Page 66 - libroBrevetti

Department of Engineering, ICT and Technologies for Energy and Transport Patent Title Method and related system for the conversion of mechanical energy, coming from a turbine- generator set, to electrical energy. Ref. CNR 10253 Assignee(s): CNR CNR InsƟƚute: ISSIA Main Inventor: Gianpaolo Vitale Countries: IT, PCT Priority date: 08/05/2013 Abstract The present inveŶƟŽn refers to a Micro Wind Energy Conversion System ( WECS). It allows energy coming from a synchronous generator, supplied by a verƟcal-axis Darrieus wind turbine, to be injected into the ŶĂƟonal single-phase low-voltage grid. Among those known from the literature, the simplest architecture has been chosen for the power stage, which implies the best compromise between cost and performance. As the wind speed varies and transfers power to the turbine, the system is able to compute and to reach the angular speed that allows to extract the maximum available power (MPPT, maximum power point tracking). The system has been conceived for performing such task without using mechanical sensors for the measurement of wind speed and angular speed. This implies an increased reliability and a lower cost. Background The device belongs to the class of Micro Wind Energy Conversion System ( WECS), to be connected to the nĂƟonal single-phase low-voltage grid. It covers a power range from 1 kW to 10 kW. Currently, few devices on the market belong to this class and range. Anyway, those devices are derived from systems, whose hardware architecture and control system have been devised for the Photovoltaic segment and, thus, their performance is quite poor. Technology The system tracks the maximum power exploiƟng a neural network, which operates as a virtual anemometer, and using an electronic circuit that acts as a virtual encoder. Therefore, mechanical sensors are not needed, enabling to achieve a higher reliability and a lower cost. The control logic has been implemented on a FPGA plaƞorm. This architecture implies a higher working frequency and the true parallel ĞdžĞĐƵƟŽn of several tasks. Advantages and ApplicaƟons The ŝŶǀĞŶƟŽn solves the problem of dead ƟŵĞƐ in the MPPT transients within WECS employing permanent magnet synchronous machines, without using mechanical sensors (encoder/anemometer). Therefore, the yielded energy is higher, compared to a tradiƟonal system, especially at low wind speed, and an increase of reliability and robustness is obtained. Development stage The invenƟon has already been experimentally tested, by building a prototype at the laboratory of CNR ISSIA - UOS of Palermo. In ƉĂƌƟĐƵůĂƌ, the wind turbine has been emulated starƟng from its torque-speed characteriƐƟc, and the system has been successfully connected to the grid. A contract is about to be signed for transferring the developed technology to a Sicilian consoƌƟum. 57