Issues Related to Power Quality for solar pv system.5 answersPower quality issues in solar PV systems include voltage sag, voltage swell, harmonics, non-linear load variations, voltage unbalance, current unbalance, and flicker. Various research papers propose solutions to these issues. Mishra et al. propose a double-stage triple-phase grid-connected solar PV system with an LCL filter to enhance power quality. Kumar et al. propose a concurrent UPQC scheme for improving power quality issues in grid-integrated solar PV systems. Barreto et al. analyze the quality of electricity produced by PV systems connected to the grid and recommend including individual harmonic distortion and frequency parameters in quality standards. Silva et al. review power quality issues in solar-powered fast charging stations and propose solutions for integrating PV systems, EVs, and FCS with the grid. Senthilkumar et al. design a dynamic voltage restorer (DVR) to address power quality issues in hybrid solar PV-PEMFC systems and demonstrate its effectiveness in improving power quality.
What are the main degradation mechanisms in photovoltaic panels?5 answersThe main degradation mechanisms in photovoltaic panels include potential induced degradation (PID), bypass diode failures in short circuit conditions, high light-induced degradation (LID), hotspots/shaded cells, cracked cells, physical change of the encapsulant material, metallization corrosion, and optical degradation such as discoloration, delamination, aging, and soiling. PID is affected by external environmental conditions such as irradiance, temperature, and humidity, with temperature being a common factor that affects all degradation modes. The degradation process is exponentially related to temperature, following an Arrhenius equation.
What are the current shortcomings of perovskite solar cells?4 answersPerovskite solar cells currently have several shortcomings that hinder their practical application. These include non-radiative charge recombination, mismatched absorption, and light-induced degradation, which affect the power conversion efficiency and operational stability. Another major concern is the poor stability of perovskite solar cells, which limits their commercialization potential. Additionally, the toxicity of lead-based active layers and the environmental impact of high-temperature processes, organic solvents, and certain materials used in perovskite solar cells raise concerns about their sustainability. The complex preparation processes and high cost of perovskite/silicon tandem solar cells also hinder their commercialization. However, efforts have been made to address these issues by incorporating rare-earth elements to improve efficiency and stability, and by using encapsulation and recycling techniques to extend the lifespan and prevent lead leakage. Further research is needed to overcome these challenges and make perovskite solar cells a clean and sustainable solar technology.
How does the displacement defect radiation of SiC power transistoraffect the electrical properties of the material?5 answersThe displacement defect radiation in SiC power transistors affects the electrical properties of the material. The on-current is degraded by 100% due to the displacement defect, which is generated near the emitter-gate region. The degradation is most severe when the trap is located at the N-pillar side of the main current path, and this degradation increases with the movement of the defect location to the gate side. The deepest defect energy level with EC - 1.55 eV exhibits considerable degradation, leading to a decrease in on-current and an increase in on-resistance. The breakdown voltage is unaffected by radiation displacement defects at room temperature but is significantly reduced at high temperatures due to the shorter depletion width caused by the displacement defect. Power dissipation, however, shows immunity to the displacement defect induced by radiation at both room temperature and high temperatures.
What are the challenges and opportunities in SiC research?5 answersWide-bandgap (WBG) power devices such as SiC devices offer opportunities for higher performance in terms of switching speed, voltage, and temperature. However, there are significant design challenges associated with these devices, including increased electromagnetic interference (EMI), current overshoot, and cross-talk effects. Several potential solutions have been proposed to fully exploit the benefits of SiC devices while mitigating their side-effects. SiC-based automotive traction drives require optimal operating conditions and performance, and considerations include gate threshold voltage, trans-conductance, and tolerance against extreme operating conditions. Reliability and durability of gate oxide and body diodes are also important for automotive applications. Additionally, the cost of SiC for automotive applications is a factor to consider. SiC power modules have been characterized and evaluated, showing lower switching loss and on-resistance compared to Si devices. A hybrid concept combining Si-IGBT with SiC-MOSFET has also been explored as a potential replacement solution.
Causes of underperformance of solar plants?5 answersThe underperformance of solar plants can be caused by various factors. One major factor is the accumulation of dust and dirt on the surface of the solar panels, which reduces their efficiency and power output. This dust soiling can be particularly problematic in desert and arid areas where solar plants are often located. Another factor is the presence of shadows cast by structures, weeds, and other objects, which can also decrease power generation. Additionally, high ambient temperatures and high concentrations of atmospheric dust in semi-arid and desert lands can lead to degradation of solar collectors' performance. It is important to regularly clean the solar panels and address any malfunctioning or breakdowns in the equipment to ensure optimal energy production and performance.