**1. Introduction**

As our civilization advances in technology, it necessitates a greater use of energy in today's world. Renewable energy sources have the potential to cater the increasing demand for energy in various forms. In near future, demand for renewable energy will rise in all sectors, including heating, power, and transportation, etc. Solar power is more admired than other renewable energy sources due to its widespread availability and well-established technology. This is because of recent developments in increasing accuracy and tracking speed for maximum energy harvesting [1].

Direct current is generated when photons from sunlight strike the solar cells. A seriesparallel combination of these cells gives rise to a PV module, which when further combined together forms a PV array. The literature reveals that the characteristics of solar cells are

**Citation:** Sharma, A.K.; Pachauri, R.K.; Choudhury, S.; Minai, A.F.; Alotaibi, M.A.; Malik, H.; Márquez, F.P.G. Role of Metaheuristic Approaches for Implementation of Integrated MPPT-PV Systems: A Comprehensive Study. *Mathematics* **2023**, *11*, 269. https://doi.org/ 10.3390/math11020269

Academic Editors: Valeriu David and Camelia Petrescu

Received: 16 November 2022 Revised: 13 December 2022 Accepted: 20 December 2022 Published: 4 January 2023

**Copyright:** © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

non-linear [2], which degrades their conversion efficiency. Therefore, it is required to extract all the power accessible from the PV module. Moreover, a PV module does not supply power constantly on account of various factors such as temperature, irradiance, geographical conditions, and so on [3].

The P–V curve of any solar module has an optimal point, i.e., the global maximum power point (GMPP), that varies depending on temperature and solar irradiance. The PV module produces the most power at that point [4]. To confirm that the PV module is always operating at GMPP, MPPT techniques come into picture. MPPT techniques are algorithms that are implemented via software and power electronics hardware combination in any solar controller. These algorithms aid in ensuring that the output of solar array is always at its peak. MPPT techniques perform this task by continuous power tracking methodology to determine the best operating power point from solar array. Since the maximum power of a solar array varies in accordance with many environmental conditions, tracking this power is crucial for utmost utilization of solar energy. The MPPT system's aim is to sample the output of the PV array and apply the appropriate resistance to obtain maximum power for any given environmental conditions. Thus, these techniques function as an impedancematching device between the array and load with the help of varying the duty cycle of the DC-DC converter. The whole process is controlled by software and a micro-controller. MPPT-equipped controllers have numerous advantages over other controllers, such as the following:


There are several approaches to achieving MPPT, which are discussed in this article.

Many researchers have published their findings on MPPT algorithms. Refs. [5–7] compare various MPPT approaches for uniform irradiance and PSCs for solar PV systems, whereas [8,9] focus specifically on PSCs. Traditional MPPT techniques such as P&O [10], INC [11], and HC [12] are proficient for uniform irradiance with a unique peak. They are unsuitable when the PV system is subjected to PSCs. The researchers attempted to improve on traditional MPPT algorithms by combining them with advanced strategies [13–15]. Figure 1a,b show a generalized block diagram of standalone and grid-connected PV systems.

(**a**)

(**b**)

**Figure 1.** Generalized block diagram of (**a**) standalone PV system and (**b**) grid-connected PV system.

However, the choice of a specific MPPT approach is still an ambiguity. As a result, there is strong need to investigate and reassess the developed strategies on regular basis, as this will help in the selection of a specific technique based on the context. Different conventional and AI-based meta-heuristic MPPT techniques are reviewed and compared in this article based on a variety of factors such as tracking time, complexity, oscillations around GMPP, implementation cost, and so on. BI [16,17], SI [18,19], ANN, FLC, and ECI are explained and reviewed by authors on various parameters.

The novelty of this work can be summarized as an approach to presenting qualitative comparative analysis and set-theoretic research, with emphasis on tabular presentation (technical datasheet presentation) of the chief attributes of conventional and AI-based MPPT techniques.

This data positioning approach is most appropriate format for reading and understanding the data. Quantifying these data helps in comprehensive analysis and comparing different data sets, thereby bringing out the most important and widely used conventional, metaheuristic, and other AI-based MPPT techniques, wherein various parameters such as array size, irradiance levels, techniques considered, % boost in GMPP using best technique, and tracking time, etc., are considered.

This research work is novel from other aspects as well, such as the following:


Structure of this work is as follows: The modeling of the PV cell is elaborated upon in Section 2 along with the effects of environmental factors. The partial shading effect is discussed in Section 3. MPPT techniques and their classification are elaborated upon in Section 4. Research gap findings are reported in Section 5. Challenges and further scope of the conducted effort are pointed out in Section 6, and paper is concluded in Section 7.
