Photovoltaic MPPT dual-mode disturbance control method and system, medium and terminal

Abstract

The invention relates to the technical field of photovoltaic MPPT control, in particular to a photovoltaic MPPT dual-mode disturbance control method and system, a medium and a terminal. The control method comprises the following steps: a data acquisition and calculation step: acquiring parameters of the photovoltaic module in real time and calculating a voltage variation, a current variation, a power variation and a step length adjustment factor; step length judgment and adjustment: judging whether the original maximum step length value is restored after multiple disturbances are performed under the condition of increasing the maximum step length value according to the power variation and the relation of the product obtained by a preset proportionality coefficient # imgabs0 # and the real-time power value, so as to determine the corresponding step length; and a duty ratio adjustment step: judging whether the real-time voltage of the photovoltaic module at the current moment is in a preset voltage interval containing the voltage value corresponding to the maximum power point so as to carry out different duty ratio adjustment. Through the arrangement, the energy loss of a traditional variable step size perturbation and observation method is reduced, and the convergence speed and the dynamic response speed are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic MPPT control, and particularly relates to a photovoltaic MPPT dual-mode perturbation control method, system, medium, and terminal. Background Art

[0002] In a photovoltaic system, it is crucial to effectively utilize the maximum power of a photovoltaic cell. According to the maximum power transfer theorem, when the load resistance is equal to the internal resistance of the power supply, the load can obtain the maximum power. Therefore, it is necessary to adopt the maximum power point tracking (MPPT, Maximum Power Point Tracking) technology to ensure that the photovoltaic cell always operates near the maximum power point.

[0003] The traditional variable step size perturbation and observation method is one of the commonly used MPPT methods, but this method has obvious defects. If the maximum step size is set too large, it will cause the algorithm to converge prematurely, resulting in large steady-state oscillations. In particular, when the light condition or temperature condition changes, the traditional variable step size perturbation and observation method is prone to misjudgment problems, which will reduce the power and cause energy loss. Its misjudgment will cause the working point after forced change to deviate from the maximum power point, slowing down the convergence speed.

[0004] Therefore, how to improve the photovoltaic MPPT control technology to reduce the problems such as large energy loss, slow convergence speed, and poor dynamic response speed existing in the traditional variable step size perturbation and observation method has become a key problem in current photovoltaic control research. Summary of the Invention

[0005] To solve at least one deficiency in the existing photovoltaic MPPT control in the above-mentioned prior art, the present invention provides a photovoltaic MPPT dual-mode perturbation control method to reduce the energy loss of the traditional variable step size perturbation and observation method and improve the convergence speed and dynamic response speed.

[0006] In the first aspect, the photovoltaic MPPT dual-mode perturbation control method provided by the present invention includes the following steps: Data acquisition and calculation step, real-time acquisition of the current real-time voltage and real-time current of the photovoltaic module, calculation of the voltage change amount at the current moment relative to the current change amount and power change amount at the moment, and calculation of the step size adjustment factor Step size judgment and adjustment step, according to the power change amount and the preset proportional coefficient Determine whether to perform multiple perturbations after increasing the maximum step value and then restore to the original maximum step value based on the relationship between the product of the real-time power value and the corresponding step to determine the corresponding step ; Duty cycle adjustment step, determine the current real-time voltage at the moment of the photovoltaic module Whether it is within a preset voltage range including the voltage value corresponding to the maximum power point; if the real-time voltage of the current photovoltaic module is within the preset voltage range, then according to the voltage change Positive and negative conditions and the corresponding step Adjust the duty cycle; if the real-time voltage of the current photovoltaic module is not within the preset voltage range, then according to the power change , voltage change , current change Positive and negative conditions and the corresponding step Adjust the duty cycle.

[0007] In a second aspect, the present invention also provides a photovoltaic MPPT dual-mode perturbation control system, including: Data acquisition and calculation module, which acquires the real-time voltage and real-time current of the photovoltaic module at the current moment in real time, calculates the voltage change , current change at the current moment relative to the moment, and power change , and calculates the step adjustment factor ; ; Step judgment and adjustment module, used to judge whether to perform multiple perturbations after increasing the maximum step value and then restore to the original maximum step value based on the relationship between the power change and the product of the preset proportional coefficient and the real-time power value to determine the corresponding step[[ID= fifty]] ; Duty cycle adjustment module, used to judge the current real-time voltage of the photovoltaic module at the moment; if the real-time voltage of the current photovoltaic module is within the preset voltage range, then according to the voltage change Positive and negative conditions and the corresponding step Adjust the duty cycle; if the real-time voltage of the current photovoltaic module is not within the preset voltage range, then according to the power change , voltage change , current change [[ID= sixty-seven]]Positive and negative conditions and the corresponding step Adjust the duty cycle.

[0008] In a third aspect, the present invention further provides a storage medium, which is a non-volatile storage medium or a non-transient storage medium, on which a computer program is stored. When the computer program is run by a processor, it executes the photovoltaic MPPT dual-mode perturbation control method described in any one of the embodiments of the first aspect above.

[0009] In a fourth aspect, the present invention further provides a terminal, characterized in that it includes a memory and a processor. A computer program capable of running on the processor is stored on the memory. When the processor operates the computer program, it executes the photovoltaic MPPT dual-mode perturbation control method described in any one of the embodiments of the first aspect above.

[0010] Based on the above, compared with the prior art, the photovoltaic MPPT dual-mode perturbation control method provided by the embodiment of the present invention determines whether to perform multiple perturbations when increasing the step value by judging the power change amount through the step size judgment and adjustment step, so as to effectively improve the dynamic response speed while preventing the steady-state oscillation amplitude from being too large; it also designs a duty cycle adjustment step to add a new perturbation logic, that is, to adjust the duty cycle by determining whether the voltage is within a preset voltage range including the voltage value corresponding to the maximum power point, so as to effectively converge quickly and avoid large steady-state oscillations even when the maximum step size is set large.

[0011] Other features and beneficial effects of the present invention will be described in the subsequent description, and some of them will become obvious from the description or be understood by implementing the present invention. The objectives and other beneficial effects of the present invention can be achieved and obtained through the structures specifically pointed out in the description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts; in the following description, the positional relationships in the drawings, unless otherwise specified, are based on the directions shown by the components in the drawings.

[0013] Figure 1 It is a control flowchart of the traditional variable step size perturbation observation method; Figure 2 It is a schematic diagram of the working point movement trajectory of the traditional variable step size perturbation observation method; Figure 3 It is a working point movement trajectory diagram of the traditional variable step size perturbation observation method under light change; Figure 4 It is the working point movement trajectory diagram of the traditional variable step size perturbation observation method under temperature change; Figure 5 It is the step flow chart of the photovoltaic MPPT dual-mode perturbation control method provided by an embodiment of the present invention; Figure 6 It is the control flow chart of the photovoltaic MPPT dual-mode perturbation control method provided by an embodiment of the present invention; Figure 7 It is the working point movement trajectory diagram of the improved algorithm and the traditional algorithm when crossing the maximum power point; Figure 8 It is the working point movement trajectory diagram of the improved algorithm and the traditional algorithm when not crossing the maximum power point; Figure 9 It is the working point movement trajectory diagram of the improved algorithm and the traditional algorithm under light intensity change; Figure 10 It is the schematic diagram of the Simulink simulation model; Figure 11 It is the schematic diagram of setting light intensity change when the temperature is fixed; Figure 12 It is the power output waveform diagram of the improved algorithm and the traditional algorithm under light intensity change conditions; Figure 13 It is the schematic diagram of setting temperature change when the light is fixed; Figure 14 It is the power output waveform diagram of the improved algorithm and the traditional algorithm under temperature change conditions; Figure 15 It is the structural block diagram of the photovoltaic MPPT dual-mode perturbation control system provided by another embodiment of the present invention. Detailed implementation manners

[0014] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention; the technical features designed in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0015] In the description of the present invention, it should be noted that all terms used in the present invention (including technical terms and scientific terms) have the same meanings as those commonly understood by those of ordinary skill in the technical field to which the present invention pertains, and should not be construed as limiting the present invention; it should be further understood that the terms used in the present invention should be understood as having meanings consistent with their meanings in the context of this specification and the relevant fields, and should not be understood in an idealized or overly formal sense, unless otherwise clearly defined in the present invention.

[0016] Currently, the most commonly used control method for photovoltaic MMPT control technology adopts the variable step-size perturbation observation method. Its core objective is to make the photovoltaic cell always work as close as possible to the maximum power point under different environmental conditions such as light intensity and temperature, so as to improve the power generation efficiency of the photovoltaic system; specifically, it uses the slope of the operating point to adjust the step size and continuously adjusts the operating point of the photovoltaic cell (usually by changing the duty cycle), observes the change of power, and as the operating point gets closer to the maximum power point, its slope gets closer to 0, that is, gradually approaching the maximum power point.

[0017] For example Figure 1 Shown is the control flow chart of the traditional variable step-size perturbation observation method. When controlling according to this traditional variable step-size perturbation observation method, if the maximum step size is set relatively large, it will cause the algorithm to converge prematurely, and then lead to large steady-state oscillations. For example Figure 2 As shown, when the operating point moves from point A to point B, since at this time and are both greater than 0, logically it should continue to perturb to the right, resulting in a decrease in power, and then return from point C to point B, and then back to point A, cycling repeatedly among the three points.

[0018] For example Figure 3 As shown, when the photovoltaic module is in an environment with decreasing light intensity, the operating point moves from point D to point E. At this time and are both less than 0, and the algorithm will correctly perturb to the right. However, when the photovoltaic module is in an environment with increasing light intensity, since at this time and are both greater than 0, the traditional algorithm will continue to perturb to the right once, and the operating point moves from point B to point C. This perturbation will cause a decrease in power, which is a misjudgment that the traditional algorithm cannot avoid. This misjudgment behavior will cause energy loss and is also a key factor affecting the convergence speed of the traditional algorithm. Due to this misjudgment behavior, the forcedly changed operating point will deviate from the maximum power point, slowing down its convergence speed.

[0019] For example Figure 4As shown, when the photovoltaic module is in an environment with rising temperature, the operating point is similar to that in an environment with decreasing light intensity, and the algorithm is normally perturbed. However, when the photovoltaic module is in an environment with decreasing temperature, the operating point moves from point A to point B. At this time and are both greater than 0. Similar to the environment with increasing light intensity, the algorithm will be perturbed to the right to point C due to misjudgment, resulting in power reduction.

[0020] Therefore, when the maximum step size of this traditional perturbation observation method with variable step size is set relatively large, it may cause the algorithm to converge prematurely, resulting in large steady-state oscillations. It may also cause misjudgment when the light intensity or temperature changes, resulting in energy loss and affecting the convergence speed. That is, it faces the balance problem between the maximum step size and steady-state oscillations, and it is difficult to satisfy both fast convergence speed and small steady-state oscillations simultaneously.

[0021] In view of the significant deficiencies of the above technologies, such as large energy loss, slow convergence speed, and poor dynamic response speed, the present invention provides a dual-mode perturbation control method for photovoltaic MPPT based on region constraint and power change detection to effectively solve the above problems. That is, by adding two new perturbation logics to the traditional perturbation observation method with variable step size, the energy loss of the traditional perturbation observation method with variable step size is reduced, and the convergence speed and dynamic response speed are improved.

[0022] The technical solutions of the present invention will be described and explained in detail through various specific implementation manners in combination with different embodiments and the accompanying drawings of the specification.

[0023] Embodiment 1 Please refer to Figure 5 、 Figure 6 The dual-mode perturbation control method for photovoltaic MPPT provided in this embodiment includes the following steps: Step S10, data acquisition and calculation step, real-time acquisition of the current real-time voltage and real-time current of the photovoltaic module at the th moment, calculation of the voltage change amount 、current change amount and power change amount 、 at the th moment relative to the th moment, and calculation of the step size adjustment factor Specifically, at each sampling moment, a voltage sensor and a current sensor are used to respectively collect the real-time voltage and real-time current of the photovoltaic module. After obtaining the real-time voltage and real-time current of the photovoltaic module at the th moment, according to the formula Calculate the real-time power ; then calculate the current time relative to the time voltage change , current change and power change formulas are respectively: , , ; where is the real-time voltage at the time, is the real-time current at the time, is the real-time power at the time.

[0024] Calculate the step size adjustment factor formula is: . Among them, the step size adjustment factor is used to dynamically adjust the step size so that the step size can be flexibly changed according to the changes of power and voltage to more efficiently and accurately track the maximum power point, where the step size adjustment factor can be adjusted according to the actual power change and voltage change.

[0025] Step S20, step size judgment and adjustment step, according to the power change and the product obtained from the preset proportional coefficient and the real-time power value to judge whether to perform multiple perturbations and then restore to the original maximum step size value when increasing the maximum step size value to determine the corresponding step size .

[0026] Specifically, when implemented, according to the power change and the product obtained from the preset proportional coefficient and the real-time power value, it should be judged whether or is established; if it is established, then perform perturbations, and the corresponding step size is set to , wait for perturbations to end, and the corresponding step size is adjusted to ; if it is not established, then do not perform perturbations, and the corresponding step size is adjusted to ; in the formula, , are the maximum step size values, and , is the step size proportional coefficient.

[0027] In the above embodiments, whether the light or temperature changes significantly is determined by comparing the power change amount with the power values before and after the light change. If , it indicates that the light or temperature has increased significantly. If , it indicates that the light or temperature has decreased significantly. After determining that the light has changed significantly, the maximum step value is increased to perform multiple perturbations, that is, the maximum step value is set to , and the corresponding step size is adjusted to . Through the above step size adjustment method, the operating point can quickly approach the maximum power value and accelerate the dynamic response speed. Among them, the number of perturbations is set, that is, after perturbations are completed, the maximum step value is adjusted to the original , and the corresponding step size is adjusted to the original . This set number of times can avoid increasing the oscillation amplitude, and the specific number of times can be reasonably set according to actual needs.

[0028] It should be noted that the value of the preset proportionality coefficient can be reasonably designed according to the actual light intensity change or temperature change requirements; similarly, , , can also be reasonably set according to the actual working condition requirements, and this embodiment does not limit them here.

[0029] Step 30, the duty cycle adjustment step, determines whether the real-time voltage of the current moment of the photovoltaic module is within a preset voltage range including the voltage value corresponding to the maximum power point; if the real-time voltage of the current photovoltaic module is within the preset voltage range, the duty cycle is adjusted according to the positive and negative conditions of the voltage change amount and the corresponding step size ; if the real-time voltage of the current photovoltaic module is not within the preset voltage range, the duty cycle is adjusted according to the positive and negative conditions of the power change amount , the voltage change amount , the current change amount and the corresponding step size .

[0030] Specifically, when implementing, a preset voltage range including the voltage value corresponding to the maximum power point is first set. For example, the preset voltage range is set to . The setting range of this interval can be obtained through multiple tests and analyses of the characteristic curve of the photovoltaic module, and then it is determined whether the real-time voltage at the current moment is within this preset interval.

[0031] Specifically, it is determined whether the current Real-time voltage at a moment Whether it is within the set interval That is, judge Whether it holds. In the formula, 、 Are set interval coefficients, 、 The values of respectively satisfy Less than the voltage value corresponding to the maximum power point, Greater than the voltage value corresponding to the maximum power point, Is the open-circuit voltage of the photovoltaic module. It should be noted that 、 The values of should be reasonably adjusted according to actual needs. For example, according to experience, the voltage value corresponding to the maximum power point should be 0.8 times the open-circuit voltage of the photovoltaic module. Therefore, here we can design 、 For example 、 .

[0032] If the real-time voltage At the current Of the photovoltaic module is within the set interval Then judge whether the count value Satisfies ; If it is satisfied, adjust the duty cycle according to the positive and negative conditions of the voltage change amount And the corresponding step size , And let ; If it is not satisfied, adjust the duty cycle according to the positive and negative conditions of the power change amount , Voltage change amount , Current change amount And the corresponding step size , And let .

[0033] If the real-time voltage At the current Of the photovoltaic module is not within the set interval Then adjust the duty cycle according to the positive and negative conditions of the power change amount , Voltage change amount , Current change amount And the corresponding step size , And let .

[0034] Among them, the steps to adjust the duty cycle according to the positive and negative conditions of the voltage change amount And the corresponding step size Are as follows: Judge whether the voltage change amount Satisfies , if satisfied, the duty cycle at the nth moment is adjusted to , if not satisfied, the duty cycle at the nth moment is adjusted to ; According to the power change , voltage change , current change of the positive and negative situations and the corresponding step size , the steps to adjust the duty cycle are: Judge whether the power change meets , judge whether the voltage change meets , judge whether the current change meets ; If all of , , or all of , or all of , are satisfied, then the duty cycle at the nth moment is adjusted to ; if all of , , or all of , are satisfied, then the duty cycle at the nth moment is adjusted to .

[0035] Through the above adjustment of the duty cycle, a new perturbation logic strategy is adopted during the perturbation process, that is, after a perturbation is performed according to the logic of the traditional algorithm (i.e., the traditional variable step size perturbation observation method), a perturbation opposite to the logic of the traditional algorithm will be performed. When the new perturbation strategy is adopted when not crossing the maximum power point, it will lead to a decrease in the convergence speed. Therefore, this embodiment sets a preset voltage range, that is, the new perturbation logic strategy is enabled only when it is determined that the current voltage is within the preset voltage range. Since the operating point is close to the maximum power point within this preset voltage range, it is very likely that the maximum power point will be crossed. If a perturbation strategy of alternating the traditional algorithm logic and the new perturbation logic is adopted within this preset voltage range, it is possible to use a larger maximum step size value while achieving fast convergence and avoiding large steady-state oscillations.

[0036] Furthermore, it further includes step S40, the parameter update and loop step, to update the voltage, current, power and duty cycle and perform the next loop calculation to continue the perturbation until the maximum power point is tracked.

[0037] In the parameter update and loop steps, the formulas for updating voltage, current, power, and duty cycle respectively include: , , , . That is, the real-time voltage, real-time current, real-time power, and duty cycle of the photovoltaic module at the current moment are updated to the real-time voltage, real-time current, real-time power, and duty cycle of the previous moment, so as to be used in the next cycle calculation and provide accurate data basis for subsequent step size adjustment and duty cycle adjustment. Specifically, the above relevant parameters can be stored and updated through registers in a microprocessor or a controller.

[0038] The above process of loop calculation and continuous perturbation will continue until the system tracks the maximum power point of the photovoltaic module. In practical applications, a judgment condition can be set to determine whether the maximum power point has been tracked. For example, a threshold of the power change amount can be set. When the power change amount obtained from consecutive loop calculations is less than this threshold

[0039] This embodiment realizes the innovation and optimization of the photovoltaic MPPT control strategy through the above steps. Specifically, through the step size judgment and adjustment step, the power change amount is judged to determine whether, after multiple perturbations with the maximum step size value increased, it returns to the original maximum step size value, so as to effectively improve the dynamic response speed while preventing the steady-state oscillation amplitude from being too large; also, through the design of the duty cycle adjustment step, new judgment conditions and new perturbation logic strategies are added to reduce misjudgment, that is, the duty cycle is adjusted by determining that the voltage is within a preset voltage range including the voltage value corresponding to the maximum power point, so as to effectively converge quickly and avoid large steady-state oscillations even when the maximum step size is set large.

[0040] To effectively illustrate the effect principle of the photovoltaic MPPT dual-mode perturbation control method provided in this embodiment, as an example, taking the working point crossing the maximum power point from left to right, the preset voltage range for enabling the new perturbation logic strategy is set to , and the movement trajectory of the working point after crossing the maximum power point (MPP) using the control method (i.e., the improved algorithm) provided in this embodiment is as Figure 7 shown. After crossing the maximum power point, the working point will move from point B to point D. Then, due to and , the algorithm will continue to perturb leftward to point E. Compared with the working point of the traditional algorithm moving from point B to point C, the convergence speed is significantly improved, and the energy loss is reduced. If the maximum power point is not crossed within the preset voltage range, the overall moving direction of the working point will still point to the maximum power point, and the moving trajectory is as Figure 8 shown. After the working point moves from point A to point B, it will move to point C due to reverse perturbation, and then cross the maximum power point and move to point D. In short, at this time, due to the perturbation logic, the algorithm naturally corrects the working point to the working point where the next perturbation will cross the maximum power point (MPP), and then the moving trajectory of the working point will be the same as Figure 7 shown.

[0041] Taking a significant increase in light intensity as an example, when the light changes, due to , that is, the power change amount is greater than times the power value before the light change, it indicates that the light amplitude has increased significantly. At this time, the improved algorithm of this embodiment will increase the maximum step value to make the algorithm converge quickly, and restore the original maximum step value after a certain number of perturbations to ensure that the steady-state oscillation amplitude will not increase. As Figure 9 shown, due to the misjudgment behavior of the traditional algorithm, the working point will move from point B to point C, because at this time and are both greater than 0. While using the improved algorithm provided in this embodiment, the movement of the working point will be opposite to that of the traditional algorithm, that is, it will move from point B to point D, and then the movement of the working point and Figure 7 and Figure 8 are similar, and it will move to point E and point F, and the convergence speed will be faster than that of the traditional algorithm. Similarly, the moving trajectory of the working point when the temperature decreases is similar to that when the light intensity increases, and the convergence speed of the improved algorithm provided in this embodiment is also faster than that of the traditional algorithm.

[0042] To further illustrate the effect of the above photovoltaic MPPT dual-mode perturbation control method, this embodiment also conducts a simulation test. Specifically, as Figure 10As shown in the figure, a photovoltaic maximum power tracking simulation model is built in MATLAB / Simulink, which mainly includes a photovoltaic module, an MPPT controller, PWM (Pulse Width Modulation), a DC / DC converter and a load. Among them, the photovoltaic module is connected to the load through a DC / DC converter, which is used to convert the direct current generated by the photovoltaic module from light energy into electrical energy into a stable direct current with different voltages through the DC / DC converter and act on the load; the photovoltaic module inputs scene signals simulating light intensity and temperature conditions, and at the same time, the real-time voltage and real-time current are also collected. The DC / DC converter adopts a Boost converter, and the load is a resistor with a resistance value of 100Ω. The MPPT controller is connected to the DC / DC converter through PWM to make the solar panel work at the maximum power point, so as to make full use of solar energy resources and improve the energy conversion efficiency of the system. Among them, the MPPT controller continuously detects the changes in the current and voltage of the photovoltaic array, and adjusts the duty cycle of the PWM drive signal of the DC / DC converter according to the changes, and then adjusts the equivalent resistance of the DC / DC converter to always be equal to the internal resistance of the photovoltaic module, so as to achieve the maximum output of the photovoltaic module, make full use of the solar cell, and make it operate at the maximum power point. The MPPT controller uses the improved algorithm provided in this embodiment to adjust the duty cycle.

[0043] Based on the above simulation model, when the temperature is fixed at 25°C, the light intensity is set as Figure 11 shown. The maximum step values of both the traditional algorithm and the improved algorithm in this embodiment are set to 0.002, and the step ratio coefficients are both set to 1. The improved maximum step value in the improved algorithm of this embodiment is set to 0.02, the number of perturbation times is set to 60, the preset ratio coefficient is set to 2, the set interval coefficient is set to 0.75, and the set interval coefficient is set to 0.85.

[0044] Based on the above settings and simulations, the power output waveforms of the traditional algorithm and the improved algorithm under changing light conditions can be obtained as Figure 12 shown. When the initial light intensity is 300W / m 2 , the improved algorithm converges at 0.016s, and the traditional algorithm converges at 0.018s with an oscillation amplitude significantly greater than that of the improved algorithm. After the light intensity suddenly changes to 1000W / m 2 , the improved algorithm converges at 0.052s, and the traditional algorithm oscillates significantly due to the excessive step size. When the light intensity returns to 300W / m 2After that, the improved algorithm converges in 0.102 s, while the traditional algorithm converges in 0.104 s. The oscillation amplitude is also significantly larger than that of the improved algorithm. It can be seen from this that the improved algorithm not only has a faster convergence speed than the traditional algorithm when the light intensity remains unchanged, but also has a faster dynamic response speed when the light intensity changes, and has a smaller oscillation amplitude under the same maximum step size setting.

[0045] When the light is fixed at 1000 W / m 2 , the temperature change is as Figure 13 shown. The maximum step sizes of the traditional algorithm and the improved algorithm are both set to 0.0005, and the proportionality coefficients are both set to 1. The of the improved algorithm is set to 0.02, is set to 60, is set to 2.

[0046] Based on the above settings, the power output waveforms of the traditional algorithm and the improved algorithm under the condition of temperature change are as Figure 14 shown. When the initial temperature is 25 °C, the improved algorithm converges in 0.006 s, and the traditional algorithm converges in 0.04 s. After the temperature suddenly changes to 15 °C, the improved algorithm converges in 0.053 s, and the traditional algorithm converges in 0.064 s. After the temperature suddenly changes to 45 °C, the improved algorithm converges in 0.111 s, and the traditional algorithm oscillates significantly due to the too large step size. It can be seen from this that the improved algorithm has a faster convergence speed and dynamic response speed than the traditional algorithm under the condition of temperature change, and can avoid large-amplitude oscillation under the same maximum step size setting.

[0047] Therefore, the performance of the photovoltaic MPPT dual-mode perturbation control method (i.e., the improved algorithm) provided in this embodiment is better than that of the traditional variable step size perturbation observation method (i.e., the traditional algorithm) under the conditions of light and temperature changes.

[0048] In summary, the photovoltaic MPPT dual-mode perturbation control method provided by the embodiments of the present invention adopts a dual-mode perturbation control strategy based on region constraint and power change detection to solve the balance problem between the maximum step size and steady-state oscillation faced by the traditional variable step size perturbation observation method, as well as the problem that it is difficult to simultaneously meet the requirements of fast convergence speed and small steady-state oscillation. Specifically, in the mode based on power change detection, the power change amount is judged through the step size judgment and adjustment steps to determine whether to restore to the original maximum step size value after multiple perturbations under the condition of increasing the maximum step size value, so as to effectively improve the dynamic response speed while preventing the steady-state oscillation amplitude from being too large; in the mode based on region constraint, the duty cycle adjustment step is designed to add new judgment conditions and perturbation logic strategies to reduce misjudgment, that is, the duty cycle is adjusted by determining whether the voltage is within a preset voltage range including the voltage value corresponding to the maximum power point, so as to effectively converge quickly and avoid large steady-state oscillation even when the maximum step size is set large.

[0049] Embodiment 2 Please refer to Figure 15 , the embodiments of the present invention also provide a photovoltaic MPPT dual-mode perturbation control system, which at least includes: A data acquisition and calculation module, configured to acquire the real-time voltage and real-time current of the photovoltaic module at the current moment in real time, calculate the voltage change amount at the current moment relative to the moment, the current change amount , and the power change amount , and calculate the step size adjustment factor ; ; A step size judgment and adjustment module, configured to judge whether to restore to the original maximum step size value after multiple perturbations under the condition of increasing the maximum step size value according to the power change amount and the product obtained from the preset proportional coefficient and the real-time power value, so as to determine the corresponding step size ; A duty cycle adjustment step, configured to judge whether the real-time voltage of the photovoltaic module at the current moment is within a preset voltage range including the voltage value corresponding to the maximum power point; if the real-time voltage of the current photovoltaic module is within the preset voltage range, the duty cycle is adjusted according to the positive and negative conditions of the voltage change amount and the corresponding step size ; if the real-time voltage of the current photovoltaic module is not within the preset voltage range, the duty cycle is adjusted according to the power change amount , the voltage change amount , and the current change amount Positive and negative conditions and corresponding step sizes Adjust the duty cycle.

[0050] Furthermore, the photovoltaic MPPT dual-mode perturbation control system further includes a parameter update and loop module, which is used to update voltage, current, power, and duty cycle and perform the next loop calculation to continue perturbation until the maximum power point is tracked.

[0051] This system has significant effects in improving the performance of the photovoltaic system, enhancing environmental adaptability, optimizing system stability, etc. The specific ways for each module in the above-mentioned Embodiment 2 to perform operations have been described in detail in Embodiment 1 of the related method, and will not be elaborated here.

[0052] Embodiment 3 The embodiment of the present invention further provides a storage medium, which is a non-volatile storage medium or a non-transient storage medium, on which a computer program is stored, and when the computer program is run by a processor, it executes the photovoltaic MPPT dual-mode perturbation control method described in any one of the above embodiments.

[0053] Specifically, the storage medium is a magnetic disk, an optical disk, a read-only memory (ROM), a random access memory (RAM), a flash memory, a hard disk drive (HDD), or a solid-state drive (SSD), etc.; the storage medium may also include a combination of the above types of memories.

[0054] Embodiment 4 The embodiment of the present invention further provides a terminal, which includes a memory and a processor. A computer program capable of running on the processor is stored on the memory, and when the processor operates the computer program, it executes the photovoltaic MPPT dual-mode perturbation control method described in any one of the above embodiments.

[0055] In specific implementation, the number of processors can be one or more. The processor can be a central processing unit (CPU). The processor can also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc., or a combination of the above types of chips. The general-purpose processor can be a microprocessor or any conventional processor, etc.

[0056] The memory and the processor can be communicatively connected through a bus or other means. The memory stores program instructions executable by at least one processor. The program instructions are executed by at least one processor to enable the processor to execute the photovoltaic MPPT dual-mode perturbation control method described in any of the foregoing embodiments.

[0057] In addition, those skilled in the art should understand that although there are many problems in the prior art, each embodiment or technical solution of the present invention can be improved in only one or several aspects, and it is not necessary to solve all the technical problems listed in the prior art or the background art at the same time. Those skilled in the art should understand that the content not mentioned in a claim should not be used as a limitation to the claim.

[0058] Although terms such as data acquisition and calculation steps, step size judgment and adjustment steps, duty cycle adjustment steps, parameter update and loop steps, etc. are used more frequently herein, the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitation is contrary to the spirit of the present invention; the terms "first", "second", etc. (if any) in the specification and claims of the embodiments of the present invention and the above drawings are used to distinguish similar objects and do not necessarily need to be used to describe a specific order or sequence.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A photovoltaic MPPT dual-mode perturbation control method, characterized in that Including the following steps: Data acquisition and calculation steps, real-time acquisition of the current real-time voltage at the and real-time current , calculate the current time relative to the time voltage change , current change and power change , and calculate the step adjustment factor ; Step size judgment and adjustment step, according to the power change amount and the relationship of the product obtained by the preset proportional coefficient and the real-time power value to judge whether to restore to the original maximum step size value after multiple perturbations when increasing the maximum step size value, and determine the corresponding step size ; Duty cycle adjustment step, determine the current instantaneous voltage of the photovoltaic module; whether it is within a preset voltage range including the voltage value corresponding to the maximum power point; if the instantaneous voltage of the current photovoltaic module is within the preset voltage range, then adjust the duty cycle according to the positive or negative situation of the voltage change amount and the corresponding step size ; if the instantaneous voltage of the current photovoltaic module is not within the preset voltage range, then adjust the duty cycle according to the positive or negative situation of the power change amount , the voltage change amount , the current change amount and the corresponding step size .

2. The photovoltaic MPPT dual-mode perturbation control method according to claim 1, wherein: The data acquisition and calculation steps specifically include: Obtain the real-time voltage at the moment, and the real-time current . According to the formula , calculate the real-time power ; Then calculate the voltage change at the current moment relative to the voltage change, current change and power change are given by the following formulas: , , ; The formula for calculating the step size adjustment factor is: .

3. The photovoltaic MPPT dual-mode perturbation control method according to claim 1, wherein: The step size judgment and adjustment steps specifically include: Judge or Whether it holds; if it holds, perform times of perturbation, and the corresponding step size is set to , wait After the times of perturbation end, the corresponding step size is adjusted to ; if it does not hold, do not perform times of perturbation, and the corresponding step size is adjusted to ; where , is the maximum step size value, and , is the step size proportionality coefficient.

4. The photovoltaic MPPT dual-mode perturbation control method according to claim 1, wherein: The duty cycle adjustment steps specifically include: Determine the current real-time voltage of the photovoltaic module at the moment, that is, determine whether the real-time voltage is within the set interval , that is, determine whether holds. In the formula, , are the set interval coefficients, and the , values respectively satisfy is less than the voltage value corresponding to the maximum power point, is greater than the voltage value corresponding to the maximum power point, and is the open-circuit voltage of the photovoltaic module.

5. The photovoltaic MPPT dual-mode perturbation control method according to claim 4, wherein: The duty cycle adjustment steps specifically further include: If the real-time voltage of the photovoltaic module at the current moment is within the set interval , then judge whether the count value meets ; if it meets, then adjust the duty cycle according to the positive and negative conditions of the voltage change and the corresponding step , and let ; if it does not meet, then adjust the duty cycle according to the positive and negative conditions of the power change , the voltage change , the current change and the corresponding step , and let ; If the current real-time voltage at a certain moment of the photovoltaic module is not within the set range , then according to the positive and negative conditions of the power change , voltage change , current change and the corresponding step size , adjust the duty cycle, and let .

6. The photovoltaic MPPT dual-mode perturbation control method according to claim 5, characterized in that: According to the positive or negative condition of the voltage change amount and the corresponding step size The steps for adjusting the duty cycle are as follows: Determine the voltage change amount whether it satisfies . If it satisfies, the duty cycle at the nth moment is adjusted to . If it does not satisfy, the duty cycle at the nth moment is adjusted to ; According to the power change amount , voltage change amount , current change amount of the positive and negative conditions and the corresponding step size The steps to adjust the duty cycle are as follows: Judge the power change amount Whether it meets 、Judge the voltage change amount Whether it meets 、Judge the current change amount Whether it meets ; If the following conditions are met simultaneously , , or the following conditions are met simultaneously , or the following conditions are met simultaneously , , then the duty cycle at the nth moment is adjusted to ; if the following conditions are met simultaneously , , or the following conditions are met simultaneously , , then the duty cycle at the nth moment is adjusted to .

7. The photovoltaic MPPT dual-mode perturbation control method according to claim 1, characterized in that: It further includes parameter update and loop steps, updating voltage, current, power and duty cycle and performing the next cycle calculation to continue perturbation until tracking to the maximum power point; In the parameter update and loop steps, the formulas for updating voltage, current, power, and duty cycle respectively include: , , , .

8. A photovoltaic MPPT dual-mode perturbation control system, characterized in that Including: A data acquisition and calculation module for real-time acquisition of the current instantaneous voltage and instantaneous current of the photovoltaic module, calculating the voltage change at the current instant relative to the instant, current change and power change , and calculating a step size adjustment factor ; A step size judgment and adjustment module, which is used to determine whether to restore to the original maximum step size value after multiple perturbations when increasing the maximum step size value according to the power change amount and the product obtained from a preset proportional coefficient and the real-time power value, so as to determine the corresponding step size ; A duty cycle adjustment step for determining the real-time voltage of the current moment of the photovoltaic module is within a preset voltage range including the voltage value corresponding to the maximum power point; if the real-time voltage of the current photovoltaic module is within the preset voltage range, then according to the positive or negative situation of the voltage change amount and the corresponding step size adjust the duty cycle; if the real-time voltage of the current photovoltaic module is not within the preset voltage range, then according to the positive or negative situation of the power change amount , the voltage change amount , and the current change amount and the corresponding step size adjust the duty cycle.

9. A storage medium, characterized in that: The storage medium is a non-volatile storage medium or a non-transitory storage medium, on which a computer program is stored, and when the computer program is run by a processor, it executes the photovoltaic MPPT dual-mode perturbation control method according to any one of claims 1-7.

10. A terminal, characterized in that: Including a memory and a processor, a computer program capable of running on the processor is stored on the memory, and when the processor operates the computer program, it executes the photovoltaic MPPT dual-mode perturbation control method according to any one of claims 1-7.

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