Developing a green and sustainable economy with minimal environmental pollution is the current and main global goal. Therefore, the use of renewable energy sources has been researched and encouraged worldwide. Among the available renewable energy sources, solar energy has attracted significant research attention. For instance, Japan has marked great strides in generation and utilization of photovoltaic power especially as a supplement to electric power shortage. Lately, the spread of photovoltaic systems globally has led to extensive research work targeting enhancing their efficiency in terms of materials, power storage, cost to fit various applications and economic constraints. For example, different materials exhibit different energy structure that further influences the power generation characteristics of the photovoltaic modules. However, the development of new cell structures has enhanced energy conversion efficiency.
Today, numerical simulation has been employed in the design and development stages of photovoltaic systems to get an insight into their real-life application performances and characteristics. This has been a major landmark not only in establishing the control methods of various photovoltaic systems but also in investigating the operating conditions, design and developing of new systems as well as development of better photovoltaic systems management strategies. Unfortunately, the fact that photovoltaic systems are installed outdoors has resulted in degradation due to severe temperature and humidity conditions. This has affected their general performance and commercial installation. In recent studies, various techniques for detection and diagnosis of degradation in photovoltaic modules have been proposed. The diagnostic accuracy of these methods i.e. quantitative and remote supervision methods is affected by weather and temperature conditions thus leading to false results. To this end, the development of accurate methods for determining the degradation level in individual photovoltaic models is highly desirable.
In a recent paper published in the journal, Energy Conversion and Management, Ibaraki University researchers: Dr. T. Tanaka, T. Hayashi (graduate student), T. Nagayama and Professor T. Yanagidaira together with Professor Y. Inui from The University of Shiga Prefecture proposed a new degradation diagnosis method based on the xenon lighting system and a capacitor. The system is connected to the photovoltaic module output to enable degradation detection. First, the authors cross-examined the degradation patterns of different photovoltaic modules and formulated the apparatus set up and the sensing and diagnosis principles. Furthermore, numerical simulations were carried out to investigate the performance of the proposed method and compared to the experimental results.
A small unavoidable measurement error of the internal resistance of 2% less than its variation width was obtained. Moreover, by using the capacitor voltage as the diagnosis index, the fault of the bypass diode was accurately obtained. This confirmed the feasibility of the proposed degradation diagnosis method. To actualize the study, the authors conducted a prototyped based experiment and further investigated its applicability and performance in real photovoltaic modules. Interestingly, the same accuracy levels were observed in both simulations and experiments. In general, the xenon lighting systems are portable and have a low power consumption and thus fit for outdoor photovoltaic systems. Therefore, the study by Tadashi Tanaka and colleagues makes the proposed novel degradation diagnosis method for photovoltaic module viable in niche applications such as outdoor photovoltaic power plants.
Tanaka, T., Hayashi, T., Nagayama, T., Yanagidaira, T., & Inui, Y. (2019). Proposal of novel degradation diagnosis method for photovoltaic module employing xenon flash lighting system and detector capacitor. Energy Conversion and Management, 186, 450-461.Go To Energy Conversion and Managment