1. A system (100) with power control strategy for a grid-connected photovoltaic system, comprising: a. a photovoltaic array; b. a plurality of power electronic converters; c. MPPT controllers; and d. a grid interface, wherein the control strategy enables stable power extraction under partial shading conditions.

2. The system as claimed in claim 1, wherein the photovoltaic array includes a plurality of series-connected PV modules forming a PV string.

3. The system as claimed in claim 1, wherein the system identifies a critical irradiance threshold beyond which shading heaviness has negligible impact on output power.

4. The system as claimed in claim 1, wherein the MPPT controller employs a Perturb and Observe algorithm adapted for partial shading conditions.

5. The system as claimed in claim 1, wherein the system operates effectively under both uniform irradiance and partial shading scenarios.

6. A method (200) for controlling power in a grid-connected photovoltaic system subject to partial shading, the method comprising: a. configuring (201) a photovoltaic array comprising a plurality of photovoltaic modules connected in series to form at least one photovoltaic string; b. measuring (202) electrical parameters including voltage and current of the photovoltaic string under operating conditions; c. analyzing (203) power–voltage characteristics of the photovoltaic string to detect the presence of partial shading; d. identifying (204) a critical irradiance threshold corresponding to shaded photovoltaic modules, beyond which variations in shading heaviness produce negligible change in output power; e. operating (205) a maximum power point tracking controller using a perturb and observe technique; f. adapting (206) a perturbation step size of the perturb and observe technique when the operating point lies within a shading-insensitive region defined by the critical irradiance threshold; g. stabilizing (207) the operating point of the photovoltaic system to reduce power oscillations and prevent convergence to local maximum power points; and h. injecting (208) extracted power into an electrical grid through a grid tied inverter.

7. The method as claimed in claim 6, wherein the identifying of the critical irradiance threshold is performed in real time based on monitored variations in output power.

8. The method as claimed in claim 6, wherein the method further comprises regulating a DC-link voltage using a power electronic converter prior to grid injection.

9. The method as claimed in claim 6, wherein the method further comprises temporarily compensating power mismatch using an energy storage device connected to the photovoltaic system.

10. The method as claimed in claim 6, wherein the method is implemented in a residential, commercial, or utility-scale grid-connected photovoltaic installation.

Description:FIELD OF THE INVENTION
The present invention relates to the field of renewable energy systems, and more particularly to grid-connected photovoltaic (PV) power generation systems. The invention specifically addresses power control and maximum power point tracking (MPPT) strategies for PV arrays operating under uniform irradiance and partial shading conditions.
BACKGROUND OF THE INVENTION
Photovoltaic (PV) systems have emerged as a reliable, clean, and sustainable source of electrical energy. PV systems are characterized by advantages such as absence of chemical emissions, recyclability, low maintenance requirements, and suitability for distributed generation. However, the output power and efficiency of PV systems are highly dependent on environmental and operational parameters including solar irradiance, module temperature, and array configuration. One of the most critical challenges affecting PV system performance is partial shading. Partial shading may occur due to clouds, nearby buildings, trees, dust accumulation, or other obstructions. Under such conditions, PV arrays exhibit multiple local maxima in their power–voltage (P–V) characteristics, leading to power losses, mismatch effects, and potential instability in conventional MPPT algorithms. Conventional MPPT techniques, such as Perturb and Observe (P&O) and Incremental Conductance, are effective under uniform irradiance but often fail to track the global maximum power point (GMPP) under partial shading conditions. Furthermore, the influence of shading heaviness and the number of shaded modules on PV string behavior has not been adequately exploited for robust control.
Accordingly, there exists a need for a robust power control strategy capable of maintaining reliable operation and enhanced power extraction from grid-connected PV systems under both uniform and partial shading conditions.
In one of the prior art, application numbered US20150188415A1 titled “Photovoltaic systems with maximum power point tracking controller” discloses a system and a method provide a photovoltaic system which regenerates the output characteristics of the photovoltaic at different ambient condition with high precision under all environmental conditions. The photovoltaic system includes a photovoltaic array, a buck/boost converter, a DC link capacitor to connect the buck/booster converter to a load/inverter, an adaptive network-based fuzzy inference maximum power point tracking controller, a voltage control loop, a proportional integral controller to maintain the output voltage of the photovoltaic array to the reference voltage by adjusting the duty ratio of buck/boost converter. In another prior-art application numbered CN105137808A titled “Maximum power point tracking method in partial shadow based on photovoltaic grid-connected power generation system” discloses a method for tracking the maximum power point under partial shading based on a photovoltaic grid-connected power generation system, including the first step, judging whether shadow shading occurs according to the operating voltage and current of the photovoltaic array; the second step, when partial shading occurs, then Move the operating point of the photovoltaic array from point B to point C; the third step is to use the maximum power point tracking method to accurately find the maximum power point. The invention establishes a digital-physical hybrid real-time simulation system for photovoltaic grid-connected power generation, which can accurately track the global maximum power point under partial shadows without additional circuits, and is applicable to various extreme lighting conditions, and the accuracy and reliability of the results are obtained. improved. In another prior-art application numbered US9800053B2 titled “Solar panels with integrated cell-level MPPT devices” provides a solar cell panel that includes a front side cover, a back-side cover, a number of solar cells situated between the front side cover and the back-side cover, and a number of maximum power point tracking (MPPT) devices situated between the front-side cover and the back-side cover. In another prior art titled “A review on MPPT techniques of PV system under partial shading condition” authored by Alivarani Mohapatra et al., discloses a concise and an organized review of various maximum power point tracking (MPPT) algorithms implemented in the photovoltaic (PV) generation system useable under partial shading condition. Various algorithms, PV modeling techniques, PV array configurations and controller topologies have been widely explored till date. But, every technique always has its advantages as well as disadvantages simultaneously; as a result, a proper literature review is essential while designing a PV generation system (PGS) under partial shading condition. In this prior art, the detailed review of MPPT algorithms has been done. The review on MPPT techniques has been classified into mainly four essential groups. The first among them includes all the new MPPT optimization algorithms, the second group includes the hybrid MPPT algorithms, the third category includes new modeling approach, and the fourth category includes the various converter topologies. The prior art provides an accessible reference to undertake mass research works in PV systems in the near future under partial shading condition. In another prior art titled “A Novel Technique Based on Peafowl Optimization Algorithm for Maximum Power Point Tracking of PV Systems Under Partial Shading Condition” authored by Dongrui Li, aims to propose a novel and powerful bio-inspired meta-heuristic optimization algorithm called peafowl optimization algorithm (POA), which is inspired by the group food searching behaviors of peafowl swarm. It can effectively achieve a suitable balance between local exploitation and global exploration thanks to its efficient exploratory and exploitative searching operators. Thus, a satisfactory MPPT performance for PV systems under partial shading condition (PSC) can be obtained based on POA. Moreover, two case studies, e.g., start-up test and step change in solar irradiation with constant temperature, are adopted to fairly and comprehensively validate the superiority and effectiveness of POA in contrast with particle swarm optimization (PSO) and teaching-learning-based optimization (TLBO), respectively.
The present invention introduces a novel approach by integrating capacitive sensors and thermal sensors into a unified occupancy detection system, thereby overcoming the demerits of the existing prior arts.
OBJECTIVES OF THE INVENTION
1. The primary objective of the present invention is to analyze the effect of shading heaviness and the number of shaded modules on the P–V characteristics of PV strings.
2. It is an objective of the present invention to identify a critical irradiance threshold beyond which the PV string becomes insensitive to shading heaviness.
3. It is an objective of the present invention to develop a control strategy that ensures stable and efficient power extraction under both uniform and partial irradiance conditions.
4. It is an objective of the present invention to experimentally validate the proposed strategy using a grid-connected PV system with MPPT control.
5. It is an objective of the present invention to improve overall system efficiency and reliability without significant increase in system complexity or cost.
SUMMARY OF THE INVENTION
This summary is provided to introduce a selection of concepts, in a simplified format, that are further described in the detailed description of the invention.
This summary is neither intended to identify key or essential inventive concepts of the invention and nor is it intended for determining the scope of the invention.
The present invention proposes a robust power control strategy for a grid-connected photovoltaic system operating under partial shading conditions. A PV string comprising multiple solar modules connected in series is analyzed to study the impact of partial shading on its power–voltage characteristics. The present invention identifies a critical irradiance threshold for shaded modules, beyond which variations in shading heaviness have negligible impact on the output power of the PV string. Based on this observation, the characteristics of the PV array under uniform illumination and partial shading are modified to enhance resistance to shading effects. A grid-connected PV system is implemented comprising PV panels, battery management devices, power electronic converters, and MPPT controllers. The system employs a Perturb and Observe (P&O) MPPT algorithm adapted to operate effectively under both homogeneous sunlight and partial shading conditions. Experimental validation using a developed hardware prototype demonstrates improved power tracking, stability, and robustness of the proposed control strategy under varying operating conditions. It is an aspect of the invention to develop a system (100) with power control strategy for a grid-connected photovoltaic system, having a photovoltaic array, a plurality of power electronic converters, MPPT controllers and a grid interface, in which the control strategy enables stable power extraction under partial shading conditions. It is an aspect of the invention to develop a system (100) with power control strategy for a grid-connected photovoltaic system where the photovoltaic array includes a plurality of series-connected PV modules forming a PV string. It is an aspect of the invention to develop a system (100) with power control strategy for a grid-connected photovoltaic system, where the system identifies a critical irradiance threshold beyond which shading heaviness has negligible impact on output power. It is an aspect of the invention to develop a system (100) with power control strategy for a grid-connected photovoltaic system, where the MPPT controller employs a Perturb and Observe algorithm adapted for partial shading conditions. It is an aspect of the invention to develop a system (100) with power control strategy for a grid-connected photovoltaic system, where the system operates effectively under both uniform irradiance and partial shading scenarios. It is an aspect of the invention to obtain a method (100) with power control strategy for a grid-connected photovoltaic system, where, the method have the following steps: configuring (201) a photovoltaic array comprising a plurality of photovoltaic modules connected in series to form at least one photovoltaic string, measuring (202) electrical parameters including voltage and current of the photovoltaic string under operating conditions, analyzing (203) power–voltage characteristics of the photovoltaic string to detect the presence of partial shading, identifying (204) a critical irradiance threshold corresponding to shaded photovoltaic modules, beyond which variations in shading heaviness produce negligible change in output power, operating (205) a maximum power point tracking controller using a perturb and observe technique, adapting (206) a perturbation step size of the perturb and observe technique when the operating point lies within a shading-insensitive region defined by the critical irradiance threshold, stabilizing (207) the operating point of the photovoltaic system to reduce power oscillations and prevent convergence to local maximum power points and injecting (208) extracted power into an electrical grid through a grid-tied inverter. It is yet another aspect of the invention to obtain a method (200), where the identifying of the critical irradiance threshold is performed in real time based on monitored variations in output power. It is yet another aspect of the invention to obtain a method (200), where the method further comprises regulating a DC-link voltage using a power electronic converter prior to grid injection. It is yet another aspect of the invention to obtain a method (200), where the method further comprises temporarily compensating power mismatch using an energy storage device connected to the photovoltaic system. It is yet another aspect of the invention to obtain a method (200), where the method is implemented in a residential, commercial, or utility-scale grid-connected photovoltaic installation.
To further clarify advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The illustrated embodiments of the subject matter will be understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and methods that are consistent with the subject matter as claimed herein, wherein:
Figure 1 Illustrates the proposed grid connected PV system.
Figure 2 Illustrates the flowchart of Perturb & Observe MPPT.
Figure 3 Illustrates the P&O MPPT under partial shading condition.
Figure 4 Illustrates the line diagram of the proposed system.
Figure 5 Illustrates the monitoring maximum power (a) P&O (b) partial shading of P&O.
Figure 6 Illustrates the power management for a 900-watt load using the P&O MPPT algorithm (a) PV system (b) grid (c) battery.
The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION OF THE INVENTION
The detailed description of various exemplary embodiments of the disclosure is described herein with reference to the accompanying drawings. It should be noted that the embodiments are described herein in such details as to clearly communicate the disclosure. However, the amount of details provided herein is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosure as defined by the appended claims.
It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a",” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.
It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may, in fact, be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
In addition, the descriptions of "first", "second", “third”, and the like in the present invention are used for the purpose of description only, and are not to be construed as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first" and "second" may include at least one of the features, either explicitly or implicitly.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
PV String Modeling and Shading Analysis In accordance with the invention, a photovoltaic string is formed by connecting multiple PV modules in series. Under uniform irradiance, the PV string exhibits a single maximum power point. Under partial shading, bypass diodes become active, resulting in multiple peaks in the P–V curve. The invention investigates the influence of both the number of shaded modules and shading heaviness on the PV string performance. It has been observed that as the irradiance of shaded modules approaches a critical threshold, the output power of the PV string becomes less sensitive to further reductions in irradiance. Uniform and Partial Shading Scenarios Two operating scenarios are considered: A uniform irradiance condition with no partial shading. A partial shading condition with varying irradiance levels on different modules. The electrical characteristics of the PV array are modified in both scenarios to improve robustness and power extraction capability. Grid-Connected System Configuration The grid-connected PV system comprises: A photovoltaic array consisting of multiple PV panels. DC–DC power converters for voltage regulation. MPPT controllers implementing the P&O algorithm. Battery management devices for energy storage and regulation. A grid-tied inverter for synchronization and power injection into the utility grid. MPPT Control Strategy The Perturb and Observe MPPT algorithm is employed due to its simplicity and ease of implementation. The algorithm is adapted to track the operating point effectively under both uniform and partial shading conditions, ensuring convergence to a stable operating region close to the global maximum power point. Experimental Validation
A hardware prototype of the proposed grid-connected PV system is developed. Various operating conditions, including homogeneous sunlight and partial shading, are tested. Experimental results confirm that the proposed strategy enhances system stability, reduces power oscillations, and improves overall energy extraction.
GRID CONNECTED PV SYSTEM
To generate maximum power, an MPPT controller was used in the proposed system. The power generated from the grid-connected PV system is dependent on three major stages: the PV panel configuration, DC/DC converter, and DC/AC inverter. A soft computing technique is applied to each stage to improve the generated power. The PV output depends purely on the weather conditions and cell temperature. A PV array typically uses the maximum power point tracking (MPPT) technique to continuously deliver the highest power to the load with respect to variations in irradiation and temperature. A converter circuit was necessary to match the terminal voltage of the solar panel in the proposed system, and a boost converter controls the possible peak power by changing the converter duty cycle. Fig.1 shows the proposed system of PV interfaced with grid.
OPTIMIZATION ALGORITHMS
Optimization is a problem in many scientific and technological fields. Such challenges can often be very complex due to the realistic and practical character of the target function or model constraints. A common optimization problem involves minimizing or maximizing an objective function that is subject to complex, nonlinear characteristics with considerable equality and/or equality requirements. Optimization techniques are an excellent option for resolving the controller design due to its complexity. Optimization algorithms are a well-established field of research in electronic design that holds promise for producing the optimum results for complex systems. In this investigation, the MPPT algorithm (perturb and observe) described the highest power tracking from the solar panels.
The Perturb and Observe Algorithm
Fig.2 displays the P&O MPPT flowchart. The PV system monitored the panel's continuous maximum temperature and the irradiance representation of the P&O flow graphics to boost output power. The reference voltage and current values were set to a specific value after the voltage and current of the solar panel were measured in Step 1, PV Voltage and Current. The measured voltage and current were multiplied to determine the solar panel's power in Step 2 of the PV system's power calculation. The values provided for power and voltage that differ from the usual value in Step 3 are estimations. Using a two-phase reference signal based on the unique power value is step 4. If the voltage discrimination and power discrimination levels are both less than zero, the MOSFET/IGBT gate pulse will be subjected to the duty period differences and addition.
P&O MPPT Partial Shading Algorithm
To achieve high-quality performance, Fig. 3 illustrates the perturb and observe MPPT under partial shading conditions. An MPPT is used to test the converter at different intervals during a global peak seeking stage in order to determine the operating condition that is closest to the peak power and locate a peak power point that is near the actual peak power point. The algorithm is then used to determine the peak power. On the other hand, the P&O method produced fine tracking. However, PVs exhibit significant power differences (dP) when solar radiation varies. Consequently, if the condition is detected, the computer looks for a peak power point. On the other hand, the peak MPPT stage looks for a worldwide maximum in two to five minutes. To attain superior performance, Fig. 3 shows how to observe and perturb MPPT while there is partial shading. In order to identify the mode of operation that is closest to the peak power and find a peak power point that is close to the actual peak power point, an MPPT is utilized to test the converter at various intervals during a global peak seeking stage. The peak power is then calculated using the algorithm. The P&O approach, however, resulted in fine tracking. However, PVs display considerable power changes (dP) when solar radiation fluctuates [23]. Consequently, if the condition is identified, the computer hunts for a peak power point. The peak MPPT stage, on the other hand, seeks a global maximum in two to five minutes.
Hardware Results
The PV array's line diagram connects to the battery via a three-phase VSC and the grid via a direct current boost converter, as seen in Fig. 4. A battery with a buck boost bidirectional converter, a boost converter, an autotransformer acting as the utility grid, a 3-phase vcs with a 10 kVA capability, and a 3-phase pv array with a 1 kW capacity at uniform irradiance are all included in the system components model. The buck-boost converter's features are listed in Table 3. The battery and vsc specifications are shown in Tables 4 and 5, respectively.
Parameter Variables Value
Pout 2000W
Vin 150V
Vout 350V
fₛ(max) 100KHz
L 5mH
C3, C4 1500µF
IGBT Rating 1200V/100A
TABLE 3
This study tests the hardware model under different conditions. a. Using partial shade and perturb and observe techniques, grid-connected solar systems' power is tracked. b. Under various loads, P&O and partial shading power management techniques employ perturb and observe algorithms. c. Using current control to reduce harmonics in the grid's current connection.
Parameter Variables Value
Pout 10KVA
V_DC (link) 350V
C_DC (link) 660µF/450Vdc
fs(max) 100KHz
TABLE 4

Parameter Variables Value
V_batt 12V
Ah 26Ah
N_batt 12
Battery Type MF-VRLA
TABLE 5
Solar PV maximum power tracking using partial shade and the P&O approach in a grid-connected system
Figure 5 (a) shows the maximum power tracking of the solar PV system using the perturb and observe algorithm under various load situations and irradiance conditions ranging from 1000W/m2 to 600W/m2 at 25°C. The numbers 1, 2, 3, and 4 represent, respectively, no load without controller, 250W without controller, 250W with controller, and 500W with controller 4 and 7. A 1000W load in the given MPPT circumstances 5 and 8. MPPT recommended parameters for a 750W load 6 and 10. Furthermore, a condition of 9 is displayed with a load of 1250W and a controller, as shown in Fig. 5 (a). In the P&O MPPT scenario, the solar PV system's maximum tracking power was 850W. Figure 5 (b) illustrates power tracking of solar PV systems using partial shadow and the perturb and observe algorithm at different irradiances from 1000 W/m2 to 600 W/m2 at 25 °C under various load scenarios. The numbers 1 and 2 represent no load at all, whereas the numbers 3 and 4 represent loads with a controller of 250 W and 500 W, respectively. 4 and 7. An MPPT controller with a 750 W load demonstrated a 1000 W load under the designated MPPT conditions 6 and 10, as well as conditions 5 and 8. Additionally, as Fig. 5 (b) illustrates, a load of 1250 W with a controller indicates a condition of 9. The highest power tracking of the solar PV system with partial shadowing was 770W in the P&O MPPT scenario.
Modifying and verifying algorithms for Perturb and Observe and partial shading power management under various loads
Here, power management between the battery, grid, and PV system is accomplished through the use of the perturb and observe approach and the perturb and observe MPPT algorithm. Figs. 6 (a), (b), and (c) illustrate the perturb and observe MPPT algorithm power management technique for a 900 W load demand. 550 W from the PV system, 40 W from the battery, and 40 W from the grid were used to meet the 900 W total load requirement.
P_load
(W) MPPT Method P_PV (W) P_grid (W) P_batt (W)
1200 P&O 700 460 40
900 P&O 550 310 40
500 P&O 400 100 0
1200 Partial shading with P&O 600 560 40
900 Partial shading with P&O 440 420 40
500 Partial shading with P&O 330 171 0
TABLE 7
In one preferred embodiment, the invention provides a PV string comprising a plurality of series-connected photovoltaic modules, each equipped with bypass diodes. The control system continuously monitors string voltage and power variation to identify an irradiance threshold at which further reduction in shaded module irradiance produces negligible change in output power. Once this threshold is detected, the controller stabilizes the operating point to avoid unnecessary perturbations.
In another embodiment, the invention integrates a modified Perturb and Observe MPPT controller with a grid-connected inverter. Under partial shading conditions, the controller limits perturbation step size when the operating point lies within the
identified shading-insensitive region, thereby preventing oscillation around local maxima and ensuring stable power injection to the grid. Several prior-art solutions employ complex global MPPT techniques such as particle swarm optimization, genetic algorithms, or artificial intelligence-based controllers. While effective in locating the global maximum power point, these methods require high computational resources, complex tuning, and increased system cost. The present invention differs from the above prior-art techniques by identifying a shading-insensitive operating region based on a critical irradiance threshold. This allows the use of a simple P&O MPPT controller while achieving robustness comparable to advanced global MPPT methods, without added computational complexity. Partial shadowing poses a major threat to photovoltaic systems. The power, voltage, and current under uniform illumination and partial shading conditions were investigated in order to comprehend the effects of part shading and bypass diodes on the PV panel. Partial shadowing can drastically lower a solar system's maximum power. Based on the selective shading patterns, lighting intensity, and arrangement used to establish a connection with each solar module, a system's vulnerability to partial shading may change. For a grid-connected PV system using P&O MPPT under partial shading and uniform irradiation under various load situations, this paper suggests a maximum power tracking and power management technique. THD enhancement, power management strategy, and maximum power were among the areas in which the proposed system with P&O and partial shade employing MPPT techniques was validated. Additionally, the maximum power of 850W extracted by P&O MPPT and the maximum power of 770W extracted by partial shading with P&O MPPT in hardware implementation have been demonstrated.
Advantages of the Invention
The present invention offers several advantages, including:
• Robust operation under partial shading conditions.
• Improved power extraction and system efficiency.
• Reduced sensitivity to shading heaviness beyond a critical threshold.
• Compatibility with conventional MPPT techniques.
• Simple implementation suitable for practical grid-connected PV systems.
Industrial Applicability
The invention is industrially applicable to residential, commercial, and utility-scale grid-connected photovoltaic installations. It is particularly suitable for PV systems installed in urban environments where partial shading is unavoidable.
, Claims:1. A system (100) with power control strategy for a grid-connected photovoltaic system, comprising:
a. a photovoltaic array;
b. a plurality of power electronic converters;
c. MPPT controllers; and
d. a grid interface, wherein the control strategy enables stable power extraction under partial shading conditions.
2. The system as claimed in claim 1, wherein the photovoltaic array includes a plurality of series-connected PV modules forming a PV string.
3. The system as claimed in claim 1, wherein the system identifies a critical irradiance threshold beyond which shading heaviness has negligible impact on output power.
4. The system as claimed in claim 1, wherein the MPPT controller employs a Perturb and Observe algorithm adapted for partial shading conditions.
5. The system as claimed in claim 1, wherein the system operates effectively under both uniform irradiance and partial shading scenarios.
6. A method (200) for controlling power in a grid-connected photovoltaic system subject to partial shading, the method comprising:
a. configuring (201) a photovoltaic array comprising a plurality of photovoltaic modules connected in series to form at least one photovoltaic string;
b. measuring (202) electrical parameters including voltage and current of the photovoltaic string under operating conditions;
c. analyzing (203) power–voltage characteristics of the photovoltaic string to detect the presence of partial shading;
d. identifying (204) a critical irradiance threshold corresponding to shaded photovoltaic modules, beyond which variations in shading heaviness produce negligible change in output power;
e. operating (205) a maximum power point tracking controller using a perturb and observe technique;
f. adapting (206) a perturbation step size of the perturb and observe technique when the operating point lies within a shading-insensitive region defined by the critical irradiance threshold;
g. stabilizing (207) the operating point of the photovoltaic system to reduce power oscillations and prevent convergence to local maximum power points; and
h. injecting (208) extracted power into an electrical grid through a grid tied inverter.
7. The method as claimed in claim 6, wherein the identifying of the critical irradiance threshold is performed in real time based on monitored variations in output power.
8. The method as claimed in claim 6, wherein the method further comprises regulating a DC-link voltage using a power electronic converter prior to grid injection.
9. The method as claimed in claim 6, wherein the method further comprises temporarily compensating power mismatch using an energy storage device connected to the photovoltaic system.
10. The method as claimed in claim 6, wherein the method is implemented in a residential, commercial, or utility-scale grid-connected photovoltaic installation.