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Efficiency of maximum power point tracking in photovoltaic system under variable solar irradiance
(Division IV: Engineering Sciences of the Polish Academy of Sciences, 2014) Marańda, Witold; Piotrowicz, Maciej
Field conditions decrease the energy output of photovoltaic (PV) systems, mainly due to excessive temperatures. However, in regions with moderate ambient temperatures, as in Poland, solar energy is commonly delivered with highly fluctuating irradiance. This introduces yet another source of energy losses due to the non-ideal tracking of actual position of Maximum Power Point (MPP). Majority of PV-systems are equipped with DC/AC and grid-connected inverter. Since the solar energy flux is variable, an adequate MPP-tracking algorithm is required to handle a wide range of load levels and face rapid changes of input power. Along with the essential DC/AC conversion, the quality of MPP-tracking must also be taken into account in evaluation of inverter efficiency. The tracking in dynamic conditions has been addressed only recently. Several algorithms has been studied theoretically, experimentally or in laboratory conditions by applying artificial input test-patterns. This work takes the opposite approach by applying the recorded real-life solar irradiance and simulating the tracking behavior to study the problem for true field conditions in Poland. The simulation uses the unique high-quality irradiance data collected with 200 ms time resolution. The calculation of both static and dynamic MPP-tracking efficiency has been performed for representative variable-cloudy day, applying commonly used Perturb&Observe tracking algorithm.
Graphical user interface development for windows scripting
(Oficyna Wydawnicza Politechniki Wrocławskiej, 2009) Olczyk, Krzysztof; Marańda, Witold
Background: The computer software engineering market provides the developers with the multitude of various solutions: programming languages, platforms and frameworks to choose among. For automation of operating system administrative tasks (e.g. file manipulation, gluing applications, quick prototyping) the common choice is usually a scripting language (e.g. Bash, Perl, Tel, JScript) Motivation: It was identified that the standard Windows Script Host (WSH) for Microsoft Windows lacks a standardized and satisfactory technology for featuring its scripts with the functional graphical user interface. This recognition of the gap in Windows scripting led to the idea of providing the means of easy and robust definition of graphical user interface for scripting tasks in Windows environment (JScript / VBScript). Project: The aforesaid investigation led to the creation of the language/framework which provides the developers, experienced in windows scripting, with a tool to create standalone applications in the manner similar to creating desktop widgets or web pages. The description of an application user interface with the proposed language consist of an XML file binding script actions with tags corresponding to window control widgets from .NET Windows Forms library.