Maximum power point tracking method and system

Abstract

The embodiment of the invention discloses a maximum power point tracking method and system, and the method comprises the steps: collecting the electrical information of a photovoltaic array, comparing the electrical information with a preset stability threshold value, and maintaining a current MPPT strategy if the electrical information is in a normal range; if the electrical information deviates from the normal range, the disturbance step length is adjusted, and an MPPT strategy is updated according to the adjusted disturbance step length; wherein the MPPT strategy specifically comprises the following steps: processing the disturbance step length, specifically, multiplying the disturbance step length by a coefficient which is inversely proportional to the power change sensitivity; and disturbing the duty ratio according to the processed disturbance step length. According to the method, the maximum power point of the fluctuating photovoltaic array can be quickly and accurately tracked.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of photovoltaic power generation technology, and in particular to a maximum power point tracking method and system. Background Art

[0002] In current photovoltaic power generation systems, maximum power point tracking (MPPT) technology is the key to improving energy collection efficiency. However, existing MPPT technology has problems such as slow tracking speed, low accuracy, high energy consumption, and insufficient system stability. It is often unable to quickly and accurately track the maximum power point, resulting in low photovoltaic power generation efficiency.

[0003] In order to make full use of photovoltaic cells to maximize their output power, it is necessary to track their maximum power point to ensure that the photovoltaic cells always work at the maximum power point. At present, some research has been conducted on the maximum power point tracking algorithm at home and abroad, such as the perturbation observation method, the conductance increment method, and the hill climbing (HC) algorithm. However, as the power approaches the maximum power point, the sensitivity of these algorithms to fluctuations caused by factors such as light changes will decrease, and they cannot adapt well to photovoltaic power generation systems. Summary of the invention

[0004] The embodiments of the present application provide a maximum power point tracking method and system to improve the maximum power point tracking efficiency of photovoltaic power generation.

[0005] In a first aspect, an embodiment of the present application provides a maximum power point tracking method, which is applied to a photovoltaic array, and the method includes: Collecting electrical information of the photovoltaic array and comparing it with a preset stability threshold, and maintaining the current MPPT strategy if the electrical information is within a normal range; If the electrical information deviates from the normal range, the disturbance step size is adjusted, and the MPPT strategy is updated according to the adjusted disturbance step size; The MPPT strategy specifically includes: Processing the disturbance step length, specifically, multiplying the disturbance step length by a coefficient inversely proportional to the power change sensitivity; The duty cycle is disturbed according to the disturbance step size after the processing.

[0006] In some possible implementations, the perturbation step size is as follows: ; in, D is the perturbation step size, K is a constant, P is the output power of the photovoltaic array, and D is the duty cycle.

[0007] In some possible implementations, collecting electrical information of the photovoltaic array and comparing it with a set stability threshold specifically includes: Collecting electrical information of the photovoltaic array at intervals of a preset duration, wherein the electrical information includes output voltage and output current; Instantaneous power and efficiency are calculated based on the electrical information and compared with preset stability thresholds.

[0008] In some possible implementations, the method further includes: collecting environmental parameters of the photovoltaic array at preset time intervals; The maximum power point of the photovoltaic array is adjusted according to the environmental parameters.

[0009] In some possible implementations, the method further includes: Determining whether the electrical information and environmental parameters reach a safety threshold; If so, the circuit protection device is activated.

[0010] In a second aspect, an embodiment of the present application provides a maximum power point tracking system, which is applied to a photovoltaic array, and the system includes: A first detection unit, used for collecting electrical information of the photovoltaic array and comparing it with a preset stability threshold, and maintaining the current MPPT strategy if the electrical information is within a normal range; A first processing unit, configured to adjust a disturbance step size when the electrical information deviates from a normal range, and update an MPPT strategy according to the adjusted disturbance step size; The MPPT strategy specifically includes processing the disturbance step length, specifically multiplying the disturbance step length by a coefficient inversely proportional to the power change sensitivity; The duty cycle is disturbed according to the disturbance step size after the processing.

[0011] In some possible implementations, the perturbation step size is as follows: ; in, D is the disturbance step size, P is the output power of the photovoltaic array, and D is the duty cycle.

[0012] In some possible implementations, the first detection unit is further used to collect electrical information of the photovoltaic array at intervals of a preset duration, wherein the electrical information includes output voltage, current, and ambient temperature data; The first detection unit is further used to calculate instantaneous power and efficiency according to the electrical information, and compare them with a preset stability threshold.

[0013] In some possible implementations, the system includes: A second detection unit, used for collecting environmental parameters of the photovoltaic array at intervals of a preset time length; The second processing unit is used to adjust the maximum power point of the photovoltaic array according to the environmental parameters.

[0014] In some possible embodiments, the system includes; The protection unit is used to start the circuit protection device when the electrical information and environmental parameters reach a safety threshold.

[0015] The beneficial effects of this application are: The embodiment of the present application collects electrical information of the photovoltaic array and compares it with a preset stability threshold. If the electrical information is within a normal range, the current MPPT strategy is maintained. If the electrical information deviates from the normal range, the disturbance step size is adjusted, and the MPPT strategy is updated based on the adjusted disturbance step size. The MPPT strategy specifically includes processing the disturbance step size, that is, multiplying the disturbance step size by a coefficient inversely proportional to the sensitivity of power changes, and then perturbing the duty cycle based on the processed disturbance step size, thereby achieving the technical effect of quickly and accurately tracking the maximum power point of a fluctuating photovoltaic array. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 is a flow chart of a maximum power point tracking method provided in an embodiment of the present application; Figure 2 is a schematic diagram of a maximum power point tracking system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described in detail by way of implementation methods with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, but not all of the embodiments. In the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0019] It should be noted that: in the accompanying drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions; in the description of the present application, the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; in the description of the present application, "first", "second", etc. are only used to distinguish each other, rather than to indicate their importance and order, etc.

[0020] In the description of this application, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a movable connection, or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal communication of two components, etc. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0021] The present invention provides a maximum power point tracking method for a photovoltaic array. The method includes the following steps: Step 110: Collect electrical information of the photovoltaic array and compare it with a preset stability threshold. If the electrical information is within a normal range, maintain the current MPPT strategy.

[0022] Step 120: If the electrical information deviates from the normal range, the disturbance step size is adjusted, and the MPPT strategy is updated according to the adjusted disturbance step size.

[0023] Among them, the MPPT strategy specifically includes: Step 130: Process the disturbance step length, specifically, multiply the disturbance step length by a coefficient inversely proportional to the power variation sensitivity.

[0024] Step 140: Disturb the duty cycle according to the processed disturbance step length.

[0025] The data can be collected and compared by real-time monitoring of the output characteristics of the photovoltaic array, using machine learning technology to analyze the data, and dynamically adjusting the duty cycle of the MPPT algorithm, thereby achieving maximum power point tracking. The embodiment of the present invention is illustrated by the following method: The voltage, current, temperature, light intensity and other environmental parameters of the photovoltaic array are monitored in real time through high-precision sensors; the collected data is preprocessed to extract key features, such as the PV curve characteristics of the photovoltaic array, for subsequent machine learning model training; supervised learning algorithms, such as support vector machines (SVM) or artificial neural networks (ANN), are used to train historical data and establish a prediction model for the maximum power point; the trained model is used to predict the maximum power point in real time according to the current environmental parameters, and the duty cycle of the DC / DC converter is adjusted through the control circuit to track the maximum power point. It is worth noting that this implementation is only used as an example.

[0026] In the perturbation observation method, in the process of adjusting the duty cycle by perturbation so that the output power of the photovoltaic array gradually approaches the maximum power point (MPP), the output characteristic of the system does not change linearly, that is, before the distance from the MPP is far away, the power increases with the increase of voltage, and when approaching the MPP, the power decreases with the increase of voltage. Therefore, the sensitivity of power change decreases because the dependence of current on voltage changes near the MPP, making the slope of the power curve smaller. Therefore, it is necessary to multiply the perturbation step by a coefficient related to power sensitivity, while ensuring the tracking efficiency of the maximum power point, and quickly respond to external environmental factors such as changes in light, so as to adapt to the constantly fluctuating photovoltaic array power generation system.

[0027] In a possible implementation, the relationship between the disturbance step size and the output characteristics of the photovoltaic array is as follows: ; in, D is the perturbation step size, K is a constant, P is the output power of the photovoltaic array, and D is the duty cycle. It represents the derivative of power to duty cycle, reflecting the sensitivity of power change. When approaching the maximum power point, decreases, resulting in a perturbation step size Increase, that is, when approaching MPP, due to the reduced sensitivity of power changes, small disturbances may not cause significant changes in power, which will reduce the efficiency of the MPPT algorithm. Increasing the disturbance step size can improve the efficiency of the algorithm, reduce unnecessary calculations and adjustments, and reduce switching frequency and power consumption.

[0028] In some possible implementations, step 110 specifically includes the following steps: Step 111: Collecting electrical information of the photovoltaic array at preset intervals, wherein the electrical information includes output voltage and output current; Step 112: Calculate instantaneous power and efficiency based on the electrical information, and compare with a preset stability threshold.

[0029] Specifically, the instantaneous power and efficiency of the photovoltaic array can be calculated by the following formula:

[0030]

[0031] Where S is the area of ​​the photovoltaic array. The stability of photovoltaic array power generation is evaluated by comparing the real-time power and efficiency with historical data.

[0032] In some possible implementations, the method further comprises the following steps: Step 150: Collect environmental parameters of the photovoltaic array at preset time intervals.

[0033] Step 160: Adjust the maximum power point of the photovoltaic array according to the environmental parameters.

[0034] When a change in system status is detected, such as power fluctuation or efficiency drop, the monitoring module will trigger the following adaptive adjustment process: Adjust the perturbation step size, dynamically adjust the perturbation step size in the perturbation-observation algorithm according to changes in system status. For example, when a power drop is detected, increase it to speed up the search for the maximum power point.

[0035] Optimize the operating point by fine-tuning the maximum power point (MPP) of the PV array to adapt to environmental changes such as fluctuations in temperature and light intensity.

[0036] In some possible implementations, the method further comprises the following steps: Step 170: Determine whether the electrical information and environmental parameters have reached a safety threshold.

[0037] Step 180: If yes, then start the circuit protection device.

[0038] Starting the circuit protection device may include one or more implementations described below: Overvoltage protection: In a photovoltaic system, excessive voltage may damage power electronic devices. Therefore, an overvoltage protection circuit is set in the controller. This circuit uses a comparator to monitor the output voltage of the photovoltaic array and compare it with the set safety threshold. When the voltage exceeds the threshold, the comparator output signal triggers a relay or MOSFET switch to cut off the connection between the photovoltaic array and the load, thereby protecting the system.

[0039] Overcurrent protection: The overcurrent protection circuit monitors the current flowing through the photovoltaic array. By connecting a current sensor in series, the current signal is converted into a voltage signal and then input into the comparator. If the current exceeds the preset limit, the comparator output signal will activate the protection circuit, cut off the current path, and prevent overcurrent from damaging system components.

[0040] Abnormal temperature protection: The temperature sensor monitors the internal temperature of the controller in real time. Once the temperature exceeds the safe range, the sensor output signal will activate the protection mechanism. This may include reducing the operating frequency, triggering fan cooling, or directly cutting off the power supply to prevent the controller from being damaged due to overheating.

[0041] Short circuit protection: Short circuit protection is achieved by real-time monitoring of changes in output current and voltage. When a sudden increase in current and a sharp drop in voltage are detected, it indicates that a short circuit may have occurred. At this time, the protection circuit immediately operates to cut off the power supply.

[0042] The present application also provides a maximum power point tracking system, which is applied to a photovoltaic array. The system includes: A first detection unit 210 is used to collect electrical information of the photovoltaic array and compare it with a preset stability threshold, and if the electrical information is within a normal range, maintain the current MPPT strategy; A first processing unit 220, configured to adjust a disturbance step size when the electrical information deviates from a normal range, and update an MPPT strategy according to the adjusted disturbance step size; The MPPT strategy specifically includes processing the disturbance step length, specifically multiplying the disturbance step length by a coefficient inversely proportional to the power change sensitivity; The duty cycle is disturbed according to the disturbance step size after the processing.

[0043] In some possible implementations, the perturbation step size is as follows: ; in, D is the disturbance step size, P is the output power of the photovoltaic array, and D is the duty cycle.

[0044] In some possible implementations, the first detection unit 210 is further configured to collect electrical information of the photovoltaic array at intervals of a preset duration, wherein the electrical information includes output voltage, current, and ambient temperature data; The first detection unit 210 is further configured to calculate instantaneous power and efficiency according to the electrical information, and compare the instantaneous power and efficiency with a preset stability threshold.

[0045] In some possible implementations, the system includes: A second detection unit 230 is used to collect environmental parameters of the photovoltaic array at intervals of a preset time length; The second processing unit 240 is configured to adjust the maximum power point of the photovoltaic array according to the environmental parameters.

[0046] In some possible embodiments, the system includes; The protection unit 250 is used to start the circuit protection device when the electrical information and environmental parameters reach a safety threshold.

[0047] An embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program code. When the computer program code is executed on a computer, the computer executes a method of any possible implementation method in the above embodiments.

[0048] An embodiment of the present application further provides a computer program product, which includes: a computer program code, which, when executed on a computer, enables the computer to execute a method as any possible implementation method of the first aspect or the second aspect.

[0049] The embodiment of the present application also provides a computer program. When the computer program code is executed on a computer, the computer executes a method of any possible implementation method in any of the aforementioned embodiments.

[0050] Those skilled in the art should be aware that in one or more of the above examples, the functions described in the embodiments of the present application can be implemented with hardware, software, firmware, or any combination thereof. When implemented using software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein the communication media include any media that facilitates the transmission of a computer program from one place to another. The storage medium can be any available medium that a general or special-purpose computer can access.

[0051] Note that the above are only preferred embodiments of the present application and the technical principles used. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present application. Therefore, although the present application is described in more detail through the above embodiments, the present application is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. A maximum power point tracking method, applied to a photovoltaic array, characterized in that: The method comprises: Collecting electrical information of the photovoltaic array and comparing it with a preset stability threshold, and maintaining the current MPPT strategy if the electrical information is within a normal range; If the electrical information deviates from the normal range, the disturbance step size is adjusted, and the MPPT strategy is updated according to the adjusted disturbance step size; The MPPT strategy specifically includes: Processing the disturbance step length, specifically, multiplying the disturbance step length by a coefficient inversely proportional to the power change sensitivity; The duty cycle is disturbed according to the disturbance step size after the processing.

2. The maximum power point tracking method according to claim 1, characterized in that: The perturbation step size is as follows: ； in, D is the perturbation step size, K is a constant, P is the output power of the photovoltaic array, and D is the duty cycle.

3. The maximum power point tracking method according to claim 1, characterized in that: The collecting of electrical information of the photovoltaic array and comparing it with a set stability threshold specifically includes: Collecting electrical information of the photovoltaic array at intervals of a preset duration, wherein the electrical information includes output voltage and output current; Instantaneous power and efficiency are calculated based on the electrical information and compared with preset stability thresholds.

4. The maximum power point tracking method according to claim 3, characterized in that: The method further comprises: collecting environmental parameters of the photovoltaic array at preset time intervals; The maximum power point of the photovoltaic array is adjusted according to the environmental parameters.

5. The maximum power point tracking method according to claim 4, characterized in that: The method further comprises: Determining whether the electrical information and environmental parameters reach a safety threshold; If so, the circuit protection device is activated.

6. A maximum power point tracking system, applied to a photovoltaic array, characterized in that: The system comprises: A first detection unit, used for collecting electrical information of the photovoltaic array and comparing it with a preset stability threshold, and maintaining the current MPPT strategy if the electrical information is within a normal range; A first processing unit, configured to adjust a disturbance step size when the electrical information deviates from a normal range, and update an MPPT strategy according to the adjusted disturbance step size; The MPPT strategy specifically includes processing the disturbance step length, specifically multiplying the disturbance step length by a coefficient inversely proportional to the power change sensitivity; The duty cycle is disturbed according to the disturbance step size after the processing.

7. The maximum power point tracking system according to claim 6, characterized in that: The perturbation step size is as follows: ； in, D is the disturbance step size, P is the output power of the photovoltaic array, and D is the duty cycle.

8. The maximum power point tracking system according to claim 6, characterized in that: The first detection unit is also used to collect electrical information of the photovoltaic array at each preset time interval, wherein the electrical information includes output voltage, current and ambient temperature data; The first detection unit is further used to calculate instantaneous power and efficiency according to the electrical information, and compare them with a preset stability threshold.

9. The maximum power point tracking system according to claim 8, characterized in that: The system comprises: A second detection unit, used for collecting environmental parameters of the photovoltaic array at intervals of a preset time length; The second processing unit is used to adjust the maximum power point of the photovoltaic array according to the environmental parameters.

10. The maximum power point tracking system according to claim 9, characterized in that: The system comprises: The protection unit is used to start the circuit protection device when the electrical information and environmental parameters reach a safety threshold.

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