System and method for photovoltaic i-v curve tracking using electronic load

Abstract

A system includes a measurement module, an industrial I / O extension module, an SBC module, and a user interface module. The measurement module provides a platform for connection with the photovoltaic panel module for measurement of current and voltage. The measuring module comprises a voltage sensor, a current sensor and an MOSFET. The photovoltaic panel module and the current sensor are connected in series, and the series combination of the photovoltaic panel module and the current sensor is connected in parallel with the voltage sensor and the MOSFET. And the industrial I / O expansion module is coupled with the measurement module and is used for converting the analog signal into a digital signal. The SBC module obtains a current reading and a voltage reading from the measurement module through the industrial I / O expansion module. A user interface module is coupled with the SBC module and provides a user interface to allow a user to operate the measurement process.

Description

Technical Field

[0001] The present invention generally relates to photovoltaic IV curve tracking technology. More specifically, the present invention provides systems and methods related to photovoltaic IV curve tracking using electronic loads. Background Art

[0002] In terms of characterizing photovoltaic (PV) panels, its core technology involves plotting IV (current-voltage) and PV (power-voltage) curves of PV panels. These curves provide a comprehensive view of the performance of the panel under different conditions, including key parameters such as open circuit voltage, short circuit current, and maximum power point. By analyzing these curves, the efficiency and suitability of PV panels in different scenarios can be determined, making this curve plotting technology indispensable in both research and practical applications of solar energy systems.

[0003] There are six basic methods to measure the IV curve of a PV panel: using a variable resistor, a capacitive load, an electronic load, a bipolar power amplifier, a four-quadrant power supply, and a DC-DC converter. Each method has different advantages and can be selected based on the required requirements.

[0004] For example, a variable resistor may be chosen for ease of use and cost effectiveness, while an electronic load may be ideal for precise control and detailed performance analysis. Capacitive loads are useful for dynamic testing, while bipolar power amplifiers are also considered for their ability to handle current sourcing and current sinking. Four-quadrant power supplies are relatively flexible and can operate in all four quadrants of the IV space diagram, supporting a variety of test conditions. DC-DC converters are necessary in scenarios that require efficient power management and conversion, ensuring that the PV panel operates near its maximum power point.

[0005] Therefore, the choice of method to be used will depend on the accuracy, complexity and specific test requirements. Therefore, it is necessary to optimize the measurement method to be able to comprehensively cover the IV curve characteristics of the PV panel. Summary of the invention

[0006] The purpose of the present invention is to provide a device and a method to solve the above problems existing in the prior art.

[0007] According to one aspect of the present invention, a system for photovoltaic IV curve tracing is provided, comprising a measurement module, an industrial I / O expansion module, a single board computer (SBC) module, and a user interface module. The measurement module provides a platform for connecting a photovoltaic (PV) panel module to perform current and voltage measurements using an electronic load, wherein the measurement module comprises a voltage sensor, a current sensor, and a metal oxide semiconductor field effect transistor (MOSFET) used as the electronic load, the photovoltaic panel module and the current sensor are connected in series, and the series combination of the photovoltaic panel module and the current sensor is connected in parallel with the voltage sensor and the MOSFET. The industrial I / O expansion module is coupled to the measurement module and configured to convert an analog signal into a digital signal. The SBC module is configured to obtain current readings and voltage readings from the measurement module through the industrial I / O expansion module. The user interface module is coupled to the SBC module and configured to provide a user interface that allows at least one user to operate the measurement process and obtain visual measurement results.

[0008] According to one aspect of the present invention, a method for setting up a photovoltaic IV curve tracking system is provided. The method includes the following steps: providing a measurement module, providing a platform for connecting a photovoltaic (PV) panel module to perform current and voltage measurements using an electronic load, wherein the measurement module includes a voltage sensor, a current sensor, and a metal oxide semiconductor field effect transistor (MOSFET) used as the electronic load; connecting the photovoltaic panel module and the current sensor in series; connecting the series combination of the photovoltaic panel module and the current sensor in parallel with the voltage sensor and the MOSFET; coupling an industrial I / O expansion module with the measurement module to convert an analog signal into a digital signal; coupling a single board computer (SBC) module with the industrial I / O expansion module so that the SBC module can obtain current readings and voltage readings from the measurement module through the industrial I / O expansion module; and coupling a user interface module with the SBC module so that the user interface module can provide a user interface that allows at least one user to operate a measurement process and obtain a visual measurement result.

[0009] According to one aspect of the present invention, a method for tracking a photovoltaic IV curve is provided, which comprises the following steps: providing the system as described above; and displaying the visualized measurement results, which include graphs of the IV curve and the PV curve of the photovoltaic panel module.

[0010] With the above configuration, the system of the present invention uses MOSFET as an electronic load for measurement, because linear MOSFET operates under the action of a scanning signal with a low frequency and a large enough amplitude, so that the IV characteristic range of the photovoltaic panel can be fully covered. The basic principle of the measurement is to use the Raspberry Pi 4B as a central processing unit (CPU) to send signals to adjust the gate-source voltage (VGS) of the MOSFET while obtaining current and voltage readings from the sensor. Between the Raspberry Pi and the measurement circuit, the Raspberry Pi's industrial automation I / O card can complete the conversion of analog signals into digital signals. In order to facilitate the display of measurement progress and results, a graphical user interface (GUI) was also developed using PyQt5. The portability and flexibility of the model adopted make it suitable for educational purposes, so that it can be used as a research and educational tool and used to demonstrate the generation process of IV curves. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Embodiments of the present invention will be described in more detail with reference to the accompanying drawings, in which:

[0012] Figure 1 A schematic diagram of a system architecture for photovoltaic IV curve tracking in an embodiment of the present invention is presented;

[0013] Figure 2 A schematic diagram of the architecture of a measurement module in an embodiment of the present invention is shown;

[0014] Figure 3 A circuit diagram of the measurement principle of the measurement module in an embodiment of the present invention is shown;

[0015] Figure 4 The characteristic diagram of the photovoltaic panel module under standard test conditions (STC) and the characteristic diagram of MOSFET in the embodiment of the present invention are shown;

[0016] Figure 5A A wiring configuration diagram of a voltage sensor in an embodiment of the present invention is shown;

[0017] Figure 5B A circuit diagram of a voltage sensor in an embodiment of the present invention is shown;

[0018] Figure 6 A circuit connection configuration diagram of a current sensor in an embodiment of the present invention is shown;

[0019] Fig. 7A A schematic diagram of an N-channel MOSFET in an embodiment of the present invention is shown;

[0020] Figure 7B The output characteristic diagram of the MOSFET in the embodiment of the present invention when TC=25°C is shown;

[0021] Figure 7C A MOSFET circuit diagram in an embodiment of the present invention is shown;

[0022] Figure 8 The present invention uses a sawtooth wave as a scanning signal to generate V GS Schematic diagram of

[0023] Fig. 9A A schematic diagram of a power supply in an embodiment of the present invention is shown;

[0024] Fig. 9B A filter circuit diagram of an AC / DC converter in an embodiment of the present invention is shown;

[0025] Fig. 9C A filter circuit diagram of a DC / DC converter in an embodiment of the present invention is shown;

[0026] Fig.10 A flow chart of a measurement algorithm in an embodiment of the present invention is shown;

[0027] Fig.11 A schematic diagram of a PyQt5-based GUI for a photovoltaic panel during IV curve measurement according to an embodiment of the present invention is shown;

[0028] Fig. 12A shows a GUI example of a complete IV curve and PV curve in manual mode; and

[0029] Fig. 12B A GUI example graph of a complete IV curve and PV curve in automatic mode is shown. DETAILED DESCRIPTION

[0030] In the following description, systems and methods for photovoltaic IV curve tracking using electronic loads, etc. will be used as preferred examples. Those skilled in the art will appreciate that modifications, including additions and / or substitutions, may be made without departing from the scope and spirit of the invention. Specific details may be omitted so as not to obscure the invention; however, the present disclosure is written to enable those skilled in the art to practice the teachings herein without undue experimentation.

[0031] Figure 1 The schematic diagram of the architecture of a system 100 for photovoltaic IV curve tracing according to an embodiment of the present invention is depicted. The system 100 includes a measurement module 110, an industrial I / O expansion module 120, a single-board computer (SBC) module 130, and a user interface module 140.

[0032] The measurement module 110 provides a platform for connecting a photovoltaic (PV) panel module to perform current and voltage measurements using an electronic load. The industrial I / O expansion module 120 is coupled to the measurement module 110 and is used to convert analog signals into digital signals. The SBC module 130 is configured to obtain current and voltage readings from the measurement module 110 through the industrial I / O expansion module 120, thereby enabling programmatic control of the measurement process. The user interface module 140 is coupled to the SBC module 130 and provides a user interface that allows a user to operate the measurement process and obtain visual measurement results. The following description will further explain each module.

[0033] Figure 2 1 is a schematic diagram of the structure of the measurement module 110 according to an embodiment of the present invention. The measurement module 110 includes a voltage sensor 112, a current sensor 114, and a metal-oxide-semiconductor field-effect transistor (MOSFET) 116 as an electronic load. The photovoltaic IV curve tracking measurement operation can be performed on the photovoltaic panel module 102, wherein the photovoltaic panel module 102 is connected in series with the current sensor 114, and the series combination is connected in parallel with the voltage sensor 112 and the MOSFET 116, so that the voltage sensor 112 and the MOSFET 116 are also connected in parallel.

[0034] In this regard, Figure 3 A circuit diagram of the measurement principle of the measurement module 110 according to an embodiment of the present invention is shown; Figure 4 The characteristic diagram of the photovoltaic panel module and the characteristic diagram of MOSFET under standard test conditions (STC) according to the embodiment of the present invention are shown.

[0035] exist Figure 3 In the diagram of FIG. 1 , in order to explain the measurement principle, a basic circuit for testing a photovoltaic panel module (e.g., a photovoltaic panel module or string) by using a MOSFET as an electronic load is provided. The MOSFET has a drain coupled to the anode of the photovoltaic panel module and a source coupled to the cathode of the photovoltaic panel module. The MOSFET has a gate used as a control terminal. For the MOSFET, V GS is the gate-source voltage, V DS is the drain-source voltage, I D is the drain current. V PV is the output voltage of the photovoltaic panel module, I PV is the output current, I SC is the short-circuit current, V OC is the open circuit voltage.

[0036] exist Figure 4 In the diagram, they are D -V DS The graph of the curves shows the characteristics of the MOSFET (see the solid curve), each of which corresponds to a specific gate-source voltage (V GS ). The figure also shows the I PV -V PV The characteristic curve of the photovoltaic module and the characteristic curve of the MOSFET at a specific voltage V GS The operating point (OP) is determined by applying an appropriate signal to sweep V GS , the operating point of the MOSFET can be PV -V PV On the curve, from the open circuit voltage (V OC ) scans to the short-circuit current (I SC ). As long as the MOSFET's V GS Below the threshold voltage (V th ), it will remain in the off state. GS Exceed V th When the photovoltaic panel module can operate within its working area, I D or I PV Will follow V GS It shows an almost linear increase.

[0037] Regarding photovoltaic panel modules, Figure 2 When the voltage shown exceeds the maximum power point voltage (V MPP ) region, the voltage V PV For current (I PV ) will have slight fluctuations, and V GS The rapid movement of the operating point in this region can be attributed to its high sensitivity, so it is necessary to generate a suitable scanning signal to generate V GS Voltage.

[0038] From the above, it can be seen that it is feasible to use MOSFET for photovoltaic IV curve tracking, which can track the photovoltaic IV curve of the photovoltaic panel module on the voltage-current characteristic diagram. In addition, based on the measurement principle described in this article, the following will provide the selected hardware configuration and software settings to achieve a flexible and portable measurement platform.

[0039] Reference again Figure 2, which shows a measurement circuit to measure the voltage directly at the output end of the photovoltaic panel module 102. Through the architecture of the measurement module 110, the measurement performed can accurately present the actual working process of the photovoltaic panel module 102. In one embodiment, the photovoltaic panel module 102 uses a silicon single crystal SPV module (e.g., M010-12V). Table I shows the photovoltaic panel module 102 under standard test conditions (STC, irradiance: 1000W / m 2 , module temperature: 25°C, AM=1.5) electrical specifications. Table I: Electrical and mechanical characteristics of photovoltaic modules (M010-12V) at STC

[0040] In one embodiment, the voltage sensor 112 may be a LEM voltage sensor to quantify the voltage; in this regard, the LEM LV 25-P is a voltage sensor 112 that utilizes the Hall effect principle. The sensed voltage and the signal output may be separated by electrical isolation. The voltage sensor 112 is capable of measuring voltage levels up to 600V. Figure 5A A wiring configuration diagram of a voltage sensor 112 according to an embodiment of the present invention is shown. The voltage sensor 112 is capable of measuring AC voltage and DC voltage, which requires a balanced power input. The current output of the voltage sensor 112 depends on the voltage detected at its input terminal. By connecting the resistor terminal connected to the undervoltage side of the voltage sensor 112 to any analog input terminal of the microcontroller, the voltage connected to this resistor terminal can be conveniently measured, thereby facilitating the measurement of the input voltage.

[0041] In one embodiment, the measurement module 110 further includes a power supply voltage source for the voltage sensor 112, and the power supply provided by the power supply voltage source is within the range of ±15V. In order to limit the current before the current is input to the voltage sensor 112, the measurement module 110 further includes a sensing resistor (R SENSE ) 150. The process of determining the appropriate sensing resistor includes dividing the maximum sensing voltage (equivalent to the open circuit voltage of the photovoltaic panel) by the current of 10mA. 10mA is the nominal current root mean square (IPN) of the voltage sensor 112 based on the tolerance requirement. In some embodiments, considering that the voltage level does not exceed 24V, the limiting value of the sensing resistor is:

[0042] A fixed resistor of 1.5 kΩ can be selected as R SENSE(ie, for sensing resistor 150). The output of voltage sensor 112 is current. However, the ADC module only reads the voltage signal and not the current signal. In one embodiment, the measurement module 110 also includes a grounding resistor (denoted as R M ), which is located at the output end and its purpose is to convert the current into a corresponding voltage signal. According to the data sheet, R M The voltage resistance can be selected to be 100Ω. In some embodiments, the circuit diagram of the voltage sensor 112 of the LV 25-P is as follows: Figure 5B , which shows a circuit diagram of the voltage sensor 112 according to an embodiment of the present invention.

[0043] Since the turns ratio of the voltage sensor 112 of the LEM LV25-P is 2500:1000, the measured voltage (U m ) and input voltage (U in ) is:

[0044] In one embodiment, by SENSE =1500Ω and R M =100Ω Substituting into the above formula, U m and U in The relationship between them is: U (# =6×U *

[0045] Therefore, if Figure 5B As shown, the voltage sensor 112 is connected to the SENSE Coupled to the negative voltage electrode of the photovoltaic panel module 102 and connected to the negative voltage electrode of the photovoltaic panel module 102 through a 100Ω R M Coupled to ground.

[0046] Figure 6 A circuit connection configuration diagram of a current sensor 114 according to an embodiment of the present invention is shown. In one embodiment, the current sensor 114 may use a CTSR 0.6-P sensor manufactured by LEM for current sensing. This is a closed-loop current sensor with high operating accuracy and minimal offset drift in response to temperature changes. The measurement range of the current sensor 114 is ±850mA, the maximum sensitivity error is 0.7%, and the linearity error is 0.4%-1.3%. The current sensor 114 can measure DC, AC, and pulse currents, wherein the primary circuit and the secondary circuit of the current sensor 114 can be separated by electrical isolation.

[0047] exist Figure 6 In the diagram, U c The output of the current sensor 114 is a voltage, which is marked as Vout。 In some embodiments, the ref The potential can be a floating potential. In order to improve the accuracy of current measurement, two turns of the photovoltaic panel output cable can be selected, and its sensitivity is 0.48V / 100mA, that is, 4.8V / A. The internal reference voltage of the current sensor 114 is 2.5V. Therefore, the following formula for calculating the current of the photovoltaic panel can be obtained:

[0048] Fig. 7A FIG. 1 shows a schematic diagram of an N-channel MOSFET of MOSFET 116 according to an embodiment of the present invention. In one embodiment, MOSFET 116 uses an N-channel MOSFET as an electronic load, such as IRF510. In this regard, for MOSFET 116, its gate-source voltage (V GS ) has a range of ±20V, and the maximum drain-source voltage (V DS ) is 100V. At 25°C, the continuous drain current (I D ) is limited to 5.6A, while at a temperature of 100°C the continuous drain current (ID) is limited to 4.0A.

[0049] Figure 7B The MOSFET 116 according to the embodiment of the present invention is shown in FIG. C =25℃ output characteristic diagram. In the figure, it can be seen that for V less than 5V GS value, the corresponding I D In one embodiment, assuming that the short-circuit current (I SC ) is 0.57A, then the gate-source voltage (V GS ) in order to measure / track the IV curve of a PV panel.

[0050] Figure 7C 1 shows a circuit diagram of a MOSFET 116 according to an embodiment of the present invention. Since the drain contact can be attached to the metal surface of the package in the MOSFET 116, the MOSFET 116 can be electrically isolated and mounted on a suitable heat sink. In one embodiment, the gate G and source S of the MOSFET 116 can be connected in parallel with a 100 kΩ resistor and are commonly coupled to a gate-source voltage source V GS (Gate G is coupled to a gate-source voltage source, and source S is coupled to a ground potential terminal.) A 100uF capacitor may be connected in parallel to drain D and source S of MOSFET 116, and then connected to Vpanel+ and Vpanel- (i.e., the positive and negative terminals of the photovoltaic panel), respectively.

[0051] Figure 8 The present invention uses a sawtooth wave as a scanning signal to generate V GS Schematic diagram of the reference Figure 1 and Figure 8 As described above, the voltage sensor 112 and the current sensor 114 may use LV 25-P and CTSR 0.6-P sensors to measure voltage and current. In one embodiment, the SBC module 130 uses a Raspberry Pi 4B to process digital signals. In this regard, the voltage and current sensors may pose challenges when working because they generate analog signals, and the Raspberry Pi can only process digital signals.

[0052] To solve this problem, the industrial I / O expansion module 120 uses the industrial automation I / O card of Raspberry Pi, which provides four analog inputs with a range of 0-10V or ±10V, and four analog outputs with a range of 0-10V. The communication protocol used in the interface between the industrial I / O expansion module 120 and the SBC module 130 is the I2C (Inter Integrated Circuit) protocol.

[0053] During operation, the industrial I / O expansion module 120 can collect 0-10V or ±10V analog input data from the voltage sensor 112 and the current sensor 114 of the measurement module 110. Figure 8 As shown, the 0-10V analog output of the industrial I / O expansion module 120 can generate a sawtooth wave with a voltage range of 3-5V, which can be used as a sweep signal to generate V GS (gate-source voltage).

[0054] The industrial I / O expansion module 120 will first send out a sweep signal through a 0-10V analog output, which generates a 3-5V V for the MOSFET 116 of the measurement module 110. GS , and the step size is 0.01V. In one embodiment, the voltage step size is adjustable during encoding. In this way, a total of 2000 V GS Value, each V GS The values ​​correspond to a pair of data points (current I, voltage V) of the photovoltaic panel (i.e., photovoltaic panel module 102). The voltage and current data are transmitted to the 0-10V or ±10V analog input of the industrial I / O expansion module 120. The SBC module 130 (e.g., Raspberry Pi 4B) is used as a microprocessor computer, which can be used to act as a CPU and for data logging, data storage, and curve drawing. The user interface module 140 can be a laptop computer for display.

[0055] The system 100 also includes a power supply 142 . Fig. 9A A schematic diagram of a power supply 142 according to an embodiment of the present invention is shown. In the power supply 142, its power circuit is connected to an AC / DC converter 144 (e.g., model Mean Well RD-50A), which can convert 88-264VAC to isolated 5VDC and 12VDC. The SBC module 130 (Raspberry Pi) and the current sensor 114 (CTSR 0.6-P) can use the 5VDC output, while the 12VDC output is used by the DC / DC converter 146 (e.g., TEN 5-1223), which can provide a ±15V voltage source for the voltage sensor 112 (LV 25-P). In addition, the industrial I / O expansion module requires a 24V power supply 148 (e.g., model TCL 060-124).

[0056] Fig. 9B A filtering circuit diagram of the AC / DC converter 144 according to an embodiment of the present invention is shown. In one embodiment, before the AC / DC converter 144 is connected to the measurement module 110, the output voltage of the AC / DC converter 144 can be filtered. Fig. 9B In the illustration of , labels X1-1, X1-2, X1-3, and X1-4 are connectors respectively connected to the +Vout1 terminal, the GND terminal, the +Vout2 terminal, and the GND terminal of the AC / DC converter 144. These labels are a kind of fuse for protecting the circuit. Fig. 9C The filter circuit diagram of the DC / DC converter 146 according to the embodiment of the present invention is shown. For the same reason, in one embodiment, a filter circuit is optionally designed for the DC / DC converter 146, whose output voltage is ±15V and supplies power to the voltage sensor 112.

[0057] Fig.10 A flow chart of a measurement algorithm according to an embodiment of the present invention is shown. Code combination can be performed to facilitate the operation process of the measurement. In this regard, a graphical user interface (GUI) can be generated, and the measurement progress and results can be displayed through the user interface module 140 to provide a good user experience. In one embodiment, PyQt5 is a collection of Python applications written in Python language, and uses the graphical program framework Qt5. These applications are compatible with the Linux operating system and can be executed on the SBC module 130 (Raspberry Pi). The PyQt framework provides a series of tools that can create a user interface and enable the user interface to interact with SQL databases, 2D and 3D graphics, network communications, multimedia and other functions.

[0058] Fig.11 A schematic diagram of a PyQt5-based GUI during IV curve measurement of a photovoltaic panel according to an embodiment of the present invention is shown. In one embodiment, the PyQt5-based GUI can be displayed to the user through the user interface module 140. For example, the user can see the following Fig.11 The measurement control has two modes, manual mode and automatic mode. When the "Manual" button in the manual mode is turned on, the user can adjust V by manipulating the slider within the range of 0 (i.e. 3V) to 100% (i.e. 5V). GS When the "Auto" button is turned on, V GS It can be modified automatically, where the value step and time step can be set by the "vStep" and "tStep" functions in the user interface module 140, respectively. In one embodiment, the values ​​of these parameters are vStep=0.01V, tStep=0.2s, where increasing the value of vStep or decreasing the value of tStep can increase the drawing speed. The button "Redo" can clear and redraw the curve. The "Export" button can export the current and voltage values ​​to a CSV document. When the "Clear" button is pressed, all content will be deleted from the user interface module 140. In addition, the settings in the lower left corner can modify the numerical range of the coordinate axis. With this configuration, combined with the system 110 as described above, the IV curve and PV curve of the photovoltaic panel module 102 can be drawn. In one embodiment, the user interface module 140 is also configured to display visualized measurement results, including graphs with IV curves and PV curves of the photovoltaic panel module 102. For example, Fig. 12A is an example diagram showing a GUI with a complete IV curve and PV curve displayed in manual mode; and Fig. 12B is an example of a GUI showing the complete IV and PV curves displayed in automatic mode. Figure 4 Similar to the illustration in FIG. 1 , the characteristic curves of MOSFET 116 at different gate-source voltages are also presented on the graph to help the user better understand the composition or structure of the obtained IV curve and PV curve.

[0059] Compared to the device that tests the IV characteristic curve of a photovoltaic panel using a capacitor and processes the data using a Raspberry Pi and AnalogDiscovery 2, since the capacitor can only be charged and discharged continuously, this means that the drawing of the IV curve cannot be interrupted. Therefore, the curve drawing process cannot be better demonstrated. Under the condition that the capacitor stores charge, when the voltage across the capacitor changes, it will cause a transient response, that is, a temporary flow of current. This transient behavior can complicate the interpretation of the IV curve, especially if the measurement setup does not take these transients into account. To accurately test the IV curve of the capacitor, the time factor must also be considered. The capacitor takes time to charge and discharge, and the IV curve also changes according to the rate of voltage change. This makes the test process more complicated and time-consuming. When using a capacitor, the magnitude of the current depends on the rate of change of the voltage (dV / dt). This makes it challenging to accurately control the current value and leads to less accurate and non-repeatable measurements. In addition, the analog-to-digital converter Analog Discovery 2 is also more expensive than the industrial automation card.

[0060] Compared with the device that chooses Arduino as the CPU to process data, the present invention uses Raspberry Pi to draw IV (current-voltage) curves. In comparison, the technical solution of the present invention has several advantages over using Arduino. Compared with Arduino, Raspberry Pi has a more powerful processor. This means that Raspberry Pi can perform complex calculations and data processing more efficiently. Since drawing IV curves involves reading analog data from sensors, processing it, and drawing curves, it may require a lot of calculations. In this regard, the higher processing power of Raspberry Pi ensures smoother and faster data processing. Raspberry Pi can run on mature operating systems (usually based on Linux), and the system can provide access to a variety of programming languages, databases, and tools. This makes it easier to develop, debug, and modify the code for drawing IV curves. On the other hand, Arduino uses its specific IDE and programming language, which may have some limitations on data processing and drawing. Raspberry Pi has built-in connection options such as Ethernet, Wi-Fi, and USB ports. This allows users to easily transfer data to external devices, store data remotely, and even upload it to the cloud for further analysis. Although Arduino is able to connect to sensors, it may require additional modules or shields to enable similar connection options. The Raspberry Pi can be connected to a variety of displays and has better graphics capabilities than the Arduino. This makes the system better suited for real-time visualization of IV curves on a display or graphical interface. The Arduino is more focused on microcontroller functions and may not offer the same level of graphics capabilities. The Raspberry Pi typically has more storage options than most Arduinos, either through an SD card or onboard memory. This allows you to store more data and try different data logging avenues when plotting IV curves.

[0061] The functional units and modules of the processor and method according to the embodiments disclosed herein can be implemented in the form of hardware or software. That is to say, the required processor can be implemented completely as a machine instruction or as a combination of machine instructions and hardware elements. Hardware elements include, but are not limited to, computing devices, computer processors, or electronic circuits, including but not limited to application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), microcontrollers, and other programmable logic devices configured or programmed according to the teachings of this disclosure. Those skilled in the art of software or electronics can easily prepare computer instructions or software codes running in computing devices, computer processors, or programmable logic devices based on the teachings of this disclosure.

[0062] The system may include computer storage media, transient and non-transitory memory devices having computer instructions or software codes stored therein, which may be used to program or configure a computing device, a computer processor, or an electronic circuit to perform any of the processes of the present invention. The storage media, transient and non-transitory memory devices may include, but are not limited to, floppy disks, optical disks, Blu-ray disks, DVDs, CD-ROMs, magneto-optical disks, ROMs, RAMs, flash memory devices, or any type of medium or device suitable for storing instructions, codes, and / or data.

[0063] The system may also be configured as a distributed computing environment and / or cloud computing environment, where all or part of the machine instructions are executed in a distributed manner by one or more processing devices interconnected by a communication network, such as an intranet, a wide area network (WAN), a local area network (LAN), the Internet, and other forms of data transmission media.

[0064] The above description of the present invention is provided for the purpose of illustration and description. It is not intended to be exhaustive or to limit the present invention to the precise form disclosed. For those skilled in the art, many modifications and variations will be apparent.

[0065] The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use contemplated.

Claims

1. A system for photovoltaic IV curve tracking, characterized in that: include: Measurement module, provided for connecting photovoltaic A platform for photovoltaic (PV) panel modules to perform current and voltage measurements using an electronic load, wherein the measurement module includes a voltage sensor, a current sensor, and a metal-oxide-semiconductor field-effect transistor (MOSFET) used as the electronic load, the photovoltaic panel module and the current sensor are connected in series, and the series combination of the photovoltaic panel module and the current sensor is connected in parallel with the voltage sensor and the MOSFET; an industrial I / O expansion module coupled to the measurement module and configured to convert the analog signal into a digital signal; a single-board computer (SBC) module configured to obtain current readings and voltage readings from the measurement module through the industrial I / O expansion module; as well as The user interface module is coupled to the SBC module and is configured to provide a user interface that allows at least one user to operate the measurement process and obtain a visualized measurement result.

2. The system according to claim 1, characterized in that The MOSFET has a gate coupled to a gate-source voltage source and a source coupled to a ground potential terminal, wherein the measurement module further includes a 100 kΩ resistor connected in parallel with the gate and the source of the MOSFET.

3. The system according to claim 2, characterized in that The MOSFET has a drain coupled to the positive electrode of the photovoltaic panel module, and the source of the MOSFET is coupled to the negative electrode of the photovoltaic panel module, wherein the measurement module also includes a 100uF capacitor, and the drain and source of the MOSFET are connected in parallel with the capacitor.

4. The system according to claim 1, characterized in that The MOSFET has a gate-source voltage range of ±20V and a maximum drain-source voltage of 100V, and its continuous drain current is limited to 5.6A at 25°C and 4.0A at 100°C.

5. The system according to claim 1, characterized in that The MOSFET is an N-channel MOSFET.

6. The system according to claim 1, characterized in that The measurement module further includes a sensing resistor of 1500Ω and a grounding resistor of 100Ω, and the voltage sensor is coupled to the negative voltage electrode of the photovoltaic panel module through the sensing resistor, and is coupled to the ground potential terminal through the grounding resistor.

7. The system according to claim 1, characterized in that The industrial I / O expansion module uses an industrial automation I / O card, which provides four analog inputs with a range of 0-10V or ±10V, and provides four analog outputs with a range of 0-10V.

8. The system according to claim 7, characterized in that The industrial I / O expansion module is also configured to collect 0-10V or ±10V analog input data from the voltage sensor and the current sensor of the measurement module, and the industrial I / O expansion module is also configured to generate a sawtooth wave with a voltage range of 3-5V and use it as one or more scanning signals to generate a gate-source voltage of the MOSFET.

9. The system according to claim 8, characterized in that The industrial I / O expansion module is further configured to generate the scanning signal with a step length of 0.01V for the MOSFET.

10. The system according to claim 1, characterized in that The user interface module is also configured to: Displaying the visualized measurement results includes drawing a graph of the IV curve and the PV curve of the photovoltaic panel module, wherein in the graph there is a characteristic curve of the MOSFET at different gate-source voltages.

11. A method for setting up a photovoltaic IV curve tracking system, characterized in that: include: Provides measurement modules for connecting photovoltaic A platform for a photovoltaic (PV) panel module to perform current and voltage measurements using an electronic load, wherein the measurement module includes a voltage sensor, a current sensor, and a metal-oxide-semiconductor field-effect transistor (MOSFET) used as the electronic load; connecting the photovoltaic panel module and the current sensor in series; connecting the series combination of the photovoltaic panel module and the current sensor in parallel with the voltage sensor and the MOSFET; coupling an industrial I / O expansion module with the measurement module to convert the analog signal into a digital signal; coupling a single board computer (SBC) module to the industrial I / O expansion module so that the SBC module can obtain current readings and voltage readings from the measurement module through the industrial I / O expansion module; and A user interface module is coupled to the SBC module so that the user interface module can provide a user interface that allows at least one user to operate a measurement process and obtain a visualized measurement result.

12. The method according to claim 11, characterized in that The MOSFET has a gate coupled to a gate-source voltage source and a source coupled to a ground potential terminal, wherein the measurement module further includes a 100 kΩ resistor connected in parallel with the gate and the source of the MOSFET.

13. The method of claim 12, wherein the MOSFET has a drain coupled to the positive electrode of the photovoltaic panel module, the source of the MOSFET is coupled to the negative electrode of the photovoltaic panel module, wherein the measurement module further comprises a capacitor of 100uF, and the drain and the source of the MOSFET are connected in parallel with the capacitor.

14. The method according to claim 11, characterized in that The measurement module further includes a sensing resistor of 1500Ω and a grounding resistor of 100Ω, and the voltage sensor is coupled to the negative voltage electrode of the photovoltaic panel module through the sensing resistor, and is coupled to the ground potential terminal through the grounding resistor.

15. The method according to claim 11, characterized in that The industrial I / O expansion module uses an industrial automation I / O card, which provides four analog inputs with a range of 0-10V or ±10V, and provides four analog outputs with a range of 0-10V.

16. A method for photovoltaic IV curve tracking, characterized in that: include: Providing the system according to claim 1; as well as The visualized measurement results are displayed, including graphs of the IV curve and the PV curve of the photovoltaic panel module.

17. The method according to claim 16, characterized in that Displaying the visualized measurement result includes displaying characteristic curves of the MOSFET at different gate-source voltages on the graph.

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