To increase the gain at the power frequency, a proportional-resonant controller (PR controller) can be used as the controller for the inner current loop. The PR controller sets the system's resonant point at a specified frequency, thus theoretically allowing the system gain at the resonant point to reach infinity. However, since ideal PR control is difficult to achieve in practical control systems, a quasi-PR controller, which is easier to implement in engineering, can be chosen. The quasi-PR controller not only retains the advantages of the PR controller but also contributes to the stability of the control system. Its transfer function expression is: ; in, For transfer functions, The proportional coefficient of the regulator. The resonant coefficient of the regulator. For the transition frequency, Let s be the resonant frequency and s be the complex frequency. Since the purpose of setting the quasi-PR controller is to increase the system gain at the power frequency, the resonant frequency should be set to the power frequency, i.e., 314.16 rad / s. Among the above parameters, the proportional gain determines the gain across the entire frequency band, while the resonant coefficient and corner frequency have a more significant impact on the gain near the power frequency. Using the Bode plot of the quasi-PR controller with different parameters in MATLAB software toolbox, the following conclusions can be drawn: 1. The larger the resonant coefficient, the greater the gain at and near the resonant point, and the smaller the error of the control system after entering steady state. However, the impact of harmonics on the control system will also be amplified. 2. Changing the corner frequency does not change the gain at the resonant point. Therefore, the corner resonant frequency is not related to the error after the system enters steady state. However, as the corner frequency increases, the gain near the resonant point decays more and more slowly, thus increasing the system bandwidth and speeding up the response.

[0042] When the PR regulator is used as the controller of the inner current loop, the reference value of the outer voltage loop is the three-phase voltage value synthesized by the amplitude and phase angle as mentioned above, and the feedback value of the outer voltage loop is the voltage value at the grid connection point. The reference value of the three-phase grid-connected current can be calculated by subtracting the two values ​​and then passing through the virtual impedance link.

[0043] S5, based on the grid-connected current reference value and the actual grid-connected current value, obtains a reference modulation voltage wave. The reference modulation voltage wave is used to modulate the voltage wave of the energy storage voltage to achieve the balance of the three-phase grid-connected current.

[0044] In some embodiments, a reference modulated voltage wave is obtained based on a grid-connected current reference value and an actual grid-connected current value, including: Calculate the current difference between the reference value and the actual value of the grid-connected current; The reference modulated voltage wave is obtained using a quasi-PR regulator based on the current difference.

[0045] This application presents an active control method for energy storage power stations that combines inertia and droop characteristics. Based on a reference modulation voltage wave, it modulates the voltage wave of the energy storage power station using SPWM or SVPWM modulation. The purpose of this step is to reduce the steady-state error between the three-phase inverter output voltage and the reference voltage, thereby improving the robustness of the control system.

[0046] Specifically, the reference value is subtracted from the actual value of the three-phase grid-connected current, and then passed through the PR control loop to output the final reference modulation voltage wave. The modulation strategy can be SPWM modulation or SVPWM modulation.

[0047] The first embodiment of the present invention provides an active control method for energy storage power stations that combines inertia and droop characteristics. The active support control strategy for energy storage power stations combines inertial control and droop control. By simulating the characteristic equations of a synchronous generator, a mathematical model of the energy storage converter is established, and an outer loop of active and reactive power control and an inner loop of voltage and current control are designed. This enables the energy storage power station to achieve self-synchronization and grid connection while having the characteristics of a voltage source, and to provide voltage and frequency support to the grid when necessary.

[0048] like Figure 4 As shown, another embodiment of the present invention provides an active control system for an energy storage power station that combines inertia and droop characteristics, comprising: The model building module is used to build a mathematical model of the inverter circuit in the energy storage power station based on the electromagnetic characteristic equations of the synchronous generator. The first calculation module is used to calculate the output power of the energy storage power station based on a mathematical model. The output power includes active power and reactive power. The second calculation module is used to calculate the output power based on the droop characteristics and obtain the voltage reference value of the inverter circuit output voltage. The third calculation module is used to calculate the voltage difference based on the voltage reference value and the voltage value at the grid connection point, and to calculate the grid connection current reference value based on the voltage difference. The modulation module is used to obtain a reference modulation voltage wave based on the actual value of the grid-connected current and the calculated reference value of the grid-connected current. The reference modulation voltage wave is used to modulate the voltage wave of the energy storage power station to achieve the balance of the three-phase grid-connected current.

[0049] Another embodiment of the present invention provides an active control system for an energy storage power station that combines inertia and droop characteristics. The working principle is as follows: A model-building module establishes a mathematical model of the inverter circuit in the energy storage power station based on the electromagnetic characteristic equations of a synchronous generator; a first calculation module calculates the output power of the energy storage power station according to the mathematical model; the output power includes active power and reactive power; a second calculation module calculates the output power based on the droop characteristics to obtain a voltage reference value for the inverter circuit output voltage; a third calculation module obtains a voltage difference based on the voltage reference value and the voltage value at the grid connection point, and uses the voltage difference to calculate a grid-connected current reference value; a modulation module 4 obtains a reference modulation voltage wave based on the grid-connected current reference value and the actual grid-connected current value; the reference modulation voltage wave is used to modulate the voltage wave of the energy storage voltage to achieve balance of the three-phase grid-connected current.

[0050] The execution process of each module can be carried out according to the process flow of the active control method for energy storage power stations that combines inertia and droop characteristics provided in the first embodiment, and will not be described in detail in this embodiment.

[0051] The active control system for an energy storage power station that combines inertia and droop characteristics provided in this invention embodiment and the active control method for an energy storage power station that combines inertia and droop characteristics are based on the same inventive concept and have the same beneficial effects, and will not be described again here.

[0052] Another embodiment of the present invention provides an electronic device, which includes a processor, an input device, an output device, and a memory. The processor, the input device, the output device, and the memory are interconnected. The memory is used to store a computer program, which includes program instructions. The processor is configured to call the program instructions to execute the method described in the first embodiment above.

[0053] It should be understood that, in the embodiments of the present invention, the processor may be a Central Processing Unit (CPU), but it may also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0054] Input devices may include touchpads, microphones, etc., and output devices may include displays (LCDs, etc.), speakers, etc.

[0055] The memory may include read-only memory and random access memory, and provides instructions and data to the processor. A portion of the memory may also include non-volatile random access memory. For example, the memory may also store information about the device type.

[0056] In specific implementations, the processor, input device, and output device described in the embodiments of the present invention can execute the implementation of the method embodiments described in the embodiments of the present invention, or they can execute the implementation of the system embodiments described in the embodiments of the present invention, which will not be repeated here.

[0057] The present invention also provides an embodiment of a computer-readable storage medium storing a computer program, the computer program including program instructions, which, when executed by a processor, cause the processor to perform the method described in the first embodiment above.

[0058] The computer-readable storage medium can be an internal storage unit of the terminal described in the foregoing embodiments, such as the terminal's hard drive or memory. The computer-readable storage medium can also be an external storage device of the terminal, such as a plug-in hard drive, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the terminal. Furthermore, the computer-readable storage medium can include both internal storage units and external storage devices of the terminal. The computer-readable storage medium is used to store the computer program and other programs and data required by the terminal. The computer-readable storage medium can also be used to temporarily store data that has been output or will be output.

[0059] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0060] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the terminals and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0061] In the several embodiments provided in this application, it should be understood that the disclosed systems and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices or units, or may be electrical, mechanical or other forms of connection.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. An active control method for an energy storage power station that combines inertia and droop characteristics, characterized in that, include: A mathematical model of the inverter circuit in the energy storage power station is established based on the electromagnetic characteristic equation of the synchronous generator. The output power of the energy storage power station is calculated based on the mathematical model, and the output power includes active power and reactive power. The output power is calculated based on the droop characteristic to obtain the voltage reference value of the inverter circuit output voltage; Calculate the voltage difference based on the voltage reference value and the voltage value at the grid connection point, and calculate the grid connection current reference value based on the voltage difference; A reference modulated voltage wave is obtained based on the actual value of the grid-connected current and the calculated reference value of the grid-connected current. The reference modulated voltage wave is used to modulate the voltage wave of the energy storage power station to achieve the balance of the three-phase grid-connected current.

2. The method according to claim 1, characterized in that, The mathematical model is as follows: ； in, This refers to the voltage on the bridge arm side of the inverter. Where L is the output voltage of the inverter, and L is the reactance. R is the output current of the inverter, and R is the internal resistance.

3. The method according to claim 2, characterized in that, The formula for calculating the output power of the energy storage power station based on the mathematical model is as follows: ； Where P represents the active power of the energy storage power station, and Q represents the reactive power of the energy storage power station. , , These are the corresponding electric potentials , , phase voltage, , , These are the corresponding electric potentials , , The phase current.

4. The method according to claim 1, characterized in that, The calculation of output power based on droop characteristics to obtain a voltage reference value for the inverter circuit output voltage specifically includes: Based on the droop characteristic, the first command value of the output voltage phase angle is obtained through the active power. The phase angle of the output voltage is then adjusted in reverse using the first command value to obtain the phase angle of the reference voltage. The second command value of the output voltage amplitude is obtained by using the reactive power based on the droop characteristic, and the amplitude of the reference voltage is obtained by using the second command value to adjust the amplitude of the output voltage in reverse. The voltage reference value of the inverter circuit output voltage is obtained based on the phase angle and amplitude of the reference voltage.

5. The method according to claim 4, characterized in that, The formula for calculating the voltage reference value of the inverter circuit output voltage based on the phase angle and amplitude of the reference voltage is as follows: ； ； in, The magnitude of the synthesized potential. This is the no-load potential. This is the voltage regulation coefficient. This is the reactive power regulation coefficient. This is a reference value for reactive power. This is the reactive power output value. The phase angle, This is the voltage reference value. This is the voltage output value.

6. The method according to claim 5, characterized in that, The voltage difference is calculated based on the voltage reference value and the voltage value at the grid connection point, and the grid connection current reference value is calculated based on the voltage difference, specifically including: The voltage feedback value of the inverter circuit is used as the voltage value at the grid connection point; Calculate the voltage difference between the voltage reference value and the voltage feedback value; The grid-connected current reference value is calculated using the voltage difference and virtual impedance.

7. The method according to claim 6, characterized in that, The specific steps for obtaining the reference modulation voltage wave based on the actual value of the grid-connected current and the calculated reference value of the grid-connected current include: Calculate the current difference between the reference value and the actual value of the grid-connected current; A reference modulation voltage wave is obtained using a quasi-PR regulator based on the current difference.

8. An active control system for an energy storage power station that combines inertia and droop characteristics, characterized in that, The system for implementing the method as described in any one of claims 1-7 includes: The model building module is used to build a mathematical model of the inverter circuit in the energy storage power station based on the electromagnetic characteristic equations of the synchronous generator. The first calculation module is used to calculate the output power of the energy storage power station according to the mathematical model, wherein the output power includes active power and reactive power. The second calculation module is used to calculate the output power based on the droop characteristics and obtain the voltage reference value of the inverter circuit output voltage. The third calculation module is used to calculate the voltage difference based on the voltage reference value and the voltage value at the grid connection point, and to calculate the grid connection current reference value based on the voltage difference; The modulation module is used to obtain a reference modulation voltage wave based on the actual value of the grid-connected current and the calculated reference value of the grid-connected current. The reference modulation voltage wave is used to modulate the voltage wave of the energy storage power station to achieve the balance of the three-phase grid-connected current.

9. An electronic device, comprising: The processor, input device, output device, and memory are interconnected, the memory being used to store a computer program, the computer program including program instructions, characterized in that the processor is configured to invoke the program instructions to perform the method as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, the computer program including program instructions that, when executed by a processor, cause the processor to perform the method as described in any one of claims 1-7.

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