Polarization-insensitive broadband omni-directional anti-reflection in ZnO nanoneedle array for efficient solar energy harvesting

Broadband omni-directional anti-reflection characteristics have been an important issue because they can maximize the optical absorption in photovoltaic devices. Here, we investigate the optical properties of ZnO nanoneedle arrays to...

BODIPY-pyrene donor-acceptor sensitizers for triplet-triplet annihilation upconversion: the impact of BODIPY-core on upconversion efficiency

The triplet-triplet annihilation upconversion (TTA-UC) is an important type of optical process with applications in biophotonics, solar energy harvesting and photochemistry. In most of TTA-UC systems, the formation of triplet...

Climate and Sustainable Food Security

Agriculture is the world's largest solar energy harvesting enterprise. In the Indian context, the last few decades have witnessed unprecedented growth in agricultural production largely due to productivity improvement. However, the gap between potential yield and farmers fields is still high. This paper highlights the various socioeconomic issues that dominate the variability in agricultural production at the field level. Monsoon management of agriculture and human livelihoods has been a traditional experience in India. However, in the current context of wide spread concerns about global climatic change there is a need to translate climatic information into practical tools for the development and sustainment of agriculture. This paper makes a case for the development of a suitable strategy for climate management, in the context of the unique socio-economic structure of the country.

A Modified Multi-Winding DC–DC Flyback Converter for Photovoltaic Applications

DC–DC power converters have generated much interest, as they can be used in a wide range of applications. In micro-inverter applications, flyback topologies are a relevant research topic due to their efficiency and simplicity. On the other hand, solar photovoltaic (PV) systems are one of the fastest growing and most promising renewable energy sources in the world. A power electronic converter (either DC/DC or DC/AC) is needed to interface the PV array with the load/grid. In this paper, a modified interleaved-type step-up DC–DC flyback converter is presented for a PV application. The topology is based on a multi-winding flyback converter with N parallel connected inputs and a single output. Each input is supplied by an independent PV module, and a maximum power point tracking algorithm is implemented in each module to maximize solar energy harvesting. A single flyback transformer is used, and it manages only 1/N of the converter rated power, reducing the size of the magnetic core compared to other similar topologies. The design of the magnetic core is also presented in this work. Moreover, the proposed converter includes active snubber networks to increase the efficiency, consisting of a capacitor connected in series with a power switch, to protect the main switches from damaging dv/dt when returning part of the commutation energy back to the source. In this work, the operating principle of the topology is fully described on a mathematical basis, and an efficiency analysis is also included. The converter is simulated and experimentally validated with a 1 kW prototype considering three PV panels. The experimental results are in agreement with the simulations, verifying the feasibility of the proposal.