Different diode configurations evaluation in photovoltaic arrays using binary coding method

This paper used a robust mathematical way (binary coding method) to study shadow effect in photovoltaic arrays. Binary coding method provides a way to define power generation index (PGI) as a factor which shows the performance of arrays at shadow condition. Different configurations of photovoltaic (PV) array show different behavior at shadow condition. Configurations behavior depends on modules interconnections, bypass and blocking diodes, and etc. Configuration which has better working condition should be chosen for PV array. In this paper all conventional configurations are analyzed and compared by the use of PGI value. Over currents which may create in some states of shadow is studied. Moreover, this paper deals with influence of working voltage range of inverter in maximum power point tracking. Finally, configurations are rated

Beta-backscattering thickness-meter design and evaluation with fuzzy TOPSIS method

An industrial gauge for measuring thickness of a gold coating layer deposited on a steel base through detection of the backscattered beta particles has been described. 3H, 14C and 63Ni pure beta emitters have been tested as the radioisotopic sources of the system individually in a fixed geometry. Analytical calculations have been performed in each case. Furthermore, simulations based on Monte Carlo stochastic technique (MCNP) have been processed. The obtained results from both methods have been compared to define the sensitivity of the system in each case. Finally for the first time, fuzzy TOPSIS method has been used for choosing the best source in the defined geometry for manufacturing, considering the following three criteria: (a) saturation thickness, (b) precision and (c) sensitivity. Results have shown that 3H source is the best alternative to the introduced measuring system