A Multilevel Inverter for Photovoltaic Systems with Fuzzy Logic Control

Converters for photovoltaic (PV) systems usually consist of two stages: a dc/dc booster and a pulsewidth modulated (PWM) inverter. This cascade of converters presents efficiency issues, interactions between its stages, and problems with the maximum power point tracking. Therefore, only part of the produced electrical energy is utilized. In this paper, the authors propose a single-phase H-bridge multilevel converter for PV systems governed by a new integrated fuzzy logic controller (FLC)/modulator. The novelties of the proposed system are the use of a fully FLC (not requiring any optimal PWM switching-angle generator and proportional–integral controller) and the use of an H-bridge power-sharing algorithm. Most of the required signal processing is performed by a mixed-mode field-programmable gate array, resulting in a fully integrated System-on-Chip controller. The general architecture of the system and its main performance in a large spectrum of practical situations are presented and discussed. The proposed system offers improved performance over two-level inverters, particularly at low–medium power

Plug-n-Play smart sensor based on web service

In this paper, the authors present an implementation of a plug-n-play Web sensor based on Web service approach utilizing open source software and adopting low cost hardware architecture. After an introduction to the Web service technology, the problem of the dynamic services and one solution will be dealt. In this way, if it inserted a new sensor in a network, its services are automatically published without network reconfiguration. The sensor is presented in the framework of a hierarchical distributed system for metrological application of monitoring. Particular attention is devoted to synchronization problems among all devices that compose the proposed distributed system accounting characteristics of main synchronization standards. Measurement results are made available as Web services so that all users can build up their own applications. The particular metrological application chosen to show some preliminary results of distributed monitoring network is the monitoring of root mean square (RMS) values in three-phase power networks. A proper synchronization protocol was adopted in order to synchronize to different hardware sections of the sensor performing measurement