Network construction type power supply system and control method and device thereof, controller and medium

Abstract

The invention discloses a network construction type power supply system, a control method and device thereof, a controller and a medium, and belongs to the technical field of electric power. The network construction type power supply system comprises a new energy power generation unit which is connected to a power grid through a power transmission line; and the energy storage unit is connected to a power outgoing line of the new energy power generation unit, is connected with the new energy power generation unit in parallel and then is connected to a power grid, the energy storage unit comprises an energy storage converter, and the energy storage converter is used for controlling the magnitude of the output current of the energy storage unit, so that the total current output by the network construction type power supply system meets the requirements of the power grid. According to the embodiment of the invention, the safety and stability of the power system can be improved.

Description

Technical Field

[0001] The present application belongs to the field of electric power technology, and in particular, relates to a grid-type power supply system and a control method, device, controller, and medium thereof. Background Art

[0002] With the continuous development of new energy technologies, new energy devices using new energy power generation technologies account for an increasing proportion in the power system. The characteristics of reverse distribution between new energy and power load equipment require new energy devices to transmit the generated electricity to the power grid over long distances through the AC and DC systems. The voltage in the power system is established by the power grid. The increase in the proportion of new energy devices in the power system has caused the power grid's ability to clamp the voltage at the grid connection point to continue to decline, resulting in low power grid strength and weak anti-interference ability of the power system, thus affecting the safety and stability of the power system. Summary of the invention

[0003] The embodiments of the present application provide a grid-type power supply system and a control method, device, controller, and medium thereof, which can improve the safety and stability of the power system.

[0004] In a first aspect, an embodiment of the present application provides a grid-type power supply system, comprising: a new energy power generation unit, connected to a power grid through a power transmission line; an energy storage unit, connected to the power transmission line of the new energy power generation unit, and connected to the power grid after being connected in parallel with the new energy power generation unit, the energy storage unit comprising an energy storage inverter, which is used to control the magnitude of the output current of the energy storage unit so that the total current output by the grid-type power supply system meets the needs of the power grid.

[0005] In some possible embodiments, the new energy power generation unit includes a power generation device and a converter, the power generation device is connected to one end of the converter, and the other end of the converter is connected to a power grid through a power transmission line.

[0006] In some possible embodiments, the power production equipment includes at least one of 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.

[0007] In some possible embodiments, the grid-type power supply system also includes: a signal acquisition unit, used to obtain the voltage value and / or current value of the grid-type power supply system grid connection point, the voltage value and / or current value output by the new energy power generation unit, and the current value and / or voltage value output by the energy storage unit.

[0008] In a second aspect, an embodiment of the present application provides a control method for a grid-type power supply system, which is applied to the grid-type power supply system of the first aspect, and the method comprises: calculating a total current reference value output by the grid-type power supply system based on an internal potential amplitude and an internal potential phase angle of the grid-type power supply system; calculating a voltage set value of the energy storage unit based on a current value output by a new energy power generation unit, a current value output by an energy storage unit, and a total current reference value; and controlling the operation of a switch tube in an energy storage inverter based on the voltage set value of the energy storage unit, thereby changing the size of the output current of the energy storage unit, so that the total current output by the grid-type power supply system meets the grid demand.

[0009] In some possible embodiments, the internal potential amplitude is calculated based on the reactive power instruction received by the grid-type power supply system, the actual measured value of the reactive power output by the grid-type power supply system and the grid-connected point voltage reference value; or, the internal potential amplitude is calculated based on the grid-connected point voltage target value and the grid-connected point voltage measurement value issued by the grid dispatcher, and the internal potential reference value of the grid-type power supply system; or, the internal potential amplitude is calculated based on the grid-connected point voltage target value and the grid-connected point voltage measurement value issued by the grid dispatcher, the actual measured value of the reactive power output by the grid-type power supply system and the internal potential reference value of the grid-type power supply system.

[0010] In some possible embodiments, the internal potential amplitude is calculated based on the reactive power command received by the grid-type power supply system, the actual measured reactive power value output by the grid-type power supply system and the grid-connected point voltage reference value, including: obtaining a first difference between the reactive power command received by the grid-type power supply system and the actual measured reactive power value output by the grid-type power supply 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-type power supply system.

[0011] In some possible embodiments, in response to a change in the grid-connected point voltage measurement value exceeding a preset threshold, the method further includes: performing droop control based on the grid-connected point voltage measurement value, a reference value of the internal potential of the grid-connected power system, and a sum value to obtain the internal potential amplitude of the grid-connected power system.

[0012] In some possible embodiments, the method further includes: calculating the internal potential phase angle based on the active power on the new energy power generation unit side, the active power of the grid-connected power system point, and the active power instruction sent by the power grid to the energy storage unit.

[0013] In some possible embodiments, the active power target value emitted by the energy storage unit is calculated based on the active power on the new energy power generation unit side and the active power instruction issued by the power grid to the energy storage unit; the active power target value is power-synchronized and controlled based on the active power of the grid-connected point of the grid-type power supply system to obtain the internal potential phase angle of the grid-type power supply system.

[0014] In a third aspect, an embodiment of the present application provides a control device for a grid-type power supply system, which is applied to the grid-type power supply system of the first aspect; the device includes: a reference current determination module, which is used to calculate a total current reference value output by the grid-type power supply system based on an internal potential amplitude and an internal potential phase angle of the grid-type power supply system; a voltage set value determination module, which is used to calculate a voltage set value of the energy storage unit based on a current value output by a new energy power generation unit, a current value output by an energy storage unit and a total current reference value; and a control module, which is used to control the operation of a switch tube in an energy storage inverter based on the voltage set value of the energy storage unit, thereby changing the size of the output current of the energy storage unit, so that the total current output by the grid-type power supply system meets the grid demand.

[0015] In a fourth aspect, an embodiment of the present application provides a controller for a grid-type power supply system, comprising: a processor and a memory storing computer program instructions; when the processor executes the computer program instructions, the control method for the grid-type power supply system of the second aspect is implemented.

[0016] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium having computer program instructions stored thereon, and when the computer program instructions are executed by a processor, the control method of the grid-type power supply system of the second aspect is implemented.

[0017] The embodiment of the present application provides a grid-type power supply system and its control method, device, controller, and medium. The new energy power generation unit is connected to the power grid through a power transmission line, and the energy storage unit is connected to the power transmission line of the new energy power generation unit to form a grid-type power supply system. The total current reference value output by the grid-type power supply system is calculated based on the internal potential amplitude and internal potential phase angle of the grid-type power supply system. The voltage set value required to control the switch tube in the energy storage converter is obtained 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 energy storage converter is controlled according to the voltage set value, thereby controlling the magnitude of the output current of the energy storage unit, and then controlling the total current output by the grid-type power supply system to meet the grid demand, so that the grid-type power supply system can quickly and actively provide inertia support, thereby improving the safety and stability of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solution of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0019] Figure 1 A schematic diagram of the structure of a grid-type power supply system provided in one embodiment of the present application; Figure 2A schematic diagram of the structure of a grid-type power supply system provided in another embodiment of the present application; Figure 3 A schematic diagram of the structure of a grid-type power supply system provided in another embodiment of the present application; Figure 4 A flow chart of a control method for a grid-type power supply system provided in one embodiment of the present application; Figure 5 A logic diagram of an example of obtaining the internal potential amplitude provided in an embodiment of the present application; Figure 6 A logic diagram of another example of obtaining the internal potential amplitude provided in an embodiment of the present application; Figure 7 A logic diagram of another example of obtaining the internal potential amplitude provided in an embodiment of the present application; Figure 8 A logic diagram of another example of obtaining the internal potential amplitude provided in an embodiment of the present application; Fig. 9 A logic diagram of an example of obtaining an internal potential phase angle provided in an embodiment of the present application; Fig.10 A logic diagram of an example of obtaining a total current reference value provided in an embodiment of the present application; Fig.11 A logic diagram of an example of obtaining a given voltage value provided in an embodiment of the present application; Fig.12 A logic diagram of another example of obtaining a given voltage value provided in an embodiment of the present application; Fig.13 A schematic diagram of the structure of a control device for a grid-type power supply system provided in one embodiment of the present application; Fig.14 A schematic diagram of the structure of a controller of a grid-type power supply system provided in one embodiment of the present application. DETAILED DESCRIPTION

[0020] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, rather than to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating the examples of the present application.

[0021] With the continuous development of new energy technologies, new energy devices using new energy power generation technologies account for an increasing proportion in the power system. The characteristics of reverse distribution between new energy and power load equipment require new energy devices to transmit the generated electricity to the power grid over long distances through the AC and DC systems. The voltage in the power system is established by the power grid. The increase in the proportion of new energy devices in the power system has caused the power grid's ability to clamp the voltage at the grid connection point to continue to decline, resulting in low grid strength and weak anti-interference capabilities of the power system. The power system will have various stability problems, among which voltage problems are particularly prominent, which seriously threaten the safe and stable operation of the power grid and various equipment in the power system.

[0022] The present application provides a grid-type power supply system and its control method, device, controller, and medium, which connects an energy storage unit to a power transmission line between a new energy power generation source and a power grid to form a grid-type power supply system. By controlling the grid-type power supply system, when a power grid fails, the grid-type power supply system can provide a larger short-circuit support current and reduce the scope of the fault. When a frequency disturbance occurs in the power system, it can quickly and actively provide power support, stabilize the frequency of the power system, and ensure the safety and stability of the power system.

[0023] The grid-type power supply system and its control method, device, controller, and medium provided in the present application are described below.

[0024] A first aspect of the present application provides a grid-type power supply system. Figure 1 A schematic diagram of the structure of a grid-type power supply system provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, the grid-type power supply system 10 may include a new energy power generation unit 11 and an energy storage unit 12 .

[0025] The new energy power generation unit 11 is connected to the power grid 21 through the power transmission line 13. The new energy power generation unit 11 can be implemented as a single new energy power generation device, multiple new energy power generation devices connected to a power transmission line 13, a new energy station, a new energy cluster formed by a mixed type of new energy stations, etc. 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, 220kV. Specifically, the new energy power generation unit 11 can be connected to the grid connection point A4 through the power transmission line 13, thereby being incorporated into the power grid 21.

[0026] The 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 after being connected in parallel with the new energy power generation unit 11. The energy storage unit 12 may include an energy storage device 121 and an energy storage converter 122. The energy storage device 121 can be connected to the power transmission line 13 through the energy storage converter 122, and A2 is the connection point between the energy storage converter 122 and the power transmission line 13. The energy storage device 121 may include but is not limited to batteries, flywheel devices, supercapacitors, etc., which are not limited here. The energy storage converter 122 may include a plurality of switch tubes, and the switch tubes may include but are not limited to switch tubes of the type of insulated gate bipolar transistor (IGBT). By controlling the energy storage converter 122, the current output by the energy storage device 121 to the power transmission line 13 can be controlled, that is, the output current of the 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 current output by the grid-type power supply system 10 meets the grid demand.

[0027] like Figure 1 As shown, point A2 is used to represent the connection point between the energy storage unit 12 and the power transmission line 13, and point A4 is used to represent the grid connection point of the grid-type power supply system 10. In some embodiments, the grid-type power supply system may also include a signal acquisition unit. The signal acquisition unit can be used to obtain the voltage value and / or current value (i.e., Figure 1 The voltage value and / or current value at point A4 in FIG. 1 ), the voltage value and / or current value output by the new energy power generation unit 11 (ie, Figure 1 The voltage value and / or current value at point A1 in FIG), and the current value and / or voltage value output by the energy storage unit 12 (ie, Figure 1The signal acquisition unit can also be used to obtain the voltage value and / or current value output by the grid-type power supply system 10. A device for collecting current values ​​and / or voltage values ​​can be set at the above-mentioned points. For example, a current transformer and / or a voltage transformer can be set at the above-mentioned points A1, A3, A4 and A5. The current transformer is used to collect current values, and the voltage transformer is used to collect voltage values. In the process of controlling the grid-type power supply system 10, when it is necessary to obtain the voltage value and / or current value at the corresponding position, the current transformer and / or the voltage transformer can intelligently and automatically collect the current value and / or the voltage value, and transmit it to the signal acquisition unit, or, it can be transmitted to the control module, or, it can be transmitted to the control module through the signal acquisition module. The signal acquisition unit can use the current value and / or voltage value collected by the current transformer and / or the voltage transformer at point A1 as the voltage value and / or current value output by the new energy power generation unit 11. The signal acquisition unit may use the current value and / or voltage value collected by the current transformer and / or voltage transformer at point A3 as the voltage value and / or current value output by the grid-type power supply system 10. The signal acquisition unit may use the current value and / or voltage value collected by the current transformer and / or voltage transformer at point A4 as the current value and / or voltage value of the grid-connected point of the grid-type power supply system 10. The signal acquisition unit may use the current value and / or voltage value collected by the current transformer and / or voltage transformer at point A5 as the current value and / or voltage value output by the energy storage unit 12.

[0028] In some embodiments, the new energy power generation unit may include power production equipment and a converter, the power production equipment is connected to one end of the converter, and the other end of the converter is connected to the power grid 21 through the power transmission line 13. The power production equipment is capable of converting new energy into electrical energy. The converter can be used to convert the electrical energy output by the power production equipment into electrical energy that meets the requirements of the power transmission line 13. The power production equipment may include but is not limited to a double-fed wind generator, a direct-drive wind generator, a semi-direct-drive wind generator, a squirrel-cage wind generator, a permanent magnet wind generator, an electrically excited wind generator, a horizontal axis wind generator, a vertical axis wind generator, a photovoltaic power generation unit, a wind-solar integrated generator, a wind-solar storage hybrid system, and one or more of the photovoltaic power generation unit may include but is not limited to a centralized photovoltaic unit, a string photovoltaic unit, etc., which are not limited here.

[0029] For example, Figure 2 A schematic diagram of the structure of a grid-type power supply system provided in another embodiment of the present application is shown in FIG. Figure 2As shown, the power generation equipment may include a doubly-fed wind generator 113, and may also include an impeller 111 and a gearbox 112, wherein the impeller 111 is connected to the gearbox 112, and the gearbox 112 is connected to the doubly-fed wind generator 113. The stator of the doubly-fed wind generator 113 may be connected to one end of the transformer 22, and the rotor of the doubly-fed wind generator 113 is connected to the converter 115, and the rotor of the doubly-fed wind 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.

[0030] For example, Figure 3 A schematic diagram of a grid-type power supply system provided in another embodiment of the present application is shown in FIG. Figure 3 As shown, the power generation equipment may include a semi-direct-drive wind turbine 114, and may also include an impeller 111 and a gearbox 112, wherein 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 a power grid 21.

[0031] In some embodiments, Figure 3 The wind turbine in the embodiment may also be a direct-drive wind turbine. In this case, the gear box 112 may be omitted, and the direct-drive wind turbine is directly connected to the impeller 111 .

[0032] The grid demand in the embodiment of the present application may include ensuring the voltage and frequency stability of the power system. Specifically, the grid demand may include that the total current output by the grid-type power supply system 10 is consistent with or tends to be consistent with the total current reference value output by the grid-type power supply system 10. For example, the difference between the total current output by the grid-type power supply system 10 and the total current reference value output by the grid-type power supply system 10 is within a preset difference range, and the preset difference range can be set according to the scene, demand, experience, etc., and is not limited here. The total current reference value output by the grid-type power supply system 10 can be obtained based on the internal potential amplitude and the internal potential phase angle of the grid-type power supply system 10, and the energy storage converter 122 in the energy storage unit 12 is controlled according to the total current reference value, so that the total current output by the grid-type power supply system 10 is consistent with or tends to be consistent with the total current reference value output by the grid-type power supply system 10. Figure 4 Flow chart of a control method of a grid-type power system provided in an embodiment of the present application. The control method of the grid-type power system is applied to the grid-type power system 10 in the above embodiment. Figure 4 As shown, the control method of the grid-type power supply system may include steps S301 to S303.

[0033] In step S301, a total current reference value output by the grid-type power supply system may be calculated based on the internal potential amplitude and the internal potential phase angle of the grid-type power supply system.

[0034] The internal electromotive force of the generator refers to the symmetrical three-phase electromotive force induced in the stator winding when the main magnetic field forms a rotating magnetic field in the air gap when the generator rotor rotates at a synchronous speed, "cutting" the stator winding. Correspondingly, in the embodiment of the present application, the internal potential of the grid-type power supply system 10 refers to the symmetrical three-phase electromotive force induced by the entire grid-type power supply system from the grid side. The internal potential amplitude of the grid-type power supply system 10 can be obtained based on the reactive power parameters of the grid-type power supply system 10 and / or the grid connection point voltage parameters of the grid-type power supply system 10, as well as the grid connection point voltage reference value of the grid-type power supply system 10 or the internal potential reference value of the grid-type power supply system 10. The reactive power parameters of the grid-type power supply system 10 may include the reactive power reference value indicated by the reactive power instruction and the reactive power measured value output by the grid-type power supply system 10. The grid connection point voltage parameters of the grid-type power supply system 10 may include the grid connection point voltage target value of the grid-type power supply system 10 and the grid connection point voltage measurement value of the grid-type power supply system 10. The above reactive power measured value and grid connection point voltage measurement value can be obtained through data acquired by the signal acquisition unit.

[0035] The internal potential phase angle of the grid-type power supply system 10 can be obtained based on the active power on the new energy power generation unit 11 side, the active power of the grid-type power supply system 10 grid connection point, and the active power reference value indicated by the active power instruction of the energy storage unit 12. The active power on the new energy power generation unit 11 side is the active power output by the new energy power generation unit 11. The above-mentioned active power on the new energy power generation unit 11 side and the active power of the grid connection point can be obtained through the data acquired by the signal acquisition unit.

[0036] Based on the internal potential amplitude and internal potential phase angle of the grid-type power supply system 10, combined with the voltage measurement value of the grid-connected point and the virtual impedance parameters of the grid-type power supply system 10, the total current reference value output by the grid-type power supply system 10 is obtained through coordinate system transformation, difference and other processing.

[0037] In step S302, a voltage reference value 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.

[0038] The total current output by the grid-type power supply system 10 can be obtained according to the current value output by the new energy power generation unit 11 and the current value output by the energy storage unit 12. The voltage given value of the energy storage unit 12 can be obtained by performing difference, proportional resonance and other processing on the total current reference value output by the grid-type power supply system 10 and the total current output by the grid-type power supply system 10.

[0039] In step S303, the switch tube in the energy storage converter is controlled to operate based on the voltage set value of the energy storage unit, thereby changing the magnitude of the output current of the energy storage unit so that the total current output by the grid-type power supply system meets the grid demand.

[0040] A pulse-width modulation space vector (PWMSV) process can be performed according to the voltage given value of the energy storage unit 12 to obtain a pulse-width modulation (PWM) signal, and the PWM signal is used to control the energy storage converter 122 to achieve control of the energy storage unit 12. By controlling the switch tube in the energy storage converter 122 based on the PWM signal obtained based on the voltage given value 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 current output by the grid-type power supply system 10, so that the total current output by the grid-type power supply system 10 is consistent with or tends to be consistent with the total current reference value output by the grid-type power supply system 10, and the consistency or tendency to be consistent here can refer to the difference between the total current output by the grid-type power supply system 10 and the total current reference value output by the grid-type power supply system 10 is within a preset difference range.

[0041] In the embodiment of the present application, the new energy power generation unit 11 is connected to the power grid 21 through the 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-type power supply system 10. The total current reference value output by the grid-type power supply system 10 is calculated based on the internal potential amplitude and internal potential phase angle of the grid-type power supply system 10, and the voltage set value required to control the switch tube in the energy storage converter 122 is obtained 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, and the energy storage converter 122 is controlled according to the voltage set value, so as to control the magnitude of the output current of the energy storage unit 12, and then control the total current output by the grid-type power supply system 10 to meet the grid demand, so that the grid-type power supply system 10 can quickly and actively provide inertia support, and improve the safety and stability of the power system.

[0042] In some embodiments, the internal potential amplitude can be calculated based on the reactive power instruction received by the grid-type power supply system, the measured reactive power value output by the grid-type power supply system, and the grid connection point voltage reference value. The reactive power instruction received by the grid-type power supply system can be an instruction issued by the power grid, specifically, the reactive power instruction issued by the automatic voltage reactive control (AVC) system of the power grid, and the reactive power instruction can represent the reactive power reference value.

[0043] In some examples, a first difference between a reactive power command received by a grid-type power supply system and a measured reactive power value output by the grid-type power supply system is obtained; a PI operation 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 used as the internal potential amplitude of the grid-type power supply system. For example, Figure 5 A logical schematic diagram of an example of obtaining the internal potential amplitude provided in an embodiment of the present application, such as Figure 5 As shown, the reactive power reference value represented by the reactive power instruction received by the grid-type power system can be obtained first. The measured value of reactive power output from the grid-type power supply system The first voltage difference is obtained by performing a proportional integral operation (PI operation) on the first difference, and the first voltage difference is compared with the grid connection point voltage reference value. The internal potential amplitude is determined by the sum of In the above example, the reactive power reference value can also be obtained Then, first calculate the reactive power reference value Perform amplitude limiting processing and then obtain the reactive power reference value after amplitude limiting processing The measured value of reactive power output from the grid-type power supply system After obtaining the first voltage difference, the first voltage difference may be limited, and the first voltage difference after the limiting process is compared with the grid connection point voltage reference value. The internal potential amplitude is determined by the sum of .

[0044] In other examples, in response to a change in the measured value of the grid connection point voltage exceeding a preset threshold, a first difference between the reactive power command received by the grid-connected power system and the measured value of the reactive power output by the grid-connected power system can be obtained; a PI operation 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 value and the grid-connected power system internal potential reference value, a droop control is performed on the sum to obtain the internal potential amplitude of the grid-connected power system. The change in the measured value of the grid connection point voltage exceeding the preset threshold indicates that the measured value of the grid connection point voltage has changed significantly in a short period of time. By adding droop control, the dynamic response speed is accelerated, so that the grid-connected power system can provide support to the power system more quickly and ensure the stability and safety of the power system. For example, Figure 6 A logical diagram of another example of obtaining the internal potential amplitude provided in an embodiment of the present application, such as Figure 6 As shown, the reactive power command is limited, and the limiting process can be performed by setting the maximum reactive power value. and reactive power minimum Realize the reactive power reference value represented by the reactive power instruction after limiting processing The reactive power should be at the maximum value and reactive power minimum Calculate reactive power reference value The measured value of reactive power The first voltage difference can be processed by setting a maximum voltage difference. Minimum voltage difference The first voltage difference after the limiting process should be within the maximum voltage difference value. Minimum voltage difference Calculate the first voltage difference after the limiting process and the grid connection point voltage reference value The sum of ;Measurement value of grid connection point voltage Perform filtering, Figure 6 In Indicates filtering processing, calculate the sum value The measured value of the grid connection point voltage after filtering The difference between the second voltage difference and the internal potential reference value is controlled to obtain a second voltage difference; the second voltage difference is compared with the internal potential reference value. The internal potential amplitude is determined by the sum of .

[0045] In other embodiments, the internal potential amplitude is calculated based on the grid-connected point voltage target value and grid-connected point voltage measurement value of the grid-connected power system issued by the grid dispatcher and the internal potential reference value of the grid-connected power system. Figure 7 A logical diagram of another example of obtaining the internal potential amplitude provided in the embodiment of the present application, such as Figure 7 As shown, the grid connection point voltage measurement value can be Perform filtering, Figure 7 In Indicates filtering processing and calculates the target voltage value of the grid-connected power system The measured value of the grid connection point voltage after filtering The difference is controlled to droop, and the internal potential difference is obtained, and the internal potential difference is compared with the internal potential reference value. The internal potential amplitude is determined by the sum of .

[0046] In some other embodiments, the internal potential amplitude can be calculated based on the grid-connected point voltage target value of the grid-connected power system issued by the grid dispatcher, the grid-connected point voltage measurement value, the measured value of the reactive power output of the grid-connected power system, and the internal potential reference value of the grid-connected power system. Figure 8 A logical diagram of another example of obtaining the internal potential amplitude provided in the embodiment of the present application, such as Figure 8 As shown, the reactive power measured value output by the grid-type power supply system can be To filter, Figure 8 In Indicates the filtering process, the measured value of reactive power after filtering Perform droop control, obtain the first voltage, and calculate the grid connection point voltage target value The second difference between the first voltage and the grid connection point voltage measurement value Filtering is performed to calculate the second difference and the measured value of the grid connection point voltage after filtering. The third difference is processed by proportional integration to obtain the internal potential difference, and the internal potential difference is compared with the internal potential reference value. The sum of the values ​​is determined as the internal potential amplitude .

[0047] In some embodiments, the internal potential phase angle can be 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 instruction sent by the power grid to the energy storage unit. The active power of the new energy power generation unit is the active power output by the new energy power generation unit, which can be obtained by Figures 1 to 3 The data collected from point A1 in the calculation of the internal potential phase angle may also include internal potential phase calculation parameters, such as the angular frequency of the power grid, the virtual moment of inertia parameter, the virtual damping coefficient, the angular frequency of the internal potential of the grid-type power system, etc. The active power target value of the energy storage unit can be calculated according to the active power on the new energy power generation unit side and the active power instruction issued by the power grid to the energy storage unit. Then, the internal potential phase angle can be calculated according to the active power target value and the active power of the grid-type power system grid connection point. Specifically, the active power target value issued by the energy storage unit can be calculated based on the active power on the new energy power generation unit side and the active power instruction issued by the power grid to the energy storage unit; the active power target value is controlled synchronously based on the active power of the grid-type power system grid connection point to obtain the internal potential phase angle of the grid-type power system. The active power instruction can be specifically issued by the automatic generation control (AGC) system of the power grid. The active power target value can be the sum of the active power of the new energy power generation unit and the active power reference value represented by the active power instruction sent by the power grid to the energy storage unit, such as the active power target value , Active power on the new energy power generation unit side and the active power reference value represented by the active power command Can satisfy . The active power on the new energy power generation unit side can be calculated by 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 power generation unit. The instantaneous power calculation method or other power calculation methods can be used, which are not limited here. In some examples, the active power on the new energy power generation unit side can be filtered to an appropriate degree first, and then the active power on the filtered new energy power generation unit side can be used to participate in the calculation of the active power target value. The power synchronization control can first perform a difference operation on the power data, and then obtain the torque of the virtual rotating unit together with the speed data. The virtual rotating unit can be a virtual rotating unit in the simulated grid-type power supply system; the torque and moment of inertia parameters of the virtual rotating unit are used to obtain the speed of the virtual rotating unit, and then the angular frequency of the internal potential of the grid-type power supply system is obtained through the speed of the virtual rotating unit, and then the internal potential phase angle is obtained.

[0048] For example, Fig. 9 A logic diagram of an example of obtaining the internal potential phase angle provided in an embodiment of the present application is as follows: Fig. 9 As shown, the active power target value of the energy storage unit is calculated Active power at the grid connection point The difference between the angular frequency of the potential in the grid-type power system Take the quotient and get the first torque value; calculate the angular frequency of the power grid The angular frequency of the potential in the grid-type power system The angular frequency difference, and the product of the angular frequency difference and the virtual damping coefficient D is the second torque value; the torque value and the value of the first torque value and the second torque value are calculated, and the torque value and the value are used as the torque of the virtual rotation unit; the torque of the virtual rotation unit and the virtual rotation inertia parameter are used to calculate the torque value and the virtual rotation inertia parameter. , get the acceleration of the virtual rotation unit; through the acceleration of the virtual rotation unit and Laplace operation ( Fig. 9 Where s is the Laplace operator), the angular frequency of the potential in the grid-type power system is obtained ; By constructing the angular frequency of the potential in the grid-type power system And Laplace operation, get the internal potential phase angle .

[0049] After obtaining the internal potential amplitude and internal potential phase angle of the grid-type power supply system in the above embodiment, the coordinate system conversion can be performed based on the internal potential amplitude and the internal potential phase angle to obtain the voltage amplitude of the grid-type power supply system in the two-phase stationary coordinate system, and combined with the voltage value in the two-phase stationary coordinate system obtained by converting the grid connection point voltage measurement value, the total current reference value of the grid-type power supply system in the two-phase stationary coordinate system is obtained. The conversion between the three-phase stationary coordinate system and the two-phase stationary coordinate system can be achieved through Clark transformation or Clark inverse transformation, and the conversion between the two-phase stationary coordinate system and the two-phase rotating coordinate system can be achieved through Park transformation or Park inverse transformation.

[0050] For example, Fig.10 A logic diagram of an example of obtaining a total current reference value provided in an embodiment of the present application, such as Fig.10 As shown, based on the internal potential amplitude and the internal potential phase angle Perform coordinate system transformation from a two-phase rotating coordinate system to a two-phase stationary coordinate system. and is the voltage amplitude in the two-phase stationary coordinate system obtained by conversion, and is the voltage in the two-phase stationary coordinate system obtained by converting the measured value of the grid-connected point voltage, is the virtual impedance; calculate the voltage amplitude With voltage The difference can be regarded as the voltage drop on the virtual impedance; the voltage amplitude can be With voltage The difference and virtual impedance , get the first current value ; Calculate voltage amplitude With voltage The difference can be regarded as the voltage drop on the virtual impedance; the voltage amplitude can be With voltage The difference and virtual impedance , get the second current value ; The first current value and the 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 and the second current value Converted into the total current reference value in the three-phase stationary coordinate system.

[0051] After obtaining the total current reference value, the total current measured value output by the grid-type power supply system can be obtained, and the voltage set value of the energy storage unit can be obtained according to the total current reference value and the total current measured value. The total current measured value can be the sum of the current value output by the new energy power generation unit and the current value output by the energy storage unit, or the total current measured value can be directly collected from the output side of the grid-type power supply system. The total current reference value and the total current measured value can be subjected to difference calculation, proportional resonance calculation and other operations to obtain the voltage set value.

[0052] The voltage set value can be obtained based on the current value of the total current reference value in the two-phase stationary coordinate system and the current value of the total current measured value in the two-phase stationary coordinate system. For example, Fig.11 A logic diagram of an example of obtaining a given voltage value provided in an embodiment of the present application is as follows: Fig.11 As shown, and is the current value of the total current reference value in the two-phase stationary coordinate system, and is the current value of the total current measured value in the two-phase stationary coordinate system; calculate the current value With current value The difference is proportionally resonated to obtain the voltage value of the voltage given value in the two-phase stationary coordinate system. ; Calculate the current value With current value The difference is proportionally resonated to obtain the voltage value of the voltage given value in the two-phase stationary coordinate system. ; According to the voltage value and voltage value The voltage given value in the three-phase stationary coordinate system can be converted.

[0053] The voltage set value can be obtained based on the current value of the total current reference value in the two-phase stationary coordinate system, the current value of the current value output by the new energy generation unit in the two-phase stationary coordinate system, and the current value of the current value output by the energy storage unit in the two-phase stationary coordinate system. For example, Fig.12 Another example of a logic diagram for obtaining a given voltage value provided in an embodiment of the present application is as follows: Fig.12 As shown, and is the current value of the total current reference value in the two-phase stationary coordinate system, and is the current value output by the new energy power generation unit in the two-phase stationary coordinate system, and The current value of the energy storage unit output in the two-phase stationary coordinate system; calculate the current value and current value The current difference , calculate the current difference With current value The difference is calculated by proportional resonance to obtain the voltage value of the voltage given value in the two-phase stationary coordinate system. ; Calculate the current value and current value The current difference , calculate the current difference With current value The difference is calculated by proportional resonance to obtain the voltage value of the voltage given value in the two-phase stationary coordinate system. .

[0054] A third aspect of the present application provides a control device for a grid-type power supply system, which can be applied to the grid-type power supply system in the above-mentioned embodiment. Fig.13 A schematic diagram of the structure of a control device for a grid-type power supply system provided in an embodiment of the present application is shown in FIG. Fig.13 As shown, the control device 400 of the grid-type power supply system may include a reference current determination module 401 , a voltage set value determination module 402 and a control module 403 .

[0055] The reference current determination module 401 may be used to calculate a total current reference value output by the grid-type power supply system based on an internal potential amplitude and an internal potential phase angle of the grid-type power supply system.

[0056] The voltage set value determination module 402 may be used to calculate the voltage set value 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.

[0057] The control module 403 can be used to control the operation of the switch tube in the energy storage converter based on the voltage set value of the energy storage unit, thereby changing the magnitude of the output current of the energy storage unit so that the total current output by the grid-type power supply system meets the grid demand.

[0058] In some embodiments, the control device 400 of the grid-type power supply system may further include an internal potential amplitude determination module.

[0059] 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-type power supply system, the actual measured value of the reactive power output by the grid-type power supply system and the grid-connected point voltage reference value; or, calculate the internal potential amplitude based on the grid-connected point voltage target value and the grid-connected point voltage measurement value issued by the power grid dispatcher, and the internal potential reference value of the grid-connected power supply system; or, calculate the internal potential amplitude based on the grid-connected point voltage target value and the grid-connected point voltage measurement value issued by the power grid dispatcher, the actual measured value of the reactive power output by the grid-connected power supply system and the internal potential reference value of the grid-connected power supply system.

[0060] In some examples, the internal potential amplitude determination module can be specifically used to: obtain a first difference between a reactive power command received by a grid-type power supply system and an actual measured value of reactive power output by the grid-type power supply system; perform a PI operation on the first difference to obtain a first voltage difference, and use the sum of the first voltage difference and a grid-connected point voltage reference value as the internal potential amplitude of the grid-type power supply system.

[0061] In other examples, the internal potential amplitude determination module can also be specifically used to: in response to a change in the grid-connected point voltage measurement value exceeding a preset threshold, perform droop control based on the grid-connected point voltage measurement value, the grid-type power supply system internal potential reference value and the sum value to obtain the internal potential amplitude of the grid-type power supply system.

[0062] In some embodiments, the control device 400 of the grid-type power supply system may further include an internal potential phase angle determination module.

[0063] The internal potential phase angle determination module can be used to calculate the internal potential phase angle based on the active power on the new energy power generation unit side, the active power of the grid-connected power system point, and the active power instruction sent by the power grid to the energy storage unit.

[0064] In some examples, the internal potential phase angle determination module can be specifically used to: calculate the active power target value emitted by the energy storage unit based on the active power on the new energy power generation unit side and the active power instruction issued by the power grid to the energy storage unit; perform power synchronization control on the active power target value based on the active power of the grid-connected point of the grid-type power supply system to obtain the internal potential phase angle of the grid-type power supply system.

[0065] It should be noted that the control device 400 of the grid-type power supply system is a device corresponding to the control method of the grid-type power supply system mentioned above, and all implementation methods in the above method embodiments are applicable to the embodiments of the device and can achieve the same technical effects.

[0066] The fourth aspect of the present application also provides a controller for a grid-type power supply system. Fig.14 A schematic diagram of the structure of a controller of a grid-type power supply system provided in an embodiment of the present application, such as Fig.14 As shown, the controller 500 of the grid-type power supply system includes a memory 501 , a processor 502 , and a computer program stored in the memory 501 and executable on the processor 502 .

[0067] In some examples, the processor 502 may include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application.

[0068] The memory 501 may include a read-only memory (ROM), a random access memory (RAM), a disk storage medium device, an optical storage medium device, a flash memory device, an electrical, optical or other physical / tangible memory storage device. Therefore, generally, the memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., a memory device) 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 the grid-type power supply system in the embodiment of the present application.

[0069] The processor 502 runs a computer program corresponding to the executable program code by reading the executable program code stored in the memory 501 , so as to implement the control method of the grid-type power supply system in the above-mentioned embodiment.

[0070] In some examples, the controller 500 of the grid-type power system may further include a communication interface 503 and a bus 504. Fig.14 As shown, the memory 501, the processor 502, and the communication interface 503 are connected via a bus 504 and communicate with each other.

[0071] The communication interface 503 is mainly used to realize the communication between the modules, devices, units and / or equipment in the embodiment of the present application. The communication interface 503 can also be used to access input devices and / or output devices.

[0072] The bus 504 includes hardware, software, or both, coupling the components of the controller 500 of the grid-type power system to each other. By way of example and not limitation, the 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 InfiniBand 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 the above. Where appropriate, the bus 504 may include one or more buses. Although embodiments of the present application describe and illustrate a particular bus, the present application contemplates any suitable bus or interconnect.

[0073] The fifth aspect of the present application also provides a computer-readable storage medium, on which computer program instructions are stored. When the computer program instructions are executed by the processor, the control method of the grid-type power supply system in the above embodiment can be implemented, and the same technical effect can be achieved. In order to avoid repetition, it will not be repeated here. Among them, the above-mentioned computer-readable storage medium may include a non-transitory computer-readable storage medium, such as a read-only memory (Read-Only Memory, referred to as ROM), a random access memory (Random Access Memory, referred to as RAM), a disk or an optical disk, etc., which is not limited here.

[0074] The present 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 supply system in the above-mentioned embodiment and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0075] It should be clear 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 each other, and each embodiment focuses on the differences from other embodiments. For device embodiments, controller embodiments, computer-readable storage medium embodiments, and computer program product embodiments, the relevant parts can refer to the description part of the method embodiment. The present 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 between the steps after understanding the spirit of the present application. In addition, for the sake of brevity, a detailed description of known method technologies is omitted here.

[0076] The above describes various aspects of the present application with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present application. It should be understood that each box in the flowchart and / or block diagram and the combination of each box in the flowchart and / or block diagram 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 device to produce a machine so that these instructions executed by the processor of the computer or other programmable data processing device enable the implementation of the functions / actions specified in one or more boxes of the flowchart and / or block diagram. 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 can also be understood that each box in the block diagram and / or flowchart and the combination of boxes in the block diagram and / or flowchart can also be implemented by dedicated hardware that performs a specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0077] Those skilled in the art should understand that the above embodiments are exemplary rather than restrictive. Different technical features appearing in different embodiments can be combined to achieve beneficial effects. Based on the study of the drawings, the specification and the 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 devices or steps; the quantifier "one" does not exclude multiple; the terms "first" and "second" are used to indicate names rather than to indicate any specific order. Any figure marks in the claims should not be understood as limiting the scope of protection. The functions 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, It is characterized in that include: The renewable energy power generation unit is connected to the power grid through the power transmission line; The energy storage unit is connected to the power transmission line of 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. The energy storage unit includes an energy storage inverter, and the energy storage inverter is used to control the output current of the energy storage unit so that the total current output by the grid-type power supply system meets the power grid demand.

2. The grid-type power supply system according to claim 1, It is characterized in that 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 a power grid through a power transmission line.

3. The grid-type power supply system according to claim 2, It is characterized in that The power production equipment includes at least one of 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 system.

4. The grid-type power supply system according to claim 1, It is characterized in that Also includes: The signal acquisition unit is used to obtain the voltage value and / or current value of the grid-connected point of the grid-connected power supply system, the voltage value and / or current value output by the new energy power generation unit, and the current value and / or voltage value output by the energy storage unit.

5. A control method for a grid-type power supply system, It is characterized in that Applied to the grid-type power supply system according to any one of claims 1 to 4, the method comprises: Calculate a total current reference value output by the grid-type power supply system based on the internal potential amplitude and the internal potential phase angle of the grid-type power supply system; Calculating a 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 switch tube in the energy storage converter is controlled to operate based on the voltage set value of the energy storage unit, thereby changing the magnitude of the output current of the energy storage unit so that the total current output by the grid-type power supply system meets the grid demand.

6. The control method of the grid-type power supply system according to claim 5, It is characterized in that The internal potential amplitude is calculated based on the reactive power command received by the grid-type power supply system, the measured reactive power value output by the grid-type power supply system and the grid connection point voltage reference value; or, The internal potential amplitude is calculated based on the grid-connected point voltage target value and the grid-connected point voltage measurement value of the grid-connected power system issued by the power grid dispatcher and the internal potential reference value of the grid-connected power system; or, The internal potential amplitude is calculated based on the grid-connected point voltage target value issued by the power grid dispatch, the grid-connected point voltage measurement value, the actual measured value of the reactive power output by the grid-connected power system and the internal potential reference value of the grid-connected power system.

7. The control method of the grid-type power supply system according to claim 6, It is characterized in that The internal potential amplitude is calculated based on the reactive power command received by the grid-forming power system, the measured reactive power value output by the grid-forming power system and the grid connection point voltage reference value, including: Obtaining a first difference between a reactive power command received by the grid-forming power supply system and a reactive power measured value output by the grid-forming power supply system; A PI operation is performed on the first difference to obtain a first voltage difference, and a sum of the first voltage difference and the grid-connected point voltage reference value is used as the internal potential amplitude of the grid-type power supply system.

8. The control method of the grid-type power supply system according to claim 7, It is characterized in that In response to the grid connection point voltage measurement value changing beyond a preset threshold, the method further includes: Droop control is performed based on the grid connection point voltage measurement value, the internal potential reference value of the grid-type power supply system and the sum value to obtain the internal potential amplitude of the grid-type power supply system.

9. The control method of the grid-type power supply system according to claim 5, It is characterized in that The internal potential phase angle is calculated based on the active power on the new energy power generation unit side, the active power of the grid-connected power system point, and the active power instruction sent by the power grid to the energy storage unit.

10. The control method of the grid-type power supply system according to claim 9, It is characterized in that Calculate the active power target value emitted by the energy storage unit based on the active power of the new energy power generation unit and the active power instruction issued by the power grid to the energy storage unit; The active power target value is subjected to power synchronization control based on the active power of the grid-connected point of the grid-forming power supply system to obtain the internal potential phase angle of the grid-forming power supply system.

11. A control device for a grid-type power supply system, It is characterized in that Applicable to a grid-type power supply system as claimed in any one of claims 1 to 4; The device comprises: A reference current determination module, used to calculate a total current reference value output by the grid-type power supply system based on an internal potential amplitude and an internal potential phase angle of the grid-type power supply system; A voltage set value determination module, used to calculate the voltage set value 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; A control module is used to control the operation of the switch tube in the energy storage converter based on the voltage set value of the energy storage unit, thereby changing the magnitude of the output current of the energy storage unit so that the total current output by the grid-type power supply system meets the grid demand.

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

13. A computer-readable storage medium, It is characterized in that The computer-readable storage medium stores computer program instructions, and when the computer program instructions are executed by the processor, the control method of the grid-type power supply system as described in any one of claims 5 to 10 is implemented.

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