Grid-forming power source system, control method and apparatus therefor and controller therefor, and medium

Abstract

The present application relates to a grid-forming power source system, a control method and apparatus therefor and a controller therefor, and a medium, and belongs to the technical field of power. The grid-forming power source system comprises: a new-energy power generation unit, which is connected to a power grid by means of a power output line; and an energy storage unit, which is connected to the power output line for the new-energy power generation unit, and is connected to the power grid after being connected in parallel with the new-energy power generation unit, wherein the energy storage unit comprises an energy storage converter, and the energy storage converter is used for controlling the magnitude of an output current of the energy storage unit, such that the total current output by the grid-forming power source system meets power grid requirements. By means of the embodiments of the present application, the safety and stability of a power system can be improved.

Description

Grid-type power systems and their control methods, devices, controllers, and dielectrics

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411586959.8, filed on November 8, 2024, entitled “Grid-type power supply system and control method, device, controller and medium thereof”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application belongs to the field of power technology, and in particular relates to a grid-type power supply system and its control method, device, controller and medium. Background Technology

[0004] With the continuous development of new energy technologies, the proportion of new energy power generation devices using new energy technologies in the power system is increasing. The reverse distribution between new energy sources and electrical load devices means that the generated electricity needs to be transmitted over long distances through AC / DC systems to the power grid. Since the voltage in the power system is established by the grid, the increasing proportion of new energy devices in the power system leads to a continuous decrease in the grid's clamping ability on the voltage at the grid connection point. This results in low grid strength and weak anti-interference capabilities, thus affecting the safety and stability of the power system.

[0005] Application content

[0006] This application provides a grid-type power system and its control method, device, controller, and medium, which can improve the safety and stability of the power system.

[0007] On one hand, this application provides a grid-connected power system, including: a new energy power generation unit connected to the power grid via a power transmission line; and an energy storage unit connected to the power transmission line of the new energy power generation unit and connected to the power grid in parallel with the new energy power generation unit. The energy storage unit includes an energy storage converter, which is used to control the magnitude of the output current of the energy storage unit so that the total output current of the grid-connected power system meets the grid demand.

[0008] According to one embodiment of this application, the new energy power generation unit includes power generation equipment and a converter. The power generation equipment is connected to one end of the converter, and the other end of the converter is connected to the power grid through a power transmission line.

[0009] According to any of the foregoing embodiments of one aspect of this application, the power generation equipment includes at least one of the following: a doubly-fed wind turbine, a direct-drive wind turbine, a semi-direct-drive wind turbine, a squirrel-cage wind turbine, a permanent magnet wind turbine, an electrically excited wind turbine, a horizontal axis wind turbine, a vertical axis wind turbine, a photovoltaic power generation unit, a wind-solar integrated generator, and a wind-solar-storage hybrid power generation system.

[0010] According to any of the foregoing embodiments of one aspect of this application, the grid-connected power system further includes: a signal acquisition unit, used to acquire the voltage and / or current values ​​at the grid connection point of the grid-connected power system, the voltage and / or current values ​​output by the new energy power generation unit, and the current and / or voltage values ​​output by the energy storage unit.

[0011] On the other hand, embodiments of this application also provide a control method for a grid-connected power system, applied to the grid-connected power system of the first aspect. The method includes: calculating a reference value of the total output current of the grid-connected power system based on the amplitude and phase angle of the internal potential of the grid-connected power system; calculating a voltage setpoint of the energy storage unit based on the current value output by the new energy generation unit, the current value output by the energy storage unit, and the total current reference value; and controlling the operation of the switching transistor in the energy storage converter based on the voltage setpoint of the energy storage unit, thereby changing the magnitude of the output current of the energy storage unit so that the total output current of the grid-connected power system meets the grid demand.

[0012] According to one aspect of this application, the internal potential amplitude is calculated based on the reactive power command received by the grid-connected power system, the measured reactive power output of the grid-connected power system, and the reference voltage value at the grid connection point; or, the internal potential amplitude is calculated based on the target voltage value at the grid connection point and the measured voltage value at the grid connection point issued by the grid dispatch center, and the reference internal potential value of the grid-connected power system; or, the internal potential amplitude is calculated based on the target voltage value at the grid connection point, the measured voltage value at the grid connection point, the measured reactive power output of the grid-connected power system, and the reference internal potential value of the grid-connected power system issued by the grid dispatch center.

[0013] According to any of the foregoing embodiments of one aspect of this application, the internal potential amplitude is calculated based on the reactive power command received by the grid-connected power system, the measured reactive power output by the grid-connected power system, and the grid-connected point voltage reference value. This includes: obtaining a first difference between the reactive power command received by the grid-connected power system and the measured reactive power output by the grid-connected power system; performing a PI operation on the first difference to obtain a first voltage difference; and using the sum of the first voltage difference and the grid-connected point voltage reference value as the internal potential amplitude of the grid-connected power system.

[0014] According to any of the foregoing embodiments of one aspect of this application, in response to the change in the grid connection point voltage measurement value exceeding a preset threshold, the method further includes: performing droop control based on the grid connection point voltage measurement value, the internal potential reference value of the grid-connected power system, and the sum value to obtain the internal potential amplitude of the grid-connected power system.

[0015] According to any of the foregoing embodiments of this application, the method further includes: calculating the internal potential phase angle based on the active power of the new energy power generation unit, the active power of the grid-connected power system, and the active power command issued by the power grid to the energy storage unit.

[0016] According to any of the foregoing embodiments of one aspect of this application, the active power target value issued by the energy storage unit is calculated based on the active power on the side of the new energy power generation unit and the active power command issued by the grid to the energy storage unit; the active power target value is controlled by power synchronization based on the active power at the grid connection point of the grid-connected power system to obtain the internal potential phase angle of the grid-connected power system.

[0017] In another aspect, embodiments of this application provide a control device for a grid-connected power system, applied to the grid-connected power system of the first aspect; the device includes: a reference current determination module, used to calculate a reference value of the total output current of the grid-connected power system based on the amplitude and phase angle of the internal potential of the grid-connected power system; a voltage setpoint determination module, used to calculate a voltage setpoint of the energy storage unit based on the current value output by the new energy generation unit, the current value output by the energy storage unit, and the total current reference value; and a control module, used to control the operation of the switching transistor in the energy storage converter based on the voltage setpoint of the energy storage unit, thereby changing the magnitude of the output current of the energy storage unit so that the total output current of the grid-connected power system meets the grid demand.

[0018] In another aspect, embodiments of this application provide a controller for a grid-type power system, including: a processor and a memory storing computer program instructions; the processor executes the computer program instructions to implement the control method for the grid-type power system of the second aspect.

[0019] In another aspect, embodiments of this application provide a computer-readable storage medium storing computer program instructions, which, when executed by a processor, implement the control method for the grid-type power system of the second aspect.

[0020] This application provides a grid-connected power system and its control method, device, controller, and medium. A new energy power generation unit is connected to the power grid via a power transmission line, and an energy storage unit is connected to the power transmission line of the new energy power generation unit to form a grid-connected power system. Based on the internal potential amplitude and phase angle of the grid-connected power system, a reference value for the total output current of the grid-connected power system is calculated. Based on the current values ​​output by the new energy power generation unit, the current values ​​output by the energy storage unit, and the total current reference value, the voltage setpoint required to control the switching transistors in the energy storage converter is obtained. The energy storage converter is controlled according to this voltage setpoint, thereby controlling the magnitude of the output current of the energy storage unit, and ultimately controlling the total output current of the grid-connected power system to meet the grid demand. This enables the grid-connected power system to quickly and actively provide inertia support, improving the safety and stability of the power system. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 is a schematic diagram of a grid-type power system provided in an embodiment of this application;

[0023] Figure 2 is a schematic diagram of a grid-type power system provided in another embodiment of this application;

[0024] Figure 3 is a schematic diagram of the structure of a grid-type power system provided in another embodiment of this application;

[0025] Figure 4 is a flowchart of a control method for a grid-type power system provided in an embodiment of this application;

[0026] Figure 5 is a logical schematic diagram of an example of obtaining the internal potential amplitude provided in an embodiment of this application;

[0027] Figure 6 is a logical schematic diagram of another example of obtaining the internal potential amplitude provided by the embodiments of this application;

[0028] Figure 7 is a logical schematic diagram of another example of obtaining the internal potential amplitude provided by the embodiments of this application;

[0029] Figure 8 is a logical schematic diagram of another example of obtaining the internal potential amplitude provided by the embodiments of this application;

[0030] Figure 9 is a logical schematic diagram of an example of obtaining the internal potential phase angle provided in an embodiment of this application;

[0031] Figure 10 is a logic diagram of an example of obtaining a total current reference value according to an embodiment of this application;

[0032] Figure 11 is a logical schematic diagram of an example of obtaining a voltage setpoint provided in an embodiment of this application;

[0033] Figure 12 is a logic diagram of another example of obtaining a voltage setpoint provided in an embodiment of this application;

[0034] Figure 13 is a schematic diagram of the structure of the control device for a grid-type power system provided in an embodiment of this application;

[0035] Figure 14 is a schematic diagram of the structure of the controller of a grid-type power system provided in an embodiment of this application. Detailed Implementation

[0036] The features and exemplary embodiments of various aspects of this application will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a comprehensive understanding of this application. However, it will be apparent to those skilled in the art that this application can be implemented without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of this application by illustrating examples. In the accompanying drawings and the following description, at least some well-known structures and techniques are not shown to avoid unnecessarily obscuring the application; and, for clarity, the dimensions of some structures may be exaggerated. Furthermore, the features, structures, or characteristics described below can be combined in any suitable manner in one or more embodiments.

[0037] To better understand this application, the following describes in detail, with reference to Figures 1 to 14, the grid-type power system and its control method, device, controller and medium provided in the embodiments of this application.

[0038] With the continuous development of new energy technologies, the proportion of new energy power generation devices using new energy technologies in the power system is increasing. The reverse distribution between new energy sources and electrical load devices necessitates that the generated electricity from these devices be transmitted over long distances to the power grid via AC / DC systems. Since the voltage in the power system is established by the grid, the increasing proportion of new energy devices in the power system leads to a continuous decline in the grid's clamping ability over the voltage at the grid connection point. This results in low grid strength, weak anti-interference capabilities, and various stability problems in the power system, with voltage issues being particularly prominent, seriously threatening the safe and stable operation of the power grid and various equipment within the power system.

[0039] This application provides a grid-type power system and its control method, device, controller, and medium. The grid-type power system is formed by connecting energy storage units to the power transmission line between the new energy power generation source and the power grid. By controlling the grid-type power system, it can provide a larger short-circuit support current during grid faults, reducing the scope of fault impact. It can also provide power support quickly and proactively when the power system experiences frequency disturbances, stabilizing the frequency of the power system and ensuring the safety and stability of the power system.

[0040] The following describes the grid-type power supply system and its control method, device, controller, and medium provided in this application.

[0041] The first aspect of this application provides a grid-connected power system. Figure 1 is a schematic diagram of the structure of a grid-connected power system provided in an embodiment of this application. As shown in Figure 1, the grid-connected power system 10 may include a new energy power generation unit 11 and an energy storage unit 12.

[0042] The new energy power generation unit 11 is connected to the power grid 21 via power transmission line 13. The new energy power generation unit 11 can be a single new energy power generation device, multiple new energy power generation devices connected to a single power transmission line 13, a new energy power station, or a new energy cluster formed by mixed types of new energy power stations. The voltage level of the power transmission line 13 can be set according to the output voltage level of the connected new energy power generation unit 11. For example, the voltage level of the power transmission line 13 may include, but is not limited to, 380V, 690V, 1140V, 10kV, 35kV, 66kV, 110kV, and 220kV. Specifically, the new energy power generation unit 11 can be connected to the grid connection point A4 via the power transmission line 13, thereby connecting to the power grid 21.

[0043] Energy storage unit 12 can be connected to the power transmission line 13 of the new energy power generation unit 11 and connected to the power grid in parallel with the new energy power generation unit 11. Energy storage unit 12 may include energy storage device 121 and energy storage converter 122. Energy storage device 121 can be connected to power transmission line 13 through energy storage converter 122. A2 is the connection point between energy storage converter 122 and power transmission line 13. Energy storage device 121 may include, but is not limited to, batteries, flywheel devices, supercapacitors, etc. Energy storage converter 122 may include multiple switching transistors, which may include, but are not limited to, insulated-gate bipolar transistors (IGBTs). By controlling energy storage converter 122, the current output from energy storage device 121 to power transmission line 13 can be controlled, that is, the output current of energy storage unit 12 can be controlled. The energy storage converter 122 controls the magnitude of the output current of the energy storage unit 12 so that the total output current of the grid-type power system 10 meets the grid demand.

[0044] As shown in Figure 1, point A2 represents the connection point between the energy storage unit 12 and the power transmission line 13, and point A4 represents the grid connection point of the grid-connected power system 10. In some embodiments, the grid-connected power system may further include a signal acquisition unit. The signal acquisition unit can be used to acquire the voltage and / or current values ​​at the grid connection point of the grid-connected power system 10 (i.e., the voltage and / or current values ​​at point A4 in Figure 1), the voltage and / or current values ​​output by the new energy power generation unit 11 (i.e., the voltage and / or current values ​​at point A1 in Figure 1), and the current and / or voltage values ​​output by the energy storage unit 12 (i.e., the voltage and / or current values ​​at point A5 in Figure 1). The signal acquisition unit can also be used to acquire the voltage and / or current values ​​output by the grid-connected power system 10. Devices for collecting current and / or voltage values ​​can be installed at the aforementioned points. For example, current transformers and / or voltage transformers can be installed at points A1, A3, A4, and A5. The current transformers are used to collect current values, and the voltage transformers are used to collect voltage values. During the control of the grid-connected power system 10, the current transformers and / or voltage transformers can intelligently and automatically collect current and / or voltage values ​​at corresponding locations when necessary, and transmit them to the signal acquisition unit, or to the control module, or via the signal acquisition module. The signal acquisition unit can use the current and / or voltage values ​​collected by the current transformer and / or voltage transformer at point A1 as the voltage and / or current values ​​output by the new energy power generation unit 11. The signal acquisition unit can also use the current and / or voltage values ​​collected by the current transformer and / or voltage transformer at point A3 as the voltage and / or current values ​​output by the grid-connected power system 10. The signal acquisition unit can use the current and / or voltage values ​​collected by the current transformer and / or voltage transformer at point A4 as the current and / or voltage values ​​at the grid connection point of the grid-connected power system 10. The signal acquisition unit can use the current and / or voltage values ​​collected by the current transformer and / or voltage transformer at point A5 as the current and / or voltage values ​​output by the energy storage unit 12.

[0045] In some embodiments, the new energy power generation unit may include power generation equipment and a converter. The power generation equipment is connected to one end of the converter, and the other end of the converter is connected to the power grid 21 via the power transmission line 13. The power generation equipment can convert new energy into electrical energy. The converter can be used to convert the electrical energy output by the power generation equipment into electrical energy that meets the requirements of the power transmission line 13. The power generation equipment may include, but is not limited to, one or more of the following: doubly-fed wind turbine, direct-drive wind turbine, semi-direct-drive wind turbine, squirrel-cage wind turbine, permanent magnet wind turbine, electrically excited wind turbine, horizontal axis wind turbine, vertical axis wind turbine, photovoltaic power generation unit, wind-solar integrated generator, and wind-solar-storage hybrid system. The photovoltaic power generation unit may include, but is not limited to, centralized photovoltaic units, string photovoltaic units, etc.

[0046] For example, Figure 2 is a schematic diagram of a grid-type power system provided in another embodiment of this application. As shown in Figure 2, the power generation equipment may include a doubly-fed wind turbine generator 113, and may also include an impeller 111 and a gearbox 112. The impeller 111 is connected to the gearbox 112, and the gearbox 112 is connected to the doubly-fed wind turbine generator 113. The stator of the doubly-fed wind turbine generator 113 may be connected to one end of a transformer 22, and the rotor of the doubly-fed wind turbine generator 113 is connected to a converter 115. The rotor of the doubly-fed wind turbine generator 113 is connected to one end of the transformer 22 through the converter 115, and the other end of the transformer 22 is connected to the power grid 21.

[0047] For example, Figure 3 is a structural schematic diagram of a grid-type power system provided in another embodiment of this application. As shown in Figure 3, the power generation equipment may include a semi-direct-drive wind turbine 114, and may also include an impeller 111 and a gearbox 112. The impeller 111 is connected to the gearbox 112, and the gearbox 112 is connected to the semi-direct-drive wind turbine 114. The output of the semi-direct-drive wind turbine 114 is connected to one end of a transformer 22, and the other end of the transformer 22 is connected to the power grid 21.

[0048] In some embodiments, the wind turbine in Figure 3 can also be a direct-drive wind turbine, in which case the gearbox 112 can be omitted and the direct-drive wind turbine is directly connected to the impeller 111.

[0049] The grid requirements in this embodiment may include ensuring the voltage and frequency stability of the power system. Specifically, the grid requirements may include the total current output by the grid-connected power system 10 being consistent with or approaching a reference value for the total current output by the grid-connected power system 10. For example, the difference between the total current output by the grid-connected power system 10 and the reference value for the total current output by the grid-connected power system 10 is within a preset difference range. The preset difference range can be set according to the scenario, requirements, experience, etc., and is not limited here. The reference value for the total current output by the grid-connected power system 10 can be obtained based on the amplitude and phase angle of the internal potential of the grid-connected power system 10. The energy storage converter 122 in the energy storage unit 12 is controlled according to this reference value to make the total current output by the grid-connected power system 10 consistent with or approaching a reference value for the total current output by the grid-connected power system 10. Figure 4 is a flowchart of a control method for a grid-type power system provided in an embodiment of this application. The control method for the grid-type power system is applied to the grid-type power system 10 in the above embodiment. As shown in Figure 4, the control method for the grid-type power system may include steps S301 to S303.

[0050] In step S301, the reference value of the total output current of the grid-type power system can be calculated based on the amplitude and phase angle of the internal potential of the grid-type power system.

[0051] The internal electromotive force (EMF) of a generator refers to the symmetrical three-phase EMF induced within the stator windings by the main magnetic field forming a rotating magnetic field in the air gap when the generator rotor rotates at synchronous speed, "cutting" the stator windings. Correspondingly, in this embodiment, the internal EMF of the grid-connected power system 10 refers to the symmetrical three-phase EMF induced in the entire grid-connected power system from the perspective of the grid side. The amplitude of the internal EMF of the grid-connected power system 10 can be obtained based on the reactive power parameters and / or the grid connection point voltage parameters of the grid-connected power system 10, as well as the grid connection point voltage reference value or the internal EMF reference value of the grid-connected power system 10. The reactive power parameters of the grid-connected power system 10 may include the reactive power reference value indicated by the reactive power command and the measured reactive power output value of the grid-connected power system 10. The grid connection point voltage parameters of the grid-connected power system 10 may include the target value of the grid connection point voltage and the measured value of the grid connection point voltage. The aforementioned measured reactive power value and measured grid connection point voltage value can be obtained from the data acquired by the signal acquisition unit.

[0052] The phase angle of the internal potential of the grid-connected power system 10 can be obtained based on the active power of the new energy generation unit 11, the active power of the grid-connected power system 10, and the active power reference value indicated by the active power command of the energy storage unit 12. The active power of the new energy generation unit 11 is the active power output by the new energy generation unit 11. The active power of the new energy generation unit 11 and the active power of the grid connection point can be obtained from the data acquired by the signal acquisition unit.

[0053] Based on the internal potential amplitude and internal potential phase angle of the grid-connected power system 10, combined with the voltage measurement value at the grid connection point and the virtual impedance parameters of the grid-connected power system 10, the total current reference value of the grid-connected power system 10 is obtained through coordinate system transformation, subtraction and other processing.

[0054] In step S302, the voltage setpoint of the energy storage unit is calculated based on the current value output by the new energy power generation unit, the current value output by the energy storage unit, and the total current reference value.

[0055] Based on the current values ​​output by the new energy power generation unit 11 and the energy storage unit 12, the total output current of the grid-connected power system 10 can be obtained. By processing the reference value of the total output current of the grid-connected power system 10 and the total output current of the grid-connected power system 10 through differential calculations and proportional resonance, the voltage setpoint of the energy storage unit 12 can be obtained.

[0056] In step S303, the switching transistor in the energy storage converter is controlled based on the voltage setpoint of the energy storage unit, thereby changing the magnitude of the output current of the energy storage unit so that the total output current of the grid-type power system meets the grid demand.

[0057] The voltage setpoint of the energy storage unit 12 can be processed using Pulse-Width Modulation Space Vector (PWMSV) to obtain a Pulse-Width Modulation (PWM) signal. This PWM signal is then used to control the energy storage converter 122, thereby controlling the energy storage unit 12. By controlling the switching transistors in the energy storage converter 122 using the PWM signal obtained based on the voltage setpoint of the energy storage unit 12, the magnitude of the output current of the energy storage unit 12 can be controlled, thereby controlling the total output current of the grid-connected power system 10. This ensures that the total output current of the grid-connected power system 10 is consistent with or approaches the reference value of the total output current of the grid-connected power system 10. Here, consistency or approaching consistency means that the difference between the total output current of the grid-connected power system 10 and the reference value of the total output current of the grid-connected power system 10 is within a preset difference range.

[0058] In this embodiment, the new energy power generation unit 11 is connected to the power grid 21 via a power transmission line, and the energy storage unit 12 is connected to the power transmission line 13 of the new energy power generation unit 11 to form a grid-connected power system 10. Based on the internal potential amplitude and phase angle of the grid-connected power system 10, a reference value for the total output current of the grid-connected power system 10 is calculated. Based on the current value output by the new energy power generation unit 11, the current value output by the energy storage unit 12, and the total current reference value, the voltage setpoint required to control the switching transistor in the energy storage converter 122 is obtained. The energy storage converter 122 is controlled according to this voltage setpoint, thereby controlling the magnitude of the output current of the energy storage unit 12, and ultimately controlling the total output current of the grid-connected power system 10 to meet the grid demand. This enables the grid-connected power system 10 to quickly and actively provide inertia support, improving the safety and stability of the power system.

[0059] In some embodiments, the internal potential amplitude can be calculated based on the reactive power command received by the grid-connected power system, the measured reactive power output of the grid-connected power system, and the grid connection point voltage reference value. The reactive power command received by the grid-connected power system can be a command issued by the power grid, specifically, the reactive power command issued by the power grid's Automatic Voltage Control (AVC) system. The reactive power command can characterize the reactive power reference value.

[0060] In some examples, a first difference is obtained between the reactive power command received by the grid-connected power system and the measured reactive power output of the grid-connected power system; a first voltage difference is obtained by performing a PI operation on the first difference; and the sum of the first voltage difference and the grid connection point voltage reference value is used as the internal potential amplitude of the grid-connected power system. For example, Figure 5 is a logical schematic diagram of an example of obtaining the internal potential amplitude provided by an embodiment of this application. As shown in Figure 5, the reactive power reference value represented by the reactive power command received by the grid-connected power system can be obtained first. Measured reactive power output of grid-connected power systems The first difference is then used to perform a proportional-integral (PI) operation to obtain the first voltage difference. This first voltage difference is then compared with the grid connection point voltage reference value E. B The summation is determined as the internal potential amplitude E. * In the example above, the reactive power reference value can also be obtained. Then, first check the reactive power reference value. Perform amplitude limiting processing, and then obtain the reactive power reference value after amplitude limiting processing. Measured reactive power output of grid-connected power systems The first voltage difference; after obtaining the first voltage difference, the first voltage difference can be limited, and the limited first voltage difference can be compared with the grid connection point voltage reference value E. B The summation is determined as the internal potential amplitude E. * .

[0061] In other examples, in response to a change in the grid connection point voltage measurement exceeding a preset threshold, a first difference can be obtained between the reactive power command received by the grid-connected power system and the measured reactive power output by the grid-connected power system. A PI calculation is performed on the first difference to obtain a first voltage difference, and the sum of the first voltage difference and the grid connection point voltage reference value is obtained. Based on the grid connection point voltage measurement and the internal potential reference value of the grid-connected power system, droop control is applied to the sum to obtain the internal potential amplitude of the grid-connected power system. A change in the grid connection point voltage measurement exceeding the preset threshold indicates a significant change in the grid connection point voltage measurement within a short period. By adding droop control, the dynamic response speed is accelerated, enabling the grid-connected power system to provide support to the power system more quickly, ensuring the stability and safety of the power system. For example, Figure 6 is a logical schematic diagram of another example of obtaining the internal potential amplitude provided by an embodiment of this application. As shown in Figure 6, the reactive power command is limited, which can be achieved by setting the maximum reactive power value Q. max and minimum reactive power Q min The reactive power reference value represented by the reactive power command after the limiting process is realized. It should be at the maximum reactive power Q max and minimum reactive power Q min Between; calculate the baseline value of reactive power Compared with the measured value of reactive power The first difference is obtained by performing a proportional-integral operation on the first difference; the first voltage difference can be limited by setting the maximum voltage difference U. max and the minimum voltage difference U min To achieve this, the first voltage difference after the limiting process should be within the maximum voltage difference U. max and the minimum voltage difference U min Between; calculate the first voltage difference after the limiting process and the grid connection point voltage reference value U. B The sum of U * ; Measurement value U of grid connection point voltage g Filtering is performed, as shown in Figure 6. This indicates filtering processing, and the sum U is calculated. * Compared with the filtered grid connection point voltage measurement value U g The difference is used to perform droop control on the difference to obtain a second voltage difference; the second voltage difference is then compared with the internal potential reference value E. iep The summation is determined as the internal potential amplitude E.* .

[0062] In other embodiments, the internal potential amplitude is calculated based on the target voltage value at the grid connection point of the grid-connected power system issued by the power grid dispatch center, the measured voltage value at the grid connection point, and the reference value of the internal potential of the grid-connected power system. For example, Figure 7 is a logical schematic diagram of another example of obtaining the internal potential amplitude provided by the embodiments of this application. As shown in Figure 7, the measured voltage value U at the grid connection point can be calculated. g Filtering is performed, as shown in Figure 7. This indicates filtering processing, calculating the target voltage U at the grid connection point of the grid-connected power system. * Compared with the filtered grid connection point voltage measurement value U g The difference is used to obtain the internal potential difference. This internal potential difference is then compared with the internal potential reference value E. iep The summation is determined as the internal potential amplitude E. * .

[0063] In other embodiments, the internal potential amplitude can be calculated based on the target voltage value at the grid connection point of the grid-connected power system issued by the power grid dispatch, the measured voltage value at the grid connection point, the measured reactive power output of the grid-connected power system, and the reference value of the internal potential of the grid-connected power system. For example, Figure 8 is a logical schematic diagram of another example of obtaining the internal potential amplitude provided by the embodiments of this application. As shown in Figure 8, the measured reactive power output of the grid-connected power system can be calculated... Filtering is performed, as shown in Figure 8. This indicates the filtered reactive power measurement value. Perform droop control to obtain the first voltage, and calculate the target voltage U at the grid connection point. * The second difference between the first voltage and the measured voltage U at the grid connection point g Perform filtering, calculate the second difference and the filtered grid connection point voltage measurement value U. g The third difference is then processed by proportional integration to obtain the internal potential difference. This internal potential difference is then compared with the internal potential reference value E. iep The sum of these values ​​is determined as the internal potential amplitude E. * .

[0064] In some embodiments, the internal potential phase angle can be calculated based on the active power of the new energy generation unit, the active power at the grid connection point of the grid-connected power system, and the active power command issued by the grid to the energy storage unit. The active power on the new energy generation unit side is the active power output by the new energy generation unit, which can be obtained from the data collected from point A1 in Figures 1 to 3. The data required to calculate the internal potential phase angle may also include internal potential phase calculation parameters, such as the angular frequency of the grid, virtual moment of inertia parameters, virtual damping coefficient, and the angular frequency of the internal potential of the grid-connected power system. The active power target value of the energy storage unit can be calculated based on the active power reference value represented by the active power on the new energy generation unit side and the active power command issued by the grid to the energy storage unit. Then, the internal potential phase angle can be calculated based on the active power target value and the active power at the grid connection point of the grid-connected power system. Specifically, the target active power value emitted by the energy storage unit can be calculated based on the active power at the new energy generation unit side and the active power command issued by the grid to the energy storage unit. Power synchronization control is then performed on the target active power value based on the active power at the grid connection point of the grid-connected power system to obtain the internal potential phase angle of the grid-connected power system. The active power command can be issued by the grid's Automatic Generation Control (AGC) system. The target active power value can be the sum of the active power at the new energy generation unit side and the active power reference value represented by the active power command issued by the grid to the energy storage unit, such as the active power target value P. set Active power P on the new energy power generation unit side source The active power reference value P, characterized by the active power command. cmd P can be satisfied set =P source +P cmd The active power on the new energy generation unit side can be calculated from the voltage value collected from the connection point between the energy storage unit and the power transmission line and the current value output by the new energy generation unit. Instantaneous power calculation methods or other power calculation methods can be used, and are not limited here. In some examples, the active power on the new energy generation unit side can be filtered to an appropriate degree before using the filtered active power on the new energy generation unit side to participate in the calculation of the active power target value. Power synchronization control can first perform a difference operation on the power data, and then combine it with the speed data to obtain the torque of the virtual rotating unit. The virtual rotating unit can be a virtual rotating unit in the simulated grid-type power system. The torque and moment of inertia parameters of the virtual rotating unit are used to obtain the speed of the virtual rotating unit. Then, the speed of the virtual rotating unit is used to obtain the angular frequency of the internal potential of the grid-type power system, and thus the phase angle of the internal potential.

[0065] For example, Figure 9 is a logical schematic diagram of an example of obtaining the internal potential phase angle provided by an embodiment of this application. As shown in Figure 9, the active power target value P of the energy storage unit is calculated. set With the active power P at the grid connection point g The difference is divided by the angular frequency ω of the potential within the grid-type power system to obtain the first torque value; the angular frequency of the power grid is then calculated. The difference in angular frequency ω between the internal potential and the angular frequency ω of the grid-type power system, and the product of the angular frequency difference and the virtual damping coefficient D, is the second torque value; the sum of the first torque value and the second torque value is calculated, and the sum of the torque values ​​is used as the torque of the virtual rotating unit; the acceleration of the virtual rotating unit is obtained through the torque of the virtual rotating unit and the virtual moment of inertia parameter J; the angular frequency ω of the internal potential of the grid-type power system is obtained through the acceleration of the virtual rotating unit and the Laplace operation (s in Figure 9 is the Laplace operator); the phase angle θ of the internal potential is obtained through the angular frequency ω of the internal potential of the grid-type power system and the Laplace operation.

[0066] After obtaining the internal potential amplitude and phase angle of the grid-connected power system in the above embodiments, a coordinate system transformation can be performed based on the internal potential amplitude and phase angle to obtain the voltage amplitude of the grid-connected power system in the two-phase stationary coordinate system. Combined with the voltage value obtained from the grid connection point voltage measurement in the two-phase stationary coordinate system, the total current reference value of the grid-connected power system in the two-phase stationary coordinate system can be obtained. The transformation between the three-phase stationary coordinate system and the two-phase stationary coordinate system can be achieved through Clark transformation or inverse Clark transformation, and the transformation between the two-phase stationary coordinate system and the two-phase rotating coordinate system can be achieved through Park transformation or inverse Park transformation.

[0067] For example, Figure 10 is a logic diagram of an example of obtaining a total current reference value provided by an embodiment of this application. As shown in Figure 10, based on the internal potential amplitude E * A coordinate system transformation is performed using the phase angle θ of the internal potential, converting it from a two-phase rotating coordinate system to a two-phase stationary coordinate system. and The voltage amplitude in the two-phase stationary coordinate system obtained by transformation. and L is the voltage in a two-phase stationary coordinate system obtained by converting the measured voltage value at the grid connection point. v s+R v For virtual impedance; calculate voltage amplitude. With voltage The difference can be considered as a voltage drop across the virtual impedance; it can be determined based on the voltage amplitude. With voltage The difference and virtual impedance L v s+R vThe first current value is obtained. Calculate voltage amplitude With voltage The difference can be considered as a voltage drop across the virtual impedance; it can be determined based on the voltage amplitude. With voltage The difference and virtual impedance L v s+R v The second current value is obtained. First current value Second current value The current in the two-phase stationary coordinate system is obtained by converting the total current reference value; the first current value can be... Second current value Convert to the total current reference value in a three-phase stationary coordinate system.

[0068] After obtaining the total current reference value, the measured total current output of the grid-connected power system can be acquired. Based on the total current reference value and the measured total current value, the voltage setpoint of the energy storage unit can be obtained. The measured total current value can be the sum of the current output of the new energy generation unit and the current output of the energy storage unit, or it can be directly collected from the output side of the grid-connected power system. The voltage setpoint can be obtained by performing subtraction calculations, proportional resonance calculations, and other operations on the total current reference value and the measured total current value.

[0069] The voltage setpoint can be obtained based on the total current reference value in a two-phase stationary coordinate system and the measured total current value in the same system. For example, Figure 11 is a logic diagram illustrating an example of obtaining the voltage setpoint according to an embodiment of this application. As shown in Figure 11, and I represents the reference total current value in a two-phase stationary coordinate system. α_s and I β_s The measured total current is the current value in a two-phase stationary coordinate system; calculate the current value. With current value I α_s The difference is used to perform proportional resonance to obtain the voltage value of the voltage setpoint in the two-phase stationary coordinate system. Calculate the current value With current value I β_s The difference is used to perform proportional resonance to obtain the voltage value of the voltage setpoint in the two-phase stationary coordinate system. According to voltage value and voltage value It can be converted to obtain the voltage setpoint in a three-phase stationary coordinate system.

[0070] The voltage setpoint can be obtained based on the total current reference value in a two-phase stationary coordinate system, the current value output by the new energy power generation unit in a two-phase stationary coordinate system, and the current value output by the energy storage unit in a two-phase stationary coordinate system. For example, Figure 12 is a logical schematic diagram of another example of obtaining the voltage setpoint provided in an embodiment of this application. As shown in Figure 12, and I represents the reference total current value in a two-phase stationary coordinate system. α_s1 and I β_s1 I represents the current output by the new energy power generation unit in a two-phase stationary coordinate system. α_Des and I β_Des The current value output by the energy storage unit is the current value in a two-phase stationary coordinate system; calculate the current value. and current value I α_s1 Current difference Calculate the current difference With current value I α_Des The difference is used to perform proportional resonance calculation to obtain the voltage value of the voltage setpoint in the two-phase stationary coordinate system. Calculate the current value and current value I β_s1 Current difference Calculate the current difference With current value I β_Des The difference is used to perform proportional resonance calculation to obtain the voltage value of the voltage setpoint in the two-phase stationary coordinate system.

[0071] A third aspect of this application provides a control device for a grid-type power system, which can be applied to the grid-type power system in the above embodiments. Figure 13 is a schematic diagram of the structure of a control device for a grid-type power system provided in an embodiment of this application. As shown in Figure 13, the control device 400 of the grid-type power system may include a reference current determination module 401, a voltage setpoint determination module 402, and a control module 403.

[0072] The reference current determination module 401 can be used to calculate the total current reference value of the grid-type power system output based on the internal potential amplitude and internal potential phase angle of the grid-type power system.

[0073] The voltage setpoint determination module 402 can be used to calculate the voltage setpoint of the energy storage unit based on the current value output by the new energy power generation unit, the current value output by the energy storage unit, and the total current reference value.

[0074] The control module 403 can be used to control the operation of the switching transistors in the energy storage converter based on the voltage setpoint of the energy storage unit, thereby changing the magnitude of the output current of the energy storage unit so that the total output current of the grid-connected power system meets the grid demand.

[0075] In some embodiments, the control device 400 of the grid-type power system may further include an internal potential amplitude determination module.

[0076] The internal potential amplitude determination module can be used to: calculate the internal potential amplitude based on the reactive power command received by the grid-connected power system, the measured reactive power output of the grid-connected power system, and the reference voltage value at the grid connection point; or, calculate the internal potential amplitude based on the target voltage value at the grid connection point and the measured voltage value at the grid connection point issued by the grid dispatch, and the reference internal potential value of the grid-connected power system; or, calculate the internal potential amplitude based on the target voltage value at the grid connection point, the measured voltage value at the grid connection point, the measured reactive power output of the grid-connected power system, and the reference internal potential value of the grid-connected power system issued by the grid dispatch.

[0077] In some examples, the internal potential amplitude determination module can be specifically used to: obtain the first difference between the reactive power command received by the grid-connected power system and the measured reactive power value output by the grid-connected power system; perform PI calculation on the first difference to obtain the first voltage difference; and use the sum of the first voltage difference and the grid connection point voltage reference value as the internal potential amplitude of the grid-connected power system.

[0078] In other examples, the internal potential amplitude determination module can also be specifically used to: in response to the change in the grid connection point voltage measurement value exceeding a preset threshold, perform droop control based on the grid connection point voltage measurement value, the internal potential reference value of the grid-connected power system, and the sum value to obtain the internal potential amplitude of the grid-connected power system.

[0079] In some embodiments, the control device 400 of the grid-type power system may further include an internal potential phase angle determination module.

[0080] The internal potential phase angle determination module can be used to calculate the internal potential phase angle based on the active power of the new energy power generation unit, the active power of the grid-connected power system, and the active power command issued by the grid to the energy storage unit.

[0081] In some examples, the internal potential phase angle determination module can be specifically used to: calculate the target value of active power issued by the energy storage unit based on the active power on the side of the new energy power generation unit and the active power command issued by the grid to the energy storage unit; and perform power synchronization control on the target value of active power based on the active power at the grid connection point of the grid-connected power system to obtain the internal potential phase angle of the grid-connected power system.

[0082] It should be noted that the control device 400 of the grid-type power system is a device corresponding to the control method of the grid-type power system described above. All implementation methods in the above method embodiments are applicable to the embodiments of this device and can achieve the same technical effect.

[0083] A fourth aspect of this application also provides a controller for a grid-type power system. Figure 14 is a schematic diagram of the structure of a controller for a grid-type power system provided in an embodiment of this application. As shown in Figure 14, the controller 500 of the grid-type power system includes a memory 501, a processor 502, and a computer program stored in the memory 501 and executable on the processor 502.

[0084] In some examples, the processor 502 described above may include a central processing unit (CPU), or an application-specific integrated circuit (ASIC), or one or more integrated circuits that may be configured to implement the embodiments of this application.

[0085] Memory 501 may include read-only memory (ROM), random access memory (RAM), disk storage media device, optical storage media device, flash memory device, electrical, optical, or other physical / tangible memory storage device. Therefore, typically, memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the control method of a grid-type power system according to embodiments of this application.

[0086] The processor 502 reads the executable program code stored in the memory 501 to run the computer program corresponding to the executable program code, so as to implement the control method of the grid-type power system in the above embodiment.

[0087] In some examples, the controller 500 of the grid-type power system may also include a communication interface 503 and a bus 504. As shown in Figure 14, the memory 501, processor 502, and communication interface 503 are connected via the bus 504 and communicate with each other.

[0088] The communication interface 503 is mainly used to enable communication between various modules, devices, units, and / or equipment in the embodiments of this application. Input devices and / or output devices can also be connected through the communication interface 503.

[0089] Bus 504 includes hardware, software, or both, that couples the components of controller 500 of a networked power system together. For example, and not limitingly, bus 504 may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a Hyper Transport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an Infinite Bandwidth Interconnect, a Low Pin Count (LPC) bus, a memory bus, a Micro Channel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-E) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local Bus (VLB) bus, or other suitable buses, or a combination of two or more of these. Where appropriate, bus 504 may include one or more buses. Although specific buses are described and illustrated in the embodiments of this application, this application considers any suitable bus or interconnection.

[0090] A fifth aspect of this application also provides a computer-readable storage medium storing computer program instructions. When executed by a processor, these computer program instructions can implement the control method of the grid-type power system in the above embodiments and achieve the same technical effect. To avoid repetition, further details are omitted here. The aforementioned computer-readable storage medium may include non-transitory computer-readable storage media, such as read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks, etc., and is not limited thereto.

[0091] This application provides a computer program product, which includes a computer program. When the computer program is executed by a processor, it implements the control method of the grid-type power system in the above embodiments and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0092] It should be clarified that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. For the device embodiments, controller embodiments, computer-readable storage medium embodiments, and computer program product embodiments, the relevant parts can be referred to the description section of the method embodiments. This application is not limited to the specific steps and structures described above and shown in the figures. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of this application. Furthermore, for the sake of brevity, detailed descriptions of known methods and techniques are omitted here.

[0093] The aspects of this application have been described above with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It should be understood that each block in the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that these instructions, executable via the processor of the computer or other programmable data processing apparatus, enable the implementation of the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field-programmable logic circuit. It is also understood that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can also be implemented by dedicated hardware performing the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

[0094] Those skilled in the art will understand that the above embodiments are exemplary and not restrictive. Different technical features appearing in different embodiments can be combined to achieve beneficial effects. Based on a study of the drawings, specification, and claims, those skilled in the art should be able to understand and implement other variations of the disclosed embodiments. In the claims, the term "comprising" does not exclude other means or steps; "article" without the use of a quantifier is intended to include one or more articles and can be used interchangeably with "one or more articles"; the terms "first" and "second" are used to identify names and not to indicate any particular order. Any reference numerals in the claims should not be construed as limiting the scope of protection. The functionality of multiple parts appearing in the claims can be implemented by a single hardware or software module. The appearance of certain technical features in different dependent claims does not mean that these technical features cannot be combined to achieve beneficial effects.

Claims

1. A grid-type power supply system, wherein, include: The new energy power generation unit is connected to the power grid through power transmission lines; An energy storage unit is connected to the power transmission line of the new energy power generation unit and connected to the power grid in parallel with the new energy power generation unit. The energy storage unit includes an energy storage converter, which is used to control the magnitude of the output current of the energy storage unit so that the total output current of the grid-type power system meets the grid demand.

2. The grid-type power supply system according to claim 1, wherein, The new energy power generation unit includes power generation equipment and a converter. The power generation equipment is connected to one end of the converter, and the other end of the converter is connected to the power grid through a power transmission line.

3. The grid-type power supply system according to claim 2, wherein, The power generation equipment includes at least one of the following: doubly-fed wind turbine, direct-drive wind turbine, semi-direct-drive wind turbine, squirrel-cage wind turbine, permanent magnet wind turbine, electrically excited wind turbine, horizontal axis wind turbine, vertical axis wind turbine, photovoltaic power generation unit, wind-solar integrated generator, and wind-solar-storage hybrid system.

4. The grid-type power supply system according to claim 1, wherein, It also includes: a signal acquisition unit, used to acquire the voltage and / or current values ​​at the grid connection point of the grid-connected power system, the voltage and / or current values ​​output by the new energy power generation unit, and the current and / or voltage values ​​output by the energy storage unit.

5. A control method for a grid-type power supply system, wherein, Applied to a grid-type power system as described in any one of claims 1 to 4, the method comprises: Calculate the reference value of the total output current of the grid-type power system based on the internal potential amplitude and internal potential phase angle of the grid-type power system. The voltage setpoint of the energy storage unit is calculated based on the current value output by the new energy power generation unit, the current value output by the energy storage unit, and the total current reference value. The switching transistors in the energy storage converter are controlled based on the voltage setpoint of the energy storage unit, thereby changing the magnitude of the output current of the energy storage unit so that the total output current of the grid-type power system meets the grid demand.

6. The control method for a grid-type power system according to claim 5, wherein, The internal potential amplitude is calculated based on the reactive power command received by the grid-connected power system, the measured reactive power output by the grid-connected power system, and the grid connection point voltage reference value. or, The internal potential amplitude is calculated based on the target voltage value at the grid connection point of the grid-connected power system issued by the power grid dispatch center, the measured voltage value at the grid connection point, and the reference value of the internal potential of the grid-connected power system. or, The internal potential amplitude is calculated based on the target voltage value at the grid connection point of the grid-connected power system issued by the power grid dispatch, the measured voltage value at the grid connection point, the measured reactive power output of the grid-connected power system, and the reference value of the internal potential of the grid-connected power system.

7. The control method for a grid-type power system according to claim 6, wherein, The internal potential amplitude is calculated based on the reactive power command received by the grid-connected power system, the measured reactive power output of the grid-connected power system, and the grid connection point voltage reference value, including: Obtain the first difference between the reactive power command received by the grid-connected power system and the measured reactive power output of the grid-connected power system; The first voltage difference is obtained by performing a PI operation on the first difference. The sum of the first voltage difference and the grid connection point voltage reference value is used as the internal potential amplitude of the grid-connected power system.

8. The control method for a grid-type power system according to claim 7, wherein, In response to the change in the measured voltage value at the grid connection point exceeding a preset threshold, the method further includes: Based on the measured voltage at the grid connection point, the reference value of the internal potential of the grid-connected power system, and the sum of the values, droop control is performed to obtain the internal potential amplitude of the grid-connected power system.

9. The control method for a grid-type power system according to claim 5, wherein, The internal potential phase angle is calculated based on the active power of the new energy power generation unit, the active power of the grid-connected power system, and the active power command issued by the grid to the energy storage unit.

10. The control method for a grid-type power system according to claim 9, wherein, The target value of active power issued by the energy storage unit is calculated based on the active power on the new energy power generation unit side and the active power command issued by the power grid to the energy storage unit. Based on the active power at the grid connection point of the grid-connected power system, power synchronization control is performed on the target value of the active power to obtain the internal potential phase angle of the grid-connected power system.

11. A control device for a grid-type power system, wherein, Applied to the grid-type power system as described in any one of claims 1 to 4; The device includes: The reference current determination module is used to calculate the reference value of the total output current of the grid-type power system based on the amplitude and phase angle of the internal potential of the grid-type power system. The voltage setpoint determination module is used to calculate the voltage setpoint of the energy storage unit based on the current value output by the new energy power generation unit, the current value output by the energy storage unit, and the total current reference value. The control module is used to control the operation of the switching transistors in the energy storage converter based on the voltage setpoint of the energy storage unit, thereby changing the magnitude of the output current of the energy storage unit so that the total output current of the grid-type power system meets the grid demand.

12. A controller for a grid-type power supply system, wherein, include: Processor and memory storing computer program instructions; When the processor executes the computer program instructions, it implements the control method for the grid-type power system as described in any one of claims 5 to 10.

13. A computer-readable storage medium, wherein, The computer-readable storage medium stores computer program instructions, which, when executed by a processor, implement the control method for a grid-type power system as described in any one of claims 5 to 10.

Images