Interleaved high-gain boost converter powered by solar energy using hybrid-based MPP tracking technique

This paper presents a solar-powered interleaved high-gain boost converter(IHGBC)that increases voltage gain with fewer ripples in the output voltage in comparison to existing DC-DC converters.The goal of this research is to develop a hybrid-based maximum power point tracking(MPPT)approach with the combination of a flower pollination(FP)algorithm assisted with a perturb&observe(P&O)MPPT approach for solar photovoltaic(SPV)systems integrated with IHGBC.To ensure effective usage of both FP and P&O algorithms,this study incorporates and validates the hybrid-based MPPT approach.The proposed solar-powered IHGBC with a hybrid-based MPPT algorithm has been computationally modelled and simulated using MATLAB®and Simulink®for both uniform and non-uniform irradiation and analysed for voltage gain,ripples in the output waveforms and convergence time.The proposed hybrid-based MPPT is based on a number of flowers that forecast the initial global peak,assisted by P&O in the last stage for faster convergence to attain the maximum power point(MPP).As a result,the hybrid-based MPPT approach alleviates the computational issues encountered in P&O and FP-based MPP approaches.The proposed hybrid MPPT is compared with conventional MPPT for SPV and the results show that the solar-powered IHGBC using a hybrid-based MPPT technique has negligible oscillations of 0.14%with a high-voltage gain of 7.992 and a fast convergence rate of 0.05 seconds compared to individual P&O-based MPPT and FP-based MPPT techniques.The simulation results of the proposed MPPT with IHGBC outperform the conventional MPPT with high-gain converters.

Atomic tracking of thermally-driven structural evolution in 2D crystals:Case of NbSe_(2)

Advanced atomic tracking techniques play a critical role in characterizing structural evolution,elucidating fundamental mechanisms of exotic phenomena and tailoring delicate properties.Thermally driven structural modulation in 2D crystals,such as the charge density wave(CDW),often leads to intriguing quantum properties,making them a valuable platform for exploring fundamental physics and potential device applications.However,despite their significance,experimental studies addressing atomic tracking of thermally-driven structural evolution in 2D crystals have been limited.Herein,we utilize high-accuracy variable-temperature atomic tracking measurements with scanning tunneling microscopy(STM)to directly observe a series of structural transitions in a model 2D crystal,namely NbSe_(2).With the atomic tracking technique,we confirm the existence of the universal thermally-driven CDW transition hysteresis between the heating and cooling cycles.This transition hysteresis,characterized by a constant temperature offset,represents a new phenomenon of structural evolution.Our findings provide a feasible method to track CDW transitions at the atomic scale in 2D crystals,significantly contributing to a better understanding and the potential modulation of these materials'functions in nanodevices.