Wide short-circuit ratio control method, device and equipment for full-power pumped storage unit and medium

Abstract

The invention relates to the technical field of energy storage unit control, and discloses a method, a device and equipment for controlling the wide short-circuit ratio of a full-power pumped storage unit, and a medium. The method comprises the following steps of: controlling a grid-side converter by using a wide short-circuit ratio network construction type control strategy; wherein the control strategy of the wide short-circuit ratio network construction type comprises the following steps: tracking a reference voltage obtained according to a first output voltage output by a network-side current inner loop and a network-side three-phase current transmitted by a network-side converter by using a voltage and current double closed-loop control strategy, and obtaining a second output voltage of a network-side current loop; generating a first switching signal according to grid-side phase information of operation of the grid-side converter and the second output voltage so as to drive the grid-side converter; acquiring voltages at two ends of the direct-current capacitor to obtain a capacitor voltage actual value; and generating a second switching signal according to the capacitor voltage actual value and the capacitor voltage reference value so as to drive the machine-side converter. Therefore, the stability of the full-power pumped storage unit is improved.

Description

Technical Field

[0001] This invention relates to the field of energy storage unit control technology, specifically to a wide short-circuit ratio control method, device, equipment, and medium for a full-power pumped-storage unit. Background Technology

[0002] Currently, full-power pumped-storage units, especially full-power variable-speed pumped-storage units, have significant research value in rapidly mitigating wind and solar power fluctuations. With the continuous expansion of new energy grid integration, their role in improving grid stability is also significant. Current control strategies for full-power variable-speed pumped-storage units mainly focus on grid-following control of DC voltage via an outer loop for the grid-side converter, and power control via an outer loop for the generator-side converter. The grid-side converter obtains grid-side phase information through a phase-locked loop. Grid-based control can actively support the grid's frequency and voltage, further leveraging the rapid adjustment capabilities of full-power variable-speed pumped-storage power stations in mitigating wind and solar power fluctuations.

[0003] In existing technologies, traditional grid-based control employs droop control, which uses a voltage loop to feed back the voltage at the point of common coupling (PCC) in the actual circuit. This causes the grid-side converter using droop control to be treated as an equivalent voltage source, leading to subsynchronous oscillations and instability when connected in parallel with a high-voltage grid. Although droop control offers high precision, its stability is poor in high-voltage grids.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The technical problem to be solved by this invention is how to improve the control stability of a full-power pumped-storage unit. The purpose is to provide a wide short-circuit ratio control method, device, equipment, and medium for a full-power pumped-storage unit to improve the control stability of the full-power pumped-storage unit.

[0006] This invention is achieved through the following technical solution:

[0007] In a first aspect, a wide short-circuit ratio control method for a full-power pumped-storage unit is provided. The full-power pumped-storage unit includes a pump-turbine, a grid-side converter, a turbine-side converter, and a synchronous motor. A DC capacitor is connected in parallel between the grid-side converter and the turbine-side converter. The pump-turbine converts the potential energy of water into electrical energy through the grid-side converter, turbine-side converter, and synchronous motor to supply power to the grid. The method includes: controlling the grid-side converter using a preset wide short-circuit ratio grid-type control strategy. The wide short-circuit ratio grid-type control strategy includes: tracking a reference voltage based on a first output voltage using a preset voltage-current dual closed-loop control strategy to obtain a second output voltage of the grid-side current loop. The voltage-current dual closed-loop control strategy uses the grid-side voltage outer loop and the grid-side... The inner current loop performs voltage tracking; the reference voltage is obtained based on the first output voltage and the grid-side three-phase current supplied to the grid by the grid-side converter; the first output voltage is the voltage output by the grid-side inner current loop; a first switching signal is generated based on the grid-side phase information of the grid-side converter and the second output voltage to drive the grid-side converter; the grid-side phase information is obtained based on the first output voltage and the grid-side three-phase current supplied to the grid by the grid-side converter; the voltage across the DC capacitor is acquired to obtain the actual value of the capacitor voltage; a second switching signal is generated based on the actual value of the capacitor voltage and a preset capacitor voltage reference value to drive the generator-side converter.

[0008] In some embodiments, the reference voltage is obtained based on the first output voltage and the grid-side three-phase current supplied to the grid by the grid-side converter as follows: obtaining alternative grid-side phase information for the operation of the grid-side converter; performing current conversion on the grid-side three-phase current based on the alternative grid-side phase information to obtain a grid-side rotating DC current; obtaining the real-time reactive power transmitted by the grid-side converter based on the first output voltage and the grid-side rotating DC current; and obtaining the reference voltage based on the real-time reactive power.

[0009] In some embodiments, the grid-side phase information is obtained based on the first output voltage and the grid-side three-phase current supplied to the grid by the grid-side converter in the following manner: obtaining alternative grid-side phase information for the operation of the grid-side converter; performing current conversion on the grid-side three-phase current based on the alternative grid-side phase information to obtain a grid-side rotating DC current; obtaining the real-time active power transmitted by the grid-side converter based on the first output voltage and the selected DC current; and obtaining the grid-side phase information based on the real-time active power.

[0010] In some embodiments, generating a first switching signal based on the grid-side phase information of the grid-side converter and the second output voltage includes: performing voltage compensation on the second output voltage to obtain a grid-side compensation voltage; using the grid-side phase information to perform voltage conversion on the grid-side compensation voltage to obtain a grid-side three-phase control voltage; acquiring the voltage across the DC capacitor in real time to obtain a reference capacitor voltage; setting half of the reference capacitor voltage as a preset normalization parameter for the grid-side generation modulation wave module; and inputting the grid-side three-phase control voltage into the grid-side generation modulation wave module to generate the first switching signal.

[0011] In some embodiments, generating a second switching signal based on the actual value of the capacitor voltage and a preset reference value of the capacitor voltage includes: acquiring the three-phase current on the machine side; performing current conversion on the three-phase current on the machine side to obtain a rotating DC current on the machine side; and generating the second switching signal based on the actual value of the capacitor voltage, the reference value of the capacitor voltage, and the rotating DC current on the machine side.

[0012] In some embodiments, the machine-side rotating DC current includes a machine-side direct-axis DC current and a machine-side quadrature-axis DC current; generating the second switching signal based on the actual value of the capacitor voltage, the reference value of the capacitor voltage, and the machine-side rotating DC current includes: inputting the voltage difference between the reference value of the capacitor voltage and the actual value of the capacitor voltage into a preset first machine-side proportional-integral control module to obtain a machine-side direct-axis reference current; obtaining a first difference between the machine-side direct-axis reference current and the machine-side direct-axis DC current; obtaining a second difference between a preset machine-side quadrature-axis reference current and the machine-side quadrature-axis DC current; and generating the second switching signal based on the first difference and the second difference.

[0013] Secondly, a wide short-circuit ratio control device for a full-power pumped-storage unit, the full-power pumped-storage unit including a pump-turbine, a grid-side converter, a turbine-side converter, and a synchronous motor; a DC capacitor is connected in parallel between the grid-side converter and the turbine-side converter; the pump-turbine converts the potential energy of water into electrical energy through the grid-side converter, the turbine-side converter, and the synchronous motor to supply power to the grid; the device includes a control module configured to control the grid-side converter using a preset wide short-circuit ratio grid-type control strategy; the wide short-circuit ratio grid-type control strategy includes: tracking a reference voltage based on a first output voltage using a preset voltage-current dual closed-loop control strategy to obtain a second output voltage of the grid-side current loop; the voltage-current dual closed-loop control strategy uses the outer grid-side voltage loop and the inner grid-side current loop to... Voltage tracking is implemented; the reference voltage is obtained based on the first output voltage and the grid-side three-phase current supplied to the grid by the grid-side converter; the first output voltage is the voltage output by the inner loop of the grid-side current; a first switching signal is generated based on the grid-side phase information of the grid-side converter and the second output voltage, so as to drive the grid-side converter using the first switching signal; the grid-side phase information is obtained based on the first output voltage and the grid-side three-phase current supplied to the grid by the grid-side converter; an acquisition module is configured to acquire the voltage across the DC capacitor to obtain the actual value of the capacitor voltage; a generation module is configured to generate a second switching signal based on the actual value of the capacitor voltage and a preset capacitor voltage reference value, so as to drive the generator-side converter using the second switching signal.

[0014] Thirdly, a wide short-circuit ratio control device for a full-power pumped-storage unit includes a processor and a memory storing program instructions, wherein the processor is configured to execute the above-described wide short-circuit ratio control method for a full-power pumped-storage unit when running the program instructions.

[0015] Fourthly, an electronic device comprising the aforementioned wide short-circuit ratio control device for full-power pumped storage units.

[0016] Fifthly, a storage medium stores program instructions that, when executed, perform the aforementioned wide short-circuit ratio control method for full-power pumped-storage units.

[0017] Compared with existing technologies, this invention controls the grid-side converter using a preset wide short-circuit ratio grid-type control strategy. Specifically, it tracks a reference voltage using a preset voltage-current dual closed-loop control strategy based on a first output voltage to obtain a second output voltage of the grid-side current loop. The reference voltage is obtained by combining the first output voltage from the grid-side current inner loop with the grid-side three-phase current supplied by the grid-side converter to the grid. Then, a first switching signal is generated based on the grid-side phase information of the grid-side converter and the second output voltage to drive the grid-side converter. Furthermore, the voltage across the DC capacitor is acquired to obtain the actual capacitor voltage value, and a second switching signal is generated based on the actual capacitor voltage value and a preset capacitor voltage reference value to drive the machine-side converter. Compared to existing technologies, this solution uses the first output voltage of the grid-side current inner loop to replace the voltage at the PCC point in the actual circuit for voltage feedback. The grid-side converter using droop control will not be equivalent to a voltage source, reducing the occurrence of subsynchronous oscillations that could lead to instability when connected in parallel with a strong grid, thereby improving the control stability of the full-power pumped storage unit. Attached Figure Description

[0018] 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:

[0019] Figure 1 This is a schematic diagram of a full-power pumped storage unit provided in an embodiment of this disclosure;

[0020] Figure 2 This is a circuit topology diagram of a grid-side converter provided in an embodiment of this disclosure;

[0021] Figure 3 This is a control block diagram of a wide short-circuit ratio network structure provided in an embodiment of this disclosure;

[0022] Figure 4 This is a flowchart of a wide short-circuit ratio control method for a full-power pumped-storage unit provided in an embodiment of this disclosure;

[0023] Figure 5 This is a control block diagram provided in this disclosure, which shows how a reference voltage is tracked based on a first output voltage using a preset voltage-current dual closed-loop control strategy to obtain the second output voltage of the grid-side current loop.

[0024] Figure 6 This is a flowchart of another full-power pumped-storage unit wide short-circuit ratio control method provided in this disclosure embodiment;

[0025] Figure 7 This is a flowchart of a wide short-circuit ratio control process for a full-power pumped storage unit provided in an embodiment of this disclosure.

[0026] Figure 8 This is a current simulation diagram of a grid-side converter with conventional grid-type control and wide short-circuit ratio grid-type control under a strong power grid with a short-circuit ratio of 21.6, provided in an embodiment of this disclosure.

[0027] Figure 9 This is a schematic diagram of a wide short-circuit ratio control device for a full-power pumped storage unit provided in an embodiment of this disclosure;

[0028] Figure 10 This is a schematic diagram of another full-power pumped storage unit wide short-circuit ratio control device provided in an embodiment of this disclosure. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0030] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0031] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0032] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0033] In this application, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0034] Please see Figure 1 , Figure 1 This is a schematic diagram of the full-power pumped storage unit of this application.

[0035] like Figure 1 As shown, a full-power pumped storage unit can be a full-power variable speed pumped storage unit.

[0036] Specifically, the full-power pumped storage unit 100 includes a pump turbine 101, a grid-side converter 102, a turbine-side converter 103, a DC capacitor 104, and a synchronous motor 105.

[0037] It should be noted that the pump-turbine 101 is the mechanical system in the full-power pumped-storage unit 100, and it is the core of energy conversion. It can convert the potential energy of the water in the upper reservoir into the mechanical energy of the turbine to drive the synchronous motor to generate electricity.

[0038] The grid-side converter 102, the generator-side converter 103, the DC capacitor 104, and the synchronous motor 105 together constitute the electrical system of the full-power pumped-storage unit 100.

[0039] Specifically, the synchronous motor 105 can be the electromechanical energy conversion hub in the full-power pumped storage unit 100.

[0040] The synchronous motor 105 can act as a generator to convert the mechanical energy output by the water pump turbine 101 into electrical energy. The AC-DC conversion is achieved through the machine-side converter 103, and after being buffered by the DC capacitor 104, the output is sent to the grid-side converter 102 and connected to the power grid through a filter and a step-up transformer to provide electrical energy.

[0041] The generator-side converter 103 can be the core of motor-side power regulation in the full-power pumped-storage unit 100.

[0042] The grid-side converter 102 can serve as the grid-side energy interaction interface.

[0043] like Figure 2 As shown, Figure 2 This is the circuit topology diagram of the grid-side converter 102.

[0044] Figure 2 In the diagram, point N represents the neutral point. The arrow indicates the direction of the current.

[0045] like Figure 2As shown, the grid-side converter 102 converts AC power into AC power and connects it to the power grid through a three-phase bridge circuit.

[0046] Specifically, the input voltage of the grid-side converter 102 This is the voltage across DC capacitor 104, whose energy is provided by the machine-side converter.

[0047] A three-phase bridge circuit consists of six IGBTs (Insulated Gate Bipolar Transistors).

[0048] Specifically, it includes: the first IGBT201, the second IGBT202, the third IGBT203, the fourth IGBT204, the fifth IGBT205, and the sixth IGBT206.

[0049] In this circuit, the first IGBT201 and the second IGBT202 are the first arms of the three-phase bridge circuit, corresponding to phase a in the three phases; the third IGBT203 and the fourth IGBT204 are the second arms of the three-phase bridge circuit, corresponding to phase b in the three phases; and the fifth IGBT205 and the sixth IGBT206 are the third arms of the three-phase bridge circuit, corresponding to phase c in the three phases.

[0050] The output phase voltage at the midpoint of each bridge arm is connected to the step-up transformer and then to the power grid via a filter circuit consisting of a filter resistor and a filter inductor.

[0051] DC capacitor 104 is used for energy buffering and voltage stabilization between machine-side converter 103 and grid-side converter 102.

[0052] This solution can control the grid-side converter 102 through a wide short-circuit ratio grid configuration, thereby improving control stability and facilitating bidirectional energy conversion, grid stability support, and efficient operation.

[0053] In some embodiments, please refer to Figure 3 , Figure 3 This is a control block diagram for a wide short-circuit ratio network.

[0054] like Figure 3 As shown, this wide short-circuit ratio grid-type control block diagram simulates the external characteristics of a synchronous generator through the coordinated control of the current loop, voltage loop, and droop loop, achieving stable grid connection and autonomous voltage / frequency support under strong grid / high short-circuit ratio scenarios.

[0055] Among them, the drooping loop outputs through the current loop. Power calculations are performed to obtain the real-time active power P. Then, droop control is used to calculate the grid-side phase information of the grid-side converter. and output voltage amplitude information back, As the d-axis voltage reference value of the voltage loop, and the current loop output The deviation between the inputs and outputs is used as the input to the voltage loop. After passing through the proportional-integral module, the output of the voltage loop is... and actual current value The deviation between the input and output is used as the input to the current loop, and the output is obtained through a proportional-integral module. .

[0056] It should be noted that, For the proportional gain in the proportional-integral module of the current loop; This refers to the integral gain in the proportional-integral module within the current loop. Represents integral operations. For the proportional gain in the proportional-integral module of the voltage loop; This refers to the integral gain in the proportional-integral module within the voltage loop. Represents integral operations.

[0057] Wide short-circuit ratio grid-type control achieves efficient, stable, and autonomous operation of full-power variable-speed pumped-storage units in wide short-circuit ratio scenarios through the coordinated action of current loop, voltage loop, power calculation module, and droop loop. Its core lies in enhancing the system's robustness to grid impedance changes through parameter adaptation, virtual inertia simulation, and autonomous support mechanisms, thus supporting the new power system's requirements for high-proportion renewable energy grid integration and flexible peak shaving.

[0058] For details, please refer to Figure 4 , Figure 4 This is a flowchart illustrating a wide short-circuit ratio control method for a full-power pumped-storage unit, as shown in an exemplary embodiment of this application.

[0059] Combination Figure 4 As shown, embodiments of this disclosure provide a method for controlling Figure 1 The method for a full-power pumped-storage unit shown includes:

[0060] Step S401: Control the grid-side converter using a preset wide short-circuit ratio grid-type control strategy. The wide short-circuit ratio grid-type control strategy includes: tracking a reference voltage using a preset voltage-current dual closed-loop control strategy based on a first output voltage to obtain a second output voltage of the grid-side current loop; the voltage-current dual closed-loop control strategy performs voltage tracking through a grid-side voltage outer loop and a grid-side current inner loop; the reference voltage is obtained based on the first output voltage and the grid-side three-phase current supplied by the grid-side converter to the grid; the first output voltage is the voltage output by the grid-side current inner loop; a first switching signal is generated based on the grid-side phase information of the grid-side converter and the second output voltage to drive the grid-side converter; the grid-side phase information is obtained based on the first output voltage and the grid-side three-phase current supplied by the grid-side converter to the grid.

[0061] Step S402: Collect the voltage across the DC capacitor to obtain the actual value of the capacitor voltage.

[0062] Step S403: Generate a second switching signal based on the actual value of the capacitor voltage and the preset reference value of the capacitor voltage, so as to drive the machine-side converter using the second switching signal.

[0063] The full-power pumped-storage unit wide short-circuit ratio control method provided in this embodiment controls the grid-side converter using a preset wide short-circuit ratio grid configuration control strategy. Specifically, it tracks a reference voltage based on a first output voltage using a preset voltage-current dual closed-loop control strategy to obtain a second output voltage of the grid-side current loop. The reference voltage is obtained by using the first output voltage from the grid-side current inner loop and the grid-side three-phase current supplied by the grid-side converter to the grid. Then, a first switching signal is generated based on the grid-side phase information of the grid-side converter and the second output voltage to drive the grid-side converter. The voltage across the DC capacitor is then acquired to obtain the actual value of the capacitor voltage. A second switching signal is generated based on the actual value of the capacitor voltage and a preset capacitor voltage reference value to drive the generator-side converter. Compared to existing technologies, this solution uses the first output voltage of the grid-side current inner loop to replace the voltage at the PCC point in the actual circuit for voltage feedback. The grid-side converter using droop control will not be equivalent to a voltage source, reducing the occurrence of subsynchronous oscillations that could lead to instability when connected in parallel with a strong grid, thereby improving the control stability of the full-power pumped storage unit.

[0064] Meanwhile, this solution eliminates the need for voltage sensors to collect the voltage at the PCC point in the actual circuit, saving on voltage sensors and reducing costs during actual construction.

[0065] It should be noted that after the grid-side converter is driven by the first switching signal, the voltage across the DC capacitor will change. Therefore, it is necessary to re-acquire the voltage across the DC capacitor to obtain the actual value of the capacitor voltage.

[0066] Furthermore, in step S101, the reference voltage is obtained based on the first output voltage and the grid-side three-phase current supplied to the grid by the grid-side converter in the following manner: obtaining the alternative grid-side phase information of the grid-side converter; performing current conversion on the grid-side three-phase current based on the alternative grid-side phase information to obtain the grid-side rotating DC current; obtaining the real-time reactive power transmitted by the grid-side converter based on the first output voltage and the grid-side rotating DC current; and obtaining the reference voltage based on the real-time reactive power.

[0067] In this way, by acquiring the alternative grid-side phase information of the grid-side converter, and then performing current conversion on the grid-side three-phase current according to the alternative grid-side phase information to obtain the grid-side rotating DC current, the real-time reactive power transmitted by the grid-side converter is obtained according to the first output voltage and the grid-side rotating DC current, and the reference voltage is obtained according to the real-time reactive power, thus realizing the accurate calculation of the reference voltage. This allows the reference voltage to be tracked according to the first output voltage using a preset voltage and current dual closed-loop control strategy, thereby realizing wide short-circuit ratio grid-type control of the grid-side converter.

[0068] It should be noted that the alternative grid-side phase information for grid-side converter operation is the grid-side phase information obtained in the previous operation of the grid-side converter.

[0069] Grid-side three-phase current includes grid-side Corresponding phase current Net side Corresponding phase current and net side Corresponding phase current .

[0070] Furthermore, the grid-side three-phase current is converted according to the candidate grid-side phase information to obtain the grid-side rotating DC current, including: performing Park transformation on the grid-side three-phase current according to the candidate grid-side phase information to obtain the grid-side rotating DC current.

[0071] It should be noted that the Park transformation is currently the most commonly used coordinate transformation for analyzing the operation of synchronous motors. It projects the three-phase current onto the direct and quadrature axes, namely the d-axis and q-axis, which rotate with the rotor, thus achieving diagonalization of the stator inductance matrix.

[0072] The grid-side rotating DC current includes: grid-side direct-axis DC current and grid-side quadrature-axis DC current.

[0073] It should be noted that the first output voltage of the grid-side current inner loop includes the voltage command component in the dq rotating coordinate system, namely the first grid-side direct-axis output voltage and the first grid-side quadrature-axis output voltage.

[0074] Furthermore, the real-time active power and real-time reactive power transmitted by the grid-side converter are obtained based on the first output voltage and the grid-side rotating DC current, including: by calculating... This allows for the acquisition of real-time reactive power. Real-time reactive power; This is the direct-axis output voltage of the first grid side; This refers to the direct-axis DC current on the grid side. This is the cross-axis output voltage of the first grid side; This refers to the cross-axis DC current on the grid side. These are the preset transformation parameters.

[0075] It should be noted that the preset transformation parameters The type of Park transformation in this scheme determines the outcome. If all Park transformations in this scheme are constant power transformations, then... If all Park transformations in this scheme are constant amplitude transformations, then .

[0076] It should be noted that the calculated reactive power Q should be filtered by a filter device to reduce its fluctuations.

[0077] Furthermore, the reference voltage is obtained based on real-time active power and real-time reactive power, including: using preset droop control or virtual synchronous machine control. Taking droop control as an example, this scheme calculates... To obtain the reference voltage, Reference voltage; The preset voltage threshold can be set according to power grid specifications or dispatch instructions; for example, it can be the rated voltage. This is the preset reactive power coefficient; This is the preset reactive power reference value.

[0078] Thus, when the actual reactive power deviates from the reactive power reference value, the reactive power droop loop adjusts. This drives the converter output voltage to change, thereby adjusting the reactive power output and achieving reactive power deviation response.

[0079] It should be noted that droop control or virtual synchronous machine control are both commonly used network-type controls.

[0080] It should be noted that the second output voltage of the grid-side current loop, like the first output voltage, includes a voltage command component in the dq rotating coordinate system. The second output voltage of the grid-side current loop includes: a second grid-side direct-axis output voltage and a second grid-side quadrature-axis output voltage. The first output voltage is the second output voltage obtained previously.

[0081] Furthermore, such as Figure 5 As shown, Figure 5 The control block diagram is as follows: Based on the first output voltage, a preset voltage and current dual closed-loop control strategy is used to track the reference voltage and obtain the second output voltage of the grid-side current loop.

[0082] like Figure 5 As shown, the reference voltage is obtained in the outer loop of the grid-side voltage. The first grid-side voltage deviation is obtained between the first grid-side direct-axis output voltage and the first grid-side voltage. This first grid-side voltage deviation is input into a preset first grid-side PI (Proportional-Integral) module 501 to obtain a first grid-side current reference value. The second grid-side voltage deviation between the preset grid-side quadrature-axis voltage reference value and the first grid-side quadrature-axis output voltage is obtained; this second grid-side voltage deviation is input into a preset second grid-side PI module 502 to obtain a second grid-side current reference value.

[0083] In the inner loop of the grid-side current, obtain the first grid-side current reference value and the grid-side direct-axis DC current. The first grid-side current deviation is calculated; the first grid-side current deviation is input into the preset third grid-side PI module 503 to obtain the second grid-side direct-axis output voltage. Obtain the second grid-side current reference value and the grid-side quadrature-axis DC current. The second grid-side current deviation is calculated; the second grid-side current deviation is input into the preset fourth grid-side PI module 504 to obtain the second grid-side quadrature axis output voltage. .

[0084] Furthermore, the grid-side phase information is obtained based on the first output voltage and the grid-side three-phase current supplied to the grid by the grid-side converter in the following manner: acquiring the alternative grid-side phase information for the operation of the grid-side converter; performing current conversion on the grid-side three-phase current based on the alternative grid-side phase information to obtain the grid-side rotating DC current; acquiring the real-time active power transmitted by the grid-side converter based on the first output voltage and the selected DC current; and acquiring the grid-side phase information based on the real-time active power. In this way, by acquiring the alternative grid-side phase information for the operation of the grid-side converter, performing current conversion on the grid-side three-phase current based on the alternative grid-side phase information to obtain the grid-side rotating DC current, and then acquiring the real-time active power transmitted by the grid-side converter based on the first output voltage and the selected DC current; and acquiring the grid-side phase information based on the real-time active power, dynamic adjustment of the dynamic information is achieved, so as to generate a first switching signal based on the grid-side phase information, thereby realizing precise and stable control of the grid-side converter.

[0085] It should be noted that the method of "obtaining the alternative grid-side phase information of the grid-side converter and performing current conversion on the grid-side three-phase current according to the alternative grid-side phase information to obtain the grid-side rotating DC current" has been described above and will not be repeated here.

[0086] Furthermore, the real-time active power transmitted by the grid-side converter is obtained based on the first output voltage and the selected DC current, including: by calculation To obtain real-time active power. This represents real-time active power.

[0087] It should be noted that the calculated active power P should be filtered by a filtering device to reduce its fluctuations.

[0088] Furthermore, grid-side phase information is obtained based on real-time active power, including: obtaining angular frequency information using preset droop control or virtual synchro control; integrating the angular frequency information to obtain grid-side phase information.

[0089] Optionally, angular frequency information is obtained by: utilizing preset droop control, through calculation... Angular frequency information is obtained. This refers to angular frequency information. The preset angular frequency threshold can be... ; This is the preset active power droop coefficient; This is the preset active power reference value.

[0090] Optionally, angular frequency information is obtained by: using a preset virtual synchronizer control, and through calculation... Angular frequency information is obtained. The preset virtual inertia constant, which simulates the rotational inertia of a synchronous generator, determines the system's response speed to power differences. The larger the value, the stronger the system inertia and the better the disturbance resistance, but the slower the dynamic response. This refers to the angular frequency information obtained previously.

[0091] Furthermore, a first switching signal is generated based on the grid-side phase information and the second output voltage of the grid-side converter, including: performing voltage compensation on the second output voltage to obtain a grid-side compensation voltage; using the grid-side phase information to perform voltage conversion on the grid-side compensation voltage to obtain a grid-side three-phase control voltage; acquiring the voltage across the DC capacitor in real time to obtain a reference capacitor voltage; and setting half of the reference capacitor voltage as a preset normalized parameter of the grid-side generation modulation wave module.

[0092] It should be noted that the grid-side modulation wave generation module is used to perform SPWM (Sinusoidal Pulse Width Modulation) modulation on the grid-side three-phase control voltage.

[0093] In such Figure 2 In the grid-side converter shown, points a, b, and c are the grid connection points, N is the neutral point of the AC power grid, and point O is the selected zero potential point, from which the phase voltage is obtained. , , ,as well as , , This is the DC side voltage.

[0094] make Given the modulation ratio, according to the SPWM modulation relationship, we have: Meanwhile, when the three-phase load is balanced, we have: .

[0095] Formula Substitute into the formula In the middle, then .in, This is the voltage between the neutral point N and the potential point 0.

[0096] Therefore, the three-phase voltages are:

[0097] Taking phase a as an example, the ratio of the phase voltage amplitude to the DC side voltage amplitude is: .

[0098] Therefore, the normalization parameter is set to 0.5u. dc This ensures that the output value of the current loop equals the actual voltage value at the PCC point. Considering the line impedance, the actual output value of the current loop will not be exactly the same as the voltage value at the PCC point, but the error will not be too large.

[0099] The grid-side three-phase control voltage is input to the grid-side modulation wave generation module to generate the first switching signal. This allows for voltage compensation of the second output voltage, resulting in a grid-side compensation voltage that can counteract grid voltage fluctuations and load changes, ensuring the stability of the grid-side compensation voltage. Then, the grid-side compensation voltage is converted using grid-side phase information to obtain the grid-side three-phase control voltage. The voltage across the DC capacitor is then acquired in real-time to obtain a reference capacitor voltage. Half of this reference capacitor voltage is set as the preset normalized parameter of the grid-side modulation wave generation module, and the grid-side three-phase control voltage is input to the same module to generate the first switching signal. Since the normalized parameter of the modulation wave generation module essentially affects the current loop output value through per-unit processing to achieve precise matching between the control signal and the actual physical quantity, setting half of the reference capacitor voltage as the preset normalized parameter ensures that the current loop output value is approximately equal to the PCC point voltage of the actual circuit, reducing control error and increasing control stability.

[0100] It should be noted that, as Figure 5 As shown, the grid-side compensation voltage includes the grid-side direct-axis compensation voltage and the grid-side quadrature-axis compensation voltage.

[0101] Specifically, voltage compensation is performed on the second output voltage to obtain the grid-side compensation voltage, i.e., by calculation. To obtain the grid-side direct-axis compensation voltage; among which, This is the grid-side direct-axis compensation voltage; This is the direct-axis output voltage of the second grid side; ω is the angular frequency of the synchronous motor; L is the inductance of the synchronous motor. This is calculated... To obtain the grid-side direct-axis compensation voltage; among which, This is the cross-axis compensation voltage on the grid side; This is the cross-axis output voltage of the second grid side.

[0102] It should be noted that the grid-side compensation voltage is converted using grid-side phase information to obtain the grid-side three-phase control voltage. This involves performing an inverse Park transformation on the grid-side compensation voltage using grid-side phase information to obtain the grid-side three-phase control voltage. The inverse Park transformation projects the direct-axis and quadrature-axis components onto the three-phase components.

[0103] Furthermore, a second switching signal is generated based on the actual capacitor voltage value and a preset capacitor voltage reference value. This includes: acquiring the three-phase current on the machine side; performing current conversion on the three-phase current on the machine side to obtain the machine-side rotating DC current; and generating the second switching signal based on the actual capacitor voltage value, the capacitor voltage reference value, and the machine-side rotating DC current. In this way, by acquiring the three-phase current on the machine side, performing current conversion on the three-phase current to obtain the machine-side rotating DC current, and then generating the second switching signal based on the actual capacitor voltage value, the second switching signal can be adjusted in real time according to the actual capacitor voltage value, thereby facilitating the maintenance of circuit control stability.

[0104] It should be noted that the three-phase current on the generator side includes the generator side... Corresponding phase current machine side Corresponding phase current and machine side Corresponding phase current .

[0105] Furthermore, the process of converting the three-phase current on the machine side to obtain the rotating DC current on the machine side includes: acquiring the phase information on the machine side; and performing Park transformation on the three-phase current on the machine side based on the phase information on the machine side to obtain the rotating DC current on the machine side.

[0106] Furthermore, the aircraft-side phase information is obtained, that is, the aircraft-side phase information is obtained through the magnetic flux observer.

[0107] The machine-side rotating DC current includes: machine-side direct-axis DC current and machine-side quadrature-axis DC current.

[0108] Furthermore, generating a second switching signal based on the actual capacitor voltage value, the reference capacitor voltage value, and the machine-side rotating DC current includes: inputting the voltage difference between the reference capacitor voltage value and the actual capacitor voltage value into a preset first machine-side proportional-integral control module to obtain a machine-side direct-axis reference current; obtaining a first difference between the machine-side direct-axis reference current and the machine-side direct-axis DC current; obtaining a second difference between a preset machine-side quadrature-axis reference current and the machine-side quadrature-axis DC current; and generating a second switching signal based on the first and second differences. In this way, by inputting the voltage difference between the reference capacitor voltage value and the actual capacitor voltage value into the preset first machine-side proportional-integral control module to obtain the machine-side direct-axis reference current, the influence of grid harmonics or load surges on the current can be isolated, improving the system's anti-disturbance capability. Then, by obtaining the first difference between the machine-side direct-axis reference current and the machine-side direct-axis DC current, and obtaining the second difference between the preset machine-side quadrature-axis reference current and the machine-side quadrature-axis DC current, and then generating a second switching signal based on the first and second differences, the dynamic generation of the second switching signal is achieved, thereby facilitating the maintenance of circuit control stability.

[0109] Further, generating a second switching signal based on the first and second differences includes: inputting the first difference into a preset second machine-side PI module to obtain a machine-side direct-axis output voltage; inputting the second difference into a preset third machine-side PI module to obtain a machine-side quadrature-axis output voltage; then performing voltage compensation on the machine-side direct-axis output voltage and the machine-side quadrature-axis output voltage respectively to obtain a machine-side direct-axis compensation voltage and a machine-side quadrature-axis compensation voltage; using machine-side phase information to perform voltage conversion on the machine-side direct-axis compensation voltage and the machine-side quadrature-axis compensation voltage to obtain a machine-side three-phase control voltage; and inputting the machine-side three-phase control voltage into a machine-side modulation wave generation module to generate the second switching signal.

[0110] It should be noted that the method of performing voltage compensation on the machine-side direct-axis output voltage and the machine-side quadrature-axis output voltage to obtain the machine-side direct-axis compensation voltage and the machine-side quadrature-axis compensation voltage is the same as the method of performing voltage compensation on the second output voltage to obtain the grid-side compensation voltage; and the method of using grid-side phase information to perform voltage conversion on the grid-side compensation voltage to obtain the grid-side three-phase control voltage is the same, and will not be repeated here.

[0111] For details, please refer to Figure 6 , Figure 6 This is a flowchart illustrating a wide short-circuit ratio control method for a full-power pumped-storage unit, as shown in an exemplary embodiment of this application.

[0112] Combination Figure 6 As shown, embodiments of this disclosure provide a method for controlling Figure 1 The method for a full-power pumped-storage unit shown includes:

[0113] Step S601: Obtain the first output voltage of the grid-side current inner loop and the grid-side three-phase current supplied by the grid-side converter to the grid.

[0114] Step S602: Input the first output voltage and the grid-side three-phase current into the reactive power droop loop to obtain the reference voltage.

[0115] Step S603: Based on the first output voltage, the reference voltage is tracked using a preset voltage and current dual closed-loop control strategy to obtain the second output voltage of the grid-side current loop.

[0116] Step S604: Obtain grid-side phase information based on the first output voltage and the grid-side three-phase current supplied to the grid by the grid-side converter.

[0117] Step S605: Generate a first switching signal based on the grid-side phase information and the second output voltage of the grid-side converter, so as to drive the grid-side converter using the first switching signal.

[0118] Step S606: Acquire the voltage across the DC capacitor to obtain the actual value of the capacitor voltage.

[0119] Step S607: Generate a second switching signal based on the actual value of the capacitor voltage and the preset reference value of the capacitor voltage, so as to drive the machine-side converter using the second switching signal.

[0120] In this embodiment, the first output voltage from the grid-side current inner loop and the grid-side three-phase current supplied to the grid by the grid-side converter are input into the reactive power droop loop to obtain a reference voltage. Then, a preset voltage-current dual closed-loop control strategy is used to track the reference voltage, obtaining the second output voltage from the grid-side current loop. A first switching signal is then generated based on the grid-side phase information of the grid-side converter and the second output voltage to drive the grid-side converter. The voltage across the DC capacitor is then acquired to obtain the actual capacitor voltage value. A second switching signal is generated based on the actual capacitor voltage value and a preset capacitor voltage reference value to drive the generator-side converter. Compared to existing technologies, this solution uses the first output voltage from the grid-side current inner loop to replace the voltage at the PCC point in the actual circuit for voltage feedback. The grid-side converter using droop control is not equivalent to a voltage source, reducing the likelihood of subsynchronous oscillations leading to instability when connected in parallel with a strong grid, thereby improving the control stability of the full-power pumped-storage unit.

[0121] In some embodiments, such as Figure 7 As shown, Figure 7 This is a flowchart illustrating a wide short-circuit ratio control process for a full-power pumped-storage unit, as shown in an exemplary embodiment of this application.

[0122] like Figure 7As shown, the grid-side three-phase current supplied by the grid-side converter 102 to the grid 701 The grid-side phase information, which is the previously acquired grid-side phase information, is input into the grid-side first converter 702 for current conversion to obtain the grid-side rotating DC current. Then, using the first output voltage... Power calculations are performed using the grid-side rotating DC current to obtain the real-time reactive power and real-time active power transmitted by the grid-side converter. Then, a reference voltage is obtained through droop control or virtual synchronous machine control. and network-side phase information .

[0123] Obtain the reference voltage in the outer loop of the grid-side voltage. With the first grid side direct axis output voltage The first grid-side voltage deviation is calculated; this first grid-side voltage deviation is input into a preset first grid-side PI (Proportional-Integral) module 501 to obtain a first grid-side current reference value. The preset grid-side quadrature-axis voltage reference value and the first grid-side quadrature-axis output voltage are then obtained. The second grid-side voltage deviation is calculated; this second grid-side voltage deviation is input into the preset second grid-side PI module 502 to obtain the second grid-side current reference value. The preset grid-side quadrature-axis voltage reference value is 0.

[0124] In the inner loop of the grid-side current, obtain the first grid-side current reference value and the grid-side direct-axis DC current. The first grid-side current deviation is calculated; the first grid-side current deviation is input into the preset third grid-side PI module 503 to obtain the second grid-side direct-axis output voltage. Simultaneously, the direct-axis output voltage on the second grid side... Feedback to the grid-side voltage outer loop and power calculation process will be used as the first grid-side direct-axis output voltage for the next control cycle. Obtain the second grid-side current reference value and the grid-side quadrature-axis DC current. The second grid-side current deviation is calculated; the second grid-side current deviation is input into the preset fourth grid-side PI module 504 to obtain the second grid-side quadrature axis output voltage. Simultaneously, the second grid side quadrature axis output voltage Feedback to the outer loop of the grid-side voltage and during power calculations will be used as the first grid-side quadrature-axis output voltage for the next control cycle. Then through For the second output voltage, i.e. Compensation is performed to obtain the grid-side compensation voltage.

[0125] The grid-side compensation voltage and grid-side phase information are input to the grid-side second converter 703 for voltage conversion to obtain the grid-side three-phase control voltage. Then, the voltage across the DC capacitor is acquired in real time to obtain the reference capacitor voltage; half of the reference capacitor voltage is set as the preset normalization parameter of the grid-side generation modulation wave module 704; the grid-side three-phase control voltage is input to the grid-side generation modulation wave module 704 to generate a first switching signal, which is used to drive the grid-side converter.

[0126] Then, the voltage across the DC capacitor is re-acquired to obtain the actual value of the capacitor voltage. Obtain the three-phase current on the generator side. Then, the output engine-side phase information is obtained through the flux linkage observer 705. Then, the three-phase current and phase information on the machine side are input into the first converter 706 on the machine side for current conversion to obtain the machine-side rotating DC current. .

[0127] In the outer loop of the machine-side voltage, the capacitor voltage reference value is... Actual value of capacitor voltage The voltage difference between the two is input to the preset first machine-side PI module 707 to obtain the machine-side direct-axis reference current.

[0128] Within the machine-side current inner loop, obtain the machine-side direct-axis reference current and the machine-side direct-axis DC current. The first difference between the two values ​​is input into the preset second machine-side PI module 708 to obtain the machine-side direct-axis output voltage. Then, through... Voltage compensation is performed on the direct-axis output voltage on the machine side to obtain the direct-axis compensated voltage. Preset machine-side quadrature-axis reference current and machine-side quadrature-axis DC current are then acquired. The second difference between the two values. The preset machine-side quadrature-axis reference current can be 0. Then, the second difference is input to the preset third machine-side PI module 709 to obtain the machine-side quadrature-axis output voltage. Then, through... Voltage compensation is performed on the machine-side quadrature axis output voltage to obtain the machine-side quadrature axis compensation voltage.

[0129] The grid-side phase information and grid-side compensation voltage, namely the machine-side direct-axis compensation voltage and the machine-side quadrature-axis compensation voltage, are input together into the machine-side second converter 710 for voltage conversion to obtain the machine-side three-phase control voltage. Then, the machine-side three-phase control voltage is input into the machine-side modulation wave generation module 711 to generate a second switching signal, which is used to drive the machine-side converter 103.

[0130] In some embodiments, the short-circuit ratio is a quantitative indicator of the strength of the power grid; a higher short-circuit ratio indicates a stronger grid, and vice versa. The short-circuit ratio is calculated using the following formula: It can be seen that the short-circuit ratio The value is related to the rated value of the power grid bus voltage. It is proportional to the square of the power and is related to the rated power of the power grid. , Inversely proportional.

[0131] If a full-power variable-speed pumped storage unit adopts traditional power synchronization control, then by reducing... Increase or increase ,make The value decreases.

[0132] However, when reduced At the same power level, a larger current is required to transmit the same amount of power, which leads to greater losses and poses a greater challenge to the line's current-carrying capacity. Increasing... It will also increase the current in the line, and the resulting impact is comparable to the reduction. Similar. Increase In such cases, increasing the line inductance is typically chosen, which leads to increased reactive power demand and necessitates the addition of components that generate reactive power. However, if the method proposed in this invention is adopted, the full-power variable-speed pumped storage unit uses a wide short-circuit ratio grid-type control, as it can adapt to larger [various applications / conditions]. No need to reduce Increase or increase To reduce If the values ​​are accurate, the aforementioned problems will not exist. Smaller line equivalent inductive reactance can reduce reactive power loss, and the design of the rated values ​​of bus voltage and rated power can more easily meet actual requirements. This effectively improves the short-circuit ratio range that the full-power variable speed pumped storage unit can operate stably, enhances the stability of the full-power variable speed pumped storage unit, and saves on the cost of voltage sensors, thereby helping to reduce costs while improving the stability of the power grid.

[0133] For details, please refer to Figure 8 , Figure 8 Simulation diagrams of current for grid-side converters with traditional grid-type control and wide short-circuit ratio grid-type control under a strong power grid with a short-circuit ratio of 21.6.

[0134] like Figure 8 As shown, (a) is a current simulation diagram of a grid-side converter with conventional grid-type control. (b) is a current simulation diagram of a grid-side converter with wide short-circuit ratio grid-type control according to this application. The red, blue, and yellow current waveforms represent the three-phase current output by the grid-side converter.

[0135] like Figure 8As shown, the waveform in (a) has more sawtooth edges, while the waveform in (b) has fewer sawtooth edges, or even none. It can be seen that in a strong power grid environment, the grid-side converter controlled by the wide short-circuit ratio grid type can operate stably, while the traditional grid-side control will become unstable.

[0136] Combination Figure 9 As shown, embodiments of this disclosure provide a method for controlling such Figure 1 The device 900 shown is a full-power pumped storage unit, which includes a control module 901, a data acquisition module 902, and a generation module 903.

[0137] The control module 901 is configured to control the grid-side converter using a preset wide short-circuit ratio grid-type control strategy. The wide short-circuit ratio grid-type control strategy includes: tracking a reference voltage using a preset voltage-current dual closed-loop control strategy based on a first output voltage to obtain a second output voltage of the grid-side current loop; the voltage-current dual closed-loop control strategy performs voltage tracking through an outer grid-side voltage loop and an inner grid-side current loop; the reference voltage is obtained based on the first output voltage and the grid-side three-phase current supplied by the grid-side converter to the grid; the first output voltage is the inner grid-side current loop. The output voltage; a first switching signal is generated based on the grid-side phase information and the second output voltage of the grid-side converter, so as to drive the grid-side converter using the first switching signal; the grid-side phase information is obtained by the grid-side three-phase current supplied to the grid by the grid-side converter based on the first output voltage; the acquisition module 902 is configured to acquire the voltage across the DC capacitor to obtain the actual value of the capacitor voltage; the generation module 903 is configured to generate a second switching signal based on the actual value of the capacitor voltage and a preset capacitor voltage reference value, so as to drive the machine-side converter using the second switching signal.

[0138] The full-power pumped-storage unit wide short-circuit ratio control device provided in this embodiment controls the grid-side converter using a preset wide short-circuit ratio grid configuration control strategy. Specifically, it tracks a reference voltage based on a first output voltage using a preset voltage-current dual closed-loop control strategy to obtain a second output voltage of the grid-side current loop. The reference voltage is obtained by combining the first output voltage from the grid-side current inner loop with the grid-side three-phase current supplied to the grid by the grid-side converter. Then, a first switching signal is generated based on the grid-side phase information of the grid-side converter and the second output voltage to drive the grid-side converter. Furthermore, the voltage across the DC capacitor is acquired to obtain the actual capacitor voltage value, and a second switching signal is generated based on the actual capacitor voltage value and a preset capacitor voltage reference value to drive the generator-side converter. Compared to existing technologies, this solution uses the first output voltage of the grid-side current inner loop to replace the voltage at the PCC point in the actual circuit for voltage feedback. The grid-side converter using droop control will not be equivalent to a voltage source, reducing the occurrence of subsynchronous oscillations that could lead to instability when connected in parallel with a strong grid, thereby improving the control stability of the full-power pumped storage unit.

[0139] Furthermore, the full-power pumped-storage unit wide short-circuit ratio control device also includes a reference voltage acquisition module. The reference voltage acquisition module is configured to acquire the reference voltage based on the first output voltage and the grid-side three-phase current supplied to the grid by the grid-side converter in the following manner: acquiring alternative grid-side phase information of the grid-side converter operation; performing current conversion on the grid-side three-phase current based on the alternative grid-side phase information to obtain the grid-side rotating DC current; acquiring the real-time reactive power transmitted by the grid-side converter based on the first output voltage and the grid-side rotating DC current; and acquiring the reference voltage based on the real-time reactive power.

[0140] Furthermore, the full-power pumped-storage unit wide short-circuit ratio control device also includes a grid-side phase information acquisition module. The grid-side phase information acquisition module is configured to acquire the following information based on the first output voltage and the grid-side three-phase current supplied to the grid by the grid-side converter: acquiring alternative grid-side phase information for the grid-side converter operation; performing current conversion on the grid-side three-phase current based on the alternative grid-side phase information to obtain the grid-side rotating DC current; acquiring the real-time active power transmitted by the grid-side converter based on the first output voltage and the selected DC current; and acquiring the grid-side phase information based on the real-time active power.

[0141] Furthermore, the first generation module is configured to generate a first switching signal based on the grid-side phase information and the second output voltage of the grid-side converter in the following manner: performing voltage compensation on the second output voltage to obtain a grid-side compensation voltage; performing voltage conversion on the grid-side compensation voltage using the grid-side phase information to obtain a grid-side three-phase control voltage; acquiring the voltage across the DC capacitor in real time to obtain a reference capacitor voltage; setting half of the reference capacitor voltage as a preset normalization parameter of the grid-side generation modulation wave module; and inputting the grid-side three-phase control voltage into the grid-side generation modulation wave module to generate the first switching signal.

[0142] Furthermore, the generation module is configured to generate a second switching signal based on the actual value of the capacitor voltage and a preset capacitor voltage reference value in the following manner: acquiring the three-phase current on the machine side; performing current conversion on the three-phase current on the machine side to obtain the rotating DC current on the machine side; and generating the second switching signal based on the actual value of the capacitor voltage, the capacitor voltage reference value, and the rotating DC current on the machine side.

[0143] Furthermore, the machine-side rotating DC current includes the machine-side direct-axis DC current and the machine-side quadrature-axis DC current; the generation module is configured to generate a second switching signal based on the actual value of the capacitor voltage, the reference value of the capacitor voltage, and the machine-side rotating DC current in the following manner: inputting the voltage difference between the reference value of the capacitor voltage and the actual value of the capacitor voltage into a preset first machine-side proportional-integral control module to obtain the machine-side direct-axis reference current; obtaining a first difference between the machine-side direct-axis reference current and the machine-side direct-axis DC current; obtaining a second difference between a preset machine-side quadrature-axis reference current and the machine-side quadrature-axis DC current; and generating a second switching signal based on the first difference and the second difference.

[0144] Combination Figure 10 As shown, this disclosure provides another wide short-circuit ratio control device for a full-power pumped-storage unit, including a processor 1001 and a memory 1002. Optionally, the device may further include a communication interface 1003 and a bus 1004. The processor 1001, communication interface 1003, and memory 1002 can communicate with each other via the bus 1004. The communication interface 1003 can be used for information transmission. The processor 1001 can call logic instructions in the memory 1002 to execute the wide short-circuit ratio control method for the full-power pumped-storage unit described in the above embodiment.

[0145] Furthermore, the logic instructions in the aforementioned memory 1002 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium.

[0146] The memory 1002, as a storage medium, can be used to store software programs and computer-executable programs, such as the program instructions / modules corresponding to the methods in the embodiments of this disclosure. The processor 1001 executes functional applications and data processing by running the program instructions / modules stored in the memory 1002, thereby implementing the wide short-circuit ratio control method for full-power pumped-storage units in the above embodiments.

[0147] The memory 1002 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the terminal device. Furthermore, the memory 1002 may include high-speed random access memory and may also include non-volatile memory.

[0148] The full-power pumped-storage unit wide short-circuit ratio control device provided in this embodiment tracks a reference voltage based on a preset voltage-current dual closed-loop control strategy according to a first output voltage, obtaining a second output voltage of the grid-side current loop. The reference voltage is obtained by using the first output voltage from the grid-side current inner loop and the grid-side three-phase current supplied to the grid by the grid-side converter. Then, a first switching signal is generated based on the grid-side phase information of the grid-side converter and the second output voltage to drive the grid-side converter. The voltage across the DC capacitor is then acquired to obtain the actual capacitor voltage value, and a second switching signal is generated based on the actual capacitor voltage value and a preset capacitor voltage reference value to drive the generator-side converter. Compared to existing technologies, this solution uses the first output voltage from the grid-side current inner loop to replace the voltage at the PCC point in the actual circuit for voltage feedback. The grid-side converter using droop control is not equivalent to a voltage source, reducing the likelihood of subsynchronous oscillations leading to instability when connected in parallel with a strong grid, thereby improving the control stability of the full-power pumped-storage unit.

[0149] This disclosure provides an electronic device, including, as shown in the embodiments below. Figure 9 or Figure 10 The diagram shows a wide short-circuit ratio control device for a full-power pumped-storage unit.

[0150] This disclosure provides a storage medium storing computer-executable instructions configured to execute the above-described wide short-circuit ratio control method for full-power pumped-storage units.

[0151] The aforementioned storage media can be either transient computer-readable storage media or non-transitory computer-readable storage media. Non-transitory storage media include various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks, and can also be transient storage media.

[0152] The foregoing description and accompanying drawings fully illustrate embodiments of this disclosure to enable those skilled in the art to practice them. Other embodiments may include structural, logical, electrical, procedural, and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the order of operation may vary. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. Moreover, the terminology used in this application is for describing embodiments only and is not intended to limit the claims. As used in the description of embodiments and claims, the singular forms “a,” “an,” and “the” are intended to equally include the plural forms unless the context clearly indicates otherwise. Similarly, the term “and / or” as used in this application means including one or more of the associated listed items and all possible combinations thereof. Additionally, when used in this application, the term "comprise" and its variations "comprises" and / or "comprising" refer to the presence of stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof. Without further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the process, method, or apparatus that includes said element. In this document, each embodiment may focus on the differences from other embodiments, and similar or identical parts between embodiments can be referred to mutually. For methods, products, etc., disclosed in the embodiments, if they correspond to the method section disclosed in the embodiments, the relevant parts can be referred to the description of the method section.

[0153] 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, or a combination of computer software and electronic hardware. 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 implementation should not be considered beyond the scope of the embodiments of this disclosure. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0154] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than that shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different blocks may also occur in a different order than disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. Each block in a block diagram and / or flowchart, and combinations of blocks in a block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

Claims

1. A method for wide short-circuit ratio control of a full-power pumped-storage unit, characterized in that, The full-power pumped-storage unit includes a pump-turbine, a grid-side converter, a turbine-side converter, and a synchronous motor; a DC capacitor is connected in parallel between the grid-side converter and the turbine-side converter; the pump-turbine converts the potential energy of water into electrical energy through the grid-side converter, the turbine-side converter, and the synchronous motor to supply power to the grid; the method includes: The grid-side converter is controlled using a preset wide short-circuit ratio grid configuration control strategy. This strategy includes: tracking a reference voltage using a preset voltage-current dual-loop control strategy based on a first output voltage to obtain a second output voltage from the grid-side current loop; the voltage-current dual-loop control strategy performs voltage tracking through an outer grid-side voltage loop and an inner grid-side current loop; the reference voltage is obtained based on the first output voltage and the grid-side three-phase current supplied by the grid-side converter to the grid; the first output voltage is the voltage output by the inner grid-side current loop; a first switching signal is generated based on the grid-side phase information of the grid-side converter and the second output voltage to drive the grid-side converter; the grid-side phase information is obtained based on the first output voltage and the grid-side three-phase current supplied by the grid-side converter to the grid. The voltage across the DC capacitor is acquired to obtain the actual value of the capacitor voltage; A second switching signal is generated based on the actual value of the capacitor voltage and the preset reference value of the capacitor voltage, so as to drive the machine-side converter using the second switching signal.

2. The method according to claim 1, characterized in that, The reference voltage is obtained based on the first output voltage and the grid-side three-phase current supplied to the grid by the grid-side converter in the following manner: Obtain the alternative grid-side phase information for the operation of the grid-side converter; Based on the candidate grid-side phase information, the grid-side three-phase current is converted to obtain the grid-side rotating DC current. The real-time reactive power transmitted by the grid-side converter is obtained based on the first output voltage and the grid-side rotating DC current. The reference voltage is obtained based on the real-time reactive power.

3. The method according to claim 1, characterized in that, The grid-side phase information is obtained based on the first output voltage and the grid-side three-phase current supplied to the grid by the grid-side converter in the following manner: Obtain the alternative grid-side phase information for the operation of the grid-side converter; Based on the candidate grid-side phase information, the grid-side three-phase current is converted to obtain the grid-side rotating DC current. The real-time active power transmitted by the grid-side converter is obtained based on the first output voltage and the selected DC current. The grid-side phase information is obtained based on the real-time active power.

4. The method according to claim 1, characterized in that, The step of generating a first switching signal based on the grid-side phase information of the grid-side converter and the second output voltage includes: The second output voltage is voltage compensated to obtain the grid-side compensation voltage; The grid-side phase information is used to perform voltage conversion on the grid-side compensation voltage to obtain the grid-side three-phase control voltage. The voltage across the DC capacitor is acquired in real time to obtain the reference capacitor voltage; Half of the reference capacitor voltage is set as the preset normalized parameter of the grid-side generated modulation wave module. The grid-side three-phase control voltage is input to the grid-side modulation wave generation module to generate the first switching signal.

5. The method according to claim 1, characterized in that, The step of generating a second switching signal based on the actual value of the capacitor voltage and a preset capacitor voltage reference value includes: Obtain the three-phase current on the machine side; The three-phase current on the machine side is converted to obtain the rotating DC current on the machine side. The second switching signal is generated based on the actual value of the capacitor voltage, the reference value of the capacitor voltage, and the rotating DC current on the machine side.

6. The method according to claim 5, characterized in that, The machine-side rotating DC current includes a machine-side direct-axis DC current and a machine-side quadrature-axis DC current; the generation of the second switching signal based on the actual value of the capacitor voltage, the reference value of the capacitor voltage, and the machine-side rotating DC current includes: The voltage difference between the capacitor voltage reference value and the actual capacitor voltage value is input into a preset first machine-side proportional-integral control module to obtain the machine-side direct-axis reference current. Obtain the first difference between the machine-side direct-axis reference current and the machine-side direct-axis DC current; Obtain the second difference between the preset machine-side quadrature axis reference current and the machine-side quadrature axis DC current; The second switching signal is generated based on the first difference and the second difference.

7. A wide short-circuit ratio control device for a full-power pumped-storage unit, characterized in that, The full-power pumped-storage unit includes a pump-turbine, a grid-side converter, a turbine-side converter, and a synchronous motor; a DC capacitor is connected in parallel between the grid-side converter and the turbine-side converter; the pump-turbine converts the potential energy of water into electrical energy through the grid-side converter, the turbine-side converter, and the synchronous motor to supply power to the grid; the device includes: The control module is configured to control the grid-side converter using a preset wide short-circuit ratio grid configuration control strategy. The wide short-circuit ratio grid configuration control strategy includes: tracking a reference voltage using a preset voltage-current dual-loop control strategy based on a first output voltage to obtain a second output voltage of the grid-side current loop; the voltage-current dual-loop control strategy performs voltage tracking through an outer grid-side voltage loop and an inner grid-side current loop; the reference voltage is obtained based on the first output voltage and the grid-side three-phase current supplied by the grid-side converter to the grid; the first output voltage is the voltage output by the inner grid-side current loop; a first switching signal is generated based on the grid-side phase information of the grid-side converter and the second output voltage to drive the grid-side converter; the grid-side phase information is obtained based on the first output voltage and the grid-side three-phase current supplied by the grid-side converter to the grid. The acquisition module is configured to acquire the voltage across the DC capacitor and obtain the actual value of the capacitor voltage. The generation module is configured to generate a second switching signal based on the actual value of the capacitor voltage and a preset capacitor voltage reference value, so as to drive the machine-side converter using the second switching signal.

8. A wide short-circuit ratio control device for a full-power pumped-storage unit, comprising a processor and a memory storing program instructions, characterized in that, The processor is configured to execute the wide short-circuit ratio control method for full-power pumped-storage units as described in any one of claims 1 to 6 when running the program instructions.

9. An electronic device, characterized in that, Includes the wide short-circuit ratio control device for full-power pumped storage units as described in claim 7 or 8.

10. A storage medium storing program instructions, characterized in that, When the program instructions are executed, they perform the wide short-circuit ratio control method for full-power pumped storage units as described in any one of claims 1 to 6.

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