Solar photovoltaic (PV) energy has witnessed double-digit growth in the past decade. The penetration of PV systems as distributed generators in low-voltage grids has also seen significant attention. In addition, the need for higher overall grid efficiency and reliability has boosted the interest in the microgrid concept. High-efficiency PV-based microgrids require maximum power point tracking (MPPT) controllers to maximize the harvested energy due to the nonlinearity in PV module characteristics. Perturb and observe (PO second, no steady-state oscillations around the MPP; and lastly, no need for predefined system-dependent constants, hence provides a generic design core. A design example is presented by experimental implementation of the proposed technique. Practical results for the implemented setup at different irradiance levels are illustrated to validate the proposed technique.

High-Performance Adaptive Perturb and Observe MPPT Technique for Photovoltaic-Based Microgrids

It has become imperative for the power and energy engineers to look out for the renewable energy sources such as sun, wind, geothermal, ocean and biomass as sustainable, cost-effective and environment friendly alternatives for conventional energy sources. However, the non-availability of these renewable energy resources all the time throughout the year has led to research in the area of hybrid renewable energy systems. In the past few years, a lot of research has taken place in the design, optimization, operation and control of the renewable hybrid energy systems. It is indeed evident that this area is still emerging and vast in scope. The main aim of this paper is to review the research on the unit sizing, optimization, energy management and modeling of the hybrid renewable energy system components. Developments in research on modeling of hybrid energy resources (PV systems), backup energy systems (Fuel Cell, Battery, Ultra-capacitor, Diesel Generator), power conditioning units (MPPT converters, Buck/Boost converters, Battery chargers) and techniques for energy flow management have been discussed in detail. In this paper, an attempt has been made to present a comprehensive review of the research in this area in the past one decade.

Hybrid renewable energy systems for power generation in stand-alone applications: A review

The photovoltaic (PV) system is one of the renewable energies that attract the attention of researchers in the recent decades. The PV generators exhibit nonlinear I–V and P–V characteristics. The maximum power produced varies with both irradiance and temperature. Since the conversion efficiency of PV arrays is very low, it requires maximum power point tracking (MPPT) control techniques. The maximum power point tracking (MPPT) is the automatic control algorithm to adjust the power interfaces and achieve the greatest possible power harvest, during moment to moment variations of light level, shading, temperature, and photovoltaic module characteristics. The purpose of the MPPT is to adjust the solar operating voltage close to the MPP under changing atmospheric conditions. It has become an essential component to evaluate the design performance of PV power systems. This investigation aims to assess different MPPT techniques, provide background knowledge, implementation topology, grid interconnection of PV and solar microinverter requirements presented in the literature, doing depth comparisons between them with a brief discussion. The MPPT merits, demerits and classification, which can be used as a reference for future research related to optimizing the solar power generation, are also discussed. Conventional methods are easy to implement but they suffer from oscillations at MPP and tracking speed is less due to fixed perturb step. Intelligent methods are efficient; oscillations are lesser at MPP in steady state and tracked quickly in comparison to conventional methods.

MPPT techniques for photovoltaic applications

In this paper, the concept of power tracking for PV systems is highlighted and an overview on 40 old and recent Maximum Power Point Tracking (MPPT) methods, available in the literature, is presented and classified. These methods are mathematically modeled and presented in such a way the reader can select the most appropriate method for his own application. A comparative table is presented at the end of the paper to simplify the classification of the different methods.

General review and classification of different MPPT Techniques

Unfilled gap of prolonged energy demand by conventional energy sources and consent of global warming as its vulnerable outcome provides a vent to search compatible option. Augmentation in use of solar energy reveled through last 3 decades portrays its heterogeneous rewards in the prevailing energy scenario. Nevertheless solar PV system arises as viable option in the critical power system era its low efficiency energy conversion attribute necessitates an efficient power conversion system. The nonlinearity of I–V (current–voltage) characteristic and its alteration for an assorted insolation and temperature values may enable the alteration in terminal voltage. This may deviates maximum power point due to which the available maximum power delivery to load can be differed. Literature of this field reiterated that the uniform insolation and partial shading condition demands undeniable need of maximum power point tracking. Nonetheless through investigation in this direction furnishes the availability of a bunch of such techniques; each of them posses its own pros and cones. This ubiquitous trait of available maximum power point tracking (MPPT) techniques unfolds the complexity in its precise selection. To diminish such complexity this paper offers a state of art of various MPPT technique and their comprehensive comparative analysis based on 110 standard research articles. The focus of this paper is to offer a better commencement and to furnish valued information for investigators of this field.

Maximum power point tracking (MPPT) techniques: Recapitulation in solar photovoltaic systems

Use of solar energy using photovoltaic (PV) arrays is emphasized increasingly and regarded as an important resource of power energy in the coming years As the power supplied by PV arrays depends upon the insolation, temperature and array voltage, it is necessary to control the operating point to extract the maximum power from the PV arrays Number of methods for maximum power point tracking (MPPT) has been reported in the literature This paper aims to give a comprehensive comparison of different MPPT algorithms in terms of their tracking efficiencies, cost effectiveness, complexity of realization etc Here the methods are classified according to the parameters they use in finding MPP, viz, PV voltage, PV current, output voltage, and output current

Maximum Power Point Algorithm in PV Generation: An Overview

Retting of banana pseudostem fibre using Bacillus strains to get excellent mechanical properties as biomaterial in textile & fiber industry

Integrated weed management to manage complex weed flora in turmeric

Evaluation of the Co-inoculation Effect of Rhizobium and Plant Growth Promoting Non-rhizobial Endophytes on Vigna radiata

Entomopathogenic fungi Metarhizium species are generally employed to manage the soil-dwelling stage of insect pests, and are known for their rhizocompetency property. Since this fungus is typically recommended for use in soil, it could potentially be investigated as a bioinoculant to reduce abiotic stress, such as salinity, along with improved plant growth promotion. Salt stress tolerance potential of native Metarhizium isolates was evaluated based on mycelial fresh weight, dry weight, and spore yield. All the isolates were found to tolerate NaCl concentrations (50 mM, 100 mM, 150 mM, 200 mM, 250 mM, and 300 mM) supplemented in the culture medium. Metarhizium anisopliae (AAUBC-M15) and Metarhizium pinghaense (AAUBC-M26) were found to be effective at tolerating NaCl stress up to 200 mM NaCl. These two isolates were analyzed in vitro for plant growth-promoting traits at elevated salt concentrations (100 and 200 mM NaCl). No significant effect on IAA production was reported with the isolate M. pinghaense (AAUBC-M26) (39.16 µg/mL) or in combination with isolate M. anisopliae (AAUBC-M15) (40.17 µg/mL) at 100 mM NaCl (38.55 µg/mL). The salinity stress of 100 mM and 200 mM NaCl had a significant influence on the phosphate solubilization activity, except in the co-inoculation treatment at 100 mM NaCl. The isolates were positive for ACC deaminase enzyme activity. An increase in salt concentration was accompanied by a steady and significant increase in chitinase enzyme activity. Total phenolics (149.3 µg/mL) and flavonoids (79.20 µg/mL) were significantly higher in the culture filtrate of Metarhizium isolates at 100 mM NaCl, and gradual decline was documented at 200 mM NaCl. M. pinghaense (AAUBC-M26) proved to be promising in reducing the salt stress in tomato seedlings during the nursery stage. In the pot culture experiment, the treatment comprising soil application + seedling root dip + foliar spray resulted in improved growth parameters of the tomato plant under salt stress. This study shows that Metarhizium, a fungus well known for controlling biotic stress brought on by insect pests, can also help plants cope with abiotic stress, such as salinity.

H.K. Patel

Papers

Maximum Power Point Algorithm in PV Generation: An Overview

Retting of banana pseudostem fibre using Bacillus strains to get excellent mechanical properties as biomaterial in textile & fiber industry

Integrated weed management to manage complex weed flora in turmeric

Evaluation of the Co-inoculation Effect of Rhizobium and Plant Growth Promoting Non-rhizobial Endophytes on Vigna radiata

Plant Growth-Promoting Potential of Entomopathogenic Fungus Metarhizium pinghaense AAUBC-M26 under Elevated Salt Stress in Tomato