Photovoltaic array simulation source control method
By working together with FPGA and ARM controllers, real-time sampling and impedance conversion are achieved. Combined with a three-loop analog-digital hybrid control model, the problem of insufficient dynamic response of traditional photovoltaic analog sources is solved, achieving higher accuracy and response rate, and improving the MPPT performance of the inverter.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-11
- Publication Date
- 2026-04-03
AI Technical Summary
Traditional photovoltaic simulation sources are unable to simulate rapid weather changes and have insufficient dynamic response, which affects the test results of the inverter's maximum power point tracking performance.
The FPGA controller samples the output voltage value in real time and sends it to the ARM controller via parallel port. The ARM controller calculates the current value by looking up the table according to the preset voltage and current curve table and obtains the impedance setpoint through impedance conversion. The FPGA controller performs impedance inversion to obtain the control current value. The input is a three-loop digital-analog hybrid control model to improve the dynamic response rate.
It achieves more realistic weather simulation, improves the accuracy and dynamic response capability of photovoltaic array simulation source, reduces voltage loop delay, and improves current response rate.
Smart Images
Figure CN121785189A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of photovoltaic power generation technology, and more specifically, to a method for controlling a photovoltaic array simulated source. Background Technology
[0002] Photovoltaic power generation is a continuously attracting research hotspot in the field of new energy. Photovoltaic arrays are key components for the direct conversion of solar energy into electrical energy, and their performance directly determines the power generation efficiency and operational stability of the entire system. However, the actual output characteristics of photovoltaic arrays are extremely complex, exhibiting significant nonlinear features. The output voltage-current relationship of a photovoltaic array is dynamically affected by various environmental factors. Therefore, photovoltaic simulation sources are often used as key equipment to replace real solar photovoltaic arrays, and the accuracy of their output characteristics directly affects the test results of the inverter's maximum power point tracking performance.
[0003] Currently, most traditional photovoltaic (PV) simulation sources employ pre-generated current-voltage curve tables based on standard PV cell mathematical models, outputting corresponding current values in real-time by looking up the tables. However, their control cycle is limited by the hardware algorithm speed, making it difficult to simulate rapid weather changes and resulting in insufficient dynamic response. Furthermore, because the current-voltage curve tables are continuous nonlinear functions, the discretized points cannot fully reproduce the curve characteristics, failing to simulate the actual operating environment of PV systems and deviating significantly from real-world, highly variable weather conditions. Summary of the Invention
[0004] The problem addressed by this invention is how to improve the dynamic response rate while ensuring the accuracy of the photovoltaic array simulation source.
[0005] To address the above problems, this invention provides a photovoltaic array analog source control method, comprising: The FPGA controller obtains the output voltage value through real-time sampling and sends the output voltage value to the ARM controller via a parallel port; The ARM controller receives the output voltage value and obtains the lookup current value from a preset voltage-current curve table based on the output voltage value. The ARM controller performs impedance transformation on the lookup current value by outputting the voltage value to obtain the impedance setpoint, and then sends the impedance setpoint to the FPGA controller through the parallel port. The FPGA controller receives the impedance setpoint and reverses the impedance setpoint by outputting the voltage value to obtain the control current value. The FPGA controller inputs the output voltage and control current values into the three-loop analog-digital hybrid control model to obtain the photovoltaic array analog source control signal.
[0006] Optionally, the impedance setpoint includes: , in, Given a value for impedance, This is the voltage value from the previous table lookup. This is the output voltage value. This is the previous lookup current value. To look up the current value from the table.
[0007] Optionally, the control current value includes: , in, To control the current value, This is the previous lookup current value. This is the voltage value from the previous table lookup. This is the output voltage value. The given value is the impedance.
[0008] Optionally, the lookup current value is obtained from a preset voltage-current curve table based on the output voltage value, including: Retrieve user-defined curve model parameters; A preset voltage and current curve table is obtained based on the user-defined curve model parameters; The current value is obtained by looking up the table based on the output voltage value using a preset voltage and current curve table.
[0009] Optionally, a preset voltage and current curve table is obtained based on the user-defined curve model parameters, including: Input the user-defined curve model parameters into the standard photovoltaic cell mathematical model to obtain a preset voltage and current curve table.
[0010] Optionally, the three-loop hybrid digital-analog control model includes a digital voltage loop, a digital current loop, and an analog inner loop. The output voltage and control current values are input into the three-loop hybrid digital-analog control model to obtain the photovoltaic array analog source control signal, including: The output voltage and control current values are input into the digital voltage loop, digital current loop, and analog inner loop to obtain the photovoltaic array analog source control signal.
[0011] Optionally, the output voltage and control current values are input into the digital voltage loop, digital current loop, and analog inner loop to obtain the photovoltaic array analog source control signal, including: The first current value is obtained based on the output voltage value, control current value, and digital voltage loop. The first current value is input into the digital current loop to obtain the second current value; The second current value is input into the simulated inner loop to obtain the photovoltaic array simulated source control signal.
[0012] Optionally, the first current value is obtained based on the output voltage value, the control current value, and the digital voltage loop, including: The upper limit value of the voltage outer loop output limit is obtained based on the control current value; The digital voltage loop is updated based on the upper limit value of the voltage outer loop output limiting to obtain the updated digital voltage loop. Input the outer voltage loop setpoint and the output voltage value into the updated digital voltage loop to obtain the first current value, where the outer voltage loop setpoint is used to represent the open-circuit voltage when the current is zero.
[0013] Optionally, the first current value is input into the digital current loop to obtain the second current value, including: The output current value is obtained through real-time sampling; The output current value and the first current value are input into the digital current loop to obtain the second current value.
[0014] Optionally, the second current value is input into the analog inner loop to obtain the photovoltaic array analog source control signal, including: The second current value is converted from digital to analog and then input into the analog inner loop to obtain the photovoltaic array analog source control signal.
[0015] The beneficial effects of the photovoltaic array simulation source control method of the present invention are as follows: The FPGA controller obtains the output voltage value through real-time sampling and sends it to the ARM controller. The FPGA controller has parallel processing capabilities, which improves the dynamic response capability of the photovoltaic array simulation source, while the ARM controller has powerful general computing capabilities, which can better handle complex data. The ARM controller obtains the lookup current value from a preset voltage-current curve table based on the output voltage value, performs impedance transformation to obtain the impedance setpoint, and the FPGA controller performs impedance inversion on the impedance setpoint to obtain the control current value. This transforms the step-change lookup current value obtained from the table into a smoother current value, enabling more realistic weather simulation. The output voltage value and control current value are input into a three-loop analog-digital hybrid control model to obtain the photovoltaic array simulation source control signal. A large-proportion voltage outer loop reduces the voltage loop delay, improves the current response rate, and ensures the accuracy of the photovoltaic array simulation source. Attached Figure Description
[0016] Figure 1 This is a flowchart illustrating a photovoltaic array analog source control method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a preset voltage and current curve table according to an embodiment of the present invention; Figure 3 This is a schematic diagram of another preset voltage and current curve table according to an embodiment of the present invention; Figure 4 This is a schematic diagram of a three-loop analog-digital hybrid control model according to an embodiment of the present invention. Detailed Implementation
[0017] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.
[0018] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.
[0019] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first," "second," etc., mentioned in this invention are used only to distinguish different devices, modules, or units, and are not intended to limit the order of functions performed by these devices, modules, or units or their interdependencies.
[0020] It should be noted that the terms "a" and "a plurality of" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more". In related technologies, the Solar Array Simulator (SAS) is a key device that replaces real solar cell arrays. The accuracy of its output characteristics directly affects the test results of the inverter's maximum power point tracking (MPPT) performance. Most SAS systems use pre-generated IV curves based on standard photovoltaic cell mathematical models (such as single-diode models) and obtain the lookup current by sampling the inverter's output voltage to perform tracking control, thereby testing the inverter's MPPT tracking performance. Specifically, the required IV curve characteristic parameters (such as open-circuit voltage) are set according to a standard IV curve model (such as Sandia or EN50530). Short-circuit current Maximum power point voltage Maximum power point current Light intensity Based on the characteristic parameters of the IV curve (such as temperature parameter T), and using the mathematical model formula of the IV curve, the voltage from 0V to the open circuit is calculated in advance. The discrete voltage-current point table within the range outputs the corresponding current value in real time during operation. Each voltage point can be matched with the corresponding current value on the IV curve. By controlling the output current, the output power is changed, and the inverter gradually tracks to the maximum power point (MPPT) using a maximum power point tracking algorithm. However, the real IV curve is a continuous nonlinear function, and the discrete point table cannot completely reproduce its characteristics, especially near the MPPT, where a sparse point table amplifies simulation errors. The control cycle of the traditional lookup method is limited by the hardware algorithm speed (typically milliseconds), making it difficult to simulate rapid weather changes (such as step changes in illumination caused by cloud cover), leading to distorted dynamic MPPT efficiency test results for the inverter. Improving accuracy requires storing a high-density point table, consuming a large amount of memory, while high-frequency lookups further increase the processor load, creating a performance bottleneck.
[0021] Existing methods generally alleviate the aforementioned accuracy limitations by using interpolation algorithms or increasing the density of the lookup table. However, interpolation calculations introduce additional time delays, and expanding the lookup table increases storage pressure, further exacerbating resource consumption. Since the lookup rate is limited by controller performance, the impact of the lookup current setpoint delay is particularly pronounced in inverter testing conditions where MPPT tracking rates are constantly increasing. Currently, no existing method fundamentally resolves the contradiction between real-time performance and accuracy. The photovoltaic analog source control method, which controls the output current by looking up a pre-fabricated voltage-current lookup table, is affected by both the lookup rate and the control rate. If the lookup rate cannot be increased and the control delay is large, it will negatively impact the inverter's MPPT efficiency test results.
[0022] To address the problems existing in the aforementioned related technologies, this embodiment provides a photovoltaic array analog source control method.
[0023] like Figure 1 As shown in the figure, an embodiment of the present invention provides a photovoltaic array analog source control method, comprising: Step 110: The FPGA controller obtains the output voltage value through real-time sampling and sends the output voltage value to the ARM controller through the parallel port.
[0024] Specifically, the photovoltaic array simulation source is a nonlinear switching power supply that uses a controller to ensure that the output voltage and current conform to the photovoltaic characteristic curve. The FPGA controller performs real-time, high-frequency voltage sampling through its integrated high-speed analog-to-digital converter (ADC) to obtain the DC output voltage value of the FPGA controller at the current moment. This sampling process is executed periodically under the precise drive of the FPGA's internal clock, with sampling frequencies reaching hundreds of kilohertz or even higher, ensuring millisecond-level or even microsecond-level response capability to dynamic changes in the output voltage. After necessary filtering and calibration, the sampled digital voltage data is transmitted to the ARM controller in real time through a high-performance parallel data interface (i.e., parallel port) in a low-latency, high-throughput manner.
[0025] Step 120: The ARM controller receives the output voltage value and obtains the lookup current value from the preset voltage-current curve table based on the output voltage value.
[0026] Specifically, the preset voltage and current curve table is used to represent the pre-generated voltage and current curves obtained based on a standard photovoltaic cell mathematical model (such as a single diode model). The single diode equivalent circuit model describes the voltage-current relationship of the photovoltaic cell under different illumination and temperature conditions with high accuracy through a simplified circuit structure. When updating the model curves, the lookup table region is switched first, and the corresponding lookup current value is output based on the output voltage value.
[0027] Step 130: The ARM controller performs impedance conversion on the lookup current value using the output voltage value to obtain the impedance setpoint, and sends the impedance setpoint to the FPGA controller via the parallel port.
[0028] Specifically, the lookup current value obtained from the lookup table is impedance converted to obtain the impedance setpoint, and then sent to the FPGA controller via the parallel port.
[0029] Step 140: The FPGA controller receives the impedance setpoint and reverses the impedance setpoint by outputting the voltage value to obtain the control current value.
[0030] Specifically, the FPGA controller converts the impedance setpoint obtained from the parallel port into a control current value through impedance-current conversion. By using the impedance-current conversion formula and leveraging the high control speed of the FPGA, the output current setpoint is synchronously and rapidly changed by the high-speed change of the output voltage while the impedance remains constant during the lookup table cycle. This effectively improves the rate of change of the control current setpoint and reduces the lookup table current setpoint delay.
[0031] Step 150: The FPGA controller inputs the output voltage value and control current value into the three-ring analog-digital hybrid control model to obtain the photovoltaic array analog source control signal.
[0032] Specifically, the three-loop hybrid digital-analog control algorithm aims to further improve the control response rate and reduce the control delay from the perspective of loop control delay, based on the improvement of the control current given change rate. This algorithm is mainly implemented based on the SAS three-loop hybrid digital-analog control module, which is executed in FPGA and uses a digital voltage loop (large ratio voltage loop), a digital current loop (output current loop), and an analog inner loop (inductor current analog loop) to achieve hybrid digital-analog control.
[0033] In this embodiment, the FPGA controller obtains the output voltage value through real-time sampling and sends it to the ARM controller. The FPGA controller has parallel processing capabilities, improving the dynamic response capability of the photovoltaic array simulation source, while the ARM controller has powerful general-purpose computing capabilities, enabling better handling of complex data. The ARM controller obtains the lookup current value from a preset voltage-current curve table based on the output voltage value, performs impedance transformation to obtain the impedance setpoint, and the FPGA controller performs impedance inversion on the impedance setpoint to obtain the control current value. This transforms the step-change lookup current value obtained from the table into a smoother current value, enabling more realistic weather simulation. The output voltage value and control current value are input into a three-loop analog-digital hybrid control model to obtain the photovoltaic array simulation source control signal. A large-proportion outer voltage loop reduces the voltage loop delay, improves the current response rate, and ensures the accuracy of the photovoltaic array simulation source.
[0034] Optionally, the impedance setpoint is obtained by impedance transformation of the lookup current value using the output voltage value, including: The impedance setpoint is obtained by performing impedance transformation on the lookup current value using the output voltage value; The impedance given values include: , in, Given a value for impedance, This is the voltage value from the previous table lookup. This is the output voltage value. This is the previous lookup current value. To look up the current value from the table.
[0035] Optionally, the control current value is obtained by inverting the impedance setpoint using the output voltage value, including: The control current value is obtained by reversing the impedance setpoint using the output voltage value; The control current values include: , in, To control the current value, This is the previous lookup current value. This is the voltage value from the previous table lookup. This is the output voltage value. The given value is the impedance.
[0036] Specifically, such as Figure 2 , Figure 3 As shown, Figure 2 This is a schematic representation of the preset voltage-current curves for the existing lookup table current method. If the voltages from two consecutive lookup tables are respectively... , The corresponding currents are respectively , When the output voltage is from Change to At that time, the output current needs to be supplied by Become If the output is directly controlled by looking up a table, then the output current will be based on... Figure 2 The broken line change marked in the middle indicates that the output current is controlled first. After a duration of T, the current jumps to a new lookup table current. When the current changes abruptly, whether the preset voltage-current curve can be accurately simulated depends on the lookup rate. However, if... Figure 3 As shown, if the first lookup point ( , ) and the second lookup point ( , The straight line between two points is calculated using a formula, i.e., impedance transformation. Therefore, under the same lookup table rate, Figure 3 The solution will be better than Figure 2 If the lookup interval is minimized as much as possible, the tracking performance of the scheme can be infinitely close to the preset voltage and current curve table, thus achieving a more realistic weather simulation.
[0037] In some more specific embodiments, the highest lookup rate in the ARM controller is 10kbps, and the control rate of the FPGA controller is 500kbps. If the lookup current is directly transmitted to the FPGA controller for control, the fastest output current setting switching rate is only 10kbps, while the impedance change between adjacent points on the voltage-current curve is very small within 10kbps. If the lookup current value is converted to an impedance value, the impedance value changes at a rate of 10kbps. In the FPGA controller, the impedance value is converted to a current value. Since the FPGA controller's processing speed is 500kbps, the output voltage value... The sampling rate is 500kHz, therefore, according to impedance inversion, the output voltage value... The rate of change is 500k. The rate of change is 10k, and the control current value is calculated according to the formula. The given switching rate has also been increased to 500k.
[0038] In this optional embodiment, the output current control timing accuracy is improved by 50 times. Without increasing resources, impedance transformation effectively reduces the setpoint delay of the control loop. When the photovoltaic array simulator detects a change in output voltage, the FPGA controller can immediately change the setpoint for closed-loop control with a response rate of 500kbps. The reduced setpoint delay is beneficial for testing the inverter's MPPT performance.
[0039] Optionally, the lookup current value is obtained from a preset voltage-current curve table based on the output voltage value, including: Retrieve user-defined curve model parameters; A preset voltage and current curve table is obtained based on the user-defined curve model parameters; The current value is obtained by looking up the table based on the output voltage value using a preset voltage and current curve table.
[0040] Optionally, a preset voltage and current curve table is obtained based on the user-defined curve model parameters, including: Input the user-defined curve model parameters into the standard photovoltaic cell mathematical model to obtain a preset voltage and current curve table.
[0041] Specifically, the photovoltaic cell characteristic parameters (including but not limited to short-circuit current, open-circuit voltage, maximum power point current, maximum power point voltage under standard test conditions, as well as temperature coefficient, irradiance, ambient temperature, etc.) set by the user through the human-computer interface or host computer software are input into the system's built-in standard photovoltaic cell mathematical model. This model typically adopts a single-diode five-parameter model, establishing a nonlinear current-voltage relationship equation based on photovoltaic physics principles. The system generates a series of discrete voltage points with a set voltage step size, and for each voltage point, uses a numerical iterative algorithm (such as the Newton-Raphson method) to solve the model equation and calculate the corresponding output current value. By traversing the entire voltage range, the system generates a set of ordered voltage-current data pairs, forming a preset voltage-current curve table (LUT). This curve table accurately characterizes the static output characteristics of the photovoltaic array under the user-defined operating conditions, providing a high-precision reference benchmark for subsequent real-time lookup control, maximum power point tracking (MPPT) simulation, or dynamic response of the photovoltaic array simulation source.
[0042] Optionally, the three-loop hybrid digital-analog control model includes a digital voltage loop, a digital current loop, and an analog inner loop. The output voltage and control current values are input into the three-loop hybrid digital-analog control model to obtain the photovoltaic array analog source control signal, including: The output voltage and control current values are input into the digital voltage loop, digital current loop, and analog inner loop to obtain the photovoltaic array analog source control signal.
[0043] Optionally, the output voltage and control current values are input into the digital voltage loop, digital current loop, and analog inner loop to obtain the photovoltaic array analog source control signal, including: The first current value is obtained based on the output voltage value, control current value, and digital voltage loop. The first current value is input into the digital current loop to obtain the second current value; The second current value is input into the simulated inner loop to obtain the photovoltaic array simulated source control signal.
[0044] Optionally, the first current value is obtained based on the output voltage value, the control current value, and the digital voltage loop, including: The upper limit value of the voltage outer loop output limit is obtained based on the control current value; The digital voltage loop is updated based on the upper limit value of the voltage outer loop output limiting to obtain the updated digital voltage loop. Input the outer voltage loop setpoint and the output voltage value into the updated digital voltage loop to obtain the first current value, where the outer voltage loop setpoint is used to represent the open-circuit voltage when the current is zero.
[0045] Optionally, the first current value is input into the digital current loop to obtain the second current value, including: The output current value is obtained through real-time sampling; The output current value and the first current value are input into the digital current loop to obtain the second current value.
[0046] Optionally, the second current value is input into the analog inner loop to obtain the photovoltaic array analog source control signal, including: The second current value is converted from digital to analog and then input into the analog inner loop to obtain the photovoltaic array analog source control signal.
[0047] In some more specific embodiments, such as Figure 4 As shown, the digital voltage outer loop is given by the IV curve. Feedback is the output voltage The upper limit of the output limiting of the digital voltage outer loop is This value is equal to the control current value obtained by inverse conversion based on the impedance value. The lower limit of the output limiting of the digital voltage outer loop is... This value is equal to the reverse current limiting value, preferably -0.5A to -1A. The digital voltage outer loop uses a large proportional controller. The first current value of the digital voltage loop output is used as the input of the digital current loop. The digital current inner loop uses a PI controller, and the output value of the digital current outer loop is used as the setpoint signal for the analog inductor current inner loop. The output of the digital current loop is This value is a digital quantity and needs to be output by a DA converter as the analog input signal for the analog current inner loop.
[0048] The ingenuity of the three-loop analog-to-digital control algorithm lies in the design of the large-proportion digital voltage outer loop. This loop utilizes the characteristics of the IV curve; when the output voltage is 0, the control current is... When the output voltage is At that time, the control current is 0. That is, the voltage outer loop setpoint. The loop voltage used to represent the inductor current setpoint when the control current is zero. This represents the open-circuit current when the control voltage is zero. Before the output voltage is established after the photovoltaic analog source outputs, the output voltage feedback is 0, and the voltage loop setpoint is... According to the characteristics of IV curve At this time Under a large-scale effect, the digital voltage outer loop is in a positive saturation state, and the given value of the digital current loop is... At this time, the photovoltaic analog source control output establishes the output voltage to When the output voltage gradually increases from 0 to hour, To control the given current, which gradually decreases according to the IV curve characteristics, the decrease in the given current suppresses further voltage increases. If the output voltage is higher than... When the digital voltage loop outputs a negative current, reverse current control reduces the output voltage at the photovoltaic analog source port. This dynamic adjustment stabilizes the voltage under no-load conditions. Therefore, when the inverter has not started tracking the MPPT after the photovoltaic array analog source outputs, the photovoltaic array analog source control output voltage is always controlled at [value missing]. At the voltage level.
[0049] When the inverter starts tracking, it adjusts the output voltage according to the MPPT algorithm. Output voltage during tracking Always lower Under the influence of a large proportion, the digital voltage outer loop remains in a positive limiting state, and the output of the digital voltage outer loop is at the upper limit value. That is, the control current obtained by looking up the current from the IV curve and then performing impedance transformation and inverse transformation. At this time, the current loop is under normal closed-loop control, and the output current is tracked and controlled in real time according to the inverter port voltage and the IV curve. Through a large-proportion outer voltage loop, the voltage loop delay is reduced, thereby improving the output current control bandwidth and increasing the current response rate.
[0050] In some more specific embodiments, such as Figure 4 As shown, the ARM controller transmits the open-circuit voltage calculated by the model via a parallel port. The previous voltage value from the table lookup. The current value from the previous table lookup The data is transmitted to the FPGA. The FPGA controller then processes the open-circuit voltage obtained via the parallel port. As the voltage outer loop setpoint, the output voltage value sampled in the FPGA is used as the feedback value of the digital voltage loop. The upper limit of the digital voltage loop output is obtained by inverting the impedance setpoint using the output voltage value to obtain the control current value. The lower limit of the output limiting of the digital voltage loop is the reverse current limiting value. The first current value obtained from the digital voltage loop is used as the given current value for the digital current loop. The output current value sampled in the FPGA is used as the feedback value for the output current loop, and the limit of the output current loop is the given limit of the inductor current. The second current value is obtained from the input digital current loop and output through the DA module as the given value for the inductor current analog inner loop. The control output of the inductor current analog inner loop is used as the drive signal for the actual switching transistor, obtaining the photovoltaic array analog source control signal for actual power control, thus completing the closed-loop control.
[0051] In this optional embodiment, the conventional lookup table current is first converted into an impedance value, and then the impedance value is converted back into a control current setpoint in the FPGA. By utilizing the high computing speed of the FPGA, the rate of change of the setpoint current is increased. At the same time, the control setpoint current value output by the lookup table current impedance algorithm is used as the upper limit of the large-proportion voltage outer loop in the three-loop analog-digital control algorithm. Through the large-proportion voltage outer loop, the voltage loop delay is reduced, thereby improving the output current control bandwidth and increasing the current response rate.
[0052] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.
Claims
1. A photovoltaic array analog source control method, characterized in that, include: The FPGA controller obtains the output voltage value through real-time sampling and sends the output voltage value to the ARM controller via a parallel port; The ARM controller receives the output voltage value and obtains the lookup current value from a preset voltage-current curve table based on the output voltage value. The ARM controller performs impedance conversion on the lookup current value using the output voltage value to obtain an impedance setpoint, and sends the impedance setpoint to the FPGA controller via a parallel port. The FPGA controller receives the impedance setpoint and reverses the impedance setpoint using the output voltage value to obtain the control current value. The FPGA controller inputs the output voltage value and the control current value into the three-loop analog-digital hybrid control model to obtain the photovoltaic array analog source control signal.
2. The photovoltaic array analog source control method according to claim 1, characterized in that, The impedance given value includes: ， in, Given a value for the impedance, This is the voltage value from the previous table lookup. The output voltage value is... This is the previous lookup current value. The current value is the one obtained from the table lookup.
3. The photovoltaic array analog source control method according to claim 1, characterized in that, The control current value includes: ， in, The control current value, This is the previous lookup current value. This is the voltage value from the previous table lookup. The output voltage value is... The impedance is given a value.
4. The photovoltaic array analog source control method according to claim 1, characterized in that, The step of obtaining the lookup current value from a preset voltage-current curve table based on the output voltage value includes: Retrieve user-defined curve model parameters; The preset voltage and current curve table is obtained based on the user-defined curve model parameters; The lookup current value is obtained from the preset voltage and current curve table based on the output voltage value.
5. The photovoltaic array analog source control method according to claim 4, characterized in that, The step of obtaining the preset voltage and current curve table based on the user-defined curve model parameters includes: The preset voltage and current curve table is obtained by inputting the user-defined curve model parameters into the standard photovoltaic cell mathematical model.
6. The photovoltaic array analog source control method according to claim 1, characterized in that, The three-loop hybrid digital-analog control model includes a digital voltage loop, a digital current loop, and an analog inner loop. The step of inputting the output voltage value and the control current value into the three-loop hybrid digital-analog control model to obtain the photovoltaic array analog source control signal includes: The output voltage value and the control current value are input into the digital voltage loop, the digital current loop and the analog inner loop to obtain the photovoltaic array analog source control signal.
7. The photovoltaic array analog source control method according to claim 6, characterized in that, The step of inputting the output voltage value and the control current value into the digital voltage loop, the digital current loop, and the analog inner loop to obtain the photovoltaic array analog source control signal includes: The first current value is obtained based on the output voltage value, the control current value, and the digital voltage loop; The first current value is input into the digital current loop to obtain the second current value; The second current value is input into the simulated inner loop to obtain the photovoltaic array simulated source control signal.
8. The photovoltaic array analog source control method according to claim 7, characterized in that, The step of obtaining the first current value based on the output voltage value, the control current value, and the digital voltage loop includes: The upper limit value of the voltage outer loop output limit is obtained based on the control current value; The digital voltage loop is updated based on the upper limit value of the output limiting of the outer voltage loop to obtain the updated digital voltage loop; The outer voltage loop setpoint and the output voltage value are input into the updated digital voltage loop to obtain the first current value, wherein the outer voltage loop setpoint is used to represent the open-circuit voltage when the current is zero.
9. The photovoltaic array analog source control method according to claim 8, characterized in that, The step of inputting the first current value into the digital current loop to obtain the second current value includes: The output current value is obtained through real-time sampling; The output current value and the first current value are input into the digital current loop to obtain the second current value.
10. The photovoltaic array analog source control method according to claim 9, characterized in that, The step of inputting the second current value into the analog inner loop to obtain the photovoltaic array analog source control signal includes: The second current value is converted from digital to analog and then input into the analog inner loop to obtain the photovoltaic array analog source control signal.