A distributed energy system and control method

Abstract

The application discloses a kind of distributed energy systems and control method, system includes: converter and controller;The input end of converter is used to connect renewable energy, renewable energy is photovoltaic component and / or fan;Converter has droop characteristic or virtual synchronous machine characteristic;Controller is used to detect the electrical parameter of converter, electrical parameter includes voltage, power or frequency;According to the comparison result of electrical parameter and preset value and load priority, the switching of load is controlled.For better match the relationship between load and power supply, without the active feedback of the state of load, the application detects the electrical parameter of converter, controller compares the electrical parameter of converter with preset value, according to the comparison result and load priority, to automatically control the switching of load in distributed energy system.Balance the relationship between power supply and load, so that power reaches balance, and can guarantee that priority high load is powered on priority, guarantee priority high load normal operation.

Description

Technical Field

[0001] This application relates to the field of new energy power generation technology, specifically to a distributed energy system and control method. Background Technology

[0002] Currently, the power output of photovoltaic modules is increasing, and small wind turbines are also gradually being used. With the continuous improvement of photovoltaic module power and the decrease in cost, balcony photovoltaic applications are gradually being promoted and applied.

[0003] In distributed energy systems, such as photovoltaic modules and small wind turbines, renewable energy sources are located close to the power load, which can reduce transmission and distribution losses.

[0004] The electricity generated by the photovoltaic modules on the balcony can be directly fed into the room to power loads such as home appliances and electronic products. However, renewable energy, loads, and the power grid form a complex distributed system. Due to the volatility of renewable energy, how to effectively manage the relationship between power generation and consumption and ensure the reliable and stable operation of the distributed energy system is a current concern.

[0005] Currently, distributed energy systems all require load feedback status signals for closed-loop control. However, in scenarios with a large number of loads, the sheer number of feedback signals leads to complex control; furthermore, the methods described above are not suitable for distributed energy systems with loads that lack feedback signals. Summary of the Invention

[0006] In view of this, this application provides a distributed energy system and control method that can balance the relationship between energy and load even when the load is not in a feedback state.

[0007] This application provides a distributed energy system, including: a converter and a controller;

[0008] The input of the converter is used to connect to renewable energy sources, such as photovoltaic modules and / or wind turbines;

[0009] The converter has droop characteristics or virtual synchronous machine characteristics;

[0010] The controller is used to detect the electrical parameters of the converter, including voltage, power, or frequency; and to control the switching of loads based on the comparison results of the electrical parameters with preset values ​​and load priority.

[0011] Preferably, the controller is specifically used to send a load input instruction to the load control device according to the load priority when the electrical parameters are greater than the corresponding preset value; and to cut off the load according to the load priority when the electrical parameters are less than the corresponding preset value.

[0012] Preferably, the controller is specifically used to determine the required increase in power based on the electrical parameters when the electrical parameters are greater than the corresponding preset value, and to control the load input based on the required increase in power and load priority.

[0013] The controller is specifically used to determine the required power reduction based on the electrical parameters when they are less than the corresponding preset values, and to control the load to be cut off based on the required power reduction and load priority.

[0014] Preferably, the controller is specifically configured to, when the electrical parameter is greater than the corresponding preset value, obtain the power that needs to be increased based on the difference between the electrical parameter and the corresponding preset value, and control the load to be put into operation based on the power that needs to be increased and the load priority; when the electrical parameter is less than the corresponding preset value, obtain the power that needs to be reduced based on the difference between the electrical parameter and the corresponding preset value, and control the load to be cut off based on the power that needs to be reduced and the load priority.

[0015] Preferably, the preset value includes at least two of the following: a first preset value and a second preset value; the first preset value is greater than the second preset value;

[0016] The controller is specifically used to determine the required increase in power based on the difference between the electrical parameters and the first preset value when the electrical parameters are greater than the first preset value, and to control the load input based on the required increase in power and load priority when the electrical parameters are greater than the second preset value and less than the first preset value, and to control the load input based on the required increase in power and load priority when the electrical parameters are greater than the second preset value and less than the first preset value.

[0017] Preferably, the preset value further includes at least two of the following: a third preset value and a fourth preset value; the third preset value is less than the fourth preset value;

[0018] When the electrical parameter is less than the third preset value, the power to be reduced is obtained based on the difference between the electrical parameter and the third preset value, and the load is cut off according to the power to be reduced and the load priority. When the electrical parameter is less than the fourth preset value but greater than the third preset value, the power to be reduced is obtained based on the difference between the electrical parameter and the fourth preset value, and the load is cut off according to the power to be reduced and the load priority. The third preset value and the fourth preset value are both less than the first preset value and the second preset value.

[0019] Preferably, it further includes: a load control device;

[0020] The load control device includes a switching switch and a control circuit;

[0021] The control circuit receives instructions from the controller and controls the switching switch to operate according to the instructions. The switching switch is used to connect the load.

[0022] Preferably, the renewable energy source is a photovoltaic module, the load is a household device, and the load priority is ranked according to the importance of the household device, or the load priority is a preset priority.

[0023] This application provides a control method for a distributed energy system, the distributed energy system including: a converter; the input terminal of the converter is used to connect to renewable energy, the renewable energy being photovoltaic modules and / or wind turbines; the converter has droop characteristics or virtual synchronous machine characteristics;

[0024] The method includes:

[0025] Detect the electrical parameters of the converter, including voltage, power, or frequency;

[0026] Based on the comparison results between electrical parameters and preset values, the switching of loads is controlled according to load priority.

[0027] Preferably, based on the comparison results of electrical parameters with preset values, the switching of loads is controlled according to load priority, specifically including:

[0028] When the electrical parameters are greater than the corresponding preset values, the load is controlled to be put on according to the load priority; when the electrical parameters are less than the corresponding preset values, the load is controlled to be cut off according to the load priority.

[0029] Preferably, when the electrical parameters are greater than the corresponding preset values, the load is controlled according to the load priority, specifically including:

[0030] When the electrical parameters are greater than the corresponding preset values, the required power is obtained based on the electrical parameters, and the load is controlled based on the required power and load priority.

[0031] When electrical parameters are lower than the corresponding preset value, the load is cut off according to load priority, specifically including:

[0032] When the electrical parameters are less than the corresponding preset values, the power that needs to be reduced is obtained based on the electrical parameters, and the load is cut off according to the power that needs to be reduced and the load priority.

[0033] Preferably, based on the comparison results of electrical parameters with preset values, the switching of loads is controlled according to load priority, specifically including:

[0034] When the electrical parameters are greater than the corresponding preset values, the required increase in power is obtained based on the difference between the electrical parameters and the corresponding preset values, and the load input is controlled according to the required increase in power and load priority.

[0035] When the electrical parameters are less than the corresponding preset values, the power that needs to be reduced is obtained based on the difference between the electrical parameters and the corresponding preset values, and the load is cut off according to the power that needs to be reduced and the load priority.

[0036] Preferably, the preset values ​​include at least two of the following: a first preset value and a second preset value; the first preset value is greater than the second preset value; when the electrical parameter is greater than the corresponding preset value, the required increase in power is obtained based on the difference between the electrical parameter and the corresponding preset value, and the load input is controlled according to the required increase in power and load priority, specifically including:

[0037] When the electrical parameter is greater than the first preset value, the required increase in power is obtained based on the difference between the electrical parameter and the first preset value, and the load is controlled based on the required increase in power and load priority; when the electrical parameter is greater than the second preset value but less than the first preset value, the required increase in power is obtained based on the difference between the electrical parameter and the second preset value, and the load is controlled based on the required increase in power and load priority; the first preset value is not equal to the second preset value.

[0038] Preferably, the preset value further includes at least two of the following: a third preset value and a fourth preset value; the third preset value is less than the fourth preset value; when the electrical parameter is less than the corresponding preset value, the power to be reduced is obtained based on the difference between the electrical parameter and the corresponding preset value, and the load is cut off according to the power to be reduced and the load priority, specifically including:

[0039] When the electrical parameter is less than the third preset value, the power to be reduced is obtained based on the difference between the electrical parameter and the third preset value, and the load is cut off according to the power to be reduced and the load priority; when the electrical parameter is less than the fourth preset value but greater than the third preset value, the power to be reduced is obtained based on the difference between the electrical parameter and the fourth preset value, and the load is cut off according to the power to be reduced and the load priority; both the third preset value and the fourth preset value are less than the first preset value and the second preset value.

[0040] Therefore, this application has the following beneficial effects:

[0041] The distributed energy system provided in this application can include renewable energy sources such as photovoltaic modules or wind turbines. Since the power generation of photovoltaic modules or wind turbines is limited by natural conditions, it will fluctuate. Therefore, in order to better match the relationship between load and power supply, and without requiring active feedback from the load, this application detects the electrical parameters of the converter, including voltage, power, or frequency. The converter is configured with droop characteristics or virtual synchronous machine characteristics. For example, the converter can be an inverter. The controller compares the converter's electrical parameters with preset values ​​and automatically controls the switching of loads in the distributed energy system based on the comparison results and load priorities. This balances the relationship between power supply and load, achieving power equilibrium, and ensuring that high-priority loads are supplied first, guaranteeing their normal operation. Attached Figure Description

[0042] Figure 1 A schematic diagram of a distributed energy system provided in an embodiment of this application;

[0043] Figure 2 A diagram illustrating the relationship between power and frequency in droop control provided in this application embodiment;

[0044] Figure 3 A diagram illustrating the relationship between power and frequency in droop control provided in this application embodiment;

[0045] Figure 4 A diagram showing the relationship between active power and voltage in droop control is provided in an embodiment of this application.

[0046] Figure 5 A diagram illustrating the relationship between reactive power and voltage in droop control, provided in an embodiment of this application;

[0047] Figure 6 A schematic diagram of another distributed energy system provided in the embodiments of this application;

[0048] Figure 7 A flowchart illustrating a control method for a distributed energy system provided in an embodiment of this application. Detailed Implementation

[0049] To enable those skilled in the art to better understand the technical solutions provided in the embodiments of this application, the application scenarios of this application will be introduced below.

[0050] The distributed energy system provided in this application may include photovoltaic modules or wind turbines, such as the increasingly widely used balcony photovoltaic power generation. Photovoltaic modules are installed between floors, and the electrical energy output from these modules can power indoor appliances such as lights, refrigerators, or air conditioners. Since photovoltaic modules or wind turbines are subject to fluctuations due to natural conditions, the switching of loads in the distributed energy system can be automatically controlled to better match the relationship between load and power generation, without requiring active feedback from the load.

[0051] For example, a photovoltaic module has a power of about 500W, which means that 1-2 modules can be installed on a typical balcony, with a total power of 1kW. With the advancement of photovoltaic module technology, the total power of photovoltaic modules that can be installed on a balcony can be further increased.

[0052] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the embodiments of this application will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0053] See Figure 1 The figure is a schematic diagram of a distributed energy system provided in an embodiment of this application.

[0054] The distributed energy system provided in this application includes: a converter 100, a load control device 200, and a controller 300. In this embodiment, the system includes a load control device 200 as an example. In addition, the load control device 200 can be integrated with the load. This application does not specifically limit the specific form of the product.

[0055] The input terminal of converter 100 is used to connect to renewable energy 400, which is a photovoltaic module or a wind turbine; the output terminal of converter 100 is connected to load control device 200.

[0056] Converter 100 has droop characteristics or virtual synchronous machine characteristics; the output voltage and power of a converter with droop characteristics or virtual synchronous machine characteristics are inversely proportional, and the frequency is also inversely proportional to the power.

[0057] This application does not specifically limit the type of renewable energy source 400, but may include at least one of photovoltaic modules and wind turbines. The converter 100 corresponding to the photovoltaic module includes an inverter, or includes an inverter and a DC-DC converter.

[0058] The load control device 200 is used to receive instructions from the controller 300 to switch loads; this distributed energy system can connect multiple loads. Figure 1 Taking n loads as an example, where n is an integer greater than or equal to 2, the n loads can be prioritized to provide power to the loads more efficiently. For example, in a scenario with balcony solar power generation, the refrigerator has a higher priority than the washing machine. When electricity is limited, power should be supplied to the refrigerator in a limited way, while lower-priority loads such as the washing machine should be switched off first.

[0059] The load control device 200 includes a load switching switch and a control circuit, namely, a circuit that drives the load switching switch to operate. Each load can be connected to the distributed energy system through a load switching switch.

[0060] The controller 300 is used to detect the electrical parameters of the converter, including voltage, power or frequency; and to send load switching instructions to the load control device 200 based on the comparison results of the electrical parameters with preset values ​​and according to the load priority.

[0061] This application does not specifically limit the method of setting load priorities. For example, priorities can be set according to the importance of the loads or pre-selected priorities. The importance of the loads can also be dynamically adjusted over time. For example, if the renewable energy source is a photovoltaic module and the load is a household device, such as a home appliance, the load priority can be sorted according to the importance of the household device, or the load priority can be a preset priority.

[0062] Figure 1The diagram only briefly illustrates controller 300. It should be understood that controller 300 represents a control device, including the main circuit and the controller. The main circuit is responsible for collecting energy from various energy sources and connecting it to the load control device 200.

[0063] Because the output voltage and power of a converter with droop characteristics are inversely proportional, and the frequency is also inversely proportional to the power, the voltage or frequency can be adjusted by controlling power changes. Power changes can be achieved by switching loads on and off the distributed energy system. For example, when the frequency of the distributed energy system is too high, it is necessary to increase the power and thus lower the frequency, which can be achieved by adding loads to the distributed energy system.

[0064] The embodiments of this application do not specifically limit the specific location of electrical parameter detection. For example, the output voltage or frequency of the converter 100 can be detected, or the voltage and frequency at other locations in the distributed energy system can be detected, such as the input voltage or frequency of the load.

[0065] Furthermore, the distributed energy system provided in this application embodiment may also include a converter 500 and an energy storage medium 600, such as an energy storage battery. The converter 500 is also controlled by the controller 300, and the converter 500 can be a bidirectional AC-DC converter, which can realize the charging and discharging control of the energy storage medium 600. The combination of the converter 500 and the energy storage medium 600 can serve as a load of the distributed energy system or as an input power source of the distributed energy system.

[0066] The distributed energy system provided in this application can include renewable energy sources such as photovoltaic modules or wind turbines. Since the power generation of photovoltaic modules or wind turbines is limited by natural conditions, it will fluctuate. Therefore, in order to better match the relationship between load and power source, and without requiring active feedback from the load, this application detects the electrical parameters of the converter, compares these parameters with preset values, and automatically controls the switching of loads in the distributed energy system based on the comparison results and load priorities. This balances the relationship between power source and load, achieving power equilibrium, and ensures that high-priority loads are supplied first, guaranteeing their normal operation.

[0067] This application does not specifically limit the droop relationship between frequency and power, nor does it specifically limit the droop relationship between voltage and power. For example, regarding the relationship between frequency and power, the controller can directly obtain the corresponding power based on the frequency of the distributed energy system, or it can obtain the corresponding power based on the difference between the frequency of the distributed energy system and a preset value. These two scenarios will be described below.

[0068] See Figure 2 The figure shows the relationship between power and frequency in a droop control according to an embodiment of this application.

[0069] Figure 2 The horizontal axis represents power, and the vertical axis represents frequency. The maximum power is Pmax, and the minimum power is Pin. For example, if the rated frequency is 50Hz, the power corresponding to the rated frequency is Pset.

[0070] It should be understood that when the electrical parameter is frequency, the frequency of the distributed power system can be detected, and the detected frequency can be compared with a preset value. Specifically, the controller is used to send a load-adding command to the load control device according to load priority when the electrical parameter is greater than the corresponding preset value; and to send a load-cutting command to the load control device according to load priority when the electrical parameter is less than the corresponding preset value.

[0071] This application does not specifically limit the preset value for the corresponding frequency; the specific value can be selected based on the actual application scenario. For example, when the detected frequency is greater than the preset value, it is necessary to lower the frequency. In this case, the frequency can be lowered by increasing the power. Increasing the power requires adding a load, i.e., increasing the load. Specifically, high-priority loads can be connected to the distributed energy system.

[0072] The controller is specifically used to determine the required increase in power based on the electrical parameters when the electrical parameters exceed the corresponding preset values, and to send a command to the load control device to put the load into operation based on the required increase in power and load priority.

[0073] For example, the required power increase can be proportional to the current detection frequency, such as a linear ratio, allowing the power increase to be obtained directly from the detection frequency. Alternatively, the relationship between frequency and power can be pre-created in a table, allowing the required power increase to be obtained directly from the table.

[0074] The controller is specifically used to determine the required power reduction based on the electrical parameters when they are less than the corresponding preset values, and to send a load cut-off command to the load control device based on the required power reduction and load priority.

[0075] For example, the power increase needed can be proportional to the current detection frequency, such as a linear ratio, allowing the required power reduction to be obtained directly from the detection frequency. Alternatively, the relationship between frequency and power can be pre-created in a table, allowing the required power reduction to be obtained directly from the table.

[0076] See Figure 3 The figure shows the relationship between power and frequency in a droop control according to an embodiment of this application.

[0077] contrast Figure 2 and Figure 3 It can be seen that, Figure 3 The frequency corresponding to the power Pset in the data has a plateau. Figure 2 and Figure 3These are two different drooping characteristics.

[0078] In addition to utilizing the droop characteristic between frequency and power, the droop characteristic between voltage and power can also be utilized. The relationship between voltage and active power, and between voltage and reactive power, is illustrated below with reference to the attached diagram.

[0079] See Figure 4 The figure shows the relationship between active power and voltage in a droop control according to an embodiment of this application.

[0080] Figure 4 The horizontal axis represents active power, with the active power range being [Pmin, Pmax]. The vertical axis represents DC voltage Vdc_out, and the voltage corresponding to the rated operating point is Vdc_set.

[0081] See Figure 5 The figure shows the relationship between reactive power and voltage in a droop control according to an embodiment of this application.

[0082] Figure 5 The horizontal axis represents reactive power, with the reactive power range being [Qinductive, Qcapacitive]. The vertical axis represents the voltage Vout of the distributed power system, and the voltage corresponding to the rated operating point is Vset.

[0083] For ease of understanding, the embodiments of this application use the relationship between frequency and power to introduce the load switching control in a distributed energy system.

[0084] The above describes obtaining the power to be changed directly based on the detection frequency. The following describes obtaining the power to be changed based on the difference between the detection frequency and the preset value.

[0085] The controller, specifically, is used to determine the required increase in power based on the difference between the electrical parameters and the corresponding preset values ​​when electrical parameters exceed a preset value. It then sends a load-input command to the load control device based on the required increase in power and load priority. For example, the larger the absolute value of the difference between the electrical parameters and the corresponding preset value, the greater the required increase in power. This application does not specifically limit whether the difference is positive or negative; when the electrical parameters are subtracted from the preset value, the difference is positive.

[0086] The controller, specifically, is used to determine the required power reduction based on the difference between the electrical parameters and the corresponding preset values ​​when electrical parameters are less than the preset values. It then sends a load-cutting command to the load control device based on the required power reduction and load priority. For example, the larger the absolute value of the difference between the electrical parameters and the corresponding preset values, the greater the power reduction required. This application does not specifically limit whether the difference is positive or negative; when the preset value is subtracted from the electrical parameters, the difference is positive.

[0087] The above introduction uses a preset value as one level. It should be understood that multiple preset values ​​can be set, comparing the electrical parameters with different preset values ​​to correspond to different load switching gradients. A detailed explanation follows. For ease of understanding and description, the explanation will focus on two preset values ​​of different magnitudes when the electrical parameters are greater than the preset value, and also on two preset values ​​of different magnitudes when the electrical parameters are less than the preset value. It should be understood that preset values ​​can include more levels of values.

[0088] One possible implementation is that the preset value includes at least two of the following: a first preset value and a second preset value; the first preset value is greater than the second preset value.

[0089] The controller is specifically used to determine the required increase in power based on the difference between the electrical parameters and the first preset value when the electrical parameters are greater than the first preset value, and to send a first activation command to the load control device based on the required increase in power and load priority; when the electrical parameters are greater than the second preset value and less than the first preset value, it determines the required increase in power based on the difference between the electrical parameters and the second preset value, and to send a second activation command to the load control device based on the required increase in power and load priority.

[0090] For example, if the power of the load corresponding to the first input instruction is greater than the power of the load corresponding to the second input instruction, multiple loads can be input if one load does not meet the required increase in power.

[0091] The preset values ​​also include at least two of the following: a third preset value and a fourth preset value; the third preset value is less than the fourth preset value;

[0092] When the electrical parameter is less than the third preset value, the power to be reduced is obtained based on the difference between the electrical parameter and the third preset value, and a first cut-off command is sent to the load control device based on the power to be reduced and the load priority; when the electrical parameter is less than the fourth preset value but greater than the third preset value, the power to be reduced is obtained based on the difference between the electrical parameter and the fourth preset value, and a second cut-off command is sent to the load control device based on the power to be reduced and the load priority; both the third preset value and the fourth preset value are less than the first preset value and the second preset value.

[0093] The first load cut-off command cuts off a load with a power greater than the second load cut-off command cuts off a load with a power greater than the second load cut-off command. Additionally, if the power of a single load is insufficient to meet the required power reduction, multiple loads can be cut off.

[0094] The distributed energy system provided in this application uses multiple preset values ​​to more finely manage load switching. Combined with load priorities, it ensures that higher-priority loads are powered first. If multiple loads with the same priority are being switched, power matching is considered, prioritizing the switching of loads whose power matches the power required for the power change.

[0095] Specifically, the load control device includes a switching switch and a control circuit;

[0096] The control circuit receives instructions from the controller and controls the switching switch to operate according to the instructions. The switching switch is used to connect the load.

[0097] The distributed energy system provided in this application embodiment allows for load switching without feedback signals. When a load without feedback signals is switched on, it causes changes in electrical parameters such as system frequency and / or converter frequency. The controller determines whether the switching is successful and the magnitude of the power change by detecting these changes in electrical parameters. When the controller issues a load switching command but does not detect a reverse change in electrical parameters such as frequency and / or voltage, it can be determined that there is a fault in the load's control circuit or the load itself. When the frequency or voltage cannot be reversed by switching or controlling the load continuously, the controller can quickly and orderly shut down the converter on the input side through communication to prevent more serious faults.

[0098] See Figure 6 This figure is a schematic diagram of another distributed energy system provided in an embodiment of this application.

[0099] One possible implementation is that renewable energy could include both photovoltaic modules and wind turbines. Figure 6 In this paper, we will take a distributed energy system, which includes multiple photovoltaic modules and a wind turbine, as an example. It should be understood that the number of photovoltaic modules and wind turbines can be arbitrarily combined, or it can include only one type of renewable energy.

[0100] Photovoltaic module 401 supplies power to the load through converter 101, photovoltaic module 402 supplies power to the load through converter 102, and wind turbine 403 supplies power to the load through converter 103.

[0101] Figure 6 The diagram only shows that the controller 300 controls other devices, but the power supply path between the converter and the load is not fully illustrated.

[0102] This application does not specifically limit the type of load switching switch in the load control device 200.

[0103] Based on the distributed energy system provided in the above embodiments, this application also provides a control method for the distributed energy system, which will be described in detail below.

[0104] See Figure 7 The figure is a flowchart of a control method for a distributed energy system provided in an embodiment of this application.

[0105] This embodiment provides a control method for a distributed energy system, which includes: a converter; the input terminal of the converter is used to connect to renewable energy sources, such as photovoltaic modules and / or wind turbines; the converter has droop characteristics or virtual synchronous machine characteristics.

[0106] The method includes:

[0107] S701: Detects the electrical parameters of the converter, including voltage, power, or frequency;

[0108] S702: Controls load switching based on the comparison results of electrical parameters with preset values ​​and load priority.

[0109] The control method for a distributed energy system provided in this application can include renewable energy sources such as photovoltaic modules or wind turbines. Since the power generation of photovoltaic modules or wind turbines is limited by natural conditions, it will fluctuate. Therefore, in order to better match the relationship between load and power source, and without requiring active feedback from the load, this application detects the electrical parameters of the converter, compares these parameters with preset values, and automatically controls the switching of loads in the distributed energy system based on the comparison results and load priorities. This balances the relationship between power source and load, achieving power equilibrium, and ensures that high-priority loads are supplied first, guaranteeing their normal operation.

[0110] The following describes the case of load switching directly based on electrical parameters.

[0111] Based on the comparison between electrical parameters and preset values, a load switching command is sent to the load control device, specifically including:

[0112] When the electrical parameters are greater than the corresponding preset value, a command to put the load on is sent to the load control device according to the load priority; when the electrical parameters are less than the corresponding preset value, a command to cut off the load is sent to the load control device according to the load priority.

[0113] Specifically, when the electrical parameters exceed the corresponding preset values, a load activation command is sent to the load control device according to the load priority, including:

[0114] When the electrical parameters exceed the corresponding preset values, the required power is obtained based on the electrical parameters, and a command to put the load into operation is sent to the load control device based on the required power and load priority.

[0115] When the electrical parameters are less than the corresponding preset value, a load cut-off command is sent to the load control device according to the load priority, specifically including:

[0116] When the electrical parameters are less than the corresponding preset values, the power that needs to be reduced is obtained based on the electrical parameters, and a command to cut off the load is sent to the load control device according to the power to be reduced and the load priority.

[0117] The following describes the situation where load switching is performed based on the deviation between electrical parameters and preset values.

[0118] Specifically, based on the comparison results between electrical parameters and preset values, a load switching command is sent to the load control device, including:

[0119] When the electrical parameters are greater than the corresponding preset values, the power that needs to be increased is obtained based on the difference between the electrical parameters and the corresponding preset values, and an instruction to put the load into operation is sent to the load control device based on the power that needs to be increased and the load priority.

[0120] When the electrical parameters are less than the corresponding preset values, the power that needs to be reduced is obtained based on the difference between the electrical parameters and the corresponding preset values. Then, a command to cut off the load is sent to the load control device based on the power to be reduced and the load priority.

[0121] The following describes the implementation method of multiple preset values ​​and load switching at different levels. This application does not specifically limit the number of preset values ​​or the specific load switching levels; they can be set and selected according to actual conditions. For ease of description and understanding, two preset values ​​are used as examples below.

[0122] Specifically, the preset values ​​include at least two of the following: a first preset value and a second preset value; the first preset value is greater than the second preset value; when the electrical parameter is greater than the corresponding preset value, the required increase in power is obtained based on the difference between the electrical parameter and the corresponding preset value, and a command to put the load into operation is sent to the load control device according to the required increase in power and load priority, specifically including:

[0123] When the electrical parameter is greater than the first preset value, the required increase in power is obtained based on the difference between the electrical parameter and the first preset value, and a first activation command is sent to the load control device based on the required increase in power and load priority; when the electrical parameter is greater than the second preset value but less than the first preset value, the required increase in power is obtained based on the difference between the electrical parameter and the second preset value, and a second activation command is sent to the load control device based on the required increase in power and load priority; the first preset value is not equal to the second preset value.

[0124] Specifically, the preset values ​​also include at least two of the following: a third preset value and a fourth preset value; the third preset value is less than the fourth preset value; when the electrical parameter is less than the corresponding preset value, the power to be reduced is obtained based on the difference between the electrical parameter and the corresponding preset value, and a load cut-off command is sent to the load control device according to the power to be reduced and the load priority, specifically including:

[0125] When the electrical parameter is less than the third preset value, the power to be reduced is obtained based on the difference between the electrical parameter and the third preset value, and a first cut-off command is sent to the load control device based on the power to be reduced and the load priority; when the electrical parameter is less than the fourth preset value but greater than the third preset value, the power to be reduced is obtained based on the difference between the electrical parameter and the fourth preset value, and a second cut-off command is sent to the load control device based on the power to be reduced and the load priority; both the third preset value and the fourth preset value are less than the first preset value and the second preset value.

[0126] The distributed energy system provided in this application uses multiple preset values ​​to more finely manage load switching. Combined with load priorities, it ensures that higher-priority loads are powered first. If multiple loads with the same priority are being switched, power matching is considered, prioritizing the switching of loads whose power matches the power required for the power change.

[0127] The control method provided in this application allows for load switching without feedback signals. When a load without feedback signals is switched on, it causes changes in electrical parameters such as system frequency and / or converter frequency. The controller determines whether the switching is successful and the magnitude of the power change by detecting these changes in electrical parameters. When the controller issues a load switching command but does not detect a reverse change in electrical parameters such as frequency and / or voltage, it can be determined that there is a fault in the load's control circuit or the load itself. When the frequency or voltage cannot be reversed by switching or controlling the load continuously, the controller can quickly and orderly shut down the converter on the input side through communication to prevent more serious faults.

[0128] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A distributed energy system, characterized in that, include: Converters and controllers; The input terminal of the converter is used to connect to renewable energy sources, namely photovoltaic modules and / or wind turbines; The converter has droop characteristics or virtual synchronous machine characteristics. The output voltage and power of the converter with droop characteristics or virtual synchronous machine characteristics are inversely proportional, and the frequency is inversely proportional to the power. The controller is used to detect the electrical parameters of the converter, including voltage, power, or frequency; and to control the switching of loads based on the comparison results of the electrical parameters with preset values ​​and load priority.

2. The system according to claim 1, characterized in that, The controller is specifically used to send a load input instruction to the load control device according to the load priority when the electrical parameter is greater than the corresponding preset value; and to cut off the load according to the load priority when the electrical parameter is less than the corresponding preset value.

3. The system according to claim 2, characterized in that, The controller is specifically used to determine the required power increase based on the electrical parameters when the electrical parameters are greater than the corresponding preset value, and to control the load input based on the required power increase and the load priority. The controller is specifically used to obtain the power that needs to be reduced based on the electrical parameters when the electrical parameters are less than the corresponding preset value, and to control the load to be cut off based on the power that needs to be reduced and the load priority.

4. The system according to claim 1, characterized in that, The controller is specifically configured to, when the electrical parameter is greater than the corresponding preset value, obtain the power that needs to be increased based on the difference between the electrical parameter and the corresponding preset value, and control the load to be put into operation based on the power that needs to be increased and the load priority; when the electrical parameter is less than the corresponding preset value, obtain the power that needs to be reduced based on the difference between the electrical parameter and the corresponding preset value, and control the load to be cut off based on the power that needs to be reduced and the load priority.

5. The system according to claim 4, characterized in that, The preset value includes at least two of the following: a first preset value and a second preset value; the first preset value is greater than the second preset value; The controller is specifically configured to, when the electrical parameter is greater than the first preset value, obtain the required increase in power based on the difference between the electrical parameter and the first preset value, and control the load input based on the required increase in power and load priority; when the electrical parameter is greater than the second preset value and less than the first preset value, obtain the required increase in power based on the difference between the electrical parameter and the second preset value, and control the load input based on the required increase in power and load priority.

6. The system according to claim 5, characterized in that, The preset value also includes at least two of the following: a third preset value and a fourth preset value; the third preset value is less than the fourth preset value; When the electrical parameter is less than the third preset value, the power to be reduced is obtained based on the difference between the electrical parameter and the third preset value, and the load is controlled to be cut off based on the power to be reduced and the load priority; when the electrical parameter is less than the fourth preset value and greater than the third preset value, the power to be reduced is obtained based on the difference between the electrical parameter and the fourth preset value, and the load is controlled to be cut off based on the power to be reduced and the load priority; the third preset value and the fourth preset value are both less than the first preset value and the second preset value.

7. The system according to any one of claims 1-6, characterized in that, Also includes: Load control device; The load control device includes a switching switch and a control circuit; The control circuit is used to receive instructions from the controller and control the switching switch to operate according to the instructions. The switching switch is used to connect the load.

8. The system according to any one of claims 1-6, characterized in that, The renewable energy source is a photovoltaic module, the load is a household device, and the load priority is ranked according to the importance of the household device, or the load priority is a preset priority.

9. A control method for a distributed energy system, characterized in that, The distributed energy system includes: a converter; the input terminal of the converter is used to connect to renewable energy, which is a photovoltaic module and / or a wind turbine; the converter has droop characteristics or virtual synchronous machine characteristics, and the output voltage and power of the converter with droop characteristics or virtual synchronous machine characteristics are inversely proportional, and the frequency is inversely proportional to the power; The method includes: Detect the electrical parameters of the converter, including voltage, power, or frequency; Based on the comparison results between the electrical parameters and preset values, the switching of loads is controlled according to load priority.

10. The control method according to claim 9, characterized in that, The step of controlling load switching based on load priority according to the comparison result of the electrical parameters and preset values ​​specifically includes: When the electrical parameter is greater than the corresponding preset value, the load is controlled to be put into operation according to the load priority; when the electrical parameter is less than the corresponding preset value, the load is controlled to be cut off according to the load priority.

11. The control method according to claim 10, characterized in that, When the electrical parameter is greater than a corresponding preset value, the load is controlled according to the load priority, specifically including: When the electrical parameter is greater than the corresponding preset value, the power that needs to be increased is obtained based on the electrical parameter, and the load is controlled based on the power that needs to be increased and the load priority. When the electrical parameter is less than a corresponding preset value, the load is cut off according to the load priority, specifically including: When the electrical parameters are less than the corresponding preset values, the power that needs to be reduced is obtained based on the electrical parameters, and the load is cut off based on the power that needs to be reduced and the load priority.

12. The control method according to claim 9, characterized in that, The step of controlling load switching based on load priority according to the comparison result of the electrical parameters and preset values ​​specifically includes: When the electrical parameter is greater than the corresponding preset value, the power that needs to be increased is obtained based on the difference between the electrical parameter and the corresponding preset value, and the load input is controlled based on the power that needs to be increased and the load priority. When the electrical parameter is less than the corresponding preset value, the power that needs to be reduced is obtained based on the difference between the electrical parameter and the corresponding preset value, and the load is cut off based on the power that needs to be reduced and the load priority.

13. The control method according to claim 12, characterized in that, The preset values ​​include at least two of the following: a first preset value and a second preset value; the first preset value is greater than the second preset value; when the electrical parameter is greater than the corresponding preset value, the required increase in power is obtained based on the difference between the electrical parameter and the corresponding preset value, and the load is controlled based on the required increase in power and load priority, specifically including: When the electrical parameter is greater than the first preset value, the required increase in power is obtained based on the difference between the electrical parameter and the first preset value, and the load is controlled based on the required increase in power and load priority; when the electrical parameter is greater than the second preset value and less than the first preset value, the required increase in power is obtained based on the difference between the electrical parameter and the second preset value, and the load is controlled based on the required increase in power and load priority; the first preset value is not equal to the second preset value.

14. The control method according to claim 13, characterized in that, The preset value also includes at least two of the following: a third preset value and a fourth preset value; the third preset value is less than the fourth preset value; when the electrical parameter is less than the corresponding preset value, the power to be reduced is obtained based on the difference between the electrical parameter and the corresponding preset value, and the load is controlled to be cut off based on the power to be reduced and the load priority, specifically including: When the electrical parameter is less than the third preset value, the power to be reduced is obtained based on the difference between the electrical parameter and the third preset value, and the load is controlled to be cut off based on the power to be reduced and the load priority; when the electrical parameter is less than the fourth preset value and greater than the third preset value, the power to be reduced is obtained based on the difference between the electrical parameter and the fourth preset value, and the load is controlled to be cut off based on the power to be reduced and the load priority; both the third preset value and the fourth preset value are less than the first preset value and the second preset value.

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