Local area network inverter anti-countercurrent control system and control method

Abstract

The invention relates to a local area network inverter anti-countercurrent control system and method, and belongs to the field of photovoltaic technology. According to the anti-countercurrent control system and method for the local area network inverter, the router is connected with the electricity meter, the load and the micro inverters through wireless signals, the local area network is formed through configuration, and then the electricity meter controls the output power of the micro inverters according to the state of a power grid, so that countercurrent is prevented. According to the inverter anti-countercurrent control system and the control method, the local area network is used for wireless communication, the space requirement is small, a monitor does not need to be used, the equipment application and management cost is low, and the application scene range is wider.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, in particular to the field of inverter control technology, and specifically refers to a local area network inverter backflow prevention control system and control method. Background Art

[0002] Micro inverters generally refer to inverters with a power of less than or equal to 1000 watts in photovoltaic power generation systems. The full name is micro photovoltaic grid-connected inverters. Photovoltaic inverters convert the direct current generated by photovoltaic modules into alternating current for use by AC loads through inverters.

[0003] When the power generation of the photovoltaic modules in the network is large and the load demand becomes smaller, the phenomenon of reverse flow to the grid will occur. In order to protect the safety of the grid and photovoltaic modules, anti-reverse flow control is required.

[0004] In the prior art, a monitor is usually used in combination with a smart meter to achieve backflow prevention control. However, the wiring of the monitor is complex, the equipment application and management costs are high, and there are certain requirements for the environment and space. It is not suitable for application scenarios with a large load and insufficient wiring space.

[0005] Therefore, how to provide an inverter backflow prevention control system and control method with small space requirements, lower equipment application and management costs, and a wide range of application scenarios has become an urgent problem to be solved in this field. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and to provide an inverter backflow prevention control system and control method which is implemented by using local area network wireless communication, has small space requirements, low equipment application and management costs, and has a wider range of application scenarios.

[0007] In order to achieve the above-mentioned purpose, the local area network inverter backflow prevention control system of the present invention has the following structure:

[0008] At least one micro-inverter, whose input end is connected to the corresponding photovoltaic module, whose output end is connected to the load, and whose output end is also connected to the grid through an electric meter;

[0009] An electric meter connected between each of the micro-inverters and the grid, and connected to each of the micro-inverters by signals, for controlling the output power of the micro-inverters according to the grid status to prevent reverse flow;

[0010] The router is connected to the electric meter, the load and each micro inverter through wireless signals to form a local area network.

[0011] In the local area network inverter backflow prevention control system, the electric meter is used to determine whether to trigger the backflow prevention state according to the power of the power grid, and control the output power of the micro inverter according to the determination result.

[0012] In the local area network inverter backflow prevention control system, the electric meter is used to determine whether to trigger the backflow prevention state according to the power of the power grid, and control the output power of the micro inverter according to the determination result, specifically:

[0013] The electric meter detects in real time that the grid power x is in a decreasing state, and when x≥5w, the anti-backflow state is not triggered, and the electric meter controls the output power of the micro-inverter to remain unchanged; when x<5w, the anti-backflow state is triggered, and the electric meter reduces the output power until the grid power x value returns to a normal value.

[0014] In the local area network inverter backflow prevention control system, the electric meter is also used to detect the grid power x in real time. When x>100w, the electric meter controls the micro inverter to start working, controls the output power of the inverter to be y gradually increasing, and the grid power x gradually decreasing.

[0015] The present invention also provides a local area network inverter anti-backflow control method, the method comprising the following steps:

[0016] The router is connected to the electric meter, the load and at least one micro-inverter through wireless signals to form a local area network, the input end of the micro-inverter is connected to the corresponding photovoltaic module, the output end is connected to the load, and the output end is also connected to the power grid through the electric meter;

[0017] The electric meter controls the output power of the micro inverter according to the state of the power grid to prevent reverse flow.

[0018] In the local area network inverter backflow prevention control method, the electric meter controls the output power of the micro inverter according to the grid state, specifically:

[0019] The electric meter is used to determine whether to trigger the anti-backflow state according to the power of the power grid, and control the output power of the micro inverter according to the determination result.

[0020] In the local area network inverter anti-backflow control method, the electric meter is used to determine whether to trigger the anti-backflow state according to the power of the power grid, and control the output power of the micro inverter according to the determination result, specifically:

[0021] The electric meter detects in real time that the grid power x is in a decreasing state, and when x≥5w, the anti-backflow state is not triggered, and the electric meter controls the output power of the micro-inverter to remain unchanged; when x<5w, the anti-backflow state is triggered, and the electric meter reduces the output power until the grid power x value returns to a normal value.

[0022] In the local area network inverter backflow prevention control method, before the electric meter detects in real time that the power grid power x is in a decreasing state, the method further includes:

[0023] In the initial state, the micro-inverter does not work, and the electric meter detects the grid power x in real time;

[0024] When the electric meter detects that the grid power x>100w, the electric meter controls the micro inverter to start working, controls the output power of the inverter to be y gradually increasing, and the grid power x gradually decreasing.

[0025] The LAN inverter anti-backflow control system and method of the invention uses a router to connect the meter, load and each micro-inverter through wireless signals to form a local LAN, and then controls the output power of the micro-inverter according to the grid status through the meter to prevent backflow. Thus, an inverter anti-backflow control system and control method using LAN wireless communication is realized, which has small space requirements, no need to use a monitor, low equipment application and management costs, and a wider range of application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural block diagram of the local area network inverter backflow prevention control system of the present invention;

[0027] Figure 2 The figure is a flow chart of the anti-backflow control method of the local area network inverter of the present invention. DETAILED DESCRIPTION

[0028] In order to more clearly understand the technical content of the present invention, the following embodiments are given in detail.

[0029] See also Figure 1 As shown, it is a structural block diagram of the local area network inverter backflow prevention control system of the present invention.

[0030] In one embodiment, the local area network inverter backflow prevention control system includes:

[0031] Multiple micro-inverters (3 shown in the figure), whose input ends are connected to corresponding PV panels, whose output ends are connected to loads, and whose output ends are also connected to the grid through an electric meter;

[0032] An electric meter connected between each of the micro-inverters and the grid, and connected to each of the micro-inverters by signals, for controlling the output power of the micro-inverters according to the grid status to prevent reverse flow;

[0033] The router is connected to the electric meter, the load and each micro inverter through wireless signals to form a local area network.

[0034] In a more preferred embodiment, the electric meter is used to determine whether to trigger the anti-backflow state according to the power of the power grid, and control the output power of the micro inverter according to the determination result.

[0035] In a further preferred embodiment, the electric meter is used to determine whether to trigger the anti-backflow state according to the power of the power grid, and control the output power of the micro inverter according to the determination result, specifically:

[0036] The electric meter detects in real time that the grid power x is in a decreasing state, and when x≥5w (this value can be set according to the actual application scenario), the anti-backflow state is not triggered, and the electric meter controls the output power of the micro-inverter to remain unchanged; when x<5w, the anti-backflow state is triggered, and the electric meter reduces the output power until the grid power x value returns to a normal value.

[0037] In a more preferred embodiment, the electric meter is also used to detect the grid power x in real time. When x>100w (this value can be set according to the actual application scenario), the electric meter controls the micro-inverter to start working, controls the output power of the inverter to gradually increase to y, and the grid power x gradually decreases.

[0038] The present invention also provides a local area network inverter anti-backflow control method, the method is as follows Figure 2 As shown, the following steps are included:

[0039] The router is connected to the electric meter, the load and at least one micro-inverter through wireless signals to form a local area network, the input end of the micro-inverter is connected to the corresponding photovoltaic module, the output end is connected to the load, and the output end is also connected to the power grid through the electric meter;

[0040] The electric meter controls the output power of the micro inverter according to the state of the power grid to prevent reverse flow.

[0041] In a more preferred embodiment, the electric meter controls the output power of the micro inverter according to the grid status, specifically:

[0042] The electric meter is used to determine whether to trigger the anti-backflow state according to the power of the power grid, and control the output power of the micro inverter according to the determination result.

[0043] In a further preferred embodiment, the electric meter is used to determine whether to trigger the anti-backflow state according to the power of the power grid, and control the output power of the micro inverter according to the determination result, specifically:

[0044] The electric meter detects in real time that the grid power x is in a decreasing state, and when x≥5w (this value can be set according to the actual application scenario), the anti-backflow state is not triggered, and the electric meter controls the output power of the micro-inverter to remain unchanged; when x<5w, the anti-backflow state is triggered, and the electric meter reduces the output power until the grid power x value returns to a normal value.

[0045] In a more preferred embodiment, before the electric meter detects in real time that the power grid power x is in a decreasing state, the method further includes:

[0046] In the initial state, the micro-inverter does not work, and the electric meter detects the grid power x in real time;

[0047] When the electric meter detects that the grid power x>100w (this value can be set according to the actual application scenario), the electric meter controls the micro inverter to start working, controls the output power of the inverter to gradually increase to y, and the grid power x gradually decreases.

[0048] In practical applications, the LAN inverter anti-backflow control system and method of the present invention first configures the wireless meter and the micro-inverter in the same network, and different devices are networked through UDP, so that the devices can communicate with each other; the wireless meter is used to detect the power of the power grid in real time on the power grid side. When the meter detects that the power of the power grid is very small or triggers the backflow to the Internet, the relevant instructions are sent in the local area network to control the output of the micro-inverter. When the micro-inverter receives the relevant instructions, it starts to control the output power to increase the power detected on the power grid side, thereby achieving a relatively safe anti-backflow state. The specific control method may include the following steps:

[0049] 1. In the initial state, the micro inverter does not work, and the power consumption detected by the electric meter is x;

[0050] 2. When the grid power x>100w is detected, the meter will send a control command to control the micro inverter to start working, and the output power of the inverter is y. At this time, y gradually increases, and x also gradually decreases;

[0051] 3. When the grid power x is less than 100w, the meter sends a command to control the micro inverter to keep the current output power unchanged, which is close to the control effect of 0 output;

[0052] 4. When the household load decreases, the grid power will jump. When x < 5w, the anti-reverse flow control is turned on. At this time, the meter sends a stop output command to control the micro inverter to stop output and wait for the x power value to return to normal.

[0053] 5. When the x value returns to normal, follow the above steps again to control.

[0054] The advantages of the LAN inverter backflow prevention control system and method of the present invention are: no need for a monitor, easy application, ability to achieve backflow prevention function, and multiple micro inverters in the same LAN can be controlled simultaneously without mutual influence.

[0055] The LAN inverter anti-backflow control system and method of the invention uses a router to connect the meter, load and each micro-inverter through wireless signals to form a local LAN, and then controls the output power of the micro-inverter according to the grid status through the meter to prevent backflow. Thus, an inverter anti-backflow control system and control method using LAN wireless communication is realized, which has small space requirements, no need to use a monitor, low equipment application and management costs, and a wider range of application scenarios.

[0056] In this specification, the present invention has been described with reference to specific embodiments thereof. However, it is apparent that various modifications and variations may be made without departing from the spirit and scope of the present invention. Therefore, the specification and drawings should be regarded as illustrative rather than restrictive.

Claims

1. A local area network inverter backflow prevention control system, characterized in that: include: At least one micro-inverter, whose input end is connected to the corresponding photovoltaic module, whose output end is connected to the load, and whose output end is also connected to the grid through an electric meter; An electric meter connected between each of the micro-inverters and the grid, and connected to each of the micro-inverters by signals, for controlling the output power of the micro-inverters according to the grid status to prevent reverse flow; The router is connected to the electric meter, the load and each micro inverter through wireless signals to form a local area network.

2. The local area network inverter backflow prevention control system according to claim 1, characterized in that: The electric meter is used to determine whether to trigger the anti-backflow state according to the power of the power grid, and control the output power of the micro inverter according to the determination result.

3. The local area network inverter backflow prevention control system according to claim 2, characterized in that: The electric meter is used to determine whether to trigger the anti-backflow state according to the power of the power grid, and control the output power of the micro inverter according to the determination result, specifically: The electric meter detects in real time that the grid power x is in a decreasing state, and when x≥5w, the anti-backflow state is not triggered, and the electric meter controls the output power of the micro-inverter to remain unchanged; when x<5w, the anti-backflow state is triggered, and the micro-inverter reduces the output power until the grid x value returns to a normal value.

4. The local area network inverter backflow prevention control system according to claim 3, characterized in that: The electric meter is also used to detect the power x of the power grid in real time. When x>100w, the electric meter controls the micro inverter to start working, controls the output power of the inverter to increase gradually to y, and the power x of the power grid decreases gradually.

5. A method for preventing backflow in a local area network inverter, characterized in that: The method comprises the following steps: The router is connected to the electric meter, the load and at least one micro-inverter through wireless signals to form a local area network, the input end of the micro-inverter is connected to the corresponding photovoltaic module, the output end is connected to the load, and the output end is also connected to the power grid through the electric meter; The electric meter controls the output power of the micro inverter according to the state of the power grid to prevent reverse flow.

6. The method for preventing backflow in a local area network inverter according to claim 5, characterized in that: The electric meter controls the output power of the micro inverter according to the grid status, specifically: The electric meter is used to determine whether to trigger the anti-backflow state according to the power of the power grid, and control the output power of the micro inverter according to the determination result.

7. The method for preventing reverse flow of a local area network inverter according to claim 6, characterized in that: The electric meter is used to determine whether to trigger the anti-backflow state according to the power of the power grid, and control the output power of the micro inverter according to the determination result, specifically: The electric meter detects in real time that the grid power x is in a decreasing state, and when x≥5w, the anti-backflow state is not triggered, and the electric meter controls the output power of the micro-inverter to remain unchanged; when x<5w, the anti-backflow state is triggered, and the electric meter reduces the output power until the grid power x value returns to a normal value.

8. The method for preventing backflow in a local area network inverter according to claim 7, characterized in that: Before the electric meter detects in real time that the power grid power x is in a decreasing state, the method further includes: In the initial state, the micro-inverter does not work, and the electric meter detects the grid power x in real time; When the electric meter detects that the grid power x>100w, the electric meter controls the micro inverter to start working, controls the output power of the inverter to be y gradually increasing, and the grid power x gradually decreasing.

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