Distributed photovoltaic power generation power grid-connected system and method

Abstract

The invention discloses a distributed photovoltaic power generation power grid-connected system and method, and relates to the technical field of photovoltaic power generation grid connection, and the system comprises the following parts: a photovoltaic power generation module, a control module, an inversion module, a metering module, an energy storage module, a grid-connected module, and an intelligent control module. The photovoltaic power generation modules are formed by connecting a plurality of photovoltaic cell panel arrays in series through cables, signals are transmitted to the intelligent control module for calculation after numerical value collection, the photovoltaic power generation modules are converged and then led to the inversion module, the inversion module is processed and then led to the metering module, and the metering module is connected with the intelligent control module. The metering module is respectively communicated with the storage module and the grid-connected module; the potential of solar energy is fully excavated through the intelligent control module, the energy utilization efficiency is greatly improved, energy waste is avoided, the electric energy quality problem caused by power fluctuation is reduced, and more stable and reliable electric power supply is provided for residents and a power grid.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power generation grid connection, and in particular to a distributed photovoltaic power generation grid connection system and method. Background Art

[0002] Against the backdrop of the world's growing urgent demand for clean energy, distributed photovoltaic power generation systems have gradually become popular and widely used in various fields.

[0003] However, the existing distributed photovoltaic power generation grid-connected system still has shortcomings that cannot be ignored in many aspects. There are bottlenecks in improving power generation efficiency, the stability of system operation needs to be strengthened, and the level of intelligent management is still insufficient. For example, the output power of photovoltaic cells will change with changes in factors such as light intensity, temperature and load. It is difficult for the system to always work at the maximum power point of photovoltaic cells, resulting in the inability to fully utilize solar energy resources and greatly reducing power generation efficiency. At the same time, there is a lack of equipment to accumulate detailed system operation data, which is not conducive to the evaluation and improvement of system performance, nor is it conducive to the optimization and upgrade of subsequent systems and the design reference of new systems.

[0004] These limitations have severely restricted the further development and widespread application of distributed photovoltaic power generation systems. New technical solutions are urgently needed to break through the difficulties and achieve a qualitative leap. Summary of the invention

[0005] The purpose of the present invention is to provide a distributed photovoltaic power generation grid-connected system and method, which uses an intelligent control module to control the MPPT controller to change the output power of the photovoltaic cell so that it always works at the maximum power point of the photovoltaic cell, thereby making full use of solar energy resources.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A distributed photovoltaic power generation grid-connected system includes the following components: a photovoltaic power generation module, a control module, an inverter module, a metering module, an energy storage module, a grid-connected module, and an intelligent control module;

[0008] The photovoltaic power generation module uses several photovoltaic battery panel arrays connected in series through cables to form a group of photovoltaic power generation modules. The group of photovoltaic power generation modules are respectively connected to control modules. After collecting numerical values, the control module transmits the signal to the intelligent control module for calculation. After obtaining reliable data, the reverse signal manipulation control module regulates the photovoltaic power generation module. The photovoltaic power generation modules are collected and then lead to the inverter module. The inverter module is led to the metering module after processing. After the metering module processes the numerical values, the signal is transmitted to the intelligent control module. The intelligent control module reversely regulates the distribution of electric energy through the obtained data. The metering module is respectively led to the storage module and the grid-connected module. The electric energy passing through the storage module is used for daily electricity consumption of residents. After passing through the grid-connected module and the transformer module, it is connected to the power grid.

[0009] The control module is equipped with a sensing module, which can sense and record the electric energy I and voltage U of the photovoltaic power generation module, and transmit the signals to the intelligent control module.

[0010] The control module has an MPPT control module built in, and controls the photovoltaic power generation module by performing signal control through the intelligent control module.

[0011] The inverter adopts a high-frequency isolated inverter topology, converts the AC output into high-voltage DC through a rectifier bridge, and then outputs the AC signal through a full-bridge inverter. The rectification on the source side of the transformer and the inverter on the secondary side are adjusted separately through decoupling; the DC signal is converted into a positive half-cycle sine wave through an interleaved flyback structure, and then adjusted into a full-cycle sine wave through a thyristor.

[0012] The photovoltaic panels used in the photovoltaic power generation module are installed with a tracking bracket to ensure maximum sunlight reception. The surface of the photovoltaic panels is covered with an anti-reflective coating and is equipped with a solid frame and protective glass.

[0013] A distributed photovoltaic power generation grid-connected method comprises the following steps:

[0014] S1 Data perception and collection: The built-in sensing module of the control module senses and records the power I and voltage V of the photovoltaic power generation module; data is collected every 3 seconds and transmitted to the intelligent control module for recording and calculation;

[0015] S2 Power calculation preparation: The intelligent control module calculates the received electric energy I and voltage V data to obtain the power P:

[0016] P=I×V

[0017] S3 Power analysis and comparison: Calculate the corresponding power P, and use the obtained power P signal for the next step of calculation. By taking the derivative of the voltage V, we get:

[0018]

[0019] By analyzing the P-V curve of the array, the obtained value is compared with 0;

[0020] S4 Power Tracking and Regulation Decision: When , with the help of the MPPT control module built in the signal control unit, increase the working power of the photovoltaic power generation module to achieve maximum power tracking;

[0021] When , reduce the working power of the photovoltaic power generation module through the MPPT control module built in the signal control unit to achieve maximum power tracking;

[0022] S5 Electric Energy Conversion and Transmission: The electric energy generated by the photovoltaic power generation module is collected and then transmitted to the inverter module. The inverter module functions to convert the direct current generated by the photovoltaic power generation into alternating current. After this processing step, the electric energy leads to the metering module;

[0023] S6 Electric Energy Distribution and Grid Connection: After the metering module completes the metering value, it transmits the value to the intelligent control module for calculation. Through control, the electric energy is preferentially transmitted to the energy storage module for residential electricity use. When the residential electricity consumption is met, the remaining electric energy is transmitted to the voltage transformation module and then并入 the grid to charge fees.

[0024] The described intelligent control module preferentially transmits the electric energy to the energy storage module for residential electricity use. Its strategy is to store the energy storage module to 80% first, and then the electric energy is并入 the grid. When the electric energy in the energy storage module is lower than 30%, continue to store the electric energy into the energy storage module.

[0025] The described metering module will record the power value once every 3 seconds and continuously collect the values of the most recent 6 hours. The data collected is transmitted to the intelligent control module for calculating its S value:

[0026]

[0027] Where: N is the total number of the most recent 6-hour numerical data; X i is the i-th recorded value; u is the overall mean; generally, it is considered that X < U - 3S, or X > U + 3S is regarded as an outlier; when the values continuously detected by the intelligent control module satisfy the above outlier conditions three times in a row, the circuit is disconnected.

[0028] In the step of electric energy distribution and grid connection, the intelligent control module accesses the real-time electricity price information, thereby dynamically adjusting the timing of the electric energy并入 the grid according to the electricity price to achieve the maximization of economic benefits.

[0029] The intelligent control module is equipped with a database to classify and store all data to ensure the security, integrity and traceability of the data.

[0030] First, a distributed photovoltaic power generation grid-connected system is built. Several photovoltaic panel arrays are connected in series through cables to form photovoltaic power generation modules, and each photovoltaic power generation module is connected to a corresponding control module.

[0031] In actual operation, the built-in sensing module of the control module senses and records the power I and voltage V of the photovoltaic power generation module every 3 seconds, and transmits the data to the intelligent control module. After receiving the power and voltage data, the intelligent control module calculates the power P.

[0032] The corresponding result is obtained by taking the derivative of the voltage V, and then the P-V curve of the array is analyzed and compared with 0. When the result is greater than 0, the intelligent control module sends a signal to control the MPPT control module built into the control unit to increase the working power of the photovoltaic power generation module; when the result is less than 0, its working power is reduced to achieve maximum power tracking.

[0033] The electricity generated by the photovoltaic power generation module is collected and transmitted to the inverter module, where the DC power is converted into AC power and then passed to the metering module. The metering module records the power value every 3 seconds, continuously collects the values ​​for the last 6 hours, and transmits these data to the intelligent control module. The intelligent control module calculates the S value according to a specific formula to determine whether there is an abnormal value. If an abnormal value is detected three times in a row, the circuit is disconnected.

[0034] The intelligent control module operates according to the strategy of giving priority to transmitting electric energy to the energy storage module for residents' electricity use. After the electric energy storage in the energy storage module reaches 80%, the remaining electric energy is connected to the grid; when the electric energy in the energy storage module is less than 30%, the electric energy continues to be stored in the energy storage module. The electric energy passing through the storage module is used for residents' daily electricity use, and the electric energy passing through the grid-connected module is connected to the grid after passing through the transformer module.

[0035] During sunny days, photovoltaic power generation is high, and the intelligent control module quickly adjusts the power to make the system work at the maximum power point, and stores most of the power in the energy storage module first to meet the residents' nighttime power needs. On rainy days or when the light is weak, the intelligent control module flexibly distributes power according to the real-time power and the power of the energy storage module to ensure that residents' power consumption is not affected, and can directly or directly take power from the power grid.

[0036] During the operation of the system, each module is regularly inspected and maintained to ensure stable performance and accurate data. In particular, the photovoltaic panels are cleaned and inspected to ensure power generation efficiency; the control module, inverter module and metering module are functionally tested and calibrated to ensure normal operation and precise control of the system.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] Energy utilization efficiency is significantly improved: The MPPT controller is precisely regulated by the intelligent control module, so that the photovoltaic cells always work at the maximum power point, fully tapping the potential of solar energy, greatly improving energy utilization efficiency and avoiding energy waste.

[0039] Power output is more stable and reliable: Accurate power tracking and control reduces power quality issues caused by power fluctuations, providing residents and power grids with a more stable and reliable power supply.

[0040] Enhanced electricity security for residents: Electricity is preferentially transmitted to the energy storage module for residents to use, and a reasonable energy storage strategy is set to ensure that residents can get stable power support under different electricity usage conditions, thereby improving the security of residents' electricity use.

[0041] Improved system safety: Through the continuous monitoring of power values ​​and abnormal value judgment by the metering module, potential circuit faults can be discovered and handled in a timely manner, effectively reducing system operation risks and improving overall safety.

[0042] Cost-effectiveness optimization: More efficient energy utilization and stable power output reduce equipment loss and maintenance costs, while improving the economic benefits of the system.

[0043] Stronger adaptability: It can adapt to different lighting conditions and load changes, flexibly adjust the working state of photovoltaic cells, and maintain good operating performance in various environments.

[0044] Outstanding contribution to environmental protection: more effective use of solar energy reduces dependence on traditional energy, reduces carbon emissions, and has positive significance for environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A distributed photovoltaic power generation grid-connected system diagram of the present invention;

[0046] Figure 2 This is a step diagram of a distributed photovoltaic power generation grid-connected method according to the present invention. Specific implementation methods

[0047] The technical solutions in the embodiments of the present invention will be fully described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0048] As shown in the figure, a distributed photovoltaic power generation grid-connected system includes the following components: photovoltaic power generation module, control module, inverter module, metering module, energy storage module, grid-connected module, and intelligent control module;

[0049] The photovoltaic power generation module uses several photovoltaic battery panel arrays connected in series through cables to form a group of photovoltaic power generation modules. The group of photovoltaic power generation modules are respectively connected to control modules. After collecting numerical values, the control module transmits the signal to the intelligent control module for calculation. After obtaining reliable data, the reverse signal manipulation control module regulates the photovoltaic power generation module. The photovoltaic power generation modules are collected and then lead to the inverter module. The inverter module is led to the metering module after processing. After the metering module processes the numerical values, the signal is transmitted to the intelligent control module. The intelligent control module reversely regulates the distribution of electric energy through the obtained data. The metering module is respectively led to the storage module and the grid-connected module. The electric energy passing through the storage module is used for daily electricity consumption of residents. After passing through the grid-connected module and the transformer module, it is connected to the power grid.

[0050] The control module is equipped with a sensing module, which can sense and record the electric energy I and voltage U of the photovoltaic power generation module, and transmit the signals to the intelligent control module.

[0051] The control module has an MPPT control module built in, and controls the photovoltaic power generation module by performing signal control through the intelligent control module.

[0052] The inverter adopts a high-frequency isolated inverter topology, converts the AC output into high-voltage DC through a rectifier bridge, and then outputs the AC signal through a full-bridge inverter. The rectification on the source side of the transformer and the inverter on the secondary side are adjusted separately through decoupling; the DC signal is converted into a positive half-cycle sine wave through an interleaved flyback structure, and then adjusted into a full-cycle sine wave through a thyristor.

[0053] The photovoltaic panels used in the photovoltaic power generation module are installed with a tracking bracket to ensure maximum sunlight reception. The surface of the photovoltaic panels is covered with an anti-reflective coating and is equipped with a solid frame and protective glass.

[0054] A distributed photovoltaic power generation grid-connected method comprises the following steps:

[0055] S1 Data perception and collection: The built-in sensing module of the control module senses and records the power I and voltage V of the photovoltaic power generation module; data is collected every 3 seconds and transmitted to the intelligent control module for recording and calculation;

[0056] S2 Power calculation preparation: The intelligent control module calculates the received electric energy I and voltage V data to obtain the power P:

[0057] P=I×V

[0058] S3 Power analysis and comparison: Calculate the corresponding power P, and use the obtained power P signal for the next step of calculation. By taking the derivative of the voltage V, we get:

[0059]

[0060] By analyzing the P-V curve of the array, the obtained value is compared with 0;

[0061] S4 Power Tracking and Regulation Decision: When this is the case, the MPPT control module built into the signal control unit is used to increase the working power of the photovoltaic power generation module to achieve maximum power tracking;

[0062] When this is the case, the MPPT control module built into the signal control unit is used to reduce the working power of the photovoltaic power generation module to achieve maximum power tracking;

[0063] S5 Electric Energy Conversion and Transmission: The electric energy generated by the photovoltaic power generation module is collected and then transmitted to the inverter module. The inverter module functions to convert the direct current generated by the photovoltaic power generation into alternating current. After this processing step, the electric energy is sent to the metering module;

[0064] S6 Electric Energy Distribution and Grid Connection: After the metering module completes the metering value, the value is transmitted to the intelligent control module for calculation. Through control, the electric energy is preferentially transmitted to the energy storage module for residential electricity use. When the residential electricity consumption is met, the remaining electric energy is transmitted to the voltage transformation module and then并入 the grid to charge fees.

[0065] The intelligent control module preferentially transmits the electric energy to the energy storage module for residential electricity use. Its strategy is to store the energy storage module to 80% first, and then the electric energy is并入 the grid. When the electric energy in the energy storage module is lower than 30%, the electric energy is continuously stored in the energy storage module.

[0066] The metering module will record the power value once every 3 seconds and continuously collect the values for the most recent 6 hours. The data collected is transmitted to the intelligent control module for calculating its S value:

[0067]

[0068] where: N is the total number of the most recent 6-hour numerical data; X i is the i-th recorded value; u is the overall mean; generally, it is considered that X < U - 3S, or X > U + 3S is regarded as an outlier; when the values continuously detected by the intelligent control module satisfy the above outlier conditions three times in a row, the circuit is disconnected.

[0069] In the step of electric energy distribution and grid connection, the intelligent control module accesses the real-time electricity price information, thereby dynamically adjusting the timing of the electric energy并入 the grid according to the electricity price to achieve the maximization of economic benefits.

[0070] The intelligent control module is equipped with a database to classify and store all data to ensure the security, integrity and traceability of the data.

[0071] First, a distributed photovoltaic power generation grid-connected system is built. Several photovoltaic panel arrays are connected in series through cables to form photovoltaic power generation modules, and each photovoltaic power generation module is connected to a corresponding control module.

[0072] In actual operation, the built-in sensing module of the control module senses and records the power I and voltage V of the photovoltaic power generation module every 3 seconds, and transmits the data to the intelligent control module. After receiving the power and voltage data, the intelligent control module calculates the power P.

[0073] The corresponding result is obtained by taking the derivative of the voltage V, and then the P-V curve of the array is analyzed and compared with 0. When the result is greater than 0, the intelligent control module sends a signal to control the MPPT control module built into the control unit to increase the working power of the photovoltaic power generation module; when the result is less than 0, its working power is reduced to achieve maximum power tracking.

[0074] The electricity generated by the photovoltaic power generation module is collected and transmitted to the inverter module, where the DC power is converted into AC power and then passed to the metering module. The metering module records the power value every 3 seconds, continuously collects the values ​​for the last 6 hours, and transmits these data to the intelligent control module. The intelligent control module calculates the S value according to a specific formula to determine whether there is an abnormal value. If an abnormal value is detected three times in a row, the circuit is disconnected.

[0075] The intelligent control module operates according to the strategy of giving priority to transmitting electric energy to the energy storage module for residents' electricity use. After the electric energy storage in the energy storage module reaches 80%, the remaining electric energy is connected to the grid; when the electric energy in the energy storage module is less than 30%, the electric energy continues to be stored in the energy storage module. The electric energy passing through the storage module is used for residents' daily electricity use, and the electric energy passing through the grid-connected module is connected to the grid after passing through the transformer module.

[0076] During sunny days, photovoltaic power generation is high, and the intelligent control module quickly adjusts the power to make the system work at the maximum power point, and stores most of the power in the energy storage module first to meet the residents' nighttime power needs. On rainy days or when the light is weak, the intelligent control module flexibly distributes power according to the real-time power and the power of the energy storage module to ensure that residents' power consumption is not affected, and can directly or directly take power from the power grid.

[0077] During the operation of the system, each module is regularly inspected and maintained to ensure stable performance and accurate data. In particular, the photovoltaic panels are cleaned and inspected to ensure power generation efficiency; the control module, inverter module and metering module are functionally tested and calibrated to ensure normal operation and precise control of the system.

Claims

1. A distributed photovoltaic power generation grid-connected system, comprising the following components: photovoltaic power generation module, control module, inverter module, metering module, energy storage module, grid-connected module, intelligent control module; The photovoltaic power generation module uses several photovoltaic battery panel arrays connected in series through cables to form a group of photovoltaic power generation modules. The group of photovoltaic power generation modules are respectively connected to control modules. After collecting numerical values, the control module transmits the signal to the intelligent control module for calculation. After obtaining reliable data, the reverse signal manipulation control module regulates the photovoltaic power generation module. The photovoltaic power generation modules are collected and then lead to the inverter module. The inverter module is led to the metering module after processing. After the metering module processes the numerical values, the signal is transmitted to the intelligent control module. The intelligent control module reversely regulates the distribution of electric energy through the obtained data. The metering module is respectively led to the storage module and the grid-connected module. The electric energy passing through the storage module is used for daily electricity consumption of residents. After passing through the grid-connected module and the transformer module, it is connected to the power grid.

2. A distributed photovoltaic power generation grid-connected system according to claim 1, characterized in that: The control module is equipped with a sensing module, which can sense and record the electric energy I and voltage U of the photovoltaic power generation module, and transmit the signals to the intelligent control module.

3. A distributed photovoltaic power generation grid-connected system according to claim 1, characterized in that: The control module has an MPPT control module built in, and controls the photovoltaic power generation module by performing signal control through the intelligent control module.

4. A distributed photovoltaic power generation grid-connected system according to claim 1, characterized in that: The inverter adopts a high-frequency isolated inverter topology, converts the AC output into high-voltage DC through a rectifier bridge, and then outputs the AC signal through a full-bridge inverter. The rectification on the source side of the transformer and the inverter on the secondary side are adjusted separately through decoupling; the DC signal is converted into a positive half-cycle sine wave through an interleaved flyback structure, and then adjusted into a full-cycle sine wave through a thyristor.

5. A distributed photovoltaic power generation grid-connected system according to claim 1, characterized in that: The photovoltaic panels used in the photovoltaic power generation module are installed with a tracking bracket to ensure maximum sunlight reception. The surface of the photovoltaic panels is covered with an anti-reflective coating and is equipped with a solid frame and protective glass.

6. A distributed photovoltaic power generation grid-connected method, comprising the following steps: S1 Data perception and collection: The built-in sensing module of the control module senses and records the power I and voltage V of the photovoltaic power generation module; data is collected every 3 seconds and transmitted to the intelligent control module for recording and calculation; S2 Power calculation preparation: The intelligent control module calculates the received electric energy I and voltage V data to obtain the power P: P=I×V, S3 Power analysis and comparison: Calculate the corresponding power P, and use the obtained power P signal for the next step of calculation. By taking the derivative of the voltage V, we get: By analyzing the P-V curve of the array, the obtained The value is compared with 0; S4 power tracking adjustment decision: When the signal is used to control the MPPT control module built into the control unit, the working power of the photovoltaic power generation module is increased to achieve maximum power tracking; when When the signal is turned on, the MPPT control module built into the signal control unit reduces the working power of the photovoltaic power generation module to achieve maximum power tracking; S5 Power conversion and transmission: The power generated by the photovoltaic power generation module is collected and transmitted to the inverter module. The inverter module converts the direct current generated by the photovoltaic power generation into alternating current. The power after this processing step is passed to the metering module; S6 Power distribution and grid connection: After the metering module completes the metering value, it transmits the value to the intelligent control module for calculation. Through control, the power is preferentially transmitted to the energy storage module for residential electricity use. When the residents' electricity consumption is met, the remaining power is transmitted to the transformation module and then connected to the grid to charge fees.

7. A distributed photovoltaic power generation grid-connected method according to claim 6, characterized in that: The intelligent control module preferentially transmits electric energy to the energy storage module for residential use. Its strategy is to preferentially store the energy storage module to 80%, and then integrate the electric energy into the power grid. When the electric energy of the energy storage module is lower than 30%, the electric energy continues to be stored in the energy storage module.

8. A distributed photovoltaic power generation grid-connected method according to claim 6, characterized in that: The metering module will record the power value every 3 seconds and continuously collect the values ​​for the last 6 hours, and transmit the collected data to the intelligent control module to calculate its S value: Where: N is the total number of the most recent 6-hour numerical data; X i is the i-th recorded value; u is the overall mean; generally, it is considered that X < U - 3S, or X > U + 3S is regarded as an outlier; when the values continuously detected by the intelligent control module three times all meet the above outlier conditions, the circuit is disconnected.

9. A distributed photovoltaic power generation grid-connected method according to claim 6, characterized in that: In the steps of power distribution and grid connection, the intelligent control module accesses real-time electricity price information, thereby dynamically adjusting the timing of power connection to the grid according to the electricity price to maximize economic benefits.

10. A distributed photovoltaic power generation grid-connected method according to claim 6, characterized in that: The intelligent control module is equipped with a database to classify and store all data to ensure the security, integrity and traceability of the data.

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