Method for controlling an electrical energy router and electrical energy router
By acquiring and iteratively processing real-time voltage and power data from the power router, and calculating and correcting the droop curve, the problems of power mutual assistance and DC mutual assistance bus voltage regulation between multiple transformer areas were solved, thus realizing local photovoltaic consumption and voltage stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- STATE GRID HEBEI ELECTRIC POWER CO LTD
- Filing Date
- 2022-06-30
- Publication Date
- 2026-04-17
AI Technical Summary
Existing power router control methods cannot achieve power exchange between multiple transformer substations, cannot better enable local or nearby photovoltaic power consumption, and cannot achieve error-free regulation of DC exchange bus voltage.
By acquiring the real-time voltage of the DC mutual support bus and the total photovoltaic power generation and the total DC and AC load power of the distribution area, the surplus and deficit power of the distribution area is calculated, the droop curve is determined, and iterative processing is performed after a preset time to correct the droop curve, so as to realize the power mutual support between power routers and the errorless regulation of the DC mutual support bus voltage.
It enables power exchange between multiple transformer substations, improves the local or nearby photovoltaic absorption efficiency, and achieves stable regulation of DC exchange bus voltage.
Smart Images
Figure CN115276085B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of power control technology for power system microgrids, specifically to a power router control method and a power router. Background Technology
[0002] An Electrical Energy Router (EER) is a device that enables multidirectional energy flow and active control of power flow. Currently, EERs are typically used in single distribution networks or microgrids.
[0003] Existing power router control methods typically only consider the control of a single power router, with little research on the interconnection of multiple power routers across distribution areas. In other words, existing power router control methods cannot achieve power mutual assistance between multiple distribution areas, cannot better enable photovoltaic power to be consumed locally or nearby and must be directly fed back to the grid, and also cannot achieve error-free regulation of the DC mutual assistance bus voltage. Summary of the Invention
[0004] To overcome the problems existing in related technologies, this application provides a power router control method and a power router.
[0005] This application is achieved through the following technical solution:
[0006] In a first aspect, embodiments of this application provide a power router control method. This method is applied to multiple power routers, each corresponding to a different transformer substation. The power router control method includes: acquiring the first real-time voltage of the DC mutual support bus, the total photovoltaic power generation of the transformer substation, and the total DC / AC load power of the transformer substation; calculating the transformer substation surplus / deficit power based on the total photovoltaic power generation and the total DC / AC load power of the transformer substation; determining a droop curve based on the first real-time voltage and the transformer substation surplus / deficit power, so that the power router absorbs power from or supplies power to the DC mutual support bus according to the droop curve; after a preset time, acquiring the second real-time voltage of the DC mutual support bus; iteratively processing the transformer substation surplus / deficit power based on the second real-time voltage and the rated voltage of the DC mutual support bus to obtain a corrected transformer substation surplus / deficit power; and correcting the droop curve based on the corrected transformer substation surplus / deficit power, so that the power router absorbs power from or supplies power to the DC mutual support bus according to the corrected droop curve.
[0007] In one possible implementation of the first aspect, the substation's profit / loss power is calculated based on the total photovoltaic power generation and the total DC / AC load power of the substation, and a droop curve is determined based on the first real-time voltage and the substation's profit / loss power, including: calculating the difference between the total photovoltaic power generation and the total DC / AC load power of the substation as the substation's profit / loss power; determining the substation category based on the substation's profit / loss power, wherein the substation category includes substations with deficits and substations with surpluses; and determining the droop curve based on the first real-time voltage and the substation category.
[0008] In one possible implementation of the first aspect, determining the transformer area category based on the transformer area's profit and loss power includes: if the transformer area's profit and loss power is less than 0, then determining the transformer area as a deficit transformer area; if the transformer area's profit and loss power is greater than 0, then determining the transformer area as a surplus transformer area.
[0009] In one possible implementation of the first aspect, determining the droop curve based on the first real-time voltage and the transformer area category includes: if the transformer area is a subsidized transformer area, then determining the droop curve according to a first formula, the first formula being: P = k * (V dcn -V dc If the first real-time voltage is less than the rated voltage and the distribution area is a surplus distribution area, then the droop curve is determined according to the second formula, which is: P = k * (V dcn -V dc )+ΔP; where P is the power supplied to or absorbed from the DC mutual support bus, V dcn The rated voltage, V dc ΔP represents the first real-time voltage, k is the droop curve coefficient, and ΔP is the power surplus / deficit of the transformer area.
[0010] In one possible implementation of the first aspect, the power deficit of the distribution area is iteratively processed based on the second real-time voltage and the rated voltage of the DC mutual assistance bus to obtain the corrected power deficit of the distribution area, and the droop curve is corrected according to the corrected power deficit of the distribution area, including: if the second real-time voltage is less than the rated voltage and the distribution area is a deficit area, or if the second real-time voltage is greater than the rated voltage and the distribution area is a surplus area, then the power deficit of the distribution area is iteratively processed to obtain the corrected power deficit of the distribution area, and the droop curve is corrected according to the corrected power deficit of the distribution area.
[0011] In one possible implementation of the first aspect, the power router control method further includes: after each iteration of the iterative processing, obtaining the surplus or deficit power of the iterative transformer area, correcting the droop curve according to the surplus or deficit power of the iterative transformer area, so that the power router absorbs power from or transmits power to the DC mutual support bus according to the droop curve after iteration, and re-acquires the second real-time voltage for the next iteration, until the iteration stop condition is met.
[0012] In one possible implementation of the first aspect, the power router control method further includes: if the second real-time voltage is less than the rated voltage and the distribution area is a surplus distribution area, or if the second real-time voltage is greater than the rated voltage and the distribution area is a deficit distribution area, then no iterative processing is performed on the surplus or deficit power of the distribution area.
[0013] In a second aspect, embodiments of this application provide a power router for executing the power router control method as described in any of the first aspects; the power router includes: an interconnection port for connecting to a DC mutual support bus and detecting the real-time voltage of the DC mutual support bus; a photovoltaic port for connecting to distributed photovoltaic systems and detecting the total photovoltaic power generation of the distributed photovoltaic system; a DC load port for supplying power to the DC loads in the distribution area and detecting the total DC load power in the distribution area; and an AC load port for supplying power to the AC loads in the distribution area and detecting the total AC load power in the distribution area.
[0014] In one possible implementation of the second aspect, the power router further includes: a grid connection port for connecting to the low-voltage side of the AC transformer on the AC bus; and an energy storage port for connecting to an energy storage system.
[0015] In one possible implementation of the second aspect, the interconnection port includes a converter for detecting the real-time voltage of the DC mutual support bus and supplying or absorbing power from the DC mutual support bus; the converter includes a controller for calculating the substation's surplus / deficit power based on the total photovoltaic power generation and the total DC / AC load power of the substation, and determining a droop curve based on a first real-time voltage and the substation's surplus / deficit power; the controller is also used to iteratively process the substation's surplus / deficit power based on a second real-time voltage and the rated voltage of the DC mutual support bus to obtain a corrected substation surplus / deficit power, and correct the droop curve based on the corrected substation surplus / deficit power.
[0016] It is understandable that the beneficial effects of the second aspect mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here.
[0017] The power router control method and power router provided in this application embodiment acquire the first real-time voltage of the DC mutual support bus, the total photovoltaic power generation of the transformer area, and the total DC and AC load power of the transformer area. Based on the total photovoltaic power generation and the total DC and AC load power of the transformer area, the power surplus / deficit power of the transformer area is calculated. A droop curve is determined based on the first real-time voltage and the power surplus / deficit power of the transformer area. This allows the power router to absorb power from or supply power to the DC mutual support bus according to the droop curve. After a preset time, the second real-time voltage of the DC mutual support bus is acquired. Based on the second real-time voltage and the rated voltage of the DC mutual support bus, the power surplus / deficit power of the transformer area is iteratively processed to obtain a corrected power surplus / deficit power and a corrected droop curve. This allows the power router to absorb power from or supply power to the DC mutual support bus according to the corrected droop curve. This enables power mutual support between multiple transformer areas, better local or nearby photovoltaic power consumption, and error-free regulation of the DC mutual support bus voltage.
[0018] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this specification. Attached Figure Description
[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0020] Figure 1 This is a schematic diagram of the structure of a power router and a connection diagram of multiple power routers provided in an embodiment of this application;
[0021] Figure 2 This is a schematic flowchart of a power router control method provided in an embodiment of this application;
[0022] Figure 3 This is a schematic diagram illustrating the control principle of a drooping curve provided in an embodiment of this application;
[0023] Figure 4 This is a schematic flowchart of a power router control method provided in an embodiment of this application;
[0024] Figure 5 This is a schematic diagram of adjusting the droop curve according to an embodiment of this application;
[0025] Figure 6 This is a schematic diagram illustrating the adjustment of the sag curve of multiple zones provided in an embodiment of this application;
[0026] Figure 7This is a schematic flowchart of an iterative process provided in an embodiment of this application;
[0027] Figure 8 This is a schematic flowchart of an iterative process provided in an embodiment of this application;
[0028] Figure 9 This is a schematic diagram illustrating the adjustment of the sag curve of multiple zones provided in an embodiment of this application. Detailed Implementation
[0029] The present application will be described more clearly below with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the function of the present application, but do not limit the present application in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present application. These all fall within the protection scope of the present application.
[0030] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.
[0031] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.
[0032] In the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0033] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.
[0034] Furthermore, the term "multiple" mentioned in the embodiments of this application should be interpreted as two or more.
[0035] An Electrical Energy Router (EER) is a device that enables multi-directional energy flow and active control of power flow. Currently, EERs are typically used in single distribution networks or microgrids. Existing EER control methods usually only consider the control of a single EER, with little research on the interconnection of multiple EERs across different distribution areas. In other words, when a distribution area has a power surplus, the corresponding EER will typically feed the excess power back to the grid, rather than interconnecting with adjacent distribution areas, thus failing to achieve power sharing between two or more distribution areas.
[0036] Existing power router control methods cannot achieve power exchange between multiple distribution areas, cannot better enable local or nearby photovoltaic power consumption and must be directly fed back to the grid, and also cannot achieve error-free regulation of the DC mutual assistance bus. In addition, existing power routers have a limited number of ports and cannot simultaneously connect power routers of microgrid elements such as distribution networks, photovoltaic equipment, energy storage equipment, AC and DC loads, as well as adjacent microgrids.
[0037] Based on the above problems, the inventors discovered that, without relying on communication between different transformer substations, the droop curve of each power router can be adjusted by detecting the real-time voltage of the DC mutual support bus. This allows each power router to absorb power from or transmit power to the DC mutual support bus according to the droop curve, thereby achieving power mutual support between multiple transformer substations.
[0038] In other words, this embodiment of the application obtains the first real-time voltage of the DC mutual support bus, the total photovoltaic power generation of the transformer area, and the total DC and AC load power of the transformer area. It calculates the transformer area's surplus / deficit power based on the total photovoltaic power generation and the total DC and AC load power of the transformer area, and determines the droop curve based on the first real-time voltage and the transformer area's surplus / deficit power. This allows the power router to absorb power from or transmit power to the DC mutual support bus according to the droop curve. After a preset time, the second real-time voltage of the DC mutual support bus is obtained. Based on the second real-time voltage and the rated voltage of the DC mutual support bus, the transformer area's surplus / deficit power is iteratively processed to obtain the corrected transformer area surplus / deficit power and correct the droop curve. This allows the power router to absorb power from or transmit power to the DC mutual support bus according to the corrected droop curve. This enables power mutual support between multiple transformer areas, better local or nearby photovoltaic power consumption, and error-free regulation of the DC mutual support bus voltage.
[0039] Figure 1 This is a structural schematic diagram of a power router provided in one embodiment of this application, and a connection schematic diagram of multiple power routers. For example... Figure 1 As shown, the power router 10 is used to execute the power router control method. The power router 10 includes: an interconnect port 11, a photovoltaic port 12, a DC load port 13, and an AC load port 14.
[0040] Interconnection port 11 is used to connect to the DC mutual support bus and detect the real-time voltage of the DC mutual support bus. Photovoltaic port 12 is used to connect distributed photovoltaic (PV) systems and detect the total power generation of the distributed PV system in the area. DC load port 13 is used to supply power to the DC loads in the area and detect the total power of the DC loads in the area. AC load port 14 is used to supply power to the AC loads in the area and detect the total power of the AC loads in the area.
[0041] The above-mentioned power router control method can be any power router control method provided in any embodiment of this application.
[0042] Optionally, the DC power exchange bus can be a 750V DC bus. Interconnection port 11 can be a dual active bridge (DAB) converter, used to connect the power router 10 to the DC power exchange bus for power exchange with power routers 10 in other distribution areas. Photovoltaic port 12 can be a Boost converter, also used to connect to the internal DC bus of the power router 10. DC load port 13 can be a Buck circuit, and AC load port 14 can be a three-phase full-bridge inverter circuit.
[0043] Specifically, interconnection port 11 may include a converter (not shown). This converter is used to detect the real-time voltage of the DC interconnection bus and to supply power to or absorb power from the DC interconnection bus.
[0044] Optionally, the converter described above may include a controller (not shown). The controller is used to calculate the power deficit of the distribution area based on the total photovoltaic power generation and the total DC and AC load power of the distribution area, and to determine the droop curve based on the first real-time voltage and the power deficit of the distribution area.
[0045] For example, the controller is also used to iteratively process the power surplus / deficit of the transformer area based on the second real-time voltage and the rated voltage of the DC mutual assistance bus to obtain the corrected power surplus / deficit of the transformer area, and correct the droop curve based on the corrected power surplus / deficit of the transformer area.
[0046] Optionally, the power router 10 also includes a grid connection port 15 and an energy storage port 16. The grid connection port 15 is used to connect to the low-voltage side of the AC transformer on the AC bus. The energy storage port 16 is used to connect to an energy storage system.
[0047] For example, grid connection port 15 can be a dual active bridge converter, and the low-voltage side of the AC transformer on the AC bus can be an AC transformer for a 380V AC bus. Energy storage port 16 can be an LCLC bidirectional DC-DC converter, used to connect a hybrid energy storage system consisting of batteries and supercapacitors to store surplus power in the distribution area.
[0048] The power router provided in this application embodiment is equipped with an interconnection port for connecting to the DC mutual support bus and detecting the real-time voltage of the DC mutual support bus, a photovoltaic port for connecting distributed photovoltaics and detecting the total photovoltaic power generation of the distributed photovoltaic area, a DC load port for supplying power to the DC loads of the area and detecting the total DC load power of the area, an AC load port for supplying power to the AC loads of the area and detecting the total AC load power of the area, a grid connection port for connecting to the low-voltage side of the AC transformer of the AC bus, and an energy storage port for connecting to the energy storage system. It can simultaneously connect microgrid elements such as distribution network, photovoltaic equipment, energy storage equipment, AC and DC loads, and the DC mutual support bus, thereby realizing power mutual support between multiple areas, better realizing local or nearby photovoltaic consumption, and realizing error-free regulation of the DC mutual support bus voltage.
[0049] Figure 2 This is a flowchart illustrating a power router control method provided in an embodiment of this application. Figure 2 As shown, the method in the embodiments of this application may include:
[0050] Step 101: Obtain the first real-time voltage of the DC mutual support bus, the total photovoltaic power generation of the transformer area, and the total DC and AC load power of the transformer area.
[0051] Optionally, the DC mutual support bus can be a 750V DC bus. The total DC and AC load power of the transformer area includes the total DC load power and the total AC load power of the transformer area. The power router can directly detect the first real-time voltage of the DC mutual support bus, the total photovoltaic power generation of the transformer area, the total DC load power of the transformer area, and the total AC load power of the transformer area. Among them, the sum of the total DC load power and the total AC load power of the transformer area is the total DC and AC load power of the transformer area.
[0052] It should be noted that the total power of the AC load in the above-mentioned transformer area is the total power of some unconventional loads in the transformer area, such as frequency converter loads with a frequency lower than 50Hz in the transformer area. The conventional AC loads in the transformer area are directly powered by the 380V AC bus. Therefore, the total power of conventional AC loads in the transformer area is not considered in this embodiment and subsequent embodiments.
[0053] Step 102: Calculate the power surplus / deficit of the transformer area based on the total photovoltaic power generation and the total DC / AC load power of the transformer area. Determine the droop curve based on the first real-time voltage and the power surplus / deficit of the transformer area so that the power router can absorb power from the DC mutual support bus or transmit power to the DC mutual support bus according to the droop curve.
[0054] A schematic diagram of the control principle of the droop curve is shown below. Figure 3 As shown. See also Figure 3 The drooping curve l in the figure has the horizontal axis representing the real-time voltage V of the DC mutual support bus. dcThe vertical axis represents the transmission power P between the power router and the DC mutual support bus in the transformer area, which is the power absorbed by the power router from the DC mutual support bus or the power transmitted to the DC mutual support bus.
[0055] When the real-time voltage V of the DC mutual support bus is detected dc Not equal to the rated voltage V of the DC mutual support bus dcn At that time, the power router absorbs power from or supplies power to the DC mutual support bus according to the droop curve. Specifically, when the real-time voltage V of the DC mutual support bus... dc Less than the rated voltage V of the DC mutual support bus dcn At that time, the power router supplies power to the DC interconnection bus according to the droop curve; when the real-time voltage V of the DC interconnection bus... dc Greater than the rated voltage V of the DC mutual support bus dcn At that time, the power router absorbs power from the DC mutual support bus according to the droop curve.
[0056] For example, the formula for a sag curve can be:
[0057] P = k*(V) dcn -V dc )
[0058] In the formula, k is the droop curve coefficient.
[0059] In addition, to prevent excessive transmission power from burning out related equipment, an upper limit power P is set for the transmission power. max and lower limit power P min Correspondingly, the DC mutual support bus is equipped with a maximum voltage. With minimum voltage
[0060] In one possible implementation, see Figure 4 Step 102 may specifically include:
[0061] Step 1021: Calculate the difference between the total photovoltaic power generation in the distribution area and the total AC / DC load power in the distribution area as the power surplus or deficit of the distribution area.
[0062] Optionally, the formula for the profit and loss power of a transformer area is:
[0063] ΔP=∑P PV -∑P LD
[0064] In the formula, ΔP represents the power surplus or deficit of the transformer area, and ∑P PV It is the total photovoltaic power generation capacity of the transformer area, ∑P LD It is the total power of the AC load in the transformer area.
[0065] Step 1022: Determine the category of the transformer area based on its profit and loss power.
[0066] For example, the transformer area categories include deficit transformer areas and surplus transformer areas. If the profit and loss power of a transformer area is less than 0, the transformer area is determined to be a deficit transformer area; if the profit and loss power of a transformer area is greater than 0, the transformer area is determined to be a surplus transformer area.
[0067] In other words, if the power deficit of a distribution area is less than 0, it means that the total photovoltaic power generation of the area is less than the total DC and AC load power of the area, and the area is a deficit area. If the power deficit of a distribution area is greater than 0, it means that the total photovoltaic power generation of the area is greater than the total DC and AC load power of the area, and the area is a surplus area.
[0068] Step 1023: Determine the droop curve based on the first real-time voltage and the transformer area category, so that the power router can absorb power from or transmit power to the DC mutual support bus according to the droop curve.
[0069] The diagram illustrating the adjustment of the droop curve is shown below. Figure 5 As shown. See also Figure 5 Curve l1 represents the initial droop curve corresponding to the surplus transformer area, and curve l2 represents the initial droop curve corresponding to the deficit transformer area. It should be noted that, for ease of understanding and viewing, the surplus transformer area can be regarded as a DC power supply with adjustable output power, and the deficit transformer area can be regarded as a DC load. The slope of the droop curve l2 corresponding to the deficit transformer area is changed from negative to positive.
[0070] In one possible implementation, step 1023 may specifically include:
[0071] Step S1: If the distribution area is a subsidized distribution area, then determine the droop curve according to the first formula so that the power router can absorb power from the DC mutual assistance bus according to the droop curve.
[0072] The first formula is:
[0073] P2=k*(V dcn -V dc )-|ΔP2|
[0074] Where P2 is the power absorbed from the DC mutual support bus, V dcn The rated voltage, V dc The first real-time voltage is given, k is the droop curve coefficient, and ΔP2 is the power surplus / deficit power of the transformer area, which is the power deficit at this time.
[0075] In practical applications, when a distribution area is a subsidized area, the power router in that area determines the droop curve according to the first formula. That is, it adjusts the initial droop curve l2 according to the first formula, moves the initial droop curve up by |ΔP2| to the droop curve l′2, and starts to absorb power from the DC mutual assistance bus, which in turn causes the voltage of the DC mutual assistance bus to drop.
[0076] Step S2: If the first real-time voltage is less than the rated voltage and the transformer area is a surplus transformer area, then the droop curve is determined according to the second formula so that the power router can transmit power to the DC mutual assistance bus according to the droop curve.
[0077] The second formula is:
[0078] P1=k*(V dcn -V dc )+ΔP1
[0079] Where P1 is the power transmitted to the DC mutual support bus, V dcn The rated voltage, V dc The first real-time voltage is given, k is the droop curve coefficient, and ΔP1 is the power surplus / deficit power of the transformer area, which is the surplus power at this time.
[0080] In practical applications, if the first real-time voltage of the DC mutual support bus is less than the rated voltage of the DC mutual support bus, that is, a drop in the first real-time voltage of the DC mutual support bus is detected, it indicates that there is a power shortage in other distribution areas. In order to maintain the voltage stability of the DC mutual support bus, the power router of the surplus distribution area determines the droop curve according to the second formula, that is, adjusts the initial droop curve l1 according to the second formula, and moves the initial droop curve up by ΔP1 to the droop curve l′1, and starts to transmit power to the DC mutual support bus.
[0081] It should be noted that in practical applications, there are multiple distribution zones and corresponding power routers. When some distribution zones are underutilized and others are surplus, please refer to [the relevant documentation / reference]. Figure 5 According to the power router control method provided in the aforementioned embodiment, the power router is controlled. Specifically, the power router in the power supply area with insufficient capacity determines the droop curve according to the first formula and absorbs power from the DC mutual assistance bus according to the droop curve. The power router in the power supply area with surplus capacity determines the droop curve according to the second formula and transmits power to the DC mutual assistance bus according to the droop curve, so as to complete the power mutual assistance between multiple power supply areas and realize the local or nearby consumption of photovoltaic power.
[0082] The diagram illustrating the adjustment of the sag curve for multiple zones is shown below. Figure 6 As shown. See also Figure 6 ,|ΔP 2总 | represents the sum of the deficit power of all deficit areas, and k2 represents the sum of the droop curve coefficients of all deficit areas. ΔP 1总 Let k1 be the sum of the surplus power of all surplus transformer areas, and k1 be the sum of the droop curve coefficients of all surplus transformer areas. When the sum of the deficit power of all deficit transformer areas is |ΔP 2总 | is not equal to the sum of the surplus power of all surplus transformer areas ΔP 1总 hour( Figure 6 The sum of the deficit power of all deficit areas |ΔP 2总| Greater than the sum of the surplus power of all surplus transformer areas ΔP 1总 (In the case of) after a preset time, when each transformer area stabilizes, such as Figure 6 As shown, the operating point of multiple transformer areas has moved from point A to point B, meaning that the voltage of the DC mutual assistance bus after stabilization deviates from the rated voltage. To achieve error-free regulation of the DC mutual assistance bus, a secondary adjustment of the droop curve is required.
[0083] Step 103: After a preset time, obtain the second real-time voltage of the DC mutual assistance bus. Based on the second real-time voltage and the rated voltage of the DC mutual assistance bus, iteratively process the power surplus and deficit of the transformer area to obtain the corrected power surplus and deficit of the transformer area. Correct the droop curve according to the corrected power surplus and deficit of the transformer area so that the power router can absorb power from the DC mutual assistance bus or transmit power to the DC mutual assistance bus according to the corrected droop curve.
[0084] In one possible implementation, step 103, which iteratively processes the power deficit of the distribution area based on the second real-time voltage and the rated voltage of the DC mutual assistance bus to obtain the corrected power deficit of the distribution area, and then corrects the droop curve based on the corrected power deficit of the distribution area, may specifically include: if the second real-time voltage is less than the rated voltage and the distribution area is a deficit area, then iteratively processes the power deficit of the distribution area to obtain the corrected power deficit of the distribution area, and then corrects the droop curve based on the corrected power deficit of the distribution area.
[0085] Optionally, after each iteration of the iterative processing, the surplus or deficit power of the iterative transformer area is obtained, and the droop curve is corrected according to the surplus or deficit power of the iterative transformer area, so that the power router absorbs power from the DC mutual assistance bus according to the droop curve after iteration, and re-acquires the second real-time voltage for the next iteration, until the iteration stop condition is met.
[0086] For example, the iterative formula is:
[0087]
[0088]
[0089] Where a0 is the power surplus / deficit power of the transformer area, which is the deficit power at this time. a1 is the power surplus / deficit power of the transformer area after the first iteration. j Let V be the iterative power surplus / deficit power of the transformer area after the j-th iteration, where j≥2. dc,j-1 This is the second real-time voltage obtained during the (j-1)th iteration. The iteration stopping condition is |V dcn -V dc,j |<ε, where j≥1, and ε is the preset error.
[0090] The flowchart of the iterative processing is as follows: Figure 7As shown. When the iteration stopping condition is met, the current iteration area surplus / deficit power is output as the corrected area surplus / deficit power. The droop curve is corrected according to the corrected area surplus / deficit power so that the power router can absorb power from the DC mutual aid bus according to the corrected droop curve.
[0091] The first corrected formula is:
[0092] P′2=k*(V dcn -V′ dc )-|a J |
[0093] Where P′2 is the power absorbed from the DC mutual support bus, V dcn The rated voltage is V′. dc The second real-time voltage is given, k is the droop curve coefficient, and a J To correct for the power deficit of the transformer area, the power deficit is currently being calculated.
[0094] It should be noted that in iterative processing, if This indicates that the second real-time voltage obtained after the previous iteration is less than the rated voltage, in which case the power deficit of the iteration area needs to be reduced; if This indicates that the second real-time voltage obtained after the last iteration is greater than the rated voltage, and at this time, it is necessary to increase the surplus / deficit power of the iteration area.
[0095] It is important to note that if the iteration stopping condition is not met, before or after the first or j-th iteration, if V dcn -V dc,j If the sign of V remains unchanged, then after each station area stabilizes, i.e., after the first preset time, the next iteration will proceed; if V dcn -V dc,j If the sign changes, proceed directly to the next iteration.
[0096] In another possible implementation, step 103, which iteratively processes the power surplus / deficit of the transformer area based on the second real-time voltage and the rated voltage of the DC mutual support bus to obtain the corrected power surplus / deficit of the transformer area, and corrects the droop curve based on the corrected power surplus / deficit of the transformer area, may specifically include: if the second real-time voltage is greater than the rated voltage and the transformer area is a surplus transformer area, then iteratively processes the power surplus / deficit of the transformer area to obtain the corrected power surplus / deficit of the transformer area, and corrects the droop curve based on the corrected power surplus / deficit of the transformer area.
[0097] Optionally, after each iteration of the iterative processing, the surplus or deficit power of the iterative transformer area is obtained, and the droop curve is corrected according to the surplus or deficit power of the iterative transformer area, so that the power router can transmit power to the DC mutual assistance bus according to the droop curve after iteration, and re-acquire the second real-time voltage for the next iteration, until the iteration stop condition is met.
[0098] For example, the iterative formula is:
[0099]
[0100]
[0101] Where b0 is the power surplus / deficit power of the transformer area, which is the surplus power at this point. b1 is the power surplus / deficit power of the transformer area after the first iteration. l Let V be the iterative power surplus / deficit power of the transformer area after the l-th iteration, where l ≥ 2. dc,l-1 This is the second real-time voltage obtained during the (l-1)th iteration. The iteration stopping condition is |V dcn -V dc,l |<ε, where l≥1, and ε is the preset error.
[0102] The flowchart of the iterative processing is as follows: Figure 8 As shown. When the iteration stopping condition is met, the current iteration area surplus / deficit power is output as the corrected area surplus / deficit power. The droop curve is corrected according to the corrected area surplus / deficit power so that the power router can transmit power to the DC mutual support bus according to the corrected droop curve.
[0103] The second revised formula is:
[0104] P′1=k*(V dcn -V′ dc )-|b L |
[0105] Where P′1 is the power transmitted to the DC mutual support bus, V dcn The rated voltage is V′. dc The second real-time voltage is given, k is the droop curve coefficient, and b is the second real-time voltage. L To correct for the power deficit of the transformer area, the power at this time is the surplus power.
[0106] The specific implementation process in the iterative process can be referred to the aforementioned embodiments, and will not be repeated here.
[0107] The diagram illustrating the adjustment of the sag curve for multiple zones is shown below. Figure 9 As shown. In practical applications, there are multiple transformer substations and their corresponding power routers. See also... Figure 9 ,|ΔP 2总 | represents the sum of the deficit power of all deficit areas, and k2 represents the sum of the droop curve coefficients of all deficit areas. ΔP 1总 Let L1 be the sum of the surplus power of all surplus transformer areas, and k1 be the sum of the droop curve coefficients of all surplus transformer areas. Curve L1 is the initial droop curve corresponding to all surplus transformer areas, curve L′1 is the droop curve corresponding to all surplus transformer areas, curve L2 is the initial droop curve corresponding to all deficit transformer areas, and curve L′2 is the droop curve corresponding to all deficit transformer areas.
[0108] See Figure 9 (a) The sum of the deficit power in all deficit areas |ΔP 2总 | Greater than the sum of the surplus power of all surplus transformer areas ΔP 1总 When the second real-time voltage is lower than the rated voltage, the power router for each deficit distribution area iteratively processes the corresponding power surplus or deficit of each area, and corrects the droop curve based on the corrected power surplus or deficit. Curve L″2 represents the corrected droop curve for all deficit distribution areas. When each area stabilizes, the operating point of multiple areas moves from point B to point C, meaning that power mutual assistance between multiple areas is achieved, and error-free regulation of the DC mutual assistance bus is also realized. Optionally, at this time, part of the deficit power of the deficit distribution area is absorbed from the DC mutual assistance bus, and the other part is absorbed from the local energy storage system or AC bus.
[0109] See Figure 9 (b) The sum of the deficit power in all deficit areas |ΔP 2总 | Less than the sum of the surplus power of all surplus transformer areas ΔP 1总 When the second real-time voltage is greater than the rated voltage, the power router of each surplus transformer area iteratively processes the surplus and deficit power of each area, and corrects the droop curve according to the corrected surplus and deficit power. Curve L″1 is the corrected droop curve for all surplus transformer areas. When each area is stable, the operating point of multiple transformer areas moves from point B to point C, that is, power mutual assistance between multiple transformer areas is realized, and error-free regulation of the DC mutual assistance bus is realized at the same time. Optionally, at this time, part of the surplus power of the surplus transformer area is transmitted to the DC mutual assistance bus, and the other part is transmitted to the local energy storage system or AC bus.
[0110] In another possible implementation, if the second real-time voltage is less than the rated voltage and the distribution area is a surplus distribution area, or if the second real-time voltage is greater than the rated voltage and the distribution area is a deficit distribution area, then the surplus or deficit power of the distribution area is not iteratively processed.
[0111] It should be noted that in practical applications, there are multiple distribution zones and their corresponding routers. Some distribution zones are underutilized, while others are surplus. Let there be m underutilized distribution zones, each with a power deficit of a power unit. 10 a 20 …a m0 Then, the power surplus / deficit power of the transformer area after the first iteration can be expressed as a. 11 a 21 …a m1 ,based on It can be seen that a 11 :a 21 :…:a m1 =a 10 :a 20 :…:a m0The iterative power surplus / deficit power of the transformer area after the j-th iteration is a. 1j a 2j …a mj , any a mj It can be represented as:
[0112]
[0113] From the above equation, we can see that a 1j :a 2j :…:a mj =a 10 :a 20 :…:a m0 That is, the power absorbed by each power deficit area from the DC mutual assistance bus is allocated according to the ratio of the power surplus and deficit of each power deficit area. The power deficit area absorbs more power from the DC mutual assistance bus.
[0114] Similarly, there are n surplus transformer areas, each corresponding to a surplus or deficit power of b. 10 b 20 …b n0 Then we can get b 1l :b 2l :…:b nl =b 10 :b 20 :…:b n0 That is, the power transmitted from each surplus transformer area to the DC mutual assistance bus is allocated according to the ratio of the surplus and deficit power of each surplus transformer area. The transformer area with more power surplus also transmits more power to the DC mutual assistance bus.
[0115] In other words, the power router control method provided in this application can ensure that the transmission power is allocated according to the proportion of surplus or deficit power in each distribution area. Meanwhile, since there is no communication between the distribution areas, the connection or disconnection of one distribution area from the DC mutual support bus has no impact on the control of the power routers in other distribution areas, thus improving the scalability of the entire interconnected system composed of multiple distribution areas and corresponding power routers, and simplifying control.
[0116] This application provides a power router control method that acquires the first real-time voltage of the DC mutual support bus, the total photovoltaic power generation of the transformer area, and the total DC and AC load power of the transformer area. It calculates the transformer area's power surplus / deficit based on the total photovoltaic power generation and the total DC and AC load power, and determines a droop curve based on the first real-time voltage and the transformer area's power surplus / deficit. This allows the power router to absorb or supply power to the DC mutual support bus according to the droop curve. After a preset time, it acquires the second real-time voltage of the DC mutual support bus, and iteratively processes the transformer area's power surplus / deficit based on the second real-time voltage and the rated voltage of the DC mutual support bus to obtain a corrected power surplus / deficit and correct the droop curve. This allows the power router to absorb or supply power to the DC mutual support bus according to the corrected droop curve. This method enables power mutual support between multiple transformer areas, better local or nearby photovoltaic power consumption, and error-free regulation of the DC mutual support bus voltage.
[0117] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.
[0118] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.
Claims
1. A method of controlling an electrical energy router, characterized by, The method is applied to multiple power routers, each corresponding to a different distribution area. The method includes: The system acquires the first real-time voltage of the DC mutual support bus, the total photovoltaic power generation of the transformer area, and the total DC and AC load power of the transformer area; calculates the surplus / deficit power of the transformer area based on the total photovoltaic power generation of the transformer area and the total DC and AC load power of the transformer area; and determines the droop curve based on the first real-time voltage and the surplus / deficit power of the transformer area, so that the power router absorbs or transmits power from or to the DC mutual support bus according to the droop curve. After a preset time, the second real-time voltage of the DC mutual aid bus is obtained. If the second real-time voltage is less than the rated voltage of the DC mutual aid bus and the transformer area is a deficit area, or if the second real-time voltage is greater than the rated voltage of the DC mutual aid bus and the transformer area is a surplus area, then the surplus / deficit power of the transformer area is iteratively processed to obtain the corrected surplus / deficit power. The droop curve is corrected according to the corrected surplus / deficit power so that the power router absorbs or transmits power from or to the DC mutual aid bus according to the corrected droop curve. The iteration stops when |V dcn -V dc,j |<ε, where j≥1, ε is the preset error, V dcn The rated voltage, V dc,j This is the second real-time voltage obtained during the j-th iteration; there is no communication between the different transformer substations.
2. The electrical energy router control method of claim 1, wherein, The step of calculating the power deficit of the distribution area based on the total photovoltaic power generation and the total DC / AC load power of the distribution area, and determining the droop curve based on the first real-time voltage and the power deficit of the distribution area, includes: The difference between the total photovoltaic power generation in the transformer area and the total DC / AC load power in the transformer area is calculated as the power surplus or deficit of the transformer area. The transformer area category is determined based on the transformer area's profit and loss power, wherein the transformer area category includes deficit transformer areas and surplus transformer areas; The droop curve is determined based on the first real-time voltage and the transformer area category.
3. The electrical energy router control method of claim 2, wherein, The step of determining the transformer area category based on the transformer area's profit and loss power includes: If the profit and loss power of the transformer area is less than 0, then the transformer area is determined to be a deficit transformer area; If the power surplus of the transformer area is greater than 0, then the transformer area is determined to be a surplus transformer area.
4. The electrical energy router control method of claim 3, wherein, The step of determining the droop curve based on the first real-time voltage and the transformer area category includes: If the area is a vacant area, the droop curve is determined according to the first formula; The first formula is: If the first real-time voltage is less than the rated voltage, and the transformer area is a surplus transformer area, then the droop curve is determined according to the second formula. The second formula is: wherein, is the power delivered to or absorbed from the DC intertie bus, is the rated voltage, is the first real-time voltage, is the droop curve coefficient, is the zone balance power.
5. The electrical energy router control method of claim 1, wherein, The method further includes: After each iteration of the iterative process, the surplus or deficit power of the iterative transformer area is obtained. The droop curve is corrected according to the surplus or deficit power of the iterative transformer area, so that the power router absorbs power from or supplies power to the DC mutual assistance bus according to the droop curve after iteration, and re-acquires the second real-time voltage for the next iteration, until the iteration stop condition is met.
6. The method of claim 1 to 5, wherein, The method further includes: If the second real-time voltage is less than the rated voltage and the transformer area is a surplus transformer area, or if the second real-time voltage is greater than the rated voltage and the transformer area is a deficit transformer area, then the surplus or deficit power of the transformer area will not be iteratively processed.
7. An electrical energy router, characterized in that Used to perform the power router control method according to any one of claims 1 to 6; The power router includes: An interconnection port is used to connect to the DC mutual support bus and detect the real-time voltage of the DC mutual support bus; A photovoltaic port is used to connect distributed photovoltaic systems and detect the total photovoltaic power generation of the distributed photovoltaic system in the area. The DC load port is used to supply power to the DC loads in the transformer area and to detect the total power of the DC loads in the transformer area. The AC load port is used to supply power to the AC loads in the transformer area and to detect the total power of the AC loads in the transformer area.
8. The electrical energy router of claim 7, wherein, The power router also includes: The grid connection port is used to connect to the low-voltage side of the AC transformer on the AC busbar; Energy storage port, used to connect to the energy storage system.
9. The electrical energy router of claim 8, wherein, The interconnection port includes a converter for detecting the real-time voltage of the DC mutual support bus and for supplying power to or absorbing power from the DC mutual support bus. The converter includes a controller, which is used to calculate the power surplus / deficit of the distribution area based on the total photovoltaic power generation of the distribution area and the total DC / AC load power of the distribution area, and to determine the droop curve based on the first real-time voltage and the power surplus / deficit of the distribution area. The controller is further configured to iteratively process the power deficit of the transformer area if the second real-time voltage is less than the rated voltage of the DC mutual assistance bus and the transformer area is a deficit transformer area, or if the second real-time voltage is greater than the rated voltage of the DC mutual assistance bus and the transformer area is a surplus transformer area, to obtain a corrected power deficit of the transformer area, and to correct the droop curve according to the corrected power deficit of the transformer area.