Photovoltaic array data acquisition device

Abstract

The invention relates to the technical field of photovoltaic equipment, in particular to a photovoltaic array data acquisition device which comprises a photovoltaic array composed of a plurality of photovoltaic modules, an environment signal acquisition module, a voltage and current acquisition and isolation module, an upper computer module and a variable resistance module, and the positive electrode and the negative electrode of the photovoltaic array are connected with the positive electrode and the negative electrode of the variable resistance module respectively. The voltage and current acquisition and isolation module is connected in parallel with the photovoltaic array; the output end of the environment signal acquisition module is connected with the upper computer module, and the output end of the voltage and current acquisition isolation module is connected with the upper computer module. According to the device, photovoltaic array environment signals and electrical signals can be collected in real time, and the sampling frequency and the resolution ratio can be flexibly adjusted; the system has a good data acquisition effect, the acquisition process is rapid and safe, the operation and maintenance cost of the photovoltaic array is reduced, and the operation and maintenance efficiency is improved.

Description

Technical Field

[0001] The present application relates to the technical field of photovoltaic equipment, and in particular, to a photovoltaic array data acquisition device. Background Art

[0002] With the continuous growth of global energy demand and the increasing attention to environmental protection, solar photovoltaic power generation, as a clean and renewable energy source, has been rapidly developed and widely used in my country. As the core part of the photovoltaic power generation system, the performance of the photovoltaic array directly affects the power generation efficiency of the entire system. In order to improve the operating stability and power generation efficiency of the photovoltaic power generation system, it is particularly important to collect the data generated by the photovoltaic array in real time and accurately. Among them, the IV characteristics (current-voltage characteristics) of the photovoltaic array are the key parameters for evaluating its performance and efficiency. IV data detection mainly involves measuring the current and voltage of the photovoltaic array under different irradiance and temperature conditions to obtain important parameters such as its maximum power point, fill factor, short-circuit current and open-circuit voltage.

[0003] The traditional IV curve scanning method takes a long time to complete a complete test, which is not suitable for rapid diagnosis and monitoring of large-scale photovoltaic arrays. In the case of large environmental changes, the accuracy of existing detection equipment may be affected, resulting in inaccurate data, and there is a certain degree of isolation between environmental signal acquisition and voltage and current acquisition, which is not conducive to unified data processing and analysis. In addition. High-end IV test equipment is expensive, which increases the operation and maintenance cost of photovoltaic power generation systems. Some detection equipment is bulky and is not convenient for on-site testing in outdoor photovoltaic power stations. Summary of the invention

[0004] In order to solve the above problems, the present application provides a photovoltaic array data acquisition device.

[0005] To achieve the above objectives, this application adopts the following technical solutions:

[0006] A photovoltaic array data acquisition device includes a photovoltaic array 1 composed of a plurality of photovoltaic components, an environmental signal acquisition module 2, a voltage and current acquisition isolation module 3, a host computer module 4 and a variable resistance module 5;

[0007] The environmental signal acquisition module 2 is used to collect real-time data of irradiance and temperature of the photovoltaic power station, convert the analog quantity into 4-20mA and connect it to the data acquisition card;

[0008] The voltage and current acquisition isolation module 3 is used for real-time output voltage and current acquisition of the photovoltaic array, and converts the output voltage and current analog quantity into 4-20mA and connects it to the data acquisition card;

[0009] The host computer module 4 is used to collect each analog signal and upload it to the PC for analysis;

[0010] The variable resistor module 5 is used to change the resistance value connected to the two sides of the photovoltaic array, so as to obtain the output voltage and current of the photovoltaic array under different resistance values;

[0011] The positive and negative electrodes of the photovoltaic array 1 are respectively connected to the positive and negative electrodes of the variable resistor module 5, and the voltage and current acquisition isolation module 3 is connected in parallel with the photovoltaic array 1;

[0012] The output end of the environmental signal acquisition module 2 is connected to the host computer module 4 , and the output end of the voltage and current acquisition isolation module 3 is connected to the host computer module 4 .

[0013] Furthermore, the environmental signal acquisition module 2 includes a solar radiation sensor and an adhesive thermal resistor patch temperature probe. Preferably, the solar radiation sensor has a range of 0-2000 W / m 2 , resolution 1W / m 2 The temperature measurement range of the adhesive thermal resistor is -50℃-150℃.

[0014] The range of the solar radiation sensor of the environmental signal acquisition module is 0-2000W / m 2 , meeting the requirements of daily irradiance collection in most areas; the resolution is 1W / m 2 , meeting the accuracy requirements of environmental signal acquisition; the temperature measurement range of the adhesive thermal resistor is -50℃-150℃, which meets the test requirements of the photovoltaic power generation system under normal circumstances.

[0015] Furthermore, the voltage and current acquisition isolation module 3 adopts a voltage and current transmitter with a rated voltage of DC0-1000V, a rated current of DC0-100A, a rated output of DC4-20mA, a response time of less than 200ms, and an accuracy of 0.2%.

[0016] Since the voltage and current output by the photovoltaic array are not only determined by environmental factors, but also related to the size of the load connected to the photovoltaic system, in order to isolate the photovoltaic array from data acquisition systems such as microcontrollers and prevent excessive voltage and current from damaging weak electrical components, a voltage and current acquisition transmitter with isolation function is used as an electrical data acquisition element. The isolation module uses ASIC professional integrated circuits, which greatly reduces the number of components, improves circuit reliability and long-term stability, and has a response time of less than 200ms, realizing real-time current monitoring and conversion.

[0017] Furthermore, the host computer module 4 adopts an 8-channel standard analog input acquisition module, an input range of 4-20mA, an AD sampling rate of 1MHz, a Modbus communication update speed of 10Hz, and a data acquisition card with a communication interface RS485.

[0018] Furthermore, the variable resistor module 5 adopts an electronic load tester with a continuous scanning test function.

[0019] In order to obtain the IV data of the photovoltaic array, the variable resistor module uses an electronic load tester. The electronic load tester provides a scanning test function, which can be used to test the continuity of the power supply output within a certain range. The scanning test can set the scanning starting point, end point, step amount, step delay, threshold type, comparison type and other related parameters by itself, which is convenient for capturing the output characteristics of the photovoltaic system under different loads. Then, the IV characteristic curve of the photovoltaic system can be obtained through the scanning test. Generally, in order to obtain important characteristic parameters such as the open circuit voltage and short circuit current of the photovoltaic array, when the constant voltage mode is selected, the voltage starting point is set to 0V, and the end point should exceed the rated open circuit voltage of the photovoltaic array. In order to obtain more accurate IV data of the photovoltaic array, the step amount should be selected as small as possible, and in order to reduce the impact of environmental factors on the data, the step delay should be as small as possible, so that the cycle of obtaining the IV data of the photovoltaic array is short. At the same time, the electronic load tester also supports the fixed resistance mode, which can obtain the output characteristics of the photovoltaic array at a fixed working point, and then explore the impact of environmental factors on its power generation characteristics.

[0020] Compared with the prior art, the photovoltaic array data acquisition device of the present application has the following beneficial effects:

[0021] This device can collect environmental signals and electrical signals of photovoltaic arrays in real time, and can flexibly adjust the sampling frequency and resolution; it has good data collection effect, and the collection process is fast and safe, which reduces the operation and maintenance cost of photovoltaic arrays and improves the operation and maintenance efficiency.

[0022] The connection process of the entire system of the data acquisition device of this application needs to be arranged reasonably to prevent mutual interference between various electrical components. In order to make the signals collected by various physical quantities consistent in time steps, the environmental signals and electrical signals are converted into 4-20mA analog current signals to the data acquisition card. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the connection structure of the photovoltaic array data acquisition device of this application.

[0024] In the figure, 1-photovoltaic array; 2-environmental signal acquisition module; 3-voltage and current acquisition isolation module; 4-host computer module; 5-variable resistor module. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solution of the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The following embodiments are only used to illustrate the present application but are not used to limit the scope of the present application.

[0026] In the description of the present application, it should be understood that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0027] Example 1

[0028] like Figure 1 As shown, the present application proposes a photovoltaic array data acquisition device, including a photovoltaic array 1 composed of multiple photovoltaic components, and also including an environmental signal acquisition module 2, a voltage and current acquisition isolation module 3, a host computer module 4 and a variable resistor module 5. The positive and negative poles of the photovoltaic array 1 are respectively connected to the positive and negative poles of the variable resistor module 5, and the voltage and current acquisition isolation module 3 is connected in parallel with the photovoltaic array 1; the output end of the environmental signal acquisition module 2 is connected to the host computer module 4, and the output end of the voltage and current acquisition isolation module 3 is connected to the host computer module 4.

[0029] The connection process of the entire system of the data acquisition device of this application needs to be arranged reasonably to prevent mutual interference between various electrical components. In order to make the signals collected by various physical quantities consistent in time steps, the environmental signals and electrical signals are converted into 4-20mA analog current signals to the data acquisition card.

[0030] The environmental signal acquisition module 2 includes a solar radiation sensor and a thermal resistor temperature probe. Preferably, the solar radiation sensor has a range of 0-2000 W / m 2 , meeting the requirements of daily irradiance collection in most areas; the resolution is 1W / m 2 , meeting the accuracy requirements of environmental signal acquisition; the temperature measurement range of the adhesive thermal resistor is -50℃-150℃, which meets the test requirements of the photovoltaic power generation system under normal conditions. The environmental signal acquisition module 2 is used to collect real-time data of irradiance and temperature of the photovoltaic power station, convert the analog quantity into 4-20mA and connect it to the data acquisition card.

[0031] The voltage and current acquisition isolation module 3 adopts a voltage and current transmitter with a rated voltage of DC0-1000V, a rated current of DC0-100A, a rated output of DC4-20mA, a response time of less than 200ms, and an accuracy of 0.2%. The voltage and current acquisition isolation module 3 is used for real-time output voltage and current acquisition of the photovoltaic array, and converts the output voltage and current analog quantity into 4-20mA and connects it to the data acquisition card. The data acquisition card has an input port polarity protection function, an input impedance of 20MΩ (voltage), 250Ω (current), a single-ended input input mode, a precision level of 12-bit resolution, and an accuracy better than ±0.1% (one thousandth). The AD sampling rate is as high as 1MHz, and 8 channels are synchronously sampled, which can meet the requirements of collecting photovoltaic array data in a short time.

[0032] The host computer module 4 uses an 8-channel standard analog input acquisition module, an input range of 4-20mA, an AD sampling rate of 1MHz, a Modbus communication update speed of 10Hz, and a data acquisition card with a communication interface of RS485. The host computer module 4 is used to collect each 4-20mA analog signal and upload it to the PC for analysis through RS485 line transmission;

[0033] The variable resistor module 5 adopts an electronic load tester with a continuous scanning test function. The variable resistor module 5 is used to change the resistance value connected to both sides of the photovoltaic array, so as to obtain the output voltage and current of the photovoltaic array under different resistance values.

[0034] Since the voltage and current output by the photovoltaic array are not only determined by environmental factors, but also related to the size of the load connected to the photovoltaic system, in order to isolate the photovoltaic array from data acquisition systems such as microcontrollers and prevent excessive voltage and current from damaging weak electrical components, a voltage and current acquisition transmitter with isolation function is used as an electrical data acquisition element. The isolation module uses ASIC professional integrated circuits, which greatly reduces the number of components, improves circuit reliability and long-term stability, and has a response time of less than 200ms, realizing real-time current monitoring and conversion.

[0035] The device of this application uses a resistor voltage divider to connect the voltage and current acquisition isolation module to the photovoltaic array. One side is connected to the positive and negative terminals of the photovoltaic array, and the other side is connected to the host computer module after circuit isolation processing; the environmental signal acquisition module is directly connected to the host computer module, and the photovoltaic array is connected to the power grid through the convergence and inverter device, and then the electric energy is transmitted to the compressed air energy storage system. This device can be used to collect the data generated by the photovoltaic array online, including DC voltage, DC current, irradiance and temperature, which can avoid the influence of other electrical equipment on the photovoltaic power generation data, and the test results are accurate and instant. This is of great significance for process monitoring, fault diagnosis and predictive maintenance of photovoltaic power generation systems and compressed air energy storage systems.

[0036] Although the present application has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A photovoltaic array data acquisition device, comprising a photovoltaic array (1) composed of a plurality of photovoltaic modules, characterized in that: It also includes an environmental signal acquisition module (2), a voltage and current acquisition isolation module (3), a host computer module (4) and a variable resistance module (5); The environmental signal acquisition module (2) is used to collect real-time data of irradiance and temperature of the photovoltaic power station, convert the analog quantity into 4-20mA and connect it to the data acquisition card; The voltage and current acquisition isolation module (3) is used for real-time output voltage and current acquisition of the photovoltaic array, converting the output voltage and current analog quantity into 4-20mA and connecting it to a data acquisition card; The host computer module (4) is used to collect each analog signal and upload it to the PC for analysis; The variable resistor module (5) is used to change the resistance value connected to the two sides of the photovoltaic array, so as to obtain the output voltage and current of the photovoltaic array under different resistance values; The positive and negative electrodes of the photovoltaic array (1) are respectively connected to the positive and negative electrodes of the variable resistor module (5), and the voltage and current acquisition isolation module (3) is connected in parallel with the photovoltaic array (1); The output end of the environmental signal acquisition module (2) is connected to a host computer module (4), and the output end of the voltage and current acquisition isolation module (3) is connected to the host computer module (4).

2. A photovoltaic array data acquisition device according to claim 1, characterized in that: The voltage and current acquisition isolation module (3) adopts a voltage and current transmitter with a rated voltage of DC0-1000V, a rated current of DC0-100A, a rated output of DC4-20mA, a response time of less than 200ms and an accuracy of 0.2%.

3. A photovoltaic array data acquisition device according to claim 1, characterized in that: The host computer module (4) adopts an 8-channel standard analog input acquisition module, an input range of 4-20mA, an AD sampling rate of 1MHz, a Modbus communication update speed of 10Hz, and a data acquisition card with a communication interface RS485.

4. A photovoltaic power station data acquisition device according to claim 1, characterized in that: The variable resistor module (5) adopts an electronic load tester with a continuous scanning test function.

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