Low-Complexity Power-Balancing-Point Based Optimization for Photovoltaic Differential Power Processing

Differential power processing (DPP) is regarded as a promising architecture in solving mismatching issues among photovoltaic (PV) submodules. Although conventional total-minimum-power-point (TMPP)-based real-time optimization algorithm by using the distributed submodule-level maximum power point tracking and simultaneously the centralized total-minimum-power tracking shows effectiveness in maximizing the power yield. However, uneven power stress among DPP converters, large oscillations, high additional cost for communication among DPP converters, and complicated implementation hinder the practical application. This article proposed a low-complexity power balancing point-based optimization algorithm to reduce the system cost and size, improve the system efficiency, and realize the standardized modular design for DPP converters. Furthermore, simple submodule-level voltage equalization control is implemented to eliminate expensive communication and relieve the control complexity while guaranteeing high maximum-power-point efficiency. The proposed algorithm can reduce the power rating of DPP converters compared with conventional TMPP-based control, which is beneficial to the improvement of system cost, reliability, and lifetime. Both simulation and experimental results under various scenarios are provided to validate the advantages of the proposed algorithm

A solar irradiance estimation technique via curve fitting based on dual-mode Jaya optimization

Solar irradiance is a crucial environmental parameter for optimal control of photovoltaic (PV) systems. However, precise measurements of the solar irradiance are difficult since the irradiation sensors (i.e., pyranometer or pyrheliometer) are expensive and hard to calibrate. This paper proposes a cost-effective and accurate method for estimating the solar irradiance with a PV module via curve fitting. A dual-mode Jaya (DM-Jaya) optimization algorithm is introduced to extract the real-time value of solar irradiance from the measured PV characteristics data by using two search strategies. The step sizes of a random walk are taken from even and Lévy distribution distributions in different searching phases. Compared with the traditional irradiance sensors, the proposed estimator does not require additional circuit and obtains relatively lower error rates. A comparative study of seven population-based optimization algorithms for the optimal design of the estimator is presented. These algorithms include particle swarm optimization (PSO), cuckoo search (CS), Jaya, simulated annealing (SA), genetic algorithm (GA), supply-demand-based optimization (SDO), and the proposed DM-Jaya algorithm. Simulations and experimental results reveal that DM-Jaya outperforms the other optimization algorithms in terms of the estimation speed and accuracy

Novel Fast-Speed Partial-Shading-Tolerant Flexible Power Point Tracking for Photovoltaic Systems with Explicit Key Points Estimation

Recent power curtailment-based photovoltaic (PV) flexible power point tracking (FPPT) algorithms mainly adopted intricate curve fitting or sophisticated curve-scanning mecha-nisms to ensure the grid supportive functionalities under partial shading conditions (PSCs), showing the limitations of mathe-matical solidity or system dynamics improvement. Accordingly, a novel fast-speed partial-shading-tolerant FPPT (PST-FPPT) algorithm is proposed in this paper. Regarding the proposed scheme, a modified explicit PV model is developed to express the key operation points with the assistance of several representative current-voltage samples from the initialization process, which is beneficial to computational burden reduction and irradiance sensors removal. Additionally, to guarantee the tracking speed to system dynamics, a set point estimation-based direct voltage regulation strategy is proposed in this paper, eliminating the redundant searching in approaching the predefined power com-mand. Simulation and experimental evaluations under various PSCs and operational circumstances validated the effectiveness of the proposed control

Supplementary document for Highly Stable Mixed-phase Cs-Cu-I Films with Tunable Optoelectronic Properties for UVB Photodetector Applications - 6774642.pdf

Fig.S1-3 Surface SEM, Fig.S4 XRD peak, Fig.S5 Crystal structure Fig.S6 SEM sectional view Fig. S7 Ideality facto

Supplementary document for Highly Stable Mixed-phase Cs-Cu-I Films with Tunable Optoelectronic Properties for UVB Photodetector Applications - 6733898.pdf

Fig.S1-3 Surface SEM, Fig.S4 XRD peak, Fig.S5 Crystal structur